The effects of permafrost thaw on soil hydrologic, thermal, and carbon dynamics in an Alaskan peatland

USGS Publications Warehouse

O'Donnell, Jonathan A.; Jorgenson, M. Torre; Harden, Jennifer W.; McGuire, A. David; Kanevskiy, Mikhail Z.; Wickland, Kimberly P.

2012-01-01

Recent warming at high-latitudes has accelerated permafrost thaw in northern peatlands, and thaw can have profound effects on local hydrology and ecosystem carbon balance. To assess the impact of permafrost thaw on soil organic carbon (OC) dynamics, we measured soil hydrologic and thermal dynamics and soil OC stocks across a collapse-scar bog chronosequence in interior Alaska. We observed dramatic changes in the distribution of soil water associated with thawing of ice-rich frozen peat. The impoundment of warm water in collapse-scar bogs initiated talik formation and the lateral expansion of bogs over time. On average, Permafrost Plateaus stored 137 ± 37 kg C m-2, whereas OC storage in Young Bogs and Old Bogs averaged 84 ± 13 kg C m-2. Based on our reconstructions, the accumulation of OC in near-surface bog peat continued for nearly 1,000 years following permafrost thaw, at which point accumulation rates slowed. Rapid decomposition of thawed forest peat reduced deep OC stocks by nearly half during the first 100 years following thaw. Using a simple mass-balance model, we show that accumulation rates at the bog surface were not sufficient to balance deep OC losses, resulting in a net loss of OC from the entire peat column. An uncertainty analysis also revealed that the magnitude and timing of soil OC loss from thawed forest peat depends substantially on variation in OC input rates to bog peat and variation in decay constants for shallow and deep OC stocks. These findings suggest that permafrost thaw and the subsequent release of OC from thawed peat will likely reduce the strength of northern permafrost-affected peatlands as a carbon dioxide sink, and consequently, will likely accelerate rates of atmospheric warming.

Relationship between peat geochemistry and depositional environments, Cranberry Island, Maine

USGS Publications Warehouse

Raymond, R.; Cameron, C.C.; Cohen, A.D.

1987-01-01

The Heath, Great Cranberry Island, Maine, offers a unique locality for studying lateral and vertical relationships between radically different peat types within 1 km2. The majority of The Heath is a Sphagnum moss-dominated raised bog. Surrounding the raised bog is a swamp/marsh complex containing grass, sedge, Sphagnum moss, alder, tamarack, and skunk cabbage. Swamp/ marsh-deposited peat occurs both around the margins of The Heath and under Sphagnum-dominated peat, which was deposited within the raised bog. A third peat type, dominated by herbaceous aquatics, is present underlying the swamp/marsh-dominated peat but is not present as a dominant botanical community of The Heath. The three peat types have major differences in petrographic characteristics, ash contents, and associated minerals. Sulfur contents range from a low of 0.19 wt.% (dry) within the raised bog to a high of 4.44 wt% (dry) near the west end of The Heath, where swamp/marsh peat occurring directly behind a storm beach berm has been influenced by marine waters. The presence of major geochemical variations within a 1-km2 peat deposit suggests the need for in-depth characterization of potential peat resources prior to use. ?? 1987.

Pb inventory in an ombrotrophic bog decreases over time

NASA Astrophysics Data System (ADS)

Baumann, E.; Jeremiason, J.; Sebestyen, S.

2016-12-01

Peat cores were collected from the S2 ombrotrophic bog at the Marcell Experimental Forest (MEF) to determine if the Pb inventory in the bog has decreased over time. Pb concentrations in the outflow of the bog measured from 2009-2016 indicated continued mobilization and export of Pb out of the bog despite dramatic decreases in atmospheric deposition. A seminal study conducted by Urban et al. (1990) from 1981-1983 calculated a mass balance of Pb in the S2 watershed which included a Pb inventory in peat based on the approximate time frame of 1930 to 1983. We collected peat cores in 2016 to compare peat inventories of Pb over the same time range. We found that Pb inventories in the peat have decreased over time, consistent with Pb being mobilized by dissolved organic carbon (DOC) and gradually flushed out of the bog. Since 1983, DOC levels may have increased leading to further Pb mobilization and transport from the bog, but this trend is unclear. In contrast to Pb concentrations in the outflow water, upland runoff and the surface sphagnum moss layer have dramatically lower Pb concentrations compared to 1980s levels indicating fast ecosystem responses to a decrease in Pb inputs in these compartments. However, the deeper peat layers near the water table are responding more slowly to the decrease in Pb inputs and historical Pb inputs continue to be mobilized and transported from the bog. Our results would be applicable to other trace metals, such as Hg, that bind strongly to DOC. For example, a dramatic decrease in Hg deposition would not result in near-term decreases in Hg out of the bog.

Contrasting vulnerability of drained tropical and high-latitude peatlands to fluvial loss of stored carbon

NASA Astrophysics Data System (ADS)

Evans, Chris D.; Page, Susan E.; Jones, Tim; Moore, Sam; Gauci, Vincent; Laiho, Raija; Hruška, Jakub; Allott, Tim E. H.; Billett, Michael F.; Tipping, Ed; Freeman, Chris; Garnett, Mark H.

2014-11-01

Carbon sequestration and storage in peatlands rely on consistently high water tables. Anthropogenic pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of peat-forming vegetation and exposure of previously anaerobic peat to aerobic decomposition. This can shift peatlands from net CO2 sinks to large CO2 sources, releasing carbon held for millennia. Peatlands also export significant quantities of carbon via fluvial pathways, mainly as dissolved organic carbon (DOC). We analyzed radiocarbon (14C) levels of DOC in drainage water from multiple peatlands in Europe and Southeast Asia, to infer differences in the age of carbon lost from intact and drained systems. In most cases, drainage led to increased release of older carbon from the peat profile but with marked differences related to peat type. Very low DOC-14C levels in runoff from drained tropical peatlands indicate loss of very old (centuries to millennia) stored peat carbon. High-latitude peatlands appear more resilient to drainage; 14C measurements from UK blanket bogs suggest that exported DOC remains young (<50 years) despite drainage. Boreal and temperate fens and raised bogs in Finland and the Czech Republic showed intermediate sensitivity. We attribute observed differences to physical and climatic differences between peatlands, in particular, hydraulic conductivity and temperature, as well as the extent of disturbance associated with drainage, notably land use changes in the tropics. Data from the UK Peak District, an area where air pollution and intensive land management have triggered Sphagnum loss and peat erosion, suggest that additional anthropogenic pressures may trigger fluvial loss of much older (>500 year) carbon in high-latitude systems. Rewetting at least partially offsets drainage effects on DOC age.

Water exchange in raised bogs: revised views especially in relation to biogeochemistry

NASA Astrophysics Data System (ADS)

Sirin, Andrey; Kravchenko, Irina; Yurova, Alla; Markina, Anastasiya

2017-04-01

Raised bogs are one of the most common and exciting mire type within the boreal zone and appear in the other zones including mountain regions in the tropics. They receive water and nutrients from the atmosphere and pore water stored in their domes is spaced above the surrounding area (up to 10 m in height). Traditionally it is assumed that water flow occurs mainly in a peat layer near to the surface and water transport is negligible in deeper layers (lvanov, 1981; Ingram, 1982; etc.). The «acrotelm/catotelm» paradigm on active and inert horizons for the peat above and below the lowest water level is still widely spread in peatland hydrology. However, recent studies have shown that deep water movement is much more dynamic in raised bogs than was previously thought (Sirin et al., 1997, Reeve et al., 2000; etc.). Relying on isotope studies we conclude that all the mounded strata of the raised bogs have relatively active water exchange although water residence time changes with depth. The study included two raised bogs, representing different typical hydrological conditions (underlain by outwash sands and moraine clay) at the Zapadnaya Dvina Peatland Field Station of the Institute of Forest Science RAS located 400 km west of Moscow (56 N, 32 E). Peatlands, among which raised bogs dominate, constitute > 30% of the area, and maximum peat thickness exceeds 7 m. To evaluate water residence time in peat strata specially determined mathematical model which include the equations of water mass and tritium balance, imbedded in a conceptual framework of water dynamics within a raised bog peat body, have been developed and tested. The results from isotope studies (3H, 18O, 2H) were additionally supported by geochemical (pH, Eh, electrical conductivity) and temperature long term monitoring, as well as dissolved CO2 and CH4 monitoring within vertical profiles of the studied raised bogs (Sirin et al., 1998). Later it was also supported by microbiology data of methane cycle in the profile of peat bogs (Kravchenko, Sirin, 2007). The obtained results confirm that the hydrological stratification of peat bogs is a more complicated picture than previously thought and need to be considered.

UAV based 3D digital surface model to estimate paleolandscape in high mountainous environment

NASA Astrophysics Data System (ADS)

Mészáros, János; Árvai, Mátyás; Kohán, Balázs; Deák, Márton; Nagy, Balázs

2016-04-01

Our method to present current state of a peat bog was focused on the possible use of a UAV-system and later Structure-from-motion algorithms as processing technique. The peat bog site is located on the Vinderel Plateau, Farcǎu Massif, Maramures Mountains (Romania). The peat bog (1530 m a.s.l., N47°54'11", E24°26'37") lies below Rugasu ridge (c. 1820 m a.s.l.) and the locality serves as a conservation area for fallen down coniferous trees. Peat deposits were formed in a landslide concavity on the western slope of Farcǎu Massif. Nowadays the site is surrounded by a completely deforested landscape, and Farcǎu Massif lies above the depressed treeline. The peat bog has an extraordinary geomorphological situation, because a gully reached the bog and drained the water. In the recent past sedimentological and dendrochronological researches have been initiated. However, an accurate 3D digital surface model also needed for a complex paleoenvironmental research. Last autumn the bog and its surroundings were finally surveyed by a multirotor UAV developed in-house based on an open-source flight management unit and its firmware. During this survey a lightweight action camera (mainly to decrease payload weight) was used to take aerial photographs. While our quadcopter is capable to fly automatically on a predefined flight route, several over- and sidelapping flight lines were generated prior to the actual survey on the ground using a control software running on a notebook. Despite those precautions, limited number of batteries and severe weather affected our final flights, resulting a reduced surveyed area around peat bog. Later, during the processing we looked for a reliable tool which powerful enough to process more than 500 photos taken during flights. After testing several software Agisoft PhotoScan was used to create 3D point cloud and mesh about bog and its environment. Due to large number of photographs PhotoScan had to be configured for network processing to get reliable results and resolution. Based on the sediment layers of the peat bog together with the generated 3D surface model the paleoenvironment, the largest paleowater level can be reconstructed and we can estimate the dimension of the landslide which created the basin of the peat bog.

Geochemical characteristics of peat from two raised bogs of Germany

NASA Astrophysics Data System (ADS)

Mezhibor, A. M.

2016-11-01

Peat has a wide range of applications in different spheres of human activity, and this is a reason for a comprehensive study. This research represents the results of an ICP-MS study of moss and peat samples from two raised bogs of Germany. Because of the wide use of sphagnum moss and peat, determining their geochemical characteristics is an important issue. According to the results obtained, we can resume that the moss samples from Germany are rich in Cu, As, Y, Zr, Nb, and REE. The geochemical composition of the bogs reflects the regional environmental features and anthropogenic influence.

SPRUCE S1 Bog Peat Depth Determined by Push Probe and GPR: 2009-2010

DOE Data Explorer

Slater, L. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hanson, P. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hook, L. A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.

2012-01-01

This data set reports the thickness of peat for the S1 Bog measured directly with manual push probes on September 21 and 22, 2009, and measured by ground penetrating radar (GPR) across transects from January 26 to February 2, 2010 and June 2 to June 9, 2010. Also included are interpolated values of peat depth from both probe and GPR data for the S1 Bog at 1 meter square horizontal resolution.

A New Appraisal of Northern Peatlands and Global Atmospheric Methane Over the Holocene

NASA Astrophysics Data System (ADS)

MacDonald, G. M.; Holmquist, J. R.; Kremenetski, K.; Loisel, J.

2015-12-01

Use of large databases of peat cores to examine linkages between northern peatlands and atmospheric CH4 over the Holocene has been prone to uncertainties regarding 1. comparability of radiocarbon techniques and material dated, 2. appropriate summed probability distributions, 3. spatial representativeness of the sites, particularly in capturing sites south of the subarctic, 4. potential impacts of local lateral peatland expansion versus continental-scale peatland initiation, particularly in the late Holocene, and 5. impacts of changes in the proportion of high methane-producing fens vs Sphagnum bogs. We present a comparison of radiocarbon measurements from conventional counts, atomic mass spectrometry and differing peat materials to demonstrate a general compatibility of the various types of dates. We compare and apply several summed probability distribution methods to minimize any statistical bias in our analysis. We then present our analysis of a new data set of 7571 peatland cores from 4420 sites that extend into the temperate zone. Of these, 3732 cores inform on lateral expansion and 329 dates constrain the timing of fen-bog transition. Based on these data in original and gridded form we show that widespread peat initiation commenced at 16 kcal yr BP and reached a maximum rate at 11-8 kcal yr BP. Most sites began as fens, and peak transition to bogs occurred between 5 and 3 kcal yr BP, with a 1000 year lag between Eurasia and North America. There is no global late Holocene increase in lateral expansion. Based on modeled northern peatland area and ratio of fen/bog sites, CH4 production from northern peatlands increased rapidly from 11 to 9 cal yr BP, followed by slower increase until reaching a maximum at 5 kcal yr BP at 25 Tg per yr. From 4 kcal yr BP to Present, bogs become a dominant feature in the northern peatland landscape and CH4 production decreased to reach modern-day levels at about 20 Tg per yr. Northern peatlands have been a key infleunce on global atmospheric methan variations but likely cannot account for the late Holocene increase in atmospheric CH4 experienced after 4 kcal yr BP.

High-resolution Record of Holocene Climate, Vegetation, and Fire from a Raised Peat Bog, Prince Edward Island, Canadian Maritimes

NASA Astrophysics Data System (ADS)

Peros, M. C.; Chan, K.; Ponsford, L.; Carroll, J.; Magnan, G.

2014-12-01

Raised peat bogs receive all precipitation and nutrients from the atmosphere and are thus widely used archives for information on past environments and climates. In this paper we provide high-resolution multi-proxy data from a raised bog from northeastern Prince Edward Island, located in the Gulf of St. Lawrence, Canada. We studied testate amoeba (a proxy for water table depth), macrocharcoal (a proxy for local-scale fire), peat humification (a proxy for decomposition), plant macrofossils (indicative of local-scale vegetation), and organic matter content (yielding carbon accumulation rates) from a 5.5 m long core lifted from the center of Baltic Bog. Eleven AMS radiocarbon dates show that peat accumulation began before 9000 cal yr BP and continued almost uninterrupted until the present. The macrofossil data show that a transition from a sedge-dominated fen to a sphagnum-dominated bog occurred around 8000 cal yr BP, and sphagnum remained dominant in the bog throughout most of the Holocene. A testate amoeba-based reconstruction of water table depth indicates that conditions were drier during the early Holocene (~8000 to 5000 cal yr BP) and became gradually wetter into the late Holocene. In addition, a number of higher frequency shifts in precipitation are inferred throughout the Holocene on the basis of the testate amoeba and humification results. The macrocharcoal evidence indicates fire—probably in the surrounding forest—was relatively more common during the early Holocene, perhaps due to drier climate conditions. A large influx of charcoal at around 2000 cal yr BP suggests the presence of one or more major fires at this time, and a concurrent decrease in the rate of peat accumulation indicates the fire may have affected the bog itself. The data from Baltic Bog is broadly comparable to other proxy data (in particular pollen studies) from the Canadian Maritimes. This work is important because it: 1) helps us better understand the role of hydroclimatic variability in influencing peat bog ecosystems; and 2), represents one of the few peat-based records of Holocene paleoclimate from the region.

The impact of 90 years of drainage works on some chemical properties of raised peat bog organic soils - case study from valley of the Upper San river in Polish Bieszczady Mts. (Eastern Carpathians).

NASA Astrophysics Data System (ADS)

Stolarczyk, Mateusz

2016-04-01

Wetland ecosystems, including raised peat bogs are characterized by a specific water conditions and unique vegetation, which makes peatland highly important habitats due to protection of biodiversity. Transformation of peat bog areas is particularly related to changes in the environment e.g. according to reclamation works. Drainage of peatlands is directly associated to the decrease of groundwater levels and lead to a number of changes in the chemical and physical properties of peat material, included contents of exchangeable cations in the surface layers of peat soils in the decession phase of peat development and release above compounds from the soil to ground or surface waters. The aim of the research was to determine the impact of extended drainage works on chemical composition of sorption complex of raised peat bog organic soils and identification the potential environmental effects of alkaline cations leaching to the surface waters. Research was carried out on the peat bogs located in the Upper San valley in Polish Bieszczady Mts. (Eastern Carpathians). Soil samples used in this study were collected from 3 soil profiles in 10 or 20 cm intervals to the approximately 130 cm depth. Laboratory analyses included determination of basic properties of organic material such as the degree of peat decomposition, ash content, soil pH and carbon, hydrogen, nitrogen concentrations. Additionally the amount of alkaline cations, exchangeable and extractable acidity was determined. Furthermore, the degree of saturation of the sorption complex with alkaline cations (V) and cation exchange capacity (CEC) are calculated. In order to evaluate the impact of the examined peat bog to the environment, also water samples were collected and ions composition was measured. The obtained results show that studied organic soils are oligotrophic and strongly acidic. In the case of organic material related to decession phase of peat development, as a result of the lengthy drainage works, increased pH values, changes in the morphology of the peat, high nitrogen contents and lower values of C/N ratios are noticed. The increased contents of calcium, occurred in soil layers comprised of moorsh forming process are probably the effect of peat mineralization process or changes in the chemistry and fluctuations of groundwater levels. As a result of above factors, increased calcium and magnesium concentrations in surface waters in the immediate vicinity of investigated bogs are observed.

Decadal changes in peat carbon accrual rates in bogs in Northern Minnesota

NASA Astrophysics Data System (ADS)

Fissore, C.; Nater, E. A.; McFarlane, K. J.

2017-12-01

Throughout the Holocene, peatland ecosystems have accumulated substantial amounts of carbon (C) and currently store about one third of all soil organic carbon (SOC) worldwide. Large uncertainty still persists on whether peatland ecosystems located in northern latitudes will continue to act as C sinks, or if the effects of global warming will have greater effects on decomposition processes than on net ecosystem production. We investigated decadal C accrual rates of the top 25 cm of peats in three Sphagnum-rich peatlands located in Northern Minnesota (two ombrotrophic bogs and one fen). We used radiocarbon analysis of Sphagnum cellulose and model fitting to determine peat ages, and peat FTIR spectroscopy to determine humification indices and relative decomposition of peat samples with depth. We had the scope to detect whether recent warming has had an effect on peat decomposition and C accumulation rates. Modeled C accumulation rates in the three peatlands during the past five decades ranged between 78 and 107 g C m-2 yr-1 in the top 25 cm analyzed in this study, values that are higher than the 22 to 29 g C m-2 yr-1 obtained for long-term (millennial) accumulations for the entire bog profiles. Peat IR spectra and C:N ratios confirm low levels of decomposition across the bog sites, especially in the uppermost parts of the peat. The fen site showed very limited decomposition across the entire sampled profile. Higher rates of C accumulation, combined with low decomposition rates close to the surface provide a good estimate of net primary productivity. As substrate decomposition progresses over time, net rates of accumulation decrease. Peat decomposition was more pronounced in the lower depths of the sampled cores in the two ombrotrophic bogs than in the fen, likely an effect of larger temporal variation in water table depth in the bogs than in the fen. Some of the variation in C accumulation and decomposition observed in our bogs and fen suggests that future C accumulation rates will also largely depend on the effect of warming on hydrology, rather than temperature alone.

The peats of Costa Rica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obando A, L.; Malavassi R, L.; Ramirez E, O.

The objectives of this investigation were: (1) to locate potential peat deposits in Costa Rica; (2) to estimate as closely as possible by representative sampling the amount of peat present in each deposit, and (3) to make a preliminary evaluation of the quality of the peat in each deposit. With information from soil maps and a 3-week survey of Costa Rica, it is estimated that a potential area of about 1000 km{sup 2} is covered by peat. Most of the peat area (about 830 km{sup 2}) is in northeastern Costa Rica in the Tortuguero area. An aerial survey identified themore » potential peat areas by the exclusive presence of the Yolillo palm. The next largest potential area of peat (about 175 km{sup 2}) is in the cloud-covered areas of the Talamanca Mountains. Some reconnaissance has been done in the Talamanca Mountains, and samples of the peat indicate that it is very similar to the sphagnum peat moss found in Canada and the northern US. Smaller bogs have been discovered at Medio Queso, El Cairo, Moin, and the Limon airport. Two bogs of immediate interest are Medio Queso and El Cairo. The Medio Queso bog has been extensively sampled and contains about 182,000 metric tons (dry) of highly decomposed peat, which is being used as a carrier for nitrogen-fixing bacteria. The El Cairo bog is sparsely sampled and contains about 1,300,000 metric tons of slightly decomposed dry peat. Plans are to use this peat in horticultural applications on nearby farms. 10 refs., 11 figs., 7 tabs.« less

Local Spatial Heterogeneity of Holocene Carbon Accumulation throughout the Peat Profile of an Ombrotrophic Northern Minnesota Bog

DOE PAGES

McFarlane, Karis J.; Hanson, Paul J.; Iversen, Colleen M.; ...

2018-05-30

Here, we evaluated the spatial heterogeneity of historical carbon accumulation rates in a forested, ombrotrophic bog in Minnesota to aid understanding of responses to an ongoing decade-long warming manipulation. Eighteen peat cores indicated that the bog has been accumulating carbon for over 11,000 years, to yield 176±40 kg C m –2 to 225±58 cm of peat depth. Estimated peat basal ages ranged from 5100 to 11,100 cal BP. The long-term apparent rate of carbon accumulation over the entire peat profile was 22±2 kg C m –2yr –1. Plot location within the study area did not affect carbon accumulation rates, butmore » estimated basal ages were younger in profiles from plots closer to the bog lagg and farther from the bog outlet. In addition, carbon accumulation varied considerably over time. Early Holocene net carbon accumulation rates were 30±6 g C m –2yr –1. Around 3300 calendar BP, net carbon accumulation rates dropped to 15±8 g C m –2yr –1until the last century when net accumulation rates increased again to 74±57 g C m –2yr –1. During this period of low accumulation, regional droughts may have lowered the water table, allowing for enhanced aerobic decomposition and making the bog more susceptible to fire. These results suggest that experimental warming treatments, as well as a future warmer climate may reduce net carbon accumulation in peat in this and other southern boreal peatlands. Furthermore, our we caution against historical interpretations extrapolated from one or a few peat cores.« less

Local Spatial Heterogeneity of Holocene Carbon Accumulation throughout the Peat Profile of an Ombrotrophic Northern Minnesota Bog

DOE Office of Scientific and Technical Information (OSTI.GOV)

McFarlane, Karis J.; Hanson, Paul J.; Iversen, Colleen M.

Here, we evaluated the spatial heterogeneity of historical carbon accumulation rates in a forested, ombrotrophic bog in Minnesota to aid understanding of responses to an ongoing decade-long warming manipulation. Eighteen peat cores indicated that the bog has been accumulating carbon for over 11,000 years, to yield 176±40 kg C m –2 to 225±58 cm of peat depth. Estimated peat basal ages ranged from 5100 to 11,100 cal BP. The long-term apparent rate of carbon accumulation over the entire peat profile was 22±2 kg C m –2yr –1. Plot location within the study area did not affect carbon accumulation rates, butmore » estimated basal ages were younger in profiles from plots closer to the bog lagg and farther from the bog outlet. In addition, carbon accumulation varied considerably over time. Early Holocene net carbon accumulation rates were 30±6 g C m –2yr –1. Around 3300 calendar BP, net carbon accumulation rates dropped to 15±8 g C m –2yr –1until the last century when net accumulation rates increased again to 74±57 g C m –2yr –1. During this period of low accumulation, regional droughts may have lowered the water table, allowing for enhanced aerobic decomposition and making the bog more susceptible to fire. These results suggest that experimental warming treatments, as well as a future warmer climate may reduce net carbon accumulation in peat in this and other southern boreal peatlands. Furthermore, our we caution against historical interpretations extrapolated from one or a few peat cores.« less

Increased tree establishment in Lithuanian peat bogs--insights from field and remotely sensed approaches.

PubMed

Edvardsson, Johannes; Šimanauskienė, Rasa; Taminskas, Julius; Baužienė, Ieva; Stoffel, Markus

2015-02-01

Over the past century an ongoing establishment of Scots pine (Pinus sylvestris L.), sometimes at accelerating rates, is noted at three studied Lithuanian peat bogs, namely Kerėplis, Rėkyva and Aukštumala, all representing different degrees of tree coverage and geographic settings. Present establishment rates seem to depend on tree density on the bog surface and are most significant at sparsely covered sites where about three-fourth of the trees have established since the mid-1990s, whereas the initial establishment in general was during the early to mid-19th century. Three methods were used to detect, compare and describe tree establishment: (1) tree counts in small plots, (2) dendrochronological dating of bog pine trees, and (3) interpretation of aerial photographs and historical maps of the study areas. In combination, the different approaches provide complimentary information but also weigh up each other's drawbacks. Tree counts in plots provided a reasonable overview of age class distributions and enabled capturing of the most recently established trees with ages less than 50 years. The dendrochronological analysis yielded accurate tree ages and a good temporal resolution of long-term changes. Tree establishment and spread interpreted from aerial photographs and historical maps provided a good overview of tree spread and total affected area. It also helped to verify the results obtained with the other methods and an upscaling of findings to the entire peat bogs. The ongoing spread of trees in predominantly undisturbed peat bogs is related to warmer and/or drier climatic conditions, and to a minor degree to land-use changes. Our results therefore provide valuable insights into vegetation changes in peat bogs, also with respect to bog response to ongoing and future climatic changes. Copyright © 2014 Elsevier B.V. All rights reserved.

Peat bogs and their organic soils: Archives of atmospheric change and global environmentalsignificance (Philippe Duchaufour Medal Lecture)

NASA Astrophysics Data System (ADS)

Shotyk, William

2013-04-01

A bog is much more than a waterlogged ecosystem where organic matter accumulates as peat. Peatlands such as bogs represent a critical link between the atmosphere, hydrosphere, and biosphere. Plants growing at the surface of ombrotrophic bogs receive nutrients exclusively from the atmosphere. Despite the variations in redox status caused by seasonal fluctuations in depth to water table, the low pHof the waters, and abundance of dissolved organic matter, bogs preserve a remarkably reproducible history of atmospheric pollution, climate change, landscape evolution and human history. For example, peat cores from bogs in Europe and North America have provided detailed reconstructions of the changing rates and sources of Ag, Cd, Hg, Pb, Sb, and Tl, providing new insights into the geochemical cycles of these elements, including the massive perturbations induced by human activities beginning many thousands of years ago. Despite the low pH, and perhaps because of the abundance of dissolved organic matter, bogs preserve many silicate and aluminosilicate minerals which renders them valuable archives of atmospheric dust deposition and the climate changes which drive them. In the deeper, basal peat layers of the bog, in the minerotrophic zone where pore waters are affected bymineral-water interactions in the underlying and surrounding soils and sediments, peat serves as animportant link to the hydrosphere, efficiently removing from the imbibed groundwaters such trace elements as As, Cu, Mo, Ni, Se, V, and U. These removal processes, while incompletely understood, are so effective that measuring the dissolved fraction of trace elements in the pore waters becomes a considerable challenge even for the most sophisticated analytical laboratories. While the trace elements listed above are removed from groundwaters (along with P and S), elements such as Fe and Mn are added to the waters because of reductive dissolution, an important first step in the formation of lacustrine Fe and Mn nodules. While these important chemical reactions have taken place silently and imperceptibly over millenia acrossthe Earth wherever climate and water allow bogs to form, at the same time, peat bogs represent an important component of the biosphere and provide a home to many unique plants and animals, thereby contributing to the vast biodiversity found on Earth.

Peat Bog Archives: from human history, vegetation change and Holocene climate, to atmospheric dusts and trace elements of natural and anthropogenic origin

NASA Astrophysics Data System (ADS)

Shotyk, William

2010-05-01

For at least two centuries, peat has been recognized as an excellent archive of environmental change. William Rennie (1807), for example, interpreted stratigraphic changes in Scottish bogs not only in terms of natural changes in paleoclimate, but was also able to identify environmental changes induced by humans, namely deforestation and the hydrological impacts which result from such activities. The use of bogs as archives of climate change in the early 20th century was accelerated by studies of fossil plant remains such as those by Lewis in Scotland, and by systematic investigations of pollen grains pioneered by von Post in Sweden. In Denmark, Glob outlined the remarkably well-preserved remains of bog bodies and associated artefacts (of cloth, wood, ceramic and metal) in Danish bogs. In Britain, Godwin provided an introduction to the use of bogs as archives of human history, vegetation change, and Holocene climate, with a more recent survey provided by Charman. Recent decades have provided many mineralogical studies of peat and there is growing evidence that many silicate minerals, whether derived from the surrounding watershed or the atmosphere (soil-derived dusts and particles emitted from volcanoes), also are well preserved in anoxic peatland waters. Similarly, geochemical studies have shown that a long list of trace metals, of both natural and anthropogenic origin, also are remarkably well preserved in peat bogs. Thus, there is growing evidence that ombrotrophic (ie 'rain-fed') peat bogs are reliable archives of atmospheric deposition of a wide range of trace elements, including conservative, lithogenic metals such as Al, Sc, Ti, Y, Zr, Hf and the REE, but also the potentially toxic Class B, or 'heavy metals' such as Cu, Ag, Hg, Pb, Sb and Tl. When high quality measurements of these elements is combined with accurate radiometric age dating, it becomes possible to create high resolution reconstructions of atmospheric soil dust fluxes, ancient and modern metal pollution, and Holocene climate change.

A geospatial model to quantify mean thickness of peat in cranberry bogs

USDA-ARS?s Scientific Manuscript database

Commercial cranberry (Vaccinium macrocarpon Ait.) is cultivated on peatlands, which consist of sedimentary deposits of peat capped by a 0.3-1 m of artificial sand. Despite distinct soil layering, a general paucity of information exists on the physical properties of cranberry bogs. Field measurements...

A geospatial model to quantify mean thickness of peat in cranberry bogs

USDA-ARS?s Scientific Manuscript database

Commercial cranberry (Vaccinium macrocarpon Ait.) is cultivated on peatlands, which consist of sedimentary deposits of peat capped by a 0.3-1 m of artificial sand. Despite distinct soil layering, a general paucity of information exists on the physical properties of cranberry bogs. Field measurement...

Eutrophic mire, its characteristics and modern conditions of peat genesis

NASA Astrophysics Data System (ADS)

Inisheva, L. I.; Golubina, O. A.; Zaplatnikova, Yu. D.; Dubrovskaya, L. I.

2009-04-01

The study of structure functional organization of Siberian mire ecosystems is the base of after-effects influence of their reclamation on global changes of biosphere. The aim of this investigation is to study the structure functional organization of eutrophic mire ecosystem "Tagan". Peat deposit "Tagan" (West Siberia, 20 kilometers near Tomsk) is situated on the second flood-plain terrace of the river Tom of ancient flow channel. Maximum power of peat deposit is 9.3 meters. Subsoil is made up from sand, more seldom from loamy sand and loam. Eutrophic vegetation covers almost the whole mire. It is presented by woody sedge, sedge, sedge-moss and grass undershrub phytocenoses. The oligotrophic vegetation is presented by Sphagnum pine cotton-grass phytocenosis. There were organized three observation points on the mire in 2007. They watched dynamics of hydrothermic, redox, biological, hydrochemical regimes. There were studied physicochemical properties at given points. Peats with normal ash basically refer to grass, woody grass group of lowland type. They are characterized by high degree of decomposition which is increased down deposit. Group composition of organic matters of investigated peats showed that bitumen content in peat changes from 1.4 to 3.56%, and humid acids content is within the limits of 16.67 - 44.34 %. Water-soluble and hardly-hydrolyzed matters are contained in quantity of 19.04 - 49.76% of the whole dry peat mass. The overall nitrogen content changes within the limits of 1.76 - 3.52%. It is presented mainly by fraction of unhydrolyzed nitrogen (72.07 - 95.67% of the whole nitrogen). Highly-hydrolyzed nitrogen is the most available reserve of mineral compound of nitrogen and its content changes within the limits of 0.18 - 4.79 of the overall nitrogen. 2008 year is characterized as an average year at conditions of moistening and heat providing. Investigations, made during this year, revealed the following results. Bog waters were kept at a surface level of 20 - 69cm in summer. Peat deposit heating up to 10˚ C was observed at a depth of 120cm. Oxidizing conditions are traced up to 40 - 60cm deep. There is gradual change into restoring conditions deep in peat deposit. Very reduction conditions are observed at a depth of 60cm. Weather conditions of 2008 year were favorable for biological processes activation. In the result of their manifestation hydrochemical composition of bog waters was formed. First of all, one should pay attention to weak alkaline reaction of bog waters. Calcium content in bog waters changes from 70.2 to 150.9 mg/l. One may state calcium removal from peat deposit of eutrophic mire into an outfall. The latter is the river which is flowing along the mire. Magnesium concentration in bog waters changed within the limits of 8.5 - 42.5 mg/l. It is important to note high content of iron in individual months - up to 17.8 mg/l. Organic matters content in bog waters, which are presented by humid acids (HA) and fulvic acids (FA), is HA 3.4 - 24.65 mg/l, FA 11.0 - 58.3 mg/l. Let's, first of all, examine dynamics of individual components in bog waters. Thus, content of calcium, water-soluble carbon, and fulvic acids naturally increased in July, when it was marked combination of high temperature and minor precipitation. Active iron in bog waters had the highest concentration in spring which had gradually decreased by September (from 18 and 8 mg/l to 0.1 mg/l). Preliminary obtained results reveal bog drainage occurring at present. It is followed also from the fact that there are favorable redox conditions in a meter layer of peat deposit and high degree of peats decomposition. The examination of dynamics of hydrothermic, biological and hydrochemical regimes also is evidence of biological processes activity in eutrophic mire "Tagan". This fact, in its turn, influences on hydrochemical compound formation of bog waters.

Untangling climatic and autogenic signals in peat records

NASA Astrophysics Data System (ADS)

Morris, Paul J.; Baird, Andrew J.; Young, Dylan M.; Swindles, Graeme T.

2016-04-01

Raised bogs contain potentially valuable information about Holocene climate change. However, autogenic processes may disconnect peatland hydrological behaviour from climate, and overwrite and degrade climatic signals in peat records. How can genuine climate signals be separated from autogenic changes? What level of detail of climatic information should we expect to be able to recover from peat-based reconstructions? We used an updated version of the DigiBog model to simulate peatland development and response to reconstructed Holocene rainfall and temperature reconstructions. The model represents key processes that are influential in peatland development and climate signal preservation, and includes a network of feedbacks between peat accumulation, decomposition, hydraulic structure and hydrological processes. It also incorporates the effects of temperature upon evapotranspiration, plant (litter) productivity and peat decomposition. Negative feedbacks in the model cause simulated water-table depths and peat humification records to exhibit homeostatic recovery from prescribed changes in rainfall, chiefly through changes in drainage. However, the simulated bogs show less resilience to changes in temperature, which cause lasting alterations to peatland structure and function and may therefore be more readily detectable in peat records. The network of feedbacks represented in DigiBog also provide both high- and low-pass filters for climatic information, meaning that the fidelity with which climate signals are preserved in simulated peatlands is determined by both the magnitude and the rate of climate change. Large-magnitude climatic events of an intermediate frequency (i.e., multi-decadal to centennial) are best preserved in the simulated bogs. We found that simulated humification records are further degraded by a phenomenon known as secondary decomposition. Decomposition signals are consistently offset from the climatic events that generate them, and decomposition records of dry-wet-dry climate sequences appear to be particularly vulnerable to overwriting. Our findings have direct implications not only for the interpretation of peat-based records of past climates, but also for understanding the likely vulnerability of peatland ecosystems and carbon stocks to future climate change.

Lateral expansion and carbon exchange of a boreal peatland in Finland resulting in 7000 years of positive radiative forcing

NASA Astrophysics Data System (ADS)

Mathijssen, Paul J. H.; Kähkölä, Noora; Tuovinen, Juha-Pekka; Lohila, Annalea; Minkkinen, Kari; Laurila, Tuomas; Väliranta, Minna

2017-03-01

Data on past peatland growth patterns, vegetation development, and carbon (C) dynamics during the various Holocene climate phases may help us to understand possible future climate-peatland feedback mechanisms. In this study, we analyzed and radiocarbon dated several peat cores from Kalevansuo, a drained bog in southern Finland. We investigated peatland succession and C dynamics throughout the Holocene. These data were used to reconstruct the long-term atmospheric radiative forcing, i.e., climate impact of the peatland since initiation. Kalevansuo peat records revealed a general development from fen to bog, typical for the southern boreal zone, but the timing of ombrotrophication varied in different parts of the peatland. Peat accumulation patterns and lateral expansion through paludification were influenced by fires and climate conditions. Long-term C accumulation rates were overall lower than the average values found from literature. We suggest the low accumulation rates are due to repeated burning of the peat surface. Drainage for forestry resulted in a nearly complete replacement of typical bog mosses by forest species within 40 years after drainage. The radiative forcing reconstruction suggested positive values (warming) for the first 7000 years following initiation. The change from positive to negative forcing was triggered by an expansion of bog vegetation cover and later by drainage. The strong relationship between peatland area and peat type with radiative forcing suggests a possible feedback for future changing climate, as high-latitude peatlands may experience prominent regime shifts, such as fen to bog transitions.

Heat transport in the Red Lake Bog, Glacial Lake Agassiz Peatlands

USGS Publications Warehouse

McKenzie, J.M.; Siegel, D.I.; Rosenberry, D.O.; Glaser, P.H.; Voss, C.I.

2007-01-01

We report the results of an investigation on the processes controlling heat transport in peat under a large bog in the Glacial Lake Agassiz Peatlands. For 2 years, starting in July 1998, we recorded temperature at 12 depth intervals from 0 to 400 cm within a vertical peat profile at the crest of the bog at sub-daily intervals. We also recorded air temperature 1 m above the peat surface. We calculate a peat thermal conductivity of 0.5 W m-1 ??C-1 and model vertical heat transport through the peat using the SUTRA model. The model was calibrated to the first year of data, and then evaluated against the second year of collected heat data. The model results suggest that advective pore-water flow is not necessary to transport heat within the peat profile and most of the heat is transferred by thermal conduction alone in these waterlogged soils. In the spring season, a zero-curtain effect controls the transport of heat through shallow depths of the peat. Changes in local climate and the resulting changes in thermal transport still may cause non-linear feedbacks in methane emissions related to the generation of methane deeper within the peat profile as regional temperatures increase. Copyright ?? 2006 John Wiley & Sons, Ltd.

Tracing of ca 800 yr old mining activity in peat bog using Pb elemental concentrations and isotope compositions.

NASA Astrophysics Data System (ADS)

Baron, S.; Carignan, J.; Ploquin, A.

2003-04-01

Sixty sites of slags have been documented on the Mont-Lozère in southern France. The petrographic analysis shows that slags are metallurgical wastes (800 to 850 yr BP) which certainly result from smelting activity for lead and silver extraction (Ploquin et al., 2001). The aims of this study are: 1) to trace the source of Pb ores which supplied the smelting sites, by using the Pb isotopic composition of several surrounding Pb deposits, 2) to evaluate the actual pollution caused by these slags, by using elemental and isotopic compositions of soils, water and vegetation, and 3) to document the pollution history of the region, by using elemental and isotopic compositions of peat bog cores collected in the neighbourhood of the historical smelting sites. The lead isotopic composition of galena collected in most surrounding ores is very similar to that of different slag samples. On the other hand, the high precision of the results allowed us to select the mineralised areas which were probably the ore sources. The Pb isotopic composition of slags is even more homogeneous: 208/206 Pb: 2.092±0.002; 206/207 Pb: 1.179±0.001; 208/204 Pb: 38.663±0.025; 207/204 Pb: 15.665±0.006; 206/204 Pb: 18.476±0.023, and will allow source tracing in the environment. The "Narses Mortes" peat bog, around which two smelting sites have been reported, is strongly minerotrophic and contains 8 to 60% ash. A 1.40 m core have been retrieved and divided into 58 individual samples. Minerotrophic peat bog records both atmospheric deposition, soils leaching and the grounwater influence. The measured metal concentrations are normalised to Al contents of peat bog samples and the metal/Al ratios are compared to that of the Mont-Lozère granite: relative excess in metal concentrations are found in peat bog samples. An increasing excess of most metals (Pb, Zn, Cd...) was measured for surface samples, from 55 cm depth to the top of the core (23 cm depth). This profil might be attributed to atmospheric input during the last centuries. Pb and As alone are also enriched in some deeper samples (between 120--90 cm depth). At the moment, no sedimentation rates are available for this section of the peat bog. However, according to palynological data (de Beaulieu, in progress), the bottom of the core might be as old as 5000 years BP. This would place the medieval activities at the base of the surface metal enrichment (˜55 cm depth), having no large effect in Pb concentrations measured in peat bog. The older Pb-As enrichment remain enigmatic and may correspond to earlier anthropogenic activities (2000--2500 BP), a period for which very few traces of metallurgical activities are found in Occidental Europe. 14C dating and Pb isotope works are going on peat bog samples trying to discriminate metals sources.

Identification of runoff formation with two dyes in a mid-latitude mountain headwater

NASA Astrophysics Data System (ADS)

Vlček, Lukáš; Falátková, Kristýna; Schneider, Philipp

2017-06-01

Subsurface flow in peat bog areas and its role in the hydrologic cycle has garnered increased attention as water scarcity and floods have increased due to a changing climate. In order to further probe the mechanisms in peat bog areas and contextualize them at the catchment scale, this experimental study identifies runoff formation at two opposite hillslopes in a peaty mountain headwater; a slope with organic peat soils and a shallow phreatic zone (0.5 m below surface), and a slope with mineral Podzol soils and no detectable groundwater (> 2 m below surface). Similarities and differences in infiltration, percolation and preferential flow paths between both hillslopes could be identified by sprinkling experiments with Brilliant Blue and Fluorescein sodium. To our knowledge, this is the first time these two dyes have been compared in their ability to stain preferential flow paths in soils. Dye-stained soil profiles within and downstream of the sprinkling areas were excavated parallel (lateral profiles) and perpendicular (frontal profiles) to the slopes' gradients. That way preferential flow patterns in the soil could be clearly identified. The results show that biomat flow, shallow subsurface flow in the organic topsoil layer, occurred at both hillslopes; however, at the peat bog hillslope it was significantly more prominent. The dye solutions infiltrated into the soil and continued either as lateral subsurface pipe flow in the case of the peat bog, or percolated vertically towards the bedrock in the case of the Podzol. This study provides evidence that subsurface pipe flow, lateral preferential flow along decomposed tree roots or logs in the unsaturated zone, is a major runoff formation process at the peat bog hillslope and in the adjacent riparian zone.

The peats of Costa Rica (in English; Spanish)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thayer, G.R.

Peat has been identified in Cost Rica, and an economic analysis of energy applications for peat has been done. About 1000 km{sup 2} of Cost Rica has the potential of being covered by peat. The Talamanca Mountains and the northeastern plains contain most of the Costa Rican peat. Specific bogs have been identified by the Medio Queso River in north-central Costa Rica and near El Cairo, Moin, and the Limon airport in northeastern Costa Rica. The Medio Queso bog, which is supplying peat for use as a carrier for nitrogen-fixing bacteria, and the El Cairo bog, which has been identifiedmore » as a source of horticultural peat for nearby ornamental plant farms, are of special interest. The economics of three energy applications of peat were examined -- as a fuel in large boilers, as a fuel in small boilers, and as an oil substitute in a cement plant. A facility using coal would have the same total costs as one using peat if coal prices were $45 and $30 per metric ton (used for large boilers and a cement plant, respectively). A facility using Bunker C or diesel would have the same total cost as one using peat if oil prices were $0.11, $0.08, and $0.06 per liter (used for large boilers, small boilers, and a cement plant, respectively). In all three cases, the costs for peat were comparable or less than the costs for coal and oil at 1987 prices. 6 refs., 8 figs.« less

Seasonal variations in CO2 and CH4 fluxes of four different plant compositions of a Sphagnum-dominated Alpine peat bog

NASA Astrophysics Data System (ADS)

Drollinger, Simon; Maier, Andreas; Karer, Jasmin; Glatzel, Stephan

2017-04-01

Peatlands are the only type of ecosystems which have the ability to accumulate significant amounts of carbon (C) under undisturbed conditions. The amount of C sequestered in peatlands depends on the balance between gross primary production, ecosystem respiration and decomposition of plant material. Sphagnum-dominated bogs possess the greatest peat accumulation potential of all peatlands, thus in turn, feature highest C release potentials. Many studies report about the C balances of undisturbed northern peat bogs, however, little is known about the effects of peatland degradation on the C balance between different plant compositions within peat bog ecosystems. Particularly in the Alpine region, where temperature increase during the last century has been almost twice as high as the global mean. The investigated peat bog is located in the inner Alpine Enns valley in the Eastern Alps, Austria (N 47˚ 34.873' E 14˚ 20.810'). It is a pine peat bog covered by Sphagnum mosses and a present extent of about 62 ha. Due to increasing differences in surface height of the peatland compared to the surrounding areas and related lowered water retention capacity attributed to the subsidence of the adjacent intensively managed meadows on deeply drained peat soils, the function of the peatland as a carbon sink is strongly endangered. Hence, the current mean water table depth of the central peat bog area is about -12 cm. To reveal differences in peatland-atmosphere C exchanges within the peatland ecosystem, we investigated CO2 and CH4 fluxes of four different vegetation compositions (PM1-PM4) at the treeless central peat bog area. PM1 is dominated by the graminoids Rhynchospora alba and Eriophorum vaginatum. PM2 is inhabited by small individuals (< 35 cm) of the conifer Pinus mugo, whereas PM3 is dominated by the ericaceous plant Calluna vulgaris. PM4 again is populated by Pinus mugo, but higher growing (35 - 60 cm) and with corresponding higher amount of biomass. Fluxes were measured for at least 120 seconds with the closed dynamic chamber method using infrared gas analysers (UGGA, Los Gatos Research and LI-802, LI-COR Biosciences) at four study sites with three replicates each. Net ecosystem exchange was measured using transparent chambers, whereas soil respiration was revealed using opaque chambers. Measurements were conducted seasonally during the last two years with eight sampling periods. Here, we demonstrate the seasonal variations in CO2 and CH4 fluxes, evaluate the underlying factors being responsible for these variations, examine the differences in diurnal pattern during the seasons and compute the global warming potentials of the released greenhouse gases. Moreover, we estimate the annual C balance per site and revise the seasonal C fluxes by comparing the results with fluxes derived by eddy covariance method.

The hydrology of several peat deposits in northern Minnesota, U.S.A.

Treesearch

R.R. Bay

1968-01-01

A comprehensive peatland hydrology study has provided data on the climate, hydrogeology, water table levels, and run-off from forested peat deposits in northern Minnesota. Groundwater studies identified two types of hydrogeologic situations-perched bogs, independent of the underground flow system, and groundwater bogs, which were influenced by storage changes in the...

Fine-root growth in a forested bog is seasonally dynamic, but shallowly distributed in nutrient-poor peat

Treesearch

Colleen M. Iversen; Joanne Childs; Richard J. Norby; Todd A. Ontl; Randall K. Kolka; Deanne J. Brice; Karis J. McFarlane; Paul J. Hanson

2017-01-01

Background and aims. Fine roots contribute to ecosystem carbon, water, and nutrient fluxes through resource acquisition, respiration, exudation, and turnover, but are understudied in peatlands. We aimed to determine how the amount and timing of fine-root growth in a forested, ombrotrophic bog varied across gradients of vegetation density, peat...

Dependency of Ecosystem Respiration in a Cool Temperate Bog on Peat Temperature and Water Table

NASA Astrophysics Data System (ADS)

Moore, T.; Lafleur, P.; Roulet, N.; Frolking, S.

2003-12-01

We measured ecosystem respiration (ER) from nighttime net ecosystem exchange of carbon dioxide determined from an eddy covariance tower located in a large ombrotrophic bog near Ottawa, Canada. Measurements were made from May to October over 5 years, 1998 to 2002. Ecosystem respiration ranged from <0.05 mg CO2/m2/s in spring (May) and late fall (late October) to 0.10-0.15 mg CO2/m2/s during the summer (July-August). As anticipated, there was a strong relationship between ER and peat temperatures, such as at a depth of 5 cm (r2 = 0.63). Q10 over 5° to 15° C varied from 2.2 to 4.2 depending upon the choice of temperature level and location within a hummock or hollow. Unexpected for a wetland ecosystem, there was only a weak relationship between ER and water table position (r2 = 0.11). Comparison of ER in early and late summer, 2002 with similar surface temperature revealed no significant difference in ER. A laboratory incubation of peat cores at different moisture contents showed that CO2 production was reduced by drying in the surface samples, but there was little decrease in samples from below a depth of 30 cm. We believe that the lack of correlation between ER and water table position in this ecosystem results from an increase in CO2 production at depth compensating a decrease in production of CO2 by heterotrophic respiration in the near surface layers and autotrophic respiration in the moss community.

Correlation between the morphogenetic types of litter and their properties in bog birch forests

NASA Astrophysics Data System (ADS)

Efremova, T. T.; Efremov, S. P.; Avrova, A. F.

2010-08-01

A formalized arrangement of morphogenetic types of litter according to the physicochemical parameters provided their significant grouping in three genetic associations. The litter group (highly decomposed + moderately decomposed) is confined to the tall-grass group of bog birch forests. The rhizomatous (roughly decomposed) litter is formed in the sedge-reed grass bog birch forests. The litter group (peaty + peatified + peat) is associated with the bog-herbaceous-moss group of forest types. The genetic associations of the litters (a) reliably characterize the edaphic conditions of bog birch forests and (b)correspond to formation of the peat of certain ecological groups. We found highly informative the acid-base parameters, the exchangeable cations (Ca2+ + Mg2+) and the total potential acidity, which differentiated the genetic associations of litter practically with 100% probability. The expediency of studying litters under groups of forest types rather than under separate types of bog birch forests was demonstrated.

Anomalous concentrations of zinc and copper in highmoor peat bog, southeast coast of Lake Baikal

NASA Astrophysics Data System (ADS)

Bobrov, V. A.; Bogush, A. A.; Leonova, G. A.; Krasnobaev, V. A.; Anoshin, G. N.

2011-08-01

When examining the peat deposit discovered in Vydrinaya bog, South Baikal region, the authors encountered anomalous Zn and Cu concentrations for highmoors being up to 600-500 ppm on a dry matter basis in the Early Holocene beds (360-440 cm) formed 11 000-8500 years ago. It has been demonstrated that Zn and Cu are present inside the plant cells of peat moss in the form of authigenic sulfide minerals of micron size. Apart from Zn and Cu, native Ag particles (5-7 um) have been encountered in the peat of the Vydrinaya bog at a depth of 390-410 cm; these particles formed inside the organic matter of the plasma membrane of peat moss containing Ca, Al, S, and Cu. This study suggests probable patterns of the formation of zinc sulfides, copper sulfides, and native silver in peat moss. The results obtained indicate that biogenic mineral formation plays a significant role in this system, which is a very important argument in the discussion on the ore genesis, in which physicochemical processes are normally favored, while the role of living matter is quite frequently disregarded.

Functioning of microbial complexes in aerated layers of a highmoor peat bog

NASA Astrophysics Data System (ADS)

Golovchenko, A. V.; Bogdanova, O. Yu.; Stepanov, A. L.; Polyanskaya, L. M.; Zvyagintsev, D. G.

2010-09-01

Monitoring was carried out using the luminescent-microscopic method of the abundance parameters of different groups of microorganisms in a monolith and in the mixed layers of a highmoor peat bog (oligotrophic residual-eutrophic peat soil) in a year-long model experiment. The increase of the aeration as a result of mixing of the layers enhanced the activity of the soil fungi. This was attested to by the following changes: the increase of the fungal mycelium length by 6 times and of the fungal biomass by 4 times and the double decrease of the fraction of spores in the fungal complex. The response of the fungal complex to mixing was different in the different layers of the peat bog. The maximal effect was observed in the T1 layer and the minimal one in the T2 layer. The emission of CO2 in the mixed samples was 1.5-2 times higher than that from the undisturbed peat samples. In contrast with the fungi, the bacteria and actinomycetes were not affected by the aeration of the highmoor layers.

Ground water and vegetation in two peat bogs in northern Minnesota

Treesearch

Roger R. Bay

1967-01-01

Plant cover and water quality of bog waters are related to the surrounding ground-water flow systems in two bogs--one perched above and isolated from the regional ground-water system, the other nonperched and continuous with the regional system. The nonperched bog has higher pH, higher specific conductivity, and greater variety in plant cover than the perched bog....

Water Table Depth Reconstruction in Ombrotrophic Peatlands Using Biomarker Abundance Ratios and Compound-Specific Hydrogen Isotope Composition

NASA Astrophysics Data System (ADS)

Nichols, J. E.; Jackson, S. T.; Booth, R. K.; Pendall, E. G.; Huang, Y.

2005-12-01

Sediment cores from ombrotrophic peat bogs provide sensitive records of changes in precipitation/evaporation (P/E) balance. Various proxies have been developed to reconstruct surface moisture conditions in peat bogs, including testate amoebae, plant macrofossils, and peat humification. Studying species composition of testate amoeba assemblages is time consuming and requires specialized training. Humification index can be influenced by environmental factors other than moisture balance. The plant macrofossil proxy is less quantitative and cannot be performed on highly decomposed samples. We demonstrate that the ratio of C23 alkane to C29 alkane abundance may provide a simple alternative or complementary means of tracking peatland water-table depth. Data for this proxy can be collected quickly using a small sample (100 mg dry). Water-table depth decreases during drought, and abundance of Sphagnum, the dominant peat-forming genus, decreases as vascular plants increase. Sphagnum moss produces mainly medium chain-length alkanes (C21-C25) while vascular plants (grasses and shrubs) produce primarily longer chain-length alkanes (C27-C31). Therefore, C23:C29 n-alkane ratios quantitatively track the water table depth fluctuations in peat bogs. We compared C23:C29 n-alkane ratios in a core from Minden Bog (southeastern Michigan) with water table depth reconstructions based on testate-amoeba assemblages and humification. The 184-cm core spans the past ~3kyr of continuous peat deposition in the bog. Our results indicate that the alkane ratios closely track the water table depth variations, with C29 most abundant during droughts. We also explored the use of D/H ratios in Sphagnum biomarkers as a water-table depth proxy. Compound-specific hydrogen isotope ratio analyses were performed on Sphagnum biomarkers: C23 and C25 alkane and C24 acid. Dry periods are represented in these records by an enrichment of deuterium in these Sphagnum-specific compounds. These events also correlate with drought events in the testate amoeba record and the alkane abundance ratio record. These biogeochemical proxies can be used in paleohydrological studies of ombrotrophic bogs and provide a new and complimentary source of data from these underutilized paleoclimate archives.

Temperature-Induced Increase in Methane Release from Peat Bogs: A Mesocosm Experiment

PubMed Central

van Winden, Julia F.; Reichart, Gert-Jan; McNamara, Niall P.; Benthien, Albert; Damsté, Jaap S. Sinninghe.

2012-01-01

Peat bogs are primarily situated at mid to high latitudes and future climatic change projections indicate that these areas may become increasingly wetter and warmer. Methane emissions from peat bogs are reduced by symbiotic methane oxidizing bacteria (methanotrophs). Higher temperatures and increasing water levels will enhance methane production, but also methane oxidation. To unravel the temperature effect on methane and carbon cycling, a set of mesocosm experiments were executed, where intact peat cores containing actively growing Sphagnum were incubated at 5, 10, 15, 20, and 25°C. After two months of incubation, methane flux measurements indicated that, at increasing temperatures, methanotrophs are not able to fully compensate for the increasing methane production by methanogens. Net methane fluxes showed a strong temperature-dependence, with higher methane fluxes at higher temperatures. After removal of Sphagnum, methane fluxes were higher, increasing with increasing temperature. This indicates that the methanotrophs associated with Sphagnum plants play an important role in limiting the net methane flux from peat. Methanotrophs appear to consume almost all methane transported through diffusion between 5 and 15°C. Still, even though methane consumption increased with increasing temperature, the higher fluxes from the methane producing microbes could not be balanced by methanotrophic activity. The efficiency of the Sphagnum-methanotroph consortium as a filter for methane escape thus decreases with increasing temperature. Whereas 98% of the produced methane is retained at 5°C, this drops to approximately 50% at 25°C. This implies that warming at the mid to high latitudes may be enhanced through increased methane release from peat bogs. PMID:22768100

Fine-root growth in a forested bog is seasonally dynamic, but shallowly distributed in nutrient-poor peat

DOE PAGES

Iversen, Colleen M.; Childs, Joanne; Norby, Richard J.; ...

2017-03-30

Fine roots contribute to ecosystem carbon, water, and nutrient fluxes through resource acquisition, respiration, exudation, and turnover, but are understudied in peatlands. Here, we aimed to determine how the amount and timing of fine-root growth in a forested, ombrotrophic bog varied across gradients of vegetation density, peat microtopography, and changes in environmental conditions across the growing season and throughout the peat profile. We quantified fine-root peak standing crop and growth using non-destructive minirhizotron technology over a two-year period, focusing on the dominant woody species in the bog: Picea mariana, Larix laricina, Rhododendron groenlandicum, and Chamaedaphne calyculata. The fine roots ofmore » trees and shrubs were concentrated in raised hummock microtopography, with more tree roots associated with greater tree densities and a unimodal peak in shrub roots at intermediate tree densities. Fine-root growth tended to be seasonally dynamic, but shallowly distributed, in a thin layer of nutrient-poor, aerobic peat above the growing season water table level. Finally, the dynamics and distribution of fine roots in this forested ombrotrophic bog varied across space and time in response to biological, edaphic, and climatic conditions, and we expect these relationships to be sensitive to projected environmental changes in northern peatlands.« less

Fine-root growth in a forested bog is seasonally dynamic, but shallowly distributed in nutrient-poor peat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iversen, Colleen M.; Childs, Joanne; Norby, Richard J.

Fine roots contribute to ecosystem carbon, water, and nutrient fluxes through resource acquisition, respiration, exudation, and turnover, but are understudied in peatlands. Here, we aimed to determine how the amount and timing of fine-root growth in a forested, ombrotrophic bog varied across gradients of vegetation density, peat microtopography, and changes in environmental conditions across the growing season and throughout the peat profile. We quantified fine-root peak standing crop and growth using non-destructive minirhizotron technology over a two-year period, focusing on the dominant woody species in the bog: Picea mariana, Larix laricina, Rhododendron groenlandicum, and Chamaedaphne calyculata. The fine roots ofmore » trees and shrubs were concentrated in raised hummock microtopography, with more tree roots associated with greater tree densities and a unimodal peak in shrub roots at intermediate tree densities. Fine-root growth tended to be seasonally dynamic, but shallowly distributed, in a thin layer of nutrient-poor, aerobic peat above the growing season water table level. Finally, the dynamics and distribution of fine roots in this forested ombrotrophic bog varied across space and time in response to biological, edaphic, and climatic conditions, and we expect these relationships to be sensitive to projected environmental changes in northern peatlands.« less

Effects of permafrost aggradation on peat properties as determined from a pan-Arctic synthesis of plant macrofossils

USGS Publications Warehouse

Treat, C.C.; Jones, Miriam C.; Camill, P.; Gallego-Sala, A.; Garneau, M.; Harden, Jennifer W.; Hugelius, G.; Klein, E.S.; Kokfelt, U.; Kuhry, P.; Loisel, Julie; Mathijssen, J.H.; O'Donnell, J.A.; Oksanen, P.O.; Ronkainen, T.M.; Sannel, A.B.K.; Talbot, J. J.; Tarnocal, C.M.; Valiranta, M.

2016-01-01

Permafrost dynamics play an important role in high-latitude peatland carbon balance and are key to understanding the future response of soil carbon stocks. Permafrost aggradation can control the magnitude of the carbon feedback in peatlands through effects on peat properties. We compiled peatland plant macrofossil records for the northern permafrost zone (515 cores from 280 sites) and classified samples by vegetation type and environmental class (fen, bog, tundra and boreal permafrost, and thawed permafrost). We examined differences in peat properties (bulk density, carbon (C), nitrogen (N) and organic matter content, and C/N ratio) and C accumulation rates among vegetation types and environmental classes. Consequences of permafrost aggradation differed between boreal and tundra biomes, including differences in vegetation composition, C/N ratios, and N content. The vegetation composition of tundra permafrost peatlands was similar to permafrost-free fens, while boreal permafrost peatlands more closely resembled permafrost-free bogs. Nitrogen content in boreal permafrost and thawed permafrost peatlands was significantly lower than in permafrost-free bogs despite similar vegetation types (0.9% versus 1.5% N). Median long-term C accumulation rates were higher in fens (23 g C m−2 yr−1) than in permafrost-free bogs (18 g C m−2 yr−1) and were lowest in boreal permafrost peatlands (14 g C m−2 yr−1). The plant macrofossil record demonstrated transitions from fens to bogs to permafrost peatlands, bogs to fens, permafrost aggradation within fens, and permafrost thaw and reaggradation. Using data synthesis, we have identified predominant peatland successional pathways, changes in vegetation type, peat properties, and C accumulation rates associated with permafrost aggradation.

Decoding the Secrets of Carbon Preservation and GHG Flux in Lower-Latitude Peatlands

NASA Astrophysics Data System (ADS)

Richardson, C. J.; Flanagan, N. E.; Wang, H.; Ho, M.; Hodgkins, S. B.; Cooper, W. T.; Chanton, J.; Winton, S.

2017-12-01

The mechanisms regulating peat decomposition and C carbon storage in peatlands are poorly understood, particularly with regard to the importance of the biochemical compounds produced by different plant species and in turn peat quality controls on C storage and GHG flux. To examine the role of carbon quality in C accretion in northern compared to tropical peatlands we completed field and lab studies on bog peats collected in Minnesota, North Carolina, Florida and Peru to answer three fundamental questions; 1) is tropical peat more recalcitrant than northern peat 2) does the addition of aromatic and phenolic C compounds increase towards the tropics 3) do differences in the chemical structure of organic matter explain variances in carbon storage and GHG flux in tropical versus northern peatlands? Our main hypothesize is that high concentrations of phenolics and aromatic C compounds produced in shrub and tree plant communities in peatlands coupled with the fire production of biochar aromatics in peatlands may provide a dual biogeochemical latch mechanism controlling microbial decomposition of peat even under higher temperatures and seasonal drought. By comparing the peat bog soil cores collected from the MN peat bogs, NC Pocosins, FL Everglades and Peru palm swamps we find that the soils in the shrub-dominant Pocosin contain the highest phenolics, which microbial studies indicate have the strongest resistance to microbial decomposition. A chemical comparison of plant driven peat carbon quality along a north to south latitudinal gradient indicates that tropical peatlands have higher aromatic compounds, and enhanced phenolics, especially after light fires, which enhances C storage and affect GHG flux across the latitudinal gradient.

Spatial variation of peat soil properties in the oil-producing region of northeastern Sakhalin

NASA Astrophysics Data System (ADS)

Lipatov, D. N.; Shcheglov, A. I.; Manakhov, D. V.; Zavgorodnyaya, Yu. A.; Rozanova, M. S.; Brekhov, P. T.

2017-07-01

Morphology and properties of medium-deep oligotrophic peat, oligotrophic peat gley, pyrogenic oligotrophic peat gley, and peat gley soils on subshrub-cotton grass-sphagnum bogs and in swampy larch forests of northeastern Sakhalin have been studied. Variation in the thickness and reserves of litters in the studied bog and forest biogeocenoses has been analyzed. The profile distribution and spatial variability of moisture, density, ash, and pHKCl in separate groups of peat soils have been described. The content and spatial variability of petroleum hydrocarbons have been considered in relation to the accumulation of natural bitumoids by peat soils and the technogenic pressing in the oil-producing region. Variation of each parameter at different distances (10, 50, and 1000 m) has been estimated using a hierarchical sampling scheme. The spatial conjugation of soil parameters has been studied by factor analysis using the principal components method and Spearman correlation coefficients. Regression equations have been proposed to describe relationships of ash content with soil density and content of petroleum hydrocarbons in peat horizons.

Distribution and speciation of mercury in the peat bog of Xiaoxing'an Mountain, northeastern China.

PubMed

Liu, Ruhai; Wang, Qichao; Lu, Xianguo; Fang, Fengman; Wang, Yan

2003-01-01

Most reports on mercury (Hg) in boreal ecosystems are from the Nordic countries and North America. Comparatively little information is available on Hg in wetlands in China. We present here a study on Hg in the Tangwang River forested catchment of the Xiaoxing'an Mountain in the northeast of China. The average total Hg (THg) in peat profile ranged from 65.8 to 186.6 ng g(-1) dry wt with the highest at the depth of 5-10 cm. THg in the peat surface was higher than the background in Heilongjiang province, the Florida Everglades, and Birkeness in Sweden. MethylHg (MeHg) concentration ranged from 0.16 to 1.86 ng g(-1) dry wt, with the highest amount at 10-15 cm depth. MeHg content was 0.2-1.2% of THg. THg and MeHg all decreased with the depth. THg in upland layer of soil (0-20 cm) was comparable to the peat surface, but in deeper layers THg concentration in peat was much higher than that in the forested mineral soil. THg in the peat bog increased, but MeHg decreased after it was drained. THg content in plant was different; THg contents in moss (119 ng g(-1) dry wt, n=12) were much higher than in the herbage, the arbor, and the shrubs. The peat bog has mainly been contaminated by Hg deposition from the atmosphere.

Specific features of the development of soils of hydromorphic ecosystems in the northern taiga of Western Siberia under conditions of cryogenesis

NASA Astrophysics Data System (ADS)

Matyshak, G. V.; Bogatyrev, L. G.; Goncharova, O. Yu.; Bobrik, A. A.

2017-10-01

Differently directed and heterochronous cryogenic processes have contributed to the contrasting soil cover patterns and spatial heterogeneity of the properties of soils in hydromorphic ecosystems of the discontinuous permafrost zone of the northern taiga in Western Siberia. Frost heave and permafrost thawing within ecosystems of highmoor bogs have led to the development of specific cryogenic landforms, such as flat-topped and large peat mounds. A set of cryogenic soils is developed in these ecosystems; it includes different variants of cryozems, gleyzems (Cryosols), and peat soils (Histosols). The distribution of these soil types is controlled by the local topography and thawing depth, other factors being insignificant. Alternation of peat horizons of different types and ages, whirl-like patterns of horizon boundaries, considerable variations in the thickness of soil horizons, and inversions of soil horizons under the impact of frost cracking, frost heave, and cryoturbation are typical of the considered soils. Thawing depth is the most significant factor affecting the thickness of organic horizons, the soil pH, and the degree of decomposition of peat. As a result of the upward movement of bog ecosystems under the impact of frost heave, peat soils are subjected to considerable transformation: peat horizons undergo mineralization, and the thickness of organic horizons decreases; in some cases, eluvial-illuvial differentiation of the mineral horizons takes place, and peat podzols are developed. However, the opposite process of the return of the soils to the bog stage of pedogenesis with peat accumulation may take place in any time in the case of activation of thermokarst processes.

Vertical Stratification of Peat Pore Water Dissolved Organic Matter Composition in a Peat Bog in Northern Minnesota: Pore Water DOM composition in a peat bog

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tfaily, Malak M.; Wilson, Rachel M.; Cooper, William T.

We characterized dissolved organic matter (DOM) composition throughout the peat column at the Marcell S1 forested bog in northern Minnesota and tested the hypothesis that redox oscillations associated with cycles of wetting and drying at the surface of the fluctuating water table correlate with increased carbon, sulfur and nitrogen turn over. We found significant vertical stratification of DOM molecular composition and EEM-PARAFAC components within the peat column. In particular the intermediate depth zone (~ 50 cm) was identified as a zone where maximum decomposition and turnover is taking place. Surface DOM was dominated by inputs from surface vegetation. The intermediate-depthmore » zone was an area of high organic matter reactivity and increased microbial activity with diagenetic formation of many unique compounds, among them polycyclic aromatic compounds (PAC) that contain both nitrogen and sulfur heteroatoms. These compounds have been previously observed in coal-derived compounds and were assumed to be responsible for coal's biological activity. Biological processes triggered by redox oscillations taking place at the intermediate depth zone of the peat profile at the S1 bog are assumed to be responsible for the formation of these heteroatomic PACs in this system. Alternatively these compounds could stem from black carbon and nitrogen derived from fires that have occurred at the site in the past. Surface and deep DOM exhibited more similar characteristics, compared to the intermediate-depth zone, with the deep layer exhibiting greater input of microbially degraded organic matter than the surface suggesting that the entire peat profile consists of similar parent material at different degrees of decomposition and that lateral and vertical advection of pore water from the surface to the deeper horizons is responsible for such similarities. Our findings suggest that molecular composition of DOM in peatland pore water is dynamic and is a function of ecosystem activity, water table and redox oscillation and porewater advection.« less

Peatlands and green frogs: A relationship regulated by acidity?

USGS Publications Warehouse

Mazerolle, M.J.

2005-01-01

The effects of site acidification on amphibian populations have been thoroughly addressed in the last decades. However, amphibians in naturally acidic environments, such as peatlands facing pressure from the peat mining industry, have received little attention. Through two field studies and an experiment, I assessed the use of bog habitats by the green frog (Rana clamitans melanota), a species sensitive to various forestry and peat mining disturbances. First, I compared the occurrence and breeding patterns of frogs in bog and upland ponds. I then evaluated frog movements between forest and bog habitats to determine whether they corresponded to breeding or postbreeding movements. Finally, I investigated, through a field experiment, the value of bogs as rehydrating areas for amphibians by offering living Sphagnum moss and two media associated with uplands (i.e., water with pH ca 6.5 and water-saturated soil) to acutely dehydrated frogs. Green frog reproduction at bog ponds was a rare event, and no net movements occurred between forest and bog habitats. However, acutely dehydrated frogs did not avoid Sphagnum. Results show that although green frogs rarely breed in bogs and do not move en masse between forest and bog habitats, they do not avoid bog substrates for rehydrating, despite their acidity. Thus, bogs offer viable summering habitat to amphibians, which highlights the value of these threatened environments in terrestrial amphibian ecology.

Dynamics of biochemical processes and redox conditions in geochemically linked landscapes of oligotrophic bogs

NASA Astrophysics Data System (ADS)

Inisheva, L. I.; Szajdak, L.; Sergeeva, M. A.

2016-04-01

The biological activity in oligotrophic peatlands at the margins of the Vasyugan Mire has been studied. It is shown found that differently directed biochemical processes manifest themselves in the entire peat profile down to the underlying mineral substrate. Their activity is highly variable. It is argued that the notion about active and inert layers in peat soils is only applicable for the description of their water regime. The degree of the biochemical activity is specified by the physical soil properties. As a result of the biochemical processes, a micromosaic aerobic-anaerobic medium is developed under the surface waterlogged layer of peat deposits. This layer contains the gas phase, including oxygen. It is concluded that the organic and mineral parts of peat bogs represent a single functional system of a genetic peat profile with a clear record of the history of its development.

Radiometric age dating of peat cores from ombrotrophic bogs: challenges and opportunities presented by the Industrial Period

NASA Astrophysics Data System (ADS)

Shotyk, W.; Appleby, P.; Davies, L. J.; Froese, D. G.; Magnan, G.; Mullan-Boudreau, G.; Noernberg, T.; Bob, S.; van Bellen, S.; Zaccone, C.

2016-12-01

The upper layers of ombrotrophic (rain-fed) bogs are hydrologically isolated from surface waters and groundwaters and, in consequence, contaminants are supplied exclusively from the atmosphere. Peat cores from bogs have been used to reconstruct the history of heavy metal pollution since mining and metallurgy began, but the greatest changes have taken place since the start of the Industrial Revolution which was well underway by the middle of the 19th century. Dating peat, accumulated since this time has been made possible using 210Pb (t1/2 = 22.3 yr), but the validity of the age-depth relationship obtained must always be assessed using one or more chronostratigraphic markers. The post-industrial period provides an enormous range of possible time markers including various fallout radionuclides, numerous trace metals and their isotopes, and countless organic contaminants. Most of these have not yet been explored, and will be helpful only if they are immobile in the peat column; often, their fate during chemical diagenesis in anoxic, acidic bog waters is either unknown or at least poorly understood. The atmospheric bomb pulse curve of 14C for the period since AD 1950 has proved to be particularly valuable for validating 210Pb chronologies by providing accurate dates for individual plant macrofossils. Peat cores collected in northern Alberta, surrounding open pit mines and upgraders of Athabsca Bituminous Sands, were carefully dated using 210Pb and the age-depth relationship evaluated using both 241Am and 14C. The cores nearest industry (MIL, JPH4) show that atmospheric deposition of trace metals has been declining ever since industrial-scale mining and refining began in 1967. This includes all of the potentially toxic trace elements (Ag, Cd, Pb, Sb, Tl), but also the metals known for their enrichment in bitumen (V, Ni, Mo). In fact, the surface layers of these bogs today are comparable in composition to the "cleanest" peat samples ever found in the northern hemisphere. Our findings are completely opposed to recent claims about environmental pollution by metals from mining and upgrading in this region, illustrating the importance of reliable age dates and the value of robust age-depth models.

Interactions between Nitrogen Fixation and Methane Cycling in Northern Minnesota Peat Bogs

NASA Astrophysics Data System (ADS)

Warren, M. J.; Gaby, J. C.; Lin, X.; Morton, P. L.; Kostka, J. E.; Glass, J. B.

2014-12-01

Peatlands cover only 3% of the Earth's surface, yet store a third of soil carbon. Increasing global temperatures have the potential to change peatlands from a net sink to a net source of atmospheric carbon. N is a limiting nutrient in oligotrophic Sphagnum-dominated peatlands and biological N2 fixation likely supplies a significant but unknown fraction of N inputs. Moreover, environmental controls on diazotrophic community composition in N-limited peatlands are poorly constrained. Thus, improved understanding of feedbacks between the CH4 and N cycles is critical for predicting future changes to CH4 flux from peat bogs. We coupled measurements of N2 fixation activity measured by the acetylene (C2H2) reduction assay (ARA) with molecular analyses of expression and diversity of nifH genes encoding the molybdenum (Mo)-containing nitrogenase from two peat bogs in the Marcell Experimental Forest, Minnesota, USA. The top 10 cm of peat was sampled from the high CH4 flux S1 bog and the low CH4 flux Zim bog in April and June 2014. Despite similar N concentrations in the top 10 cm of both bogs (0.5-1.0 μM NO2-+NO3- and 2-3 μM NH4+), the S1 bog displayed variable ARA activity (1-100 nmol C2H4 h-1 g-1) whereas the Zim bog had consistently low ARA activity (<1 nmol C2H4 h-1 g-1). Highest ARA activity was measured in June from S1 bog hollows with higher moisture content incubated without O2 in the light (20-100 nmol C2H4 h-1 g-1). Dissolved Fe (1-25 μM) was higher in hollow vs. hummock samples, and at S1 vs. Zim bog, while dissolved V (4-14 nM) was consistently higher than Mo (1-4 nM), suggesting that alternative V or Fe-containing nitrogenases might be present in these bogs. In contrast, Cu, an essential micronutrient for aerobic methanotrophs, was higher in hummocks (25-48 nM) than hollows (6-17 nM). The facultative methanotroph Methylocella was the dominant diazotroph in the S1 bog based on high throughput next generation sequencing of nifH cDNA amplicons. Given previous reports of C2H2 inhibition of methanotrophy, we measured CH4 consumption in the presence or absence of 1% C2H2. Preliminary results suggest minimal effect of C2H2 on CH4 oxidation. Future measurements of 15N2 incorporation coupled to molecular analysis will elucidate whether methanotroph diazotrophy was suppressed by C2H2 in ARA incubations.

Historical peat loss explains limited short-term response of drained blanket bogs to rewetting.

PubMed

Williamson, Jennifer; Rowe, Edwin; Reed, David; Ruffino, Lucia; Jones, Peter; Dolan, Rachel; Buckingham, Helen; Norris, David; Astbury, Shaun; Evans, Chris D

2017-03-01

This study assessed the short-term impacts of ditch blocking on water table depth and vegetation community structure in a historically drained blanket bog. A chronosequence approach was used to compare vegetation near ditches blocked 5 years, 4 years and 1 year prior to the study with vegetation near unblocked ditches. Plots adjacent to and 3 m away from 70 ditches within an area of blanket bog were assessed for floristic composition, aeration depth using steel bars, and topography using LiDAR data. No changes in aeration depth or vegetation parameters were detected as a function of ditch-blocking, time since blocking, or distance from the ditch, with the exception of non-Sphagnum bryophytes which had lower cover in quadrats adjacent to ditches that had been blocked for 5 years. Analysis of LiDAR data and the observed proximity of the water table to the peat surface led us to conclude that the subdued ecosystem responses to ditch-blocking were the result of historical peat subsidence within a 4-5 m zone either side of each ditch, which had effectively lowered the peat surface to the new, ditch-influenced water table. We estimate that this process led to the loss of around 500,000 m 3 peat within the 38 km 2 study area following drainage, due to a combination of oxidation and compaction. Assuming that 50% of the volume loss was due to oxidation, this amounts to a carbon loss of 11,000 Mg C over this area, i.e. 3 Mg C ha -1 . The apparent 'self-rewetting' of blanket bogs in the decades following drainage has implications for their restoration as it suggests that there may not be large quantities of dry peat left to rewet, and that there is a risk of inundation (potentially leading to high methane emissions) along subsided ditch lines. Many peatland processes are likely to be maintained in drained blanket bog, including support of typical peatland vegetation, but infilling of lost peat and recovery of original C stocks are likely to take longer than is generally anticipated. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Peat Depth Assessment Using Airborne Geophysical Data for Carbon Stock Modelling

NASA Astrophysics Data System (ADS)

Keaney, Antoinette; McKinley, Jennifer; Ruffell, Alastair; Robinson, Martin; Graham, Conor; Hodgson, Jim; Desissa, Mohammednur

2013-04-01

The Kyoto Agreement demands that all signatory countries have an inventory of their carbon stock, plus possible future changes to this store. This is particularly important for Ireland, where some 16% of the surface is covered by peat bog. Estimates of soil carbon stores are a key component of the required annual returns made by the Irish and UK governments to the Intergovernmental Panel on Climate Change. Saturated peat attenuates gamma-radiation from underlying rocks. This effect can be used to estimate the thickness of peat, within certain limits. This project examines this relationship between peat depth and gamma-radiation using airborne geophysical data generated by the Tellus Survey and newly acquired data collected as part of the EU-funded Tellus Border project, together encompassing Northern Ireland and the border area of the Republic of Ireland. Selected peat bog sites are used to ground truth and evaluate the use of airborne geophysical (radiometric and electromagnetic) data and validate modelled estimates of soil carbon, peat volume and depth to bedrock. Data from two test line sites are presented: one in Bundoran, County Donegal and a second line in Sliabh Beagh, County Monaghan. The plane flew over these areas at different times of the year and at a series of different elevations allowing the data to be assessed temporally with different soil/peat saturation levels. On the ground these flight test lines cover varying surface land use zones allowing future extrapolation of data from the sites. This research applies spatial statistical techniques, including uncertainty estimation in geostatistical prediction and simulation, to investigate and model the use of airborne geophysical data to examine the relationship between reduced radioactivity and peat depth. Ground truthing at test line locations and selected peat bog sites involves use of ground penetrating radar, terrestrial LiDAR, peat depth probing, magnetometry, resistivity, handheld gamma-ray spectrometry, moisture content and rainfall monitoring combined with a real-time Differential Global Positioning System (DGPS) to monitor temporal and spatial variability of bog elevations. This research will assist in determining the accuracy and limitations of modelling soil carbon and changes in peat stocks by investigating the attenuation of gamma-radiation from underlying rocks. Tellus Border is supported by the EU INTERREG IVA programme, which is managed by the Special EU Programmes Body in Northern Ireland, the border Region of Ireland and western Scotland. The Tellus project was funded by the Northern Ireland Development of Enterprise Trade and Investment and by the Rural Development Programme through the Northern Ireland Programme for Building Sustainable Prosperity.

The paleoecology, peat chemistry and carbon storage of a discontinuous permafrost peatland

NASA Astrophysics Data System (ADS)

Talbot, Julie; Pelletier, Nicolas; Olefeldt, David; Turetsky, Merritt; Blodau, Christian; Sonnentag, Oliver; Quinton, William

2017-04-01

Permafrost in peatlands strongly influences ecosystem biogeochemical functioning, vegetation composition and hydrological functions. Permafrost peatlands of northwestern Canada store large amounts of carbon but the peatlands located at the southern margin of the permafrost zone are thawing rapidly. This thaw triggers changes in vegetation, hydrology and peat characteristics, and may affect carbon stocks. We present data from a permafrost plateau to thermokarst bog chronosequence located in the southern portion of the Scotty Creek watershed near Fort Simpson, Northwest Territories, Canada. We assessed changes in plant communities, hydrology, biogeochemistry and permafrost status over 9000 years of peatland development using plant macrofossil, testate amoeba and peat chemical characteristics. Peat accumulation started after the infilling of a lake 8500 cal. yr BP. Minerotrophic peat prevailed at the site until permafrost formed around 5000 cal. yr BP. Permafrost apparently formed three times, although there is spatial variability in the permafrost aggradation - degradation cycles. Permafrost thawed 550 cal. yr BP in the center of the thermokarst bog. Ombrotrophic peat is a fairly recent feature of the peat profiles, only appearing after the most recent permafrost thaw event. Both allogenic (temperature/precipitation/snow cover changes and wildfire) and autogenic (peat accumulation, Sphagnum growth) processes likely influenced permafrost aggradation and thaw. While apparent carbon accumulation rates were lower during present and past permafrost periods than during non-permafrost periods, long term carbon accumulation remained similar between cores with different permafrost period lengths. Deep peat was more decomposed in the thermokarst bog peat profile than in the permafrost plateau profile, highlighting the importance of considering potential deep peat carbon losses to project the fate of thawing permafrost peat carbon stores. Average long-term carbon accumulation derived from the peat cores (n=3, 20.6 ± 1.9 g C m-2 a-1) is in the same range than the contemporary landscape-scale carbon balance measured from eddy covariance at the site ( 15 g C m-2 a-1). While the carbon to nitrogen ratio tends to decrease with peat depth, the carbon to phosphorus ratio tends to increase, perhaps indicating a preferential uptake of phosphorus over nitrogen by plants.

The Paradox of Excess Nitrogen in Boreal Peatlands: Biogeochemical Gaps in Nitrogen Cycling Revealed

NASA Astrophysics Data System (ADS)

Vile, M. A.; Prsa, T.; Wieder, R.; Lamers, L. P.

2011-12-01

Globally, peatlands cover 3-4 % of the Earth's land surface (over 4 million km 2, yet they store 25-30 % of the world's soil carbon (C) and 9-16% of the world's soil nitrogen (N, 8-15 Pg) in peat. As in other terrestrial ecosystems, the cycling of C and N is closely linked, especially for ombrotrophic bogs. Bogs receive nutrient and water exclusively from the atmosphere, which ensures an N-limited, nutrient-poor habitat. In Alberta, NW Canada, peatlands have received exceptionally low atmospheric inputs of N (< 1 7 kg/ha/yr) from their first introduction on the landscape ~ 7000 yrs bp, up to the present time. Paradoxically, despite these low inputs of atmospheric N deposition, bases on 210-fixation Pb dating of peat cores, we have shown that over the past 50 years these bogs have accumulated approximately 11-21 times more N in peat than can be explained by inputs of atmospheric N. A likely missing input is N2-fixation from cyanobacteria associated with Sphagnum mosses, however this process has been largely overlooked in boreal peatlands. Here we demonstrate the importance of N2-fixation in explaining the high accumulation rates of N found in unpolluted, boreal bogs of western Canada. Calibrated (using theoretical ratio of 1.5-3:1) rates of N2-fixation for 4 bogs in northern Alberta ranged from 1.6 to 8.0 ± 0.7 kg/ha/yr, indicating that 42-58 % of the N accumulated over in peat, can be attributed to biological N2-fixation. Although most of northern Alberta's peatlands continue to receive exceptionally low atmospheric N deposition rates, over the last 3 decades, rapid development and industrial expansion of Alberta's Oil Sands Mining (OSM) potentially threaten the pristine nature of peatlands through regionally elevated deposition of N-compounds (NOx). Prior to OSM, N inputs to bogs were limited exclusively to (1) biological N fixation, and (2) bulk background deposition. We examined the response of peatlands located in the OSM area to enhanced N deposition. Despite the large accumulation rates of N in peat, mean N:P ratios in Sphagnum moss capitula (11.0 ± 3.4; mean ± stdev) suggest that peat of boreal western Canada is still severely N limited and not limited by phosphorus. Collectively, these data underscore the severity of N-limitation in pristine bogs and their potential sensitivity to increased N inputs from oils sands mining. Additionally, because the majority of the data generated for N stress in peatlands is from eastern Canada and western Europe, we stress the need to encompass the response of bogs to N deposition within the bounds of the low N deposition gradient. We postulate the loss of symbiosis between Sphagnum and N-fixing microorganisms (cyanobacteria, bacteria) in nitrogen-polluted areas, and indicate its consequences at the species level (trade-off) and ecosystem level (including C sequestration).

Animal and vegetation patterns in natural and man-made bog pools: implications for restoration

USGS Publications Warehouse

Mazerolle, M.J.; Poulin, M.; Lavoie, C.; Rochefort, L.; Desrochers, A.; Drolet, B.

2006-01-01

1. Peatlands have suffered great losses following drainage for agriculture, forestry, urbanisation, or peat mining, near inhabited areas. We evaluated the faunal and vegetation patterns after restoration of a peatland formerly mined for peat. We assessed whether bog pools created during restoration are similar to natural bog pools in terms of water chemistry, vegetation structure and composition, as well as amphibian and arthropod occurrence patterns. 2. Both avian species richness and peatland vegetation cover at the site increased following restoration. Within bog pools, however, the vegetation composition differed between natural and man-made pools. The cover of low shrubs, Sphagnum moss, submerged, emergent and floating vegetation in man-made pools was lower than in natural pools, whereas pH was higher than in typical bog pools. Dominant plant species also differed between man-made and natural pools. 3. Amphibian tadpoles, juveniles and adults occurred more often in man-made pools than natural bog pools. Although some arthropods, including Coleoptera bog specialists, readily colonised the pools, their abundance was two to 26 times lower than in natural bog pools. Plant introduction in bog pools, at the stocking densities we applied, had no effect on the occurrence of most groups. 4. We conclude that our restoration efforts were partially successful. Peatland-wide vegetation patterns following restoration mimicked those of natural peatlands, but 4 years were not sufficient for man-made pools to fully emulate the characteristics of natural bog pools.

SPRUCE Peat Physical and Chemical Characteristics from Experimental Plot Cores, 2012

DOE Data Explorer

Iversen, C. M. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hanson, P. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Brice, D. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Phillips, J. R. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; McFarlane, K. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hobbie, E. A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Kolka, R. K. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.

2012-01-01

This data set reports the results of physical and chemical analyses of peat core samples from the SPRUCE experimental study plots located in the S1-Bog. On August 13-15, 2012, a team of SPRUCE investigators and collaborators collected core samples of peat in the SPRUCE experimental plots. The goal was to characterize the biological, physical, and chemical characteristics of peat, and how those characteristics changed throughout the depth profile of the bog, prior to the initialization of the SPRUCE experimental warming and CO2 treatments. Cores were collected from 16 experimental plots; samples were collected from the hummock and hollow surfaces to depths of 200-300 cm in defined increments. Three replicate cores were collected from both hummock and hollow locations in each plot. The coring locations within each plot were mapped

The structure of the microbial communities in low-moor and high-moor peat bogs of Tomsk oblast

NASA Astrophysics Data System (ADS)

Dobrovol'skaya, T. G.; Golovchenko, A. V.; Kukharenko, O. S.; Yakushev, A. V.; Semenova, T. A.; Inisheva, L. A.

2012-03-01

The number, structure, and physical state of the microbial communities in high-moor and low-moor peat bogs were compared. Distinct differences in these characteristics were revealed. The microbial biomass in the high-moor peat exceeded that in the low-moor peat by 2-9 times. Fungi predominated in the high-moor peat, whereas bacteria were the dominant microorganisms in the low-moor peat. The micromycetal complexes of the high-moor peat were characterized by a high portion of dark-colored representatives; the complexes of the low-moor peat were dominated by fast-growing fungi. The species of the Penicillum genus were dominant in the high-moor peat; the species of Trichoderma were abundant in the low-moor peat. In the former, the bacteria were distinguished as minor components; in the latter, they predominated in the saprotrophic bacterial complex. In the high-moor peat, the microorganisms were represented by bacilli, while, in the low-moor peat, by cytophages, myxobacteria, and actinobacteria. The different physiological states of the bacteria in the studied objects reflecting the duration of the lag phase and the readiness of the metabolic system to consume different substrates were demonstrated for the first time. The relationships between the trophic characteristics of bacterial habitats and the capacity of the bacteria to consume substrates were established.

Preliminary stable isotope results from the Mohos peat bog, East-Carpathians

NASA Astrophysics Data System (ADS)

Túri, Marianna; Palcsu, László; Futó, István; Hubay, Katalin; Molnár, Mihály; Rinyu, László; Braun, Mihály

2016-04-01

This work provides preliminary results of an isotope investigation carried out on a peat core drilled in the ombrotrophic Mohos peat bog, Ciomadul Mountain, (46°8'3.60"N, 25°54'19.43"E, 1050 m.a.s.l.), East Carpathians, Romania. The Ciomadul is a single dacitic volcano with two craters: the younger Saint Ana and the older Mohos which is a peat bog, and surrounded by a number of individual lava domes as well as a narrow volcaniclastic ring plain volcano. A 10 m long peat core has been taken previously, and is available for stable oxygen and carbon isotope analysis. It is known from our previous work (Hubay et al., 2015) that it covers a period from 11.500 cal year B.P. to present. The peat bog is composed mainly of Sphagnum, which has a direct relationship with the environment, making it suitable for examine the changes in the surrounding circumstances. Isotopic analysis of the prepared cellulose from Sphagnum moss has the attribute to provide such high resolution quantitative estimates of the past climate and there is no such climate studies in this area where the past climate investigations based on oxygen isotope analysis of the Sphagnum. Oxygen and carbon stable isotope analysis were carried out on the hemicellulose samples, which were chemically prepared for 14C dating and taken from every 30 cm of the 10 m long peat core. The oxygen isotope composition of the precipitation can be revealed from the δ18O values of the prepared cellulose samples, since, while carbon isotope ratio tells more about the wet and dry periods of the past. Studying both oxygen and carbon isotope signatures, slight fluctuations can be seen during the Holocene like some of the six periods of significant climate changes can be seen in this resolution during the time periods of 9000-8000, 6000-5000, 4200-3800, 3500-2500, 1200-1000, and 600-150 cal yr B.P. Additionally, the late Pleistocene - early Holocene environmental changes can be clearly observed as Pleistocene peat samples have increasingly negative delta values as going back in time. All measurements were carried out in Hertelendi Laboratory of Environmental Studies, Institute for Nuclear Research, Hungarian Academy of Sciences. Katalin Hubay, Mihály Braun, Sándor Harangi, László Palcsu, Marianna Túri, László Rinyu, Mihály Molnár, 2015. European Geosciences Union (EGU) General Assembly 2015, Radiocarbon dating of Sphagnum cellulose from Mohos peat bog, East Carpathians, accepted in CL5.10/GM1.10 Geophysical Research Abstracts Vol. 17, EGU2015-10813, 2015

High nitrogen availability reduces polyphenol content in Sphagnum peat.

PubMed

Bragazza, Luca; Freeman, Chris

2007-05-15

Peat mosses of the genus Sphagnum constitute the bulk of living and dead biomass in bogs. These plants contain peculiar polyphenols which hamper litter peat decomposition through their inhibitory activity on microbial breakdown. In the light of the increasing availability of biologically active nitrogen in natural ecosystems, litter derived from Sphagnum mosses is an ideal substrate to test the potential effects of increased atmospheric nitrogen deposition on polyphenol content in litter peat. To this aim, we measured total nitrogen and soluble polyphenol concentration in Sphagnum litter peat collected in 11 European bogs under a chronic gradient of atmospheric nitrogen deposition. Our results demonstrate that increasing nitrogen concentration in Sphagnum litter, as a consequence of increased exogenous nitrogen availability, is accompanied by a decreasing concentration of polyphenols. This inverse relationship is consistent with reports that in Sphagnum mosses, polyphenol and protein biosynthesis compete for the same precursor. Our observation of modified Sphagnum litter chemistry under chronic nitrogen eutrophication has implications in the context of the global carbon balance, because a lower content of decay-inhibiting polyphenols would accelerate litter peat decomposition.

Vertical Stratification of Peat Pore Water Dissolved Organic Matter Composition in a Peat Bog in Northern Minnesota: Pore Water DOM composition in a peat bog

DOE PAGES

Tfaily, Malak M.; Wilson, Rachel M.; Cooper, William T.; ...

2018-01-29

Here, we characterized dissolved organic matter (DOM) composition throughout the peat column at the Marcell S1 forested bog in northern Minnesota and tested the hypothesis that redox oscillations associated with cycles of wetting and drying at the surface of the fluctuating water table correlate with increased carbon, sulfur, and nitrogen turn over. We found significant vertical stratification of DOM molecular composition and excitation-emission matrix parallel factor analysis components within the peat column. In particular, the intermediate depth zone (~ 50 cm) was identified as a zone where maximum decomposition and turnover is taking place. Surface DOM was dominated by inputsmore » from surface vegetation. The intermediate depth zone was an area of high organic matter reactivity and increased microbial activity with diagenetic formation of many unique compounds, among them polycyclic aromatic compounds that contain both nitrogen and sulfur heteroatoms. These compounds have been previously observed in coal-derived compounds and were assumed to be responsible for coal's biological activity. Biological processes triggered by redox oscillations taking place at the intermediate depth zone of the peat profile at the S1 bog are assumed to be responsible for the formation of these heteroatomic PACs in this system. Alternatively, these compounds could stem from black carbon and nitrogen derived from fires that have occurred at the site in the past. Surface and deep DOM exhibited more similar characteristics, compared to the intermediate depth zone, with the deep layer exhibiting greater input of microbially degraded organic matter than the surface suggesting that the entire peat profile consists of similar parent material at different degrees of decomposition and that lateral and vertical advection of pore water from the surface to the deeper horizons is responsible for such similarities. Lastly, our findings suggest that molecular composition of DOM in peatland pore water is dynamic and is a function of ecosystem activity, water table, redox oscillation, and pore water advection.« less

Vertical Stratification of Peat Pore Water Dissolved Organic Matter Composition in a Peat Bog in Northern Minnesota: Pore Water DOM composition in a peat bog

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tfaily, Malak M.; Wilson, Rachel M.; Cooper, William T.

Here, we characterized dissolved organic matter (DOM) composition throughout the peat column at the Marcell S1 forested bog in northern Minnesota and tested the hypothesis that redox oscillations associated with cycles of wetting and drying at the surface of the fluctuating water table correlate with increased carbon, sulfur, and nitrogen turn over. We found significant vertical stratification of DOM molecular composition and excitation-emission matrix parallel factor analysis components within the peat column. In particular, the intermediate depth zone (~ 50 cm) was identified as a zone where maximum decomposition and turnover is taking place. Surface DOM was dominated by inputsmore » from surface vegetation. The intermediate depth zone was an area of high organic matter reactivity and increased microbial activity with diagenetic formation of many unique compounds, among them polycyclic aromatic compounds that contain both nitrogen and sulfur heteroatoms. These compounds have been previously observed in coal-derived compounds and were assumed to be responsible for coal's biological activity. Biological processes triggered by redox oscillations taking place at the intermediate depth zone of the peat profile at the S1 bog are assumed to be responsible for the formation of these heteroatomic PACs in this system. Alternatively, these compounds could stem from black carbon and nitrogen derived from fires that have occurred at the site in the past. Surface and deep DOM exhibited more similar characteristics, compared to the intermediate depth zone, with the deep layer exhibiting greater input of microbially degraded organic matter than the surface suggesting that the entire peat profile consists of similar parent material at different degrees of decomposition and that lateral and vertical advection of pore water from the surface to the deeper horizons is responsible for such similarities. Lastly, our findings suggest that molecular composition of DOM in peatland pore water is dynamic and is a function of ecosystem activity, water table, redox oscillation, and pore water advection.« less

Soil data for a collapse-scar bog chronosequence in Koyukuk Flats National Wildlife Refuge, Alaska, 2008

USGS Publications Warehouse

O’Donnell, Jonathan A.; Harden, Jennifer W.; Manies, Kristen L.; Jorgenson, M. Torre

2012-01-01

Peatlands in the northern permafrost region store large amounts of organic carbon, most of which is currently stored in frozen peat deposits. Recent warming at high-latitudes has accelerated permafrost thaw in peatlands, which will likely result in the loss of soil organic carbon from previously frozen peat deposits to the atmosphere. Here, we report soil organic carbon inventories, soil physical data, and field descriptions from a collapse-scar bog chronosequence located in a peatland ecosystem at Koyukuk Flats National Wildlife Refuge in Alaska.

Isotopic evidence for nitrogen mobility in peat bogs

NASA Astrophysics Data System (ADS)

Novak, Martin; Stepanova, Marketa; Jackova, Ivana; Vile, Melanie A.; Wieder, R. Kelman; Buzek, Frantisek; Adamova, Marie; Erbanova, Lucie; Fottova, Daniela; Komarek, Arnost

2014-05-01

Elevated nitrogen (N) input may reduce carbon (C) storage in peat. Under low atmospheric deposition, most N is bound in the moss layer. Under high N inputs, Sphagnum is not able to prevent penetration of dissolved N to deeper peat. Nitrogen may become available to the roots of invading vascular plants. The concurrent oxygenation of deeper peat layers, along with higher supply of labile organic C, may enhance microbial decomposition and lead to peat thinning. The resulting higher emissions of greenhouse gases may accelerate global warming. Seepage of N to deeper peat has never been quantified. Here we present evidence for post-depositional mobility of atmogenic N in peat, based on natural-abundance N isotope ratios. We conducted a reciprocal peat transplant experiment between two Sphagnum-dominated peat bogs in the Czech Republic (Central Europe), differing in anthropogenic N inputs. The northern site VJ received as much as 33 kg N ha-1 yr-1 via spruce canopy throughfall. The southern site was less polluted (17.6 kg N ha-1 yr-1). Isotope signatures of living moss differed between the two sites (δ15N of -3‰ and -7‰ at VJ and CB, respectively). After 18 months, an isotope mass balance was constructed. In the CB-to-VJ transplant, a significant portion of original CB nitrogen (98-31%) was removed and replaced by nitrogen of the host site throughout the top 10 cm of the profile. Nitrogen, deposited at VJ, was immobilized in imported CB peat that was up to 20 years old. Additionally, we compared N concentration and N accumulation rates in 210Pb-dated peat profiles with well-constrained data on historical atmospheric N pollution. Nationwide N emissions peaked in 1990, while VJ exhibited the highest N content in peat that formed in 1930. This de-coupling of N inputs and N retention in peat might be interpreted as a result of translocation of dissolved pollutant N downcore, corroborating our δ15N results at VJ and CB. Data from a variety of peat bogs along pollution and climatic gradients would be needed to test to what extent the record of atmospheric N inputs in peat is overprinted by variable, locally-controlled decomposition rates.

Effect of fire on phosphorus forms in Sphagnum moss and peat soils of ombrotrophic bogs.

PubMed

Wang, Guoping; Yu, Xiaofei; Bao, Kunshan; Xing, Wei; Gao, Chuanyu; Lin, Qianxin; Lu, Xianguo

2015-01-01

The effect of burning Sphagnum moss and peat on phosphorus forms was studied with controlled combustion in the laboratory. Two fire treatments, a light fire (250 °C) and a severe fire (600 °C), were performed in a muffle furnace with 1-h residence time to simulate the effects of different forest fire conditions. The results showed that fire burning Sphagnum moss and peat soils resulted in losses of organic phosphorus (Po), while inorganic phosphorus (Pi) concentrations increased. Burning significantly changed detailed phosphorus composition and availability, with severe fires destroying over 90% of organic phosphorus and increasing the availability of inorganic P by more than twofold. Our study suggest that, while decomposition processes in ombrotrophic bogs occur very slowly, rapid changes in the form and availability of phosphorus in vegetation and litter may occur as the result of forest fires on peat soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

An ecologic study of peat landforms in Canada and Alaska

NASA Technical Reports Server (NTRS)

Glaser, P. H.

1986-01-01

The role of groundwater and surface runoff in controlling the water chemistry and development of peat landforms in northern Minnesota are described. The LANDSAT imagery taken duing spring break-up are particularly valuable in identifying potential zones of groundwater discharge. The vascular floras of raised bogs in eastern North Americas demonstrating the remarkabe uniformity of the ombrotrophic flora over broad geographic regions are described. The evolution of peat landforms in the major boreal peatlands of eastern America is examined. The LANDSAT imagery is used to determine the area of patterned to featureless peatlands, the area of ombrotrophic bog relative to minerotrophic fen, and the relative size and degree of streamlining of island landforms entirely composed of peat. Such measurements can be used to assess the role of climate, time, and hydrology in controlling the formation of peatland patterns across broad geographic regions.

Global trends in peatland methane production

NASA Astrophysics Data System (ADS)

Hoyt, A.; Corbett, J. E.; Gandois, L.; Cobb, A.; Pangala, S. R.; Gauci, V.; Harvey, C. F.

2017-12-01

Peatland methane production rates and fluxes to the atmosphere vary globally. Here we present a systematic comparison of peatland CH4 production across latitudes. We developed and applied an isotope-based mass transport model to characterize rates of methanogenesis and recharge rates across ten ombrotrophic peatlands from around the world. We validated our model against peat incubations and surface fluxes where data was available. We found striking similarities in the DIC and CH4 concentrations and δ13C isotope profiles across northern bogs, despite highly variable precipitation, recharge rates, and peat characteristics. Profiles from northern sites were similar because increased recharge rates were always compensated by increased CH4 production rates. This could represent a feedback mechanism between recharge rates and methanogenesis in northern bogs or could represent a shared dependence of these two properties on the degree of peat decomposition. We also found strong differences between northern and tropical sites, both in the rate of CH4 production, the recharge rate, and in the transport pathways and fluxes to the atmosphere. Our findings have important implications for methane transport and release to the atmosphere. In northern bogs, low flow rates allow CH4 concentrations to build up, and CH4 escapes by surface diffusion, ebullition, and plant-mediated transport. Thus, the majority of CH4 produced escapes through the peat surface. In tropical peatlands, high flow rates suppress CH4 concentrations, which do not build up above the threshold for ebullition. Instead, CH4 leaves the peat by lateral transport and surface fluxes are small. This work provides evidence that peat properties and hydrology are fundamental controls on decomposition, CH4 production, and peat formation across latitudes.

Geoinformatics meets education for a peat bog information system

NASA Astrophysics Data System (ADS)

Michel, Ulrich; Fiene, Christina; Plass, Christian

2010-10-01

Within the project "Expedition Bog: Young researchers are experimenting, exploring and discovering" a bog-information- system is developed by the Department of Geography (University of Education Heidelberg, Germany), the Institute for Geoinformatics and Remote Sensing (University of Osnabrueck, Germany; the NABU Umweltpyramide gGmbH. This information system will be available for schools and to the public. It is supplemented by teaching units on various topics around the bog via an online platform. The focus of the project, however, is the original encounter with the bog habitat. This is realized by a GPS scavenger hunt with small research tasks and observations, mapping and experiments. The project areas are the Huvenhoops bog and the Lauenbruecker bog in Rotenburg in Lower Saxony, Germany. Equipped with a researcher backpack, GPS device and a mobile bog book by means of a pocket PC, students can discover different learning stations in the project bogs. In our areas the students can learn more about different topics such as "the historical memory of the bog", "water", "peat moss and other plants" and "animals of the bog". Moreover small inquiry research projects can be executed. Experimenting on site helps students to develop important scientific findings and increases their curiosity and enthusiasm for nature. It also promotes a number of other basic skills such as literacy, language skills, social skills or fine motor skills. Moreover it also fosters the development of a positive attitude to science in general. The main objective of the project is to promote sustainable environmental education, as well as the development of environmental awareness. This will be accomplished through the imparting of knowledge but also through experiencing nature with all senses in the context of original encounters.

Late Holocene climate change in the western Mediterranean: centennial-scale vegetation and North Atlantic Oscillation variability

NASA Astrophysics Data System (ADS)

Ramos Román, M. J.; Jimenez-Moreno, G.; Anderson, R. S.; García-Alix, A.; Toney, J. L.; Jiménez-Espejo, F. J. J.; Carrión, J. S.

2015-12-01

Sediments from alpine peat bogs and lakes from the Sierra Nevada in southeastern Spain (western Mediterranean area) have been very informative in terms of how vegetation and wetland environments were impacted by past climate change. Recently, many studies try to find out the relationship between solar activity, atmosphere and ocean dynamics and changes in the terrestrial environments. The Mediterranean is a very sensitive area with respect to atmospheric dynamics due to (1) its location, right in the boundary between subtropical and temperate climate systems and (2) the North Atlantic Oscillation (NAO) is one of the main mechanism that influence present climate in this area. Here we present a multi-proxy high-resolution study from Borreguil de la Caldera (BdlC), a peat bog that records the last ca. 4500 cal yr BP of vegetation, fire, human impact and climate history from the Sierra Nevada. The pollen, charcoal and non-pollen palynomorphs (NPPs) reconstruction in the BdlC-01 record evidence relative humidity changes in the last millennia interrupting the late Holocene aridification trend. This study shows a relative arid period between ca. 4000 and 3100 cal yr BP; the Iberian Roman humid period (ca. 2600 to 1600 cal yr BP); a relative arid period during the Dark Ages (from ca. AD 500 to AD 900) and Medieval Climate Anomaly (from ca. AD 900 to ca. AD 1300) and predominantly wetter conditions corresponding with The Little Ice Age period (from ca. AD 1300 to AD 1850). This climate variability could be explained by centennial scale changes in the NAO and solar activity.

Groundwater flow with energy transport and water-ice phase change: Numerical simulations, benchmarks, and application to freezing in peat bogs

USGS Publications Warehouse

McKenzie, J.M.; Voss, C.I.; Siegel, D.I.

2007-01-01

In northern peatlands, subsurface ice formation is an important process that can control heat transport, groundwater flow, and biological activity. Temperature was measured over one and a half years in a vertical profile in the Red Lake Bog, Minnesota. To successfully simulate the transport of heat within the peat profile, the U.S. Geological Survey's SUTRA computer code was modified. The modified code simulates fully saturated, coupled porewater-energy transport, with freezing and melting porewater, and includes proportional heat capacity and thermal conductivity of water and ice, decreasing matrix permeability due to ice formation, and latent heat. The model is verified by correctly simulating the Lunardini analytical solution for ice formation in a porous medium with a mixed ice-water zone. The modified SUTRA model correctly simulates the temperature and ice distributions in the peat bog. Two possible benchmark problems for groundwater and energy transport with ice formation and melting are proposed that may be used by other researchers for code comparison. ?? 2006 Elsevier Ltd. All rights reserved.

Towards a conceptual model of hydrological change on an abandoned cutover bog, Quebec

NASA Astrophysics Data System (ADS)

van Seters, Tim E.; Price, Jonathan S.

2002-07-01

Cutover bogs do not return to functional peatland ecosystems after abandonment because re-establishment of peat-forming mosses is poor. This paper presents a conceptual model of bog disturbance caused by peat harvesting (1942-1972), and the hydrological evolution that occurred after abandonment (1973-1998). Two adjacent bogs of similar size and origin, one harvested and the other essentially undisturbed, provide the basis for understanding what changes occurred. The model is based on historical trends evident from previous surveys of land-use, bog ecology and resource mapping; and from recent hydrological and ecological data that characterize the current condition. Water balance data and historical information suggest that runoff increased and evapotranspiration decreased following drainage, but tended towards pre-disturbance levels following abandonment, as vegetation recolonized the surface and drainage became less efficient over time. Dewatering of soil pores after drainage caused shrinkage and oxidation of the peat and surface subsidence of approximately 80 cm over 57 years. Comparisons with a nearby natural bog suggest that bulk density in the upper 50 cm of cutover peat increased from 0·07 to 0·13 g cm-3, specific yield declined from 0·14 to 0·07, water table fluctuations were 67% greater, and mean saturated hydraulic conductivity declined from 4·1 × 10-5 to 1·3 × 10-5 cm s-1. More than 25 years after abandonment, Sphagnum mosses were distributed over broad areas but covered less than 15% of the surface. Areas with good Sphagnum regeneration (>10% cover) were strongly correlated with high water tables (mean -22 cm), especially in zones of seasonal groundwater discharge, artefacts of the extraction history. Forest cover expanded from 5 to 20% of the study area following abandonment. The effect of forest growth (transpiration and interception) and drainage on lowering water levels eventually will be countered by slower water movement through the increasingly dense soil, and by natural ditch deterioration. However, without management intervention, full re-establishment of natural hydrological functions will take a very long time.

Can a bog drained for forestry be a stronger carbon sink than a natural bog forest?

NASA Astrophysics Data System (ADS)

Hommeltenberg, J.; Schmid, H. P.; Drösler, M.; Werle, P.

2014-07-01

This study compares the CO2 exchange of a natural bog forest, and of a bog drained for forestry in the pre-Alpine region of southern Germany. The sites are separated by only 10 km, they share the same soil formation history and are exposed to the same climate and weather conditions. In contrast, they differ in land use history: at the Schechenfilz site a natural bog-pine forest (Pinus mugo ssp. rotundata) grows on an undisturbed, about 5 m thick peat layer; at Mooseurach a planted spruce forest (Picea abies) grows on drained and degraded peat (3.4 m). The net ecosystem exchange of CO2 (NEE) at both sites has been investigated for 2 years (July 2010-June 2012), using the eddy covariance technique. Our results indicate that the drained, forested bog at Mooseurach is a much stronger carbon dioxide sink (-130 ± 31 and -300 ± 66 g C m-2 a-1 in the first and second year, respectively) than the natural bog forest at Schechenfilz (-53 ± 28 and -73 ± 38 g C m-2 a-1). The strong net CO2 uptake can be explained by the high gross primary productivity of the 44-year old spruces that over-compensates the two-times stronger ecosystem respiration at the drained site. The larger productivity of the spruces can be clearly attributed to the larger plant area index (PAI) of the spruce site. However, even though current flux measurements indicate strong CO2 uptake of the drained spruce forest, the site is a strong net CO2 source when the whole life-cycle since forest planting is considered. It is important to access this result in terms of the long-term biome balance. To do so, we used historical data to estimate the difference between carbon fixation by the spruces and the carbon loss from the peat due to drainage since forest planting. This rough estimate indicates a strong carbon release of +134 t C ha-1 within the last 44 years. Thus, the spruces would need to grow for another 100 years at about the current rate, to compensate the potential peat loss of the former years. In contrast, the natural bog-pine ecosystem has likely been a small but stable carbon sink for decades, which our results suggest is very robust regarding short-term changes of environmental factors.

Terrain Analysis Procedural Guide for Soil. Report Number 6 in the ETL Series on Guides for Army Terrain Analysts

DTIC Science & Technology

1981-02-01

01 T3 Swamp Pt. OH. CH. MH. OL T4 Peat Bog Pt T5 . - Peat Cuttings Pt T6 Cranberry Bog Pt. OH. CH. MH, OL T7 Rice holds Pt. OH, CH, MH, OL ’ ~Known...Commonly Associated Soils Landlorm/erc Climate Horizon USCS Symbol Coastal Plain unspecified unspecified OL. ML. CL. ML-CL, MH. Depressions CH, OH...total sample. SALINA A salt marsh or pond located adjacent to the sea, but not open to the sea. SALT PAN Any flat area or natural depression where water

Identification of runoff formation with two dyes in a mid-latitude mountain headwater

NASA Astrophysics Data System (ADS)

Vlcek, Lukas; Schneider, Philipp; Falatkova, Kristyna

2017-04-01

There have been numerous studies on subsurface flow in peat bog areas, as both water scarcity and floods have led to increased attention to this specific environment and its role within the hydrological cycle. In contrast, this experimental study identifies runoff formation at two opposite hillslopes in a peaty mountain headwater; a slope with organic soils (Peat / Histosol) and shallow groundwater ( 0.5 m below surface) complemented by a slope with mineral soils (Podzol) and no detectable groundwater within 2 m below surface. Differences in infiltration, percolation, and preferential flowpaths between both hillslopes could be identified by sprinkling experiments with two dyes - Brilliant Blue FCF and Fluorescein. By excavating dye-stained soil profiles parallel ("lateral") and perpendicular ("frontal") to the slopes' gradients - both within and downstream of the sprinkling plots - dye stained flow patterns in the soil could be clearly identified. The results show that biomat flow occurred at both hillslopes. The dye solutions infiltrated into the soil and continued either as lateral subsurface pipeflow (SSF), in the case of the Peat Bog, or percolated vertically towards the bedrock in the case of the Podzol. The study provides evidence that biomat flow (BMF) - shallow, lateral preferential flowpaths along decomposed tree roots or logs - is a major runoff formation process at the Peat Bog hillslope and in the adjacent riparian zone. This lateral flow through the organic soil hillslope (Peat Bog) towards the stream occurred mainly as shallow subsurface flow in organic layers above the groundwater level (BMF and SSF), but water partly percolates to the shallow groundwater via vertical macropores as well . In contrast, the mineral soil hillslope (Podzol) was mostly dominated by vertical percolation. Lateral flow occurred only on short distances in the organic topsoil as biomat flow (BMF). The sorptive tracer Brilliant Blue FCF successfully stained flowpaths in the soil at both hillslopes, whereas the identification of soil staining patterns by the relatively conservative tracer Fluorescein was limited on organic soil profiles.

SPRUCE S1 Bog Plant-Available Nutrients Assessed with Ion-Exchange Resins from 2011-2012 in the Southern End of the S1 Bog

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iversen, C. M.; Ontl, T. A.; Brice, D. J.

This data set consists of observations of plant-available nutrients assessed using ion-exchange resin capsules incubated serially in aerobic and anaerobic peat layers beginning in 2011. Data were collected from 2011 to 2012 (prior to the construction of the SPRUCE experimental plots) at the southern end of the S1 Bog at three depths in hollow microtopography only.

Sphagnum mosses from 21 ombrotrophic bogs in the athabasca bituminous sands region show no significant atmospheric contamination of "heavy metals".

PubMed

Shotyk, William; Belland, Rene; Duke, John; Kempter, Heike; Krachler, Michael; Noernberg, Tommy; Pelletier, Rick; Vile, Melanie A; Wieder, Kelman; Zaccone, Claudio; Zhang, Shuangquan

2014-11-04

Sphagnum moss was collected from 21 ombrotrophic (rain-fed) peat bogs surrounding open pit mines and upgrading facilities of Athabasca bituminous sands in Alberta (AB). In comparison to contemporary Sphagnum moss from four bogs in rural locations of southern Germany (DE), the AB mosses yielded lower concentrations of Ag, Cd, Ni, Pb, Sb, and Tl, similar concentrations of Mo, but greater concentrations of Ba, Th, and V. Except for V, in comparison to the "cleanest", ancient peat samples ever tested from the northern hemisphere (ca. 6000-9000 years old), the concentrations of each of these metals in the AB mosses are within a factor of 3 of "natural, background" values. The concentrations of "heavy metals" in the mosses, however, are proportional to the concentration of Th (a conservative, lithophile element) and, therefore, contributed to the plants primarily in the form of mineral dust particles. Vanadium, the single most abundant trace metal in bitumen, is the only anomaly: in the AB mosses, V exceeds that of ancient peat by a factor of 6; it is therefore enriched in the mosses, relative to Th, by a factor of 2. In comparison to the surface layer of peat cores collected in recent years from across Canada, from British Columbia to New Brunswick, the Pb concentrations in the mosses from AB are far lower.

Nutrient load can lead to enhanced CH4 fluxes through changes in vegetation, peat surface elevation and water table depth in ombrotrophic bog

NASA Astrophysics Data System (ADS)

Juutinen, Sari; Bubier, Jill; Larmola, Tuula; Humphreys, Elyn; Arnkil, Sini; Roy, Cameron; Moore, Tim

2016-04-01

Atmospheric nitrogen (N) deposition has led to nutrient enrichment in wetlands, particularly in temperate areas, affecting plant community composition, carbon (C) cycling, and microbial dynamics. It is vital to understand the temporal scales and mechanisms of the changes, because peatlands are long-term sinks of C, but sources of methane (CH4), an important greenhouse gas. Rainwater fed (ombrotrophic) bogs are considered to be vulnerable to nutrient loading due to their natural nutrient poor status. We fertilized Mer Bleue Bog, a Sphagnum moss and evergreen shrub-dominated ombrotrophic bog near Ottawa, Ontario, now for 11-16 years with N (NO3 NH4) at 0.6, 3.2, and 6.4 g N m-2 y-1 (~5, 10 and 20 times ambient N deposition during summer months) with and without phosphorus (P) and potassium (K). Treatments were applied to triplicate plots (3 x 3 m) from May - August 2000-2015 and control plots received distilled water. We measured CH4 fluxes with static chambers weekly from May to September 2015 and peat samples were incubated in laboratory to measure CH4 production and consumption potentials. Methane fluxes at the site were generally low, but after 16 years, mean CH4 emissions have increased and more than doubled in high nitrogen addition treatments if P and K input was also increased (3.2 and 6.4 g N m-2yr-1 with PK), owing to drastic changes in vegetation and soil moisture. Vegetation changes include a loss of Sphagnum moss and introduction of new species, typical to minerogenic mires, which together with increased decomposition have led to decreased surface elevation and to higher water table level relative to the surface. The trajectories indicate that the N only treatments may result in similar responses, but only over longer time scales. Elevated atmospheric deposition of nutrients to peatlands may increase loss of C not only due to changes in CO2 exchange but also due to enhanced CH4 emissions in peatlands through a complex suite of feedbacks and interactions among vegetation, microclimate, and microbial processes. It is uncertain, however, how the vegetation change continues due to collapsing surface and higher water table levels, and how that will affect future CH4 emissions and C balance.

High-resolution age modelling of peat bog profiles using pre and post-bomb 14C, 210Pb and cryptotephra data from six Albertan peat bogs

NASA Astrophysics Data System (ADS)

Davies, L. J.; Froese, D. G.; Appleby, P.; van Bellen, S.; Magnan, G.; Mullan-Boudreau, G.; Noernberg, T.; Shotyk, W.; Zaccone, C.

2016-12-01

Age modelling of recent peat profiles is frequently undertaken for high-resolution modern studies, but the most common techniques applied (e.g. 14C, 210Pb, cryptotephra) are rarely combined and used for testing and inter-comparison. Here, we integrate three age-dating approaches to produce a single age model to comprehensively investigate variations in the chronometers and individual site histories since 1900. OxCal's P_Sequence function is used to model dates produced using 14C (pre- and post-bomb), 210Pb (corroborated with 137Cs and 241Am) from six peat bogs in central and northern Alberta. Physical and chemical characteristics of the cores (e.g. macrofossils, humification, ash content, dry density) provide important constraints for the model by highlighting periods with significant changes in accumulation rate (e.g. fire events, permafrost development, prolonged surficial drying). Sub-cm resolution output shows there are consistent differences in how the 14C and 210Pb signals are preserved in peat profiles, with 14C commonly showing a slight bias toward older ages at the same depth relative to 210Pb data. These methods can successfully be combined in a Bayesian model and used to produce a single age model that more accurately accounts for the uncertainties inherent in each method. Understanding these differences and combining the results of these methods results in a stronger chronology at each site investigated here despite observed differences in ecological setting, accumulation rates, fire events/frequency and permafrost development.

Terrestrial Responses to Variability in the Southern Westerlies Inferred from Deep Holocene Peat Archives

NASA Astrophysics Data System (ADS)

Hughes, P. D. M.; Mauquoy, D.; van Bellen, S.; Roland, T. P.; Loader, N.; Street-Perrott, F. A.; Daley, T.

2017-12-01

The deep ombrotrophic peat bogs of Chile are located throughout the latitudes dominated by the southern westerly wind belt. The domed surfaces of these peatlands make them sensitive to variability in summer atmospheric moisture balance and the near-continuous accumulation of deep peat strata throughout the Holocene to the present day means that these sites provide undisturbed archives of palaeoclimatic change. We have reconstructed late-Holocene bog water table depths - which can be related to changes in the regional balance of precipitation to evaporation (P-E) - from a suite of peat bogs located in three areas of Tierra del Feugo, Chile, under the main path of the SWWB. Water-table depths were reconstructed from sub-fossil testate amoebae assemblages using a conventional transfer function to infer past water-table depths, based on taxonomic classification of tests but also an innovative trait-based transfer function to infer the same parameter. Water table reconstructions derived from the two methods were consistent within sites. They show that mire water tables have been relatively stable in the last 2000 years across Tierra del Feugo. Higher water table levels, most probably indicating increased effective precipitation, were found between c. 1400 and 900 cal. BP., whereas a consistent drying trend was reconstructed across the region in the most recent peat strata. This shift may represent a pronounced regional decrease in precipitation and/or a change to warmer conditions linked to strengthening of the SWWB. However, other factors such as recent thinning of the ozone layer over Tierra del Fuego could have contributed to recent shifts in some testate amoebae species.

Recent atmospheric lead deposition recorded in an ombrotrophic peat bog of Great Hinggan Mountains, Northeast China, from 210Pb and 137Cs dating.

PubMed

Bao, K; Xia, W; Lu, X; Wang, G

2010-09-01

Radioactive markers are useful in dating lead deposition patterns from industrialization in peat archive. Peat cores were collected in an ombrotrophic peat bog in the Great Hinggan Mountains in Northeast China in September 2008 and dated using (210)Pb and (137)Cs radiometric techniques. The mosses in both cores were examined systematically for dry bulk density, water and ash content. Lead also was measured using atomic emission spectroscopy with inductively coupled plasma (ICP-AES). Both patterned peat profiles were preserved well without evident anthropogenic disturbance. Unsupported (210)Pb and (137)Cs decreased with the depth in both of the two sample cores. The (210)Pb chronologies were established using the constant rate of supply model (CRS) and are in good agreement with the (137)Cs time marker. Recent atmospheric (210)Pb flux in Great Hinggan Mountains peat bog was estimated to be 337 Bq m(-2)y(-1), which is consistent with published data for the region. Lead deposition rate in this region was also derived from these two peat cores and ranged from 24.6 to 55.8 mg m(-2)y(-1) with a range of Pb concentration of 14-262 microg g(-1). The Pb deposition patterns were consistent with increasing industrialization over the last 135-170 y, with a peak of production and coal burning in the last 50 y in Northeast China. This work presents a first estimation of atmospheric Pb deposition rate in peatlands in China and suggests an increasing trend of environmental pollution due to anthropogenic contaminants in the atmosphere. More attention should be paid to current local pollution problems, and society should take actions to seek a balance between economic development and environmental protection. Copyright 2010 Elsevier Ltd. All rights reserved.

Intercomparison of radiocarbon bomb pulse and 210Pb age models. A study in a peat bog core from North Poland

NASA Astrophysics Data System (ADS)

Piotrowska, Natalia; De Vleeschouwer, François; Sikorski, Jarosław; Pawlyta, Jacek; Fagel, Nathalie; Le Roux, Gaël; Pazdur, Anna

2010-04-01

Radiocarbon and 210Pb were measured on the uppermost 40 cm of a Wardenaar peat core retrieved from a Baltic raised bog at Słowińskie Błota (Pomerania, North Poland). This site is the subject of ongoing multiproxy studies covering the last 1300 years. Radiocarbon age model was constructed on the basis of 14 AMS dates obtained on selected Sphagnum spp. fragments, with use of P_Sequence tool. We present here a comparison of this model with the age model obtained using CRS model classically applied to 210Pb measurements.

Effect of water-table fluctuations on the degradation of Sphagnum phenols in surficial peats

NASA Astrophysics Data System (ADS)

Abbott, Geoffrey D.; Swain, Eleanor Y.; Muhammad, Aminu B.; Allton, Kathryn; Belyea, Lisa R.; Laing, Christopher G.; Cowie, Greg L.

2013-04-01

A much improved understanding of how water-table fluctuations near the surface affect decomposition and preservation of peat-forming plant litter and surficial peats is needed in order to predict possible feedbacks between the peatland carbon cycle and the global climate system. In this study peatland plants (bryophytes and vascular plants), their litter and peat cores were collected from the Ryggmossen peatland in the boreonemoral zone of central Sweden. The extracted insoluble residues from whole plant tissues were depolymerized using thermally assisted hydrolysis and methylation (THM) in the presence of both unlabelled and 13C-labelled tetramethylammonium hydroxide (TMAH) which yielded both vascular plant- and Sphagnum-derived phenols. Methylated 4-isopropenylphenol (IUPAC: 1-methoxy-4-(prop-1-en-2-yl)benzene), methylated cis- and trans-3-(4'-hydroxyphen-1-yl)but-2-enoic acid (IUPAC: (E/Z)-methyl 3-(4-methoxyphenyl)but-2-enoate), and methylated 3-(4'-hydroxyphen-1-yl)but-3-enoic acid (IUPAC: methyl 3-(4-methoxyphenyl)but-3-enoate) (van der Heijden et al., 1997) are confirmed as TMAH thermochemolysis products of "bound" sphagnum acid and also as being specific to Sphagnum mosses. These putative biomarkers were also significant components in the unlabelled TMAH thermochemolysis products from the depolymerization of ultrasonically extracted samples from eight peat cores, one from a hummock and one from a hollow at each of the four stages along the bog plateau-to-swamp forest gradient. We have proposed and measured two parameters namely (i) σ which is defined as the total amount of these four molecules normalised to 100 mg of OC; and (ii) an index (SR%) which is the ratio of σ to the Λ parameter giving a measure of the relative amounts of "bound" sphagnum acid to the "bound" vascular plant phenols in peat moss and the surficial peat layers. Changes in σ and SR% down the bog plateau (BP), bog margin (BM) and fen lagg (FL) cores in the Ryggmossen mire indicates that the sphagnum acid bound into the peat is being degraded in the unsaturated and seasonally-saturated layers. There is then a stabilisation of Sphagnum-derived phenols in the deepest horizons of the seasonally-saturated layer and into the permanently-saturated layer. These results suggest that "bound" sphagnum acid will be stabilised in peatlands shifting to a wetter and more variable precipitation regime whereas it will be gradually stripped away (e.g. by hydrolysis/enzymatic activity) in surficial peats shifting to a drier climate, such that any subsequent rewetting of the peat could lead to anaerobic hydrolysis and fermentation of the newly exposed carbohydrates. This highlights the sensitivity of Sphagnum surficial peats to climate-induced changes in water levels albeit there may be differences in the extent of degradation along the bog-fen gradient.

Only low methane production and emission in degraded peat extraction sites after rewetting

NASA Astrophysics Data System (ADS)

Agethen, Svenja; Waldemer, Carolin; Knorr, Klaus-Holger

2015-04-01

In Central Europe rewetting of bogs after peat extraction is a wide spread technique to halt secondary aerobic decomposition and to reestablish plant species such as Sphagnum spp. and Eriophorum spp. that initialize accumulation of organic carbon in peat. Before extraction, such sites are often used for agriculture causing the aerobic degradation of peat and mobilization of phosphorus, ammonia, and dissolved organic matter (DOM). In nutrient poor ecosystems such as bogs, additional supply of P and N does not only trigger the establishment of uncharacteristic vegetation but also the formation of more labile plant litter and DOM that is readily degradable. Therefore, after rewetting and the development of anoxic conditions especially in initial stages high methane (CH4) emissions are reported for these systems compared to pristine bogs. Regarding the potential of methane production and emissions we investigated three common practices to prepare extraction fields for restoration (years since rewetting): i) Filling of drainage ditches, passive rewetting (1 site, Altendorfer Moor, Stade, NW-Germany, ca. 20 yr.), ii) Removal of upper 30 cm peat layer, removed peat used for construction of polder dikes (2 sites, Königsmoor, Leer, NW-Germany, 2 and 3 yr.), iii) Removal upper peat layer down to 50 cm grown peat, not extracted peat used as polder walls (2 sites, Benthullener Moor, Wardenburg, NW-Germany, 3 and 7 yr.). In each site two vegetated replicate mesocosms (diam. 30 cm, depth 40 cm) were sampled and placed in a greenhouse from May-October 2014 to maintain the water table at surface level. Pore water concentrations of ions, fermentation products and DOM, DOM electron acceptor capacity (EAC), soil gas concentrations of CO2, CH4 and H2, gas fluxes as well as element composition and organic matter quality of DOM and SOM were analyzed. We found out that practice i) with least efforts of nutrient removal in the peat produced the highest CH4 emissions (3.5 mmol m-2 d-1) although still within the range of northern pristine bogs. Also practice ii) showed still inputs of external nutrients and labile DOM, but CH4 production was not yet developed (0.23 and 0.07 mmol m-2 d-1). Practice iii) was most effective in nutrient removal, but only in the 7 yr. site little methane (in the 3 yr. site 0.025 vs. 0.41 mmol m-2 d-1in the 7 yr. site) was emitted. The emissions were well in accord with soil gas concentrations, maximum values for CH4 in practice i) were 115 μmol L-1, 2-5 μmol L-1 in practice ii) and 0.5 vs. 16 μmol L-1 in practice iii). Only small concentrations of inorganic electron acceptors such as sulfate imply the importance of organic matter as electron acceptor. The results show that restored bogs on former strongly degraded extraction fields do not necessarily act as exceptionally high CH4 sources. Contrary to other findings in early stages of rewetting CH4 emissions can also be very low until other electron acceptors are exhausted and methanogens become effective competitors for substrates which happens in the order of years.

Spatial variability in plant species composition and peatland carbon exchange

NASA Astrophysics Data System (ADS)

Goud, E.; Moore, T. R.; Roulet, N. T.

2015-12-01

Plant species shifts in response to global change will have significant impacts on ecosystem carbon (C) exchange and storage arising from changes in hydrology. Spatial variation in peatland C fluxes have largely been attributed to the spatial distribution of microhabitats that arise from variation in surface topography and water table depth, but little is known about how plant species composition impacts peatland C cycling or how these impacts will be influenced by changing environmental conditions. We quantified the effect of species composition and environmental variables on carbon dioxide (CO2) and methane (CH4) fluxes over 2 years in a temperate peatland for four plant communities situated along a water table gradient from ombrotrophic bog to beaver pond. We hypothesized that (i) spatial heterogeneity in species composition would drive predictable spatial heterogeneity in C fluxes due to variation in plant traits and ecological tolerances, and (ii) increases in peat temperature would increase C fluxes. Species had different effects on C fluxes primarily due to differences in leaf traits. Differences in ecological tolerances among communities resulted in different rates of CO2 exchange in response to changes in water table depth. There was an overall reduction in ecosystem respiration (ER), gross primary productivity (GPP) and CH4 flux in response to colder peat temperatures in the second year, and the additive effects of a deeper water table in the bog margin and pond sites further reduced flux rates in these areas. These results demonstrate that different plant species can increase or decrease the flux of C into and out of peatlands based on differences in leaf traits and ecological tolerances, and that CO2 and CH4 fluxes are sensitive to changes in soil temperature, especially when coupled with changes in moisture availability.

Vegetation change and terrestrial carbon storage in eastern Asia during the Last Glacial Maximum as indicated by a new pollen record from central Taiwan

NASA Astrophysics Data System (ADS)

Liew, P. M.; Kuo, C. M.; Huang, S. Y.; Tseng, M. H.

1998-05-01

Last Glacial Maximum (LGM) carbon storage in eastern Asia is a key issue for understanding the sinks and sources of paleocarbon. Palynological data with good time constraint for the LGM in a peat bog from a site at 650 m above mean sea level in central Taiwan, together with data from low-lying deltaic and basin deposits of Taiwan and South China, increase our understanding about vegetational evolution and possible terrestrial carbon storage in this area and probably eastern Asia. Contrasting to today's Machilus-Castanopsis forest zone around the peat bog, the vegetation before the LGM was dominated by Alnus, a relatively xerophytic element in Taiwan. An increase in herbs and decrease in spores during the LGM is recognized when compared with Holocene and modern assemblages. A less humid interval dominated by herbs (>50%) occurred between 21 and 15.8 ka. Basin deposits in northern Taiwan and deltaic deposits in central Taiwan show that during the LGM Artemisia, Umbelliferae and Gramineae were the main components contrasting with the Pinus or Cyclobalanopsis-dominant assemblages in the rest of the last glacial. Thus, less humid conditions lasted about 5000 to 6000 years in the LGM even on this very humid island. This may also be true in eastern Asia where a large area of the widely exposed continental shelf may have been occupied by grasslands and the uplands of South China were occupied by less dense coniferous or temperate forests during the LGM in contrast to the modern subtropical forest. This scenario improves our understanding of the terrestrial paleocarbon storage.

Mid- and late Holocene human impact recorded by the Coltrondo peat bog (NE Italian Alps)

NASA Astrophysics Data System (ADS)

Segnana, Michela; Poto, Luisa; Gabrieli, Jacopo; Martino, Matteo; Oeggl, Klaus; Barbante, Carlo

2016-04-01

Peat bogs are ideal archives for the study of environmental changes, whether these are natural or human induced. Indeed, receiving water and nutrients exclusively from dry and wet atmospheric depositions, they are among the most suitable matrices for palaeoenvironmental reconstruction. The present study is focused on the Eastern sector of the Italian Alps, where we sampled the Coltrondo peat bog, in the Comelico area (ca. 1800 m a.s.l.) The knowledge of the human history in this area is rather scarce: the only pieces of archaeological evidence found in this area dates back to the Mesolithic and the absence of later archaeological finds makes it difficult to reconstruct the human settlement in the valley. With the main aim to obtain information about the human settlement in that area we selected a multi-proxy approach, combining the study of biotic and abiotic sedimentary components archived in the 7900 years-peat bog record. Pollen analysis is performed along the core registering human impacts on the area from ca. 2500 cal BP, when land-use changes are well evidenced by the presence of human-related pollen and non-pollen palynomorphs (NPPs), as well as by the increase in micro-charcoal particles. Periods of increased human impact are recorded at the end of the Middle Ages and later, at the end of the 19th century. The analysis of trace elements, such as lead, is performed by means of ICP-MS technique and its enrichment factor (EF) is calculated. A first slight increase of Pb EF during Roman Times is possibly related to mining activities carried out by the Romans. Mining activities carried out in the area are registered during the Middle Ages, while the advent of the industrialization in the 20th century is marked by the highest EF values registered on the top of the core. To help and support the interpretation of geochemical data, lead isotopes ratios are also measured using ICP-MS to discriminate between natural and anthropogenic sources of lead. The 206Pb/207Pb ratio clearly records a pre-anthropogenic period from 7800 to 2500 cal BP, followed by a period in which humans impacted on the environment. During the Middle Ages the 206Pb/207Pb ratio values are attributable to mining activities, while during Modern Times they are mostly linked to industrial activities and to the introduction of leaded gasoline in Italy. The phasing out of leaded gasoline in the 1980s is also registered by the peat bog. Finally, the still on-going analysis of organic biomarkers in the peat seems to corroborate the results achieved, adding information about local disturbances on the bog. The multi-proxy approach selected for this study allows us to discriminate between different aspects of the past human presence, such as forest clearance, fires, agriculture, pasture, mining and industrial activities, giving new insights into the history of the Comelico area, still scarcely investigated.

Retention of atmospheric Cu, Ni, Cd and Zn in an ombrotrophic peat profile near the Outokumpu Cu-Ni mine, SE-Finland

NASA Astrophysics Data System (ADS)

Rausch, N.; Nieminen, T. M.; Ukonmaanaho, L.; Cheburkin, A.; Krachler, M.; Shotyk, W.

2003-05-01

Peat cores taken from ombrotrophic bogs are widely used to reconstruct historical records of atmospheric lead and mercury déposition[1, 2]. In this study, the retention of copper, nickel, cadmium and zinc in peat bogs are studied by comparing high resolution, age dated concentration profiles with emissions from the main local source, the Outokumpu copper-nickel mine. An ombrotrophic peat core was taken from the vicinity of Outokumpu, E Finland. Copper and zinc concentrations of dry peat were measured by XRF, cadmium and nickel by GF-AAS, and sample ages by 210Pb. Only copper and nickel show enhanced concentrations in layers covering the mining period, indicating a retention of these elements. However, the more detailed comparison of ore production rates and concentrations in age-dated samples show clearly that only copper is likely to be permanently fixed, while nickel doesn't reflect the mining activity. Even though copper is retained in the upper part of the profile, a possible redeposition of this element by secondary processes (e.g., water table fluctuations) can not be excluded. This question will be resolved by further investigations, e.g. by pore water profiles.

Contemporary Mobilization of Legacy Pb Stores by DOM in a Boreal Peatland.

PubMed

Jeremiason, Jeff D; Baumann, Erin I; Sebestyen, Stephen D; Agather, Alison M; Seelen, Emily A; Carlson-Stehlin, Benjamin J; Funke, Meghan M; Cotner, James B

2018-03-20

We examined how different landscape areas in a catchment containing a northern ombrotrophic peatland and upland mineral soils responded to dramatic decreases in atmospheric deposition of lead (Pb). Pb concentrations in the outflow stream from the peatland measured from 2009-2015 indicated continued mobilization and export of Pb derived from historic inputs to the bog. In contrast, Pb concentrations in surface peat and runoff from upland mineral soils have declined in response to reductions in atmospheric deposition. Relative to the early 1980s, Pb concentrations in the streamflow decreased only ∼50%, while Pb in surface peat and upland subsurface runoff decreased by more than 90%. Water level fluctuations in the slow-accumulating peat have allowed dissolved organic matter (DOM) to continue mobilizing Pb deposited in the peatland decades earlier. Strong correlations between dissolved organic carbon (DOC) and Pb concentrations in outflow from the peatland and in bog porewaters demonstrate Pb mobility related to DOM production. Peat stores of Pb in 2016 were less than or equal to those reported in the early 1980s despite the dry mass inventory increasing by 60-80%. Much of the loss in Pb stored in peat can be accounted for by stream runoff from the peatland.

Ecology of southeastern shrub bogs (pocosins) and Carolina bays: a community profile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharitz, R.R.; Gibbons, J.W.

1982-11-01

Shrub bogs of the Southeast occur in areas of poorly developed internal drainage that typically but not always have highly developed organic or peat soils. Pocosins and Carolina bays are types or subclasses of shrub bogs on the coastal plains of the Carolinas and Georgia. They share roughly the same distribution patterns, soil types, floral and faunal species composition and other community attributes, but differ in geological formation. Carolina bays may contain pocosin as well as other communities, but are defined more by their unique elliptical shape and geomorphometry. The pocosin community is largely defined by its vegetation, a combinationmore » of a dense shrub understory and a sparser canopy. The community is part of a complex successional sequence of communities (sedge bogs, savannas, cedar bogs, and bay forests) that may be controlled by such factors as fire, hydroperiod, soil type, and peat depth. Pocosins and Carolina bays harbor a number of animal groups and may be locally important in their ecology. Although few species are endemic to these habitats, they may provide important refuges for a number of species. These communities are simultaneously among the least understood and most rapidly disappearing habitats of the Southeast. Forestry and agricultural clearage are current impacts.« less

Dendrochronologically dated pine stumps document phase-wise bog expansion at a northwest German site between ca. 6700 and ca. 3400 BC

NASA Astrophysics Data System (ADS)

Maike Achterberg, Inke Elisabeth; Eckstein, Jan; Birkholz, Bernhard; Bauerochse, Andreas; Leuschner, Hanns Hubert

2018-01-01

The investigated northwest German mire site at Totes Moor is densely covered with subfossil pine stumps (Pinus sylvestris L.) from the fen-bog transition. This facilitates the spatio-temporal reconstruction of mire development, which is based on 212 in situ tree stumps in the case study presented here. Six dendrochronologically dated site chronologies together cover 2345 years between 6703 and 3403 BC. The gaps in between are 6 to 550 years long. Additionally, a floating chronology of 309 years, containing 30 trees, was radiocarbon-dated to the beginning of the 7th millennium cal BC. Peat-stratigraphical survey was carried out additionally, and elevations a.s.l. were determined at several locations. Tree dying-off phases, which indicate water level rise at the site, mostly in context of the local fen-bog transition, are evident for ca. 6600-6450, ca. 6350-5750, ca. 5300-4900, ca. 4700-4550, ca. 3900-3850, ca. 3700-3600, ca. 3500-3450 and ca. 3400 BC. The spatial distribution of the dated in situ trees illustrates the phase-wise expansion of raised bog over fen peat at the site. The documented bog expansion pulses likely correspond to climatic wet sifts.

Functional traits of testate amoebae and multi-proxy data unveil exceptional Baltic bog ecohydrology, autogenic succession and climate change during the last 2000 years in CE Europe

NASA Astrophysics Data System (ADS)

Lamentowicz, Mariusz; Gałka, Mariusz; Tobolski, Kazimierz; Lamentowicz, Łukasz; Ersek, Vasile; Jassey, Vincent E. J.; van der Knaap, Willem O.

2017-04-01

We studied two peat cores from the Baltic raised bog (Mechacz Wielki in NE Poland). We aimed to separate signal of extrinsic and intrinsic forcing of the raised bog development using multi-proxy high-resolution approach. Using testate amoebae transfer function, we found that the bog revealed exceptionally stable hydrological conditions during the last 2k with a relatively high water table and lack of local fire events that allowed for rapid peat accumulation (2.75 mm/year) in the bog. Furthermore, the strong correlation between pH and community-weighted mean of testate amoeba traits suggests that other variables than water-table depth play a role in driving microbial properties under stable hydrological conditions. There is a difference in hydrological dynamics in bogs between NW and NE Poland until ca CE 1500, after which the water table reconstructions possess more similarities. Our data suggest a common regional climatic forcing in Mechacz Wielki, Gązwa and Kontolanrahka. Though it may still be too early to attempt a regional summary of wetness change in the southern Baltic region, this study is a next step to better understand the long-term peatland palaeohydrology in NE Europe. We suggest that extrinsic factors (climate) played an important role as a driver in mire development during the bog stage (AD 500-2012). Our results also show how various functional traits relate to different environmental variables in a range of trophic and hydrological scenarios on long time scales.

Peat bog wildfire smoke exposure in rural North Carolina is associated with Cardiopulmonary emergency department visits assessed through syndromic surveillance

EPA Science Inventory

Background: In June 2008 burning deposits of peat produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina (NC). While the association of mortality and morbidity with exposure to urban air ...

Peat Bog Wildfire Smoke Exposure in Rural North Carolina Is Associated with Cardio-Pulmonary Emergency Department Visits

EPA Science Inventory

In June 2008 burning deposits of peat produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina (NC). While the association of mortality and morbidity with exposure to urban air pollution i...

Vertical Stratification of Peat Pore Water Dissolved Organic Matter Composition in a Peat Bog in Northern Minnesota

NASA Astrophysics Data System (ADS)

Tfaily, Malak M.; Wilson, Rachel M.; Cooper, William T.; Kostka, Joel E.; Hanson, Paul; Chanton, Jeffrey P.

2018-02-01

We characterized dissolved organic matter (DOM) composition throughout the peat column at the Marcell S1 forested bog in northern Minnesota and tested the hypothesis that redox oscillations associated with cycles of wetting and drying at the surface of the fluctuating water table correlate with increased carbon, sulfur, and nitrogen turn over. We found significant vertical stratification of DOM molecular composition and excitation-emission matrix parallel factor analysis components within the peat column. In particular, the intermediate depth zone ( 50 cm) was identified as a zone where maximum decomposition and turnover is taking place. Surface DOM was dominated by inputs from surface vegetation. The intermediate depth zone was an area of high organic matter reactivity and increased microbial activity with diagenetic formation of many unique compounds, among them polycyclic aromatic compounds that contain both nitrogen and sulfur heteroatoms. These compounds have been previously observed in coal-derived compounds and were assumed to be responsible for coal's biological activity. Biological processes triggered by redox oscillations taking place at the intermediate depth zone of the peat profile at the S1 bog are assumed to be responsible for the formation of these heteroatomic PACs in this system. Alternatively, these compounds could stem from black carbon and nitrogen derived from fires that have occurred at the site in the past. Surface and deep DOM exhibited more similar characteristics, compared to the intermediate depth zone, with the deep layer exhibiting greater input of microbially degraded organic matter than the surface suggesting that the entire peat profile consists of similar parent material at different degrees of decomposition and that lateral and vertical advection of pore water from the surface to the deeper horizons is responsible for such similarities. Our findings suggest that molecular composition of DOM in peatland pore water is dynamic and is a function of ecosystem activity, water table, redox oscillation, and pore water advection.

Abundant Trimethylornithine Lipids and Specific Gene Sequences Are Indicative of Planctomycete Importance at the Oxic/Anoxic Interface in Sphagnum-Dominated Northern Wetlands.

PubMed

Moore, Eli K; Villanueva, Laura; Hopmans, Ellen C; Rijpstra, W Irene C; Mets, Anchelique; Dedysh, Svetlana N; Sinninghe Damsté, Jaap S

2015-09-01

Northern wetlands make up a substantial terrestrial carbon sink and are often dominated by decay-resistant Sphagnum mosses. Recent studies have shown that planctomycetes appear to be involved in degradation of Sphagnum-derived debris. Novel trimethylornithine (TMO) lipids have recently been characterized as abundant lipids in various Sphagnum wetland planctomycete isolates, but their occurrence in the environment has not yet been confirmed. We applied a combined intact polar lipid (IPL) and molecular analysis of peat cores collected from two northern wetlands (Saxnäs Mosse [Sweden] and Obukhovskoye [Russia]) in order to investigate the preferred niche and abundance of TMO-producing planctomycetes. TMOs were present throughout the profiles of Sphagnum bogs, but their concentration peaked at the oxic/anoxic interface, which coincided with a maximum abundance of planctomycete-specific 16S rRNA gene sequences. The sequences detected at the oxic/anoxic interface were affiliated with the Isosphaera group, while sequences present in the anoxic peat layers were related to an uncultured planctomycete group. Pyrosequencing-based analysis identified Planctomycetes as the major bacterial group at the oxic/anoxic interface at the Obukhovskoye peat (54% of total 16S rRNA gene sequence reads), followed by Acidobacteria (19% reads), while in the Saxnäs Mosse peat, Acidobacteria were dominant (46%), and Planctomycetes contributed to 6% of the total reads. The detection of abundant TMO lipids in planctomycetes isolated from peat bogs and the lack of TMO production by cultures of acidobacteria suggest that planctomycetes are the producers of TMOs in peat bogs. The higher accumulation of TMOs at the oxic/anoxic interface and the change in the planctomycete community with depth suggest that these IPLs could be synthesized as a response to changing redox conditions at the oxic/anoxic interface. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Abundant Trimethylornithine Lipids and Specific Gene Sequences Are Indicative of Planctomycete Importance at the Oxic/Anoxic Interface in Sphagnum-Dominated Northern Wetlands

PubMed Central

Villanueva, Laura; Hopmans, Ellen C.; Rijpstra, W. Irene C.; Mets, Anchelique; Dedysh, Svetlana N.

2015-01-01

Northern wetlands make up a substantial terrestrial carbon sink and are often dominated by decay-resistant Sphagnum mosses. Recent studies have shown that planctomycetes appear to be involved in degradation of Sphagnum-derived debris. Novel trimethylornithine (TMO) lipids have recently been characterized as abundant lipids in various Sphagnum wetland planctomycete isolates, but their occurrence in the environment has not yet been confirmed. We applied a combined intact polar lipid (IPL) and molecular analysis of peat cores collected from two northern wetlands (Saxnäs Mosse [Sweden] and Obukhovskoye [Russia]) in order to investigate the preferred niche and abundance of TMO-producing planctomycetes. TMOs were present throughout the profiles of Sphagnum bogs, but their concentration peaked at the oxic/anoxic interface, which coincided with a maximum abundance of planctomycete-specific 16S rRNA gene sequences. The sequences detected at the oxic/anoxic interface were affiliated with the Isosphaera group, while sequences present in the anoxic peat layers were related to an uncultured planctomycete group. Pyrosequencing-based analysis identified Planctomycetes as the major bacterial group at the oxic/anoxic interface at the Obukhovskoye peat (54% of total 16S rRNA gene sequence reads), followed by Acidobacteria (19% reads), while in the Saxnäs Mosse peat, Acidobacteria were dominant (46%), and Planctomycetes contributed to 6% of the total reads. The detection of abundant TMO lipids in planctomycetes isolated from peat bogs and the lack of TMO production by cultures of acidobacteria suggest that planctomycetes are the producers of TMOs in peat bogs. The higher accumulation of TMOs at the oxic/anoxic interface and the change in the planctomycete community with depth suggest that these IPLs could be synthesized as a response to changing redox conditions at the oxic/anoxic interface. PMID:26150465

Impact of the Little Ice Age cooling and 20th century climate change on peatland vegetation dynamics in central and northern Alberta using a multi-proxy approach and high-resolution peat chronologies

NASA Astrophysics Data System (ADS)

Magnan, Gabriel; van Bellen, Simon; Davies, Lauren; Froese, Duane; Garneau, Michelle; Mullan-Boudreau, Gillian; Zaccone, Claudio; Shotyk, William

2018-04-01

Northern boreal peatlands are major terrestrial sinks of organic carbon and these ecosystems, which are highly sensitive to human activities and climate change, act as sensitive archives of past environmental change at various timescales. This study aims at understanding how the climate changes of the last 1000 years have affected peatland vegetation dynamics in the boreal region of Alberta in western Canada. Peat cores were collected from five bogs in the Fort McMurray region (56-57° N), at the southern limit of sporadic permafrost, and two in central Alberta (53° N and 55° N) outside the present-day limit of permafrost peatlands. The past changes in vegetation communities were reconstructed using detailed plant macrofossil analyses combined with high-resolution peat chronologies (14C, atmospheric bomb-pulse 14C, 210Pb and cryptotephras). Peat humification proxies (C/N, H/C, bulk density) and records of pH and ash content were also used to improve the interpretation of climate-related vegetation changes. Our study shows important changes in peatland vegetation and physical and chemical peat properties during the Little Ice Age (LIA) cooling period mainly from around 1700 CE and the subsequent climate warming of the 20th century. In some bogs, the plant macrofossils have recorded periods of permafrost aggradation during the LIA with drier surface conditions, increased peat humification and high abundance of ericaceous shrubs and black spruce (Picea mariana). The subsequent permafrost thaw was characterized by a short-term shift towards wetter conditions (Sphagnum sect. Cuspidata) and a decline in Picea mariana. Finally, a shift to a dominance of Sphagnum sect. Acutifolia (mainly Sphagnum fuscum) occurred in all the bogs during the second half of the 20th century, indicating the establishment of dry ombrotrophic conditions under the recent warmer and drier climate conditions.

Late-Holocene Climate Change and Human Impact; Palaeoecological Evidence From Peat Deposits in Sweden and Germany

NASA Astrophysics Data System (ADS)

van der Linden, M.; van Geel, B.

2006-12-01

With the aim of investigating the effects of climate change and human impact on vegetation and carbon accumulation, we took peat cores of ca. 1 meter depth from four raised bogs situated on a North-South transect, at intervals of c. 500 km, Umeå in Sweden to Angermünde in northern Germany. A number of analyses were conducted (plant macrofossils, pollen/non-pollen microfossils, colorimetric humification, carbon/nitrogen ratios, bulk densities, loss on ignition), and 14C wiggle-match dating was applied to obtain a fine-resolution chronology. The cores from the northern and southern site encompass ca. 1000 years of vegetation history, showing evidence for the end of the Medieval Warm Period (MWP), the Little Ice Age (LIA) and the twentieth century warming. The middle Swedish and German sites are high resolution records of the last 400 years. The end of the MWP and the cooling at the start of the LIA are reflected by a decline in thermophilous tree species. Changes in the macrofossil composition may also represent changes in climate. Shifts in Sphagnum composition, the dominant peat former, reflect changes in precipitation. Evidence for wet conditions and increased carbon accumulation is found during the Little Ice Age. Human activities affected the peat bog and the surrounding vegetation. Sweden suffered many wars during the 16^{th} and 17^{th} century, which caused a decline in population density. Diseases such as the plague and famines caused by crop failures fastened the population decrease. As a consequence, agricultural land was abandoned, resulting in reforestation by Betula. Later, in the modern part of the records, land-use change and planting of trees comprised the major regional vegetation changes. In the southern site, human activities (drainage to facilitate peat cutting) affected the raised bog itself. A part of the peat archive was lost owing to secondary decomposition which resulted in very low carbon accumulation.

Effects of long-term drainage on microbial community composition vary between peatland types

NASA Astrophysics Data System (ADS)

Urbanová, Zuzana; Barta, Jiri

2016-04-01

Peatlands represent an important reservoir of carbon, but their functioning can be threatened by water level drawdown caused by climate or land use change. Knowledge of how microbial communities respond to long-term drainage in different peatland types could help improve predictions of the effect of climate change on these ecosystems. We investigated the effect of long-term drainage on microbial community composition in bog, fen and spruce swamp forests (SSF) in the Sumava Mountains (Czech Republic), using high-throughput barcoded sequencing, in relation to peat biochemical properties. Longterm drainage had substantial effects, which depended strongly on peatland type, on peat biochemical properties and microbial community composition. The effect of drainage was most apparent on fen, followed by SSF, and lowest on bog. Long-term drainage led to lower pH, reduced peat decomposability and increased bulk density, which was reflected by reduced microbial activity. Bacterial diversity decreased and Acidobacteria became the dominant phylum on drained sites, reflecting a convergence in bacterial community composition across peatlands after long-term drainage. The archaeal communities changed very strongly and became similar across drained peatlands. Overall, the characteristic differences between distinct peatland types under natural conditions were diminished by long-term drainage. Bog represented a relatively resilient system while fen seemed to be very sensitive to environmental changes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rutherford, L.A.; Matthews, S.L.

A study was conducted to determine historical atmospheric mercury deposition patterns in the Maritime Provinces. Investigators measured mercury concentrations in peat cores from five ombrotrophic bogs in Kejimkujik, Fundy, Kouchibougouac, and Cape Breton Highlands national parks and in East Baltic Bog, Prince Edward Island. Results presented and discussed include deposition rates calculated using lead-210 date estimates, temporal trends in mercury concentrations, and spatial patterns of mercury deposition.

Holocene climate variability in the western Mediterranean through a multiproxy analysis from Padul peat bog (Sierra Nevada, Spain)

NASA Astrophysics Data System (ADS)

Ramos-Román, María J.; Jiménez-Moreno, Gonzalo; Camuera, Jon; García-Alix, Antonio; Anderson, R. Scott; Jiménez-Espejo, Francisco J.; Sachse, Dirk

2017-04-01

The Iberian Peninsula, located in the Mediterranean area, is an interesting location for paleoclimate studies due to its geographic situation between arid and humid climates. Sediments from peat bogs and lakes from Sierra Nevada, in southeastern Iberian Peninsula, have been very informative in terms of how vegetation and wetland environments were impacted by Holocene climate change. These studies are essential if we want to understand the past climate change in the area, which is the key to identify the possible environmental response of the Sierra Nevada ecosystems to future climate scenarios. Padul basin, located in the southwest of the Sierra Nevada mountain range, contains a ca. 100 m-thick peat bog sedimentary sequence that was deposited during the past 1 Ma making this area interesting for paleoenvironmental and paleoclimatic reconstructions. A new 43 m-long sedimentary record has recently been retrieved from the Padul peat bog. In this study we have developed a multiproxy analysis of the Holocene part of the Padul-15-05 core including pollen analysis, XRF-core scanner, magnetic susceptibility and organic geochemistry, supported by an age control based on AMS radiocarbon dates, providing with information about vegetation and climate variability during the past 9.9 cal ka BP. This multiproxy reconstruction of the Padul-15-05 evidences the Mediterranean as a sensitive area with respect to global-scale climate system, showing relevant climate episodes such as the ca. 8, 7.5, 6.5 and 5.5 cal ka BP events during the early and middle Holocene. The trend to aridification to the late Holocene is interrupted by more arid and humid periods as the Iberian Roman Humid Period (from ca. 3 to 1.6 cal ka BP), the Dark Ages (from ca. 1.5 to 1.1 cal ka BP), the Medieval Climate Anomaly (from ca. 1.1 to 1.3 cal ka BP) and the Little Ice Age period (from ca. 500 to 100 cal yr BP).

Peatland Microbial Communities and Decomposition Processes in the James Bay Lowlands, Canada

PubMed Central

Preston, Michael D.; Smemo, Kurt A.; McLaughlin, James W.; Basiliko, Nathan

2012-01-01

Northern peatlands are a large repository of atmospheric carbon due to an imbalance between primary production by plants and microbial decomposition. The James Bay Lowlands (JBL) of northern Ontario are a large peatland-complex but remain relatively unstudied. Climate change models predict the region will experience warmer and drier conditions, potentially altering plant community composition, and shifting the region from a long-term carbon sink to a source. We collected a peat core from two geographically separated (ca. 200 km) ombrotrophic peatlands (Victor and Kinoje Bogs) and one minerotrophic peatland (Victor Fen) located near Victor Bog within the JBL. We characterized (i) archaeal, bacterial, and fungal community structure with terminal restriction fragment length polymorphism of ribosomal DNA, (ii) estimated microbial activity using community level physiological profiling and extracellular enzymes activities, and (iii) the aeration and temperature dependence of carbon mineralization at three depths (0–10, 50–60, and 100–110 cm) from each site. Similar dominant microbial taxa were observed at all three peatlands despite differences in nutrient content and substrate quality. In contrast, we observed differences in basal respiration, enzyme activity, and the magnitude of substrate utilization, which were all generally higher at Victor Fen and similar between the two bogs. However, there was no preferential mineralization of carbon substrates between the bogs and fens. Microbial community composition did not correlate with measures of microbial activity but pH was a strong predictor of activity across all sites and depths. Increased peat temperature and aeration stimulated CO2 production but this did not correlate with a change in enzyme activities. Potential microbial activity in the JBL appears to be influenced by the quality of the peat substrate and the presence of microbial inhibitors, which suggests the existing peat substrate will have a large influence on future JBL carbon dynamics. PMID:22393328

Impact of the water salinity on the hydraulic conductivity of fen peat

NASA Astrophysics Data System (ADS)

Gosch, Lennart; Janssen, Manon; Lennartz, Bernd

2017-04-01

Coastal peatlands represent an interface between marine and terrestrial ecosystems; their hydrology is affected by salt and fresh water inflow alike. Previous studies on bog peat have shown that pore water salinity can have an impact on the saturated hydraulic conductivity (Ks) of peat because of chemical pore dilation effects. In this ongoing study, we are aiming at quantifying the impact of higher salinities (up to 3.5 %) on Ks of fen peat to get a better understanding of the water and solute exchange between coastal peatlands and the adjacent sea. Two approaches differing in measurement duration employing a constant-head upward-flow permeameter were conducted. At first, Ks was measured at an initial salinity for several hours before the salinity was abruptly increased and the measurement continued. In the second approach, Ks was measured for 15 min at the salt content observed during sampling. Then, samples were completely (de)salinized via diffusion for several days/weeks before a comparison measurement was carried out. The results for degraded fen peats show a decrease of Ks during long-term measurements which does not depend on the water salinity. A slow, diffusion-controlled change in salinity does not modify the overall outcome that the duration of measurements has a stronger impact on Ks than the salinity. Further experiments will show if fen peat soils differing in their state of degradation exhibit a different behavior. A preliminary conclusion is that salinity might have a less important effect on hydraulic properties of fen peat than it was observed for bog peat.

Important physical properties of peat materials

Treesearch

D.H. Boelter

1968-01-01

Peat materials from 12 bogs in northern Minnesota, U.S.A., showed significant differences in physical properties. It is pointed out that 1) these properties can be related to the hydrology of organic soils only if the soils represent undisturbed field conditions, and 2) volumetric expressions of water content are necessary to correctly evaluate the amount of water in a...

Peat Bog Wildfire Smoke Exposure in Rural North Carolina Is Associated with Cardiopulmonary Emergency Department Visits Assessed Through Syndromic Surveillance

EPA Science Inventory

In June 2008 burning deposits of peat produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina (NC). While the association of mortality and morbidity with exposure to urban air pollution is...

Decomposition and organic matter quality in continental peatlands: The ghost of permafrost past

USGS Publications Warehouse

Turetsky, M.R.

2004-01-01

Permafrost patterning in boreal peatlands contributes to landscape heterogeneity, as peat plateaus, palsas, and localized permafrost mounds are interspersed among unfrozen bogs and fens. The degradation of localized permafrost in peatlands alters local topography, hydrology, thermal regimes, and plant communities, and creates unique peatland features called "internal lawns." I used laboratory incubations to quantify carbon dioxide (CO 2) production in peat formed under different permafrost regimes (with permafrost, without permafrost, melted permafrost), and explored the relationships among proximate organic matter fractions, nutrient concentrations, and decomposition. Peat within each feature (internal lawn, bog, permafrost mound) is more chemically similar than peat collected within the same province (Alberta, Saskatchewan) or within depth intervals (surface, deep). Internal lawn peat produces more CO2 than the other peatland types. Across peatland features, acid-insoluble material (AIM) and AIM/nitrogen are significant predictors of decomposition. However, within each peatland feature, soluble proximate fractions are better predictors of CO2 production. Permafrost stability in peatlands influences plant and soil environments, which control litter inputs, organic matter quality, and decomposition rates. Spatial patterns of permafrost, as well as ecosystem processes within various permafrost features, should be considered when assessing the fate of soil carbon in northern ecosystems. ?? 2004 Springer Science+Business Media, Inc.

Impacts of regional climatic fluctuations on radial growth of Siberian and Scots pine at Mukhrino mire (central-western Siberia).

PubMed

Blanchet, Guillaume; Guillet, Sébastien; Calliari, Baptiste; Corona, Christophe; Edvardsson, Johannes; Stoffel, Markus; Bragazza, Luca

2017-01-01

Ring width (TRW) chronologies from Siberian (Pinus sibirica) and Scots (Pinus sylvestris) pine trees were sampled at Mukhrino - a large mire complex in central-western Siberia - to evaluate the impacts of hydroclimatic variability on tree growth over the last three centuries. For this purpose, we compared climate-growth correlation profiles from trees growing on peat soils with those growing on adjacent mineral soils. Tree growth at both peat and mineral soils was positively correlated to air temperature during the vegetation period. This finding can be explained by (i) the positive influence of temperature on plant physiological processes (i.e. growth control) during the growing season and (ii) the indirect impact of air temperatures on water table fluctuations. We observe also a strong link between TRW and the winter Palmer Drought Severity Index (PDSI), especially in Siberian pine, reflecting the isolating effect of snow and limited freezing damage in roots. Significant negative relations were, by contrast, observed between bog TRW chronologies and hydroclimatic indices during spring and summer; they are considered an expression of the negative impacts of high water levels and moist peat soils on root development. Some unusually old bog pines - exhibiting >500 growth rings - apparently colonized the site at the beginning of the Little Ice Age, and therefore seem to confirm that (i) peat conditions may have been drier in Siberia than in most other regions of western Europe during this period. At the same time, the bog trees also point to (ii) their strong dependence on surface conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Dynamic vertical profiles of peat porewater chemistry in a northern peatland

Treesearch

Natalie A. Griffiths; Stephen D. Sebestyen

2016-01-01

We measured pH, cations, nutrients, and total organic carbon (TOC) over 3 years to examine weekly to monthly variability in porewater chemistry depth profiles (0–3.0 m) in an ombrotrophic bog in Minnesota, USA. We also compared temporal variation at one location to spatial variation in depth profiles at 16 locations across the bog. Most solutes exhibited large...

Water storage characteristics of several peats in situ

Treesearch

D.H. Boelter

1964-01-01

Water storage characteristics of the various horizons in a northern Minnesota bog were found to vary considerably with peat type. Surface horizons of sphagnum moss contain 0.020 g. per cc. of dry material and 95 to nearly 100% water by volume at saturation. Its total porosity consisted primarily of large pores which released 0.80 cc. of water per cc. between saturation...

Greenhouse gas balance of blanket peat bog restoration from forestry in the Flow Country, Scotland

NASA Astrophysics Data System (ADS)

Hermans, Renée; Subke, Jens-Arne; Cowie, Neil; Arn Teh, Yit; Andersen, Roxane

2017-04-01

The Flow country in the far north of Scotland has the largest expanse of blanket peat bog in Europe. With peat depths of up to several metres, this area represents a significant carbon store. Large parts of the Flows were drained for afforestation with non-native conifers during the 1980s, which resulted in considerable damage to the peat, leading to significant carbon loss. To restore the peatland, the Royal Society for the Protection of Birds (RSPB) started in the late 1990s to fell trees and block drains. Over 2200 ha of forestry are felled. The main objective of this study is to measure the impact of forest removal on the budget of three main greenhouse gases, CO2, CH4 and N2O. Local variations in fluxes were measured using dark closed chambers. In order to capture abiotic conditions likely to determine microbial activity and therefor CO2, CH4 and N2O production, I record water table depth as well as soil moisture and soil temperature (both measured at 5 and 20 cm deep). These measurements are done in near pristine bog (control plot), in forest (control plot), in recently felled areas and in areas that were felled up to 19 years ago, creating a chronosequence to follow the effects of restoration. Results indicate only small differences in annual CO2 flux to the atmosphere between sites, with only the 19-year old restored site showing higher fluxes than forest control plots. However some seasonal differences in CO2 flux between land cover are evident. CH4 fluxes from forest are significantly lower than from bog and the site restored 17 years ago, and N2O fluxes are very low in all sites with no significant differences between sites. Sites where forests were removed recently (< 1 year previously) show a high degree of variability in CH4 fluxes, indicating potential flux spikes from disturbance. There is a positive correlation between soil temperature and CO2 and CH4 flux. Soil moisture varies a lot between bog, restored sites and forest, however there does not seem to be a direct correlation between soil moisture at the surface and CO2 and CH4 fluxes. Peatlands store big amounts of carbon, therefore there is a high level of importance to quantify the impact of various restoration techniques used.

2000 Years of Grazing History and the Making of the Cretan Mountain Landscape, Greece.

PubMed

Jouffroy-Bapicot, Isabelle; Vannière, Boris; Iglesias, Virginia; Debret, Maxime; Delarras, Jean-François

2016-01-01

Understanding the processes that led to the recent evolution of Mediterranean landscapes is a challenging question that can be addressed with paleoecological data. Located in the White Mountains of Crete, Asi Gonia peat bog constitutes an exceptional 2000-years-long sedimentary archive of environmental change. In this study, we document the making of the White Mountains landscape and assess human impact on ecosystem trajectories. The paleoenvironmental reconstruction is based on high-resolution analyses of sediment, pollen, dung fungal spores and charcoal obtained from a 6-m core collected from the bog. Multiproxy analyses and a robust chronological control have shed light on anthropogenic and natural processes that have driven ecological changes, giving rise to the present-day Mediterranean ecosystem. Our results suggest that sediment accumulation began during the transition from the Hellenistic to the Roman period, likely due to watershed management. The evolution of the peat bog as well as vegetation dynamics in the surrounding area were linked to past climate changes but were driven by human activities, among which breeding was of great importance. Charcoal analysis reveals that fire was largely used for the construction and maintenance of sylvo-agropastoral areas. Pollen data allow the identification of three main vegetation assemblages: 1) evergreen oak forest (before ca. 850 AD), 2) heather maquis (ca. 850 to 1870 AD), 3) phrygana/steppe landscape. Rapid changes between phases in vegetation development are associated with tipping-points in ecosystem dynamics resulting from anthropogenic impact. The modern ecosystem did not get established until the 20th century, and it is characterized by biodiversity loss along with a dramatic drying of the peat bog.

2000 Years of Grazing History and the Making of the Cretan Mountain Landscape, Greece

PubMed Central

Jouffroy-Bapicot, Isabelle; Vannière, Boris; Iglesias, Virginia; Debret, Maxime; Delarras, Jean-François

2016-01-01

Understanding the processes that led to the recent evolution of Mediterranean landscapes is a challenging question that can be addressed with paleoecological data. Located in the White Mountains of Crete, Asi Gonia peat bog constitutes an exceptional 2000-years-long sedimentary archive of environmental change. In this study, we document the making of the White Mountains landscape and assess human impact on ecosystem trajectories. The paleoenvironmental reconstruction is based on high-resolution analyses of sediment, pollen, dung fungal spores and charcoal obtained from a 6-m core collected from the bog. Multiproxy analyses and a robust chronological control have shed light on anthropogenic and natural processes that have driven ecological changes, giving rise to the present-day Mediterranean ecosystem. Our results suggest that sediment accumulation began during the transition from the Hellenistic to the Roman period, likely due to watershed management. The evolution of the peat bog as well as vegetation dynamics in the surrounding area were linked to past climate changes but were driven by human activities, among which breeding was of great importance. Charcoal analysis reveals that fire was largely used for the construction and maintenance of sylvo-agropastoral areas. Pollen data allow the identification of three main vegetation assemblages: 1) evergreen oak forest (before ca. 850 AD), 2) heather maquis (ca. 850 to 1870 AD), 3) phrygana/steppe landscape. Rapid changes between phases in vegetation development are associated with tipping-points in ecosystem dynamics resulting from anthropogenic impact. The modern ecosystem did not get established until the 20th century, and it is characterized by biodiversity loss along with a dramatic drying of the peat bog. PMID:27280287

Relative importance of local habitat complexity and regional factors for assemblages of oribatid mites (Acari: Oribatida) in Sphagnum peat bogs.

PubMed

Minor, M A; Ermilov, S G; Philippov, D A; Prokin, A A

2016-11-01

We investigated communities of oribatid mites in five peat bogs in the north-west of the East European plain. We aimed to determine the extent to which geographic factors (latitude, separation distance), local environment (Sphagnum moss species, ground water level, biogeochemistry) and local habitat complexity (diversity of vascular plants and bryophytes in the surrounding plant community) influence diversity and community composition of Oribatida. There was a significant north-to-south increase in Oribatida abundance. In the variance partitioning, spatial factors explained 33.1 % of variability in abundance across samples; none of the environmental factors were significant. Across all bogs, Oribatida species richness and community composition were similar in Sphagnum rubellum and Sphagnum magellanicum, but significantly different and less diverse in Sphagnum cuspidatum. Sphagnum microhabitat explained 52.2 % of variability in Oribatida species richness, whereas spatial variables explained only 8.7 %. There was no distance decay in community similarity between bogs with increased geographical distance. The environmental variables explained 34.9 % of the variance in community structure, with vascular plants diversity, bryophytes diversity, and ground water level all contributing significantly; spatial variables explained 15.1 % of the total variance. Overall, only 50 % of the Oribatida community variance was explained by the spatial structure and environmental variables. We discuss relative importance of spatial and local environmental factors, and make general inferences about the formation of fauna in Sphagnum bogs.

Biological N2 fixation mainly controlled by Sphagnum tissue N:P ratio in ombrotrophic bogs

NASA Astrophysics Data System (ADS)

Zivkovic, Tatjana; Moore, Tim R.

2017-04-01

Most of the 18 Pg nitrogen (N) accumulated in northern nutrient-poor and Sphagnum-dominated peatlands (bogs and fens) can be attributed to N2-fixation by diazotrophs either associated with the live Sphagnum or non-symbiotically in the deeper peat such as through methane consumption close to the water table. Where atmospheric N deposition is low (< 0.2 g m-2 y-1), ombrotrophic bogs rely on N2-fixation as the primary source of N that sustains primary production. Due to high energetic requirements, N2-fixation depends on the available phosphorus (P). Anthropogenic impacts in the last 200 years increased atmospheric N deposition, resulting in a switch from N to P limitation in Sphagnum, suggested by the increase in tissue N:P to >16. It is unclear how Sphagnum-hosted diazotrophic activity may be affected by N deposition and thus changes in N:P ratio. First, we investigated the effects of long-term addition of different sources of nitrogen (0, 1.6, 3.2 and 6.4 g N m-2 y-1as NH4Cl and NaNO3), and phosphorus (5 g P m-2 y-1as KH2PO4) on Sphagnum nutrient status (N, P and N:P ratio), net primary productivity (NPP) and Sphagnum-associated N2fixation at Mer Bleue, a temperate ombrotrophic bog. We show that N concentration in Sphagnum tissue increased with larger rates of N addition, with a stronger effect on Sphagnum from NH4 than NO3. The addition of P created a 3.5 fold increase in Sphagnum P content compared to controls. Sphagnum NPP decreased linearly with the rise in N:P ratio, while linear growth declined exponentially with increase in Sphagnum N content. Rates of N2-fixation determined in the laboratory significantly decreased in response to even the smallest addition of both N species. In contrast, the addition of P increased N2 fixation by up to 100 times compared to N treatments and up to 5-30 times compared to controls. The change in N2-fixation was best modeled by the N:P ratio, across all experimental treatments. Secondly, to test the role of N:P ratio on N2-fixation across a range of bogs, eight study sites along the latitudinal gradient from temperate, boreal to subarctic zone in eastern Canada were selected. From each bog, two predominant microptopographies, hummocks and hollows, were tested for both N2-fixation activity in the laboratory and Sphagnum tissue concentrations of N, P and N:P ratio. We found that 65% of the variance in the increase of N2-fixation activity was explained by the decrease in N:P ratio in hollows (n = 73) but only about 20% in hummocks (n = 78). Changes in neither N or P concentration alone explained the increase in N2-fixation better than N:P ratio. We interpret that the difference between hollows and hummocks results from the availability of moisture that further limits N2-fixation. When moisture is not a limiting factor, i.e. in hollows, N:P ratio will be the best predictor of N2-fixation in bogs. Both studies suggest that the relative P availability to Sphagnum-associated diazotrophs, measured as a tissue N:P ratio, best describes N2-fixation activity in bogs, especially ones exposed to larger N deposition.

Controls on the methane released through ebullition affected by permafrost degradation

Treesearch

S.J. Klapstein; M.R. Turetsky; A.D. McGuire; J.W. Harden; C.I. Czimczik; X. Xu; J.P. Chanton; J.M. Waddington

2014-01-01

Permafrost thaw in peat plateaus leads to the flooding of surface soils and the formation of collapse scar bogs, which have the potential to be large emitters of methane (CH4) from surface peat as well as deeper, previously frozen, permafrost carbon (C). We used a network of bubble traps, permanently installed 20 cm and 60 cm beneath the moss surface, to examine...

Molybdenum-Based Diazotrophy in a Sphagnum Peatland in Northern Minnesota

PubMed Central

Warren, Melissa J.; Lin, Xueju; Gaby, John C.; Kretz, Cecilia B.; Kolton, Max; Morton, Peter L.; Pett-Ridge, Jennifer; Weston, David J.; Schadt, Christopher W.; Kostka, Joel E.

2017-01-01

ABSTRACT Microbial N2 fixation (diazotrophy) represents an important nitrogen source to oligotrophic peatland ecosystems, which are important sinks for atmospheric CO2 and are susceptible to the changing climate. The objectives of this study were (i) to determine the active microbial group and type of nitrogenase mediating diazotrophy in an ombrotrophic Sphagnum-dominated peat bog (the S1 peat bog, Marcell Experimental Forest, Minnesota, USA); and (ii) to determine the effect of environmental parameters (light, O2, CO2, and CH4) on potential rates of diazotrophy measured by acetylene (C2H2) reduction and 15N2 incorporation. A molecular analysis of metabolically active microbial communities suggested that diazotrophy in surface peat was primarily mediated by Alphaproteobacteria (Bradyrhizobiaceae and Beijerinckiaceae). Despite higher concentrations of dissolved vanadium ([V] 11 nM) than molybdenum ([Mo] 3 nM) in surface peat, a combination of metagenomic, amplicon sequencing, and activity measurements indicated that Mo-containing nitrogenases dominate over the V-containing form. Acetylene reduction was only detected in surface peat exposed to light, with the highest rates observed in peat collected from hollows with the highest water contents. Incorporation of 15N2 was suppressed 90% by O2 and 55% by C2H2 and was unaffected by CH4 and CO2 amendments. These results suggest that peatland diazotrophy is mediated by a combination of C2H2-sensitive and C2H2-insensitive microbes that are more active at low concentrations of O2 and show similar activity at high and low concentrations of CH4. IMPORTANCE Previous studies indicate that diazotrophy provides an important nitrogen source and is linked to methanotrophy in Sphagnum-dominated peatlands. However, the environmental controls and enzymatic pathways of peatland diazotrophy, as well as the metabolically active microbial populations that catalyze this process, remain in question. Our findings indicate that oxygen levels and photosynthetic activity override low nutrient availability in limiting diazotrophy and that members of the Alphaproteobacteria (Rhizobiales) catalyze this process at the bog surface using the molybdenum-based form of the nitrogenase enzyme. PMID:28667112

Molybdenum-based diazotrophy in a Sphagnum peatland in northern Minnesota.

PubMed

Warren, Melissa J; Lin, Xueju; Gaby, John C; Kretz, Cecilia B; Kolton, Max; Morton, Peter L; Pett-Ridge, Jennifer; Weston, David J; Schadt, Christopher W; Kostka, Joel E; Glass, Jennifer B

2017-06-30

Microbial N 2 fixation (diazotrophy) represents an important nitrogen source to oligotrophic peatland ecosystems, which are important sinks for atmospheric CO 2 and susceptible to changing climate. The objectives of this study were: (i) to determine the active microbial group and type of nitrogenase mediating diazotrophy in a ombrotrophic Sphagnum -dominated peat bog (the S1 peat bog, Marcell Experimental Forest, Minnesota, USA); and (ii) to determine the effect of environmental parameters (light, O 2 , CO 2 , CH 4 ) on potential rates of diazotrophy measured by acetylene (C 2 H 2 ) reduction and 15 N 2 incorporation. Molecular analysis of metabolically active microbial communities suggested that diazotrophy in surface peat was primarily mediated by Alphaproteobacteria ( Bradyrhizobiaceae and Beijerinckiaceae ). Despite higher dissolved vanadium (V; 11 nM) than molybdenum (Mo; 3 nM) in surface peat, a combination of metagenomic, amplicon sequencing and activity measurements indicated that Mo-containing nitrogenases dominate over the V-containing form. Acetylene reduction was only detected in surface peat exposed to light, with the highest rates observed in peat collected from hollows with the highest water content. Incorporation of 15 N 2 was suppressed 90% by O 2 and 55% by C 2 H 2 , and was unaffected by CH 4 and CO 2 amendments. These results suggest that peatland diazotrophy is mediated by a combination of C 2 H 2 -sensitive and C 2 H 2 -insensitive microbes that are more active at low O 2 and show similar activity at high and low CH 4 Importance Previous studies indicate that diazotrophy provides an important nitrogen source and is linked to methanotrophy in Sphagnum -dominated peatlands. However, the environmental controls and enzymatic pathways of peatland diazotrophy, as well as the metabolically active microbial populations that catalyze this process remain in question. Our findings indicate that oxygen levels and photosynthetic activity override low nutrient availability in limiting diazotrophy, and that members of the Alphaproteobacteria ( Rhizobiales ) catalyze this process at the bog surface using the molybdenum-based form of the nitrogenase enzyme. Copyright © 2017 American Society for Microbiology.

Testing the potential of bacterial branched tetraether membrane lipids as temperature proxy in peat and immature coal deposits

NASA Astrophysics Data System (ADS)

Weijers, J. W. H.; Steinmann, P.; Hopmans, E. C.; Basiliko, N.; Finkelstein, S. A.; Johnson, K. R.; Schouten, S.; Sinninghe Damsté, J. S.

2012-04-01

Branched glycerol dialkyl glycerol tetraether (brGDGT) membrane lipids occur ubiquitously in peat and soil. In soil, the degree of methylation and cyclisation of branched tetraethers (MBT index and CBT ratio, respectively) has shown to relate to both soil pH and annual mean air temperature (MAT). Using this relation, past annual MATs can be reconstructed by analysing brGDGTs in marine sediment records near large river outflows. More recently, the potential of this MBT/CBT proxy is also being explored in lakes. Despite being more abundant in peat than soils, however, the utility of the proxy has not yet been fully explored in peat records. Present day peat records generally extent back to the early Holocene, but if the MBT/CBT proxy were shown to be applicable in peat deposits, there is also potential to apply it to immature coal deposits like lignites, which could provide valuable snapshots of continental climate back to the early Cenozoic. Here results are presented of analyses of different peats in south eastern Canada, showing that the pH of peat along a nutrient gradient is rather well reflected by the CBT. Annual MAT reconstructions based on the MBT/CBT soil calibration, however, tend to overestimate measured MAT. This is also the case for peat analysed from the surface of Etang de la Gruère peat bog in the Swiss Jura Mountains. Along the 6m depth profile of this bog (~13ka), CBT-reconstructed pH is compared with in-situ measured pore water pH showing that the brGDGT composition does not reflect present-day in-situ conditions. Instead, it reflects a stratigraphic boundary between Carex and Sphagnum dominated peat at 4 m depth that is not present in the pore water profile, testifying to a 'fossil' nature of the brGDGTs down the peat bog. Analyses of three immature coals of the Argonne Premium Coal Series reveal that branched GDGTs are present in the most immature coal, the Beulah Zap lignite (Ro = 0.25%), and only just above detection limit in the Wyodak Anderson coal (Ro = 0.32%), both of about the same age (Late Palaeocene). In the more mature Illinois #6 coal (Ro = 0.46%), brGDGTs are completely absent. In the Denver Basin, a comparison is made between outcrop and drilled core samples of Palaeocene lignites. BrGDGTs are preserved in the core samples, although in low quantities compared to peat. Outcrop samples are clearly overprinted by modern soil derived brGDGTs, despite digging a meters deep trench, which shows the need to obtain fresh non-weathered samples by coring. Reconstructed annual MAT for both the Beulah Zap and the Denver Basin lignites are several degrees higher than estimates based on leaf margin and oxygen isotope analyses from the same sites. Both reconstructions do testify, nevertheless, to the warm continental conditions during the early Cenozoic of the central U.S.A.. Although further validation is required, potentially in the form of a specific peat calibration, these results do show potential for application of the MBT/CBT temperature proxy in peat and lignite deposits.

Unveiling exceptional Baltic bog ecohydrology, autogenic succession and climate change during the last 2000 years in CE Europe using replicate cores, multi-proxy data and functional traits of testate amoebae

NASA Astrophysics Data System (ADS)

Gałka, Mariusz; Tobolski, Kazimierz; Lamentowicz, Łukasz; Ersek, Vasile; Jassey, Vincent E. J.; van der Knaap, Willem O.; Lamentowicz, Mariusz

2017-01-01

We present the results of high-resolution, multi-proxy palaeoecological investigations of two parallel peat cores from the Baltic raised bog Mechacz Wielki in NE Poland. We aim to evaluate the role of regional climate and autogenic processes of the raised bog itself in driving the vegetation and hydrology dynamics. Based on partly synchronous changes in Sphagnum communities in the two study cores we suggest that extrinsic factors (climate) played an important role as a driver in mire development during the bog stage (500-2012 CE). Using a testate amoebae transfer function, we found exceptionally stable hydrological conditions during the last 2000 years with a relatively high water table and lack of local fire events that allowed for rapid peat accumulation (2.75 mm/year) in the bog. Further, the strong correlation between pH and community-weighted mean of testate amoeba traits suggests that other variables than water-table depth play a role in driving microbial properties under stable hydrological conditions. There is a difference in hydrological dynamics in bogs between NW and NE Poland until ca 1500 CE, after which the water table reconstructions show more similarities. Our results illustrate how various functional traits relate to different environmental variables in a range of trophic and hydrological scenarios on long time scales. Moreover, our data suggest a common regional climatic forcing in Mechacz Wielki, Gązwa and Kontolanrahka. Though it may still be too early to attempt a regional summary of wetness change in the southern Baltic region, this study is a next step to better understand the long-term peatland palaeohydrology in NE Europe.

Alfred P. Dachnowski and the scientific study of peats

USGS Publications Warehouse

Landa, E.R.; Cohen, K.M.

2011-01-01

Botanist Alfred Paul Dachnowski (1875–1949) was a major contributor to efforts at mapping organic soils in the United States during the early 20th century. He began his career at The Ohio State University, and spent most of his professional life at the U.S. Department of Agriculture in Washington, DC. His work spanned a diversity of topics, including bog ecology and the ecosystem services provided by wetlands, the mapping and chemical characterization of peat, and the commercial applications of peat. We present a biography and overview of his work. Dachnowski is best known today for the peat sampler that bears his name. The details of its operation are described here, and its place in modern peat studies is discussed.

Spatial-temporal controls on peatland carbon dynamics in the Hudson Bay Lowland, Canada: Reducing landscape-scale uncertainty in a changing climate

NASA Astrophysics Data System (ADS)

Packalen, M. S.; Finkelstein, S. A.; McLaughlin, J.

2015-12-01

Global peatlands currently store more than 650 Pg of carbon (C) that has accumulated over millennia, and contributed to a net climatic cooling. However, controls on spatial-temporal C dynamics may differ regionally. With at least 30 Pg C sequestered in the Hudson Bay Lowlands Canada (HBL), the vulnerability of this globally significant peat C reservoir remains uncertain under conditions of a changing climate and enhanced anthropogenic pressure. Here, we synthesize our current understanding of controls on C dynamics in the HBL using detailed peat records. Our data reveal that widespread bog-fen patterning across the HBL is related to the distribution of peat C in space and time, indicating that topographic and ecohydroclimatic controls are potentially important determinants of C mass accretion. We find that while peat age is closely related to timing of land emergence and peat depth in the HBL, considerable variation in the total C mass among sites of similar peat age suggests that additional factors may further explain trends in peat C dynamics. Among these factors, we find that temperature, precipitation, and potential evapotranspiration in the HBL account for up to half of the variation in the distribution of the peat C mass, whereby regions with warmer and wetter conditions support larger peat C masses. Moreover, we find that the rate of C accumulation is greatest for young fen peatlands developing during warmer mid-Holocene climates; but that long-term C stores are greatest in association with bog peatlands. Although nearly two-thirds of HBL peat C is of late Holocene age, most of the reconstructed potential C losses also occurred during the late Holocene, as previously accrued peat decayed. Our findings support the hypothesis that both climate and ecohydrological factors are important drivers of peat C dynamics in the HBL, alongside geophysical controls on the timing of peat initiation. As the HBL peat complex continues to rapidly expand, it may remain a globally significant C reservoir. However, conservative climate scenarios predict warmer and wetter conditions in the next century, beyond the range of past climate variability. Ongoing elucidation of controls on peat C dynamics may further inform our understanding of the response of the HBL peat C reservoir to future climate and resource management scenarios.

Formation of lacustrine plains in west-central Alaska as a result of permafrost degradation and aggradation

NASA Astrophysics Data System (ADS)

Kanevskiy, M. Z.; Jorgenson, M. T.; Shur, Y.; O'Donnell, J.; Harden, J. W.; Fortier, D.

2012-12-01

Perennially frozen lacustrine sediments containing a large amount of ground ice comprise a significant part of the upper permafrost of the lowlands of west-central Alaska, including Koyukuk Flats and Innoko Flats. Study sites are located in the discontinuous permafrost zone, where permafrost was encountered mainly within uplifted peat plateaus. The upper part of studied sections is formed by frozen peat up to 3 m thick underlain by lacustrine silt, which is mostly ice-rich. Cryogenic structure of lacustrine sediments at different sites has common features: (1) prevalence of layered, braided, and reticulate cryostructures; (2) high variability in the ice content of sediments; (3) high density and low water content of soil aggregates separated by ice lenses. Volume of visible ice in silt reaches at places 40% and more. The thickness of ice lenses generally varies from 1 to 5 cm and occasionally reaches 10 cm. Remnants of peat plateaus are surrounded by unfrozen bogs and fens, formed as a result of thawing and settling of ice-rich lacustrine silt. Modern thermokarst scars initially form at places where ice-rich silt is not protected by a thick layer of organic material. Further development of thermokarst bogs includes lateral enlargement of thaw bulbs and collapsing of the margins of peat plateaus. Lacustrine silt within taliks is covered by woody peat accumulated under forests during the stage of permafrost plateau formation and then by aquatic sphagnum peat accumulated in taliks after collapse. We relate the formation of ice-rich lacustrine sediments to development of lake thermokarst, which affected ice-rich silty yedoma deposits during the transition from Pleistocene to Holocene. Terrain development in lacustrine lowlands of west-central Alaska includes five stages related to permafrost aggradation and degradation from the late Pleistocene to the present time: 1) formation of the ice-rich syngenetic permafrost (yedoma) during the late Pleistocene; 2) yedoma degradation in the yearly Holocene and formation of thaw lakes; 3) complete yedoma degradation under thaw lakes and refreezing of thawed sediments at elevated areas; 4) peat accumulation and freezing of sediments in thaw lake basins; and 5) new cycle of thermokarst and formation of taliks under thaw lakes, bogs and fens. Stages of terrain development of lacustrine lowlands since the Late Pleistocene

Quarternary Pollen Analysis in Secondary School Ecology

ERIC Educational Resources Information Center

Slater, F. M.

1972-01-01

Describes techniques for studying historic changes in climate by analysis of pollen preserved in peat bogs. Illustrates the methodology and data analysis techniques by reference to results from English research. (AL)

Nitrogen cycling in ombrotrophic peat bogs in the Czech Republic: Is microbial N-fixation occurring at atmospheric depositions of reactive N higher than 10 kg/ha/yr?

NASA Astrophysics Data System (ADS)

Novak, Martin; Jackova, Ivana; Cejkova, Bohuslava; Buzek, Frantisek; Curik, Jan; Stepanova, Marketa; Prechova, Eva; Veselovsky, Frantisek; Komarek, Arnost

2017-04-01

Biogeochemical cycling of carbon (C) and nitrogen (N) in peat bogs are coupled. Whereas at low pollution levels, reactive nitrogen (Nr, mainly nitrate- and ammonium-N) inputs may positively affect C storage, high Nr deposition may have a detrimental effect on C storage. We have previously reported N isotope systematics at two ombrotrophic peat bogs in the Czech Republic, receiving medium levels of Nr of about 10 kg/ha/yr via atmospheric deposition. Nitrogen of living Sphagnum was systematically heavier than N of the atmospheric input (p < 0.001), and close to the N isotope signature of atmospheric N2 (del15N-N2 of 0.0 per mil). We argued that even at medium Nr pollution, such as that in the Czech Republic, the amount of Nr in rainfall becomes minute toward the end of major precipitation events, possible triggering off microbial N-fixation. This process may be responsible for the del15N shift in Sphagnum from negative values of atmospheric deposition to the zero value of N2. In 2016, we conducted a laboratory study in which living Sphagnum from sites receiving annually slightly over 10 kg Nr/ha/yr via atmospheric deposition was incubated in an atmosphere enriched in 15N-N2. At the end of the incubation, we detected a 1 to 3 per mil increase in del15N of Sphagnum. Rinsing Sphagnum capitula in deionized water prior to the 15N-N2 incubation has led to a slight further increase in del15N of Sphagnum. Also in 2016, we monitored del15N of atmospheric deposition at three medium Nr-polluted peat bogs. Open-area precipitation had the following mean del 15N values: Uhlirska -6.1 per mil (NH4) and -6.2 per mil (NO3); Brumiste -1.7 per mil (NH4) and -3.4 per mil (NO3); Male Mechove Jezirko -3.3 per mil (NH4) and -3.9 per mil (NO3). At all sites, atmospheric Nr deposition was made up by NO3-N and NH4-N in a roughly 1.1 ratio. We found that N of winter-time deposition became isotopically extremely light (less than -10.0 per mil). During the growing season, del15N of total atmospheric input was higher, closer to 0.0 per mil, but still slightly lower than del15N of living Sphagnum. These data thus confirm a N isotope discrepancy between the N isotope signature of deposition and Sphagnum. In the paper, we will also discuss a mass balance discrepancy in long-term atmospheric N input and N storage at the Czech sites, determined for replicated, lead-210 dated peat cores. We took into consideration a 30 % contribution of horizontal deposition (mainly fog interception), which we had directly measured, to total Nr deposition. Still, the dated peat cores appeared to accumulate 30 to 60 % more N than the maximum estimated atmospheric Nr input (both estimates for the period 1900-2015). Preliminarily, we conclude that three independent lines of evidence indicate intermittent N-fixation even at medium Nr-polluted peat bogs in Central Europe.

Characterization of acid-tolerant H/CO-utilizing methanogenic enrichment cultures from an acidic peat bog in New York State.

PubMed

Bräuer, Suzanna L; Yashiro, Erika; Ueno, Norikiyo G; Yavitt, Joseph B; Zinder, Stephen H

2006-08-01

Two methanogenic cultures were enriched from acidic peat soil using a growth medium buffered to c. pH 5. One culture, 6A, was obtained from peat after incubation with H(2)/CO(2), whereas culture NTA was derived from a 10(-4) dilution of untreated peat into a modified medium. 16S rRNA gene clone libraries from each culture contained one methanogen and two bacterial sequences. The methanogen 16S rRNA gene sequences were 99% identical with each other and belonged to the novel "R-10/Fen cluster" family of the Methanomicrobiales, whereas their mcrA sequences were 96% identical. One bacterial 16S rRNA gene sequence from culture 6A belonged to the Bacteroidetes and showed 99% identity with sequences from methanogenic enrichments from German and Russian bogs. The other sequence belonged to the Firmicutes and was identical to a thick rod-shaped citrate-utilizing organism isolated from culture 6A, the numbers of which decreased when the Ti (III) chelator was switched from citrate to nitrilotriacetate. Bacterial clones from the NTA culture clustered in the Delta- and Betaproteobacteria. Both cultures contained thin rods, presumably the methanogens, as the predominant morphotype, and represent a significant advance in characterization of the novel acidiphilic R-10 family methanogens.

Controls on methane released through ebullition in peatlands affected by permafrost degradation

USGS Publications Warehouse

Klapstein, Sara J.; Turetsky, Merritt R.; McGuire, A. David; Harden, Jennifer W.; Czimczik, C.I.; Xu, Xiaomei; Chanton, J.P.; Waddington, James Michael

2014-01-01

Permafrost thaw in peat plateaus leads to the flooding of surface soils and the formation of collapse scar bogs, which have the potential to be large emitters of methane (CH4) from surface peat as well as deeper, previously frozen, permafrost carbon (C). We used a network of bubble traps, permanently installed 20 cm and 60 cm beneath the moss surface, to examine controls on ebullition from three collapse bogs in interior Alaska. Overall, ebullition was dominated by episodic events that were associated with changes in atmospheric pressure, and ebullition was mainly a surface process regulated by both seasonal ice dynamics and plant phenology. The majority (>90%) of ebullition occurred in surface peat layers, with little bubble production in deeper peat. During periods of peak plant biomass, bubbles contained acetate-derived CH4 dominated (>90%) by modern C fixed from the atmosphere following permafrost thaw. Post-senescence, the contribution of CH4 derived from thawing permafrost C was more variable and accounted for up to 22% (on average 7%), in the most recently thawed site. Thus, the formation of thermokarst features resulting from permafrost thaw in peatlands stimulates ebullition and CH4 release both by creating flooded surface conditions conducive to CH4 production and bubbling as well as by exposing thawing permafrost C to mineralization.

Excavating and loading equipment for peat mining

NASA Astrophysics Data System (ADS)

Mikhailov, A. V.; Zhigulskaya, A. I.; Yakonovskaya, T. B.

2017-10-01

Recently, the issues of sustainable development of Russian regions, related to ensuring energy security, are more urgent than ever. To achieve sustainable development, an integrated approach to the use of local natural resources is needed. Practically in all north regions of the Russian Federation, peat as a local natural resource is widespread, which has a practical application in the area of housing services. The paper presents the evaluation of technologies for open-pit peat mining, as well as analysis of technological equipment for peat production. Special attention is paid to a question of peat materials excavating and loading. The problem of equipment selection in a peat surface mine is complex. Many features, restrictions and criteria need to be considered. Use of low and ultra-low ground pressure excavators and low ground pressure front-end loaders with full-range tires to provide the necessary floatation in the peat bog environment is offered.

Biogeochemistry of aquatic humic substances in Thoreau's Bog, Concord, Massachusetts

USGS Publications Warehouse

McKnight, Diane M.; Thurman, E. Michael; Wershaw, Robert L.; Hemond, Herold

1985-01-01

Thoreau's Bog is an ombrotrophic floating—mat Sphagnum bog developed in a glacial kettlehole and surrounded by a red maple swamp. Concentrations of dissolved organic carbon in the porewater of the bog average 36 mg/L and are greatest near the surface, especially during late summer. This distribution suggest that the upper layer of living and dead Sphagnum and moderately humified peat is the major site of dissolved organic material production in the bog. The dissolved organic material consists mainly of aquatic fulvic acid (67%) and hydrophilic acids (20%); these organic acids control the pH (typically 4 or somewhat lower) of the bogwater. The elemental, amino acid, carbohydrate, and carboxylic acid contents of fulvic acid from the bog are similar to those of aquatic fulvic acid from the nearby Shawsheen River, although the phenolic hydroxyl content of fulvic acid from Thoreau's Bog is higher. The hydrophilic acids have greater amino acid, carbohydrate, and carboxylic acid contents than the fulvic acid, consistent with the hypothesis that hydrophilic acids are more labile intermediate compounds in the formation of fulvic acid.

Losses of Soil Carbon upon a Fire on a Drained Forested Raised Bog

NASA Astrophysics Data System (ADS)

Glukhova, T. V.; Sirin, A. A.

2018-05-01

We studied the consequences of a fire that affected 29 ha of a drained forested raised bog in Tver oblast, Central European Russia. The drainage network consisted of open 1-m-deep ditches with 60 to 160 m ditch spacing. The groundwater level (GWL) varied within the studied drained bog. We used the method of assessing the loss of soil carbon (C) based on the difference between the ash concentration in the burnt peat of the upper layer and underlying unburnt layers. The carbon loss was higher near the drainage ditches than in the sites remote from ditches. The sample median values of carbon loss (kg C/m2) were estimated at 0.37 near the drainage ditches and at 0.22 for the remote sites with a distance of 160 m between ditches. They increased to 2.23 and 0.79 near and far from the drainage ditches for 106 m ditch spacing, and ranged from 1.13 to 2.10 near the drainage ditches and were equal to 0.45 at the remote sites for 60 m ditch spacing. The maximum loss of C was at the bog margin with the 70-cm-deep GWL; the sample median was equal to 2.97 kg C/m2. The results obtained for C loss from the wildfire on the raised bog agree with the estimates obtained by other authors (1.45-4.90 kg C/m2) and confirm the importance of taking such loss into account in the estimates of the carbon budget of peat soils (Histosols).

Effects of rewetting on greenhouse gas emissions in different microtopes in a cut-over drained bog in Schleswig-Holstein, Germany

NASA Astrophysics Data System (ADS)

Vybornova, Olga; Pfeiffer, Eva-Maria; Kutzbach, Lars

2016-04-01

In peatlands, all biogeochemical processes and the amount of exported carbon and nitrogen compounds are strongly influenced by changes in the water table. Peatland drainage leads to increased peat oxidization and changes peatlands from carbon sinks to net carbon sources. Especially, the emissions of the important greenhouse gases (GHG) carbon dioxide, methane and nitrous oxide are increased due to drainage. The currently ongoing restoration in the bog Himmelmoor (N 53° 44'20", E 9° 51'00", Quickborn) with an extent of about 6 km2 one of the largest raised bogs in Schleswig-Holstein, offers the possibility to characterize and to document the development of the fluxes at different sites before, during and after rewetting, using a method of small-scale closed chambers. Six subsites with differing water level and land use were identified: an area that was rewetted 30 years ago with Sphagnum vegetation, an area rewetted in 2009, an area with on-going peat extraction, deep peat cutting ditches refilled with peat with and without Eriophorum angustifolium vegetation and a comparatively dry peat dam. We determined that in the course of years 2014-2015 the measured N2O and CO2 fluxes varied between -0,1 and 1,9 mg m-2 h-1 and between -0,12 and 1,09 g m-2 h-1, respectively, and the highest nitrous oxide as well as carbon dioxide fluxes are typical for the dry peat dam study site. The measured CH4 fluxes were between -1,8 and 22,7 mg m-2 h-1, where the highest rates were found on the area rewetted 30 years ago and on the peat cutting ditches with Eriophorum angustifolium. Accounting for the different global warming potentials (GWP) of the measured greenhouse gases, the annual GHG balance was calculated. Emissions from all study sites ranged between 5,2 and 36 t CO2-eq ha-1 year-1 and were dominated by high emissions of CO2 (2,5 up to 25,5 t CO2-eq ha-1 year-1). Highest emission rates were found at the dry peat dam site and at the area rewetted 30 years ago. The peat dams and piles are also strong N2O sources. The rewetted, vegetated microtopes are strong CH4 sources, whereas all other areas show insignificant CH4 fluxes. The annual GHG emissions in the area rewetted 30 years ago are at least triply as high as the rates of the extraction on-going area, thus demonstrating the long period needed for the establishment of a carbon balance that is similar to the pre-drainage situation.

Effects of permafrost thaw on nitrogen availability and plant nitrogen acquisition in Interior Alaska

NASA Astrophysics Data System (ADS)

Finger, R.; Euskirchen, E. S.; Turetsky, M.

2013-12-01

The degradation of ice-rich permafrost, which covers a large portion of Interior Alaska, typically leads to thermokarst and increases in soil saturation. As a result, conifer peat plateaus degrade and are often replaced by wet collapse scar bogs. This state change results in profound changes in regional hydrology, biogeochemical cycling, and plant community composition. Preliminary data suggest that permafrost thaw can increase surface soil inorganic nitrogen (IN) concentrations but it is still unknown whether these changes in nutrient availability are short-lived (pulse releases) and whether or not they impact collapse scar vegetation composition or productivity, particularly as collapse scars undergo succession with time-after-thaw. Therefore we are currently examining changes in plant community composition, N availability and plant N acquisition along three thermokarst gradients in Interior Alaska. Each gradient is comprised of a forested permafrost peat plateau, adjacent ecotones experiencing active permafrost degradation (including a collapsing forest canopy and a saturated moat), and a collapse scar bog where permafrost has completely degraded. We predicted that IN concentrations would be highest along the active thaw margin, and lowest in the peat plateau. We also predicted that IN concentrations would be positively related to shifts in vegetation community composition, nutrient use efficiency (NUE) and tissue 15N concentrations. Preliminary results have shown that IN concentrations increase in newer collapse scar features as well as with thaw depth. Our data also show a shift from feather moss and ericaceous shrub-dominate understories in the permafrost plateau to Sphagnum and sedge dominated thaw ecotone and bog communities. Further successional development of the collapse scar bog results in the reintroduction of small evergreen and deciduous shrubs as the peat mat develops. Over time, collapse scar succession and peat accumulation appears to lead to progressive N limitations, resulting in the dominance of plants with higher NUE. This likely has implications for plant litter quality, and could inhibit decomposition processes. We are collecting additional data to compare species-level NUE and nutrient resorption efficiency. We also will measure δ15N of aboveground plant organs, roots, soil, and pore water to explore sources of plant N, which we expect will influenced rooting depth as permafrost thaws as well as differences in mycorrhizal associations along our thaw gradient. Because thawing permafrost soils are anticipated to mobilize large amounts of N from soils, our results will improve our understanding of how permafrost thaw influences vegetation and soil N pools, soil N availability, and plant nutrition.

Parameter Calculation Technique for the Waste Treatment Facilities Using Naturally-Aerated Blocks in the Bog Ecosystems

NASA Astrophysics Data System (ADS)

Akhmed-Ogly, K. V.; Savichev, O. G.; Tokarenko, O. G.; Pasechnik, E. Yu; Reshetko, M. V.; Nalivajko, N. G.; Vlasova, M. V.

2014-08-01

Technique for the domestic wastewater treatment in the small residential areas and oil and gas facilities of the natural and man-made systems including a settling tank for mechanical treatment and a biological pond with peat substrate and bog vegetation for biological treatment has been substantiated. Technique for parameters calculation of the similar natural and man-made systems has been developed. It was proven that effective treatment of wastewater can be performed in Siberia all year round.

Branched GDGT-based paleotemperature reconstruction of the last 30,000 years in humid monsoon region of Southeast China

NASA Astrophysics Data System (ADS)

Wang, M.

2017-12-01

The use of bacterial branched glycerol dialkyl glycerol tetraethers (brGDGTs) to reconstruct mean annual air temperatures (MAATs) and environmental pH from soils has sparked significant interest in the terrestrial paleoclimate community. However, the reconstruction of these climate proxies from peat bogs is rare in monsoonal regions of the East Asia. This research was carried out on a core from the Shuizhuyang (SZY) peat bog located in Fujian Province. Branched GDGT (brGDGT) indexes were used for reconstructing the paleoclimate of the last 30 cal ka. The aim was to evaluate quantitatively the MAAT and pH values since the Last Glacial Maximum (LGM) in the subtropical zone of China. Results show that the CBT-MBT'-derived MAAT at MIS 3 is about 15.6 °C on average, which is followed by a significant fall at the LGM (11.7-12.1 °C). The temperature difference between the LGM and the present-day value is as high as 5.8 °C. The synchronous variation of biomarker and pollen proxies indicates that replacement of subtropical evergreen broadleaved forests by coldtolerant, deciduous broadleaved forests was driven by the significant drop in air temperature. Our results also indicate that the Younger Dryas event lasted from about 12.9 to about 11.3 cal ka, and cooling event at 3.2 cal ka in the late Holocene was detected, showing the sensitivity of peat bogs to rapid cooling. Our pH reconstructions indicate that the pH of the bog rose during Heinrich 1 and Bølling-Allerød periods, probably due to low precipitation, and were lowest in the Holocene thermal maximum between 8 ka and 2.5 ka, probably due to higher precipitation. The decoupling of reconstructed MAAT and pH during particularly deglaciation and YD periods supports the hypothesis that the variations in temperature and precipitation are not always synchronous.

Factors Controlling Diffusive CO2 Transport and Production in the Cedarburg Bog, Saukville, Wisconsin

NASA Astrophysics Data System (ADS)

Joynt, E.; Grundl, T.; Han, W. S.; Gulbranson, E. L.

2016-12-01

Wetlands are vital components of the carbon cycle containing an estimated 20-30% of the global soil carbon store. The Cedarburg Bog of southeastern Wisconsin contains multiple wetland types, including the southernmost string bog found in North America. Carbon dioxide (CO2) behavior in wetland systems respond to multiple interdependent variables that are collectively not well understood. Modeling CO2 behavior in wetland environments requires a detailed representation of these variables. In 2014 a LI-COR 8100A automated soil gas flux system was installed in the string bog, measuring CO2 concentration and flux. Groundwater data, soil temperature, and weather data (temperature, pressure, precipitation, etc.) were included to reveal correlations between soil CO2 flux/concentration and external forces. In 2015 field data were complemented with soil moisture data and depth profiles of pore water chemistry and stable carbon isotopes from peat and soil gas to discern source and evolution of CO2 at depth. Initial gaseous δ13C(CO2) average -18‰ and deplete overnight suggesting increasing microbial metabolic efficiency. δ13C soil microbial biomass measure roughly -21‰ to -22‰. LI-COR data show diurnal and seasonal trends; CO2 concentration builds overnight while flux increases during the day. CO2 flux magnitude and CO2 concentration range peak in mid-summer, but frequency of increased CO2 flux events varies seasonally each year. Flux averages 7.55 mgCO2/min-m2 during the day but reaches 530 mgCO2/min-m2. Increased atmospheric and soil temperatures and decreasing atmospheric pressure prelude increasing CO2 flux intensity, though correlation strengths vary. Water level may influence CO2 flux, but observations suggest a mobile peat surface with the water table. 2016 imagery from trail cameras will determine extent of peat/well casing movement with water level changes. Further interpretation of data trends will utilize HYDRUS-1D to quantify relationships under changing environmental conditions.

Characterization of the efficiency of sedimentation basins downstream of harvested peat bogs

NASA Astrophysics Data System (ADS)

Samson-Do, Myriam; St-Hilaire, André

2015-04-01

Peat harvesting is a very lucrative industry in the provinces of Quebec and New-Brunswick (Canada). Peat enters in many potting mix used for horticulture. However, harvesting this resource has some impacts on the environment. First, industries need to drain the peat bog to dry the superficial layer. Then, it is harvested with industrial vacuums and the underlying layer is allowed to dry. The drained water is laden with suspended sediments (mostly organic peat fibers) that may affect biota of the stream where it is discharged. To counter the problem, this water does not go directly on the stream but first flows through a sedimentation basin, built to reduce suspended sediment loads. This work focuses on characterizing and eventually modeling the efficiency of those sedimentation basins. Seven basins were studied in Rivière-du-Loup, St-Valère and Escoumins (Quebec, Canada). They each have a different ratio basin area/drained area (4.7 10-4 to 20.3 10-4). To continuously monitor the sediment loads (calculated from sediment concentrations and discharge) entering and leaving basins, a nephelometer and a level logger were installed in the water column upstream and downstream of sedimentation basins. Their trapping efficiency was measured during the ice-free period (May to October) and for each significant rain event, since it is known that the rain and subsequent runoff induce most of the peat transport in and out of the basin. Results show that the event efficiency decreases as the basin is filled up with trapped sediments. For one basin, the efficiency was 85August. Trapping efficiency can be used as a tool to estimate basin dimensions. This has been done for municipal sedimentation ponds that trap minerals and will be adapted to the current context, where the dominant sediment is organic.

Experimental warming differentially affects microbial structure and activity in two contrasted moisture sites in a Sphagnum-dominated peatland.

PubMed

Delarue, Frédéric; Buttler, Alexandre; Bragazza, Luca; Grasset, Laurent; Jassey, Vincent E J; Gogo, Sébastien; Laggoun-Défarge, Fatima

2015-04-01

Several studies on the impact of climate warming have indicated that peat decomposition/mineralization will be enhanced. Most of these studies deal with the impact of experimental warming during summer when prevalent abiotic conditions are favorable to decomposition. Here, we investigated the effect of experimental air warming by open-top chambers (OTCs) on water-extractable organic matter (WEOM), microbial biomasses and enzymatic activities in two contrasted moisture sites named Bog and Fen sites, the latter considered as the wetter ones. While no or few changes in peat temperature and water content appeared under the overall effect of OTCs, we observed that air warming smoothed water content differences and led to a decrease in mean peat temperature at the warmed Bog sites. This thermal discrepancy between the two sites led to contrasting changes in microbial structure and activities: a rise in hydrolytic activity at the warmed Bog sites and a relative enhancement of bacterial biomass at the warmed Fen sites. These features were not associated with any change in WEOM properties namely carbon and sugar contents and aromaticity, suggesting that air warming did not trigger any shift in OM decomposition. Using various tools, we show that the use of single indicators of OM decomposition can lead to fallacious conclusions. Lastly, these patterns may change seasonally as a consequence of complex interactions between groundwater level and air warming, suggesting the need to improve our knowledge using a high time-resolution approach. Copyright © 2015 Elsevier B.V. All rights reserved.

Methane flux from Minnesota Peatlands

NASA Astrophysics Data System (ADS)

Crill, P. M.; Bartlett, K. B.; Harriss, R. C.; Gorham, E.; Verry, E. S.; Sebacher, D. I.; Madzar, L.; Sanner, W.

1988-12-01

Northern (>40°N) wetlands have been suggested as the largest natural source of methane (CH4) to the troposphere. To refine our estimates of source strengths from this region and to investigate climatic controls on the process, fluxes were measured from a variety of Minnesota peatlands during May, June, and August 1986. Sites included forested and unforested ombrotrophic bogs and minerotrophic fens in and near the U.S. Department of Agriculture Marcell Experimental Forest and the Red Lake peatlands. Late spring and summer fluxes ranged from 11 to 866 mg CH4 m-2 d-1, averaging 207 mg CH4 m-2 d-1 overall. At Marcell Forest, forested bogs and fen sites had lower fluxes (averages of 77 ± 21 mg CH4 m-2 d-1 and 142 ± 19 mg CH4 m-2 d-1) than open bogs (average of 294 ± 30 mg CH4 m-2 d-1). In the Red Lake peatland, circumneutral fens, with standing water above the peat surface, produced more methane than acid bog sites in which the water table was beneath the moss surface (325 ± 31 and 102 ± 13 mg CH4 m-2 d-1, respectively). Peat temperature was an important control. Methane flux increased in response to increasing soil temperature. For example, the open bog in the Marcell Forest with the highest CH4 flux exhibited a 74-fold increase in flux over a three-fold increase in temperature. We estimate that the methane flux from all peatlands north of 40° may be on the order of 70 to 90 Tg/yr though estimates of this sort are plagued by uncertainties in the areal extent of peatlands, length of the CH4 producing season, and the spatial and temporal variability of the flux.

Species Identification of Archaeological Skin Objects from Danish Bogs: Comparison between Mass Spectrometry-Based Peptide Sequencing and Microscopy-Based Methods

PubMed Central

Brandt, Luise Ørsted; Schmidt, Anne Lisbeth; Mannering, Ulla; Sarret, Mathilde; Kelstrup, Christian D.; Olsen, Jesper V.; Cappellini, Enrico

2014-01-01

Denmark has an extraordinarily large and well-preserved collection of archaeological skin garments found in peat bogs, dated to approximately 920 BC – AD 775. These objects provide not only the possibility to study prehistoric skin costume and technologies, but also to investigate the animal species used for the production of skin garments. Until recently, species identification of archaeological skin was primarily performed by light and scanning electron microscopy or the analysis of ancient DNA. However, the efficacy of these methods can be limited due to the harsh, mostly acidic environment of peat bogs leading to morphological and molecular degradation within the samples. We compared species assignment results of twelve archaeological skin samples from Danish bogs using Mass Spectrometry (MS)-based peptide sequencing, against results obtained using light and scanning electron microscopy. While it was difficult to obtain reliable results using microscopy, MS enabled the identification of several species-diagnostic peptides, mostly from collagen and keratins, allowing confident species discrimination even among taxonomically close organisms, such as sheep and goat. Unlike previous MS-based methods, mostly relying on peptide fingerprinting, the shotgun sequencing approach we describe aims to identify the complete extracted ancient proteome, without preselected specific targets. As an example, we report the identification, in one of the samples, of two peptides uniquely assigned to bovine foetal haemoglobin, indicating the production of skin from a calf slaughtered within the first months of its life. We conclude that MS-based peptide sequencing is a reliable method for species identification of samples from bogs. The mass spectrometry proteomics data were deposited in the ProteomeXchange Consortium with the dataset identifier PXD001029. PMID:25260035

Sorption of radioiodide in an acidic, nutrient-poor boreal bog: insights into the microbial impact.

PubMed

Lusa, M; Bomberg, M; Aromaa, H; Knuutinen, J; Lehto, J

2015-05-01

Batch sorption experiments were conducted to evaluate the sorption behaviour of iodide and the microbial impact on iodide sorption in the surface moss, subsurface peat, gyttja, and clay layers of a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of iodide decreased as a function of sampling depth. The highest Kd values, 4800 L/Kg dry weight (DW) (geometric mean), were observed in the fresh surface moss and the lowest in the bottom clay (geometric mean 90 mL/g DW). In the surface moss, peat and gyttja layers, which have a high organic matter content (on average 97%), maximum sorption was observed at a pH between ∼ 4 and 5 and in the clay layer at pH 2. The Kd values were significantly lower in sterilized samples, being 20-fold lower than the values found for the unsterilized samples. In addition, the recolonization of sterilized samples with a microbial population from the fresh samples restored the sorption capacity of surface moss, peat and gyttja samples, indicating that the decrease in the sorption was due to the destruction of microbes and supporting the hypothesis that microbes are necessary for the incorporation of iodide into the organic matter. Anoxic conditions reduced the sorption of iodide in fresh, untreated samples, similarly to the effect of sterilization, which supports the hypothesis that iodide is oxidized into I2/HIO before incorporation into the organic matter. Furthermore, the Kd values positively correlated with peroxidase activity in surface moss, subsurface peat and gyttja layers at +20 °C, and with the bacterial cell counts obtained from plate count agar at +4 °C. Our results demonstrate the importance of viable microbes for the sorption of iodide in the bog environment, having a high organic matter content and a low pH. Copyright © 2015 Elsevier Ltd. All rights reserved.

Peat soil composition as indicator of plants growth environment

NASA Astrophysics Data System (ADS)

Noormets, M.; Tonutare, T.; Kauer, K.; Szajdak, L.; Kolli, R.

2009-04-01

Exhausted milled peat areas have been left behind as a result of decades-lasting intensive peat production in Estonia and Europe. According to different data there in Estonia is 10 000 - 15 000 ha of exhausted milled peat areas that should be vegetated. Restoration using Sphagnum species is most advantageous, as it creates ecological conditions closest to the natural succession towards a natural bog area. It is also thought that the large scale translocation of vegetation from intact bogs, as used in some Canadian restoration trials, is not applicable in most of European sites due to limited availability of suitable donor areas. Another possibility to reduce the CO2 emission in these areas is their use for cultivation of species that requires minimum agrotechnical measures exploitation. It is found by experiments that it is possible to establish on Vaccinium species for revegetation of exhausted milled peat areas. Several physiological activity of the plant is regulated by the number of phytohormones. These substances in low quantities move within the plant from a site of production to a site of action. Phytohormone, indole-3-acetic acid (IAA) is formed in soils from tryptophane by enzymatic conversion. This compound seems to play an important function in nature as result to its influence in regulation of plant growth and development. A principal feature of IAA is its ability to affect growth, development and health of plants. This compound activates root morphology and metabolic changes in the host plant. The physiological impact of this substance is involved in cell elongation, apical dominance, root initiation, parthenocarpy, abscission, callus formation and the respiration. The investigation areas are located in the county of Tartu (58˚ 22' N, 26˚ 43' E), in the southern part of Estonia. The soil of the experimental fields belongs according to the WRB soil classification, to the soils subgroups of Fibri-Dystric Histosols. The investigation areas were chosen by following criteria: (1) plantcover age; (2) cultivated plant species; (3) utilized agrotechnology; (4) comparisons between different factors were created by using natural growth areas of Vaccinaceae (natural bog area, Vaccinaceae growth area on mineral soil). For the investigation is important to choose areas with different age of plant covers, because according to plants age the surface of exhausted peat land will be covered in relation to the width of plants. The purpose of current article is to investigate the biological and chemical parameters co-influences in peat soil. Thus, the major interest is on the plant growth hormone indole-3-acetic acid distribution and dynamics in peat soil and dependence of plant cover, also its influence to the plants growth. Moreover, its contribution to yield and new growth area invasion will be discussed.

Greenhouse gas exchange of rewetted bog peat extraction sites and a Sphagnum cultivation site in northwest Germany

NASA Astrophysics Data System (ADS)

Beyer, C.; Höper, H.

2015-04-01

During the last decades an increasing area of drained peatlands has been rewetted. Especially in Germany, rewetting is the principal treatment on cutover sites when peat extraction is finished. The objectives are bog restoration and the reduction of greenhouse gas (GHG) emissions. The first sites were rewetted in the 1980s. Thus, there is a good opportunity to study long-term effects of rewetting on greenhouse gas exchange, which has not been done so far on temperate cutover peatlands. Moreover, Sphagnum cultivating may become a new way to use cutover peatlands and agriculturally used peatlands as it permits the economical use of bogs under wet conditions. The climate impact of such measures has not been studied yet. We conducted a field study on the exchange of carbon dioxide, methane and nitrous oxide at three rewetted sites with a gradient from dry to wet conditions and at a Sphagnum cultivation site in NW Germany over the course of more than 2 years. Gas fluxes were measured using transparent and opaque closed chambers. The ecosystem respiration (CO2) and the net ecosystem exchange (CO2) were modelled at a high temporal resolution. Measured and modelled values fit very well together. Annually cumulated gas flux rates, net ecosystem carbon balances (NECB) and global warming potential (GWP) balances were determined. The annual net ecosystem exchange (CO2) varied strongly at the rewetted sites (from -201.7 ± 126.8 to 29.7± 112.7g CO2-C m-2 a-1) due to differing weather conditions, water levels and vegetation. The Sphagnum cultivation site was a sink of CO2 (-118.8 ± 48.1 and -78.6 ± 39.8 g CO2-C m-2 a-1). The annual CH4 balances ranged between 16.2 ± 2.2 and 24.2 ± 5.0g CH4-C m-2 a-1 at two inundated sites, while one rewetted site with a comparatively low water level and the Sphagnum farming site show CH4 fluxes close to 0. The net N2O fluxes were low and not significantly different between the four sites. The annual NECB was between -185.5 ± 126.9 and 49.9 ± 112.8 g CO2-C m-2 a-1 at the rewetted sites and -115.8 ± 48.1 and -77 ± 39.8 g CO2-C m-2 a-1 at the Sphagnum cultivating site. The annual GWP100 balances ranged from -280.5 ± 465.2 to 644.5 ± 413.6 g CO2-eq. m-2 a-1 at the rewetted sites. In contrast, the Sphagnum farming site had a cooling impact on the climate in both years (-356.8 ± 176.5 and -234.9 ± 145.9 g CO2-C m-2 a-1). If the carbon exported through the harvest of the Sphagnum biomass and the additional CO2 emission from the decay of the organic material is considered, the NECB and GWP100 balances are near neutral. Peat mining sites are likely to become net carbon sinks and a peat accumulating ("growing") peatland within 30 years of rewetting, but the GWP100 balance may still be positive. A recommended measure for rewetting is to achieve a water level of a few centimetres below ground. Sphagnum farming is a climate-friendly alternative to conventional commercial use of bogs. A year-round constant water level of a few centimetres below ground level should be maintained.

Environmental and biogeochemical controls on N2 fixation in ombrotrophic peatlands

NASA Astrophysics Data System (ADS)

Zivkovic, T.; Moore, T. R.

2017-12-01

Northern peatlands have low atmospheric nitrogen (N) inputs and acquire N mostly via biological, microbially-driven N2-fixation. Little is known about rates and controls on N2-fixation in ombrotrophic bogs. We conducted two studies to test environmental and biogeochemical controls on N2-fixation. First, we used acetylene reduction assay (ARA) calibrated with 15N2 tracer to measure N2-fixation rates in three species of Sphagnum mosses along a hydrological gradient (beaver pond, hollow and hummock in bog margin and in bog) at Mer Bleue bog from June-October 2013 and May - November 2014. We tested the following controls: moisture availability, temperature, and PAR. The largest ARA rates throughout both seasons occurred in the pond in floating Sphagnum cuspidatum mats (50.3 ± 12.9 μmol m-2 d-1 Mean ± SE), which were up to 2.5 times larger than the rates found in the driest hummock site. There was a significant seasonal peak in both years in July and early August that coincided with the peak of the air temperature. In fact, 45% of the variance of N2 fixation rates over the two field seasons was explained by rain events, water table fluctuations and the surface peat temperature (multiple regression analysis, n = 539). Our results highlight the potential impact of climate change, namely negative effects due to potential droughts and positive effect of warming, on N2 fixation patterns in ombrotrophic peatlands. Secondly, we tested stoichiometric controls (Sphagnum tissue N and phosphorous (P) ratio) of N2-fixation. In a controlled environment, we selected eight study sites along a latitudinal gradient from temperate, boreal to subarctic zone in eastern Canada. We found that decreasing N:P ratio corresponded to increasing N2-fixation. N:P explained 65% of the variance in N2-fixation in hollows but only 20% in hummocks. Changes in neither N or P concentration alone explained the increase in N2-fixation better than N:P ratio. We interpret that the difference between hollows and hummocks results from the availability of moisture that further limits N2-fixation. When moisture is not a limiting factor, i.e. in hollows, N:P is the best predictor of N2-fixation in bogs.

Peatlands in a eutrophic world - assessing the state of a poor fen-bog transition in southern Ontario, Canada, after long term nutrient input and altered hydrological conditions

NASA Astrophysics Data System (ADS)

Berger, Sina; Gebauer, Gerhard; Blodau, Christian; Knorr, Klaus-Holger

2017-04-01

Peatlands are of vital importance for global carbon (C) cycling as they sequester and store enormous amounts of C. Major threats to peatlands are excessive supply of nutrients from the atmosphere as well as from surface water and groundwater. Up to this date our knowledge of long-term consequences of such excessive nutrient supply is limited. We are unsure about how long peatlands can maintain their functioning under such circumstances. We conducted a detailed study in a once ombrotrophic bog ecosystem (Wylde Lake peatland, Ontario, Canada), which is since the 19th century embedded in a eutrophic environment with intensive agriculture. Moreover, since AD 1954 the peatland borders a water reservoir which is strongly enriched with nutrients. Our objective was to elucidate to which extent the infiltration of nutrient from the peatland periphery can be buffered and whether the inner parts can maintain typical characteristics of a pristine bog. To achieve this goal, along a transect of study sites, we Pb-210- and Cs-137-dated peat cores and determined elements of peat using x-ray fluorescence (XRF). To calculate N input, nitrogen enrichment factors in the vegetation and abundances of stable N isotopes in the peat were determined through isotope ratio mass spectrometry (IRMS). Furthermore, we re-investigated the vascular plant species composition 31 years after a previous investigation and lastly, we sporadically measured greenhouse gas fluxes with chamber techniques. In the central part of the peatland we found great N input rates of 4.28±0.75 and 4.35±0.30 g N m-2 y-1, but even greater rates were found in the peatland fringe area (5.90±0.10 g N m-2 y-1). Also, all elements essential for plant growth were abundant in increased concentrations along all peat cores, especially near the bordering reservoir, presumably due to supply by the reservoir water. A more graminoid dominated vegetation in the wetter areas (near the reservoir) and a rapid increase of tree cover in drier areas (further away from the reservoir), both over a healthy Sphagnum carpet, as well as altered fluxes of CO2, CH4 and N2O indicate a transformation of the once ombrotrophic bog into a poor fen. Very much to our surprise the peatland did not seem to decay after long-term excessive nutrient load, instead it tremendously accelerated peat accumulation which led to maximum growth rates of up to 500 g C m-2 y-1. Peatland functioning in terms of carbon storage appeared to be maintained. Our study, which combines a great variety of methods and which provides detailed insights into various processes along peat profiles and vegetation cover, therefore contradicts numerous previous studies in which it was stated that long-term excessive supply of nutrients to peatlands would cause dying of Sphagnum mosses and hence, a decay and increased peat loss of the affected site already after one decade.

Greenhouse gas emissions from rewetted bog peat extraction sites and a Sphagnum cultivation site in Northwest Germany

NASA Astrophysics Data System (ADS)

Beyer, C.; Höper, H.

2014-03-01

During the last three decades, an increasing area of drained peatlands was rewetted. This was done with the objective to convert these sites from sources back to sinks or, at least, to much smaller sources of greenhouse gases (GHG). However, available data is still scarce, especially on the long-term climatic effects of rewetting of temperate bogs. Moreover, first field trials are established for Sphagnum cultivating (paludiculture) on wet bog sites and an assessment of the climate impact of such measures has not been studied yet. We conducted a field study on the exchange of carbon dioxide, methane and nitrous oxide at three rewetted sites with a gradient from dry to wet conditions and at a Sphagnum cultivation site in NW Germany over more than two years. Gas fluxes were measured using transparent and opaque closed chambers. The ecosystem respiration (CO2) and the net ecosystem exchange (CO2) were modelled in high time resolution using automatically monitored climate data. Measured and modelled values fit very well together (R2 between 0.88 and 0.98). Annually cumulated gas flux rates, net ecosystem carbon balances (NECB) and global warming potential (GWP) balances were determined. The annual net ecosystem exchange (CO2) varied strongly at the rewetted sites (from -201.7 ± 126.8 to 29.7 ± 112.7 g CO2-C m-2 a-1) due to different weather conditions, water level and vegetation. The Sphagnum cultivation site was a sink of CO2 (-118.8 ± 48.1 and -78.6 ± 39.8 g CO2-C m-2 a-1). The yearly CH4 balances ranged between 16.2 ± 2.2 and 24.2 ± 5.0 g CH4-C m-2 a-1 at two inundated sites, while one rewetted site with a comparatively low water level and the Sphagnum farming site show CH4 fluxes close to zero. The net N2O fluxes were low and not significantly different between the four sites. The annual NECB at the rewetted sites was between -183.8 ± 126.9 and 51.6 ± 112.8 g CO2-C m-2 a-1 and at the Sphagnum cultivating site -114.1 ± 48.1 and -75.3 ± 39.8 g CO2-C m-2 a-1. The yearly GWP100 balances ranged from -280.5 ± 465.2 to 644.5 ± 413.6 g CO2-eq. m-2 a-1 at the rewetted sites. In contrast, the Sphagnum farming site had a cooling impact on the climate in both years (-356.8 ± 176.5 and -234.9 ± 145.9 g CO2-C m-2 a-1). If the exported carbon through the harvest of the Sphagnum biomass and the additional CO2 emission from the decay of the organic material is considered, the NECB and GWP100 balances are near neutral. Peat mining sites are likely to become net carbon sinks and a peat accumulating ("growing") peatland within 30 years after rewetting, but the GWP100 balance may still be positive. A recommended measure for rewetting is to achieve a water level of a few centimetres below ground surface. Sphagnum farming is a climate friendly alternative to conventional commercial use of bogs. A year round constant water level of a few centimetres below ground level should be maintained.

Wildfire Health and Economic Impacts Case Study###

EPA Science Inventory

Since 2008 eastern North Carolina experienced 6 major wildfires, far exceeding the historic 50 year expected rate of return. Initiated by the lighting strikes, these fires spread across multiple feet deep, dry and extremely vulnerable peat bogs. The fires produced massive amounts...

ROUND LAKE WILDERNESS STUDY AREA, WISCONSIN.

USGS Publications Warehouse

Cannon, W.F.; Williams, Bradford B.

1984-01-01

The Round Lake Wilderness study area in Wisconsin was studied using geophysical and geochemical surveys, examination of a few bedrock exposures near the area (none are known within the area) and augering and testing of peat deposits. The only direct indication of potential mineral resource is about 760,000 tons of commercial quality peat contained in several bogs. Larger deposits of similar material are abundant closer to markets and although the peat in this area is classified as a demonstrated resource within an area of substantiated peat resource potential, it is considered to be of little importance. The study area lies within a belt of ancient volcanic rocks extending across northern Wisconsin in which several important copper, zinc, and lead deposits were discovered but no indication of such deposits was found within the area.

GPR attenuation analyses using spectral ratios of primary and multiple arrivals: examples from Welsh peat bogs

NASA Astrophysics Data System (ADS)

Booth, A.; Carless, D.; Kulessa, B.

2014-12-01

Ground penetrating radar (GPR) is widely applied to qualitative and quantitative interpretation of near-surface targets. Surface deployments of GPR most widely characterise physical properties in terms of some measure of GPR wavelet velocity. Wavelet amplitude is less-often considered, potentially due to difficulties in measuring this quantity: amplitudes are distorted by the anisotropic radiation pattern of antennas, and the ringy GPR wavelet can make successive events difficult to isolate. However, amplitude loss attributes could provide a useful means of estimating the physical properties of a target. GPR energy loss is described by the bandwidth-limited quality factor Q* which, for low-loss media, is proportional to the ratio of dielectric permittivity, ɛ, and electrical conductivity, σ. Comparing the frequency content of two arrivals yields an estimate of interval Q*, but only if they are sufficiently distinct. There may be sufficient separation between a primary reflection and its long-path multiple (i.e. a 'repeat path' of the primary reflection) therefore a dataset that is rich in multiples may be suitable for robust Q* analysis. The Q* between a primary and multiple arrival describes all frequency-dependent loss mechanisms in the interval between the free-surface and the multiple-generating horizon: assuming that all reflectivity is frequency-independent, Q* can be used to estimate ɛ and/or σ. We measure Q* according to the spectral ratio method, for synthetic and real GPR datasets. Our simulations are performed using the finite-difference algorithm GprMax, and represent our example data of GPR acquisitions over peat bogs. These data are a series of 100 MHz GPR acquisitions over sites in the Brecon Beacons National Park of South Wales. The base of the bogs (the basal peat/mineral soil contact) is often a strong multiple-generating horizon. As an example, data from Waun Ddu bog show these events lagging by ~75 ns: GPR velocity is measured here at 0.034 m/ns (relative ɛ of 77.9) and spectral ratios suggest Q* of 19.9 [-6.6 +19.4]. This Q* implies that the bulk σ of the bog is 21.7 [-10.7 +10.8] mS/m. Our measurements require in situ verification (e.g. comparison with co-located electrical resistivity profiles) but our method provides a promising addition to the suite of GPR analysis tools.

Carbon Fluxes in Dissolved and Gaseous Forms for a Restored Peatland in British Columbia, Canada

NASA Astrophysics Data System (ADS)

D'Acunha, B.; Johnson, M. S.; Lee, S. C.; Christen, A.

2016-12-01

Peatlands are wetlands where gross primary production exceeds organic matter decomposition causing an accumulation of partially decomposed matter, also called peat. These ecosystems can accumulate more carbon than tropical rainforests. However, dissolved and gaseous fluxes of carbon (as dissolved organic carbon (DOC), CO2 and methane (CH4)) must also be considered to determine if these ecosystems are net sinks or sources of greenhouse gases (GHGs) to the atmosphere, which depends in part on the environmental conditions and the state of the ecosystem. We conducted research in Burns Bog, Delta, BC, Canada, a raised domed peat bog located in the Fraser River Delta and one of the largest raised peat bogs on the west coast of the Americas, but which has been heavily impacted by a range of human activities. Currently, ecological restoration efforts are underway by a large-scale ditch blocking program, with the aim to re-establish a high water table. This is approached in partnership with research on the ecosystem services that the bog provides, including its role in a regional GHG inventory. Here we present data on ecosystem-scale fluxes of CO2 and CH4 determined by eddy covariance (EC) on a floating tower platform, and complementary data on (i) evasion fluxes of CO2, CH4 and nitrous oxide (N2O) from the water surface to the atmosphere, and (ii) the flux and composition of dissolved organic carbon in water draining Burns Bog. Concentrations of dissolved CO2, CH4 and N2O were determined by headspace equilibration, and evasion rates from the water surface were quantified and are used to estimate the role of the hydrosphere in the ecosystem-scale measurements. Water samples collected from five saturated areas in the flux tower footprint were analyzed for DOC concentrations and composition. Results indicated that, even though the whole system is a net C sink, the water surface behaved as a source of CO2 and CH4, and a sink for N2O throughout the study period. Drainage waters were high in DOC (> 30 mg L-1). DOC export was found to offset about 20% of the apparent net C uptake determined by EC, indicating that the EC system overestimates carbon accumulation by not accounting for DOC drainage.

Diversity and community structure of Archaea inhabiting the rhizoplane of two contrasting plants from an acidic bog.

PubMed

Cadillo-Quiroz, Hinsby; Yavitt, Joseph B; Zinder, Stephen H; Thies, Janice E

2010-05-01

Plant root exudates increase nutrient availability and influence microbial communities including archaeal members. We examined the archaeal community inhabiting the rhizoplane of two contrasting vascular plants, Dulichium arundinaceum and Sarracenia purpurea, from an acidic bog in upstate NY. Multiple archaeal 16S rRNA gene libraries showed that methanogenic Archaea were dominant in the rhizoplane of both plants. In addition, the community structure (evenness) of the rhizoplane was found markedly different from the bulk peat. The archaeal community in peat from the same site has been found dominated by the E2 group, meanwhile the rhizoplane communities on both plants were co-dominated by Methanosarcinaceae (MS), rice cluster (RC)-I, and E2. Complementary T-RFLP analysis confirmed the difference between bulk peat and rhizoplane, and further characterized the dominance pattern of MS, RC-I, and E2. In the rhizoplane, MS was dominant on both plants although as a less variable fraction in S. purpurea. RC-I was significantly more abundant than E2 on S. purpurea, while the opposite was observed on D. arundinaceum, suggesting a plant-specific enrichment. Also, the statistical analyses of T-RFLP data showed that although both plants overlap in their community structure, factors such as plant type, patch location, and time could explain nearly a third of the variability in the dataset. Other factors such as water table, plant replicate, and root depth had a low contribution to the observed variance. The results of this study illustrate the general effects of roots and the specific effects of plant types on their nearby archaeal communities which in bog-inhabiting plants were mainly composed by methanogenic groups.

Molybdenum-Based Diazotrophy in a Sphagnum Peatland in Northern Minnesota

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warren, Melissa J.; Lin, Xueju; Gaby, John C.

We present that Microbial N 2 fixation (diazotrophy) represents an important nitrogen source to oligotrophic peatland ecosystems, which are important sinks for atmospheric CO 2 and are susceptible to the changing climate. The objectives of this study were (i) to determine the active microbial group and type of nitrogenase mediating diazotrophy in an ombrotrophic Sphagnum-dominated peat bog (the S1 peat bog, Marcell Experimental Forest, Minnesota, USA); and (ii) to determine the effect of environmental parameters (light, O 2, CO 2, and CH 4) on potential rates of diazotrophy measured by acetylene (C 2H 2) reduction and 15N 2incorporation. A molecularmore » analysis of metabolically active microbial communities suggested that diazotrophy in surface peat was primarily mediated by Alphaproteobacteria (15N 2 was suppressed 90% by O 2 and 55% by C 2H 2 and was unaffected by CH 4 and CO 2 amendments. These results suggest that peatland diazotrophy is mediated by a combination of C 2H 2-sensitive and C 2H 2-insensitive microbes that are more active at low concentrations of O 2 and show similar activity at high and low concentrations of CH 4. Importance: Previous studies indicate that diazotrophy provides an important nitrogen source and is linked to methanotrophy in Sphagnum-dominated peatlands. However, the environmental controls and enzymatic pathways of peatland diazotrophy, as well as the metabolically active microbial populations that catalyze this process, remain in question. In conclusion, our findings indicate that oxygen levels and photosynthetic activity override low nutrient availability in limiting diazotrophy and that members of the Alphaproteobacteria (Rhizobiales) catalyze this process at the bog surface using the molybdenum-based form of the nitrogenase enzyme.« less

Molybdenum-Based Diazotrophy in a Sphagnum Peatland in Northern Minnesota

DOE PAGES

Warren, Melissa J.; Lin, Xueju; Gaby, John C.; ...

2017-06-30

We present that Microbial N 2 fixation (diazotrophy) represents an important nitrogen source to oligotrophic peatland ecosystems, which are important sinks for atmospheric CO 2 and are susceptible to the changing climate. The objectives of this study were (i) to determine the active microbial group and type of nitrogenase mediating diazotrophy in an ombrotrophic Sphagnum-dominated peat bog (the S1 peat bog, Marcell Experimental Forest, Minnesota, USA); and (ii) to determine the effect of environmental parameters (light, O 2, CO 2, and CH 4) on potential rates of diazotrophy measured by acetylene (C 2H 2) reduction and 15N 2incorporation. A molecularmore » analysis of metabolically active microbial communities suggested that diazotrophy in surface peat was primarily mediated by Alphaproteobacteria (15N 2 was suppressed 90% by O 2 and 55% by C 2H 2 and was unaffected by CH 4 and CO 2 amendments. These results suggest that peatland diazotrophy is mediated by a combination of C 2H 2-sensitive and C 2H 2-insensitive microbes that are more active at low concentrations of O 2 and show similar activity at high and low concentrations of CH 4. Importance: Previous studies indicate that diazotrophy provides an important nitrogen source and is linked to methanotrophy in Sphagnum-dominated peatlands. However, the environmental controls and enzymatic pathways of peatland diazotrophy, as well as the metabolically active microbial populations that catalyze this process, remain in question. In conclusion, our findings indicate that oxygen levels and photosynthetic activity override low nutrient availability in limiting diazotrophy and that members of the Alphaproteobacteria (Rhizobiales) catalyze this process at the bog surface using the molybdenum-based form of the nitrogenase enzyme.« less

Using Optical Oxygen Sensors and Injection Experiments to Determine in situ Microbial Rate Constants for Methane Oxidation and Heterotrophic Respiration in a Boreal Bog and Fen

NASA Astrophysics Data System (ADS)

Waldo, N.; Moorberg, C.; Waldrop, M. P.; Turetsky, M. R.; Neumann, R. B.

2015-12-01

Wetlands are the largest natural source of methane to the atmosphere, and play a key role in feedback cycles to climate change. In recognition of this, many researchers are developing process-based models of wetland methane emissions at various scales. In these models, the three key biogeochemical reactions are methane production, methane oxidation, and heterotrophic respiration, and they are modeled using Michaelis-Menten kinetics. The majority of Michaelis-Menten rate constants used in models are based on experiments involving slurries of peat incubated in vials. While these slurries provide a highly controlled setting, they are different from in situ conditions in multiple ways; notably they lack live plants and the centimeter-scale heterogeneities that exist in the field. To determine rate constants in a system more representative of in situ conditions, we extracted peat cores intact from a bog and fen located in the Bonanza Creek Experimental Forest near Fairbanks, Alaska and part of the Alaska Peatland Experiment (APEX) research program. Into those cores we injected water with varying concentrations of methane and oxygen at multiple depths. We used planar oxygen sensors installed on the peat cores to collect high resolution, two dimensional oxygen concentration data during the injections and used oxygen consumption rates under various conditions to calculate rate constants. Results were compared to a similar but smaller set of injection experiments conducted against planar oxygen sensors installed in the bog. Results will inform parametrization of microbial processes in wetland models, improving estimates of methane emissions both under current climate conditions and in the future.

Ecosystem and physiological controls over methane production in northern wetlands

NASA Technical Reports Server (NTRS)

Valentine, David W.; Holland, Elisabeth A.; Schimel, David S.

1994-01-01

Peat chemistry appears to exert primary control over methane production rates in the Canadian Northern Wetlands Study (NOWES) area. We determined laboratory methane production rate potentials in anaerobic slurries of samples collected from a transect of sites through the NOWES study area. We related methane production rates to indicators of resistance to microbial decay (peat C: N and lignin: N ratios) and experimentally manipulated substrate availability for methanogenesis using ethanol (EtOH) and plant litter. We also determined responses of methane production to pH and temperature. Methane production potentials declined along the gradient of sites from high rates in the coastal fens to low rates in the interior bogs and were generally highest in surface layers. Strong relationships between CH4 production potentials and peat chemistry suggested that methanogenesis was limited by fermentation rates. Methane production at ambient pH responded strongly to substrate additions in the circumneutral fens with narrow lignin: N and C: N ratios (delta CH4/delta EtOH = 0.9-2.3 mg/g) and weakly in the acidic bogs with wide C: N and lignin: N ratios (delta CH4/delta EtOH = -0.04-0.02 mg/g). Observed Q(sub 10) values ranged from 1.7 to 4.7 and generally increased with increasing substrate availability, suggesting that fermentation rates were limiting. Titration experiments generally demonstrated inhibition of methanogenesis by low pH. Our results suggest that the low rates of methane emission observed in interior bogs during NOWES likely resulted from pH and substrate quality limitation of the fermentation step in methane production and thus reflect intrinsically low methane production potentials. Low methane emission rates observed during NOWES will likely be observed in other northern wetland regions with similar vegetation chemistry.

A carbon accumulation maximum during the Medieval Climate Anomaly in the world’s biggest bog, Siberia

NASA Astrophysics Data System (ADS)

Beilman, D.; MacDonald, G. M.

2009-12-01

The West Siberia Lowland is the most carbon-rich northern wetland region, holding an important portion of total northern peatland carbon (70 Gt of 270-450 Gt C) mainly in the southern lowland (44 Gt) in very large peatlands. The largest of these, the Great Vasyugan Bog complex, spans 63,252 km2 and alone holds ~11 Gt C. Our previous work has shown that recent-past growth of WSL peat C pool has been greatest in southern WSL in large peatlands close to the southern limit of peatland distribution. In this study, we investigate a Great Vasyugan site to investigate peat carbon sensitivity in two ways: 1) assess past changes in vegetation, species-specific 13C geochemistry, and rate of carbon accumulation relative to recent-past climate variation, and 2) assess the relative lability of this deep peat C through laboratory incubations. Carbon accumulation over the last 2000 years, a period of relatively consistent vegetation and litter inputs but variable local hydrology, reached a maximum between 1150 and 1350 AD during Medieval Climate Anomaly conditions. A carbon accumulation minimum occurred between about 1350 and 1550 AD. Regardless of depth, age, or rate of carbon burial, deep peat from between 30 and 230 cm below the surface showed a similar rate of potential aerobic respiration that changed little over 42 days of incubation. Taken together, these data suggest that in some peatlanlds warmer and hydrologically-variable conditions can promote long-term belowground carbon storage.

Characterisation of VOC, SVOC, and PM emissions from peat burnt in laboratory simulations

EPA Science Inventory

Peat, or organic soil, is a vast store of organic carbon, widely distributed from polar temperate to equatorial regions. Drainage for agriculture and drought are drying vast areas of peat, exposing it to increasing fire risk, which may be exacerbated by climate change. This has ...

A comparison of lead pollution record in Sphagnum peat with known historical Pb emission rates in the British Isles and the Czech Republic

NASA Astrophysics Data System (ADS)

Novak, Martin; Erel, Yigal; Zemanova, Leona; Bottrell, Simon H.; Adamova, Marie

Vertical Pb concentration gradients and isotope ratios ( 206Pb/ 207Pb, 208Pb/ 207Pb) are reported for five 210Pb-dated Sphagnum peat profiles. The studied peat bogs are in the British Isles (Thorne Moors, England; Mull, Scotland; and Connemara, Eire) and central Europe (Ocean, northern Czech Republic; Rybarenska slat, southern Czech Republic). Both the U.K. and the Czech Republic experienced maximum Pb emissions from Ag-Pb smelting around 1880. Pb emissions from coal burning peaked in 1955 in the U.K. and in the 1980s in the Czech Republic. In both countries, use of alkyl-lead additives to gasoline resulted in large Pb emissions between 1950 and 2000. We hypothesized that peaks in Pb emissions from smelting, coal burning and gasoline burning, respectively, should be mirrored in the peat profiles. However, a more complicated pattern emerged. Maximum annual Pb accumulation rates occurred in 1870 at Ocean, 1940 at Thorne Moors, 1988 at Rybarenska slat, and 1990 at Mull and Connemara. Atmospheric Pb inputs decreased in the order Thorne Moors ≥ Ocean > Rybarenska slat > Mull > Connemara. The Ocean bog was unique in the central European region in that its maximum Pb pollution dated back to the 19th century and coincided with maximum Pb smelting at Freiberg and Pribram. In contrast, numerous previously studied sites showed no Pb accumulation maximum in the 19th century, but increasing pollution until the 1980s. It remains unclear why Ocean did not record the regional peak in Pb emissions caused by high coal and gasoline burning around 1980, while an array of nearby bogs studied previously did record the 1980 coal/gasoline peak, but no 1880 smelting peak. Mean 206Pb/ 207Pb ratios of potential pollution sources were 1.07 and 1.11 for gasoline, 1.17 and 1.17 for local ores, and 1.18 and 1.19 for coal in the U.K. and the Czech Republic, respectively. The calculated percentages of gasoline-derived Pb in peat (≤55% for the British Isles and ≤63% for the Czech Republic) were surprisingly low. An explanation for the low percentage of gasoline-derived Pb in peat can be more easily found for the Czech sites (until 1989 Czechoslovakia was the third largest lignite producer in the world). Regional differences in deposition rates of gasoline-derived Pb in the U.K. need further study.

Mycobacterium minnesotense sp. nov., a photochromogenic bacterium isolated from sphagnum peat bogs.

PubMed

Hannigan, Geoffrey D; Krivogorsky, Bogdana; Fordice, Daniel; Welch, Jacqueline B; Dahl, John L

2013-01-01

Several intermediate-growing, photochromogenic bacteria were isolated from sphagnum peat bogs in northern Minnesota, USA. Acid-fast staining and 16S rRNA gene sequence analysis placed these environmental isolates in the genus Mycobacterium, and colony morphologies and PCR restriction analysis patterns of the isolates were similar. Partial sequences of hsp65 and dnaJ1 from these isolates showed that Mycobacterium arupense ATCC BAA-1242(T) was the closest mycobacterial relative, and common biochemical characteristics and antibiotic susceptibilities existed between the isolates and M. arupense ATCC BAA-1242(T). However, compared to nonchromogenic M. arupense ATCC BAA-1242(T), the environmental isolates were photochromogenic, had a different mycolic acid profile and had reduced cell-surface hydrophobicity in liquid culture. The data reported here support the conclusion that the isolates are representatives of a novel mycobacterial species, for which the name Mycobacterium minnesotense sp. nov. is proposed. The type strain is DL49(T) (=DSM 45633(T) = JCM 17932(T) = NCCB 100399(T)).

Pattern of large raised bog formation in the South-Eastern Baltic Region during the Holocene: the case of Kaliningrad oblast

NASA Astrophysics Data System (ADS)

Napreenko-Dorokhova, T. V.; Napreenko, M. G.; Lisitzin, A. P.

2017-08-01

The results of complex investigations that have been carried out since 2007 in large bog ecosystems (Zehlau, Bolshoe Mokhovoe, and Koz'e) located in Kaliningrad oblast in two largest landscape areas, glaciolacustrine plains in the central part of the region and coastal lowlands of the southern coast of Curonian Lagoon and the delta of the Neman River, are presented. It is established that the intensive development of mires and their transition to the raised bog stage occurred in the territory of Kaliningrad oblast later than in most of the forest zone in European Russia, where this process was noted as early as during the Atlantic. On the glaciolacustrine flat plains in the central part of Kaliningrad oblast, where there were no deep depressions, the mire formation process was manifested weakly for a long time. A colder and more humid climate, which is a condition necessary for the raised bog peat accumulation and rapid expansion of bogs to the adjacent forest area, occurred only in the Subatlantic.

The Effect of Long-term Nutrient Addition on Peat Properties in an Ombrotrophic Bog

NASA Astrophysics Data System (ADS)

Moore, T. R.; Bubier, J. L.; Knorr, K. H.; Roy, C.

2017-12-01

Atmospheric inputs of nutrients, particularly N and P, to ecosystems have increased and may have a significant effect on nutrient-deficient peatlands such as bogs. At the Mer Bleue ombrotrophic bog near Ottawa, Canada, we have conducted an experiment over 10 to 20 years by adding 1.6 to 6.4 g N m-2 yr-1 (as NH4NO3), with/without 6 g P m-2 yr-1 (as K phosphate), to evaluate the effect of increased inputs on ecosystem functions. Increased N and P amendment has changed the vegetation from a mixed shrub-Sphagnum community into one dominated by shrubs with the disappearance of mosses, with changes in plant production and litter input. The largest N and P amendments have resulted in an increase in bulk density at 0-10 cm and a lowering of the peat surface by 10 to 20 cm, creating an effective rise in the water table and an increase in CH4 emission from 15 to 50 mg m-2 d-1. Peat cores to a depth of 40 cm were collected after 10 to 15 yr of amendment and showed little change in soil pH (range 4.1 to 4.5). There were substantial increases in the concentration of N and P in the peat (8 to 14 and 0.5 to 1.5 mg g-1, respectively) and general decreases in Ca and Mg concentration. The von Post humification index increased by about 1 unit in the heavily fertilized plots, with shrub leaves replacing Sphagnum as the primary litterfall. FTIR analysis of the 0-20 cm peat showed significant increases in abundance of phenolic+aliphatic, aromatic, and carboxylic relative to polysaccharide components, revealed by the following ratios of absorbance at the respective wavenumbers: 1420/1090 cm-1, 0.41 to 0.45; 1510/1090 cm-1, 0.23 to 0.30; 1630/1090 cm-1, 0.53 to 0.65; and 1720/1090 cm-1, 0.44 to 0.48, respectively. Laboratory incubations of peat samples showed that potential rates of aerobic CH4 consumption were unaffected by nutrient treatment, apart from position relative to the water table, whereas potential rates of anaerobic CH4 production near the water table increased under the P amendment. Potential rates of aerobic CO2 production generally decreased with depth in the cores, but were not strongly related to decomposition properties (e.g. Von Post, FTIR). This study shows the profound effect of increased N and P addition on the vegetation composition, carbon cycling and peat chemical properties and decomposability of this ombrotrophic mire.

No limits to peat bog growth? Transport and thermodynamic constraints on anaerobic organic matter decomposition

NASA Astrophysics Data System (ADS)

Blodau, C.; Julia, B.; Siems, M.

2009-05-01

In diffusion dominated systems, for which many thick peat deposits provide a model, slowness of transport and lack of free energy may pose a limit to methanogenic decomposition of organic matter and ultimately to closing the carbon cycle. To test this hypothesis we (I) conducted controlled column experiments with homogenized peat over an 18 month period, (II) investigated transport, in situ respiration pathways, rates and thermodynamic conditions in a nothern peatland, and (III) modelled depth profiles of CO2 and CH4 in the deposits. Vertical transport in the peatland was dominated by diffusion leading to the buildup of DIC and CH4 with depth (5500 µmol L 1 DIC, 500 µmol L 1 CH4). Highest DIC and CH4 production rates occurred close to the water table (decomposition constant kd ~10-3 to 10 4 a-1) and decreased to about kd = 10-7 a-1. The accumulation of metabolic end-products diminished in situ energy yields of acetoclastic methanogenesis to the threshold for microbially mediated processes (-20 to -25 kJ mol-1 CH4). The methanogenic precursor acetate also accumulated (150 µmol L 1). In line with these findings, CH4 was formed by hydrogenotrophic methanogenesis at Gibbs free energies of 35 to 40 kJ mol-1 CH4. This was indicated by an isotopic fractionation αCO2-CH4 of 1.069 to 1.079. Fermentative degradation of acetate, propionate and butyrate attained Gibbs free energies close to 0 kJ mol-1 substrate. In peat columns with homogenenous peat-sand mixtures of 50%, 15% and 5% dry weight, steady state CO2 production also decreased from about 10 to 0 nmol cm-3 d-1 and of CH4 from 1 to 0 nmol cm-3 d-1 with depth. Very similar depth profiles of concentrations and volumetric rates developed near endproduct thresholds of 600µmol CH4 and 10 mmol L-1 CO2, despite the differences in organic matter content. The modeling exercise showed that a consistent development of CH4 concentration profiles over time in the columns could only be accomplished with rates of acetoclastic methanogenesis decreasing to 0 near a critical Gibbs free energy of about -27 KJ mol-1. The results thus suggest that, even in absence of inorganic electron acceptors, respiration rates in peat bogs are likely higher near the redox interface to the atmosphere due to lower respiration endproduct concentrations. Similar effects ensue when rates of transport are elevated or pools of CO2 and CH4 are eliminated. With decomposition being constrained, peat bog growth may occur longer than previously thought.

Dynamic Vertical Profiles of Peat Porewater Chemistry in a Northern Peatland

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffiths, Natalie A.; Sebestyen, Stephen D.

We measured pH, cations, nutrients, and total organic carbon (TOC) over 3 years to examine weekly to monthly variability in porewater chemistry depth profiles (0–3.0 m) in an ombrotrophic bog in Minnesota, USA. We also compared temporal variation at one location to spatial variation in depth profiles at 16 locations across the bog. Most solutes exhibited large gradients with depth. pH increased by two units and calcium concentrations increased over 20 fold with depth, and may reflect peatland development from minerotrophic to ombrotrophic conditions. Ammonium concentrations increased almost 20 fold and TOC concentrations decreased by half with depth, and thesemore » patterns likely reflect mineralization of peat or decomposition of TOC. There was also considerable temporal variation in the porewater chemistry depth profiles. Ammonium, soluble reactive phosphorus, and potassium showed greater temporal variation in near-surface porewater, while pH, calcium, and TOC varied more at depth. This variation demonstrates that deep peat porewater chemistry is not static. Lastly, temporal variation in solute chemistry depth profiles was greater than spatial variation in several instances, especially in shallow porewaters. In conclusion, characterizing both temporal and spatial variability is necessary to ensure representative sampling in peatlands, especially when calculating solute pools and fluxes and parameterizing process-based models.« less

Dynamic Vertical Profiles of Peat Porewater Chemistry in a Northern Peatland

DOE PAGES

Griffiths, Natalie A.; Sebestyen, Stephen D.

2016-10-14

We measured pH, cations, nutrients, and total organic carbon (TOC) over 3 years to examine weekly to monthly variability in porewater chemistry depth profiles (0–3.0 m) in an ombrotrophic bog in Minnesota, USA. We also compared temporal variation at one location to spatial variation in depth profiles at 16 locations across the bog. Most solutes exhibited large gradients with depth. pH increased by two units and calcium concentrations increased over 20 fold with depth, and may reflect peatland development from minerotrophic to ombrotrophic conditions. Ammonium concentrations increased almost 20 fold and TOC concentrations decreased by half with depth, and thesemore » patterns likely reflect mineralization of peat or decomposition of TOC. There was also considerable temporal variation in the porewater chemistry depth profiles. Ammonium, soluble reactive phosphorus, and potassium showed greater temporal variation in near-surface porewater, while pH, calcium, and TOC varied more at depth. This variation demonstrates that deep peat porewater chemistry is not static. Lastly, temporal variation in solute chemistry depth profiles was greater than spatial variation in several instances, especially in shallow porewaters. In conclusion, characterizing both temporal and spatial variability is necessary to ensure representative sampling in peatlands, especially when calculating solute pools and fluxes and parameterizing process-based models.« less

Methane ebullition fluxes from northern peatlands: initial observations from four sites of contrasting vegetation type in Caribou Bog, ME

NASA Astrophysics Data System (ADS)

Slater, L. D.; Comas, X.; Mumford, K. G.; Reeve, A. S.; Varner, R. K.; Chen, X.; Wright, W.; Wright, J.; Molnar, I. L.; Krol, M.

2017-12-01

The contribution of peatlands to the atmospheric CH4 burden remains unclear in large part due to incomplete understanding of the ebullition pathway. Oxidation of dissolved methane reduces the release of methane by diffusion, but the transit time of bubbles released via ebullition is too short for extensive oxidation to occur, i.e. ebullition releases increase the greenhouse gas potential of peatlands. We are working to couple innovative strategies for ebullition monitoring with a physical model describing gas transport in terms of the mechanical properties of the peat. This integration of measurement and modeling will permit a fundamental step forward towards a more quantitative understanding of CH4 ebullition from peatlands. Sampling and sensor installation have been performed in Caribou Bog, a multi-unit peatland located in Maine (USA) where an extensive database accounting for a decade of research is already available from previous work examining methane dynamics. Multi-depth gas trap and moisture probe arrays have been installed at four sites selected based on contrasting vegetation type and peat basin depth determined from extensive ground penetrating radar surveys. Hydraulic head measurements have also been acquired on multi-level piezometers designed to capture transient signals associated with gas transport. Cores and initial field observations acquired in summer 2017 confirm that the physical properties of the peat vary markedly between the sites and influence gas storage and release. An existing ebullition model describing gas bubble expansion is being coupled with an invasion percolation approach to describe the transport of CH4 between multiple peat layers by both diffusion in the pore water and ebullition between layers. Although the proposed model does not explicitly incorporate the geomechanical properties of peat, model predictions for maximum gas contents are being compared with key measurable geomechanical properties (including measured capillary drainage curves for peat) that may control ebullition.

How do peat type, sand addition and soil moisture influence the soil organic matter mineralization in anthropogenically disturbed organic soils?

NASA Astrophysics Data System (ADS)

Säurich, Annelie; Tiemeyer, Bärbel; Don, Axel; Burkart, Stefan

2017-04-01

Drained peatlands are hotspots of carbon dioxide (CO2) emissions from agriculture. As a consequence of both drainage induced mineralization and anthropogenic sand mixing, large areas of former peatlands under agricultural use contain soil organic carbon (SOC) at the boundary between mineral and organic soils. Studies on SOC dynamics of such "low carbon organic soils" are rare as the focus of previous studies was mainly either on mineral soils or "true" peat soil. However, the variability of CO2 emissions increases with disturbance and therefore, we have yet to understand the reasons behind the relatively high CO2 emissions of these soils. Peat properties, soil organic matter (SOM) quality and water content are obviously influencing the rate of CO2 emissions, but a systematic evaluation of the hydrological and biogeochemical drivers for mineralization of disturbed peatlands is missing. With this incubation experiment, we aim at assessing the drivers of the high variability of CO2 emissions from strongly anthropogenically disturbed organic soil by systematically comparing strongly degraded peat with and without addition of sand under different moisture conditions and for different peat types. The selection of samples was based on results of a previous incubation study, using disturbed samples from the German Agricultural Soil Inventory. We sampled undisturbed soil columns from topsoil and subsoil (three replicates of each) of ten peatland sites all used as grassland. Peat types comprise six fens (sedge, Phragmites and wood peat) and four bogs (Sphagnum peat). All sites have an intact peat horizon that is permanently below groundwater level and a strongly disturbed topsoil horizon. Three of the fen and two of the bog sites have a topsoil horizon altered by sand-mixing. In addition the soil profile was mapped and samples for the determination of soil hydraulic properties were collected. All 64 soil columns (including four additional reference samples) will be installed in a microcosm system under a constant temperature of 10°C. The water-saturated soil columns will be drained via suction plates at the bottom of the columns by stepwise increase of the suction. The head space of the soil columns will be permanently flushed with moistened synthetic air and CO2 concentrations will be measured via online gas chromatography. First results will be presented.

Holocene palaeohydrological history of the Tǎul Muced peat bog (Northern Carpathians, Romania) based on testate amoebae (Protozoa) and plant macrofossils

NASA Astrophysics Data System (ADS)

Cosmin Diaconu, Andrei; Feurdean, Angelica; Lamentowicz, Mariusz; Gałka, Mariusz; Tanţǎu, Ioan

2016-04-01

Knowledge of past local vs. regional hydro-climate variability is a priority in climate research. This is because ecosystems and human depend on local climatic conditions and the magnitude of these climate changes is more variable at local and regional rather than at global scales. Ombrotrophic bogs are highly suitable for hydro-climate reconstructions as they are entirely dependent on the water from precipitation. We used stratigraphy, radiocarbon dating, testate amoebae (TA) and plant macrofossils on a peat profile from an ombrotrophic bog (Tǎul Muced) located in the Biosphere Reserve of the Rodna National Park Romania. We performed quantitative reconstruction of the depth to water table (DWT) and pH over the last 8000 years in a continental area of CE Europe. We identified six main stages in the development of the bog based on changes in TA assemblages in time. Wet conditions and pH between 2 and 4.5 were recorded between 4600-2750 and 1300-400 cal. yr BP, by the occurrence of Archerella flavum, Amphitrema wrightianum and Hyalosphenia papilio. This was associated to a local vegetation primarily composed of Sphagnum magellanicum and S. angustifolium. Dry stages and pH of 2.5 to 5 were inferred between 7550-4600, 2750-1300 and -50 cal. yr BP, by the dominance of Nebela militaris, Difflugia pulex and Phryganella acropodia. These overall dry conditions were also connected with increased abundance of Eriophorum vaginatum. The period between 400 and -50 cal. yr BP was characterized by a rapid shift from dry to wet conditions on the surface of the bog. Vegetation shifted from Sphagnum magellanicum to Sphagnum russowii dominated community. Our reconstruction remains in relatively good agreement with other palaeohydrological records from Central Eastern Europe. However, it shows contrasting conditions to others particularly with records from NW Europe. The valuable information regarding bog hydrology offered by our record puts an accent on the need of more regional TA based reconstruction studies, to get a compressive picture of larger spatial scales of hydro-climate variability in Europe.

Landscape analysis of nutrient-enriched margins (lagg) in ombrotrophic peatlands.

PubMed

Langlois, Mélanie N; Price, Jonathan S; Rochefort, Line

2015-02-01

Scientific knowledge of the wet zone - the lagg - that tends to form at the edge of ombrotrophic peatlands is surprisingly limited. In this study, we aim to improve the understanding of the ecohydrological functions of this transition by describing the form and abiotic controls of the laggs and margins of bog peatlands. Data collected in wells and piezometers along 10 transects (within 6 bogs), of the New Brunswick Eastern Lowlands are used to analyse the hydraulic and hydrochemical gradients, while airborne LiDAR data provides new insight on the geomorphology and the vegetation patterns of the bog-lagg-mineral transition zone. Based on their geomorphic character, the study transects are placed into 2 categories: confined and unconfined. Laggs of confined transition are found in a topographic depression, between the bog and a mineral slope >1%, while laggs of unconfined transitions are adjacent to a flat (≤1%) or receding mineral slope (sloping away from the lagg). Water level (4 ± 9 cm vs. -3 ± 9 cm), pH (4.8 ± 0.9 vs. 4.2 ± 0.4), electrical conductivity (ECcorr) (105 ± 52 μS cm(-1) vs. 52 ± 28 μS cm(-1)) and peat depth (55 ± 9 cm vs. 30 ± 9 cm) are found to be higher, respectively, for the confined laggs than for the unconfined. Saturated hydraulic conductivity (Ksat) of the lagg's upper peat layer resembles that of bog environments, but quickly reduces with depth, impeding vertical water flow. The greatest abiotic control of the lagg appears to be topography, which affects water flow rates and direction, thus water chemistry, nutrient transport and availability, hence vegetation characteristics. Our results suggest that the features of the transition zone that include the lagg, influence the quantity and variability of water within the adjacent peatland, and should be considered as integral part of the peatland complex. Copyright © 2014 Elsevier B.V. All rights reserved.

Characterizing dissolved organic carbon concentrations and export in a boreal forest-peatland landscape under the influence of rapidly degrading discontinuous permafrost

NASA Astrophysics Data System (ADS)

Hanisch, J.; Connon, R.; Templeton, M.; Quinton, W. L.; Olefeldt, D.; Moore, T. R.; Roulet, N. T.; Sonnentag, O.

2014-12-01

Our current understanding of peatland energy, water and carbon (C) cycles implies that northern peatlands are vulnerable to projected climate change, and that the perturbation of these cycles might cause a strong positive or negative net feedback to the climate system. About one third of Canada's northern peatlands contain contain perennialy frozen ground (permafrost). Boreal forest-peatland ecosystems in the discontinuous permafrost zone (50-90% of frozen ground) are especially vulnerable to rising temperatures as permafrost is ice-rich, relatively warm and thin, and thus susceptible to complete disappearance causing ground surface subsidence and a decline in forest cover in response to water-logging. Several recent studies have substantially improved our understanding of northern peatland's role in the climate system by quantifying their net ecosystem C balance which includes atmospheric and aqueous C fluxes generally dominated by the export of dissolved organic C (DOC). We characterize seasonal and diurnal variations in DOC export from five catchments (0.02-0.05 km2) at Scotty Creek, a 152 km2-watershed under the influence of rapidly degrading and disappearing discontinuous permafrost near Fort Simpson, Northwest Territories, Canada. The five catchments are characterized by different fractions of forested peat plateaus with permafrost (38-73%) and permafrost-free collapse bogs (27-62%). Dissolved organic carbon concentrations at Scotty Creek appear to be higher in catchments where the percentage of peat plateaus is higher compared to bogs, independent of catchment size. Average DOC concentration for catchments with a lower percentage of peat plateaus is lower (~43 mg/l) than for those with a higher percentage of plateaus (~60 mg/l). These preliminary results suggest that lateral C losses from this rapidly changing landscape are at least partly controlled by the peat plateau-bog ratio. Over the year, DOC export from the five catchments is limited to around a week due to the relatively dry conditions at Scotty Creek over the hot summer months: only one of the catchments produces continuous measurable surface runoff. However, as indicated through water level recordings, additional unaccounted DOC export may occur through diffuse subsurface flow.

The Late Quaternary peat, vegetation and climate history of the Southern Oceanic Islands of New Zealand

NASA Astrophysics Data System (ADS)

McGlone, M. S.

2002-02-01

Seven oceanic island groups (Chatham, Bounty, Snares, Antipodes, Auckland, Campbell and Macquarie) lie to the south and east of the southern New Zealand mainland between the Subtropical Convergence and the Antarctic Convergence. They are highly oceanic, experiencing moist, cool, cloudy and windy climates. Deep peat soils cover most of the islands, except for steep slopes and exposed high altitude sites. The three large island groups (Chatham, Auckland and Campbell) support forest and tall scrub in the lowlands, in the latter two grading with altitude through shrubland and grassland to upland tundra. Macrophyllous forbs create luxuriant herbfields in nutrient-rich coastal sites and also, as stunted forms, dominate upland tundra associations. The southernmost island, Macquarie has no woody species, and is covered with tussock grassland, herbfield and tundra. Vegetation cover is highly sensitive to soil saturation and exposure to the strong westerly winds of this region. Extensive oligotrophic bogs occur where drainage is poor and exposure high, and forest and tall scrub are abundant only in sheltered, well-drained lowland sites. Glacial cirque levels indicate mean annual temperatures fell by 5-6°C during the Last Glacial Maximum. A depression of 6-10°C in sea surface temperatures is suggested by deep-sea core analyses, but this seems incompatible with terrestrial evidence. Auckland and Campbell Islands were extensively glaciated, and grassland, herbfield and tundra landscapes prevailed. Glaciers retreated by 15,000 yr BP, and landscapes had stabilised and peat soils begun forming by 12,000 yr BP. By the beginning of the Holocene, oligotrophic bog, grassland and shrubland were dominant. Scrub and low forest spread slowly during the early Holocene in the Chatham, Auckland and Campbell Islands, inhibited by cloudy, moist climates, low insolation and wet soils. Maximum extent of forest and scrub occurred between 6000 and 2000 yr BP, most probably linked with a drying of the soils and increasing summer insolation. Upland sites and those exposed to westerly gales on Auckland and Campbell Islands remained in grassland, herbfield and bog throughout the Holocene. Wind-blown sand and stones in cliff edge peat profiles on Auckland and Campbell Island from 8000 yr BP suggest strengthening westerly winds.

Carbon budget of oligotrophic mires in the Southern Taiga of Western Siberia under anthropogenic impact

NASA Astrophysics Data System (ADS)

Golovatskaya, Eugenia; Dyukarev, Egor

2010-05-01

Role of peatlands in the global greenhouse gases budget is highly relevant. According to present estimates peatlands in undisturbed conditions act as a sink for the atmospheric carbon. Anthropogenic impact on peatlands (melioration, changes in land use, influence of underground water catchments) results in water table lowering, changing in vegetation cover, and degradation of peat deposit. Peatlands could provide a significant positive feedback for climate changes if warming and peatlands drying stimulates bulk soil organic matter decomposition which enhances CO2 release to the atmosphere. Western Siberian peatlands usually represented big bog massifs. Big peatlands have higher stability to external influence. Small peatlands have all signs of big bogs but react on changes in environmental variables more quickly. The present study is devoted to investigation of primary carbon fluxes (CO2 emission and net primary productivity) and carbon balance at oligotrophic bogs in native condition (key area "Bakchar") and under anthropogenic impact (key area "Ob'-Tom'"). The key area "Bakchar" is located between the Iksa and Bakchar rivers (56o58`N 82o36`E) at the Bakcharskoe bog (area 1400 km2). The key area "Ob'-Tom'"is located in the northern part of Ob' and Tom' interfluve (56o21`N 82o31`E). The "Bakchar" key area includes the following ecosystems: pine- shrub-sphagnum community, a similar community with stunted (low) pine trees, and sedge-sphagnum fen. Two small peatlands were studied at Ob' and Tom' interfluve. Kirsanovskoe bog includes pine- shrub-sphagnum community and sedge fen. Timiryazevskoe bog was represented by pine- shrub-sphagnum (TPSS) community and sedge fen. An infrared gas analyzer OPTOGAS 500.4 (OPTEC Corp., St.-Petersburg, Russia) attached to a static opaque plastic been used for carbon dioxide emission measurements. The net primary productivity was measured by clipping method (Golovatskaya and Dyukarev, Plant Soil 2009). Peatlands at "Ob'-Tom'" key area are under impact of water catchments for Tomsk city supply. Changes in deep waters results in changes of hydrological regime and environment transformations. Water level drawdown leads to increase of aerobic layer thickness, intensification of plant remains decomposition, peat layers compacting and rises of CO2 emission from the surface. Carbon dioxide emission from bogs of "Ob'-Tom'" key area is about two times higher than emission from pristine bogs ("Bakchar" key area). Aboveground net primary productivity determined without tree layer at all studied peatlands has similar values. Belowground net primary productivity at "Ob'-Tom'" key area if 4-7 times higher than at "Bakchar" key area depending on the ecosystem type. An essential increase in root density after water level depletion results in increase on total net productivity by 2.4 times. Carbon budget for pristine peatlands ("Bakchar" key area) varies from 27 (open fen) to 46 (low ryam) gC/m2/yr. Peatlands of "Ob'-Tom'" key area accumulates about 210 gC/m2/yr in average. Our observations of the elements of carbon exchange have shown that at present all studied peatlands act as carbon sinks. Long-term water table lowering at least at first stage stipulates carbon removing from the atmosphere and accumulation in a form of peat. Work was partially supported by Russian Fund of Basic Researches (08-05-00426/a, 08-05-92501).

Peat bogs as hotspots for organoarsenical formation and persistence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mikutta, Christian; Rothwell, James J.

Here, peatlands have received significant atmospheric inputs of As and S since the onset of the Industrial Revolution, but the effect of S deposition on the fate of As is largely unknown. It may encompass the formation of As sulfides and organosulfur-bound As, or the indirect stimulation of As biotransformation processes, which are presently not considered as important As immobilization pathways in wetlands. To investigate the immobilization mechanisms of anthropogenically derived As in peatlands subjected to long-term atmospheric pollution, we explored the solid-phase speciation of As, Fe, and S in English peat bogs by X-ray absorption spectroscopy. Additionally, we analyzedmore » the speciation of As in pore- and streamwaters. Linear combination fits of extended X-ray absorption fine structure (EXAFS) data imply that 62–100% (average: 82%) of solid-phase As (As tot: 9–92 mg/kg) was present as organic As(V) and As(III). In agreement with appreciable concentrations of organoarsenicals in surface waters (pH: 4.0–4.4, Eh: 165–190 mV, average Astot: 1.5–129 μg/L), our findings reveal extensive biotransformation of atmospheric As and the enrichment of organoarsenicals in the peat, suggesting that the importance of organometal(loid)s in wetlands subjected to prolonged air pollution is higher than previously assumed.« less

Peat bogs as hotspots for organoarsenical formation and persistence

DOE PAGES

Mikutta, Christian; Rothwell, James J.

2016-04-01

Here, peatlands have received significant atmospheric inputs of As and S since the onset of the Industrial Revolution, but the effect of S deposition on the fate of As is largely unknown. It may encompass the formation of As sulfides and organosulfur-bound As, or the indirect stimulation of As biotransformation processes, which are presently not considered as important As immobilization pathways in wetlands. To investigate the immobilization mechanisms of anthropogenically derived As in peatlands subjected to long-term atmospheric pollution, we explored the solid-phase speciation of As, Fe, and S in English peat bogs by X-ray absorption spectroscopy. Additionally, we analyzedmore » the speciation of As in pore- and streamwaters. Linear combination fits of extended X-ray absorption fine structure (EXAFS) data imply that 62–100% (average: 82%) of solid-phase As (As tot: 9–92 mg/kg) was present as organic As(V) and As(III). In agreement with appreciable concentrations of organoarsenicals in surface waters (pH: 4.0–4.4, Eh: 165–190 mV, average Astot: 1.5–129 μg/L), our findings reveal extensive biotransformation of atmospheric As and the enrichment of organoarsenicals in the peat, suggesting that the importance of organometal(loid)s in wetlands subjected to prolonged air pollution is higher than previously assumed.« less

A reconstruction of vegetation and paleohydrologycal changes from peatland in Kansk forest-steppe, Yenisei Siberia

NASA Astrophysics Data System (ADS)

Rodionova, Alexandra

2016-04-01

Peatlands are an important natural archive for past climatic changes. Climatic changes throughout the Holocene have been reconstructed from peat using a wide array of biological and other proxies. Many different proxy indicators can be derived from peat cores allowing for a multi-proxy approach to climatic reconstructions. Peat-based climatic and environmental reconstructions are currently available from many sites in Yenisei Siberia, mainly for its northern territories. The purpose of this paper is to study some features of peatland development and environmental reconstructions from the Holocene period in the south part of Yenisei Siberia (Kansk forest-steppe zone). The main method used in this research is macrofossil analysis. It can be used to reconstruct the development of local vegetation and surface wetness on peatlands. The macrofossil analysis in the peat resulted from the study of the vegetation in a particular place over a period of time, and it allowed the reconstruction of environmental changes that have occurred since the Late Glacial. Then we used ecological scales of moisture and reconstructed surface wetness for the entire period of the bog formation. Radiocarbon dating was carried out at Sobolev Institute of Geology and Mineralogy, Russian Academy of Sciences, Novosibirsk . Peatland "Pinchinskoye" was selected for investigation in Kansk forest-steppe. It is located on the right bank of the Yenisei River in the floodplain of Esaulovka River. Peat cores of 350 cm were selected in the southern part of the peatbog, including 225 cm of peat (with loam layers in the range of 90 to 135 cm), 75 cm of organic and mineral sapropel with the inclusion of fossil shells of mollusks and different plant macrofossils and 50 cm of the loam below. The process of peat accumulation dated back 8400 ± 140 years, which is the oldest date for the forest-steppe zone of Yenisei Siberia. The climate of Boreal period of the Holocene was chilly. Under these conditions, in the territory of the peatland "Pinchinskoye" there was a small lake. The birch forest with different grasses was growing along the banks of the lake. The lake level dropped significantly at the beginning of the Atlantic period around 7000 BP in a warm and dry climate. This launched the lake overgrowth and eutrophication. Birch forests and then spruce forests rich in herbs with green moss emerged in the peatland. An increase in moisture was recorded for the Sub-Boreal period (4900-2400) and, as a result, the prevalence of marsh communities with bog bean and fern. Increasing water level of rovers led to the spill and silting up of the bog surface in 2020 ± 60 BP at the beginning of the Sub-Atlantic period. After the decline of the water level, the process of peat accumulation continued and spread out throughout the whole trough flat. Sedge, cotton grass, sphagnum moss and green moss predominated in the composition of plant communities in Sub-Atlantic period, starting from 1500 BP. In the last 500 years, the peatland moved to the mesoeutrophic phase of development.

Nitrogen and Phosphorus Addition Affects Biological N2 Fixation and Sphagnum Moss in an Ombrotrophic Bog

NASA Astrophysics Data System (ADS)

Zivkovic, T.; Ardichvili, A.; Moore, T. R.

2016-12-01

Most of the 18 Pg nitrogen (N) accumulated in northern nutrient-poor and Sphagnum-dominated peatlands (bogs and fens) can be attributed to N2 fixation by diazotrophs either associated with the live Sphagnum or non-symbiotically in the deeper peat. Where atmospheric N deposition is low (< 0.2 g m-2 y-1), ombrotrophic bogs rely on N2 fixation as the primary source of N that sustains primary production. The industrial revolution and anthropogenic impacts in the last 200 years have resulted in larger atmospheric N deposition as ammonium (NH4) and nitrate (NO3). One effect of increased N deposition in Sphagnum is a switch from N to phosphorus (P) limitation suggested by the increase in tissue N:P>16. It is unclear how Sphagnum hosted diazotrophic activity may be affected by N deposition and thus changes in N:P ratio. We investigated the effects of long-term addition of different sources of nitrogen (0, 1.6, 3.2 and 6.4 g N m-2 y-1 as NH4Cl and NaNO3), and phosphorus (5 g P m-2 y-1 as KH2PO4) on Sphagnum nutrient status (N, P and N:P), net primary productivity (NPP) and Sphagnum-associated N2 fixation at Mer Bleue, a temperate ombrotrophic bog. Our study shows that N concentration in Sphagnum tissue increased with larger rates of N addition, with a stronger effect on Sphagnum from NH4 than NO3. The addition of P created a 3.5 fold increase in Sphagnum P content compared to controls. Sphagnum NPP decreased linearly with the rise in N:P ratio, while linear growth declined exponentially with increase in Sphagnum N content. N2 fixation significantly decreased in response to even the smallest addition of both N species. In contrast, the addition of P increased N2 fixation by up to 100 times compared to N treatments and up to 5-30 times compared to controls. The change in N2 fixation was best modeled by the N:P ratio, across all experimental treatments. Although elevated N deposition substantially decreases N2 fixation, the N:P ratio in Sphagnum may be a good predictor, likely owing to a strong P-limitation.

Controls on northern wetland methane emissions: insights from regional synthesis studies and the Alaska Peatland Experiment (APEX)

NASA Astrophysics Data System (ADS)

Turetsky, M. R.; Euskirchen, E. S.; Czimczik, C. I.; Waldrop, M. P.; Olefeldt, D.; Fan, Z.; Kane, E. S.; McGuire, A. D.; Harden, J. W.

2014-12-01

Wetlands are the largest natural source of atmospheric methane. Static chambers have been used to quantify variation in wetland CH4 flux for many decades. Regional to global scale synthesis studies of static chamber measurements show that relationships between temperature, water availability and CH4 emissions depend on wetland type (bog, fen, swamp), region (tropical, temperate, arctic) and disturbance. For example, while water table position and temperature serve as the dominant controls on bog and swamp CH4 flux, vegetation is an important control on emissions from fens. These studies highlight the fact that wetland types have distinct controls on CH4 emissions; however, it is unlikely that modeling of wetland CH4 flux will improve without a better mechanistic understanding of the processes underlying CH4 production, transport, and oxidation. At the Alaska Peatland Experiment, we are quantifying CH4 emission using static chambers, automated chambers, and towers. Our sites vary in permafrost regime, including groundwater fens without permafrost, forested peat plateaus with intact permafrost, and collapse scar bogs formed through permafrost thaw. Experimental studies that examine plant and microbial responses to altered water table position and soil temperature are complemented by a gradient approach, where we use a space-for-time substitutions to examine the consequences of thaw on time-scales of decades to centuries. Our results thus far have documented the importance of soil rewetting in governing large CH4 fluxes from northern wetland soils. Accounting for CH4, our collapse scar bog significantly contributed to the global warming potential of the landscape. A major objective of our work is to explore the role of permafrost C release in greenhouse gas fluxes from wetland soils, which we are assessing using radiocarbon as a natural tracer. We have shown, for example, that ebullition of CH4 is dominated by recently fixed C, but a significant fraction of CH4 in bubbles is derived from old C released during thaw. The APEX time series datasets are being used in a variety of modeling studies, from small-scale soil pore and microbial controls on gas production and transport to regional scale assessments of how carbon cycle feedbacks to climate vary with wetland type and abundance.

SPRUCE S1 Bog Sphagnum CO2 Flux Measurements and Partitioning into Re and GPP

DOE Data Explorer

Walker, A. P. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Carter, K. R. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hanson, P. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Nettles, W. R. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Philips, J. R. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Sebestyen, S. D. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Weston, D. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.

2015-06-01

This data set provides (1) the results of in-situ Sphagnum-peat hourly net ecosystem exchange (NEE) measured using a LICOR 8100 gas exchange system and (2) the component fluxes -- gross primary production (GPP) and ecosystem respiration (Re), derived using empirical regressions.NEE measurements were made from 6 June to 6 November 2014 and 20 March to 10 May 2015. Three 8100 chambers per dominant species (S. magellanicum or S. fallax) were placed in the S1 Bog in relatively open ground where there was no obvious hummock-hollow microtopography. The 8100 chambers were not located in the SPRUCE experimental enclosures.

Renewable Energy Capability vs. Climate Necessity

ERIC Educational Resources Information Center

Mills, David

2006-01-01

A 450-ppm equivalent CO[2] target by 2050 is an often-proposed goal under a future global emissions agreement, but there is considerable high side risk in global-warming models due to cloud formation, feedbacks in dissolved organic carbon from peat bogs in polar regions, and unaccounted solar dimming by particulates. The 450-ppm figure is…

Deep peat warming increases surface methane and carbon dioxide emissions in a black spruce-dominated ombrotrophic bog.

PubMed

Gill, Allison L; Giasson, Marc-André; Yu, Rieka; Finzi, Adrien C

2017-12-01

Boreal peatlands contain approximately 500 Pg carbon (C) in the soil, emit globally significant quantities of methane (CH 4 ), and are highly sensitive to climate change. Warming associated with global climate change is likely to increase the rate of the temperature-sensitive processes that decompose stored organic carbon and release carbon dioxide (CO 2 ) and CH 4 . Variation in the temperature sensitivity of CO 2 and CH 4 production and increased peat aerobicity due to enhanced growing-season evapotranspiration may alter the nature of peatland trace gas emission. As CH 4 is a powerful greenhouse gas with 34 times the warming potential of CO 2 , it is critical to understand how factors associated with global change will influence surface CO 2 and CH 4 fluxes. Here, we leverage the Spruce and Peatland Responses Under Changing Environments (SPRUCE) climate change manipulation experiment to understand the impact of a 0-9°C gradient in deep belowground warming ("Deep Peat Heat", DPH) on peat surface CO 2 and CH 4 fluxes. We find that DPH treatments increased both CO 2 and CH 4 emission. Methane production was more sensitive to warming than CO 2 production, decreasing the C-CO 2 :C-CH 4 of the respired carbon. Methane production is dominated by hydrogenotrophic methanogenesis but deep peat warming increased the δ 13 C of CH 4 suggesting an increasing contribution of acetoclastic methanogenesis to total CH 4 production with warming. Although the total quantity of C emitted from the SPRUCE Bog as CH 4 is <2%, CH 4 represents >50% of seasonal C emissions in the highest-warming treatments when adjusted for CO 2 equivalents on a 100-year timescale. These results suggest that warming in boreal regions may increase CH 4 emissions from peatlands and result in a positive feedback to ongoing warming. © 2017 John Wiley & Sons Ltd.

High diversity of tropical peatland ecosystem types in the Pastaza-Marañón basin, Peruvian Amazonia

NASA Astrophysics Data System (ADS)

LäHteenoja, Outi; Page, Susan

2011-06-01

Very little information exists on Amazonian peatlands with most studies on tropical peatlands concentrating on Southeast Asia. Here we describe diversity of Amazonian peatland ecosystems and consider its implications for the global diversity of tropical peatland ecosystems. Nine study sites were selected from within the most extensive wetland area of Peruvian Amazonia: the 120,000 km2 Pastaza-Marañón basin. Peat thickness was determined every 500 m from the edge toward the center of each site, and peat samples were collected from two cores per site. Samples from the entire central core and surface samples from the other core were analyzed for nutrient content. Topography of four peat deposits was measured. In order to study differences in vegetation, pixel values were extracted from a satellite image. The surface peat nutrient content of the peatlands varied from very nutrient-rich to nutrient-poor. Two of the peatlands measured for their topography were domed (5.4 and 5.8 m above the stream), one was gently sloping (1.4 m above the stream), and one was flat and occurred behind a 7 m high levee. Five different peatland vegetation types were detected on the basis of pixel values derived from the satellite image. The peat cores had considerable variation in nutrient content and showed different developmental pathways. In summary, the Pastaza-Marañón basin harbors a considerable diversity of previously undescribed peatland ecosystems, representing a gradient from atmosphere-influenced, nutrient-poor ombrotrophic bogs through to river-influenced, nutrient-rich swamps. Their existence affects the habitat diversity, carbon dynamics, and hydrology of the Amazonian lowlands, and they also provide an undisturbed analog for the heavily disturbed peatlands of Southeast Asia. Considering the factors threatening the Amazonian lowlands, there is an urgent need to investigate and conserve these peatland ecosystems, which may in the near future be among the very few undisturbed tropical ombrotrophic bogs remaining in the world.

Biochemical processes of oligotrophic peat deposits of Vasyugan Mire

NASA Astrophysics Data System (ADS)

Inisheva, L. I.; Sergeeva, M. A.

2009-04-01

The problem of peat and mire ecosystems functioning and their rational use is the main problem of biosphere study. This problem also refers to forecasting of biosphere changes results which are global and anthropogenic. According to many scientists' research the portion of mires in earth carbon balance is about 15% of world's stock. The aim of this study is to investigate biochemical processes in oligotrophic deposits in North-eastern part of Vasyugan Mire. The investigations were made on the territory of scientific-research ground (56˚ 03´ and 56˚ 57´ NL, 82˚ 22´ and 82˚ 42´ EL). It is situated between two rivers Bakchar and Iksa (in outskirts of the village Polynyanka, Bakchar region, Tomsk oblast). Evolution of investigated mire massif began with the domination of eutrophic phytocenosis - Filicinae, then sedge. Later transfer into oligotrophic phase was accompanied by formation of meter high-moor peat deposit. The age of three-meter peat deposit reaches four thousand years. Biochemical processes of carbon cycle cover the whole peat deposit, but the process activity and its direction in different layers are defined by genesis and duration of peat formation. So, the number of cellulose-fermenting aerobes in researched peat deposits ranges from 16.8 to 75.5 million CFU/g, and anaerobic bacteria from 9.6 to 48.6 million CFU/g. The high number of aerobes is characteristic for high water levels, organizing by raised bog peats. Their number decreases along the profile in 1.7 - 2 times. The number of microflora in peat deposit is defined by the position in the landscape profile (different geneses), by the depth, by hydrothermic conditions of years and individual months. But microflora activity shows along all depth of peat deposit. We found the same in the process of studying of micromycete complex structure. There was revealed either active component micromycete complex - mycelium, or inert one - spores in a meter layer of peat deposit. If mushrooms spores are observed in all deposit layers, mycelium of mushrooms deepens into the peat deposit (to 2 meters) within the limits of aerobic (meter) zone and only in particular months of dry years. The existence of seasonal dynamics of eukaryotic cells, and also capability of yeast and other groups of micromycetes for growth, testifies about vital activity of a number of eukaryotic cells at a depth of 2 meters. Researched peat deposits are biochemically active along the whole profile. But they are different in a microflora number of individual physiological groups either in items of the landscape, or in deposit depth. The largest quantity of aerobic cellulose-fermenting microorganisms is marked during dry years. Anaerobic cellulose-fermenting microorganisms dominate during wet years. The quantity of microbe biomass increases in bottom lifts of peat deposits. This fact testifies about viable condition of microbe complex at depth. The formation process of carbon dioxide in peat deposits of Vasyugan Mire actively occurs during dry years and is defined by hydrothermic conditions of a meter layer of peat deposit. The intensity of CO2 isolation for certain correlates with the temperature in horizon of 0 - 50 sm. and with bog waters level. The study of gas composition for the three years showed that the largest concentration of carbon dioxide in peat soils is marked along the whole profile during a dryer year (0.08 - 2.65 millimole/l), increasing other years' level in about 1.5 0 2 times. Emission of carbon dioxide in peat

Evaporation from a sphagnum moss surface

Treesearch

D.S. Nichols; J.M. Brown

1980-01-01

Peat cores, 45 cm in diameter, were collected from a sphagnum bog in northern Minnesota, and used to measure the effects of different temperatures and water levels on evaporation from a sphagnum moss surface in a growth chamber. Under all conditions, evaporation from the moss surface was greater than that from a free-water surface. Evaporation from the moss increased...

Temperature sensitivity differences with depth and season between carbon, nitrogen, and phosphorus cycling enzyme activities in an ombrotrophic peatland system

NASA Astrophysics Data System (ADS)

Steinweg, J. M.; Kostka, J. E.; Hanson, P. J.; Schadt, C. W.

2017-12-01

Northern peatlands have large amounts of soil organic matter due to reduced decomposition. Breakdown of organic matter is initially mediated by extracellular enzymes, the activity of which may be controlled by temperature, moisture, and substrate availability, all of which vary seasonally throughout the year and with depth. In typical soils the majority of the microbial biomass and decomposition occurs within the top 30cm due to reduced organic matter inputs in the subsurface however peatlands by their very nature contain large amounts of organic matter throughout their depth profile. We hypothesized that potential enzyme activity would be greatest at the surface of the peat due to a larger microbial biomass compared to 40cm and 175cm below the surface and that temperature sensitivity would be greatest at the surface during winter but lowest during the summer due to high temperatures and enzyme efficiency. Peat samples were collected in February, July, and August 2012 from the DOE Spruce and Peatland Responses Under Climatic and Environmental Change project at Marcell Experimental Forest S1 bog. We measured potential activity of hydrolytic enzymes involved in three different nutrient cycles: beta-glucosidase (carbon), leucine amino peptidase (nitrogen), and phosphatase (phosphorus) at 15 temperature points ranging from 3°C to 65°C. Enzyme activity decreased with depth as expected but there was no concurrent change in activation energy (Ea). The reduction in enzyme activity with depth indicates a smaller pool which coincided with a decreased microbial biomass. Differences in enzyme activity with depth also mirrored the changes in peat composition from the acrotelm to the catotelm. Season did play a role in temperature sensitivity with Ea of β-glucosidase and phosphatase being the lowest in August as expected but leucine amino peptidase (a nitrogen acquiring enzyme) Ea was not influenced by season. As temperatures rise, especially in winter months, enzymatic carbon and phosphorus acquisition in the Marcell bog may increase whereas nitrogen acquisition would remain unchanged. The lack of temperature response for leucine amino peptidase has been measured in other systems but may be less of a concern in the Marcell bog due to low microbial biomass and enzymatic activity at depth and relatively low peat C:N ratios.

Rain increases methane production and methane oxidation in a boreal thermokarst bog

NASA Astrophysics Data System (ADS)

Neumann, R. B.; Moorberg, C.; Turner, J.; Wong, A.; Waldrop, M. P.; Euskirchen, E. S.; Edgar, C.; Turetsky, M. R.

2017-12-01

Bottom-up biogeochemical models of wetland methane emissions simulate the response of methane production, oxidation and transport to wetland conditions and environmental forcings. One reason for mismatches between bottom-up and top-down estimates of emissions is incomplete knowledge of factors and processes that control microbial rates and methane transport. To advance mechanistic understanding of wetland methane emissions, we conducted a multi-year field investigation and plant manipulation experiment in a thermokarst bog located near Fairbanks, Alaska. The edge of the bog is experiencing active permafrost thaw, while the center of the bog thawed 50 to 100 years ago. Our study, which captured both an average year and two of the wettest years on record, revealed how rain interacts with vascular vegetation and recently thawed permafrost to affect methane emissions. In the floating bog, rain water warmed and oxygenated the subsurface, but did not alter soil saturation. The warmer peat temperatures increased both microbial methane production and plant productivity at the edge of the bog near the actively thawing margin, but minimally altered microbial and plant activity in the center of the bog. These responses indicate processes at the edge of the bog were temperature limited while those in the center were not. The compounding effect of increased microbial activity and plant productivity at the edge of the bog doubled methane emissions from treatments with vascular vegetation during rainy years. In contrast, methane emissions from vegetated treatments in the center of the bog did not change with rain. The oxygenating influence of rain facilitated greater methane oxidation in treatments without vascular vegetation, which offset warming-induced increases in methane production at the edge of the bog and decreased methane emissions in the center of the bog. These results elucidate the complex and spatially variable response of methane production and oxidation in thermokarst bogs to energy and oxygen inputs from rain, and have implications for how boreal wetland methane emissions may respond in the future to altered precipitation patterns. Advective delivery of energy and oxygen to wetland subsoils via rainwater is not currently a mechanism included in bottom-up wetland methane models.

CO2 and CH4 fluxes of contrasting pristine bogs in southern Patagonia (Tierra del Fuego, Argentina)

NASA Astrophysics Data System (ADS)

Münchberger, Wiebke; Blodau, Christian; Kleinebecker, Till; Pancotto, Veronica

2015-04-01

South Patagonian peatlands cover a wide range of the southern terrestrial area and thus are an important component of the terrestrial global carbon cycle. These extremely southern ecosystems have been accumulating organic material since the last glaciation up to now and are - in contrast to northern hemisphere bogs - virtually unaffected by human activities. So far, little attention has been given to these pristine ecosystems and great carbon reservoirs which will potentially be affected by climate change. We aim to fill the knowledge gap in the quantity of carbon released from these bogs and in what controls their fluxes. We study the temporal and spatial variability of carbon fluxes in two contrasting bog ecosystems in southern Patagonia, Tierra del Fuego. Sphagnum-dominated bog ecosystems in Tierra del Fuego are similar to the ones on the northern hemisphere, while cushion plant-dominated bogs can almost exclusively be found in southern Patagonia. These unique cushion plant-dominated bogs are found close to the coast and their occurrence changes gradually to Sphagnum-dominated bogs with increasing distance from the coast. We conduct closed chamber measurements and record relevant environmental variables for CO2 and CH4 fluxes during two austral vegetation periods from December to April. Chamber measurements are performed on microforms representing the main vegetation units of the studied bogs. Gas concentrations are measured with a fast analyzer (Los Gatos Ultraportable Greenhouse Gas Analyzer) allowing to accurately record CH4 fluxes in the ppm range. We present preliminary results of the carbon flux variability from south Patagonian peat bogs and give insights into their environmental controls. Carbon fluxes of these two bog types appear to be highly different. In contrast to Sphagnum-dominated bogs, cushion plant-dominated bogs release almost no CH4 while their CO2 flux in both, photosynthesis and respiration, can be twice as high as for Sphagnum-dominated bogs. Water table fluctuations in the cushion plant-dominated bog seem to be negligible and CH4 is mainly released from Sphagnum lawns suggesting the importance of the vegetation type for CH4 fluxes in these special ecosystems. Our results will help to understand which conditions favor the development of either a cushion plant-dominated or Sphagnum-dominated bog which is not yet known.

Polygonal patterned peatlands of the White Sea islands

NASA Astrophysics Data System (ADS)

Kutenkov, S. A.; Kozhin, M. N.; Golovina, E. O.; Kopeina, E. I.; Stoikina, N. V.

2018-03-01

The summits and slopes of some islands along the northeastern and northern coasts of the White Sea are covered with dried out peatlands. The thickness of the peat deposit is 30–80 cm and it is separated by troughs into gently sloping polygonal peat blocks up to 20 m2 in size. On some northern islands the peat blocks have permafrost cores. The main components of the dried out peatlands vegetation are dwarf shrubs and lichens. The peat stratigraphy reveals two stages of peatland development. On the first stage, the islands were covered with wet cottongrass carpets, which repeated the convex relief shape. On the second stage, they were occupied by the xeromorphic vegetation. We suggest that these polygonal patterned peatlands are the remnants of blanket bogs, the formation of which assumes the conditions of a much more humid climate in the historical past. The time of their active development was calculated according to the White Sea level changes and radiocarbon dates from 1000–4000 BP.

Tropical organic soils ecosystems in relation to regional water resources in southeast Asia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armentano, T. V.

1982-01-01

Tropical organic soils have functioned as natural sinks for carbon, nitrogen, slfur and other nutrients for the past 4000 years or more. Topographic evolution in peat swamp forests towards greater oligotrophy has concentrated storage of the limited nutrient stock in surface soils and biota. Tropical peat systems thus share common ecosystem characteristics with northern peat bogs and certain tropical oligotrophic forests. Organic matter accumulation and high cation-exchange-capacity limit nutrient exports from undisturbed organic soils, although nutrient retention declines with increasing eutrophy and wetland productivity. Peat swamps are subject to irreversible degradation if severely altered because disturbance of vegetation, surface peatsmore » and detritus can disrupt nuttrient cycles and reduce forest recovery capacity. Drainage also greatly increases exports of nitrogen, phosphorus and other nutrients and leads to downstream eutrophication and water quality degradation. Regional planning for clean water supplies must recognize the benefits provided by natural peatlands in balancing water supplies and regulating water chemistry.« less

Environmental factors controlling methane emissions from peatlands in northern Minnesota

NASA Technical Reports Server (NTRS)

Dise, Nancy B.; Gorham, Eville; Verry, Elon S.

1993-01-01

The environmental factors affecting the emission of methane from peatlands were investigated by correlating CH4 emission data for two years, obtained from five different peatland ecosystems in northern Minnesota, with peat temperature, water table position, and degree of peat humification. The relationship obtained between the CH4 flux and these factors was compared to results from a field manipulation experiment in which the water table was artificially raised in three experimental plots within the driest peatland. It was found that peat temperature, water table position, and degree of peat humification explained 91 percent of the variance in log CH4 flux, successfully predicted annual CH4 emission from individual wetlands, and predicted the change in flux due to the water table manipulation. Raising the water table in the bog corrals by an average of 6 cm in autumn 1989 and 10 cm in summer 1990 increased CH4 emission by 2.5 and 2.2 times, respectively.

Relevance of peat-draining rivers for the riverine input of dissolved iron into the ocean.

PubMed

Krachler, Regina; Krachler, Rudolf F; von der Kammer, Frank; Süphandag, Altan; Jirsa, Franz; Ayromlou, Shahram; Hofmann, Thilo; Keppler, Bernhard K

2010-05-01

Peat bogs have the ability to produce strong chelate ligands (humic and fulvic acids) which enhance the weathering rates of iron-silicate minerals and greatly increase the solubility of the essential trace metal iron in river water. Fluvial networks link peat bogs with the ocean, and thus terrestrial-derived fulvic-iron complexes fuel the ocean's biological productivity and biological carbon pump, but understanding this role is constrained by inconsistent observations regarding the behaviour of riverine iron in the estuarine mixing zone, where precipitation reactions remove iron from the water column. We applied a characterization of the colloidal iron carriers in peatland-draining rivers in North Scotland, using field-flow fractionation (FFF), in combination with end-member mixing experiments of river water sampled near the river mouth and coastal seawater using a (59)Fe radiotracer method. According to our results, the investigated river contributed "truly dissolved" Fe concentrations of about 3300nmolL(-1) to the ocean which is nearly two orders of magnitude higher than the dissolved iron contribution of the "average world" river ( approximately 40nmolL(-1)). Thus we conclude that peatland-draining rivers are important sources of dissolved iron to the ocean margins. We propose highly electrostatic and sterical stabilized iron-organic matter complexes in the size range of <2kDa to be responsible for iron transport across the estuarine mixing zone. Copyright 2010 Elsevier B.V. All rights reserved.

Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands

USGS Publications Warehouse

Jones, Miriam C.; Harden, Jennifer W.; O'Donnell, Jonathan A.; Manies, Kristen L.; Jorgenson, Torre; Treat, Claire C.; Ewing, Stephanie

2017-01-01

Permafrost peatlands store one-third of the total carbon (C) in the atmosphere and are increasingly vulnerable to thaw as high-latitude temperatures warm. Large uncertainties remain about C dynamics following permafrost thaw in boreal peatlands. We used a chronosequence approach to measure C stocks in forested permafrost plateaus (forest) and thawed permafrost bogs, ranging in thaw age from young (<10 years) to old (>100 years) from two interior Alaska chronosequences. Permafrost originally aggraded simultaneously with peat accumulation (syngenetic permafrost) at both sites. We found that upon thaw, C loss of the forest peat C is equivalent to ~30% of the initial forest C stock and is directly proportional to the prethaw C stocks. Our model results indicate that permafrost thaw turned these peatlands into net C sources to the atmosphere for a decade following thaw, after which post-thaw bog peat accumulation returned sites to net C sinks. It can take multiple centuries to millennia for a site to recover its prethaw C stocks; the amount of time needed for them to regain their prethaw C stocks is governed by the amount of C that accumulated prior to thaw. Consequently, these findings show that older peatlands will take longer to recover prethaw C stocks, whereas younger peatlands will exceed prethaw stocks in a matter of centuries. We conclude that the loss of sporadic and discontinuous permafrost by 2100 could result in a loss of up to 24 Pg of deep C from permafrost peatlands.

[The processes of methane formation and oxidation in the soils of the Russian arctic tundra].

PubMed

Berestovskaia, Iu Iu; Rusanov, I I; Vasil'eva, L V; Pimenov, N V

2005-01-01

Methane emission from the following types of tundra soils was studied: coarse humic gleyey loamy cryo soil, peaty gley soil, and peaty gleyey midloamy cryo soil of the arctic tundra. All the soils studied were found to be potential sources of atmospheric methane. The highest values of methane emission were recorded in August at a soil temperature of 8-10 degrees C. Flooded parcels were the sources of atmospheric methane throughout the observation period. The rates of methane production and oxidation in tundra soils of various types at 5 and 15 degrees C were studied by the radioisotope method. Methane oxidation was found to occur in bog water, in the green part of peat moss, and in all the soil horizons studied. Methane formation was recorded in the horizons of peat, in clay with plant roots, and in peaty moss dust of the bogey parcels. At both temperatures, the methane oxidation rate exceeded the rate of methane formation in all the horizons of the mossy-lichen tundra and of the bumpy sinkhole complex. Methanogenesis prevailed only in a sedge-peat moss bog at 15 degrees C. Enrichment bacterial cultures oxidizing methane at 5 and 15 degrees C were obtained. Different types of methanotrophic bacteria were shown to be responsible for methane oxidation under these conditions. A representative of type I methylotrophs oxidized methane at 5 degrees C, and Methylocella tundrae, a psychroactive representative of an acidophilic methanotrophic genus Methylocella, at 15 degrees C.

High methane emissions dominated annual greenhouse gas balances 30 years after bog rewetting

NASA Astrophysics Data System (ADS)

Vanselow-Algan, M.; Schmidt, S. R.; Greven, M.; Fiencke, C.; Kutzbach, L.; Pfeiffer, E.-M.

2015-07-01

Natural peatlands are important carbon sinks and sources of methane (CH4). In contrast, drained peatlands turn from a carbon sink to a carbon source and potentially emit nitrous oxide (N2O). Rewetting of peatlands thus potentially implies climate change mitigation. However, data about the time span that is needed for the re-establishment of the carbon sink function by restoration are scarce. We therefore investigated the annual greenhouse gas (GHG) balances of three differently vegetated sites of a bog ecosystem 30 years after rewetting. All three vegetation communities turned out to be sources of carbon dioxide (CO2) ranging between 0.6 ± 1.43 t CO2 ha-2 yr-1 (Sphagnum-dominated vegetation) and 3.09 ± 3.86 t CO2 ha-2 yr-1 (vegetation dominated by heath). While accounting for the different global warming potential (GWP) of CO2, CH4 and N2O, the annual GHG balance was calculated. Emissions ranged between 25 and 53 t CO2-eq ha-1 yr-1 and were dominated by large emissions of CH4 (22-51 t CO2-eq ha-1 yr-1), with highest rates found at purple moor grass (Molinia caerulea) stands. These are to our knowledge the highest CH4 emissions so far reported for bog ecosystems in temperate Europe. As the restored area was subject to large fluctuations in the water table, we assume that the high CH4 emission rates were caused by a combination of both the temporal inundation of the easily decomposable plant litter of purple moor grass and the plant-mediated transport through its tissues. In addition, as a result of the land use history, mixed soil material due to peat extraction and refilling can serve as an explanation. With regards to the long time span passed since rewetting, we note that the initial increase in CH4 emissions due to rewetting as described in the literature is not inevitably limited to a short-term period.

Nutrient Addition Leads to a Weaker CO2 Sink and Higher CH4 Emissions through Vegetation-Microclimate Feedbacks at Mer Bleue Bog, Canada

NASA Astrophysics Data System (ADS)

Bubier, J. L.; Arnkil, S.; Humphreys, E.; Juutinen, S.; Larmola, T.; Moore, T. R.

2015-12-01

Atmospheric nitrogen (N) deposition has led to nutrient enrichment in wetlands globally, affecting plant community composition, carbon (C) cycling, and microbial dynamics. Nutrient-limited boreal bogs are long-term sinks of carbon dioxide (CO2), but sources of methane (CH4), an important greenhouse gas. We fertilized Mer Bleue Bog, a Sphagnum moss and evergreen shrub-dominated ombrotrophic bog near Ottawa, Ontario, for 10-15 years with N as NO3 and NH4 at 5, 10 and 20 times ambient N deposition (0.6-0.8 g N m-2 y-1), with and without phosphorus (P) and potassium (K). Treatments were applied to triplicate plots (3 x 3 m) from May - August 2000-2015 and control plots received distilled water. We measured net ecosystem CO2 exchange (NEE), ecosystem photosynthesis and respiration, and CH4 flux with climate-controlled chambers; leaf-level CO2 exchange and biochemistry; substrate-induced respiration, CH4 production and consumption potentials with laboratory incubations; plant species composition and abundance; and microclimate (peat temperature, moisture, light interception). After 15 years, we have found that NEE has decreased, and CH4 emissions have increased, in the highest nutrient treatments owing to changes in vegetation, microtopography, and peat characteristics. Vegetation changes include a loss of Sphagnum moss and introduction of new deciduous species. Simulated atmospheric N deposition has not benefitted the photosynthetic apparatus of the dominant evergreen shrubs, but resulted in higher foliar respiration, contributing to a weaker ecosystem CO2 sink. Loss of moss has led to wetter near-surface substrate, higher rates of decomposition and CH4 emission, and a shift in microbial communities. Thus, elevated atmospheric deposition of nutrients may endanger C storage in peatlands through a complex suite of feedbacks and interactions among vegetation, microclimate, and microbial communities.

Fire severity is more sensitive to low fuel moisture content on Calluna heathlands than on peat bogs.

PubMed

Grau-Andrés, Roger; Davies, G Matt; Gray, Alan; Scott, E Marian; Waldron, Susan

2018-03-01

Moorland habitats dominated by the dwarf shrub Calluna vulgaris provide important ecosystem services. Drought is projected to intensify throughout their range, potentially leading to increased fire severity as moisture is a key control on severity. We studied the effect of low fuel moisture content (FMC) on fire severity by using 2×2m rain-out shelters prior to completing 19 experimental fires in two sites in Scotland (UK): a dry heath with thin organic soils and a raised bog with deep, saturated peat, both dominated by Calluna vulgaris. Reduced FMC of the moss and litter (M/L) layer at both sites, and the soil moisture of the dry heath, increased fire-induced consumption of the M/L layer and soil heating at both sites. Increase in fire severity was greater at the dry heath than at the raised bog, e.g. average maximum temperatures at the soil surface increased from 31°C to 189°C at the dry heath, but only from 10°C to 15°C at the raised bog. Substantial M/L layer consumption was observed when its FMC was below 150%. This led to larger seasonal and daily soil temperature fluctuation, particularly at the dry heath during warm months. The results suggest that low FMC following predicted changes in climate are likely to increase wildfire severity and that the impact on vegetation composition and carbon stores may be greater at heathlands than at peatlands. Managed burning aiming to minimise fire severity (e.g. ignition of the M/L layer and exposure to lethal temperatures of ericoid seeds) should be carried out when the FMC of the M/L layer is above 150% and the FMC of the soil is above 200-300%. Copyright © 2017 Elsevier B.V. All rights reserved.

Composition of essential oils isolated from the needles of Pinus uncinata and P. uliginosa grown in Poland.

PubMed

Bonikowski, Radosław; Celiński, Konrad; Wojnicka-Półtorak, Aleksandra; Maliński, Tomasz

2015-02-01

The compositions of mountain pine (Pinus uncinata) and peat-bog pine (P. uliginosa) needle essential oils were investigated. Enantiomeric compositions of selected monoterpene hydrocarbons were also examined. Respectively, fifty-three and seventy-six components of the essential oils were identified using GC-MS and retention indexes. The main group of essential oil components of mountain pine needles were monoterpenes, and bornyl acetate constituted approximately 30% (46.3 g/100 g) of the oil. In peat-bog pine essential oil, monoterpenes and sesquiterpenes exhibited a similar content (ca. 40%). Bornyl acetate and α-pinene were the main constituents of both essential oils. In the essential oil of P. uncinata needles, limonene, camphene, myrcene and (E)-β-caryophyllene were also noticeable, while in the essential oil of P. uliginosa needles, Δ-car-3-ene, (E)-β-caryophyllene, germacrene D, δ-cadinene, germacrene D 4-ol and α-cadinol were present in notable quantities. In both essential oils, borneol propionate, isobutyrate, 2-methylbutyrate and isovalerate were detected. Their presence was confirmed by synthesis and analysis of the standards; retention indexes on a non-polar column are published herein.

Remote sensing of seasonal light use efficiency in temperate bog ecosystems.

PubMed

Tortini, R; Coops, N C; Nesic, Z; Christen, A; Lee, S C; Hilker, T

2017-08-17

Despite storing approximately half of the atmosphere's carbon, estimates of fluxes between wetlands and atmosphere under current and future climates are associated with large uncertainties, and it remains a challenge to determine human impacts on the net greenhouse gas balance of wetlands at the global scale. In this study we demonstrate that the relationship between photochemical reflectance index, derived from high spectral and temporal multi-angular observations, and vegetation light use efficiency was strong (r 2  = 0.64 and 0.58 at the hotspot and darkspot, respectively), and can be utilized to estimate carbon fluxes from remote at temperate bog ecosystems. These results improve our understanding of the interactions between vegetation physiology and spectral characteristics to understand seasonal magnitudes and variations in light use efficiency, opening new perspectives on the potential of this technique over extensive areas with different landcover.

Forest condition in Latvia

Treesearch

Madis Sipols

1998-01-01

Systematic assessment and observation (survey, inventory) of forests in Latvia has been underway since the 1700's. Latvia's forests are in the boreal/temperate forest zone and cover 44 percent of the country. Forest growing conditions are subdivided into five site class types: forests on dry mineral, wet mineral, wet peat, drained mineral, drained peat soils...

Spatial Heterogeneity in the Properties of High-Moor Peat Soils under Local Pyrogenesis in Northeastern Sakhalin

NASA Astrophysics Data System (ADS)

Lipatov, D. N.; Shcheglov, A. I.; Manakhov, D. V.; Brekhov, P. T.

2016-02-01

The structure and properties of oligotrophic peat, oligotrophic peat gley, and pyrogenic oligotrophic peat soils identified on a plot 0.5 km2 in area in the northeast of Sakhalin Island have been studied. The vertical distributions of physicochemical, chemical, and ecotoxicological parameters in the profiles of some bog soil groups have been considered. An increase in ash content, a less acid reaction, and a deficit of available nitrogen and potassium have been revealed in the upper horizons of pyrogenic soils. No accumulation of mobile heavy metals is manifested in the pyrogenic horizons of peat soils. Statistical parameters of the spatial variation in pHKCl and total acidity, as well as the contents of ash, available phosphorus, exchangeable potassium, ammonium and nitrate nitrogen, mobile heavy metals (Cr, Ni, Cu, Zn, Cd, Pb), and benzo[ a]pyrene, have been calculated for the moss and sublitter horizons. The variation coefficients are 30-100% for most of the studied parameters and reach 100-200% for available phosphorus; ammonium nitrogen; and mobile Ni, Cu, Zn, and Cd. An increase in the content of benzo[ a]pyrene, although without MPC exceedance, is noted in the moss of pyrogenic soils and the peat horizons untouched by fires.

Peat resource definition and utilization in Massachusetts. Final report, Phase One

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brenninkmeyer, B.M.; Russo, J.S.

1984-10-01

To data less than five percent of Massachusetts peatlands have been developed. Ninety percent of the developed peatlands are located in the southeastern section of Massachusetts. Seventy-five percent of the developed peatlands are used for cranberry bogs. The remainder is used for horticultural peak extraction. At the present time peatland uses can be grouped into two types, consumptive and nonconsumptive. The primary consumptive uses are: (1) extraction of peat for use as or with industrial chemicals, (2) use by the horticultural industry and (3) most important under the DOE/MEOER Program, the use of peak as a fuel. The three usesmore » of peat under consumptive usage will require extraction or harvesting of peatlands. The main nonconsumptive uses are: (1) preservation of peatlands for conservation lands, (2) biomass production, (3) timber production and (4) the most important under the title of nonconsumptive uses is peatlands for agricultural crop production. These four uses require little or no peat extraction, harvesting or alteration of the wetlands. The selection and feasibility of one particular use over another is influenced by the significance of the economics and environmental concerns as well as the types and volumes of peat. 55 figures, 12 tables.« less

Combination of branched GDGTs and testate amoebae for the reconstruction of past climate change in a French peatland

NASA Astrophysics Data System (ADS)

Huguet, Arnaud; Jassey, Vincent E. J.; Laggoun-Défarge, Fatima; Derenne, Sylvie; Gilbert, Daniel; Delarue, Frédéric; Payne, Richard; Buttler, Alexandre; Mitchell, Edward A. D.

2013-04-01

Peatlands are important archives for the reconstruction of past environmental changes because of their high rates of peat accumulation due to the low rate of plant litter decomposition. Branched glycerol dialkyl glycerol tetraethers (GDGTs) are complex lipids of high molecular weight, recently discovered in soils and suggested to be produced by anaerobic bacteria. The relative distribution of branched GDGTs in soils correlates with environmental variables: the degree of methylation, expressed in the methylation index of branched tetraethers (MBT), depends on mean annual air temperature (MAAT) and to a lesser extent on soil pH, whereas the relative abundance of cyclopentyl rings of branched GDGTs, expressed in the cyclisation ratio of branched tetraethers (CBT), is related to soil pH. The MBT/CBT proxies are increasingly used for the reconstruction of past air temperatures, but have rarely been applied in peatlands. Testate amoebae are common and diverse unicellular eukaryotes in peatlands. They build shells that are preserved in peat. They are good indicators of changing environmental conditions in peatlands and are thus used in both ecological and paleoecological studies, especially for reconstructing surface moisture. The aim of this study was to examine the applicability of branched GDGTs and testate amoebae as indicators of environmental changes (temperature and moisture) in temperate peatlands. Within the PEATWARM project, both GDGTs and testate amoebae were studied at high resolution in a 4 m peat core collected in Frasne mire (French Jura Mountains) and covering the last 7,400 years BP. GDGT-inferred temperatures ranged between 8 and 12 °C until 250 cm depth and were higher than present measured mean annual air temperature (ca. 6 °C). Temperature estimates in the top part of the bog were most consistent with spring and summer mean air temperatures recorded in the peatland (ca. 11.5 °C), suggesting that branched GDGT-producing bacteria might be more active during the warmest months of the year. At 250 cm depth, reconstructed temperature showed a pronounced shift, likely reflecting both a change in climatic conditions but also in the composition of the peat. Indeed, drier conditions were indicated by testate amoebae at the bottom of the peat core, whereas wetter conditions occurred at the top. Interestingly, temperature variations inferred from MBT/CBT proxies were weakly linked with moisture variations inferred from testate amoebae until 150 cm depth (r = -0.41, p = 0.06). Therefore, the distribution of branched GDGTs might also depend on peat moisture level, in addition to air temperature and pH. Our data suggest that the joint use of MBT/CBT and testate amoebae is a promising approach to estimate past climate change, but that more research is required to calibrate and apply with confidence these proxies in peatlands.

Plant component features of forest-bog ecotones of eutrophic paludification in the south of boreal forest zone of West Siberia

NASA Astrophysics Data System (ADS)

Klimova, N. V.; Chernova, N. A.; Pologova, N. N.

2018-03-01

Paludified forests formed in transitional forest-bog zone aren’t studied enough, inspite of its high expected diversity and large areas in the south of boreal forest zone of West Siberia. In this article wet birch (Betula pubescens) forests of forest-bog ecotones of eutrophic paludification are investigated on Vasyugan plain with nutrient-rich calcareous clays as soil-forming rocks. Species diversity and ecocoenotic structure of these phytocoenoses are discussed. They correlated with wetness and nutrient-availability of habitats evaluated with indicator values of plants. The participation of hydrophylous species is increasing as wetness of habitats increasing in the forest-to-bog direction like in mesotrophic paludification series. However the number of species is higher in the phytocoenoses of eutrophic paludification. The share of species required to nutrient availability is also higher, both in number and in abundance. A lot of these species are usual for eutrophic boreal forested swamps with groundwater input and absent in forests of mesotrophic paludification. Accordingly the nutrient-availability of habitats is also higher. All these features we connect with birch to be a forest forming species instead of dark-coniferous and with the influence of nutrient-rich parent rocks, which is evident in forest-bog ecotones of Vasyugan plain gradually decreasing together with peat horizon thickening.

What rules GHG-(greenhouse gas)-fluxes in a prealpine bog - management or watertable?

NASA Astrophysics Data System (ADS)

Förster, Christoph; Drösler, Matthias

2010-05-01

Being an important sink of carbon, the small stripe of bogs in the foreland of the Alps plays an important role for the carbon balance of Germany. A big part was drained for peat-use and to get agricultural land in the last centuries. Restoration of these degraded bogs can help to rebuild this function, whereas the watertable is an important co-factor for the amount of mitigation of greenhouse gases (CO2, CH4 and N2O). To estimate GHG-balances gas-flux measurements, using the chamber method developed by Drösler (2005) were done in 2007 and 2008 on a degraded bog-meadow, which was partly rewetted in 1993 and which is still managed in large areas. This mosaic of restored, drained and managed areas showed big differences in their carbon-balances from a high source (~ 500 g CO2-C m-2 a-1) to a moderate sink (~ -200 g CO2-C m-2 a-1). Where the management was stopped in 1993, some Sphagnum-communities developed which helped to turn these areas from moderate sources (47 g CO2-C m-2 a-1) or sinks (-58 g CO2-C m-2 a-1) to permanent sinks with uptakes between (-150 and -250 g CO2-C m-2 a-1). Key words: bog, carbon-balance, greenhouse gases, restoration, watertable

Validating modelled data on major and trace element deposition in southern Germany using Sphagnum moss

NASA Astrophysics Data System (ADS)

Kempter, Heike; Krachler, Michael; Shotyk, William; Zaccone, Claudio

2017-10-01

Sphagnum mosses were collected from four ombrotrophic bogs in two regions of southern Germany: Upper Bavaria (Oberbayern, OB) and the Northern Black Forest (Nordschwarzwald, NBF). Surfaces of Sphagnum carpets were marked with plastic mesh and, one year later, plant matter was harvested and productivity determined. Major and trace element concentrations (Ag, Al, As, Ba, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, Rb, Sb, Sc, Sr, Th, Ti, Tl, U, V, Zn) were determined in acid digests using sector field ICP-MS. Up to 12 samples (40 × 40 cm) were collected per site, and 6-10 sites investigated per bog. Variation in element accumulation rates within a bog is mostly the result of the annual production rate of the Sphagnum mosses which masks not only the impact of site effects, such as microtopography and the presence of dwarf trees, but also local and regional conditions, including land use in the surrounding area, topography, etc. The difference in productivity between peat bogs results in distinctly higher element accumulation rates at the NBF bogs compared to those from OB for all studied elements. The comparison with the European Monitoring and Evaluation Program (EMEP; wet-only and total deposition) and Modelling of Air Pollutants and Ecosystem Impact (MAPESI; total deposition) data shows that accumulation rates obtained using Sphagnum are in the same range of published values for direct measurements of atmospheric deposition of As, Cd, Cu, Co, Pb, and V in both regions. The accordance is very dependent on how atmospheric deposition rates were obtained, as different models to calculate the deposition rates may yield different fluxes even for the same region. In future studies of atmospheric deposition of trace metals, both Sphagnum moss and deposition collectors have to be used on the same peat bog and results compared. Antimony, however, shows considerable discrepancy, because it is either under-estimated by Sphagnum moss or over-estimated by both atmospheric deposition models. Atmospheric deposition data obtained from sampling in open fields is unlikely to always perfectly match data obtained using living Sphagnum moss from bogs. In fact, plant uptake and biochemical utilization by living moss may affect accumulation rates of those elements that are essential for plant nutrition (macro and micronutrients), which is clearly seen in the data presented here for Mn, Fe and Zn. Furthermore, Sphagnum moss is a unique receptor, with its characteristic roughness and chemical complexity. These two aspects, combined with conditions found on the bog surface (variations in microtopography, shrubs, trees, wetness, snow cover, etc.), result in a unique type of interception and retention. Despite all these factors, the comparison with modelled data shows that Sphagnum moss is a good indicator of atmospheric deposition at least in a semi-quantitative manner and certainly reflects inputs to terrestrial ecosystems.

Smouldering bog wildfires and possible implications in palaeoenvironmental reconstructions

NASA Astrophysics Data System (ADS)

Zaccone, C.; Rein, G.; D'Orazio, V.; Hadden, R.; Belcher, C. M.; Miano, T. M.

2012-04-01

Ombrotrophic (i.e., rainwater-fed) peat bogs have been recognized as providing excellent records of past environmental changes over the last millennia. They are well known to provide information on both climatic and vegetational changes, and the deposition of organic and inorganic pollutants from anthropogenic vs. lithogenic sources. Whether they also record well past fire activity is an unresolved issue to date. Peatland ecosystems are most at risk from smouldering fires, especially in drought conditions. Smouldering fires are slow, low temperature, flameless and the most persistent form of combustion of organic matter (OM) in porous form. It is known to consume dozen of times more peat mass than flaming fires. Importantly, the in-depth oxidation reaction in smouldering leaves few charred remains, which hampers their identification in palaeoenvironmental analyses. Smouldering even consumes the possible pyrogenic char produced by flaming wildfires. Most studies on smouldering peatland fires to date have focused on ignition and carbon losses/emissions, leaving a significant gap in our understanding of OM changes following fires. In the present work, we present new data which suggest that variations in the chemical signature of OM in peatlands provides a possibility of identifying past peatland fires. In particular, we show results from a laboratory study about the physical, chemical and spectroscopic changes in OM features following a smouldering fire. We initiated a smouldering fire on top of three sphagnum peat columns (26 cm deep) each having a different initial moisture content (MC) designed to reflect dry conditions (55% MC), undisturbed conditions (90% MC), and wet conditions (210% MC). The fires were allowed to propagate downwards until they self-extinguished at some distance from the top. After the fire, we tracked chemical variations in the residual columns to determine the possible signature of natural past smouldering peatland fires. The analysis shows a consistent variation in the vertical direction of chemical markers below the point at which the fire front propagated the columns. The depth over which the chemical markers vary is apparent down to 5 cm in 55% MC (the whole residual column), and 8 cm deep in 90% MC. No significant variation of any of the chemical parameters was observed in the 210% MC column. The results of this study show that smouldering fires could occur also when bogs are in undisturbed hydrological conditions (e.g., near 100%MC), and that zone affected by smouldering fire is revealed by the presence of: 1) a strong increases of pH and ash content; 2) higher contents of aromatic and condensed molecules (as suggested by higher C/H values and by fluorescence spectra); 3) higher total N content leading to a decrease in C/N ratio. These data show potential to track similar variations in cores taken from peat bogs where they may serve as new proxies for the identification of past fire events. Moreover, these findings suggest the possibility that similar chemical and physical signatures detected in previous peatland cores may have been ascribed to the wrong past climatic or hydrological variations, as fire induced changes had not been considered before. In particular, peaks in ash content, such as those observed in our study (e.g.. ca. 13% in the 90% MC residue vs. 3% in the undisturbed peat), have in the past been ascribed to an increase of either dust depositions or mineralization processes typically linked to climatic changes. Similarly, large variations in pH values (e.g., >6 in the 90% MC residue vs.

Temporal and Spatial Variation in Peatland Carbon Cycling and Implications for Interpreting Responses of an Ecosystem-Scale Warming Experiment

Treesearch

Natalie A. Griffiths; Paul J. Hanson; Daniel M. Ricciuto; Colleen M. Iversen; Anna M. Jensen; Avni Malhotra; Karis J. McFarlane; Richard J. Norby; Khachik Sargsyan; Stephen D. Sebestyen; Xiaoying Shi; Anthony P. Walker; Eric J. Ward; Jeffrey M. Warren; David J. Weston

2017-01-01

We are conducting a large-scale, long-term climate change response experiment in an ombrotrophic peat bog in Minnesota to evaluate the effects of warming and elevated CO2 on ecosystem processes using empirical and modeling approaches. To better frame future assessments of peatland responses to climate change, we characterized and compared spatial...

A Holocene History of Permafrost Dynamics, Carbon Sequestration, and Hydrological Changes at Beretta Bog, Mackenzie River Basin

NASA Astrophysics Data System (ADS)

Von Ness, K.; Loisel, J.; Beilman, D. W.; Kaiser, K.

2017-12-01

The Mackenzie River Basin (MRB) is one of the world's largest permafrost peatland areas. This region contains dense soil carbon deposits and is home of the largest Canadian Arctic watershed. However, much remains to be known about the timing of permafrost initiation and the moisture changes that have affected soil development across this region throughout the Holocene. Peatland hydroclimatic conditions, which impact permafrost freezing and thawing as well as carbon sequestration rates, are relatively undocumented in peat-based paleoreconstructions. To provide further insight into the region's permafrost dynamics and the moisture changes associated with them, this study presents a permafrost initiation history and paleohydrological reconstruction of Beretta Bog, MRB that dates back to roughly 9000 cal BP. We explore the use of lichens as a bio-indicator of permafrost formation by quantifying the abundance of lichen-specific carbohydrates (mannose and galactose) in the peat profile. Testate amoebae, plant macrofossils, and carbon and oxygen isotopes (δ13C and δ18O) are also being analyzed at high resolution to reconstruct past changes in soil moisture and temperature. To our knowledge this study will constitute the first high-resolution paleohydrological reconstruction for this region. While carbohydrate analysis is underway, high C/N values from 6000 cal BP to present are temporarily used as an indicator for permafrost aggradation. Carbon accumulation rates of the core are highest prior to 6000 cal BP (during the Holocene Thermal Maximum) and relatively lower until around 1000 cal BP; we hypothesize this period of slow accumulation corresponds to permafrost aggradation. Preliminary results of our δ13C analysis corroborate testate assemblages as a proxy suitable for revealing moisture changes in permafrost peat. In the upper core, our analysis shows that more negative δ13C values, which reflect drier conditions, correlate to higher percentages of A. flavum and H. papilio, two moderate/dry taxa. Likewise, less negative δ13C values correlate with larger percentages of N. militaris, T. arcula, and H. elegans, three moderate/wet taxa. Overall, the multiple proxies used in this study will provide a detailed understanding of the permafrost dynamics and paleohydrological characteristics of Beretta Bog.

Small spatial variability in methane emission measured from a wet patterned boreal bog

NASA Astrophysics Data System (ADS)

Korrensalo, Aino; Männistö, Elisa; Alekseychik, Pavel; Mammarella, Ivan; Rinne, Janne; Vesala, Timo; Tuittila, Eeva-Stiina

2018-03-01

We measured methane fluxes of a patterned bog situated in Siikaneva in southern Finland from six different plant community types in three growing seasons (2012-2014) using the static chamber method with chamber exposure of 35 min. A mixed-effects model was applied to quantify the effect of the controlling factors on the methane flux. The plant community types differed from each other in their water level, species composition, total leaf area (LAITOT) and leaf area of aerenchymatous plant species (LAIAER). Methane emissions ranged from -309 to 1254 mg m-2 d-1. Although methane fluxes increased with increasing peat temperature, LAITOT and LAIAER, they had no correlation with water table or with plant community type. The only exception was higher fluxes from hummocks and high lawns than from high hummocks and bare peat surfaces in 2013 and from bare peat surfaces than from high hummocks in 2014. Chamber fluxes upscaled to ecosystem level for the peak season were of the same magnitude as the fluxes measured with the eddy covariance (EC) technique. In 2012 and in August 2014 there was a good agreement between the two methods; in 2013 and in July 2014, the chamber fluxes were higher than the EC fluxes. Net fluxes to soil, indicating higher methane oxidation than production, were detected every year and in all community types. Our results underline the importance of both LAIAER and LAITOT in controlling methane fluxes and indicate the need for automatized chambers to reliably capture localized events to support the more robust EC method.

Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands.

PubMed

Jones, Miriam C; Harden, Jennifer; O'Donnell, Jonathan; Manies, Kristen; Jorgenson, Torre; Treat, Claire; Ewing, Stephanie

2017-03-01

Permafrost peatlands store one-third of the total carbon (C) in the atmosphere and are increasingly vulnerable to thaw as high-latitude temperatures warm. Large uncertainties remain about C dynamics following permafrost thaw in boreal peatlands. We used a chronosequence approach to measure C stocks in forested permafrost plateaus (forest) and thawed permafrost bogs, ranging in thaw age from young (<10 years) to old (>100 years) from two interior Alaska chronosequences. Permafrost originally aggraded simultaneously with peat accumulation (syngenetic permafrost) at both sites. We found that upon thaw, C loss of the forest peat C is equivalent to ~30% of the initial forest C stock and is directly proportional to the prethaw C stocks. Our model results indicate that permafrost thaw turned these peatlands into net C sources to the atmosphere for a decade following thaw, after which post-thaw bog peat accumulation returned sites to net C sinks. It can take multiple centuries to millennia for a site to recover its prethaw C stocks; the amount of time needed for them to regain their prethaw C stocks is governed by the amount of C that accumulated prior to thaw. Consequently, these findings show that older peatlands will take longer to recover prethaw C stocks, whereas younger peatlands will exceed prethaw stocks in a matter of centuries. We conclude that the loss of sporadic and discontinuous permafrost by 2100 could result in a loss of up to 24 Pg of deep C from permafrost peatlands. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Insights and issues with estimating Holocene peatland carbon stocks: a synthesis and review

NASA Astrophysics Data System (ADS)

Loisel, Julie; Yu, Zicheng

2014-05-01

Of all terrestrial ecosystems, peatlands are arguably the most efficient at sequestering carbon (C) over long time scales. However, ongoing and projected climate change could shift the balance between peat production and organic matter decomposition, potentially impacting the peat C sink capacity and modifying peat C fluxes to the atmosphere. Yet, the sign and magnitude of the peatland - C - climate feedback remain uncertain and difficult to assess because of large uncertainties in regional peat C stocks and limited understanding of peatland responses to climate change. Here we present results from the most comprehensive compilation of Holocene peat soil properties with associated carbon (C) and nitrogen (N) accumulation rates for northern peatlands. Our database consists of 268 peat cores from 215 sites located north of 45N. It encompasses regions within which peat C data have only recently become available, such as the West Siberia Lowlands, the Hudson Bay Lowlands, Kamchatka in Far East Russia, and the Tibetan Plateau. The database is publicly available at https://peatlands.lehigh.edu. Several scaling-up methods for estimating present-day peatland C stocks are presented, and uncertainties associated with each one of them are addressed. Likewise, the assumptions for calculating peat C volumes are discussed in light of conceptual models of spatial heterogeneity in peatland structure and function. We also examine the theoretical basis and underlying assumptions for the models of peatland lateral expansion and peat vertical growth used in estimating paleo peatland C stocks. Finally, we explore the importance of the fen-to-bog transition and of permafrost aggradation on C sequestration.

Potential compensation of hydrological extremes in headwaters: case study of upper Vltava River basin, Šumava Mts., Czechia

NASA Astrophysics Data System (ADS)

Kocum, Jan; Janský, Bohumír.; Česák, Julius

2010-05-01

Increasing frequency of catastrophic flash floods and extreme droughts in recent years results in an urgent need of solving of flood protection questions and measures leading to discharge increase in dry periods. Flattening of discharge call for the use of untraditional practices as a suitable complement to classical engineering methods. These measures could be represented by gradual increase of river catchment retention capacity in headstream areas. Very favorable conditions for this research solution are concentrated to the upper part of Otava River basin (Vltava River left tributary, Šumava Mts., southwestern Czechia) representing the core zone of a number of extreme floods in Central Europe and the area with high peat land proportion. A number of automatic ultrasound and hydrostatic pressure water level gauges, climatic stations and precipitation gauges and utilization of modern equipment and methods were used in chosen experimental catchments to assess the landscape retention potential and to find out rainfall-runoff relations in this area. Successively, the detailed analysis of peat land hydrological function was carried out. The peat bogs influence on runoff conditions were assessed by thorough comparison of runoff regimes in subcatchments with different peat land proportion. The peat bog influence on hydrological process can be considered also with respect to its affecting of water quality. Therefore, hydrological monitoring was completed by ion, carbon (TOC) and oxygen isotopes balance observing within periods of high or low discharges in order to precise runoff phases separation by means of anion deficiency. Pedological survey of different soil types and textures was carried out to precise the estimation of its water capacity. Detailed analyses of extreme runoff ascending and descending phases and minimum discharges in profiles closing several subcatchments with different physical-geographic conditions show higher peak flow frequency and their shorter reaction to causal amount of precipitation in the case of highly peaty areas, therefore more distinct runoff variability of streams draining peat land localities. These findings were affirmed by geochemical approach laboratory outcomes within the meaning of significant contribution of runoff from peat lands to the total runoff during extreme flood situations. An important component of rainfall-runoff process in source areas of czech rivers represented by snow conditions was analyses very in detail by means of monitoring of snow cover height and its water equivalent in chosen experimental catchments. Outcomes of this study should markedly help with significant precising of estimation of water storage retained in a snow cover. Consecutive runoff simulations using mathematical techniques would then improve a hydrological forecast. In terms of present dyking of former channels draining peat land represented by so called peat bog revitalization partial findings refer to positive effect during mean runoff situations but their considerably negative influence on runoff process in cases of extremely high discharges. In order to achieve retention potential enhancement in source areas of czech rivers an evaluation of possible former accumulative reservoirs (used for wood floating in former times) restoration which could function for example as dry (green) polders should be considered. The system of such small storage bins could function as an alternative and supplement to greater dam reservoirs. Possible spaces for water retention are measured by geodetic total station and modelled by suitable methods in GIS software. Existing outcomes advert to the fact that the effectiveness of such reservoir system would not have to be neglecting. By implementation of these unforceable measures realized in river headstream areas it could be contributed to reduction of peak flows and to increase of water resources during extreme droughts in future.

Experimental burial inhibits methanogenesis and anaerobic decomposition in water-saturated peats.

PubMed

Blodau, Christian; Siems, Melanie; Beer, Julia

2011-12-01

A mechanistic understanding of carbon (C) sequestration and methane (CH(4)) production is of great interest due to the importance of these processes for the global C budget. Here we demonstrate experimentally, by means of column experiments, that burial of water saturated, anoxic bog peat leads to inactivation of anaerobic respiration and methanogenesis. This effect can be related to the slowness of diffusive transport of solutes and evolving energetic constraints on anaerobic respiration. Burial lowered decomposition constants in homogenized peat sand mixtures from about 10(-5) to 10(-7) yr(-1), which is considerably slower than previously assumed, and methanogenesis slowed down in a similar manner. The latter effect could be related to acetoclastic methanogenesis approaching a minimum energy quantum of -25 kJ mol(-1) (CH(4)). Given the robustness of hydraulic properties that locate the oxic-anoxic boundary near the peatland surface and constrain solute transport deeper into the peat, this effect has likely been critical for building the peatland C store and will continue supporting long-term C sequestration in northern peatlands even under moderately changing climatic conditions.

Hydrology and Geostatistics of a Vermont, USA Kettlehole Peatland

NASA Astrophysics Data System (ADS)

Mouser, Paula J.; Hession, W. Cully; Rizzo, Donna M.; Gotelli, Nicholas J.

2005-01-01

The ability to predict the response of peatland ecosystems to hydrologic changes is imperative for successful conservation and remediation efforts. We studied a 1.25-ha Vermont kettlehole bog for one year (September 2001-October 2002) to identify hydrologic controls, temporal and spatial variability in flow regimes, and to link hydrologic processes to density of the carnivorous plant ( Sarracenia purpurea), an ombrotrophic bog specialist. Using a spatial array of nested piezometers, we measured surface and subsurface flow in shallow peat and surrounding mineral soil. Our unique sampling array was based on a repeated measures factorial design with: (1) incremental distances from a central kettlehole pond; (2) equal distances between piezometers; and (3) at three depths from the peat surface. Local flow patterns in the peat were controlled by snowpack storage during winter and spring months and by evapotranspiration and pond water elevation during summer and fall months. Hydraulic head values showed a local reversal within the peat during spring months which was reflected in higher chemical constituent concentrations in these wells. On a regional scale, higher permeable soils diverted groundwater beneath the peatland to a nearby wetland complex. Horizontal water gradient magnitudes were larger in zones where the peatland was perched above regional groundwater and smaller in zones where a hydraulic connection existed between the peatland and the regional groundwater. The density of pitcher plants ( S. purpurea) is strongly correlated to the distance from a central pond, [Fe 3+], [Na +], [Cl -], and [SO42-]. The pH, conductivity, and [Ca 2+] had significant effects of depth and time with horizontal distance correlations between 20 and 26 m. The pH samples had temporal correlations between 27 and 79 days. The link between pitcher plants and ion chemistry; significant effects of peatland chemistry on distance, depth, and time; and spatial and temporal correlations are important considerations for peatland restoration strategies.

Long-term carbon and nitrogen dynamics at SPRUCE revealed through stable isotopes in peat profiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hobbie, Erik A.; Chen, Janet; Hanson, Paul J.

Peatlands encode information about past vegetation dynamics, climate, and microbial processes. Here, we used δ 15N and δ 13C patterns from 16 peat profiles to deduce how the biogeochemistry of the Marcell S1 forested bog in northern Minnesota responded to environmental and vegetation change over the past ~10 000 years. In multiple regression analyses, δ 15N and δ 13C correlated strongly with depth, plot location, C/N, %N, and each other. Correlations with %N, %C, C/N, and the other isotope accounted for 80 % of variance for δ 15N and 38 % of variance for δ 13C, reflecting N and C losses.more » In contrast, correlations with depth and topography (hummock or hollow) reflected peatland successional history and climate. Higher δ 15N in plots closer to uplands may reflect upland-derived DON inputs and accompanying shifts in N dynamics in the lagg drainage area surrounding the bog. The Suess effect (declining δ 13CO 2 since the Industrial Revolution) lowered δ 13C in recent surficial samples. High δ 15N from –35 to –5 cm probably indicated the depth of ectomycorrhizal activity after tree colonization of the peatland over the last 400 years, as confirmed by the occasional presence of wood down to –35 cm depth. High δ 13C at ~4000 years BP (–65 to –105 cm) could reflect a transition at that time to slower rates of peat accumulation, when 13C discrimination during peat decomposition may increase in importance. Low δ 13C and high δ 15N at –213 and –225 cm (~8500 years BP) corresponded to a warm period during a sedge-dominated rich fen stage. As a result, the above processes appear to be the primary drivers of the observed isotopic patterns, whereas there was no clear evidence for methane dynamics influencing δ 13C patterns.« less

Long-term carbon and nitrogen dynamics at SPRUCE revealed through stable isotopes in peat profiles

NASA Astrophysics Data System (ADS)

Hobbie, Erik A.; Chen, Janet; Hanson, Paul J.; Iversen, Colleen M.; McFarlane, Karis J.; Thorp, Nathan R.; Hofmockel, Kirsten S.

2017-05-01

Peatlands encode information about past vegetation dynamics, climate, and microbial processes. Here, we used δ15N and δ13C patterns from 16 peat profiles to deduce how the biogeochemistry of the Marcell S1 forested bog in northern Minnesota responded to environmental and vegetation change over the past ˜ 10 000 years. In multiple regression analyses, δ15N and δ13C correlated strongly with depth, plot location, C / N, %N, and each other. Correlations with %N, %C, C / N, and the other isotope accounted for 80 % of variance for δ15N and 38 % of variance for δ13C, reflecting N and C losses. In contrast, correlations with depth and topography (hummock or hollow) reflected peatland successional history and climate. Higher δ15N in plots closer to uplands may reflect upland-derived DON inputs and accompanying shifts in N dynamics in the lagg drainage area surrounding the bog. The Suess effect (declining δ13CO2 since the Industrial Revolution) lowered δ13C in recent surficial samples. High δ15N from -35 to -55 cm probably indicated the depth of ectomycorrhizal activity after tree colonization of the peatland over the last 400 years, as confirmed by the occasional presence of wood down to -35 cm depth. High δ13C at ˜ 4000 years BP (-65 to -105 cm) could reflect a transition at that time to slower rates of peat accumulation, when 13C discrimination during peat decomposition may increase in importance. Low δ13C and high δ15N at -213 and -225 cm ( ˜ 8500 years BP) corresponded to a warm period during a sedge-dominated rich fen stage. The above processes appear to be the primary drivers of the observed isotopic patterns, whereas there was no clear evidence for methane dynamics influencing δ13C patterns.

Long-term carbon and nitrogen dynamics at SPRUCE revealed through stable isotopes in peat profiles

DOE PAGES

Hobbie, Erik A.; Chen, Janet; Hanson, Paul J.; ...

2017-05-17

Peatlands encode information about past vegetation dynamics, climate, and microbial processes. Here, we used δ 15N and δ 13C patterns from 16 peat profiles to deduce how the biogeochemistry of the Marcell S1 forested bog in northern Minnesota responded to environmental and vegetation change over the past ~10 000 years. In multiple regression analyses, δ 15N and δ 13C correlated strongly with depth, plot location, C/N, %N, and each other. Correlations with %N, %C, C/N, and the other isotope accounted for 80 % of variance for δ 15N and 38 % of variance for δ 13C, reflecting N and C losses.more » In contrast, correlations with depth and topography (hummock or hollow) reflected peatland successional history and climate. Higher δ 15N in plots closer to uplands may reflect upland-derived DON inputs and accompanying shifts in N dynamics in the lagg drainage area surrounding the bog. The Suess effect (declining δ 13CO 2 since the Industrial Revolution) lowered δ 13C in recent surficial samples. High δ 15N from –35 to –5 cm probably indicated the depth of ectomycorrhizal activity after tree colonization of the peatland over the last 400 years, as confirmed by the occasional presence of wood down to –35 cm depth. High δ 13C at ~4000 years BP (–65 to –105 cm) could reflect a transition at that time to slower rates of peat accumulation, when 13C discrimination during peat decomposition may increase in importance. Low δ 13C and high δ 15N at –213 and –225 cm (~8500 years BP) corresponded to a warm period during a sedge-dominated rich fen stage. As a result, the above processes appear to be the primary drivers of the observed isotopic patterns, whereas there was no clear evidence for methane dynamics influencing δ 13C patterns.« less

Ecosystem Model Performance at Wetlands: Results from the North American Carbon Program Site Synthesis

NASA Astrophysics Data System (ADS)

Sulman, B. N.; Desai, A. R.; Schroeder, N. M.; NACP Site Synthesis Participants

2011-12-01

Northern peatlands contain a significant fraction of the global carbon pool, and their responses to hydrological change are likely to be important factors in future carbon cycle-climate feedbacks. Global-scale carbon cycle modeling studies typically use general ecosystem models with coarse spatial resolution, often without peatland-specific processes. Here, seven ecosystem models were used to simulate CO2 fluxes at three field sites in Canada and the northern United States, including two nutrient-rich fens and one nutrient-poor, sphagnum-dominated bog, from 2002-2006. Flux residuals (simulated - observed) were positively correlated with measured water table for both gross ecosystem productivity (GEP) and ecosystem respiration (ER) at the two fen sites for all models, and were positively correlated with water table at the bog site for the majority of models. Modeled diurnal cycles at fen sites agreed well with eddy covariance measurements overall. Eddy covariance GEP and ER were higher during dry periods than during wet periods, while model results predicted either the opposite relationship or no significant difference. At the bog site, eddy covariance GEP had no significant dependence on water table, while models predicted higher GEP during wet periods. All models significantly over-estimated GEP at the bog site, and all but one over-estimated ER at the bog site. Carbon cycle models in peatland-rich regions could be improved by incorporating better models or measurements of hydrology and by inhibiting GEP and ER rates under saturated conditions. Bogs and fens likely require distinct treatments in ecosystem models due to differences in nutrients, peat properties, and plant communities.

A Mega-fire event in Central Russia: fire weather, radiative, and optical properties of the atmosphere, and consequences for subboreal forest plants

Treesearch

Nataly Y. Chubarova; Nickolay G. Prilepsky; Alexei N. Rublev; Allen R. Riebau

2009-01-01

In 2002, a major drought and prolonged high temperatures occurred in central Russia that resulted in unprecedented wildland fires. These fires occurred under extreme fire danger conditions and were impossible for the Russian authorities to extinguish. It is perhaps somewhat unique that the fires were first burning peat bogs and later forests, causing very massive smoke...

Sesquiterpene lactones in Arnica montana: helenalin and dihydrohelenalin chemotypes in Spain.

PubMed

Perry, Nigel B; Burgess, Elaine J; Rodríguez Guitián, Manuel A; Romero Franco, Rosa; López Mosquera, Elvira; Smallfield, Bruce M; Joyce, Nigel I; Littlejohn, Roger P

2009-05-01

An analytical RPLC method for sesquiterpene lactones in Arnica montana has been extended to include quantitative analyses of dihydrohelenalin esters. LC-ESI-MS-MS distinguished the isomeric helenalin and dihydrohelenalin esters. The dihydrohelenalin esters have lower response factors for UV detection than do helenalin esters, which must be taken into account for quantitative analyses. Analyses of flowers from 16 different wild populations of A. montana in Spain showed differing proportions of helenalin and dihydrohelenalin esters. For the first time a chemotype with high levels of helenalin esters (total helenalins 5.2-10.3 mg/g dry weight) is reported in Spanish A. montana. These samples were from heath lands at high altitude (1330-1460 m), whereas samples from meadows and peat bogs at lower altitudes were the expected chemotype with high levels of dihydrohelenalin esters (total dihydrohelenalins 10.9-18.2 mg/g). The phenolic compounds, both flavonoid glycosides and caffeoylquinic acids, in Spanish A. montana are reported for the first time. The levels of several of these compounds differed significantly between samples from heath lands and samples from peat bogs or meadows, with the heath land samples being most similar to central European A. montana in their phenolic composition. Copyright Georg Thieme Verlag KG Stuttgart. New York.

On the presence of plutonium in Madagascar following the SNAP-9A satellite failure.

PubMed

Rääf, C; Holm, E; Rabesiranana, N; Garcia-Tenorio, R; Chamizo, E

2017-10-01

This study examined the 238 Pu and 239+240 Pu activity concentration and the 240 Pu/ 239 Pu atomic ratio in peat bogs sampled in 2012 from marshlands in central Madagascar. The purpose was to investigate the presence of plutonium isotopes, 238, 239, 240 Pu, from the 1964 satellite failure carrying a SNAP-9A radiothermal generator. With an average 238 Pu/ 239+240 Pu activity ratio of 0.165 ± 0.02 (decay corrected to 1964), the peat bogs in Madagascar exhibit similar values as the ones found in the southeastern African continent, except they are one order of magnitude higher than expected (0.025) from global fallout in the Southern Hemisphere. The 240 Pu/ 239 Pu atomic ratio showed a distinct decrease for layers dating back to the mid-1960s (down to 0.069 compared with an anticipated ratio of 0.17 for global fallout), indicating that the SNAP-9A failure also resulted in an elevated deposition of 239 Pu. The obtained results demonstrate that further Pu analysis in Madagascar and in southeastern continental Africa is necessary to fully account for the regional Pu deposition from the SNAP-9A event. Copyright © 2017 Elsevier Ltd. All rights reserved.

Atmospheric Deposition of Indium in the Northeastern United States: Flux and Historical Trends.

PubMed

White, Sarah Jane O; Keach, Carrie; Hemond, Harold F

2015-11-03

The metal indium is an example of an increasingly important material used in electronics and new energy technologies, whose environmental behavior and toxicity are poorly understood despite increasing evidence of detrimental health impacts and human-induced releases to the environment. In the present work, the history of indium deposition from the atmosphere is reconstructed from its depositional record in an ombrotrophic bog in Massachusetts. A novel freeze-coring technique is used to overcome coring difficulties posed by woody roots and peat compressibility, enabling retrieval of relatively undisturbed peat cores dating back more than a century. Results indicate that long-range atmospheric transport is a significant pathway for the transport of indium, with peak concentrations of 69 ppb and peak fluxes of 1.9 ng/cm2/yr. Atmospheric deposition to the bog began increasing in the late 1800s/early 1900s, and peaked in the early 1970s. A comparison of deposition data with industrial production and emissions estimates suggests that both coal combustion and the smelting of lead, zinc, copper, and tin sulfides are sources of indium to the atmosphere in this region. Deposition appears to have decreased considerably since the 1970s, potentially a visible effect of particulate emissions controls instated in North America during that decade.

Natural chloroform emissions from the blanket peat bogs in the vicinity of Mace Head, Ireland over a 14-year period

NASA Astrophysics Data System (ADS)

Simmonds, P. G.; Derwent, R. G.; Manning, A. J.; O'Doherty, S.; Spain, G.

2010-03-01

Simultaneous chloroform (CHCl 3) emission and ozone (O 3) deposition are regularly observed under nocturnal inversions during the summer months from and to the peat bogs in the vicinity of the Mace Head Atmospheric Research Station, Connemara, Co Galway, Ireland. Emissions were estimated using the nocturnal box model applied to routine atmospheric observations collected over a 14-year period from 1995 to 2008. Strict criteria were applied in the selection of events of low wind speed, under a stable night-time inversion layer in baseline air conditions, with no transport from Europe. The mean peatland CHCl 3 flux was 2.91 μg m -2 h -1 with highly variable fluxes ranging from 0.44 to 12.94 μg m -2 h -1. These fluxes are generally larger than those reported previously for similar biomes and if representative would make a significant contribution to the global estimated source of CHCl 3. Fluxes were not strongly correlated with either atmospheric temperature or the level of precipitation. Over the 14-year period there appears to have been a small increase in overall CHCl 3 emissions, although we stress that the nocturnal box model has a number of limitations and assumptions which should be taken into account.

Ecological study of peat landforms in Canada and Alaska

NASA Technical Reports Server (NTRS)

Glaser, Paul H.

1989-01-01

Over 20 percent of the land surface of Canada and Alaska is covered by peatlands, which may be defined as any waterlogged ecosystem with a minimum thickness of 20 cm of organic matter in the soil. Past investigations have demonstrated the value of aerial photographs in identifying the major vegetation types and analyzing the biotic and hydrogeologic processes that control the development of these peatlands. In the present study, LANDSAT TM imagery was used in conjunction with field studies to determine the utility of this satellite sensor for detecting these important processes. Although the vegetation landforms within these major peat basins are visible on aerial photographs, LANDSAT TM imagery provides essential new evidence for their analysis. Spectral data from the LANDSAT TM system provides: (1) synoptic views of the patterns across large portions of these peat basins, indicating important physiographic controls on peatland development, (2) more sensitive detection of the major vegetation types, allowing rapid quantitative estimates to be made of their distribution and aerial extent, (3) discrimination of bog areas with potentially rapid or slow rates of peat accumulation, (4) identification of discharge zones for groundwater, which apparently represents the most important source of alkalinity in these peat basins, and (5) detection of flow patterns in water tracks that appear nearly uniform on standard aerial photographs.

Review of the inorganic geochemistry of peats and peatland waters

NASA Astrophysics Data System (ADS)

Shotyk, William

1988-06-01

The major floristic and geochemical differences between bogs, fens, and swamps are summarized, and the most common peat types described. This is followed by a critical, historical review of the literature. The methods used to measure the pH of peatland (mire) waters are examined, and the pH range of various peatland types is reported. In addition, horizontal and vertical pH variations are illustrated, and factors affecting the pH of these waters reviewed. The cause of the low pH of surface waters of Sphagnum bogs (approximately pH 4) is critically investigated, and the relative importance of dissolved CO 2 and other inorganic acids, and organic acids to the low pH is assessed. Cation exchange on the surfaces of Sphagnum mosses is found to be a relatively unimportant acidification mechanism, but important to the chemical ecology of the plants. The redox chemistry of mire waters is described in terms of the geochemistry of such redox indicators as O 2, CO 2, CH 4, CO, H 2, H 2S, SO 42-, native Cu, and siderite (FeCO 3). Published studies of Eh in peatlands are cited, and the problems of Eh measurement and interpretation are explored. The chemical composition of mire waters (major and trace metals, and nonmetallic species) is examined, and factors affecting their composition reported. The abundance and distribution of mineral matter in peats is described, and the occurrence and formation of minerals of Fe (pyrite and other sulphides, siderite, vivianite), Cu (chalcopyrite, native Cu, covellite) and Zn (smithsonite and wurtzite) investigated. The abundance and distribution of major elements (Si, Al, Na, K, Mg, Ca) and trace metals (Ni, V, Cr, Fe, Mn, Cu, U, Zn, Pb) is described, and factors affecting their solubility examined.

Reconstructing historical atmospheric mercury deposition in Western Europe using: Misten peat bog cores, Belgium.

PubMed

Allan, Mohammed; Le Roux, Gael; Sonke, Jeroen E; Piotrowska, Natalia; Streel, Maurice; Fagel, Nathalie

2013-01-01

Four sediment cores were collected in 2008 from the Misten ombrotrophic peat bog in the Northern part of the Hautes Fagnes Plateau in Belgium. Total mercury (Hg) concentrations were analyzed to investigate the intra-site variability in atmospheric Hg deposition over the past 1,500 years. Mercury concentrations in the four cores ranged from 16 to 1,100 μg kg(-1), with the maxima between 840 and 1,100 μg kg(-1). A chronological framework was established using radiometric (210)Pb and (14)C dating of two cores (M1 and M4). Pollen horizons from these two cores were correlated with data from two additional cores, providing a consistent dating framework between all the sites. There was good agreement between atmospheric Hg accumulation rates in the four cores over time based on precise age dating and pollen chronosequences. The average Hg accumulation rate before the influence of human activities (from 500 to 1,300 AD) was 1.8 ± 1 μg m(-2)y(-1) (2SD). Maximum Hg accumulation rates ranged from 90 to 200 μg m(-2)y(-1) between 1930 and 1980 AD. During the European-North American Industrial Revolution, the mean Hg accumulation rate exceeded the pre-Industrial values by a factor of 63. Based on comparisons with historical records of anthropogenic activities in Europe and Belgium, the predominant regional anthropogenic sources of Hg during and after the Industrial Revolution were coal burning and smelter Hg emissions. Mercury accumulation rates and chronologies in the Misten cores were consistent with those reported for other European peat records. Copyright © 2012 Elsevier B.V. All rights reserved.

Biological Sources of Branched Glycerol Dialkyl Glycerol Tetraethers (brGDGTs) in Terrestrial Hot Springs: A Possible Link Between Nitrogen-cycling Bacteria and brGDGT Production

NASA Astrophysics Data System (ADS)

Wang, J. X.; Xie, W.; Boyd, E. S.; Hedlund, B. P.; Zhang, C.

2014-12-01

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are common in peat, soil, lakes, rivers and hot springs. To seek the potential biological sources of brGDGTs in geothermal environments, we investigated 65 hot springs in the Yellowstone National Park (USA) and Tengchong (China). Together with previously published data from hot springs in the Great Basin (USA) and Tibet (China), we found that the abundance of brGDGTs tended to peak in springs with pH > 8. This contrasts with previous observations indicating an abundance of brGDGTs in acidic soils and peat bogs, suggesting a different biological source and function for lipids in these environments. In support of this hypothesis, a comparison of Cyclization ratios of Branched Tetraethers (CBT) between hot springs and surrounding soils indicated that more brGDGTs with cyclopentane moieties were produced in alkaline hot springs than in nearby low-temperature soils. Since Acidobacteria (the likely source of brGDGTs in peat bog environments) tend to have low CBT ratios, these data suggest a different source for brGDGTs in hot spring environments. RDA and regression analysis integrating brGDGT compounds and nitrogen species indicate that Bacteria involved in the nitrogen biogeochemical cycle (ammonia oxidation and nitrite reduction) may be related to the production of brGDGTs in terrestrial hot springs. However, direct evidence showing the link between nitrogen-cycling bacteria and brGDGT production has yet to be demonstrated under laboratory conditions. Nevertheless, our study expands the possibility of brGDGT sources into bacterial communities in terrestrial geothermal systems where Acidobacteria are absent or only a minor component.

Multi-year net ecosystem carbon balance at a horticulture-extracted restored peatland

NASA Astrophysics Data System (ADS)

Nugent, Kelly; Strachan, Ian; Strack, Maria

2017-04-01

Restoration of previously extracted peatlands is essential to minimize the impact of drainage and peat removal. Best practices restoration methods have been developed that include ditch blocking, site leveling and reintroducing bog vegetation using the moss layer transfer technique. A long term goal of restoration is the return to a peat accumulating ecosystem. Bois-des-Bel is a cool-temperate bog, located in eastern Quebec, Canada, that was vacuum harvested until 1980 and restored in 1999. While several studies have used discrete (chamber) methods to determine the net carbon exchange from rewetted or restored peatlands, ours appears to be the first to have multiple complete years of net ecosystem carbon exchange from a restored northern peatland. An eddy covariance flux tower instrumented with a sonic anemometer and open-path CO2/H2O and CH4 analyzers was operated continuously over three years to produce a robust estimate of net carbon sequestration. Our initial results indicate that this restored peatland was a consistent moderate annual net sink for CO2, a moderate source of CH4 and had low losses of dissolved organic carbon compared to undisturbed northern latitude peatlands. Closed chambers combined with a fast response CO2/H2O/CH4 analyzer were used to investigate ecohydrological controls on net ecosystem exchange of CO2 (NEE) and CH4 flux from the restored fields and remnant ditches at the site. CH4 release was found to be an order of magnitude higher in the ditches compared to the fields, with non-vegetated ditch showing a greater range in flux compared to areas invaded by Typha latifolia. Bubble magnitude and count were highest in the non-vegetated ditch, followed by Typha plots and were undetectable in the restored fields. The latter may be partially attributed to the high cover of Eriophorum vaginatum in the restored fields, plants that have aerenchymous tissue, as well as a much deeper water table level. While the non-vegetated ditch areas were a steady small source of CO2, NEE in the Typha plots showed significantly greater CO2 uptake capacity relative to any other restored plant community. High productivity combined with reduced CH4 flux suggests that Typha may be playing a key role in reducing the overall impact of the remnant ditches on the net ecosystem carbon balance. A preliminary footprint analysis suggests that ecosystem-level CH4 flux is being primarily driven by release from hotspots while the majority of the tower source area is a very small source of methane.

Grass species influence on plant N uptake - Determination of atmospheric N deposition to a semi-natural peat bog site using a 15N labelling approach

NASA Astrophysics Data System (ADS)

Hurkuck, Miriam; Brümmer, Christian; Spott, Oliver; Flessa, Heinz; Kutsch, Werner L.

2014-05-01

Large areas of natural peat bogs in Northwestern Germany have been converted to arable land and were subjected to draining and peat cutting in the past. The few protected peatland areas remaining are affected by high nitrogen (N) deposition. Our study site - a moderately drained raised bog - is surrounded by highly fertilized agricultural land and livestock production. In this study, we used a 15N pool dilution technique called 'Integrated Total Nitrogen Input' (ITNI) to quantify annual deposition of atmospheric N into biomonitoring pots over a two-year period. Since it considers direct N uptake by plants, it was expected to result in higher N input than conventional methods for determination of N deposition (e.g. micrometeorological approaches, bulk N samplers). Using Lolium multiflorum and Eriophorum vaginatum as monitor plants and low, medium and high levels of fertilization, we aimed to simulate increasing N deposition to planted pots and to allocate airborne N after its uptake by the soil-plant system in aboveground biomass, roots and soil. Increasing N fertilization was positively correlated with biomass production of Eriophorum vaginatum, whereas atmospheric plant N uptake decreased and highest airborne N input of 899.8 ± 67.4 µg N d-1 pot-1 was found for low N fertilization. In contrast, Lolium multiflorum showed a clear dependency of N supply on plant N uptake and was highest (688.7 ± 41.4 µg N d-1 pot-1) for highly fertilized vegetation pots. Our results suggest that grass species respond differently to increasing N input. While crop grasses such as Lolium multiflorum take up N according to N availability, species adopted to nutrient-limited conditions like Eriophorum vaginatum show N saturation effects with increasing N supply. Total airborne N input ranged from about 24 to 66 kg N ha-1 yr-1 dependent on the used indicator plant and the amount of added fertilizer. Parallel determination of atmospheric N deposition using a micrometeorological approach complemented with bulk samplers was about 24 kg N ha-1 yr-1 during both years of experiments and was thus at the lower range of results obtained by the ITNI method. The low 15N recovery rate of about 50 % during some experiments indicated an underestimation of the applied ITNI approach, resulting in a maximum possible N uptake of twice as high as the determined N input. Most likely, the intensive agricultural land management of the surrounding areas leads to this high N deposition into the protected peatland area. As a result, increasing sensitivity of ombrotrophic vegetation with a subsequent change in plant species composition and a decline in bog-specific vegetation cannot be excluded.

Heterotrophic bacterium Pseudomonas saponiphila and sunlight as impact factors on organo-mineral colloids transformations in boreal humic waters

NASA Astrophysics Data System (ADS)

Oleinikova, Olga; Drozdova, Olga; Shirokova, Liudmila; Lapitskiy, Sergey; Bychkov, Andrew; Pokrovsky, Oleg

2017-04-01

Two of the main factors of carbon balance in high latitudes, known to govern the CO2 flux from the lakes and rivers to the atmosphere, are bacterial mineralization (respiration) of allochthonous dissolved organic matter (DOM) and photochemical degradation of DOM. Yet, in contrast to large numbers of experimental and field studies on these factors impact on the utilization of DOM of different origin, the fate of metals bound to colloids during bacterial processing of DOM and behavior of trace element (TE) during photodegradation of DOM remains poorly constrained. This is especially important in view of essentially organic and organo-mineral colloidal status of TE in most boreal waters. To answer this questions, a monoculture of Pseudomonas saponiphila from a boreal creek in NW Karelia (Russia) was separated and allowed to interact with boreal peat leachate in nutrient-free media. We quantified colloidal transformation of the peat leachate during 5-days activity of live bacteria using 3 kDa, 50 kDa Amicon® centrifugal filtration and 0.45 µm syringe filtration. The total net decrease of the concentration of Dissolved Organic Carbon (DOC) over 93 h of exposure was within 5% of the initial value for all fractions except low molecular weight one (< 3 kDa), which yielded a 16%-decrease due to long-term bio-uptake or coagulation. Elements most affected by bacterial presence were Al, Mn, (Ni), Cu, Ga, REEs, Y, U which exhibited essentially the adsorption at the cell surface over first hrs of reaction, and Fe, Ti, (Zr), and Nb showing short-term adsorption and long-term assimilation. Towards a better understanding of concentration, size fractionation and speciation change of TE in boreal waters subjected to solar radiation, we conducted on-site photo-degradation experiments in stream and bog water from pristine zone of Northern Karelia (Russian subarctic). After 5 days of exposure, the DOM in stream photodegraded in a much smaller degree than that in the bog water with 25 and 60% removal of initial DOC, respectively. Specific UV absorption (SUVA254) decreased by a factor of 1.75 and 5 over 200 h of exposure in stream and bog water, respectively. The removal of Fe and Al occurred only in the bog water (90 % and 50% respectively, over 5 days of reaction), whereas no detectable decrease of Al and Fe concentration (< 0.22 µm) was observed in the boreal stream. The majority of colloidal constituents including DOC, Fe, Al, metal micronutrients are weakly affected by heterotrophic bacterial activity and as such the stability of peat soil colloids in boreal waters is expected to be high. In contrast to this, in bog waters, alkali, alkaline-earth metals and divalent metal micornutrients, present in the form of organic complexes (50-80%), may be completely degraded over a week of sunlight exposure. We acknowledge support from a RFBR research projects №№ 16-55-150002 HЦHИ_a, 15-05-05000_a, 14-05-00430_a, 16-05-00542_a. Experimental study was supported by RSF № 14-50-00029.

Linking Microbial and Biogeochemical Studies: Biological Controls of Methane Release from an Acidic Natural Wetland in Central Pennsylvania

NASA Astrophysics Data System (ADS)

Biddle, J. F.; Turich, C.; Brantley, S.; Bruns, M.

2002-12-01

Wetlands produce between 55 and 150 Tg of methane per year, or ~70% of all natural methane, and 20% of total methane (natural and anthropogenic). Understanding inputs to the global methane cycle depends on integrated in situ study of the sources and sinks of methane, as well as the rate and magnitude of methane production and consumption. Bear Meadows Natural Area in central Pennsylvania (N 40° 43.796' W 077° 45.310; 554 m elevation) contains an acidic, methane-producing, peaty bog with vegetation that is typical of wetlands at higher latitudes. In this four year study conducted within a cross-disciplinary training course offered by the NSF-IGERT Biogeochemical Research Initiative in Education (BRIE) program at Penn State University, graduate students applied a combination of geochemical and microbiological techniques to explore microbial diversity and activity in Bear Meadows sediments. The methane flux at the peat:water interface was highly variable, from 0.01 to over 3000 umol/m2/min in both sphagnum and sedge vegetation. The methane released from the bog had a carbon isotopic composition of -60 %o, typical of biogenic methane. Analysis of peat pore waters showed that the most methane was produced 30 cm below the peat:water interface, with a broad peak of methane in pore waters from 20-40 cm. At 21 cm below the peat:water interface, profiles of Archaeal 16S-23S ribosomal RNA spacer regions revealed the presence of populations having 92% similarity to 16S rRNA sequences of Methanoculleus marisnigri. Phospholipid fatty acids (PLFA) and compound specific isotope analysis revealed other biological controls on the methane cycle. PLFAs typical of methanotrophic bacteria were also present within peat cores from 20-30 cm below the water interface. The depleted carbon isotopic composition of these biomarkers (C16:1 and C18:1 fatty acids) was - 31.4 %o and - 33.8%o, indicative of methane oxidation. The presence of biomarkers of methane oxidizing bacteria within the zone of methane production may indicate that there is temporal or spatial heterogeneity in oxygen concentration within the peat. This interdisciplinary approach helped define specific ecological niches where novel methanogens and methane oxidizers may be active in a typical northern wetland. Through BRIE, on-going studies of the Bear Meadows wetland will focus on detecting other potentially novel aerobic and anaerobic microbes, and determining the biological influence on methane release to the atmosphere.

Bringing back the rare - biogeochemical constraints of peat moss establishment in restored cut-over bogs

NASA Astrophysics Data System (ADS)

Raabe, Peter; Blodau, Christian; Hölzel, Norbert; Kleinebecker, Till; Knorr, Klaus-Holger

2016-04-01

In rewetted cut-over bogs in north-western Germany and elsewhere almost no spontaneous recolonization of hummock peat mosses, such as Sphagnum magellanicum, S. papillosum or S. rubellum can be observed. However, to reach goals of climate protection every restoration of formerly mined peatlands should aim to enable the re-establishment of these rare but functionally important plant species. Besides aspects of biodiversity, peatlands dominated by mosses can be expected to emit less methane compared to sites dominated by graminoids. To assess the hydrological and biogeochemical factors constraining the successful establishment of hummock Sphagnum mosses we conducted a field experiment by actively transferring hummock species into six existing restoration sites in the Vechtaer Moor, a large peatland complex with active peat harvesting and parallel restoration efforts. The mosses were transferred as intact sods in triplicate at the beginning of June 2016. Six weeks (mid-July) and 18 weeks later (beginning of October) pore water was sampled in two depths (5 and 20 cm) directly beneath the inoculated Sphagnum sods as well as in untreated control plots and analysed for phosphate, ferrous iron, ammonia, nitrate and total organic carbon (TOC). On the same occasions and additionally in December, the vitality of mosses was estimated. Furthermore, the increment of moss height between July and December was measured by using cranked wires and peat cores were taken for lab analyses of nutrients and major element inventories at the depths of pore water sampling. Preliminary results indicate that vitality of mosses during the period of summer water level draw down was strongly negatively related to plant available phosphate in deeper layers of the residual peat. Furthermore, increment of moss height was strongly negatively related to TOC in the upper pore waters sampled in October. Concentration of ferrous iron in deeper pore waters was in general significantly higher beneath Sphagnum sods compared to control plots suggesting a direct impact of hummock mosses on microsite soil moisture conditions. However, with an increase of water levels towards winter season accompanied by increase of ferrous iron and concurrent increase of phosphate in pore waters of the upper peat layers the vitality was strongly positively related to plant available phosphate. This suggests that actively transferred hummock mosses suffering temporarily from desiccation during the dry summer season are able to recover also under relatively higher trophic conditions as long as water level and redox state favour an optimal supply of required water nutrients.

Antimony in recent, ombrotrophic peat from Switzerland and Scotland: Comparison with natural background values (5,320 to 8,020 14C yr BP) and implications for the global atmospheric Sb cycle

NASA Astrophysics Data System (ADS)

Shotyk, William; Krachler, Michael; Chen, Bin

2004-03-01

The lowest concentrations, atmospheric fluxes, and enrichments of Sb in a Swiss bog were found in peat samples dating from 8,020 to 5,320 14C yr BP when Sb inputs were proportional to those of Sc and effectively controlled by deposition of soil dust. For comparison with these ancient samples, modern peat samples from five rural areas of Switzerland and two remote areas of Scotland and Shetland are highly contaminated with Sb, with enrichments of the order of 30 to 80 times. "Lithogenic" Sb concentrations calculated using the Sc concentrations and background Sb/Sc ratio are dwarfed at all sites by "anthropogenic" Sb. The chronology and intensity of the Sb enrichments are in many ways similar to those of Pb which indicates that (1) Sb, like Pb, is well preserved in ombrotrophic peat and (2) the extent of human impacts on the geochemical cycle of Sb is comparable to that of Pb. The similar distribution of Sb and Pb can be explained in terms of their chemical and mineralogical associations, with most lead minerals being rich in Sb. Assuming that the "background" Sb flux (0.35 μg/m2/yr) from the Swiss bog is representative of preanthropogenic deposition rates worldwide, the global flux of natural Sb is estimated at 154 T/a. Using the natural Pb flux published by [1987] of 2600 T/a and the "background" Pb/Sb ratio (29) of the preanthropogenic peat samples, the global flux of natural Sb is estimated at 90 T/a. Either way, these values (90 to 154 T/a) are considerably lower than the current estimate of natural Sb to the global atmosphere (2400 T/a) published by [2001]. Assuming that the current estimate of anthropogenic Sb to the global atmosphere (1600 T/a) is correct [, 2001], the ratio of anthropogenic to natural Sb emissions is on the order of 10 to 18. Taken together, the data from modern and ancient peat samples suggests that the impact of human activities on the global geochemical cycle of Sb may have been underestimated by an order of magnitude. Like Pb, Sb has no known biological function, has a similar toxicity, and is a cumulative poison. The environmental geochemistry of Sb therefore may have a relevance to human and environmental health comparable to that of Pb.

CO2 Emissions in an Oil Palm Plantation on Tropical Peat in Malaysia

NASA Astrophysics Data System (ADS)

Leclerc, M.; Zhang, G.; Jantan, N. M.; Harun, M. H.; Kamarudin, N.; Choo, Y. M.

2016-12-01

Tropical peats are large contributors to greenhouse gas emissions and differ markedly from their counterparts at temperate latitudes. The rapid deforestation and subsequent land conversion of tropical virgin forests in Southeast Asia have been decried by environmental groups worldwide even though there is currently little robust scientific evidence to ascertain the net amount of greenhouse gas released to the atmosphere. The conversion to oil palm plantation at a large scale further exacerbates the situation. This paper shows preliminary data on CO2 emissions in a converted oil palm plantation grown on tropical peat in northeast Malaysia.

Revealing spatial distribution of soil organic carbon contents and stocks of a disturbed bog relict by in-situ NIR and apparent EC mapping

NASA Astrophysics Data System (ADS)

Bechtold, Michel; Tiemeyer, Bärbel; Don, Axel; Altdorff, Daniel; van der Kruk, Jan; Huisman, Johan A.

2013-04-01

Previous studies showed that in-situ visible near-infrared (vis-NIR) spectroscopy can overcome the limitations of conventional soil sampling. Costs can be reduced and spatial resolution enhanced when mapping field-scale variability of soil organic carbon (SOC). Detailed maps can help to improve SOC management and lead to better estimates of field-scale total carbon stocks. Knowledge of SOC field patterns may also help to reveal processes and factors controlling SOC variability. In this study, we apply in situ vis-NIR and apparent electrical conductivity (ECa) mapping to a disturbed bog relict. The major question of this application study was how field-scale in-situ vis-NIR mapping performs for a very heterogeneous area and under difficult grassland conditions and under highly-variable water content conditions. Past intensive peat cutting and deep ploughing in some areas, in combination with a high background heterogeneity of the underlying mineral sediments, have led to a high variability of SOC content (5.6 to 41.3 %), peat layer thickness (25 to 60 cm) and peat degradation states (from nearly fresh to amorphous). Using a field system developed by Veris Technologies (Salina KS, USA), we continuously collected vis-NIR spectra at 10 cm depth (measurement range: 350 nm to 2200 nm) over an area of around 12 ha with a line spacing of about 12 m. The system includes a set of discs for measuring ECa of the first 30 and 90 cm of the soil. The same area was also mapped with a non-invasive electro-magnetic induction (EMI) setup that provided ECa data of the first 25, 50 and 100 cm. For calibration and validation of the spatial data, we took 30 representative soil samples and 15 soil cores of about 90 cm depth, for which peat thickness, water content, pore water EC, bulk density (BD), as well as C and N content were determined for various depths. Preliminary results of the calibration of the NIR spectra to the near-surface SOC contents indicate good data quality despite the challenging site conditions. Bore hole data indicates that the peat layer is characterized by lower BD, higher pore water EC, higher SOC content, and higher water contents compared to the underlying mineral sediments. This ECa contrast at the peat-sand interface is promising for using the various ECa investigation depths as predictors for peat thickness. Preliminary EMI results also show a correlation between ECa and SOC content, most strongly for the 25 cm EMI signal. We evaluate how vis-NIR and ECa data can be used in a joined approach to estimate SOC content as well as SOC stock distribution.

High potential of nitrogen fixation in pristine, ombrotrophic bogs in Southern Patagonia

NASA Astrophysics Data System (ADS)

Knorr, Klaus-Holger; Horn, Marcus A.; Bahamonde Aguilar, Nelson A.; Borken, Werner

2015-04-01

Nitrogen (N) input in pristine peatlands occurs via natural input of inorganic N through atmospheric deposition or biological dinitrogen (N2) fixation. However, N2 fixation is to date mostly attributed to bacteria and algae associated to Sphagnum and its contribution to plant productivity and peat buildup has been often underestimated in previous studies. Based on net N storage, exceptionally low N deposition, and high abundance of vascular plants at pristine peatlands in Southern Patagonia, we hypothesized that there must be a high potential of non-symbiotic N2 fixation not limited to the occurrence of Sphagnum. To this end, we chose two ombrotrophic bogs with spots that are dominated either by Sphagnum or by vascular, cushion-forming plants and sampled peat from different depths for incubation with 15N2 to determine N2 fixation potentials. Moreover, we analyzed 15N2 fixation by a nodule-forming, endemic conifer inhabiting the peatlands. Results from 15N2 uptake were compared to the conventional approach to study N2 fixation by the acetylene reduction assay (ARA). Using 15N2 as a tracer, high non-symbiotic N2 fixation rates of 0.3-1.4 μmol N g-1 d-1 were found down to 50 cm under micro-oxic conditions (2 vol.%) in samples from both plots either covered by Sphagnum magellanicum or by vascular cushion plants. Peat N concentrations suggested a higher potential of non-symbiotic N2 fixation under cushion plants, likely because of the availability of easily decomposable organic compounds as substrates and oxic conditions in the rhizosphere. In the Sphagnum plots, high N2 fixation below 10 cm depth would rather reflect a potential fixation that may switch on during periods of low water levels when oxygen penetrates deeper into the peat. 15N natural abundance of live Sphagnum from 0-10 cm pointed to N uptake solely from atmospheric deposition and non-symbiotic N2 fixation. 15N signatures of peat from the cushion plant plots indicated additional N supply from N mineralization. Nitrogen fixation by the conifer Lepidothamnus fonkii was exceptionally high, reaching 3.1 μmol N g-1 d.w. d-1 detected in roots, stems, and green biomass. For L. fonkii, we could identify a specific association with Beijerinckiaceae as N2 fixing bacteria in the root nodules, whereas the rhizosphere peat was dominated by other diazotrophs. The ARA considerably underestimated N2 fixation and can thus not be recommended for peatland studies. Our findings suggest that non-symbiotic or associative N2 fixation overcomes N deficiency in different vegetation communities and has great significance for N cycling and peat accumulation in pristine peatlands.

Climatic Drivers for Multi-Decadal Shifts in Solute Transport and Methane Production Zones within a Large Peat Basin

NASA Technical Reports Server (NTRS)

Glaser, Paul H.; Siegel, Donald I.; Chanton, Jeffrey P.; Reeve, Andrew S.; Rosenberry, Donald O.; Corbett, J. Elizabeth; Dasgupta, Soumitri; Levy, Zeno

2016-01-01

Northern peatlands are an important source for greenhouse gases but their capacity to produce methane remains uncertain under changing climatic conditions. We therefore analyzed a 43-year time series of pore-water chemistry to determine if long-term shifts in precipitation altered the vertical transport of solutes within a large peat basin in northern Minnesota. These data suggest that rates of methane production can be finely tuned to multi-decadal shifts in precipitation that drive the vertical penetration of labile carbon substrates within the Glacial Lake Agassiz Peatlands. Tritium and cation profiles demonstrate that only the upper meter of these peat deposits was flushed by downwardly moving recharge from 1965 through 1983 during a Transitional Dry-to-Moist Period. However, a shift to a moister climate after 1984 drove surface waters much deeper, largely flushing the pore waters of all bogs and fens to depths of 2 m. Labile carbon compounds were transported downward from the rhizosphere to the basal peat at this time producing a substantial enrichment of methane in Delta C-14 with respect to the solid-phase peat from 1991 to 2008. These data indicate that labile carbon substrates can fuel deep production zones of methanogenesis that more than doubled in thickness across this large peat basin after 1984. Moreover, the entire peat profile apparently has the capacity to produce methane from labile carbon substrates depending on climate-driven modes of solute transport. Future changes in precipitation may therefore play a central role in determining the source strength of peatlands in the global methane cycle.

Climatic drivers for multidecadal shifts in solute transport and methane production zones within a large peat basin

USGS Publications Warehouse

Glaser, Paul H.; Siegel, Donald I.; Chanton, Jeffrey P.; Reeve, Andrew S.; Rosenberry, Donald O.; Corbett, J. Elizabeth; Dasgupta, Soumitri; Levy, Zeno

2016-01-01

Northern peatlands are an important source for greenhouse gases, but their capacity to produce methane remains uncertain under changing climatic conditions. We therefore analyzed a 43 year time series of the pore-water chemistry to determine if long-term shifts in precipitation altered the vertical transport of solutes within a large peat basin in northern Minnesota. These data suggest that rates of methane production can be finely tuned to multidecadal shifts in precipitation that drive the vertical penetration of labile carbon substrates within the Glacial Lake Agassiz Peatlands. Tritium and cation profiles demonstrate that only the upper meter of these peat deposits was flushed by downwardly moving recharge from 1965 to 1983 during a Transitional Dry-to-Moist Period. However, a shift to a moister climate after 1984 drove surface waters much deeper, largely flushing the pore waters of all bogs and fens to depths of 2 m. Labile carbon compounds were transported downward from the rhizosphere to the basal peat at this time producing a substantial enrichment of methane in Δ14C with respect to the solid-phase peat from 1991 to 2008. These data indicate that labile carbon substrates can fuel deep production zones of methanogenesis that more than doubled in thickness across this large peat basin after 1984. Moreover, the entire peat profile apparently has the capacity to produce methane from labile carbon substrates depending on climate-driven modes of solute transport. Future changes in precipitation may therefore play a central role in determining the source strength of peatlands in the global methane cycle.

The initiation and development of small peat-forming ecosystems adjacent to lakes in the north central Canadian low arctic during the Holocene

NASA Astrophysics Data System (ADS)

Camill, Philip; Umbanhowar, Charles E.; Geiss, Christoph; Edlund, Mark B.; Hobbs, Will O.; Dupont, Allison; Doyle-Capitman, Catherine; Ramos, Matthew

2017-07-01

Small peat-forming ecosystems in arctic landscapes may play a significant role in the regional biogeochemistry of high-latitude systems, yet they are understudied compared to arctic uplands and other major peat-forming regions of the North. We present a new data set of 25 radiocarbon-dated permafrost peat cores sampled around eight low arctic lake sites in northern Manitoba (Canada) to examine the timing of peat initiation and controls on peat accumulation throughout the Holocene. We used macrofossils and charcoal to characterize changes in the plant community and fire, and we explored potential impacts of these local factors, as well as regional climatic change, on rates of C accumulation and C stocks. Peat initiation was variable across and within sites, suggesting the influence of local topography, but 56% of the cores initiated after 3000 B.P. Most cores initiated and remained as drier bog hummock communities, with few vegetation transitions in this landscape. C accumulation was relatively slow and did not appear to be correlated with Holocene-scale climatic variability, but C stocks in this landscape were substantial (mean = 45.4 kg C m-2), potentially accounting for 13.2 Pg C in the Taiga Shield ecozone. To the extent that small peat-forming systems are underrepresented in peatland mapping, soil organic carbon (SOC) stocks may be underestimated in arctic regions. Mean fire severity appeared to be negatively correlated with C accumulation rates. Initiation and accumulation of soil C may respond to both regional and local factors, and substantial lowland soil C stocks have the potential for biogeochemical impacts on adjacent aquatic ecosystems.

Elucidating effects of atmospheric deposition and peat decomposition processes on mercury accumulation rates in a northern Minnesota peatland over last 10,000 cal years

NASA Astrophysics Data System (ADS)

Nater, E. A.; Furman, O.; Toner, B. M.; Sebestyen, S. D.; Tfaily, M. M.; Chanton, J.; Fissore, C.; McFarlane, K. J.; Hanson, P. J.; Iversen, C. M.; Kolka, R. K.

2014-12-01

Climate change has the potential to affect mercury (Hg), sulfur (S) and carbon (C) stores and cycling in northern peatland ecosystems (NPEs). SPRUCE (Spruce and Peatland Responses Under Climate and Environmental change) is an interdisciplinary study of the effects of elevated temperature and CO2 enrichment on NPEs. Peat cores (0-3.0 m) were collected from 16 large plots located on the S1 peatland (an ombrotrophic bog treed with Picea mariana and Larix laricina) in August, 2012 for baseline characterization before the experiment begins. Peat samples were analyzed at depth increments for total Hg, bulk density, humification indices, and elemental composition. Net Hg accumulation rates over the last 10,000 years were derived from Hg concentrations and peat accumulation rates based on peat depth chronology established using 14C and 13C dating of peat cores. Historic Hg deposition rates are being modeled from pre-industrial deposition rates in S1 scaled by regional lake sediment records. Effects of peatland processes and factors (hydrology, decomposition, redox chemistry, vegetative changes, microtopography) on the biogeochemistry of Hg, S, and other elements are being assessed by comparing observed elemental depth profiles with accumulation profiles predicted solely from atmospheric deposition. We are using principal component analyses and cluster analyses to elucidate relationships between humification indices, peat physical properties, and inorganic and organic geochemistry data to interpret the main processes controlling net Hg accumulation and elemental concentrations in surface and subsurface peat layers. These findings are critical to predicting how climate change will affect future accumulation of Hg as well as existing Hg stores in NPE, and for providing reference baselines for SPRUCE future investigations.

Response of surface CH4 and CO2 fluxes to whole ecosystem warming and elevated CO2 in a boreal black spruce peatland, northern Minnesota

NASA Astrophysics Data System (ADS)

Hsieh, I. F.; Gill, A. L.; Finzi, A.

2017-12-01

Potential increase in peatland C losses by environmental change has been presented by impacting the balance of CO2 and CH4 sequestration and release. While temperature warming may accelerate the temperature-sensitive processes and release CO2 and CH4 from peat C stores, factors associated with warming and that associated with elevated CO2 concentration may alter the intrinsic characteristics of CO2 and CH4 emission from peatland. By leveraging Spruce and Peatland Responses Under Changing Environments (SPRUCE) experiment, we measured peat surface CO2 and CH4 fluxes and their i13C signatures across a gradient of warming temperatures in a boreal black spruce peat bog in 2015 and 2016 growing seasons. Elevated CO2 (eCO2) treatment was added to the warming experiment in June, 2016. Our results show both CH4 and CO2 flux increased with warming temperature in the two-year measurement period. Total emission for both gases were higher in 2016 with whole ecosystem warming than that in 2015 with deep peat heat warming. The 2016 increase in CO2 emission was significantly larger in the hummock microtopographic position compared to hollows. The opposite was true for CH4 fluxes, where the increase was strongest in the hollows. In fact, CH4 flux from hummocks declined in 2016 compared to 2015, suggesting lower overall rates of CH4 production and/or greater rates of methanotrophy. The increase (less depleted) in i13C -CH4 signatures suggest acetoclastic methanogensis increased its contribution to total CH4 production across the growing season and in response to experimental warming, while hydrogenotrophic methanogenesis dominated total CH4 production. On the contrary, results of i13C-CO2 show no significant change in the contribution of different sources to total CO2 emission through time or across warming temperature. On the other hand, i13C-CO2 signatures under CO2 fumigation in 2016 was significantly depleted since the eCO2 initiation, indicating a rapid increase in plant productivity and the subsequent belowground transfer of photosynthate. Our results emphasize the susceptibleness of northern peat bog to changes in the environment by illustrating measureable influences of whole ecosystem warming and elevated CO2 on greenhouse gases emission.

Holocene monsoon variability inferred from Targo Xian peat bog in the Tangra Yumco basin, central Tibetan Plateau

NASA Astrophysics Data System (ADS)

Henkel, Karoline; Haberzettl, Torsten; Miehe, Sabine; Frenzel, Peter; Daut, Gerhard; Dietze, Elisabeth; Kasper, Thomas; Ahlborn, Marieke; Mäusbacher, Roland

2013-04-01

The Tibetan Plateau is the greatest plateau on Earth with an average altitude of 4,500 m asl. Due to its high elevation, large area and significant role in the formation of the Asian Monsoon Systems (e.g., Indian Ocean and East-Asian Summer Monsoon) it is considered to react very sensitive to climate variations. The numerous lake systems on the Tibetan Plateau represent excellent archives reflecting variations in the strength of the monsoon system in terms of hydrological changes expressed in lake level fluctuations. For example, terraces and lacustrine deposits around the saline lake Tangra Yumco indicate lake level highstands up to ~215 m higher than the present lake level. To study Holocene lake level variations we investigated a 3.6 m long sediment core recovered from a peat bog (near the Targo Xian settlement, 30°46'N, 86°40'E) on a recessional lake level terrace ~150 m above the present shoreline of Tangra Yumco. In particular, our analyses of sedimentological (grain size), geochemical (CNS and ICP-OES) and mineralogical (XRD) data allow a detailed and high-resolution interpretation of the hydrological conditions during the Holocene. The existence of two carbonate layers in the Targo Xian record, separated by a sand layer and intercalated in peat sequences at the bottom and top of the core, provide evidence for two stable lake stages at the coring position. Peat at the bottom of the core, which is radiocarbon-dated to 11,130 +130/-345 cal BP, indicates wetland conditions similar to the Recent situation (Miehe et al., submitted). After a transition zone, a layer of pure aragonitic lake marl gives evidence for a lake stage. During this stage, high values of the total inorganic carbon (TIC) and Ca/Ti ratios as well as low C/N ratios point to a stable lake due to wet climatic conditions. This carbonate layer can be correlated with a 2-3 m thick carbonate layer found in outcrops around the present lake Tangra Yumco presenting a high lake level until approx. 2.3 (+/-0.2) ka BP (OSL age, Long et al. 2012). Results of former investigations of other lakes on the Tibetan Plateau (e.g., lake Nam Co (Kasper et al., 2012)) point to a strong Indian Ocean Summer Monsoon during the Early to Mid Holocene. In the presented record, a falling lake level and a possible desiccation of the coring location is shown by a coarse sand layer including gravel. Another lake marl section above is well delimited from the other sections in its mineralogical composition as it is composed by calcite reflecting an additional lake stage at the coring site. This led to the assumption, that this second lake stage was characterized by a smaller lake with a higher detrital input which existed until approx. 930 +45/-135 cal BP. After an oscillation of dry and wet (peat production) phases a constant peat bog developed and is still present. References: Kasper, T. et al. (2012): doi: 10.1016/j.quascirev.2012.02.011 Long, H. et al. (2012): doi: 10.1016/j.quageo.2011.11.005 Miehe et al. (submitted): JOPL

Influence of the kind of peat and the depth of sampling on the biochemical properties of Tagan peatland

NASA Astrophysics Data System (ADS)

Wojciech Szajdak, Lech; Inisheva, Lydia I.

2010-05-01

The upper layer of a peat bog in which organic matter decomposes aerobically much more rapidly than in the underlying, anaerobic catotelm. As litter accumulates at the surface the size of the catotelm increases, because the thickness of the acrotelm is limited to depth at which aerobic respiration can occur. Although the rate of decomposition per unit volume of material is much greater in the acrotelm than in the catotelm, a point is reached at which the difference in volume between the two layers is such that the total rate of decomposition in the catotelm is equal to that in the acrotelm. This limits the thickness to which the bog can grow. Should there be a climate change (e.g. an increase in precipitation) growth can resume. Bogs therefore preserve a record of climatic conditions. Soils samples were taken from four places marked as No 1, 2, 3 and 4 each from two depth 0-25 and 50-75 cm of the peatland Tagan. Peatlands Tagan is located near Tomsk, West Siberia, Russia. Place No 1 in both layers represents grasses peat with the degree of the decomposition ranged from 25 to 35% (pH 6.31-7.95). Point 2 is characterized by wooden and wooden grasses peat with 35% degree of the decomposition (pH 5.16-9.31. There is buckbean peat in the points 3 and 4 (pH 6.4-6.49). However, 1.5 m depth of sapropel is located in point 4. The activity of the following enzymes: xanthine oxidase, phenolic oxidase, peroxidase, urease, nitrate reductase were measured and two forms of organic carbon (total organic carbon and dissolved organic carbon) and two form of iron Fe(II) and Fe(III) were determined in these samples. These enzymes participate in several biochemical pathways in soil connected with redox potential. The concentrations of indole-3-acetic acid, very famous fitohormone were also measured. It was observed in all places of sampling significant increase of the total organic carbon with an increase of the depth. However, the quantity of dissolved organic carbon closely decreased with an increase of the depth, suggesting lower microbiological activity of this level. The increase of the ratios Fe(II)/Fe(III) for place 1 and 2 and 4 and both depth 0-25 were similar (0.56; 0.59 and 0.65) indicating similar redox properties of these levels. Higher contents of F(III) were determined in upper layer than in lower layer of all samples. It indicate higher oxidizing properties upper layer than lower one The activity of nitrate reductase, peroxidase, phenolic axidase and xanthine oxidase agree with the content of two forms of iron in samples from all depth. In all samples was observed the decrease of the activity of urease with an increase of the depth. It suggest higher rate of the degradation process of urea created from the decomposition of peptides in peat. In sample No 1 the concentrations of indole-3-acetic acid very famous phytohormone were similar in both determined levels. However for sample No 2, 3 and 4 the significant decrease of the concentrations of indole-3-acetic acid with and increase of the depth of sampling was observed. Acknowledgements: This work was supported by a grant No. N N305 3204 36 founded by Polish Ministry of Education and by RFFR (No.No. 09-05-00235, 09-05-00395), Minister of Education and Science (No. 02.740.11.0325).

Changes in vegetation, peat properties and peat accumulation in Swedish peatlands as revealed by archive data.

NASA Astrophysics Data System (ADS)

Schoning, Kristian; Sohlenius, Gustav

2016-04-01

In this investigation we have studied patterns in peat accumulation and changes in mire status since the early 1900s for two areas in Sweden. In the early 1900s the Geological Survey of Sweden collected a vast amount of peat and peatland data, including information on vegetation and land-use. We have used this archive data to evaluate changes in mire vegetation, mire wetness and surface peat properties, rates of peat accumulation, succession in young wetlands and the effects of cultivation on peatlands. In total 156 mires in an uplift area of eastern middle Sweden were included in the data-set, including both pristine mires and peatlands used for agricultural purposes. In this area new peatlands have continuously been formed during the past 7 000 years making it possible to evaluate changes in peat accumulation over time. The other study area is situated in the south Swedish Uplands where we have revisited some larger bogs. The results from our investigation show that many of the peatlands have underwent major changes since the early 1900s. In most of the small peatlands we have found important changes in vegetation where mire vegetation has been replaced by nutrient demanding and/or dry species flora while the tree stand on large mires in south Sweden have increased. In some mires humification has increased in the uppermost peat-layers and the mire surface have become drier compared to the early 1900s. In eastern middle Sweden there are indications that the peat accumulation is lower 0,5 mm/year in older peatlands compared with younger ones 1,2 mm/year, although the mire vegetation in the older peatlands is dominated by sphagnum. The peat depth of the cultivated mires in this area shows a mean decrease of 40 cm since the early 1900s.

Methane emission from Minnesota peatlands: Spatial and seasonal variability

NASA Astrophysics Data System (ADS)

Dise, Nancy. B.

1993-03-01

The variability of methane flux with season, year, and habitat type was investigated in northern Minnesota peatlands from September 1988 through September 1990. Average daily fluxes calculated by integration of annual data for an open poor fen, an open bog, a forested bog hollow, a fen lagg in the forested bog and a forested bog hummock were 180,118, 38, 35, and 10 mg CH4 m-2 d-1, respectively. Fluxes among the five ecosystems were significantly different from one another, although emission from all sites was highest in July and lowest in March. Winter fluxes occurred in all sites but the fen lagg. There was no difference in fluxes measured from the same sites in the spring of 1986, 1989, or 1990, but summer fluxes were significantly higher in the wetter year of 1989 than in 1990, and a summer pulse in methane emission occurred in 1989 that was not seen the next year. Concentrations of methane in pore water, reflecting the seasonal balance of production, oxidation, and release, declined during the month of peak flux, then increased to levels of about 500 μM in December. Consistent spatial and temporal differences in flux could be ascribed to differences in water table, temperature, and peat nutrient status, although additional variability remained. Integration gave an annual average flux of 20 g CH4, m-2 ot; for the three bog ecosystems and 39 g CH4, m-2 for the two fen ecosystems. This gives an estimate of 1-2 Tg CH4, yr-1 from peatlands in the Great Lake states of Minnesota, Wisconsin, and Michigan.

Geomorphology and landscape organization of a northern peatland complex

NASA Astrophysics Data System (ADS)

Richardson, M. C.

2012-12-01

The geomorphic evolution of northern peatlands is governed by complex ecohydrological feedback mechanisms and associated hydro-climatic drivers. For example, prevailing models of bog development (i.e. Ingram's groundwater mounding hypothesis and variants) attempt to explicitly link bog dome characteristics to the regional climate based on analytical and numerical models of lateral groundwater flow and the first-order control of water table position on rates of peat accumulation. In this talk I will present new results from quantitative geomorphic analyses of a northern peatland complex at the De Beers Victor diamond mine site in the Hudson Bay Lowlands of northern Ontario. This work capitalizes on spatially-extensive, high-resolution topographic (LiDAR) data to rigorously test analytical and numerical models of bog dome development in this landscape. The analysis and discussion are then expanded beyond individual bog formations to more broadly consider ecohydrological drivers of landscape organization, with implications for understanding and modeling catchment-scale runoff response. Results show that in this landscape, drainage patterns exhibit relatively well-organized characteristics consistent with observed runoff responses in six gauged research catchments. Interpreted together, the results of these geomorphic and hydrologic analyses help refine our understanding of water balance partitioning among different landcover types within northern peatland complexes. These findings can be used to help guide the development of appropriate numerical model structures for hydrologic prediction in ungauged peatland basins of northern Canada.

An Antarctic hypotrichous ciliate, Parasterkiella thompsoni (Foissner) nov. gen., nov. comb., recorded in Argentinean peat-bogs: morphology, morphogenesis, and molecular phylogeny.

PubMed

Küppers, Gabriela Cristina; Paiva, Thiago da Silva; Borges, Bárbara do Nascimento; Harada, Maria Lúcia; Garraza, Gabriela González; Mataloni, Gabriela

2011-05-01

The ciliate Parasterkiella thompsoni (Foissner, 1996) nov. gen., nov. comb. was originally described from Antarctica. In the present study, we report the morphology, morphogenesis during cell division, and molecular phylogeny inferred from the 18S-rDNA sequence of a population isolated from the Rancho Hambre peat bog, Tierra del Fuego Province (Argentina). The study is based on live and protargol-impregnated specimens. Molecular phylogeny was inferred from trees constructed by means of the maximum parsimony, neighbor joining, and Bayesian analyses. The interphase morphology matches the original description of the species. During the cell division, stomatogenesis begins with the de novo proliferation of two fields of basal bodies, each one left of the postoral ventral cirri and of transverse cirri, which later unify. Primordia IV-VI of the proter develop from disaggregation of cirrus IV/3, while primordium IV of the opisthe develops from cirrus IV/2 and primordia V and VI from cirrus V/4. Dorsal morphogenesis occurs in the Urosomoida pattern-that is, the fragmentation of kinety 3 is lacking. Three macronuclear nodules are generated before cytokinesis. Phylogenetic analyses consistently placed P. thompsoni within the stylonychines. New data on the morphogenesis of the dorsal ciliature justifies the transference of Sterkiella thompsoni to a new genus Parasterkiella. Copyright © 2011 Elsevier GmbH. All rights reserved.

Final Report for Wetlands as a Source of Atmospheric Methane: A Multiscale and Multidisciplinary Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

McFarlane, Karis J.

Boreal peatlands contain large amounts of old carbon, protected by anaerobic and cold conditions. Climate change could result in favorable conditions for the microbial decomposition and release of this old peat carbon as CO2 or CH4 back into the atmosphere. Our goal was to test the potential for this positive biological feedback to climate change at SPRUCE (Spruce and Peatland Response Under Climatic and Environmental Change), a manipulation experiment funded by DOE and occurring in a forested bog in Minnesota. Taking advantage of LLNL’s capabilities and expertise in chemical and isotopic signatures we found that carbon emissions from peat weremore » dominated by recently fixed photosynthates, even after short-term experimental warming. We also found that subsurface hydrologic transport was surprisingly rapid at SPRUCE, supplying microbes with young dissolved organic carbon (DOC). We also identified which microbes oxidize CH4 to CO2 at SPRUCE and found that the most active of these also fix N2 (which means they can utilize atmospheric N, making it accessible for other microbes and plants). These results reflect important interactions between hydrology, carbon cycling, and nitrogen cycling present at the bog and relevant to interpreting experimental results and modeling the wetland response to experimental treatments. LLNL involvement at SPRUCE continues through collaborations and a small contract with ORNL, the lead lab for the SPRUCE experiment.« less

Telmatocola sphagniphila gen. nov., sp. nov., a novel dendriform planctomycete from northern wetlands.

PubMed

Kulichevskaya, Irina S; Serkebaeva, Yulia M; Kim, Yongkyu; Rijpstra, W Irene C; Damsté, Jaap S Sinninghe; Liesack, Werner; Dedysh, Svetlana N

2012-01-01

Members of the phylum Planctomycetes are common inhabitants of northern wetlands. We used barcoded pyrosequencing to survey bacterial diversity in an acidic (pH 4.0) Sphagnum peat sampled from the peat bog Obukhovskoye, European North Russia. A total of 21189 bacterial 16S rRNA gene sequences were obtained, of which 1081 reads (5.1%) belonged to the Planctomycetes. Two-thirds of these sequences affiliated with planctomycete groups for which characterized representatives have not yet been available. Here, we describe two organisms from one of these previously uncultivated planctomycete groups. One isolate, strain OB3, was obtained from the peat sample used in our molecular study, while another strain, SP2(T) (=DSM 23888(T) = VKM B-2710(T)), was isolated from the peat bog Staroselsky moss. Both isolates are represented by aerobic, budding, pink-pigmented, non-motile, spherical cells that are arranged in unusual, dendriform-like structures during growth on solid media. These bacteria are moderately acidophilic and mesophilic, capable of growth at pH 4.0-7.0 (optimum pH 5.0-5.5) and at 6-30°C (optimum 20-26°C). The preferred growth substrates are various heteropolysaccharides and sugars, the latter being utilized only if provided in low concentrations (≤0.025%). In contrast to other described planctomycetes, strains SP2(T) and OB3 possess weak cellulolytic potential. The major fatty acids are C16:1ω5c, C18:1ω5c, C16:0, and C18:0. Characteristic lipids are the n-C31 polyunsaturated alkene (9-10 double bonds) and C30:1/C32:1 (ω-1) hydroxy fatty acids. The G + C content of the DNA is 58.5-59.0 mol%. Strains SP2(T) and OB3 share identical 16S rRNA gene sequences, which exhibit only 86 and 87% similarity to those of Gemmata obscuriglobus and Zavarzinella formosa. Based on the characteristics reported here, we propose to classify these novel planctomycetes as representatives of a novel genus and species, Telmatocola sphagniphila gen. nov., sp. nov.

Telmatocola sphagniphila gen. nov., sp. nov., a Novel Dendriform Planctomycete from Northern Wetlands

PubMed Central

Kulichevskaya, Irina S.; Serkebaeva, Yulia M.; Kim, Yongkyu; Rijpstra, W. Irene C.; Damsté, Jaap S. Sinninghe; Liesack, Werner; Dedysh, Svetlana N.

2012-01-01

Members of the phylum Planctomycetes are common inhabitants of northern wetlands. We used barcoded pyrosequencing to survey bacterial diversity in an acidic (pH 4.0) Sphagnum peat sampled from the peat bog Obukhovskoye, European North Russia. A total of 21189 bacterial 16S rRNA gene sequences were obtained, of which 1081 reads (5.1%) belonged to the Planctomycetes. Two-thirds of these sequences affiliated with planctomycete groups for which characterized representatives have not yet been available. Here, we describe two organisms from one of these previously uncultivated planctomycete groups. One isolate, strain OB3, was obtained from the peat sample used in our molecular study, while another strain, SP2T (=DSM 23888T = VKM B-2710T), was isolated from the peat bog Staroselsky moss. Both isolates are represented by aerobic, budding, pink-pigmented, non-motile, spherical cells that are arranged in unusual, dendriform-like structures during growth on solid media. These bacteria are moderately acidophilic and mesophilic, capable of growth at pH 4.0–7.0 (optimum pH 5.0–5.5) and at 6–30°C (optimum 20–26°C). The preferred growth substrates are various heteropolysaccharides and sugars, the latter being utilized only if provided in low concentrations (≤0.025%). In contrast to other described planctomycetes, strains SP2T and OB3 possess weak cellulolytic potential. The major fatty acids are C16:1ω5c, C18:1ω5c, C16:0, and C18:0. Characteristic lipids are the n-C31 polyunsaturated alkene (9–10 double bonds) and C30:1/C32:1 (ω-1) hydroxy fatty acids. The G + C content of the DNA is 58.5–59.0 mol%. Strains SP2T and OB3 share identical 16S rRNA gene sequences, which exhibit only 86 and 87% similarity to those of Gemmata obscuriglobus and Zavarzinella formosa. Based on the characteristics reported here, we propose to classify these novel planctomycetes as representatives of a novel genus and species, Telmatocola sphagniphila gen. nov., sp. nov. PMID:22529844

Investigating variability of biogenic gas dynamics in peat soils using high temporal frequency hydrogeophysical methods

NASA Astrophysics Data System (ADS)

Wright, William J.

Peat soils are known to be a significant source of atmospheric greenhouse gasses. However, the releases of methane and carbon dioxide gasses from peat soils are currently not well understood, particularly since the timing of the releases are poorly constrained. Furthermore, most research work performed on peatlands has been focused on temperate to sub-arctic peatlands, while recent works have suggested that gas production rates from low-latitude peat soils are higher than those from colder climates. The purpose of the work proposed here is to introduce an autonomous Ground Penetrating Radar (GPR) method for investigating the timing of gas releases from peat soils at the lab scale utilizing samples originating from Maine and the Florida Everglades, and at the field scale in a Maine peatland. Geophysical data are supported by direct gas flux measurements using the flux chamber method enhanced by timelapse photography, and terrestrial LiDAR (TLS) monitoring surface deformation.

Biophysical drivers of seasonal variability in Sphagnum gross primary production in a northern temperate bog

Treesearch

Anthony P. Walker; Kelsey R. Carter; Lianhong Gu; Paul J. Hanson; Avni Malhotra; Richard J. Norby; Stephen D. Sebestyen; Stan D. Wullschleger; David J. Weston

2017-01-01

Sphagnum mosses are the keystone species of peatland ecosystems. With rapid rates of climate change occurring in high latitudes, vast reservoirs of carbon accumulated over millennia in peatland ecosystems are potentially vulnerable to rising temperature and changing precipitation. We investigate the seasonal drivers of Sphagnum...

Investigating carbon dynamics in Siberian peat bogs using molecular-level analyses

NASA Astrophysics Data System (ADS)

Kaiser, K.; Benner, R. H.

2013-12-01

Total hydrolysable carbohydrates, and lignin and cutin acid compounds were analyzed in peat cores collected 56.8 N (SIB04), 58.4 N (SIB06), 63.8 N (G137) and 66.5 N (E113) in the Western Siberian Lowland to investigate vegetation, chemical compositions and the stage of decomposition. Sphagnum mosses dominated peatland vegetation in all four cores. High-resolution molecular analyses revealed rapid vegetation changes on timescales of 50-200 years in the southern cores Sib4 and Sib6. Syringyl and vanillyl (S/V) ratios and cutin acids indicated these vegetation changes were due to varying inputs of angiosperm and gymnosperm and root material. In the G137 and E113 cores lichens briefly replaced sphagnum mosses and vascular plants. Molecular decomposition indicators used in this study tracked the decomposition of different organic constituents of peat organic matter. The carbohydrate decomposition index was sensitive to the polysaccharide component of all peat-forming plants, whereas acid/aldehyde ratios of S and V phenols (Ac/AlS,V) followed the lignin component of vascular plants. Low carbohydrate decomposition indices in peat layers corresponded well with elevated (Ad/Al)S,V ratios. This suggested both classes of biochemicals were simultaneously decomposed, and decomposition processes were associated with extensive total mass loss in these ombrotrophic systems. Selective decomposition or transformation of lignin was observed in the permafrost-influenced northern cores G137 and E113. Both cores exhibited the highest (Ad/Al)S,V ratios, almost four-fold higher than measured in peat-forming plants. The extent of decomposition in the four peat cores did not uniformly increase with age, but showed episodic extensive decomposition events. Variable decomposition events independent of climatic conditions and vegetation shifts highlight the complexity of peatland dynamics.

Effect of Organic Material on Mechanical, Hydrological, and Microstructural Properties of Mudstones

NASA Astrophysics Data System (ADS)

Altobelli, M. A.; Reece, J. S.

2016-12-01

In this research we analyze the influence of organic material on the mechanical and flow properties of mudstones. We uniformly mix peat, milled and harvested by Bord na Móna from the surface of bogs in Ireland, with natural mudstone from Site C0011 in the Nankai Trough, offshore Japan, obtained during Integrated Ocean Drilling Program Expedition 322. The mudstone had previously been disaggregated into a homogeneous dry powder of clay- and silt-sized particles. The peat is ground and dry-sieved to achieve a similar particle size distribution as the mudstone (< 63 micrometers). In order to understand the mechanical and hydrological processes affected by peat, we prepare dry peat-mudstone mixtures with three different peat concentrations: 0 wt%, 5 wt%, and 10 wt%. Then, these peat - mudstone mixtures are saturated with deionized water at a water content of 109%, formed into stable slurries, and uniaxially compressed to an axial stress of 100 kPa using resedimentation, a method that simulates the natural behavior of deposition and burial in the laboratory under controlled conditions. How the organic material interacts with the mudstone matrix and pore fluid under compression influences the physical properties of the mudstones such as porosity, compressibility, and permeability; all of which are measured in the resedimentation experiments. We will also analyze the microstructural changes as a function of peat concentration using a petrographic microscope and scanning electron microscope. Due to the fibrous and absorbent nature of peat, we anticipate the peat to force tightly packed clay particles in the mudstone apart resulting in a looser microstructure and increased porosity, and thus, a higher compressibility and permeability. Understanding the controls on the mechanical and flow properties of hydrocarbon-bearing, fine-grained formations is crucial for exploration and successful production from hydrocarbon reservoirs. Additionally, this study has large implications for soil water storage and soil amendment to improve plant growth and health in clayey soils.

The importance of pH and sand substrate in the revegetation of saline non-waterlogged peat fields.

PubMed

Montemayor, Marilou B; Price, Jonathan; Rochefort, Line

2015-11-01

A partially peat-extracted coastal bog contaminated by seawater was barren and required revegetation as a wetland. Peat fields were rectangular in shape, cambered in cross-section profile, and separated by drainage ditches. Common to all peat fields were symmetrical patterns in micro-topography with slopes between differences in elevation. Saline non-waterlogged slopes of ∼5% occurred as a symmetrical pair on each side of the crest of the cambered profile, at one end of each peat field. Three rows were laid across this slope (Top, Middle, and Bottom rows) and transplanted with naturally-growing plant species with their sand substrate, in three experiments, and grown for a year. In the Spartina pectinata experiment, bare root stem sections were also planted. Another experiment was conducted to determine changes in the characteristics of a volume of sand when incubated in saline peat fields. We found the salinity of peat increased with moisture downslope, and pH decreased with increase in salinity. S. pectinata grew best when planted with its sand substrate compared with bare root stem section, and when planted in Bottom rows. Juncus balticus had excellent growth in all rows. Unexpectedly, Festuca rubra that was inconspicuous beneath the J. balticus canopy in the natural donor site grew densely within the J. balticus sods. Agrostis stolonifera grew well but seemed to show intolerance to the surrounding acidic peat by curling up its stolons. The pH of the incubated sand volume was much higher than the surrounding peat. These studies suggest that recognition of plant niches and pH manipulation are important in the revegetation of disturbed Sphagnum peatlands that are found abundantly in the northern hemisphere. Results are also relevant to the reclamation of other disturbed lands. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mercury Pollution Exploration in Latvia with High-Sensitivity Zeeman Atomic Absorption Spectrometry

NASA Astrophysics Data System (ADS)

Bogans, Egils; Gavare, Zanda; Svagere, Anda; Poikane, Rita; Skudra, Jānis

2011-01-01

This research presents Hg pollution measurements performed in Latvia with sensitive method using Zeeman AAS analyzer RA-915+ and necessary attachments. Air in Riga city and water samples from a number of rivers and lakes of Latvia were analyzed for presence of low-level Hg concentrations. Ombrotrophic bog peat was analyzed to get insight into long-term trends. Environment in the sites sampled is relatively clean according to the results obtained, but there are local spots of pollution.

Atmospheric fallout radionuclides in peatland from Southern Poland.

PubMed

Mróz, Tomasz; Łokas, Edyta; Kocurek, Justyna; Gąsiorek, Michał

2017-09-01

Two peat profiles were collected in a peat bog located in Southern Poland and their geochronology were determined using 210 Pb, 238,239+240 Pu and 137 Cs radiometric techniques. The 210 Pb chronologies were established using the constant rate of supply model (CRS) and are in good agreement with the Pu isotopes and 137 Cs time markers. Maximum activities of Pu isotopes were found at a depth corresponding to the early 1960s, which is the period characterized by the maximum nuclear weapon tests. The results showed that the 210 Pb method is the most accurate technique for the determination age and accumulation rate of a peat. The next part of this study calculated linear accumulation rates by analyzing 238,239+240 Pu and 137 Cs vertical distributions in the profiles. Activities of fallout isotopes were also measured in plants covering the peatland. The highest activities of 137 Cs and 210 Pb were found in Calluna vulgaris samples, and 239+240 Pu were found only in two samples (C. vulgaris and leaves of Oxycoccus quadripelatus). Copyright © 2017 Elsevier Ltd. All rights reserved.

Decomposition rate of peat-forming plants in the oligotrophic peatland at the first stages of destruction

NASA Astrophysics Data System (ADS)

Nikonova, L. G.; Golovatskaya, E. A.; Terechshenko, N. N.

2018-03-01

The research presents quantitative estimates of the decomposition rate of plant residues at the initial stages of the decay of two plant species (Eriophorum vaginatum and Sphagnum fuscum) in a peat deposit of the oligotrophic bog in the southern taiga subzone of Western Siberia. We also studied a change in the content of total carbon and nitrogen in plant residues and the activity of microflora in the initial stages of decomposition. At the initial stage of the transformation process of peat-forming plants the losses of mass of Sph. fuscum is 2.5 times lower then E. vaginatum. The most active mass losses, as well as a decrease in the total carbon content, is observed after four months of the experiment. The most active carbon removal is characteristic for E. vaginatum. During the decomposition of plant residues, the nitrogen content decreases, and the most intense nitrogen losses were characteristic for Sph. fuscum. The microorganisms assimilating organic and mineral nitrogen are more active in August, the oligotrophic and cellulolytic microorganisms – in July.

Dust is the dominant source of "heavy metals" to peat moss (Sphagnum fuscum) in the bogs of the Athabasca Bituminous Sands region of northern Alberta.

PubMed

Shotyk, William; Bicalho, Beatriz; Cuss, Chad W; Duke, M John M; Noernberg, Tommy; Pelletier, Rick; Steinnes, Eiliv; Zaccone, Claudio

2016-01-01

Sphagnum fuscum was collected from twenty-five ombrotrophic (rain-fed) peat bogs surrounding open pit mines and upgrading facilities of Athabasca Bituminous Sands (ABS) in northern Alberta (AB) in order to assess the extent of atmospheric contamination by trace elements. As a control, this moss species was also collected at a bog near Utikuma (UTK) in an undeveloped part of AB and 264km SW of the ABS region. For comparison, this moss was also collected in central AB, in the vicinity of the City of Edmonton which is approximately 500km to the south of the ABS region, from the Wagner Wetland which is 22km W of the City, from Seba Beach (ca. 90km W) and from Elk Island National Park (ca. 45km E). All of the moss samples were digested and trace elements concentrations determined using ICP-SMS at a commercial laboratory, with selected samples also analyzed using instrumental neutron activation analysis at the University of Alberta. The mosses from the ABS region yielded lower concentrations of Ag, As, Bi, Cd, Cu, Pb, Sb, Tl, and Zn compared to the moss from the Edmonton area. Concentrations of Ni and Mo in the mosses were comparable in these two regions, but V was more abundant in the ABS samples. Compared with the surface vegetation of eight peat cores collected in recent years from British Columbia, Ontario, Quebec and New Brunswick, the mean concentrations of Ag, As, Bi, Cd, Cu, Mo, Ni, Pb, Sb, Tl and Zn in the mosses from the ABS region are generally much lower. In fact, the concentrations of these trace elements in the samples from the ABS region are comparable to the corresponding values in forest moss from remote regions of central and northern Norway. Lithophile element concentrations (Ba, Be, Ga, Ge, Li, Sc, Th, Ti, Zr) explain most of the variation in trace metal concentrations in the moss samples. The mean concentrations of Th and Zr are greatest in the moss samples from the ABS region, reflecting dust inputs to the bogs from open pit mines, aggregate quarries, and gravel roads. Linear regressions of V, Ni, and Mo (elements enriched in bitumen) versus Sc (a conservative, lithophile element) show excellent correlations in the mosses from the ABS region, but this is true also of Ag, Pb, Sb and Tl: thus, most of the variation in the trace metal concentrations can be explained simply by the abundance of dust particles on the plants of this region. Unlike the moss samples from the ABS region and from UTK where Pb/Sc ratios resemble those of crustal rocks, the moss samples from the other regions studied yielded much greater Pb/Sc ratios implying significant anthropogenic Pb contributions at these other sites. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exploring spatial heterogeneity and resilience in northern peatlands

NASA Astrophysics Data System (ADS)

Malhotra, A.; Roulet, N. T.

2011-12-01

Northern peatlands cover only 3% of the worlds land area while storing approximately 30% of the world's soil carbon making them important players in the global and regional carbon (C) cycle (Gorham 1991). Current peatland research attempts to predict changes in peatland biogeochemistry given climate change scenarios. However, the focus is primarily on linear responses to changes rather than on self regulation properties that are present in complex systems. Studying peatlands as complex adaptive systems (CAS) is important to fully understand peatland resilience and therefore to better predict response to disturbances. Peatlands possess properties of CAS such as spatial heterogeneity (SH), localized flows, self-organizing structures and non-linearity (Belyea and Baird 2006). The broad hypothesis of our proposed research is that SH in peatlands is positively connected with ecosystem resilience. To address our broad hypothesis we propose to 1) characterize SH in peatlands (using two visible indices of microtopography [MT] and vegetation structure [VEG]), 2) quantify the auto-correlation between visible SH and biogeochemical parameters and 3) investigate short term resilience using the response of biogeochemical parameters to environmental changes. The selection of biogeochemical parameters is based on prevalent theories on the persistence of MT in peatlands and parameters are related to peat accumulation (function of decomposition and net primary production; NPP), hydrology and nutrients (Swanson and Grigal 1988, Belyea and Clymo 2001, Eppinga et al. 2009). Field measurements will be conducted in the Stordalen mire in Abisko, Sweden. This site provides a steep environmental gradient with the presence of 3 peatland types- palsa, bog and fen. Each of these peatland types have varying degrees of spatial heterogeneity, exogenous controls (related to hydrology and permafrost), and therefore hypothesized varying degrees of resilience. Measurements will include nutrients, NPP, decomposition, surface topography, vegetation distribution, hydrology and environmental parameters. Preliminary data will be presented on the auto-correlation between MT, VEG and plant tissue nutrient in bog, fen and palsa peatland subtypes in Stordalen. We hypothesize a tighter auto-correlation between SH and nutrients in the more self-regulated system (bog) vs less self-regulated systems (palsa and fen). This research aims to provide insight into peatland self-regulation as well as improve current peatland models by generating high resolution spatial data on SH and biogeochemical parameters. Belyea, LR Baird, A. (2006). Beyond "the limits to peat bog growth": Cross-scale feedback in peatland development. Ecological Monographs, 76(3), 299-322 Belyea, L R, & Clymo, R S. (2001). Feedback control of the rate of peat formation. Proceedings. Biological sciences / The Royal Society, 268(1473), 1315-21 Eppinga, M. B., Ruiter, P. C. de, Wassen, Martin J, & Rietkerk, Max. (2009). Nutrients and hydrology indicate the driving mechanisms of peatland surface patterning. The American naturalist, 173(6), 803-18 Gorham, E. (1991). Northern Peatlands : Role in the Carbon Cycle and Probable Responses to Climatic Warming. Ecological Applications, 1(2), 182-195 Swanson, D. K., & Grigal, D. F. (1988). A Simulation Model of Mire Patterning. Oikos, 53(3), 309

Seasonal patterns and controls on net ecosystem CO2 exchange in a boreal peatland complex

NASA Astrophysics Data System (ADS)

Bubier, Jill L.; Crill, Patrick M.; Moore, Tim R.; Savage, Kathleen; Varner, Ruth K.

1998-12-01

We measured seasonal patterns of net ecosystem exchange (NEE) of CO2 in a diverse peatland complex underlain by discontinuous permafrost in northern Manitoba, Canada, as part of the Boreal Ecosystems Atmosphere Study (BOREAS). Study sites spanned the full range of peatland trophic and moisture gradients found in boreal environments from bog (pH 3.9) to rich fen (pH 7.2). During midseason (July-August, 1996), highest rates of NEE and respiration followed the trophic sequence of bog (5.4 to -3.9 μmol CO2 m-2 s-1) < poor fen (6.3 to -6.5 μmol CO2 m-2 s-1) < intermediate fen (10.5 to -7.8 μmol CO2 m-2 s-1) < rich fen (14.9 to -8.7 μmol CO2m-2 s-1). The sequence changed during spring (May-June) and fall (September-October) when ericaceous shrub (e.g., Chamaedaphne calyculata) bogs and sedge (Carex spp.) communities in poor to intermediate fens had higher maximum CO2 fixation rates than deciduous shrub-dominated (Salix spp. and Betula spp.) rich fens. Timing of snowmelt and differential rates of peat surface thaw in microtopographic hummocks and hollows controlled the onset of carbon uptake in spring. Maximum photosynthesis and respiration were closely correlated throughout the growing season with a ratio of approximately 1/3 ecosystem respiration to maximum carbon uptake at all sites across the trophic gradient. Soil temperatures above the water table and timing of surface thaw and freeze-up in the spring and fall were more important to net CO2 exchange than deep soil warming. This close coupling of maximum CO2 uptake and respiration to easily measurable variables, such as trophic status, peat temperature, and water table, will improve models of wetland carbon exchange. Although trophic status, aboveground net primary productivity, and surface temperatures were more important than water level in predicting respiration on a daily basis, the mean position of the water table was a good predictor (r2 = 0.63) of mean respiration rates across the range of plant community and moisture gradients. Q10 values ranged from 3.0 to 4.1 from bog to rich fen, but when normalized by above ground vascular plant biomass, the Q10 for all sites was 3.3.

Atmospheric Pb and Ti accumulation rates from Sphagnum moss: dependence upon plant productivity.

PubMed

Kempter, H; Krachler, M; Shotyk, W

2010-07-15

The accumulation rates of atmospheric Pb and Ti were obtained using the production rates of Sphagnum mosses collected in four ombrotrophic bogs from two regions of southern Germany: Upper Bavaria (Oberbayern, OB) and the Northern Black Forest (Nordschwarzwald, NBF). Surfaces of Sphagnum carpets were marked with plastic mesh and one year later the production of plant matter was harvested. Metal concentrations were determined in acid digests using sector field ICP-MS employing well established analytical procedures. Up to 12 samples (40 x 40 cm) were collected per site, and 6-10 sites were investigated per bog. Variations within a given sampling site were in the range 2.3-4x for Pb concentrations, 1.8-2.5x for Ti concentrations, 3-8.3x for Pb/Ti, 5.6-7.8x for Pb accumulation rates, and 2.3-6.4x for Ti accumulation rates. However, the median values of these parameters for the sites (6-10 per bog) were quite consistent. The mosses from the bogs in NBF exhibited significantly greater productivity (187-202 g m(-2) a(-1)) compared to the OB peat bogs (71-91 g m(-2) a(-1)), and these differences had a pronounced effect on the Pb and Ti accumulation rates. Highly productive mosses showed no indication of a "dilution effect" of Pb or Ti concentrations, suggesting that more productive plants were simply able to accumulate more particles from the air. The median rates of net Pb accumulation by the mosses are in excellent agreement with the fluxes obtained by direct atmospheric measurements at nearby monitoring stations in both regions (EMEP and MAPESI data).

Impact of hydrological variations on modeling of peatland CO2 fluxes: Results from the North American Carbon Program site synthesis

NASA Astrophysics Data System (ADS)

Sulman, Benjamin N.; Desai, Ankur R.; Schroeder, Nicole M.; Ricciuto, Dan; Barr, Alan; Richardson, Andrew D.; Flanagan, Lawrence B.; Lafleur, Peter M.; Tian, Hanqin; Chen, Guangsheng; Grant, Robert F.; Poulter, Benjamin; Verbeeck, Hans; Ciais, Philippe; Ringeval, Bruno; Baker, Ian T.; Schaefer, Kevin; Luo, Yiqi; Weng, Ensheng

2012-03-01

Northern peatlands are likely to be important in future carbon cycle-climate feedbacks due to their large carbon pools and vulnerability to hydrological change. Use of non-peatland-specific models could lead to bias in modeling studies of peatland-rich regions. Here, seven ecosystem models were used to simulate CO2fluxes at three wetland sites in Canada and the northern United States, including two nutrient-rich fens and one nutrient-poor,sphagnum-dominated bog, over periods between 1999 and 2007. Models consistently overestimated mean annual gross ecosystem production (GEP) and ecosystem respiration (ER) at all three sites. Monthly flux residuals (simulated - observed) were correlated with measured water table for GEP and ER at the two fen sites, but were not consistently correlated with water table at the bog site. Models that inhibited soil respiration under saturated conditions had less mean bias than models that did not. Modeled diurnal cycles agreed well with eddy covariance measurements at fen sites, but overestimated fluxes at the bog site. Eddy covariance GEP and ER at fens were higher during dry periods than during wet periods, while models predicted either the opposite relationship or no significant difference. At the bog site, eddy covariance GEP did not depend on water table, while simulated GEP was higher during wet periods. Carbon cycle modeling in peatland-rich regions could be improved by incorporating wetland-specific hydrology and by inhibiting GEP and ER under saturated conditions. Bogs and fens likely require distinct plant and soil parameterizations in ecosystem models due to differences in nutrients, peat properties, and plant communities.

Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost

USGS Publications Warehouse

Euskirchen, Eugenie S; Edgar, C.W.; Turetsky, M.R.; Waldrop, Mark P.; Harden, Jennifer W.

2016-01-01

Changes in vegetation and soil properties following permafrost degradation and thermokarst development in peatlands may cause changes in net carbon storage. To better understand these dynamics, we established three sites in Alaska that vary in permafrost regime, including a black spruce peat plateau forest with stable permafrost, an internal collapse scar bog formed as a result of thermokarst, and a rich fen without permafrost. Measurements include year-round eddy covariance estimates of carbon dioxide (CO2), water, and energy fluxes, associated environmental variables, and methane (CH4) fluxes at the collapse scar bog. The ecosystems all acted as net sinks of CO2 in 2011 and 2012, when air temperature and precipitation remained near long-term means. In 2013, under a late snowmelt and late leaf out followed by a hot, dry summer, the permafrost forest and collapse scar bog were sources of CO2. In this same year, CO2 uptake in the fen increased, largely because summer inundation from groundwater inputs suppressed ecosystem respiration. CO2 exchange in the permafrost forest and collapse scar bog was sensitive to warm air temperatures, with 0.5 g C m−2 lost each day when maximum air temperature was very warm (≥29°C). The bog lost 4981 ± 300 mg CH4 m−2 between April and September 2013, indicating that this ecosystem acted as a significant source of both CO2 and CH4 to the atmosphere in 2013. These results suggest that boreal peatland responses to warming and drying, both of which are expected to occur in a changing climate, will depend on permafrost regime.

Mitigation of greenhouse gas emission on abandoned peatlands by growing reed canary grass

NASA Astrophysics Data System (ADS)

Järveoja, J.; Laht, J.; Soosaar, K.; Maddison, M.; Ostonen, I.; Mander, Ü.

2012-04-01

We used combined closed-chamber and plant biomass techniques to study the impact of reed canary grass (RCG, Phalaris arundinacea) cultivation on greenhouse gas (GHG) fluxes and carbon balance of an abandoned peat extraction area in Lavassaare, Estonia (N58°34'20''; E24°23'15''). Three core study sites were chosen within the abandoned peat extraction area: (I) bare peat soil (abandoned and not planted site), (II) non-fertilized Phalaris site, (III) and fertilized Phalaris site (all on drained Fibric Histosols). In addition, (IV) the natural raised bog (Fibric Histosol) and (V) the cultivated fen meadow (drained Sapric Histosol) served as reference sites. The CO2, CH4 and N2O fluxes were determined using the closed-chamber method once a month from May 2010 to December 2011. White 60 L chambers made of PVC and sealed with a water-filled ring on the soil surface were installed in 5 replicates on each site. The gas was sampled 3 times per hour in 100 mL pre-evacuated glass bottles, and in the lab the gas concentrations were measured using the Shimadzu GC-2014 (ECD, FID) gas-chromatographic system combined with a Loftfield autosampler. Measurements of groundwater level and soil temperature (10, 20, 30, and 40 cm depths) were performed simultaneously. Biomass assessments of RCG were carried out just after maximal growth of macrophytes, in early September 2010, in April 2011 just after snow melt (time of minimum aboveground biomass), and again in September 2011. Aboveground biomass samples were collected from 1×1m plots. Belowground biomass samples were collected at a depth of 25 cm in 3 replicates adjacent to each chamber using a 10×10 cm auger. Samples were analyzed for N, P and C. Our results showed high nitrous oxide emissions (up to 541 μg N2O-N m-2 h-1) from the fen meadow and high methane emissions from the natural raised bog (up to 12915 μg CH4-C m-2 h-1). The low CH4 emission from the Phalaris plots and bare soil was due to the deeper water table (up to 85 cm below ground) and high sulfur concentration in peat (up to 23 g kg-1), which probably inhibited methanogenesis. The high CO2 emission on fertilized and non-fertilized Phalaris plots in comparison to the bare peat site was probably caused by: (1) the higher plant biomass: more dissolved C coming from roots and greater amount of fine root turnover, (2) the influence of fresh plant litter on the peat mineralization on Phalaris plots, and (3) inhibited mineralization by recalcitrant C of bare peat. Our results demonstrated that as a total, the Phalaris sites acted as net carbon sinks, sequestering C in the amount of 6929.5 and 6083.5 kg CO2-C ha-1 yr-1 on the fertilized and non-fertilized plots, respectively, whereas the bare peat site acted as a carbon source (emitting 687.5 kg CO2-C ha-1 yr-1).

Hydrologic controls on DOC, As and Pb export from a polluted peatland - the importance of heavy rain events, antecedent moisture conditions and hydrological connectivity

NASA Astrophysics Data System (ADS)

Broder, T.; Biester, H.

2015-03-01

Bogs can store large amounts of lead (Pb) and arsenic (As) attributed to atmospheric deposition of anthropogenic emissions. Pb and As are exported along with dissolved organic carbon (DOC) in these organic-rich systems, but it is not yet clear which hydrological (pre-)conditions favor their export. This study combines one year continuous monitoring of precipitation, bog water level and pore water concentration changes with bog discharge, DOC, As and Pb stream concentrations and fluxes. Concentrations ranged from 5 to 30 mg L-1 for DOC, 0.2 to 1.9 μg L-1 for As and 1.3 to 12 μg L-1 for Pb with highest concentrations in late summer. As and Pb concentrations significantly correlated with DOC concentrations. Fluxes depended strongly on discharge, as 40% of As and 43% of Pb were exported by the upper 10% of discharge, pointing out the over-proportional contribution of heavy rain and high discharge events to annual As, Pb and DOC export. Exponential increase in element export from the bog is explained by connection of additional DOC, As and Pb pools in the acrotelm during water table rise, which is most pronounced after drought. Pb, As and DOC concentrations in pore water provide evidence of an increase of the soluble Pb pool as soon as the peat layer gets hydrologically connected, while DOC and As peak concentrations in runoff lag in comparison to Pb. Our data indicates a distinct bog-specific discharge threshold of 8 L s-1, which is thought to depend mainly on the bogs size and drainage conditions. Above this threshold element concentration do not further increase and discharge gets diluted. Combining pore water and discharge data shows that As and Pb exports are not only dependent on the amount of precipitation and discharge, but on the frequency and depth of water table fluctuations. Comparing the annual bog As and Pb export with element inventories indicates that As is much more mobilized than Pb, with annual fluxes accounting for 0.85 and 0.27‰ of total As and Pb inventory, respectively.

Methylocystis bryophila sp. nov., a facultatively methanotrophic bacterium from acidic Sphagnum peat, and emended description of the genus Methylocystis (ex Whittenbury et al. 1970) Bowman et al. 1993.

PubMed

Belova, Svetlana E; Kulichevskaya, Irina S; Bodelier, Paul L E; Dedysh, Svetlana N

2013-03-01

A novel species is proposed for two facultatively methanotrophic representatives of the genus Methylocystis, strains H2s(T) and S284, which were isolated from an acidic (pH 4.3) Sphagnum peat-bog lake (Teufelssee, Germany) and an acidic (pH 3.8) peat bog (European North Russia), respectively. Cells of strains H2s(T) and S284 are aerobic, Gram-negative, non-motile, curved coccoids or short rods that contain an intracytoplasmic membrane system typical of type-II methanotrophs. They possess both a soluble and a particulate methane monooxygenase (MMO); the latter is represented by two isozymes, pMMO1 and pMMO2. The preferred growth substrates are methane and methanol. In the absence of C1 substrates, however, these methanotrophs are capable of slow growth on acetate. Atmospheric nitrogen is fixed by means of an aerotolerant nitrogenase. Strains H2s(T) and S284 grow between pH 4.2 and 7.6 (optimum pH 6.0-6.5) and at 8-37 °C (optimum 25-30 °C). The major fatty acids are C18 : 1ω8c, C18 : 1ω7c and C16 : 1ω7c; the major quinone is Q-8. The DNA G+C content is 62.0-62.3 mol%. Strains H2s(T) and S284 share identical 16S rRNA gene sequences, which displayed 96.6-97.3 % similarity to sequences of other taxonomically characterized members of the genus Methylocystis. Therefore, strains H2s(T) and S284 are classified as members of a novel species, for which the name Methylocystis bryophila sp. nov. is proposed; strain H2s(T) ( = DSM 21852(T)  = VKM B-2545(T)) is the type strain.

Response of Sphagnum fuscum to Nitrogen Deposition: A Case Study of Ombrogenous Peatlands in Alberta, Canada

USGS Publications Warehouse

Vitt, D.H.; Wieder, K.; Halsey, L.A.; Turetsky, M.

2003-01-01

Peatlands cover about 30% of northeastern Alberta and are ecosystems that are sensitive to nitrogen deposition. In polluted areas of the UK, high atmospheric N deposition (as a component of acid deposition) has been considered among the causes of Sphagnum decline in bogs (ombrogenous peatlands). In relatively unpolluted areas of western Canada and northern Sweden, short-term experimental studies have shown that Sphagnum responds quickly to nutrient loading, with uptake and retention of nitrogen and increased production. Here we examine the response of Sphagnum fuscum to enhanced nitrogen deposition generated during 34 years of oil sands mining through the determination of net primary production (NPP) and nitrogen concentrations in the upper peat column. We chose six continental bogs receiving differing atmospheric nitrogen loads (modeled using a CALPUFF 2D dispersion model). Sphagnum fuscum net primary production (NPP) at the high deposition site (Steepbank - mean of 600 g/m2; median of 486 g/m2) was over three times as high than at five other sites with lower N deposition. Additionally, production of S. fuscum may be influenced to some extent by distance of the moss surface from the water table. Across all sites, peat nitrogen concentrations are highest at the surface, decreasing in the top 3 cm with no significant change with increasing depth. We conclude that elevated N deposition at the Steepbank site has enhanced Sphagnum production. Increased N concentrations are evident only in the top 1-cm of the peat profile. Thus, 34 years after mine startup, increased N-deposition has increased net primary production of Sphagnum fuscum without causing elevated levels of nitrogen in the organic matter profile. A response to N-stress for Sphagnum fuscum is proposed at 14-34 kg ha-1 yr-1. A review of N-deposition values reveals a critical N-deposition value of between 14.8 and 15.7 kg ha -1 yr-1 for NPP of Sphagnum species.

Historical Tsunami Records on Russian Island, the Sea of Japan

NASA Astrophysics Data System (ADS)

Razjigaeva, N. G.; Ganzey, L. A.; Grebennikova, T. A.; Arslanov, Kh. A.; Ivanova, E. D.; Ganzey, K. S.; Kharlamov, A. A.

2018-04-01

In this article, we provide data evidencing tsunamis on Russian Island over the last 700 years. Reconstructions are developed based on the analyses of peat bog sections on the coast of Spokoynaya Bay, including layers of tsunami sands. Ancient beach sands under peat were deposited during the final phase of transgression of the Medieval Warm Period. We used data on diatoms and benthic foraminifers to identify the marine origin of the sands. The grain size compositions of the tsunami deposits were used to determine the sources of material carried by the tsunamis. The chronology of historical tsunamis was determined based on the radiocarbon dating of the underlying organic deposits. There was a stated difference between the deposition environments during tsunamis and large storms during the Goni (2015) and Lionrock (2016) typhoons. Tsunami deposits from 1983 and 1993 were found in the upper part of the sections. The inundation of the 1993 tsunami did not exceed 20 m or a height of 0.5 m a.m.s.l. (0.3 above high tide). The more intensive tsunami of 1983 had a run-up of 0.65 m a.m.s.l. and penetrated inland from the shoreline up to 40 m. Sand layer of tsunami 1940 extend in land up to 50 m from the present shoreline. Evidence of six tsunamis was elicited from the peat bog sections, the deposits of which are located 60 m from the modern coastal line. The deposits of strong historic tsunamis in the Japan Sea region in 1833, 1741, 1614 (or 1644), 1448, the XIV-XV century and 1341 were also identified on Russian Island. Their run-ups and inundation distances were also determined. The strong historic tsunamis appeared to be more intensive than those of the XX century, and considering the sea level drop during the Little Ice Age, the inundation distances were as large as 250 m.

Historical Tsunami Records on Russian Island, the Sea of Japan

NASA Astrophysics Data System (ADS)

Razjigaeva, N. G.; Ganzey, L. A.; Grebennikova, T. A.; Arslanov, Kh. A.; Ivanova, E. D.; Ganzey, K. S.; Kharlamov, A. A.

2018-03-01

In this article, we provide data evidencing tsunamis on Russian Island over the last 700 years. Reconstructions are developed based on the analyses of peat bog sections on the coast of Spokoynaya Bay, including layers of tsunami sands. Ancient beach sands under peat were deposited during the final phase of transgression of the Medieval Warm Period. We used data on diatoms and benthic foraminifers to identify the marine origin of the sands. The grain size compositions of the tsunami deposits were used to determine the sources of material carried by the tsunamis. The chronology of historical tsunamis was determined based on the radiocarbon dating of the underlying organic deposits. There was a stated difference between the deposition environments during tsunamis and large storms during the Goni (2015) and Lionrock (2016) typhoons. Tsunami deposits from 1983 and 1993 were found in the upper part of the sections. The inundation of the 1993 tsunami did not exceed 20 m or a height of 0.5 m a.m.s.l. (0.3 above high tide). The more intensive tsunami of 1983 had a run-up of 0.65 m a.m.s.l. and penetrated inland from the shoreline up to 40 m. Sand layer of tsunami 1940 extend in land up to 50 m from the present shoreline. Evidence of six tsunamis was elicited from the peat bog sections, the deposits of which are located 60 m from the modern coastal line. The deposits of strong historic tsunamis in the Japan Sea region in 1833, 1741, 1614 (or 1644), 1448, the XIV-XV century and 1341 were also identified on Russian Island. Their run-ups and inundation distances were also determined. The strong historic tsunamis appeared to be more intensive than those of the XX century, and considering the sea level drop during the Little Ice Age, the inundation distances were as large as 250 m.

History and environmental impact of mining activity in Celtic Aeduan territory recorded in a peat bog (Morvan, France).

PubMed

Monna, F; Petit, C; Guillaumet, J P; Jouffroy-Bapicot, I; Blanchot, C; Dominik, J; Losno, R; Richard, H; Lévêque, J; Chateau, C

2004-02-01

The present study aims to document historical mining and smelting activities by means of geochemical and pollen analyses performed in a peat bog core collected around the Bibracte oppidum (Morvan, France), the largest settlement of the great Aeduan Celtic tribe (ca. 180 B.C. to 25 A.D.). The anthropogenic Pb profile indicates local mining operations starting from the Late Bronze Age, ca. cal. 1300 B.C. Lead inputs peaked at the height of Aeduan civilization and then decreased after the Roman conquest of Gaul, when the site was abandoned. Other phases of mining are recognized from the 11th century to modern times. They have all led to modifications in plant cover, probably related in part to forest clearances necessary to supply energy for mining and smelting. Zn, Sb, Cd, and Cu distributions may result from diffusional and biological processes or from the influence of groundwater and underlying mineral soil, precluding their interpretation for historical reconstruction. The abundance of mineral resources, in addition to the strategic location, might explain why early settlers founded the city of Bibracte at that particular place. About 20% of the anthropogenic lead record was accumulated before our era and about 50% before the 18th century, which constitutes a troublesome heritage. Any attempts to develop control strategies in accumulating environments should take into account past human activities in order to not overestimate the impact of contemporary pollution.

Multivariate study of trace element distribution in the geological record of Roñanzas Peat Bog (Asturias, N. Spain). Paleoenvironmental evolution and human activities over the last 8000 calyr BP.

PubMed

Gallego, José Luis R; Ortiz, José E; Sierra, Carlos; Torres, Trinidad; Llamas, J F

2013-06-01

Trace element concentrations in the Roñanzas peat bog record reveal a contribution of natural processes but the influence of anthropogenic factors predominates in the last two millenniums, particularly aerosol deposition linked to mining and industrial activities in northern Spain. We observed that the Roñanzas record can be considered a preserved environment, suitable to search for local (<50 km), regional (50-150 km) and/or long-distance human activity fingerprinting, specifically that related to the deposition of heavy metals such as Pb, Zn and Hg. We also carried out a multivariate statistical study in order to clarify the geochemical behavior of trace and major elements. Our study design represents a novel approach to assign natural vs. human contributions in peatlands. Therefore, synergies obtained by the simultaneous study of multivariate statistics and enrichment factors allow robust conclusions about paleoenvironmental evolution and human activities. Anthropogenic influence has also been reported in similar records in other parts of Europe, thereby suggesting large-scale sources for atmospheric pollution. However, here we revealed remarkable particularities, such as the association of Cd, Zn and Pb, mainly linked to regional and local factors (mining and more recently the metallurgical industry), whereas we propose that the occurrence of Hg is associated with a combination of regional factors and global atmospheric pollution. Copyright © 2013 Elsevier B.V. All rights reserved.

The effect of a reciprocal peat transplant between two contrasting Central European sites on C cycling

NASA Astrophysics Data System (ADS)

Novak, M.; Zemanova, L.; Buzek, F.; Jackova, I.; Adamova, M.; Komarek, A.; Vile, M. A.; Wieder, R. K.; Stepanova, M.

2009-10-01

An 18-month reciprocal peat transplant experiment was conducted between two peatlands in the Czech Republic. Both sites were 100% Sphagnum-covered, with no vascular plants, and no hummocks and hollows. Atmospheric depositions of sulfur were up to 10 times higher at the northern site Velke jerabi jezero (VJJ), compared to the southern site Cervene blato (CB). Forty-cm deep peat cores, 10 cm in diameter, were used as transplants and controls in five replicates. Our objective was to evaluate whether CO2 and CH4 production potentials in Sphagnum peat bogs are governed mainly by organic matter quality, or by environmental conditions. Production rates and δ13C values of CO2 and CH4 were measured in the laboratory at time t=18 months. All measured parameters converged to those of the host site, indicating that, at least in the short-term perspective, environmental conditions were a more important control of greenhouse gas emissions than organic carbon quality. Since sulfate reducers outcompete methanogens, we hypothesized that the S-polluted site VJJ should have lower methane emissions than CB. In fact, the opposite was true, with higher methane emissions from VJJ. As a first step in an effort to link C isotope composition of emitted gases and residual peat substrate, we determined whether multiple vertical δ13C profiles in peat agree. A high degree of within-site homogeneity in δ13C was found. The δ13C value increased downcore at both CB and VJJ. However, 20 cm below surface, a reversal to lower δ13C downcore was seen at VJJ. Based on 210Pb dating, peat at 20 cm depth at VJJ was only 15 years old. Increasing δ13C values in VJJ peat accumulated between 1880-1990 could not be caused by assimilation of atmospheric CO2 gradually enriched in the light isotope 12C due to fossil fuel burning.

SPRUCE Deep Peat Microbial Diversity, CO2 and CH4 Production in Response to Nutrient, Temperature, and pH Treatments during Incubation Studies.

DOE Data Explorer

A., Kluber Laurel [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Allen, Samantha A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hendershot, Nicholas [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hanson, Paul J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Schadt, Christopher W. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.

2014-09-01

This data set contains the results of a microcosm incubation study on deep peat collected from the SPRUCE experimental site in the S1 Bog in September 2014. Microcosms were monitored for CO2 and CH4 production, and microbial community dynamics were assessed using qPCR and amplicon sequencing.The experiment was designed with a full factorial design with elevated temperature, nitrogen (N), (P), and pH treatments was used with samples from each transect serving replicates. In all, 96 microcosms were constructed to account for the 16 treatment combinations (N x P x pH x temperature), 2 time points, and 3 replicates. Temperature treatments were 6 °C, to mimic the SPRUCE ambient plot temperatures, and 15 °C to mimic the SPRUCE +9 °C treatment.

Hydrogeology of the Seldovia area, Alaska

USGS Publications Warehouse

Nelson, Gordon L.; Danskin, Wesley R.

1980-01-01

Surficial materials in the Seldovia area, Alaska, are mapped as glacial drift over sedimentary bedrock, glacial drift over igneous and metamorphic bedrock, valley-bottom, alluvium, alluvial fan deposits, beach and intertidal deposits, and peat. Unconsolidated materials are generally less than 10 feet thick except in well-drained glacial deposits along the Seldovia-Jakolof Bay Road and in depressions in the bedrock surface. These depressions are poorly drained and commonly contain peat bogs. Development of domestic wells (1-15 gallons per minute) may be possible from unconsolidated materials and sedimentary bedrock, but larger water requirements must be met from surface-water sources. In areas having the water table or top of bedrock at shallow depths, effluent from sewage disposal systems may cause pollution of the land surface and nearby surface water. Seepage from hillside aquifers and unstable land along the coast of Kachemak Bay may adversely affect roads and structures. (USGS)

Features of seasonal temperature variations in peat soils of oligotrophic bogs in south taiga of Western Siberia

NASA Astrophysics Data System (ADS)

Kiselev, M. V.; Dyukarev, E. A.; Voropay, N. N.

2018-03-01

The work presents the results of the study of the peculiarities of the temperature regime in the five basic ecosystems of oligotrophic bogs in the south taiga zone of Western Siberia in 2011-2016. The soil temperature regime was studied using the atmospheric-soil measuring complex at different depths from surface down to 240 cm. All sites were divided into two groups according to the bog water level: flooded sites (hollow and open fen) and drained sites (ridge, tall and low ryam). The waterlogged sites are better warmed in the summer period and slowly freeze in the winter period. The analysis of the annual cycle of temperature showed that the maximum surface temperature is in July. The minimum temperature on the surface is observed in February or January. The greatest temperature gradient was recorded in the upper 2 cm layer. The gradient at the open fen was -2 °C/cm in February and 1.1 °C/cm in October. The peak of formation of the seasonally frozen layer occurs at the end of autumn or in the beginning of winter. The degradation of the seasonally frozen layer was observed both from top and bottom, but the degradation rate from the top is faster.

Ebullition, Plant-Mediated Transport, and Subsurface Horizontal Water Flow Dominate Methane Transport in an Arctic Sphagnum Bog

NASA Astrophysics Data System (ADS)

Wehr, R. A.; McCalley, C. K.; Logan, T. A.; Chanton, J.; Crill, P. M.; Rich, V. I.; Saleska, S. R.

2017-12-01

Emission of the greenhouse gas methane from wetlands is of prime concern in the prediction of climate change - especially emission associated with thawing permafrost, which may drive a positive feedback loop of emission and warming. In addition to the biochemistry of methane production and consumption, wetland methane emission depends critically on the transport mechanisms by which methane moves through and out of the ecosystem. We therefore developed a model of methane biochemistry and transport for a sphagnum bog representing an intermediate permafrost thaw stage in Stordalen Mire, Sweden. In order to simultaneously reproduce measured profiles of both the concentrations and isotopic compositions of both methane and carbon dioxide in the peat pore water (Fig. 1) - as well as the surface methane emission - it was necessary for the model to include ebullition, plant-mediated transport via aerenchyma, and subsurface horizontal water flow. Diffusion of gas through the pore water was relatively unimportant. As a result, 90% of the produced methane escaped the wetland rather than being consumed by methanotrophic organisms in the near-surface pore water. Our model provides a comprehensive picture of methane emission from this bog site by quantifying the vertical profiles of: acetoclastic methanogenesis, hydrogenotrophic methanogenesis, methane oxidation, aerobic respiration, ebullition, plant-mediated transport, subsurface horizontal water flow, and diffusion.

How Does Tree Density Affect Water Loss of Peatlands? A Mesocosm Experiment

PubMed Central

Limpens, Juul; Holmgren, Milena; Jacobs, Cor M. J.; Van der Zee, Sjoerd E. A. T. M.; Karofeld, Edgar; Berendse, Frank

2014-01-01

Raised bogs have accumulated more atmospheric carbon than any other terrestrial ecosystem on Earth. Climate-induced expansion of trees and shrubs may turn these ecosystems from net carbon sinks into sources when associated with reduced water tables. Increasing water loss through tree evapotranspiration could potentially deepen water tables, thus stimulating peat decomposition and carbon release. Bridging the gap between modelling and field studies, we conducted a three-year mesocosm experiment subjecting natural bog vegetation to three birch tree densities, and studied the changes in subsurface temperature, water balance components, leaf area index and vegetation composition. We found the deepest water table in mesocosms with low tree density. Mesocosms with high tree density remained wettest (i.e. highest water tables) whereas the control treatment without trees had intermediate water tables. These differences are attributed mostly to differences in evapotranspiration. Although our mesocosm results cannot be directly scaled up to ecosystem level, the systematic effect of tree density suggests that as bogs become colonized by trees, the effect of trees on ecosystem water loss changes with time, with tree transpiration effects of drying becoming increasingly offset by shading effects during the later phases of tree encroachment. These density-dependent effects of trees on water loss have important implications for the structure and functioning of peatbogs. PMID:24632565

Bibliography on Cold Regions Science and Technology. Cumulative Author Index. Volumes 38-42

DTIC Science & Technology

1988-12-01

pollution by heavy metals [1985, p.15-18, rusj 40-2749 Bad’lanova, L.I. Deformation properties of washed-up sands under permafrost conditions [1986...Columbia {I987, 93p.. engj 41-4530 DobrodMv. O.P. First result» of studying iphagnum moil« and high-bog peat for atmoepheric pollution by heavy metals ...central Yakutia [1988, p.124-130, ru»] 42-3968 Gravanhorst, G. Firn sampling for heavy metals [1983. p.33-33, gerj 38-1663 Gravcnor, C.P. Origin and

Modeling Peat Ages Using 7Be Data to Account for Downwash of 210Pb

NASA Astrophysics Data System (ADS)

Manies, K.; Fuller, C.; Jones, M.

2016-12-01

In order to determine the amount of peat, and thus carbon, which has accumulated since the last thaw event, we are interested in dating the surface layers of boreal thermokarst bogs. However, there can often be a mismatch by several decades between dates obtained using 210Pb, 14C, or 137Cs. We found that 210Pb-based dates were almost always younger than 14C-based dates. One of the limitations often cited regarding the use of 210Pb dating for peatlands is the potential for this radionuclide to be transported down the soil profile, biasing the mean accumulation rate (MAR) towards higher values which, in turn, results in younger ages at a specific horizon. 7Be, which has similar depositional behaviors as 210Pb but a much shorter half-life (53.22 days), can be used to help determine if there is movement of 210Pb through surface layers and the depths to which 210Pb-bearing particles are transported (over the mean life of 7Be). These data can then be used in new models, such as the Linked Radionuclide aCcumulation model (LRC; Landis et al., 2016, http://dx.doi.org/10.1016/ j.gca.2016.02.2013), which account for 210Pb downwash when calculating soil horizon ages. To this end, we measured 7Be within a bog four times over the growing season. 7Be was found to 4 cm in May, reached its maximum depth of penetration in July (7 cm), and then receded again to 4 cm. The maximum integrated 7Be activity was also found in July. This pattern is similar to other studies which found 7Be deposition decreased over the rainy season. Next, we will calculate peat ages with models that include downwash of 210Pb, the depths of which will be based on the penetration depth of 7Be. These ages will be compared to 210Pb ages obtained with both the Constant Rate of Supply (CRS) and Constant Flux - Constant Sedimentation (CF:CS) models and to 137Cs- and 14C-derived ages. We anticipate that dates based on models that include some transport of 210Pb into the soil profile will provide more accurate peat formation dates and allow for more accurate carbon accumulation rates.

Nutrient loading enhances methane flux in an ombrotrophic bog

NASA Astrophysics Data System (ADS)

Bubier, Jill L.; Juutinen, Sari; Moore, Tim; Arnkil, Sini; Humphreys, Elyn; Marincak, Brenden; Roy, Cameron; Larmola, Tuula

2017-04-01

Peatlands are significant sources of atmospheric methane (CH4) and emission rates may be affected by atmospheric nutrient inputs and associated changes in vegetation. In a long-term (10-15 yr) fertilization experiment at a nutrient-poor, Sphagnum moss- and dwarf shrub-dominated bog in eastern Canada, we tested the effect of ammonium nitrate (NH4NO3,0 to 6.4 g N m-2 yr-1) and potassium phosphate (KH2PO4,5 g P m-2 yr-1) on fluxes of CH4. Fluxes were measured using a closed chamber technique over the growing seasons of 2005 and 2015. The effect of long-term field treatments on aerobic consumption and anaerobic production potentials of CH4 was tested by laboratory incubations of peat samples, as well as an amendment with KH2PO4on anaerobic production potentials at the water table. Over the 10-15 yr, three levels of N plus PK addition and N-only addition of 6.4g N m-2yr-1 decreased the abundance of Sphagnum and Polytrichum mosses, increased the growth and coverage of dwarf shrubs, and caused a decline in surface elevation and thus a higher water table. Overall, CH4 flux was small, ˜ 12 mg m-2 d-1 in the control plots, primarily because of the low water table (30 to 50 cm beneath the peat surface), but flux varied as a function of water table position and treatment. KH2PO4 addition was associated with the highest fluxes: in the 5th treatment year, the PK treatment had the largest CH4 flux (˜25 mg m-2 d-1), whereas in the 15th year the 6.4NPK treatment had the largest flux (˜50 mg m-2 d-1). Rates of potential production and consumption of CH4in laboratory incubations of peat samples were associated with position relative to the water table. Anaerobic potential CH4production was largest in the PK treatment and overall was marginally increased by PK amendment; there were no clear effects of NH4NO3 on CH4 production. The major increase in CH4 flux appearing in the long term seemed to be result of the change in water table position owing to peat subsidence and loss of moss, plus potential stimulation of CH4 production by PK.

Methanogenesis limitations in degraded peatlands after their hydrological restoration

NASA Astrophysics Data System (ADS)

Urbanová, Zuzana

2017-04-01

Peatlands are ecosystems that can have a high degree of carbon sequestration due to CO2 fixation and low decomposition rates, but on the other hand, they are a source of CH4. Past drainage or mining can disturb these natural functions with rewetting being the main method used to bring back their original ecosystem properties. Methanogenic community composition and its activity seems to be very sensitive to environmental changes and therefore its limited activity after restoration can reflect the not fully restored functioning of the microbial community and its processes in the rewetted peatlands. To find the cause for this methanogenesis limitation we determined the abundance and composition of the methanogenic community and methane potential production in pristine, long-term drained and rewetted bogs and spruce swamp forests (SSF) in the Šumava Mountains (Czech Republic), using high-throughput barcoded sequencing, qPCR and anaerobic incubation of peat samples in relation to peat biochemical properties. Long-term drainage led to a strongly reduced diversity, abundance and activity of the methanogenic community in both peatland types. In restored sites, methanogenic abundance and community composition reached a pristine like state, however their activity measured as CH4 production remained as low as in drained sites. Substrate limitation was expected; therefore we further added different substrates during anaerobic incubation of the peat samples. In addition to glucose and ethanol, we added natural complex substrates from peatland plants (sedges, Sphagnum) to simulate the effect of the spreading of peatland species and their litter on methanogenic activity. The results unambiguously confirmed the limitation of methanogens by substrate availability due to the previous long-term drainage and strongly decomposed peat. The addition of natural substrates led to an increase in CH4 production, which was close to values in pristine sites. The limited CH4 production reflected a not fully restored vegetation structure with sufficient litter production. Thus, the re-establishment of peatland vegetation structure should lead to regeneration of methanogenic activity and microbial processes in restored peatlands. Moreover, the results showed that there is no risk of increased CH4 emissions in the case of nutrient poor bogs and SSF after re-wetting. For management, the methanogenic community composition, abundance and activity could be used as indicators of restoration success.

Reconstruction of postglacial landscape evolution within the eastern periphery of Chuya depression on the basis of multidisciplinary analysis of peats in Boguty river basin, SE Altai, Russia

NASA Astrophysics Data System (ADS)

Agatova, A. R.; Khazina, I. V.; Bronnikova, M. A.; Uspenskaya, O. N.; Nepop, R. K.

2018-03-01

This paper presents the results of multidisciplinary investigations of the peat-bed under hummocky permafrosted boggy meadow within the Boguty basin. For the last 7600 years 4 evolutionary phases of peatbog formation within the drained part of Low Boguty Lake bottom were established and corresponding 4 pollen complexes were described. 18 radiocarbon dates suggest some chronological bench marks of postglacial landscape evolution in the region. After degradation of Sartan glaciation about 14000 BP, trees grew in now forestless areas at 11000 BP and 8500-7800 BP. The climate in the first half of the Holocene was warmer and more humid. Accumulation of lacustrine loams within the studied peatbog occurred before 7600 BP with predominated algae Pediastrum, Zygnemataceae and Botryococcus. After the lake level lowered in the result of destructing moraine dam, two lower peat horizons were developed about 7600 – 7200 BP. An episode of significant lake desiccation (later than 7200 BP) was recorded in all proxy archives. Further rise of water supply led to increasing the number of water-bog plants, diatomaceous, euglenic and green algae. At the same time, the pollen of xerophytes began to predominate in the pollen complexes, indicating aridization. The final stage reflects stable peatbog drying and its transformation into boggy meadow, decomposition and mineralization of peat.

The cascade of C:N:P stoichiometry in an ombrotrophic peatland: from plants to peat

NASA Astrophysics Data System (ADS)

Wang, Meng; Moore, Tim R.; Talbot, Julie; Richard, Pierre J. H.

2014-01-01

Northern peatlands are important carbon (C) sinks and while the patterns of C accumulation have been frequently investigated, nitrogen (N) and phosphorus (P) accumulation are often neglected. Here we link the C:N:P stoichiometry from foliar plant tissues, through senescent litters to peat, and determine C, N and P accumulation rates at Mer Bleue Bog, eastern Canada. Average C:N:P ratios changed from 794:17:1 in the foliar tissues to 911:10:1 in litter and 1285:32:1 in acrotelm peat. The increase in C:N and C:P ratios from mature to senescent tissues is related to nutrient resorption. The increase in C:P and N:P ratios in peat, which was contrary to that observed in Canadian forest soils, may be related to plant/mycorrhizae uptake of P. The long-term apparent rates of C, N and P accumulation were 29.5 ± 2.1 (SE) g C, 0.87 ± 0.01 g N and 0.017 ± 0.002 g P m-2 yr-1, respectively. The significant correlation between the accumulation rates of N and P and that of C suggests more attention be placed on C:N:P stoichiometry in peatland biogeochemistry, in particular in understanding why C:P ratios are so large in the lower parts of the profile.

Atmospheric trace metal inputs in the Misten bog (East Belgium): Special attention to sampling techniques and site-spatial variability.

NASA Astrophysics Data System (ADS)

Allan, Mohammed; Fagel, Nathalie; de Vleeschouwer, François; Mattielli, Nadine; Piotrowska, Natalia; Sikorski, Jarek; Sonke, Jeroen E.; Le Roux, Gaël.

2010-05-01

Peat bogs have a great potential to record anthropogenic inputs via their constituting mosses, because they draw their nutrients only from the atmosphere. These atmospheric inputs can be studied thanks to geochemical characteristics such as trace metal concentrations. Coupling lead isotopes to elemental geochemistry allows one to decipher between natural (erosion of rocks) and anthropogenic (pollution due to industrial development, vehicles...) inputs. The purpose of our work was to study the pollution history of trace metals in the region of Misten (Belgium) at a local and a regional level, and to place modern industrial pollution in this region in a wider historical perspective. Four peat cores (01W, 04W, 05W and 06W) were collected in 2008 in the Misten bog (Hautes-Fagnes plateau, E-Belgium) and studied for their trace metal and lead isotopic signatures. Analyses were accompanied by coupled 210Pb-14C age models in order to estimate the mercury and lead accumulation rates in each core and compare them to other European records. The Hg record was compared to the various anthropogenic sources as determined by Pb isotopes. The Hg concentration profiles resemble those of Pb, an element known to be immobile in peatlands. The correlation between these two metals suggests a predominant anthropogenic source of Hg (and Pb). In the W06 core, low and stable Hg accumulation rates (0.9-3.1 μg m-2 yr-1) are found in the lower layers (503-1823AD). High Hg accumulation rates are found in the surface and sub-surface layers (post-1823AD) and peak at 123.3 μg m-2 yr-1 (1969AD). In 01W, the lead enrichment factor (Pb E.F.) coupled with the continuous drop in 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb isotopic ratios since 539 AD until 1973AD indicates the growing importance of the non-radiogenic Pb released from anthropogenic activities. The highest concentrations of Pb (613-662 µg g-1) have been found near the surface of the bog dated between 1902 and 1954AD. The Pb E.F. also significantly increased during the Industrial Revolution, and subsequently decreased due to the phasing out of leaded gasoline. Main results for Pb in 01W and Hg in 06W will be compared with the 2 other cores and previously published results collected in 2007 at another location in the same peatland. Differences in concentrations and chronology will be discussed in terms of (1) differences in the topography of the bog, (2) differences in the surface vegetation of the bog, which could have led to differential trapping and retention of lead, for example, and different retention of vegetation during sampling at the sites where the corers were inserted, (3) different effects induced by the operating mechanism of the corers, (4) operator-induced effects, e.g. leading to loss of surface material before or during coring.

Annual greenhouse gas budget for a bog ecosystem undergoing restoration by rewetting

NASA Astrophysics Data System (ADS)

Lee, Sung-Ching; Christen, Andreas; Black, Andrew T.; Johnson, Mark S.; Jassal, Rachhpal S.; Ketler, Rick; Nesic, Zoran; Merkens, Markus

2017-06-01

Many peatlands have been drained and harvested for peat mining, agriculture, and other purposes, which has turned them from carbon (C) sinks into C emitters. Rewetting of disturbed peatlands facilitates their ecological recovery and may help them revert to carbon dioxide (CO2) sinks. However, rewetting may also cause substantial emissions of the more potent greenhouse gas (GHG) methane (CH4). Our knowledge of the exchange of CO2 and CH4 following rewetting during restoration of disturbed peatlands is currently limited. This study quantifies annual fluxes of CO2 and CH4 in a disturbed and rewetted area located in the Burns Bog Ecological Conservancy Area in Delta, BC, Canada. Burns Bog is recognized as the largest raised bog ecosystem on North America's west coast. Burns Bog was substantially reduced in size and degraded by peat mining and agriculture. Since 2005, the bog has been declared a conservancy area, with restoration efforts focusing on rewetting disturbed ecosystems to recover Sphagnum and suppress fires. Using the eddy covariance (EC) technique, we measured year-round (16 June 2015 to 15 June 2016) turbulent fluxes of CO2 and CH4 from a tower platform in an area rewetted for the last 8 years. The study area, dominated by sedges and Sphagnum, experienced a varying water table position that ranged between 7.7 (inundation) and -26.5 cm from the surface during the study year. The annual CO2 budget of the rewetted area was -179 ± 26.2 g CO2-C m-2 yr-1 (CO2 sink) and the annual CH4 budget was 17 ± 1.0 g CH4-C m-2 yr-1 (CH4 source). Gross ecosystem productivity (GEP) exceeded ecosystem respiration (Re) during summer months (June-August), causing a net CO2 uptake. In summer, high CH4 emissions (121 mg CH4-C m-2 day-1) were measured. In winter (December-February), while roughly equal magnitudes of GEP and Re made the study area CO2 neutral, very low CH4 emissions (9 mg CH4-C m-2 day-1) were observed. The key environmental factors controlling the seasonality of these exchanges were downwelling photosynthetically active radiation and 5 cm soil temperature. It appears that the high water table caused by ditch blocking suppressed Re. With low temperatures in winter, CH4 emissions were more suppressed than Re. Annual net GHG flux from CO2 and CH4 expressed in terms of CO2 equivalents (CO2 eq.) during the study period totalled -22 ± 103.1 g CO2 eq. m-2 yr-1 (net CO2 eq. sink) and 1248 ± 147.6 g CO2 eq. m-2 yr-1 (net CO2 eq. source) by using 100- and 20-year global warming potential values, respectively. Consequently, the ecosystem was almost CO2 eq. neutral during the study period expressed on a 100-year time horizon but was a significant CO2 eq. source on a 20-year time horizon.

Linking major and trace element headwater stream concentrations to DOC release and hydrologic conditions in a bog and peaty riparian zone

NASA Astrophysics Data System (ADS)

Broder, Tanja; Biester, Harald

2017-04-01

Peatlands and organic-rich riparian zones are known to export large amounts of dissolved organic carbon (DOC) to surface water. In organic-rich, acidic headwater streams main carriers for element export are dissolved organic matter (DOM) and organic-iron complexes. In this environment DOM might also act as major carrier for metals, which otherwise may have a low solubility. This study examines annual and short term event-based variations of major and trace elements in a headwater catchment. Patterns are used to trace hydrological pathways and element sources under different hydrologic preconditions. Furthermore, it elucidates the importance of DOC as carrier of different elements in a bog and a peaty riparian catchment. The study was conducted in a small headwater stream draining an ombrotrophic peatland with an adjacent forested area with peaty riparian soils in the Harz Mountains (Germany). Discharge sampling was conducted weekly at two sites from snowmelt to begin of snowfall and in high resolution during selected discharge events in 2013 and 2014. Element concentrations were measured by means of ICP-MS and ICP-OES. A PCA was performed for each site and for annual and event datasets. Results show that a large number of element concentrations strongly correlate with DOC concentrations at the bog site. Even elements like Ca and Mg, which are known to have a low affinity to DOC. Congruently, the first principal component integrates the DOC pattern (element loadings > 0.8: Ca, Fe, Mg, Mn, Zn, As, Sr, Cd, DOC) and explained about 35 % of total variance and even 50 % during rain events (loadings > 0.8: Al, Ca, Fe, Mg, Mn, Zn, Li, Co, As, Sr, Cd, Pb, DOC). The study cannot verify that all correlating elements bind to DOC. It is likely that also a common mobilization pattern in the upper peat layer by plant decomposition causes the same response to changes in hydrologic pathways. Additionally, a low mineral content and an enrichment of elements like Fe and Mn in the upper peat layers due to prevailing redox conditions might play a major role in a bog environment. At the peaty riparian zone only Ca, Fe, and Sr strongly correlated with DOC over the annual record. The PCA of the annual record display no clear DOC component here, but indicates that DOC is influenced by Component one (element loadings > 0.8: Ca, Mg, Zn, Co, Sr) and two (Al, V, La, Pb, U) suggesting different DOC sources in the peaty riparian zone. A large number of elements correlate with DOC during rain event sampling at the riparian zone. In contrast to the bog site the event-based riparian zone PCA distinguished a clear discharge related component with mineral, groundwater related elements (K, Rb, In, Cs, NO3- and SO42-). Pattern of the mineral and DOC components prove that during base flow discharge is generated in a shallow groundwater layer and successively increases upward to the organic-rich upper soil layer with increasing discharge. Contrarily, bog element pattern confirm a dominating surface-near discharge, due to high hydraulic conductivities.

Surface deformations as indicators of deep ebullition fluxes in a large northern peatland

USGS Publications Warehouse

Glaser, P.H.; Chanton, J.P.; Morin, P.; Rosenberry, D.O.; Siegel, D.I.; Ruud, O.; Chasar, L.I.; Reeve, A.S.

2004-01-01

Peatlands deform elastically during precipitation cycles by small (??3 cm) oscillations in surface elevation. In contrast, we used a Global Positioning System network to measure larger oscillations that exceeded 20 cm over periods of 4-12 hours during two seasonal droughts at a bog and fen site in northern Minnesota. The second summer drought also triggered 19 depressuring cycles in an overpressured stratum under the bog site. The synchronicity between the largest surface deformations and the depressuring cycles indicates that both phenomena are produced by the episodic release of large volumes of gas from deep semi-elastic compartments confined by dense wood layers. We calculate that the three largest surface deformations were associated with the release of 136 g CH4 m-2, which exceeds by an order of magnitude the annual average chamber fluxes measured at this site. Ebullition of gas from the deep peat may therefore be a large and previously unrecognized source of radiocarbon depleted methane emissions from northern peatlands. Copyright 2004 by the American Geophysical Union.

Species-specific effects of elevated ozone on wetland plants and decomposition processes.

PubMed

Williamson, Jennifer; Mills, Gina; Freeman, Chris

2010-05-01

Seven species from two contrasting wetlands, an upland bog and a lowland rich fen in North Wales, UK, were exposed to elevated ozone (150 ppb for 5 days and 20 ppb for 2 days per week) or low ozone (20 ppb) for four weeks in solardomes. The rich fen species were: Molinia caerulea, Juncus subnodulosus, Potentilla erecta and Hydrocotyle vulgaris and the bog species were: Carex echinata, Potentilla erecta and Festuca rubra. Senescence significantly increased under elevated ozone in all seven species but only Molinia caerulea showed a reduction in biomass under elevated ozone. Decomposition rates of plants exposed to elevated ozone, as measured by carbon dioxide efflux from dried plant material inoculated with peat slurry, increased for Potentilla erecta with higher hydrolytic enzyme activities. In contrast, a decrease in enzyme activities and a non-significant decrease in carbon dioxide efflux occurred in the grasses, sedge and rush species. Copyright 2010 Elsevier Ltd. All rights reserved.

Use of hydraulic head to estimate volumetric gas content and ebullition flux in northern peatlands

USGS Publications Warehouse

Rosenberry, Donald O.; Glaser, Paul H.; Siegel, Donald I.; Weeks, Edwin P.

2003-01-01

Hydraulic head was overpressured at middepth in a 4.2‐m thick raised bog in the Glacial Lake Agassiz peatlands of northern Minnesota, and fluctuated in response to atmospheric pressure. Barometric efficiency (BE), determined by calculating ratios of change in hydraulic head to change in atmospheric pressure, ranged from 0.05 to 0.15 during July through November of both 1997 and 1998. The overpressuring and a BE response were caused by free‐phase gas contained primarily in the center of the peat column between two or more semielastic, semiconfining layers of more competent peat. Two methods were used to determine the volume of gas bubbles contained in the peat, one using the degree of overpressuring in the middepth of the peat, and the other relating BE to specific yield of the shallow peat. The volume of gas calculated from the overpressuring method averaged 9%, assuming that the gas was distributed over a 2‐m thick overpressured interval. The volume of gas using the BE method averaged 13%. Temporal changes in overpressuring and in BE indicate that the volume of gaseous‐phase gas also changed with time, most likely because of rapid degassing (ebullition) that allowed sudden loss of gas to the atmosphere. Estimates of gas released during the largest ebullition events ranged from 0.3 to 0.7 mol m−2 d−1. These ebullition events may contribute a significant source of methane and carbon dioxide to the atmosphere that has so far largely gone unmeasured by gas‐flux chambers or tower‐mounted sensors.

Nitrogen and 15N in the Mer Bleue peatland

NASA Astrophysics Data System (ADS)

Moore, Tim

2017-04-01

Although much of our attention in peatlands has focussed on carbon, as CO2, CH4 and DOC processing and fluxes, N plays an important role in the functioning of these ecosystems. Here, I present information on the distribution of N and 15N in plant and peat tissues and relate them to the cycling of N. N concentration in foliar tissues, ranged from 0.67 to 1.3% in evergreen shrubs and trees and mosses with little seasonal variation, and with a strong seasonal variation from 0.5 to 3.5% in the deciduous forbs, shrubs and trees, with a strong overall relationship to [chlorophyll]. Although the proportion of shrubs and mosses varied with microtopography the spatial foliar mass of N varied little with water table position, resulting in minor spatial variations in photosynthetic potential. Decomposition of plant tissues through litter to peat resulted in a decrease in the C:N ratio from about 50:1 to about 30:1 at the base of the profile, representing peat about 8000 yr old. This marginally larger loss of N through decomposition (mainly as TDN, 0.4 g N m-2 yr-1) compared to C produced a long-term N accumulation rate of 0.9 g N m-2 yr-1, being smaller in the bog phase, 0.6 N m-2 yr-1, and over past 150 yr, 0.8 g N m-2 yr-1. Although N is 'hard won' through N2 fixation, northern peatlands are significant global sinks of N and have limited N availability. del15N in foliar tissues ranged from -4 to -9 ‰ in evergreen and deciduous shrubs and trees, from -4 to -5 ‰ in mosses and from -1 to +1 ‰ in sedges and forbs. This appears to be a function of the mycorhizzal infection of the shrubs and trees, compared to sedges and forbs and the values for mosses may partially reflect the signature of atmospheric N deposition. There was no strong correlation between foliar [N] and del15N. In peat profiles from bog and fen sections of Mer Bleue, del15N values in peat fell from -5 to -2 ‰ in the top 10 cm to values of -1 to +1 ‰ at a depth of 40 cm and remained close to 0 ‰ below this. In 30-cm thick beaver pond sediments, the del15N values remained between 0 and +2 ‰. A number of processes may account for the increase in the del15N with depth in the peat profile: more rapid decomposition of tissues with larger del15N values than the slowly decomposing mosses; fractionation of N during decomposition, leaving the heavier 15N enriched in the peat; fractionation during denitrification (though denitrification potentials and emissions are small). An intriguing possibility is that methane oxidation at and just above the water table would lead to an increase in del15N, assuming the fixed N2 has a del15N close to 0.

Northern Peatland Shifts Under Changing Climate and Their Impact on Permafrost

NASA Astrophysics Data System (ADS)

Shur, Y.; Jorgenson, T.; Kanevskiy, M. Z.

2014-12-01

Formation of peatlands depends primarily on climate and its interactions with hydrology, soil thermal regimes, plant composition, and nutrients. A water balance with precipitation exceeding evaporation is necessary for their formation. The rate of peat accumulation also greatly depends on thermal resources. The prominent impact of the water balance and temperature on peatland formation is evident in the West Siberia Lowland. The rate of peat accumulation steadily increases from arctic tundra to moss tundra, to forest tundra, to northern taiga, and to southern taiga. This increase is a result in increase in air temperature and length of the growing season because all of these zones have water balance favorable for peat formation. Further to south, evaporation prevails over precipitation and peat formation occurs only in isolated areas. Climate change will redefine geographical distribution of climatic and vegetation zones. It is predicted that in arctic and subarctic regions the difference between precipitation and evaporation will increase and as a result these regions will remain favorable to peat accumulation. With increase of thermal resources, the rate of peat accumulation will also increase. The Alaska Arctic Coastal Plain is of a special interest because it has thousands of shallow lakes, which due to warming climate would shift from open waterbodies to peatlands through shoreline paludification and infilling. The accumulation of organic matter will likely turn open water into shore fens and bogs, and eventually to peat plateaus, as is occurring in many boreal landscapes. Expected impact on permafrost in arctic and subarctic regions will include rise of the permafrost table, thickening of the ice-rich intermediate layer with ataxitic (suspended) cryostructure, and replacement of frost boils with earth hummocks. In the contemporary continuous permafrost zone, permafrost formed as climate-driven will be transformed into climate-driven ecosystem protected. Sphagnum mosses, which grow better under warm climates, is a dominant factor in this transformation. Terrestrialization of numerous shallow lakes on the Arctic Coastal Plain of Alaska will lower permafrost temperatures beneath them and in surrounding areas.

Anthropogenic contributions to atmospheric Hg, Pb and As accumulation recorded by peat cores from southern Greenland and Denmark dated using the 14C "bomb pulse curve"

NASA Astrophysics Data System (ADS)

Shotyk, W.; Goodsite, M. E.; Roos-Barraclough, F.; Frei, R.; Heinemeier, J.; Asmund, G.; Lohse, C.; Hansen, T. S.

2003-11-01

Mercury concentrations are clearly elevated in the surface and sub-surface layers of peat cores collected from a minerotrophic ("groundwater-fed") fen in southern Greenland (GL) and an ombrotrophic ("rainwater-fed") bog in Denmark (DK). Using 14C to precisely date samples since ca. AD 1950 using the "atmospheric bomb pulse," the chronology of Hg accumulation in GL is remarkably similar to the bog in DK where Hg was supplied only by atmospheric deposition: this suggests not only that Hg has been supplied to the surface layers of the minerotrophic core (GL) primarily by atmospheric inputs, but also that the peat cores have preserved a consistent record of the changing rates of atmospheric Hg accumulation. The lowest Hg fluxes in the GL core (0.3 to 0.5 μg/m 2/yr) were found in peats dating from AD 550 to AD 975, compared to the maximum of 164 μg/m 2/yr in AD 1953. Atmospheric Hg accumulation rates have since declined, with the value for 1995 (14 μg/m 2/yr) comparable to the value for 1995 obtained by published studies of atmospheric transport modelling (12 μg/m 2/yr). The greatest rates of atmospheric Hg accumulation in the DK core are also found in the sample dating from AD 1953 and are comparable in magnitude (184 μg/m 2/yr) to the GL core; again, the fluxes have since gone into strong decline. The accumulation rates recorded by the peat core for AD 1994 (14 μg/m 2/yr) are also comparable to the value for 1995 obtained by atmospheric transport modelling (18 μg/m 2/yr). Comparing the Pb/Ti and As/Ti ratios of the DK samples with the corresponding crustal ratios (or "natural background values" for preanthropogenic peat) shows that the samples dating from 1953 also contain the maximum concentration of "excess" Pb and As. The synchroneity of the enrichments of all three elements (Hg, Pb, and As) suggests a common source, with coal-burning the most likely candidate. Independent support for this interpretation was obtained from the Pb isotope data ( 206Pb/ 207Pb = 1.1481 ± 0.0002 in the leached fraction and 1.1505 ± 0.0002 in the residual fraction) which is too radiogenic to be explained in terms of gasoline lead alone, but compares well with values for U.K. coals. In contrast, the lowest values for 206Pb/ 207Pb in the DK profile (1.1370 ± 0.0003 in the leached fraction and 1.1408 ± 0.0003 in the residual fraction) are found in the sample dating from AD 1979: this shows that the maximum contribution of leaded gasoline occurred approximately 25 yr after the zenith in total anthropogenic Pb deposition.

Late-Holocene environmental and climatic changes in central part of the Western Sayan Mountain

NASA Astrophysics Data System (ADS)

Grenaderova, Anna; Sharafutdinov, Ruslan

2016-04-01

The purpose of this collaborative research is to determine how Holocene climate variability affects the landscapes evolution in valley of Buyba River. The work was conducted at the intersection of three disciplines: paleobotany, mineralogy and geochemistry. Data about environmental and climate changes in the Late Holocene in central part of Western Sayan are presented. We analyzed four peatland locations that, related to a single area of the river catchment. Sediment cores were taken from the central part of the peatland landscape. The age was determined by radiocarbon dating. Start of bog forming occurred asynchronously within the northern macroslope of Western Sayan. Bogs age decreases with the increase in the absolute elevations. On the highest elevation of 1656 m, the process of peat accumulation started 460 ± 80 years ago, after a significant reduction of snowfields. The most ancient peat layers formed at the altitude of 1320 meters and in elevations down the slope, and were aged 2950 ± 110 years or more (up to 5000 years). Over the period from 5000 to 4000 years ago, there were dryer and warmer climate conditions in the research area. Slopes of trough valleys were covered with sub-alpine shrubs of dwarf birch and alder, tree layer was absent. According to the pollen analysis, the role of tree vegetation (Pinus forest with participation of Pinus sibirica and Betula sect. Albae) was larger at the foothills. At the same time, at an altitude of 1650 m peat deposits are not formed, only isolated remains of plant detritus were found in much younger gravelly-clay sediments. Shallow flowing pond conditions were characteristic for stages before peat accumulation . Geochemical analysis of the ratio Th / U in loam, underlying peat, allows one to infer about oxidizing conditions during sedimentation. Analysis of the minerals in the peat layer, and the dynamics of accumulation of Na, Al, Ti (INAA-method) indicate that the time interval 500-2200 years was characterized with most stable hydrological conditions. During this period, the flood waters have supplied the least amount of allochthonous contaminants on the surface of the swamp. On the peatlands, sedge and sedge-moss plant communities were developed. Main plant species which grows in the peatlands are Carex altaica (Gorodk.) V.Krecz, Carex limosa L. Tomentypnum nitens Hedw., Aulacomnium palustre (Hedw.) Schwaegr., Warnstorfia exannulata (B.S.G.) Loeske., Thelypteris palustris Schott, Baeothryon caespitosum (L.) A.Dietr. During the last 500 years an increase of allochthonous contaminants inputs to marsh sediments is observed. In our opinion, the main causes of the increase were reduction the forest area, sharper contrast of summer and winter temperatures and more rapid melting of snow in early summer. The last cause lead to increased levels of floods. Eutrophic-mesotrophic sphagnum communities (Sphagnum warnstorfii Russ., Sph.subsecundum Nees,, Sphagnum angustifolium Jensen., Sph. fuscum (Schimp.) Klinggr.), which are growing at the moment, begin to develop in the peatlands since 500 years ago.

High soil solution carbon and nitrogen concentrations in a drained Atlantic bog are reduced to natural levels by 10 years of rewetting

NASA Astrophysics Data System (ADS)

Frank, S.; Tiemeyer, B.; Gelbrecht, J.; Freibauer, A.

2014-04-01

Anthropogenic drainage of peatlands releases additional greenhouse gases to the atmosphere, and dissolved carbon (C) and nutrients to downstream ecosystems. Rewetting drained peatlands offers a possibility to reduce nitrogen (N) and C losses. In this study, we investigate the impact of drainage and rewetting on the cycling of dissolved C and N as well as on dissolved gases, over a period of 1 year and a period of 4 months. We chose four sites within one Atlantic bog complex: a near-natural site, two drained grasslands with different mean groundwater levels and a former peat cutting area rewetted 10 years ago. Our results clearly indicate that long-term drainage has increased the concentrations of dissolved organic carbon (DOC), ammonium, nitrate and dissolved organic nitrogen (DON) compared to the near-natural site. DON and ammonium contributed the most to the total dissolved nitrogen. Nitrate concentrations below the mean groundwater table were negligible. The concentrations of DOC and N species increased with drainage depth. In the deeply-drained grassland, with a mean annual water table of 45 cm below surface, DOC concentrations were twice as high as in the partially rewetted grassland with a mean annual water table of 28 cm below surface. The deeply drained grassland had some of the highest-ever observed DOC concentrations of 195.8 ± 77.3 mg L-1 with maximum values of >400 mg L-1. In general, dissolved organic matter (DOM) at the drained sites was enriched in aromatic moieties and showed a higher degradation status (lower DOC to DON ratio) compared to the near-natural site. At the drained sites, the C to N ratios of the uppermost peat layer were the same as of DOM in the peat profile. This suggests that the uppermost degraded peat layer is the main source of DOM. Nearly constant DOM quality through the profile furthermore indicated that DOM moving downwards through the drained sites remained largely biogeochemically unchanged. Unlike DOM concentration, DOM quality and dissolved N species distribution were similar in the two grasslands and thus unaffected by the drainage depth. Methane production during the winter months at the drained sites was limited to the subsoil, which was quasi-permanently water saturated. The recovery of the water table in the winter months led to the production of nitrous oxide around mean water table depth at the drained sites. The rewetted and the near-natural site had comparable DOM quantity and quality (DOC to DON ratio and aromaticity). 10 years after rewetting quasi-pristine biogeochemical conditions have been re-established under continuously water logged conditions in the former peat cut area. Only the elevated dissolved methane and ammonium concentrations reflected the former disturbance by drainage and peat extraction. Rewetting via polder technique seems to be an appropriate way to revitalize peatlands on longer timescales and to improve the water quality of downstream water bodies.

Nitrogen deposition does not enhance Sphagnum decomposition.

PubMed

Manninen, S; Kivimäki, S; Leith, I D; Leeson, S R; Sheppard, L J

2016-11-15

Long-term additions of nitrogen (N) to peatlands have altered bryophyte growth, species dominance, N content in peat and peat water, and often resulted in enhanced Sphagnum decomposition rate. However, these results have mainly been derived from experiments in which N was applied as ammonium nitrate (NH4NO3), neglecting the fact that in polluted areas, wet deposition may be dominated either by NO3(-) or NH4(+). We studied effects of elevated wet deposition of NO3(-) vs. NH4(+) alone (8 or 56kgNha(-1)yr(-1) over and above the background of 8kgNha(-1)yr(-1) for 5 to 11years) or combined with phosphorus (P) and potassium (K) on Sphagnum quality for decomposers, mass loss, and associated changes in hummock pore water in an ombrotrophic bog (Whim). Adding N, especially as NH4(+), increased N concentration in Sphagnum, but did not enhance mass loss from Sphagnum. Mass loss seemed to depend mainly on moss species and climatic factors. Only high applications of N affected hummock pore water chemistry, which varied considerably over time. Overall, C and N cycling in this N treated bog appeared to be decoupled. We conclude that moss species, seasonal and annual variation in climatic factors, direct negative effects of N (NH4(+) toxicity) on Sphagnum production, and indirect effects (increase in pH and changes in plant species dominance under elevated NO3(-) alone and with PK) drive Sphagnum decomposition and hummock C and N dynamics at Whim. Copyright © 2016 Elsevier B.V. All rights reserved.

The effect of temperature on growth and competition between Sphagnum species

PubMed Central

Heijmans, Monique M. P. D.; Robroek, Bjorn J. M.; Berendse, Frank

2008-01-01

Peat bogs play a large role in the global sequestration of C, and are often dominated by different Sphagnum species. Therefore, it is crucial to understand how Sphagnum vegetation in peat bogs will respond to global warming. We performed a greenhouse experiment to study the effect of four temperature treatments (11.2, 14.7, 18.0 and 21.4°C) on the growth of four Sphagnum species: S. fuscum and S. balticum from a site in northern Sweden and S. magellanicum and S. cuspidatum from a site in southern Sweden. In addition, three combinations of these species were made to study the effect of temperature on competition. We found that all species increased their height increment and biomass production with an increase in temperature, while bulk densities were lower at higher temperatures. The hollow species S. cuspidatum was the least responsive species, whereas the hummock species S. fuscum increased biomass production 13-fold from the lowest to the highest temperature treatment in monocultures. Nutrient concentrations were higher at higher temperatures, especially N concentrations of S. fuscum and S. balticum increased compared to field values. Competition between S. cuspidatum and S. magellanicum was not influenced by temperature. The mixtures of S. balticum with S. fuscum and S. balticum with S. magellanicum showed that S. balticum was the stronger competitor, but it lost competitive advantage in the highest temperature treatment. These findings suggest that species abundances will shift in response to global warming, particularly at northern sites where hollow species will lose competitive strength relative to hummock species and southern species. PMID:18283501

Spatially Explicit Simulation of Mesotopographic Controls on Peatland Hydrology and Carbon Fluxes

NASA Astrophysics Data System (ADS)

Sonnentag, O.; Chen, J. M.; Roulet, N. T.

2006-12-01

A number of field carbon flux measurements, paleoecological records, and model simulations have acknowledged the importance of northern peatlands in terrestrial carbon cycling and methane emissions. An important parameter in peatlands that influences both net primary productivity, the net gain of carbon through photosynthesis, and decomposition under aerobic and anaerobic conditions, is the position of the water table. Biological and physical processes involved in peatland carbon dynamics and their hydrological controls operate at different spatial scales. The highly variable hydraulic characteristics of the peat profile and the overall shape of the peat body as defined by its surface topography at the mesoscale (104 m2) are of major importance for peatland water table dynamics. Common types of peatlands include bogs with a slightly domed centre. As a result of the convex profile, their water supply is restricted to atmospheric inputs, and water is mainly shed by shallow subsurface flow. From a modelling perspective the influence of mesotopographic controls on peatland hydrology and thus carbon balance requires that process-oriented models that examine the links between peatland hydrology, ecosystem functioning, and climate must incorporate some form of lateral subsurface flow consideration. Most hydrological and ecological modelling studies in complex terrain explicitly account for the topographic controls on lateral subsurface flow through digital elevation models. However, modelling studies in peatlands often employ simple empirical parameterizations of lateral subsurface flow, neglecting the influence of peatlands low relief mesoscale topography. Our objective is to explicitly simulate the mesotopographic controls on peatland hydrology and carbon fluxes using the Boreal Ecosystem Productivity Simulator (BEPS) adapted to northern peatlands. BEPS is a process-oriented ecosystem model in a remote sensing framework that takes into account peatlands multi-layer canopy through vertically stratified mapped leaf area index. Model outputs are validated against multi-year measurements taken at an eddy-covariance flux tower located within Mer Bleue bog, a typical raised bog near Ottawa, Ontario, Canada. Model results for seasonal water table dynamics and evapotranspiration at daily time steps in 2003 are in good agreement with measurements with R2=0.74 and R2=0.79, respectively, and indicate the suitability of our pursued approach.

Elevated Nitrogen Deposition Enhances the Net CO2 Sink Strength in Alberta Bogs along a Post-fire Chronosequence

NASA Astrophysics Data System (ADS)

Wieder, R. K.; Vile, M. A.; Albright, C. M.; Scott, K. D.

2014-12-01

About 30% of the landscape of northern Alberta, Canada is occupied by peatlands, which persist at the low end range of both mean annual precipitation (<500 mm/yr) and mean annual atmospheric nitrogen (N) deposition (< 1 kg/ha/yr) across which peatlands are found globally. Ombrotrophic bogs in this region function as a net sink for atmospheric CO2 of over 75 g/m2/yr, taking into consideration changes in CO2 sink strength as a function of time since fire. In addition to fire, a new disturbance is emerging in the Athabasca Oil Sands Region (AOSR) of northern Alberta, where development of the oil sands resource has increased atmospheric N deposition to as much as 2.5 kg/ha/yr. To examine the effects of elevated N deposition on bog C cycling, we experimentally applied N (as NH4NO3 solutions) to replicated plots at levels equivalent to 0 (water added with no N), 10, and 20 kg/ha/yr, and controls (no waher, no N added) at five bog sites, aged at 2, 12, 32, 73, and 113 years since fire in 2013 (6 plots per N treatment per site). Understory net ecosystem exchange of CO2 (NEE) was measured repeatedly throughout the 2013 and 2014 growing season (and in 2011 and 2012 at the most recently burned site) using the closed chamber approach. Using a rectangular hyperbola equation to characterize NEE as a function of photosynthetically active radiation (PAR) and near-surface air temperature (T), monthly and annual NEE was estimated based on hourly measurements of PAR and T at each site. Across all sites, a general pattern emerged that N additions enhanced the net CO2 sink strength of the bogs, with no effect on ecosystem respiration. Net primary production of Sphagnum fuscum, the dominant peat-forming moss, was not affected by N addition, suggesting that the overall response of NEE to N addition is the result of enhanced growth of ericaceous shrubs. These findings suggest that while elevated N deposition in the AOSR may enhance the strength of the overall CO2 sink of bogs in the short term, in the longer term, increased shrub growth has the potential to shade Sphagnum mosses, compromising the future bog CO2sink strength across the region.

Hydrologic controls on DOC, As and Pb export from a polluted peatland - the importance of heavy rain events, antecedent moisture conditions and hydrological connectivity

NASA Astrophysics Data System (ADS)

Broder, T.; Biester, H.

2015-08-01

Bogs can store large amounts of lead (Pb) and arsenic (As) from atmospheric deposition of anthropogenic emissions. Pb and As are exported along with dissolved organic carbon (DOC) from these organic-rich systems, but it is not yet clear which hydrological (pre)conditions favor their export. This study combines a 1-year monitoring of precipitation, bog water level and pore water concentration changes with bog discharge and DOC, iron, As and Pb stream concentrations. From these data, annual DOC, As, and Pb exports were calculated. Concentrations ranged from 5 to 30 mg L-1 for DOC, 0.2 to 1.9 μg L-1 for As, and 1.3 to 12 μg L-1 for Pb, with highest concentrations in late summer. As and Pb concentrations significantly correlated with DOC concentrations. Fluxes depended strongly on discharge, as 40 % of As and 43 % of Pb were exported during 10 % of the time with the highest discharge, pointing out the over-proportional contribution of short-time, high-discharge events to annual As, Pb and DOC export. Exponential increase in element export from the bog is explained by connection of additional DOC, As and Pb pools in the acrotelm during water table rise, which is most pronounced after drought. Pb, As and DOC concentrations in pore water provide evidence of an increase in the soluble Pb pool as soon as the peat layer becomes hydrologically connected, while DOC and As peak concentrations in runoff lag behind in comparison to Pb. Our data indicate a distinct bog-specific discharge threshold of 8 L s-1, which is thought to depend mainly on the bogs size and drainage conditions. Above this threshold, element concentrations do not further increase and discharge becomes diluted. Combining pore water and discharge data shows that As and Pb exports are dependent on not only the amount of precipitation and discharge but also on the frequency and depth of water table fluctuations. Comparing the annual bog As and Pb export with element inventories indicates that As is much more mobilized than Pb, with annual fluxes accounting for 0.85 and 0.27 ‰ of total As and Pb inventory, respectively.

Rebuilding Peatlands on Mineral Soils Utilizing Lessons Learned from Past Peatland Initiation

NASA Astrophysics Data System (ADS)

Vitt, D. H.; Koropchak, S. C.; Xu, B.; Bloise, R.; Wieder, R.; Mowbray, S.

2010-12-01

Recent surveys of peatland initiation during the past 10,000 years in northeastern Alberta have revealed that nearly all peatlands, regardless of whether they are currently bogs and fens, were initiated by paludification, or swamping of upland soils. Terrestrialization (or infilling of water bodies) rarely if ever was involved in the initiation of peatlands across the mid boreal of Canada. Although the importance of paludification as a significant natural process in the initiation of peatland ecosystems has long been known by peatland ecologists, this knowledge has not been transferred to peatland and wetland restoration methodologies. We initiated this study to determine if wetland structure and function could be re-established on mineral gas/oil pads that were originally placed on organic soils. We have attempted to emulate the paludification process by removing mineral material to near the surrounding peatland natural water level and introducing a suite of wetland plants to the rewetted mineral soils. The experimental design comprised two well sites at the Shell Carmon Creek in situ plant near Peace River, Alberta. We placed 292 2 x 2 m plots over a series of fertilizer, water level, cultivation, and amendment treatments. In this presentation, we address four questions: 1) Will locally available peatland vascular plant species establish on these wet, compacted, mineral soils? If so; 2) Are species responses affected by water level, amendment, cultivation, and fertilization treatments, 3) Are invasive weeds a concern in these re-establishment trials, and 4) Will the surrounding bog water chemistry have an effect on water in contact with the mineral soils? Results after three growing season are: 1) All three species originally planted (a sedge, a willow, and tamarack) have successfully established at both well sites; 2) Carex aquatilis has performed well and responses to differing water levels and cultivation are not significant; 3) The plant responses to amendments are, in general, not different from the control plots; 4) The abundance of weeds is significantly different among some of the amendment types; and 5) Water chemistry (pH and electrical conductivity) of the ditches is affected by the surrounding bog waters. In addition, a fifth question was asked: Can Carex aquatilis establish by seed and if so, do C. aquatilis seeds require a peat amendment? In May 2009, three blank 4 m2 plots were selected on each of the experimental well site reclamations. Half of each plot was covered with approximately 4 cm of peat and the other half remained a mineral soil substrate. Each plot half was divided into 2 halves (1 m2); one that had approximately 600 Carex aquatilis seeds scattered across it and one that had no seeds added. Results from reassessment in July 2010 showed that subplots with added seeds had more seedlings than the subplots without added seeds. There was no difference between the number of seedlings between the peat and mineral soil subplots on either site, but on one of the sites, the subplots with peat had much higher percent cover of weeds than the mineral soil subplots.

Sphagnum Moss as an Indicator of Contemporary Rates of Atmospheric Dust Deposition in the Athabasca Bituminous Sands Region.

PubMed

Mullan-Boudreau, Gillian; Belland, Rene; Devito, Kevin; Noernberg, Tommy; Pelletier, Rick; Shotyk, William

2017-07-05

Sphagnum moss was collected from ombrotrophic (rain-fed) peat bogs to quantify dust emissions from the open-pit mining and upgrading of Athabasca bituminous sands (ABS). A total of 30 bogs were sampled in the ABS region, and 5 were sampled in central Alberta. Ash was separated into the acid-insoluble ash (AIA) and acid-soluble ash (ASA) fractions using HCl. The AIA concentrations increase toward industry from 0.4 ± 0.5% to 4.7 ± 2.0% over a distance of 30 km; the control site at the Utikuma Region Study Area (URSA) yielded 0.29 ± 0.07% (n = 30). Mass accumulations rates showed similar spatial variation. The morphology and mineralogy of the AIA particles were studied using scanning electron microscopy and energy-dispersive X-ray analysis and the particle size distributions using optical methods. Particle size was more variable in moss closer to industry. Major ions in the ASA fraction showed elevated accumulation rates of Ca, K, Fe, Mg, P, and S, with P being up to 5 times greater in samples nearest industry compared to those in distal locations. Given that P has been regarded as the growth-limiting nutrient in bogs, fertilization of nutrient-poor ecosystems, such as these from fugitive emissions of dusts from open-pit mining, may have long-term ecological ramifications.

Cirque glacier on South Georgia shows centennial variability over the last 7000 years

NASA Astrophysics Data System (ADS)

Oppedal, Lea T.; Bakke, Jostein; Paasche, Øyvind; Werner, Johannes P.; van der Bilt, Willem G. M.

2018-02-01

A 7000 year-long cirque glacier reconstruction from South Georgia, based on detailed analysis of fine-grained sediments deposited downstream in a bog and a lake, suggests continued presence during most of the Holocene. Glacier activity is inferred from various sedimentary properties including magnetic susceptibility (MS), dry bulk density (DBD), loss-on-ignition (LOI) and geochemical elements (XRF), and tallied to a set of terminal moraines. The two independently dated sediment records document concurring events of enhanced glacigenic sediment influx to the bog and lake, whereas the upstream moraines afford the opportunity to calculate past Equilibrium Line Altitudes (ELA) which has varied in the order of 70 m altitude. Combined, the records provide new evidence of cirque glacier fluctuations on South Georgia. Based on the onset of peat formation, the study site was deglaciated prior to 9900±250 years ago when Neumayer tidewater glacier retreated up-fjord. Changes in the lake and bog sediment properties indicate that the cirque glacier was close to its maximum Holocene extent between 7200±400 and 4800±200 cal BP, 2700±150 and 2000±200 cal BP, 500±150-300±100 cal BP, and in the 20th century (likely 1930s). The glacier fluctuations are largely in-phase with reconstructed Patagonian glaciers, implying that they respond to centennial climate variability possibly connected to corresponding modulations of the Southern Westerly Winds.

Highly anomalous accumulation rates of C and N recorded by a relic, free-floating peatland in Central Italy

PubMed Central

Zaccone, Claudio; Lobianco, Daniela; Shotyk, William; Ciavatta, Claudio; Appleby, Peter G.; Brugiapaglia, Elisabetta; Casella, Laura; Miano, Teodoro M.; D’Orazio, Valeria

2017-01-01

Floating islands mysteriously moving around on lakes were described by several Latin authors almost two millennia ago. These fascinating ecosystems, known as free-floating mires, have been extensively investigated from ecological, hydrological and management points of view, but there have been no detailed studies of their rates of accumulation of organic matter (OM), organic carbon (OC) and total nitrogen (TN). We have collected a peat core 4 m long from the free-floating island of Posta Fibreno, a relic mire in Central Italy. This is the thickest accumulation of peat ever found in a free-floating mire, yet it has formed during the past seven centuries and represents the greatest accumulation rates, at both decadal and centennial timescale, of OM (0.63 vs. 0.37 kg/m2/yr), OC (0.28 vs. 0.18 kg/m2/yr) and TN (3.7 vs. 6.1 g/m2/yr) ever reported for coeval peatlands. The anomalously high accretion rates, obtained using 14C age dating, were confirmed using 210Pb and 137Cs: these show that the top 2 m of Sphagnum-peat has accumulated in only ~100 years. As an environmental archive, Posta Fibreno offers a temporal resolution which is 10x greater than any terrestrial peat bog, and promises to provide new insight into environmental changes occurring during the Anthropocene. PMID:28230066

Holocene development of Amazonia's oldest peatland

NASA Astrophysics Data System (ADS)

Swindles, Graeme T.; Morris, Paul J.; Whitney, Bronwen; Galka, Mariusz; Galloway, Jennifer M.; Gallego-Sala, Angela; Macumber, Andrew L.; Mullan, Donal; Smith, Mark W.; Amesbury, Matt; Roland, Thomas; Sanei, Hameed; Patterson, R. Timothy; Parry, Lauren; Charman, Dan J.; Lopez, Omar R.; Valderamma, Elvis; Watson, Elizabeth J.; Lähteenoja, Outi; Baird, Andy J.

2017-04-01

Peatlands represent some of the most carbon-dense ecosystems of Amazonia. However, little is known about the mechanisms of Amazonian peatland development and their ecohydrological dynamics over time. We present a comprehensive multiproxy dataset from Aucayacu peat dome, the oldest peatland yet discovered in Amazonia (peat initiation occurred between 8.9 and 5.8 ka cal. BP). Our dataset includes analyses of peat physical properties, carbon and nitrogen, humification, organic matter characteristics, macrofossils, pollen, charcoal and testate amoebae. Sedimentological techniques were applied to minerogenic deposits underneath the peatland to understand the nature of the floodplain environment before peat initiation. A transfer function was used to reconstruct past hydrological conditions from subfossil testate amoeba assemblages and carbon accumulation (CA) rates were determined from bulk density and percentage carbon data. A robust chronology was achieved using 210Pb and 14C (14 radiocarbon dates on a 3-m core) determinations, modelled using a Bayesian approach. We used the datasets to investigate the long-term ecohydrological development and controls on carbon accumulation in an Amazonian peat dome. The peatland developed in three distinct stages; (i) abandoned river channel with standing open water and aquatic plants; (ii) inundated forest swamp; and (iii) ombrotrophic bog ( 3.9 ka cal. BP). Local burning occurred twice during the peatland's development as evidenced by macroscopic charcoal but appears to have become more pronounced in the last 100 years. We present a conceptual model of the role of autogenic and allogenic (climate, floodplain) processes on the long-term development of the peatland and the marked variations in carbon accumulation rates over the Holocene. Amazonian peatlands are important carbon stores and ecosystems, and represent important archives of past climatic and ecological information. They should form key foci for conservation efforts.

Deciphering human-climate interactions in an ombrotrophic peat record: REE, Nd and Pb isotope signatures of dust supplies over the last 2500 years (Misten bog, Belgium)

NASA Astrophysics Data System (ADS)

Fagel, N.; Allan, M.; Le Roux, G.; Mattielli, N.; Piotrowska, N.; Sikorski, J.

2014-06-01

A high-resolution peat record from Eastern Belgium reveals the chronology of dust deposition for the last 2500 years. REE and lithogenic elements in addition to Nd and Pb isotopes were measured in a 173 cm age-dated peat profile and provide a continuous chronology of dust source and intensity. Calculated dust flux show pronounced increases c. 300 BC, 600 AD, 1000 AD, 1200 AD and from 1700 AD, corresponding to local and regional human activities combined with climate change. The Industrial Revolution samples (1700-1950 AD) are characterised by a significant enrichment in Sc-normalised REE abundance (sum REE/Sc > 25) due to intensive coal combustion. For the pre-Industrial Revolution samples, the Sc-normalised REE abundance (10 < Sum REE/Sc < 25) and the εNd variability (-13 to -9) are interpreted by a mixing between dust particles from local soils and long-range transport of desert particles. Three periods characterised by dominant-distal sources (c. 320 AD, 1000 AD and 1700 AD) are consistent with local wetter-than-average intervals as indicated by a lower degree of peat humification. Local erosion prevails during the drier (higher humification) intervals (100 AD, 600 AD). On a global scale, more distal supplies are driven during colder periods, in particular during the Oort and Maunder minima, suggesting a potential link between dust deposition and global climate. Combining REE abundance, fractionation between Light REE and Heavy REE and Nd isotope data in ombrotrophic peat allows one to distinguish between dust flux changes related to human and climate forcings.

Potentials and problems of building detailed dust records using peat archives: An example from Store Mosse (the "Great Bog"), Sweden

NASA Astrophysics Data System (ADS)

Kylander, Malin E.; Martínez-Cortizas, Antonio; Bindler, Richard; Greenwood, Sarah L.; Mörth, Carl-Magnus; Rauch, Sebastien

2016-10-01

Mineral dust deposition is a process often overlooked in northern mid-latitudes, despite its potential effects on ecosystems. These areas are often peat-rich, providing ample material for the reconstruction of past changes in atmospheric deposition. The highly organic (up to 99% in some cases) matrix of atmospherically fed mires, however, makes studying the actual dust particles (grain size, mineralogy) challenging. Here we explore some of the potentials and problems of using geochemical data from conservative, lithogenic elements (Al, Ga, Rb, Sc, Y, Zr, Th, Ti and REE) to build detailed dust records by using an example from the 8900-yr peat sequence from Store Mosse (the ;Great Bog;), which is the largest mire complex in the boreo-nemoral region of southern Sweden. The four dust events recorded at this site were elementally distinct, suggesting different dominant mineral hosts. The oldest and longest event (6385-5300 cal yr BP) sees a clear signal of clay input but with increasing contributions of mica, feldspar and middle-REE-rich phosphate minerals over time. These clays are likely transported from a long-distance source (<100 km). While dust deposition was reduced during the second event (5300-4370 cal yr BP), this is the most distinct in terms of its source character with [Eu/Eu∗]UCC revealing the input of plagioclase feldspar from a local source, possibly active during this stormier period. The third (2380-2200 cal yr BP) and fourth (1275-1080 cal yr BP) events are much shorter in duration and the presence of clays and heavy minerals is inferred. Elemental mass accumulation rates reflect these changes in mineralogy where the relative importance of the four dust events varies by element. The broad changes in major mineral hosts, grain size, source location and approximated net dust deposition rates observed in the earlier dust events of longer duration agree well with paleoclimatic changes observed in northern Europe. The two most recent dust events are much shorter in duration, which in combination with evidence of their local and regional character, may explain why they have not been seen elsewhere.

A 5 Year Study of Carbon Fluxes from a Restored English Blanket Bog

NASA Astrophysics Data System (ADS)

Worrall, F.; Dixon, S.; Evans, M.

2014-12-01

This study aimed to measure the effects of ecological restoration on blanket peat water table depths, DOC concentrations and CO2 fluxes. In April 2003 the Bleaklow Plateau, an extensive area of deep blanket peat in the Peak District National Park, northern England, was devegetated by a wildfire. As a result the area was selected for large scale restoration. In this study we considered a 5-year study of four restored sites in comparison to both an unrestored, bare peat control and to vegetated control that did not require restoration. Results suggested that sites with revegetation alongside slope stabilisation had the highest rates of photosynthesis and were the largest net (daylight hours) sinks of CO2. Bare sites were the largest net sources of CO2 and had the deepest water table depths. Sites with gully wall stabilisation were between 5-8 times more likely to be net CO2 sinks than the bare sites. Revegetation without gully flow blocking using plastic dams did not have a large effect on water table depths in and around the gullies investigated whereas a blocked gully had water table depths comparable to a naturally revegetating gully. A ten centimetre lowering in water table depth decreased the probability of observing a net CO2 sink, on a given site, by up to 30%. With respect to DOC the study showed that the average soil porewater DOC concentration on the restored sites rose significantly over the 5 year study representing a 34% increase relative to the vegetated control and an 11% increase relative to the unrestored, bare control. Soil pore water concentrations were not significantly different from surface runoff DOC concentrations and therefore restoration as conducted by this study would have contributed to water quality deterioration in the catchment. The most important conclusion of this research was that restoration interventions were apparently effective at increasing the likelihood of net CO2 sink behaviour and raising water tables on degraded, climatically marginal blanket bog. However, had water table restoration been conducted alongside revegetation then a significant decline in DOC concentrations could have also been realised.

Spatial variation in below ground carbon cycling in a pristine peatland, driven by present and past vegetation

NASA Astrophysics Data System (ADS)

Mathijssen, Paul; Knorr, Klaus-Holger; Gałka, Mariusz; Borken, Werner

2017-04-01

Peat carbon cycling is controlled by both large scale factors, such as climate and hydrological setting, and small scale factors, such as microtopography, vegetation, litter quality, and rooting depth. These small scale factors commonly vary within peatlands, causing variation in the carbon balance at different locations within the same site. Understanding the relationship between small scale carbon cycling and vegetation helps us to assess the variation of carbon dynamics of peatlands, because vegetation composition acts as an integrator of factors such as microtopography, hydrology, and nutrient level. Variation in vegetation illustrates spatial variation of these underlying factors. Furthermore, the presence of certain plant species affects carbon cycling directly through litter quality or aeration through root tissues. In order to understand these within-site variations in terms of carbon cycling, we investigated carbon accumulation, decomposition, and biogeochemistry of pore waters along a transect of peat cores with changing vegetation and water levels in an ombrotrophic peatland in southern Patagonia. The transect ran from a Sphagnum magellanicum dominated spot with relatively high water table, to intermediately wet spots with mixed Sphagnum/shrubs vegetation, or dominated by Cyperaceae, eventually to a more elevated and drier spot dominated by cushion plants (mainly Astelia pumila). There were large differences in peat accumulation rates and peat densities, with faster peat growth and lower densities under Sphagnum, but overall carbon accumulation rates were quite similar in the various microenvironments. At most plots C/N ratios decreased with depth, concurrent with increasing humification index derived from FT-IR spectra. But under cushion plants this relation was opposite: more humification with depth, but also C/N ratios increases. This reflected the differing source material at depth under the cushion plants, and that the cushion plant peat layers were formed on top of Sphagnum peat. The divergent source material throughout a peat core makes it difficult to use C/N ratios to indicate peat decomposition rates. Although the low peat density and higher C/N ratios indicate that overall carbon turnover is slow at Sphagnum plots, pore water methane concentrations were elevated. At cushion plant plots, however, higher redox potentials exist until greater depths due to aerenchymous roots, inhibiting methane production and release. Our results demonstrate that large variation exists within pristine bogs, in terms of decomposition patterns, organic matter quality, and carbon turnover pathways, corresponding to variation in surface moisture levels and vegetation. Furthermore, variation in carbon cycling properties are maintained in buried peat layers and reflect more the organic material of that layer, than the current surface carbon dynamics.

Did enhanced afforestation cause high severity peat burn in the Fort McMurray Horse River wildfire?

NASA Astrophysics Data System (ADS)

Wilkinson, S. L.; Moore, P. A.; Flannigan, M. D.; Wotton, B. M.; Waddington, J. M.

2018-01-01

Climate change mediated drying of boreal peatlands is expected to enhance peatland afforestation and wildfire vulnerability. The water table depth-afforestation feedback represents a positive feedback that can enhance peat drying and consolidation and thereby increase peat burn severity; exacerbating the challenges and costs of wildfire suppression efforts and potentially shifting the peatland to a persistent source of atmospheric carbon. To address this wildfire management challenge, we examined burn severity across a gradient of drying in a black spruce dominated peatland that was partially drained in 1975-1980 and burned in the 2016 Fort McMurray Horse River wildfire. We found that post-drainage black spruce annual ring width increased substantially with intense drainage. Average (±SD) basal diameter was 2.6 ± 1.2 cm, 3.2 ± 2.0 cm and 7.9 ± 4.7 cm in undrained (UD), moderately drained (MD) and heavily drained (HD) treatments, respectively. Depth of burn was significantly different between treatments (p < 0.001) and averaged (±SD) 2.5 ± 3.5 cm, 6.4 ± 5.0 cm and 36.9 ± 29.6 cm for the UD, MD and HD treatments, respectively. The high burn severity in the HD treatment included 38% of the treatment that experienced combustion of the entire peat profile, and we estimate that overall 51% of the HD pre-burn peat carbon stock was lost. We argue that the HD treatment surpassed an ecohydrological tipping point to high severity peat burn that may be identified using black spruce stand characteristics in boreal plains bogs. While further studies are needed, we believe that quantifying this threshold will aid in developing effective adaptive management techniques and protecting boreal peatland carbon stocks.

Interlinkages between Carbon and Water Residence Times in Peat

NASA Astrophysics Data System (ADS)

Visser, A.; Wilson, R.; Sebestyen, S.; Griffiths, N.; Chanton, J.; Veale, N.; McFarlane, K. J.; Kolka, R. K.; Guilderson, T.

2016-12-01

Peatlands play an important role in the terrestrial carbon cycle. Understanding their response to climate change is crucial to predict their role as carbon sink or source of methane and carbon dioxide to the atmosphere. The hydrology of the peatland plays a crucial role, providing anoxic conditions for peat accumulation and advective transport of nutrients and dissolved organic carbon (DOC) to methanogens at depth. The interlinkages between the hydrology and carbon-cycling at the S1 bog at the Marcell Experimental Forest were investigated as part of the SPRUCE experiment, using a combination of isotopic techniques characterizing the carbon and water ages to assess the role of advective transport in the peat pore water. Tritium and tritiogenic helium concentrations constrain the age of the pore water to less than 10 years, although gas exchange with the atmosphere complicates direct use of 3H/3He dating methods. The pore water ages further constrain the interpretation of the peat, DOC and DIC ages. While carbon-14 values of solid peat decrease from 0‰ at the surface to -550‰ (corresponding to carbon-14 ages of 8 ka) at 2m depth, the DOC and DIC shift from +50‰ to -50‰ at depth. Knowing that the advective transport time of pore water is negligible on this time scale, the shift in carbon-14 of DOC must result from peat decomposition at depth, rather than in situ aging of DOC. Combined with the DOC concentration data, the carbon-cycling rates at the SPRUCE experiment are further constrained. The integrated application of isotopes in the carbon and water cycle emphasizes the importance of understanding peatland hydrology for understanding carbon-cycle dynamics. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-675107

The 'Amstel Canal' in Amsterdam Canal construction as part of the medieval reclamation and drainage system of the Western Netherlands wilderness

NASA Astrophysics Data System (ADS)

Abrahamse, Jaap-Evert; Kosian, Menne; Weerts, Henk

2013-04-01

Usually, Amsterdam is presented as a river city, with the river Amstel as the trade route towards its hinterland, the IJ sea-branch as the portal to the world and its Dam as a focal point of transshipment and trade. Geomorphological, sedimentological, historical and historical-geographical evidence however, points towards the straight part of the Amstel, now located in Amsterdam, as a drainage canal that was dug in the aftermath of the 'Great Reclamation' of the 11th and 12th centuries. During this period, large parts of the wilderness in Utrecht and Holland were cultivated and put to agricultural use. Prior to the 'Great Reclamations', large oligotrophic (Sphagnum) peat bogs drained by small rivers were characteristic of the entire region. All along the straight Amstel canal, Sphagnum peat is found, which is indicative of the area's former peat bog conditions. The 'Amstel Canal' connected two natural meandering watercourses, one at the north and one at the south of the canal. The soil along both watercourses exists of eutrophic peat, which is indicative of repeated natural flooding. This is a strong indication of the anthropogenous origin of the straight part of the Amstel. The reason for digging the Amstel canal was not to create better trade links; it was a local component of a solution for major regional drainage problems in the provinces of Utrecht and Holland. These problems arose from the silting up of the Rhine rivermouth around 1100AD. Because of this, the precipitation surplus of the entire region could not be drained to the North Sea by this route anymore. This led to increased flooding and subsequently to conflicts between the rulers of Holland and Utrecht. In 1165AD, these conflicts reached a point where the Holy Roman Emperor intervened. The ruling of Barbarossa eventually led to a compromise: Utrecht and Holland redirected the entire drainage system of the region from the North Sea to the Zuiderzee in a concerted effort. This operation consisted of the digging of many canals and the construction of several sluice complexes. This shift from natural to man-made drainage systems was unprecedented at this scale in North-Western Europe. An unlooked-for consequence of the digging the Amstel canal and many other drainage canals during and after the Great Reclamations was the layout of a network of infrastructure that later enabled the rise of cities in Holland.

Revising Estimates of the Methane Production Pathway in Peatland Porewater Using Intramolecular Isotopic Analyses of Acetate

NASA Astrophysics Data System (ADS)

Thomas, B.; Arthur, M. A.; Freeman, K. H.

2007-12-01

Stable isotopic measurements of methane and carbon dioxide are routinely applied to environmental samples to assess the relative importance of methane production by either aceticlastic or hydrogenotrophic methanogenesis. Such estimates rely upon assumptions about isotopic fractionation during methane production and oxidation. Rigorous isotope-based pathway estimates require knowledge of the carbon isotopic composition of both carbon dioxide and acetate. In practice, technical barriers have limited measurements of the isotopic composition of whole acetate in natural samples. Yet, the estimate of whole acetate isotopic values, even when available, may not represent accurately the composition of the methyl carbon, which is, in fact, the precursor to methane. It is exceedingly rare to find carbon isotopic measurements of acetate-methyl in the literature, and, to our knowledge, the d13C of the acetate-methyl precursor to methane has never before been reported from peatland porewater samples. Extremely 13C-depleted methane, -70 permil VPDB, and 13C-enriched carbon dioxide from acidic northern peat bogs are typically interpreted as signatures of hydrogenotrophic methanogenesis. The hypothesized dominance of methane production from hydrogen in acidic bogs contrasts with the vast majority of freshwater wetlands in which aceticlastic methanogenesis dominates. Using a new technique for the online analysis of the intramolecular carbon isotopic composition of acetate in natural samples, we find the acetate-methyl in peat porewaters can be significantly depleted relative to bulk organic matter. In porewater profiles from both winter and summer, acetate is as much as 15 permil depleted relative to bulk carbon. We hypothesize that acetate- methyl isotopic depletion results from conditions that favor autotrophic acetogenesis and subsequent acetate consumption by aceticlastic methanogens. Porewater depth profiles during winter and summer illustrate depth- dependent increases in the fraction of methane derived from carbon dioxide, with deeper peat dominated by hydrogenotrophic methanogenesis, but shallow peat dominated by aceticlastic methanogens. Significant aceticlastic methane production from autotrophically produced acetate challenges the ability of hydrogen isotopic measurements of methane to represent the pathway of methanogenesis. Supplementing our field observations, intramolecular acetate measurements of incubation experiments confirm that an aceticlastic methanogen can facilitate significant acetate-carboxyl exchange with DIC. This novel technique confirms two caveats associated with whole acetate carbon isotopic data: 1, the carboxyl carbon isotopic composition may not accurately reflect the composition of the parent molecule, and 2, the acetate methyl may be derived from inorganic carbon or the fractionation effect of fermentation in acidic porewaters may be significant.

Climate-vegetation-fire interactions and their impact on long-term carbon dynamics in a boreal peatland landscape in northern Manitoba, Canada

NASA Astrophysics Data System (ADS)

Camill, Philip; Barry, Ann; Williams, Evie; Andreassi, Christian; Limmer, Jacob; Solick, Donald

2009-12-01

Climate warming may increase the size and frequency of fires in the boreal biome, possibly causing greater carbon release that amplifies warming. However, in peatlands, vegetation change may also control long-term fire and carbon accumulation, confounding simple relationships between climate, fire, and carbon accumulation. Using 17 peat cores dating to 8000 cal years B.P. from northern Manitoba, Canada, we addressed the following questions: (1) Do past climate changes correlate with shifts in peatland vegetation? (2) What is the relationship between peatland vegetation and fire severity? (3) What is the mean return interval for boreal peat fires, and how does it change across fires of different severities? (4) How does fire severity affect carbon accumulation rates? (5) Do fire and long-term carbon accumulation change directly in response to climate or indirectly though climate-driven changes in vegetation? We measured carbon accumulation rates, fire severity, and return intervals using macroscopic charcoal and changes in vegetation using macrofossils. Climate and vegetation changes covaried, with shifts from wetter fen to drier, forested bog communities during the Holocene Thermal Maximum (HTM). Fires became more severe following the shift to forested bogs, with fire severity peaking after 4000 cal years B.P. rather than during the HTM. Rising fire severity, in turn, was correlated with a significant decrease in carbon accumulation from ˜6000 to 2000 cal years B.P. The Medieval Warm Period and Little Ice Age affected vegetation composition and permafrost, further impacting fire and carbon accumulation. Our results indicate that long-term changes in fire and carbon dynamics are mediated by climate-driven changes in vegetation.

Retention of Information as a Function of Lesson Design for Middle School Studies of Wetlands in New Jersey

NASA Astrophysics Data System (ADS)

Parsekian, A.; Cimiluca, C.; Gates, A. E.; Calderon, I.

2010-12-01

Considering the breadth of innovative teaching strategies available, it is helpful to identify which will be best suited for a particular subject. With students that have a variety of interests, it is important to engage as many as possible in the lab activity, especially those who might not identify science as their preferred interest. Here we test the retention of information by middle school students after a problem-based learning (PBL) style lesson compared with an investigation where the students were given no role-playing problem. Both lessons were designed around wetlands in New Jersey: the first being a pond-edge ecosystem in a park near the middle school in Newark, NJ that the students are familiar with and the second being small, isolated peat bogs in the Pinelands of southern New Jersey that are the subject of ongoing scientific research. Days after both hands-on lessons, the students were given short, carefully designed multiple choice quizzes that tested the retention of knowledge about each of the learning objectives set forth. Results of the quizzes are nearly normally distributed, indicating a similar average performance. A higher number of students preformed better on the problem-based learning post-quiz suggesting the inclusion of a role playing scenario is useful for engaging the most students in hands-on wetlands laboratory experiments. Future work should test the retention of this type of information over time and explore other teaching strategies. We also present new ideas for an inexpensive hands-on lesson as implemented for the peat bog wetlands example that introduces basic soil science concepts to middle school and high school students.

Contrasting approaches to determine the impact of permafrost thaw on C cycling in northern peatlands

NASA Astrophysics Data System (ADS)

Heffernan, L.; Estop Aragones, C.; Blodau, C.; Olefeldt, D.

2016-12-01

Northern peatlands are a globally significant pool of terrestrial carbon (C) and have acted as a major C sink since the last deglaciation. The peatland complexes found in western Canada are a mosaic of peat plateaus underlain by permafrost interspersed with permafrost free thermokarst bogs. Recent climate change has led to increased rates of thermokarst bog expansion due to permafrost thaw. In order to understand whether permafrost thaw causes net C loss or uptake, we studied both the variation in C stocks and of surface greenhouse gas fluxes along a pair of thermokarst chronosequences located in thick (>6 m) peatlands in the discontinuous permafrost zone of western Canada. Each zone of a chronosequence is characterized by permafrost conditions, including a zone where permafrost is still present (peat plateau), a zone of recent thermokarst development (dominated by Sphagnum riparium and sedges), and a mature thermokarst zone (dominated by Sphagnum fuscum and woody shrubs) where permafrost thaw occurred >50 years ago. Each zone has distinct hydrological conditions, with the recent thermokarst being much wetter. Increased wetness causes increased heat conduction and average July to November soil temperatures at 50, 100, and 200 cm were 1.6, 2.2, and 1.7 °C warmer, respectively, in the recent than in the mature thermokarst zone. This difference likely increases respiration rates at depth substantially. Our study aims to reconcile findings from other sites where investigations of C stock and greenhouse gas emissions have yielded disparate conclusions. By combining C stocks and C emissions along a thaw chronosequence, and highlighting the differences in C cycling between recently and older thawed thermokarst features, this current work aims to reconcile these contrasting views.

Historical records of atmospheric Pb deposition in four Scottish ombrotrophic peat bogs: An isotopic comparison with other records from western Europe and Greenland - article no. GB2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cloy, J.M.; Farmer, J.G.; Graham, M.C.

2008-05-15

Cores collected from ombrotrophic peat bogs in west central, east central, northeast and southwest Scotland were dated (C-14, Pb-210) and analyzed (ICP-OES, ICP-MS) to derive and compare their historical records of atmospheric anthropogenic Pb deposition over the past 2500 years. On the basis of Pb isotopic composition (e. g., Pb-206/Pb-207), clear indications of Pb contamination during the pre-Roman/Roman, post-Roman and medieval periods were attributed to the mining and smelting of Pb ores from Britain and elsewhere in Europe. Between the 17th and early 20th centuries, during the industrial period, the mining and smelting of indigenous Scottish Pb ores were themore » most important sources of anthropogenic Pb deposition at three of the sites. In contrast, at the most southerly site, influences from the use of both British Pb ores and imported Australian Pb ores (in more southern parts of Britain) since the late 19th century were evident. At each of the sites, Australian-Pb-influenced car exhaust emissions (from the 1930s to late 1990s), along with significant contributions from coal combustion (until the late 1960s and onset of the post industrial period), were evident. Atmospheric anthropogenic Pb deposition across Scotland was greatest (similar to 10 to 40 mg m{sup -2} a{sup -1}) between the late 1880s and late 1960s, increasing southward, declining to 0.44 to 5.7 mg m{sup 2} a{sup -1} by the early 2000s.« less

Dynamics of Viral Abundance and Diversity in a Sphagnum-Dominated Peatland: Temporal Fluctuations Prevail Over Habitat.

PubMed

Ballaud, Flore; Dufresne, Alexis; Francez, André-Jean; Colombet, Jonathan; Sime-Ngando, Télesphore; Quaiser, Achim

2015-01-01

Viruses impact microbial activity and carbon cycling in various environments, but their diversity and ecological importance in Sphagnum-peatlands are unknown. Abundances of viral particles and prokaryotes were monitored bi-monthly at a fen and a bog at two different layers of the peat surface. Viral particle abundance ranged from 1.7 x 10(6) to 5.6 x 10(8) particles mL(-1), and did not differ between fen and bog but showed seasonal fluctuations. These fluctuations were positively correlated with prokaryote abundance and dissolved organic carbon, and negatively correlated with water-table height and dissolved oxygen. Using shotgun metagenomics we observed a shift in viral diversity between winter/spring and summer/autumn, indicating a seasonal succession of viral communities, mainly driven by weather-related environmental changes. Based on the seasonal asynchrony between viral and microbial diversity, we hypothesize a seasonal shift in the active microbial communities associated with a shift from lysogenic to lytic lifestyles. Our results suggest that temporal variations of environmental conditions rather than current habitat differences control the dynamics of virus-host interactions in Sphagnum-dominated peatlands.

Gaseous mercury fluxes in peatlands and the potential influence of climate change

NASA Astrophysics Data System (ADS)

Haynes, Kristine M.; Kane, Evan S.; Potvin, Lynette; Lilleskov, Erik A.; Kolka, Randall K.; Mitchell, Carl P. J.

2017-04-01

Climate change has the potential to significantly impact the stability of large stocks of mercury (Hg) stored in peatland systems due to increasing temperatures, altered water table regimes and subsequent shifts in vascular plant communities. However, the Hg exchange dynamics between the atmosphere and peatlands are not well understood. At the PEATcosm Mesocosm Facility in Houghton, Michigan, total gaseous Hg (TGM) fluxes were monitored in a subset of 1-m3 peat monoliths with altered water table positions (high and low) and vascular plant functional groups (sedge only, Ericaceae only or unmanipulated control) above the Sphagnum moss layer. At the SPRUCE bog in north-central Minnesota, TGM fluxes were measured from plots subjected to deep peat soil warming (up to +9 °C above ambient at a depth of 2 m). At PEATcosm, the strongest depositional trend was observed with the Low WT - sedge only treatment mesocosms with a mean TGM flux of -73.7 ± 6.3 ng m-2 d-1, likely due to shuttling of Hg to the peat at depth by aerenchymous tissues. The highest total leaf surface and tissue Hg concentrations were observed with the Ericaceae shrubs. A negative correlation between TGM flux and Ericaceae total leaf surface area suggests an influence of shrubs in controlling Hg exchange through stomatal uptake, surface sorption and potentially, peat shading. Surface peat total Hg concentrations are highest in treatments with greatest deposition suggesting deposition controls Hg accumulation in surface peat. Fluxes in the SPRUCE plots ranged from -45.9 ± 93.8 ng m-2 d-1 prior to the implementation of the deep warming treatments to -1.41 ± 27.1 ng m-2 d-1 once warming targets were achieved at depth and +10.2 ± 44.6 ng m-2 d-1 following prolonged deep soil warming. While these intervals did not differ significantly, a significant positive increase in the slope of the regression between flux and surface temperature was observed across the pre-treatment and warming periods. Shifts in vascular vegetation cover and peat warming as a result of climate change may significantly affect the dynamics of TGM fluxes between peatlands and the atmosphere.

Sources and distribution of trace elements in Estonian peat

NASA Astrophysics Data System (ADS)

Orru, Hans; Orru, Mall

2006-10-01

This paper presents the results of the distribution of trace elements in Estonian mires. Sixty four mires, representative of the different landscape units, were analyzed for the content of 16 trace elements (Cr, Mn, Ni, Cu, Zn, and Pb using AAS; Cd by GF-AAS; Hg by the cold vapour method; and V, Co, As, Sr, Mo, Th, and U by XRF) as well as other peat characteristics (peat type, degree of humification, pH and ash content). The results of the research show that concentrations of trace elements in peat are generally low: V 3.8 ± 0.6, Cr 3.1 ± 0.2, Mn 35.1 ± 2.7, Co 0.50 ± 0.05, Ni 3.7 ± 0.2, Cu 4.4 ± 0.3, Zn 10.0 ± 0.7, As 2.4 ± 0.3, Sr 21.9 ± 0.9, Mo 1.2 ± 0.2, Cd 0.12 ± 0.01, Hg 0.05 ± 0.01, Pb 3.3 ± 0.2, Th 0.47 ± 0.05, U 1.3 ± 0.2 μg g - 1 and S 0.25 ± 0.02%. Statistical analyses on these large database showed that Co has the highest positive correlations with many elements and ash content. As, Ni, Mo, ash content and pH are also significantly correlated. The lowest abundance of most trace elements was recorded in mires fed only by precipitation (ombrotrophic), and the highest in mires fed by groundwater and springs (minerotrophic), which are situated in the flood plains of river valleys. Concentrations usually differ between the superficial, middle and bottom peat layers, but the significance decreases depending on the type of mire in the following order: transitional mires - raised bogs - fens. Differences among mire types are highest for the superficial but not significant for the basal peat layers. The use of peat with high concentrations of trace elements in agriculture, horticulture, as fuel, for water purification etc., may pose a risk for humans: via the food chain, through inhalation, drinking water etc.

Pollen-based reconstruction of Holocene climate variability in the Eifel region evaluated with stable isotopes

NASA Astrophysics Data System (ADS)

Kühl, Norbert; Moschen, Robert; Wagner, Stefanie

2010-05-01

Pollen as well as stable isotopes have great potential as climate proxy data. While variability in these proxy data is frequently assumed to reflect climate variability, other factors than climate, including human impact and statistical noise, can often not be excluded as primary cause for the observed variability. Multiproxy studies offer the opportunity to test different drivers by providing different lines of evidence for environmental change such as climate variability and human impact. In this multiproxy study we use pollen and peat humification to evaluate to which extent stable oxygen and carbon isotope series from the peat bog "Dürres Maar" reflect human impact rather than climate variability. For times before strong anthropogenic vegetation change, isotope series from Dürres Maar were used to validate quantitative reconstructions based on pollen. Our study site is the kettle hole peat bog "Dürres Maar" in the Eifel low mountain range, Germany (450m asl), which grew 12m during the last 10,000 years. Pollen was analysed with a sum of at least 1000 terrestrial pollen grains throughout the profile to minimize statistical effects on the reconstructions. A recently developed probabilistic indicator taxa method ("pdf-method") was used for the quantitative climate estimates (January and July temperature) based on pollen. For isotope analysis, attention was given to use monospecific Sphagnum leaves whenever possible, reducing the potential of a species effect and any potential artefact that can originate from selective degradation of different morphological parts of Sphagnum plants (Moschen et al., 2009). Pollen at "Dürres Maar" reflect the variable and partly strong human impact on vegetation during the last 4000 years. Stable isotope time series were apparently not influenced by human impact at this site. This highlights the potential of stable isotope investigations from peat for climatic interpretation, because stable isotope series from lacustrine sediments might strongly react to anthropogenic deforestation, as carbon isotope time series from the adjacent Lake Holzmaar suggest. Reconstructions based on pollen with the pdf-method are robust to the human impact during the last 4000 years, but do not reproduce the fine scale climate variability that can be derived from the stable isotope series (Kühl et al., in press). In contrast, reconstructions on the basis of pollen data show relatively pronounced climate variability (here: January temperature) during the Mid-Holocene, which is known from many other European records. The oxygen isotope time series as available now indicate that at least some of the observed variability indeed reflects climate variability. However, stable carbon isotopes show little concordance. At this stage our results point in the direction that 1) the isotopic composition might reflect a shift in influencing factors during the Holocene, 2) climate trends can robustly be reconstructed with the pdf method and 3) fine scale climate variability can potentially be reconstructed using the pdf-method, given that climate sensitive taxa at their distribution limit are present. The latter two conclusions are of particular importance for the reconstruction of climatic trends and variability of interglacials older than the Holocene, when sites are rare and pollen is often the only suitable proxy in terrestrial records. Kühl, N., Moschen, R., Wagner, S., Brewer, S., Peyron, O., in press. A multiproxy record of Late Holocene natural and anthropogenic environmental change from the Sphagnum peat bog Dürres Maar, Germany: implications for quantitative climate reconstructions based on pollen. J. Quat. Sci., DOI: 10.1002/jqs.1342. Available online. Moschen, R., Kühl, N., Rehberger, I., Lücke, A., 2009. Stable carbon and oxygen isotopes in sub-fossil Sphagnum: Assessment of their applicability for palaeoclimatology. Chemical Geology 259, 262-272.

The effect of a reciprocal peat transplant between two contrasting Central European sites on C cycling and C isotope ratios

NASA Astrophysics Data System (ADS)

Novak, M.; Zemanova, L.; Buzek, F.; Jackova, I.; Adamova, M.; Komarek, A.; Vile, M. A.; Kelman Wieder, R.; Stepanova, M.

2010-03-01

An 18-month reciprocal peat transplant experiment was conducted between two peatlands in the Czech Republic. Both sites were 100% Sphagnum-covered, with no vascular plants, and no hummocks and hollows. Atmospheric depositions of sulfur were up to 10 times higher at the northern site Velke jerabi jezero (VJJ), compared to the southern site Cervene blato (CB). Forty-cm deep peat cores, 10-cm in diameter, were used as transplants and controls in five replicates. Our objective was to evaluate whether CO2 and CH4 emissions from Sphagnum peat bogs are governed mainly by organic matter quality in the substrate, or by environmental conditions. Emission rates and δ13C values of CO2 and CH4 were measured in the laboratory at time t=18 months. All measured parameters converged to those of the host site, indicating that, at least in the short-term perspective, environmental conditions were a more important control of greenhouse gas emissions than organic carbon quality in the substrate. Since sulfate reducers outcompete methanogens, we hypothesized that the S-polluted site VJJ should have lower methane emissions than CB. In fact, the opposite was true, with significantly (p<0.01) higher methane emissions from VJJ. Additionally, as a first step in an effort to link C isotope composition of emitted gases and residual peat substrate, we determined whether multiple vertical δ13C profiles in peat agree. A high degree of within-site homogeneity in δ13C was found. When a specific vertical δ13C trend was seen in one peat core, the same trend was also seen in all the remaining peat cores from the wetland. The δ13C value increased downcore at both CB and VJJ. At VJJ, however, 20 cm below surface, a reversal to lower δ13C downcore was seen. Based on 210Pb dating, peat at 20-cm depth at VJJ was only 15 years old. Increasing δ13C values in VJJ peat accumulated between 1880-1990 could not be caused by assimilation of atmospheric CO2 gradually enriched in the light isotope 12C due to fossil fuel burning. Rather they were a result of a combination of isotope fractionations accompanying assimilation and mineralization of Sphagnum C. These isotope fractionations may record information about past changes in C storage in wetlands.

Southern Hemisphere bog persists as a strong carbon sink during droughts

NASA Astrophysics Data System (ADS)

Goodrich, Jordan P.; Campbell, David I.; Schipper, Louis A.

2017-10-01

Peatland ecosystems have been important global carbon sinks throughout the Holocene. Most of the research on peatland carbon budgets and effects of variable weather conditions has been done in Northern Hemisphere Sphagnum-dominated systems. Given their importance in other geographic and climatic regions, a better understanding of peatland carbon dynamics is needed across the spectrum of global peatland types. In New Zealand, much of the historic peatland area has been drained for agriculture but little is known about rates of carbon exchange and storage in unaltered peatland remnants that are dominated by the jointed wire rush, Empodisma robustum. We used eddy covariance to measure ecosystem-scale CO2 and CH4 fluxes and a water balance approach to estimate the sub-surface flux of dissolved organic carbon from the largest remaining raised peat bog in New Zealand, Kopuatai bog. The net ecosystem carbon balance (NECB) was estimated over four years, which included two drought summers, a relatively wet summer, and a meteorologically average summer. In all measurement years, the bog was a substantial sink for carbon, ranging from 134.7 to 216.9 gC m-2 yr-1, owing to the large annual net ecosystem production (161.8 to 244.9 gCO2-C m-2 yr-1). Annual methane fluxes were large relative to most Northern Hemisphere peatlands (14.2 to 21.9 gCH4-C m-2 yr-1), although summer and autumn emissions were highly sensitive to dry conditions, leading to very predictable seasonality according to water table position. The annual flux of dissolved organic carbon was similar in magnitude to methane emissions but less variable, ranging from 11.7 to 12.8 gC m-2 yr-1. Dry conditions experienced during late summer droughts led to significant reductions in annual carbon storage, which resulted nearly equally from enhanced ecosystem respiration due to lowered water tables and increased temperatures, and from reduced gross primary production due to vapor pressure deficit-related stresses to the vegetation. However, the net C uptake of Kopuatai bog during drought years was large relative to even the maximum reported NECB from Northern Hemisphere bogs. Furthermore, global warming potential fluxes indicated the bog was a strong sink for greenhouse gases in all years despite the relatively large annual methane emissions. Our results suggest that adaptations of E. robustum to dry conditions lead to a resilient peatland drought response of the NECB.

Geophysical imaging and thermal modeling of subsurface morphology and thaw evolution of discontinuous permafrost

NASA Astrophysics Data System (ADS)

McClymont, Alastair F.; Hayashi, Masaki; Bentley, Laurence R.; Christensen, Brendan S.

2013-09-01

our current understanding of permafrost thaw in subarctic regions in response to rising air temperatures, little is known about the subsurface geometry and distribution of discontinuous permafrost bodies in peat-covered, wetland-dominated terrains and their responses to rising temperature. Using electrical resistivity tomography, ground-penetrating radar profiling, and thermal-conduction modeling, we show how the land cover distributions influence thawing of discontinuous permafrost at a study site in the Northwest Territories, Canada. Permafrost bodies in this region occur under forested peat plateaus and have thicknesses of 5-13 m. Our geophysical data reveal different stages of thaw resulting from disturbances within the active layer: from widening and deepening of differential thaw features under small frost-table depressions to complete thaw of permafrost under an isolated bog. By using two-dimensional geometric constraints derived from our geophysics profiles and meteorological data, we model seasonal and interannual changes to permafrost distribution in response to contemporary climatic conditions and changes in land cover. Modeling results show that in this environment (1) differences in land cover have a strong influence on subsurface thermal gradients such that lateral thaw dominates over vertical thaw and (2) in accordance with field observations, thaw-induced subsidence and flooding at the lateral margins of peat plateaus represents a positive feedback that leads to enhanced warming along the margins of peat plateaus and subsequent lateral heat conduction. Based on our analysis, we suggest that subsurface energy transfer processes (and feedbacks) at scales of 1-100 m have a strong influence on overall permafrost degradation rates at much larger scales.

Water resources of the Snake River watershed, east-central Minnesota

USGS Publications Warehouse

Lindholm, Gerald F.; Helgesen, J.O.; Broussard, W.L.; Ericson, D.W.

1974-01-01

The Snake River, which drains an area of about 1,030 square miles, originates in an extensive area of peat bogs in the northern part of the watershed. It flows southward across gently rolling glacial terrain in which the major relief is near the river. Near the southern boundary of the watershed, the Snake River turns eastward to its confluence with the St. Croix River. The northwest half of the watershed is heavily forested, whereas much of the southeast half has been cleared. The largest communities in the watershed, Mora and Pine City, had 1970 populations of 2,582 and 2,143, respectively.

Carbon-14 in methane sources and in atmospheric methane - The contribution from fossil carbon

NASA Technical Reports Server (NTRS)

Wahlen, M.; Tanaka, N.; Henry, R.; Deck, B.; Zeglen, J.

1989-01-01

Measurements of carbon-14 in small samples of methane from major biogenic sources, from biomass burning, and in clean air samples from both the Northern and Southern hemispheres reveal that methane from ruminants contains contemporary carbon, whereas that from wetlands, peat bogs, rice fields, and tundra, is somewhat depleted in carbon-14. Atmospheric (C-14)H4 seems to have increased from 1986 to 1987, and levels at the end of 1987 were 123.3 + or - 0.8 percent modern carbon in the Northern Hemisphere and 120.0 + or - 0.7 percent modern carbon in the Southern Hemisphere.

Holocene climate dynamics in the Eastern Italian Alps: a multi-proxy study from ice and peat bogs

NASA Astrophysics Data System (ADS)

Poto, Luisa; Gabrieli, Jacopo; Segnana, Michela; Festi, Daniela; Oeggl, Klaus; Barbante, Carlo

2014-05-01

The Eastern Italian Alps are located near one of the areas in the world with some of the longest records of extreme environmental use by human activity. In this area, paleo-climate studies are hampered by the lack of high-resolution multi-proxy records with adequate chronological control. With this project, we propose to reconstruct Holocene climatic and environmental variations in the Eastern Italian Alps using terrestrial and glaciological archives. We aim to study the characteristics of different climate stages in this sector of the Alps using an ice core drilled on the top of the Ortles glacier (46°30' N, 10°32 E, 3850 m a.s.l.) and ombrotrophic peat bog records from the Dolomites (Danta di Cadore, 46°34' N, 12°33 E, 1400 m a.s.l. and Coltrondo 46°39'28.37''N 12°26'59.17''E, 1800 m a.s.l., Belluno province). The study of global climatic change require a holistic and multi-proxy approach to better understand several complex and often non-linear relationships. In the Italian Alps our study on peat cores represents the first attempt where a multi-proxy approach is applied, and here we report our first results. A 7.0 m peat sequence was extracted in Danta di Cadore. The depth-age scale, based upon independent 14C and 210Pb dates and modeled with the Clam method (Blaauw, 2010), demonstrates that the archive covers more than 13,200 years (cal BP). We determined physical proprieties, Ca and Ti trends, pore water pH, conductivity, and Ca/Mg ratios to identify changes in trophic conditions. The results confirm that the uppermost 400 cm are composed of ombrotrophic peat representing the longest Eastern Alpine ombrotrophic record yet obtained, covering the last 7,000 years. The oldest radiocarbon age (13,200 years cal BP) provides evidence that, during the Bölling-Alleröd interstadial, the upper part of the Piave Glacier was ice-free up to 1400 m a.s.l.. At that time pollen assemblages show that a conifer forest characterized the local vegetation. This forest was then affected by the climatic cooling of the Younger Dryas, which caused an opening of the vegetation. The climatic amelioration occurring at the onset of the Holocene favored the local expansion of warmth-demanding species. X-ray Fluorescence Core Scanner (XRF-CS) analysis was applied for the first time on Eastern Alpine peat sequences. XRF-CS signals were calibrated with ICP-MS, showing very high correlation and demonstrating that the XRF-CS technique provides reliable quantitative data. Results provide information about geochemical processes occurring in the bog. The impact of mining activity was also evaluated. Concentration levels and enrichment factors (EFs) of several trace elements such as Pb, Ag and Cd correspond to the historical data about mining activities in the Cadore region. Lead isotopes ratios were measured to identify natural and anthropogenic sources of Pb emissions. Results show an increase of Pb deriving from fuel combustion over the last decades that gradually overlie the impacts of mining activity. The decreasing 206Pb/207Pb trend reached its minimum value of 1.153 in the 1990s and then increased again. In these years, Italy started to follow EU rules to limit global pollutants in the atmosphere, and finally banned leaded fuels in 2002. Both 206Pb/207Pb ratio and Pb fluxes show a particular event between 1975 and 1980: this behavior is characteristic of the ILE (Isotopic Lead Experiment), a large-scale isotopic tracer experiment which was carried out in the Piedmont region (N-W Italy). This multi-proxy approach that integrates, using new chronological insights, chemical physical and biological features of the core, improves our understanding of Eastern Alpine Holocene climate, helping to delineate biotic and abiotic responses to climate dynamics during the present interglacial. Blaauw, M. 2010. Methods and code for 'classical' age modeling of radiocarbon sequences. Quarternary Geochronology, 5: 512-518.

Biochemical evidence for minimal vegetation change in peatlands of the West Siberian Lowland during the Medieval Climate Anomaly and Little Ice Age

NASA Astrophysics Data System (ADS)

Philben, Michael; Kaiser, Karl; Benner, Ronald

2014-05-01

Peatland vegetation is controlled primarily by the depth of the water table, making peat paleovegetation a useful climate archive. We applied a biochemical approach to quantitatively estimate the plant sources of peat carbon based on (1) neutral sugar compositions of Sphagnum, vascular plants, and lichens and (2) lignin phenol compositions of vascular plants. We used these biochemical indices to characterize vegetation change over the last 2000 years in four peat cores from the West Siberian Lowland (Russia) to investigate climate change during the Medieval Climate Anomaly and Little Ice Age. The vegetation was dominated by Sphagnum in all four cores, but was punctuated by several rapid but transient transitions to vascular plant dominance in the two cores from the southern West Siberian Lowland (<60°N latitude). Lichen contributions were evident at the end of the Medieval Climate Anomaly and during the Little Ice Age in the two cores from northern West Siberian Lowland (>60°N), possibly indicating permafrost development. However, there was no evidence for sustained vegetation change in response to either climatic event in cores from southern West Siberian Lowland. This suggests that these climatic events were relatively mild in the southern West Siberian Lowland, although the sensitivity of bog plant communities to climate change remains poorly understood.

Cultivating Uncultured Bacteria from Northern Wetlands: Knowledge Gained and Remaining Gaps

PubMed Central

Dedysh, Svetlana N.

2011-01-01

Northern wetlands play a key role in the global carbon budget, particularly in the budgets of the greenhouse gas methane. These ecosystems also determine the hydrology of northern rivers and represent one of the largest reservoirs of fresh water in the Northern Hemisphere. Sphagnum-dominated peat bogs and fens are the most extensive types of northern wetlands. In comparison to many other terrestrial ecosystems, the bacterial diversity in Sphagnum-dominated wetlands remains largely unexplored. As demonstrated by cultivation-independent studies, a large proportion of the indigenous microbial communities in these acidic, cold, nutrient-poor, and water-saturated environments is composed of as-yet-uncultivated bacteria with unknown physiologies. Most of them are slow-growing, oligotrophic microorganisms that are difficult to isolate and to manipulate in the laboratory. Yet, significant breakthroughs in cultivation of these elusive organisms have been made during the last decade. This article describes the major prerequisites for successful cultivation of peat-inhabiting microbes, gives an overview of the currently captured bacterial diversity from northern wetlands and discusses the unique characteristics of the newly discovered organisms. PMID:21954394

Emissions of sulfur gases from wetlands

NASA Technical Reports Server (NTRS)

Hines, Mark E.

1992-01-01

Data on the emissions of sulfur gases from marine and freshwater wetlands are summarized with respect to wetland vegetation type and possible formation mechanisms. The current data base is largest for salt marshes inhabited by Spartina alterniflora. Both dimethyl sulfide (DMS) and hydrogen sulfide (H2S) dominate emissions from salt marshes, with lesser quantities of methyl mercaptan (MeSH), carbonyl sulfide (COS), carbon disulfide (CS2) and dimethyl disulfide (DMDS) being emitted. High emission rates of DMS are associated with vegetation that produces the DMS precursor dimethylsulfonionpropionate (DMSP). Although large quantities of H2S are produced in marshes, only a small percentage escapes to the atmosphere. High latitude marshes emit less sulfur gases than temperate ones, but DMS still dominates. Mangrove-inhabited wetlands also emit less sulfur than temperate S. alterniflora marshes. Few data are available on sulfur gas emissions from freshwater wetlands. In most instances, sulfur emissions from temperate freshwater sites are low. However, some temperate and subtropical freshwater sites are similar in magnitude to those from marine wetlands which do not contain vegetation that produces DMSP. Emissions are low in Alaskan tundra but may be considerably higher in some bogs and fens.

The complex relationships between methane emissions and water table at an ombrotrophic bog

NASA Astrophysics Data System (ADS)

Humphreys, Elyn; Roulet, Nigel; Moore, Tim

2017-04-01

Broad spatial and temporal variations in methane emissions from peatlands have been related to many variables including water table position, temperature and vegetation characteristics and functioning. In general, wetter peatlands tend to have greater methane emissions. However, over shorter periods of time and space, the relationship between water table and methane emissions can reverse, show hysteresis or be absent entirely. These relationships are investigated at the Mer Bleue Bog, a temperate ombrotrophic bog near Ottawa, Canada. Six years of concurrent growing season eddy covariance and automated chamber fluxes reveal the expected broad patterns. During the wettest growing season, the water table remained within 40 cm of the bog's hummock surfaces. Methane emissions were upwards of 20 to 45 mg C m-2 d-1 and exceeded the emission rates from two drier growing seasons which saw periods where the water table dropped to nearly 80 cm below the hummock surface. In those periods, methane emission rates declined to about 5 mg C m-2 d-1 or less. Lawn plots with aerenchymatous Eriophorum vegetation and high water tables had greatest emissions (exceeding 200 mg C m-2 d-1) compared to hummock plots vegetated by ericaceous shrubs, which had emissions rates similar to those measured by eddy covariance. However, within a growing season, hysteresis and inverse relationships between water table and methane emissions were observed at both ecosystem and chamber plot scales. These included periods between rainfall events where methane emissions increased while the water table deepened. The potential roles of methane production, consumption, storage and transport processes on these patterns will be discussed.

Will blocking historical drainage ditches increase carbon sequestration in upland blanket mires of Southwest England?

NASA Astrophysics Data System (ADS)

Le Feuvre, N.; Hartley, I.; Anderson, K.; Luscombe, D.; Grand-Clement, E.; Smith, D.; Brazier, R.

2012-04-01

Peat soils in the United Kingdom are estimated to store a minimum of 3,121Mt C (Lindsay, 2010). Despite being such a large carbon store the annual imbalance between uptake and release is small and susceptible to change in response to land management, atmospheric deposition and climate change. The upland blanket mires of Southwest England have been subject to extensive drainage and are particularly vulnerable to climate change as they lie at the lower edge of the peatland climatic envelope. The Mires-on-the-Moors project, funded by South West Water will restore over 2000 hectares of drained mire by April 2015. Herein, we question whether this restoration, which will block historical drainage ditches will allow the blanket bogs of Exmoor and Dartmoor National Parks to recover their ecohydrological functionality. We hypothesise that such mire restoration will increase the resilience of these ecosystems to climate change and will return these upland mires to peat forming/carbon sequestering systems. A method is proposed which aims to understand the processes driving gaseous carbon exchange and peat formation in an upland blanket bog and quantifies the effect restoration has on these processes. We propose to measure the spatial variation in gas fluxes with respect to structural features of the mire; drainage ditches and nanotopes. The role of vegetation; the community composition, phenology and health will be explored as well as environmental variables such as water table depths, temperature and photosynthetically active radiation. Importantly, the experiment will partition below ground respiration to assess the environmental controls and effect of restoration on autotrophic and heterotrophic respiration separately. Unusually, it will be possible to collect both pre- and post-restoration data for two experimental sites with existing intensive hydrological monitoring (baseline monitoring of water table depths at 15 minute timesteps has been in place for > 1 year at ca. 160 locations across two experimental catchments on Exmoor). Remote sensing of vegetation structure (using both airborne LiDAR and ground-based laser scanning tools) alongside geospatial modelling will enable the effects of restoration on carbon storage to be modelled from headwater catchment to moorland scales. Lindsay, R. (2010) Peatbogs and Carbon: A Critical Synthesis. University of East London, London.

Synchronicity of the East Asian Summer Monsoon variability and Northern Hemisphere climate change since the last deglaciation

NASA Astrophysics Data System (ADS)

Shinozaki, T.; Uchida, M.; Minoura, K.; Kondo, M.; Rella, S. F.; Shibata, Y.

2011-06-01

Understanding of the mechanism of the East Asian Summer Monsoon (EASM) is required for the prediction of climate change in East Asia in a scenario of modern global warming. In this study, we present high-resolution climate records from peat sediments in Northeast Japan to reconstruct the EASM variability based on peat bulk cellulose δ13C since the last deglaciation. We used a 8.8 m long peat sediment core collected from the Tashiro Bog, Northeast Japan. Based on 42 14C measurements, the core bottom reaches ~15.5 ka. δ13C, accumulation rate and accumulation flux time-series correlate well to Greenland ice core δ18O variability, suggesting that the climate record in Northeast Japan is linked to global climate changes. The δ13C record at Tashiro Bog and other paleo-EASM records at Northeast and Southern China consistently demonstrate that hydrological environments were spatially different in mid-high and mid-low latitude regions over the last 15.5 kyr. During global cooling (warming) periods, mid-high and mid-low latitude regions were characterized by wet (dry) and dry (wet) environments, respectively. We suggest that these climatic patterns are related to the migration of the EASM-related rain belt during global climate changes, as a consequence of variations in intensity and location of both the Intertropical Convergence Zone (ITCZ) and the Western Pacific Subtropical High (STH). The location of the rain belt largely influences the East Asian hydrological environment. Our δ13C time-series are characterized by a 1230 yr throughout the Holocene and a 680 yr periodicity during the early Holocene. The 1230 yr periodicity is in agreement with North Atlantic ice-rafted debris (IRD) events, suggesting a teleconnection between the Northeast Japan and the North Atlantic during the Holocene. In addition, it is the first evidence that the Bond events were recorded in terrestrial sediment in Japan. On the other hand, the 680 yr periodicity between 10.0 and 8.0 kyr is consistent with a prominent 649 yr solar activity cycle, suggesting that solar activity affected EASM precipitation during the Hypsithermal, when orbital-scale solar insolation was at a maximum in the Northern Hemisphere.

Microbial Formation of Dimethyl Sulfide in Anoxic Sphagnum Peat

PubMed Central

Kiene, R. P.; Hines, M. E.

1995-01-01

Peat bogs dominated by Sphagnum spp. have relatively high areal rates of dimethyl sulfide (DMS) emission to the atmosphere. DMS was produced in anoxic slurries of Sphagnum peat with a linear time course and with an average rate of 40.4 (range, 22.0 to 68.6) nmol per liter of slurry (middot) day(sup-1) observed in nine batches of slurry. Methanethiol (MeSH) was produced at roughly similar rates over the typical 4- to 8-day incubations. DMS and MeSH production in these acidic (pH 4.2 to 4.6) peats were biological, as they were stopped completely by autoclaving and inhibited strongly by addition of antibiotics and 500 (mu)M chloroform. Endogenous DMS production may be due to the degradation of S-methyl-methionine, dimethyl sulfoxide, or methoxyaromatic compounds (e.g., syringic acid), each of which stimulated DMS formation when added at 5 to 10 (mu)M concentrations. However, on the basis of the high rates of thiol (MeSH and ethanethiol) methylation activity that we observed and the availability of endogenous MeSH, we suggest that methylation of MeSH is the major pathway leading to DMS formation in anaerobic peat. Solid-phase adsorption of MeSH plays a key role in its availability for biomethylation reactions. Additions of acetate (1.5 mM) or compounds which could cause acetate to accumulate (e.g., glucose, alanine, and 2-bromoethanesulfonate) suppressed DMS formation. It is likely that acetogenic bacteria are involved in DMS formation, but our data are insufficient to allow firm conclusions about the metabolic pathways or organisms involved. Our observations are the first which point to the methylation of MeSH as the major mechanism for endogenous DMS production in any environment. The rates of net DMS production observed are sufficient to explain the relatively high fluxes of DMS emitted to the atmosphere from Sphagnum sp.-dominated wetlands. PMID:16535080

High Throughput Sequencing to Detect Differences in Methanotrophic Methylococcaceae and Methylocystaceae in Surface Peat, Forest Soil, and Sphagnum Moss in Cranesville Swamp Preserve, West Virginia, USA

PubMed Central

Lau, Evan; Nolan, Edward J.; Dillard, Zachary W.; Dague, Ryan D.; Semple, Amanda L.; Wentzell, Wendi L.

2015-01-01

Northern temperate forest soils and Sphagnum-dominated peatlands are a major source and sink of methane. In these ecosystems, methane is mainly oxidized by aerobic methanotrophic bacteria, which are typically found in aerated forest soils, surface peat, and Sphagnum moss. We contrasted methanotrophic bacterial diversity and abundances from the (i) organic horizon of forest soil; (ii) surface peat; and (iii) submerged Sphagnum moss from Cranesville Swamp Preserve, West Virginia, using multiplex sequencing of bacterial 16S rRNA (V3 region) gene amplicons. From ~1 million reads, >50,000 unique OTUs (Operational Taxonomic Units), 29 and 34 unique sequences were detected in the Methylococcaceae and Methylocystaceae, respectively, and 24 potential methanotrophs in the Beijerinckiaceae were also identified. Methylacidiphilum-like methanotrophs were not detected. Proteobacterial methanotrophic bacteria constitute <2% of microbiota in these environments, with the Methylocystaceae one to two orders of magnitude more abundant than the Methylococcaceae in all environments sampled. The Methylococcaceae are also less diverse in forest soil compared to the other two habitats. Nonmetric multidimensional scaling analyses indicated that the majority of methanotrophs from the Methylococcaceae and Methylocystaceae tend to occur in one habitat only (peat or Sphagnum moss) or co-occurred in both Sphagnum moss and peat. This study provides insights into the structure of methanotrophic communities in relationship to habitat type, and suggests that peat and Sphagnum moss can influence methanotroph community structure and biogeography. PMID:27682082

High soil solution carbon und nitrogen concentrations in a drained Atlantic bog are reduced to natural levels by 10 yr of rewetting

NASA Astrophysics Data System (ADS)

Frank, S.; Tiemeyer, B.; Gelbrecht, J.; Freibauer, A.

2013-10-01

Artificial drainage of peatlands causes dramatic changes in the release of greenhouse gases and in the export of dissolved carbon (C) and nutrients to downstream ecosystems. Rewetting anthropogenically altered peatlands offers a possibility to reduce nitrogen (N) and C losses. In this study, we investigate the impact of drainage and rewetting on the cycling of dissolved C and N as well as on dissolved gases over a period of 1 yr and 4 month, respectively. The peeper technique was used to receive a high vertical sampling resolution. Within one Atlantic bog complex a near natural site, two drained grasslands sites with different mean water table positions, and a former peat cutting area rewetted 10 yr ago were chosen. Our results clearly indicate that drainage increased the concentration of dissolved organic carbon (DOC), ammonia, nitrate and dissolved organic nitrogen (DON) compared to the near natural site. Drainage depth further determined the release and therefore the concentration level of DOC and N species, but the biochemical cycling and therefore dissolved organic matter (DOM) quality and N species composition were unaffected. Thus, especially deep drainage can cause high DOC losses. In general, DOM at drained sites was enriched in aromatic moieties as indicated by SUVA280 and showed a higher degradation status (lower DOC to DON ratio) compared to the near natural site. At the drained sites, equal C to N ratios of uppermost peat layer and DOC to DON ratio of DOM in soil solution suggest that the uppermost degraded peat layer is the main source of DOM. Nearly constant DOC to DON ratios and SUVA280 values with depth furthermore indicated that DOM moving downwards through the drained sites remained largely unchanged. DON and ammonia contributed most to the total dissolved nitrogen (TN). The subsoil concentrations of nitrate were negligible due to strong decline in nitrate around mean water table depth. Methane production during the winter months at the drained sites moved downwards to areas which were mostly water saturated over the whole year (>40 cm). Above these depths, the recovery of the water table in winter months led to the production of nitrous oxide around mean water table depth at drained sites. 10 yr after rewetting, the DOM quality (DOC to DON ratio and SUVA280) and quantity were comparable to the near natural site, indicating the re-establishment of mostly pristine biochemical processes under continuously water logged conditions. The only differences occur in elevated dissolved methane and ammonia concentrations reflecting the former disturbance by drainage and peat extraction. Rewetting via polder technique seems to be an appropriate way to revitalize peatlands on longer timescales and to improve the water quality of downstream water bodies.

Transport and thermodynamics constrain belowground carbon turnover in a northern peatland

NASA Astrophysics Data System (ADS)

Beer, Julia; Blodau, Christian

2007-06-01

Rates of anaerobic respiration are of central importance for the long-term burial of carbon (C) in peatlands, which are a relevant sink in the global C cycle. To identify constraints on anaerobic peat decomposition, we determined detailed concentration depth profiles of decomposition end-products, i.e. methane (CH 4) and dissolved inorganic carbon (DIC), along with concentrations of relevant decomposition intermediates at an ombrotrophic Canadian peat bog. The magnitude of in situ net production rates of DIC and CH 4 was estimated by inverse pore-water modeling. Vertical transport in the peat was slow and dominated by diffusion leading to the buildup of DIC and CH 4 with depth (5500 μmol L -1 DIC, 500 μmol L -1 CH 4). Highest DIC and CH 4 production rates occurred close to the water table (decomposition constant kd ˜ 10 -3-10 -4 a -1) or in some distinct zones at depth ( kd ˜ 10 -4 a -1). Deeper into the peat, decomposition proceeded very slowly at about kd = 10 -7 a -1. This pattern could be related to thermodynamic and transport constraints. The accumulation of metabolic end-products diminished in situ energy yields of acetoclastic methanogenesis to the threshold for microbially mediated processes (-20 to -25 kJ mol -1 CH 4). The methanogenic precursor acetate also accumulated (150 μmol L -1). In line with these findings, CH 4 was formed by hydrogenotrophic methanogenesis at Gibbs free energies of -35 to -40 kJ mol -1 CH 4. This was indicated by an isotopic fractionation α-CH of 1.069-1.079. Fermentative degradation of acetate, propionate and butyrate attained Gibbs free energies close to 0 kJ mol -1 substrate. Although methanogenesis was apparently limited by some other factor in some peat layers, transport and thermodynamic constraints likely impeded respiratory processes in the deeper peat. Constraints on the removal of DIC and CH 4 may thus slow decomposition and contribute to the sustained burial of C in northern peatlands.

The temperature characteristics of biological active period of the peat soils of Bakchar swamp

NASA Astrophysics Data System (ADS)

Kiselev, M. V.; Dyukarev, E. A.; Voropay, N. N.

2018-01-01

The results of the study of the peculiarities of the temperature regime in the five basic ecosystems of oligotrophic bogs in the south taiga zone of Western Siberia in 2011-2016 are presented. The soil temperature regime was studied using the atmospheric-soil measuring complex at different depths from surface to 240 cm. All sites were divided into two groups according the bog water level: flooded sites (hollow and open fen) and drained sites (ridge, tall and low ryam). Waterlogged sites are better warmed in the summer period, and slowly freeze in the winter period. The analysis of the annual cycle of temperature showed that the maximum surface temperature is observed in July. The minimum temperature on the surface observed in February or January. The greatest temperature gradient was recorded in the upper 2 cm layer. The gradient at the open fen was -2 °C·cm-1 in February and 1.1 °C·cm-1 in October. The peak of formation of the seasonally frozen layer occurs at the end of autumn, beginning of winter. The degradation of the seasonally frozen layer was observed both from top and bottom, but degradation from the top is faster.

Wetlands in The Netherlands and New Zealand: optimising biodiversity and carbon sequestration during urbanisation.

PubMed

van Roon, Marjorie R

2012-06-30

The halting of biodiversity decline of wetlands necessitates ecosystem protection, restoration and re-creation of all wetland types preferably in all suitable landscapes. As peat wetlands (bogs and fens) are superior as carbon stores, and because of their rarity they have a higher biodiversity value relative to other wetland types, they need to be prioritised for protection and restoration. The hydrological, pH, and nutrient conditions essential to each type of wetland that need to be understood and provided for during development are discussed for The Netherlands' and New Zealand. Case studies describe freshwater wetland management and challenges during urbanisation in the Stad van de Zon and Blauwestad in The Netherlands, and in the Styx valley and Pegasus in Christchurch, New Zealand. A summary of the history of urbanisation and wetland destruction, and of biodiversity management for each country provides a context for the case studies. These case studies demonstrate the degree to which the relative values of bogs, fens and swamps, with respect to biodiversity and carbon sequestration, are understood and managed using diverse protection measures, within the boundaries of new urban developments and in adjacent ecological corridors. Copyright © 2012 Elsevier Ltd. All rights reserved.

Factors affecting re-vegetation dynamics of experimentally restored extracted peatland in Estonia.

PubMed

Karofeld, Edgar; Müür, Mari; Vellak, Kai

2016-07-01

Increasing human activity continues to threaten peatlands, and as the area of natural mires declines, our obligation is to restore their ecosystem functions. Several restoration strategies have been developed for restoration of extracted peatlands, including "The moss layer transfer method", which was initiated on the Tässi extracted peatland in central Estonia in May 2012. Three-year study shows that despite the fluctuating water table, rainfall events can compensate for the insufficient moisture for mosses. Total plant cover on the restoration area attained 70 %, of which ~60 % is comprised of target species-Sphagnum mosses. From restoration treatments, spreading of plant fragments had a significant positive effect on the cover of bryophyte and vascular plants. Higher water table combined with higher plant fragments spreading density and stripping of oxidised peat layer affected positively the cover of targeted Sphagnum species. The species composition in the restoration area became similar to that in the donor site in a natural bog. Based on results, it was concluded that the method approved for restoration in North America gives good results also in the restoration of extracted peatland towards re-establishment of bog vegetation under northern European conditions.

Agricultural management impact on physical and chemical functions of European peat soils.

NASA Astrophysics Data System (ADS)

Piayda, Arndt; Tiemeyer, Bärbel; Dettmann, Ullrich; Bechtold, Michel; Buschmann, Christoph

2017-04-01

Peat soils offer numerous functions from the global to the local scale: they constitute the biggest terrestrial carbon storage on the globe, form important nutrient filters for catchments and provide hydrological buffer capacities for local ecosystems. Peat soils represent a large share of soils suitable for agriculture in temperate and boreal Europe, pressurized by increasing demands for production. Cultivated peat soils, however, show extreme mineralization rates of the organic substance and turn into hotspots for green house gas emissions, are highly vulnerable to land surface subsidence, soil and water quality deterioration and thus crop failure. The aim of this study is to analyse the impact of past agricultural management on soil physical and chemical functions of peat soils in six European countries. We conducted standardized soil mapping, soil physical/chemical analysis, ground water table monitoring and farm business surveys across 7 to 10 sites in Germany, The Netherlands, Denmark, Estonia, Finland and Sweden. The results show a strong impact of past agricultural management on peat soil functions across Europe. Peat soil under intensive arable land use consistently offer lowest bearing capacities in the upper 10 cm compared to extensive and intensive grassland use, which is a major limiting factor for successful agricultural practice on peat soils. The difference can be explained by root mat stabilization solely, since soil compaction in the upper 25cm is highest under arable land use. A strong decrease of available water capacity and saturated hydraulic conductivity is consequently observed under arable land use, further intensifying hydrological problems like ponding, drought stress and reductions of hydrological buffer capacities frequently present on cultivated peat soils. Soil carbon stocks clearly decrease with increasing land use intensity, showing highest carbon stocks on extensive grassland. This is supported by the degree of decomposition, which is lowest for extensive grass land. Both findings indicate a strong impact of land use intensity and management on soil carbon losses and peat conservation on the European scale. This study provides evidence how functions of peat soils, valuable for successful agricultural production and relevant for climate change mitigation, are impacted by agricultural management.

Alternative soilless media for growing Petunia x hybrida and Impatiens wallerana: physical behavior, effect of fertilization and nitrate losses.

PubMed

Chavez, Walter; Di Benedetto, Adalberto; Civeira, Gabriela; Lavado, Raúl

2008-11-01

The use of alternative soilless media for the production of potted plants requires knowledge of their physical and chemical characteristics to result in the best conditions for plant growth. We investigated the use of alternative soilless media based on river waste and Sphagnun sp. and Carex sp. from Argentinean peatlands on Petuniaxhybrida and Impatiens wallerana production at two fertilization levels (200 and 400mgl(-1)N). River waste or 'temperate peat' is the name given to a material, resulting from the accumulation of aquatic plant residues under an anaerobic subtropical environment, which is dredged from river banks. Our results showed that alternative substrates based on river waste can be used to grow high quality plants. This result was not fully explained on the basis of established methods to evaluate substrate quality. Highly concentrated fertigation solution decreased the substrate quality parameters and plant growth. Nitrate leaching from the alternative substrates containing river waste was lower than the standard peat-based materials, which makes river waste desirable from a sustainable pot production system perspective. River waste and Carex peat are suitable alternatives to Sphagnum peat from the Northern Hemisphere.

Modelling Holocene peatland dynamics with an individual-based dynamic vegetation model

NASA Astrophysics Data System (ADS)

Chaudhary, Nitin; Miller, Paul A.; Smith, Benjamin

2017-05-01

Dynamic global vegetation models (DGVMs) are designed for the study of past, present and future vegetation patterns together with associated biogeochemical cycles and climate feedbacks. However, most DGVMs do not yet have detailed representations of permafrost and non-permafrost peatlands, which are an important store of carbon, particularly at high latitudes. We demonstrate a new implementation of peatland dynamics in a customized Arctic version of the LPJ-GUESS DGVM, simulating the long-term evolution of selected northern peatland ecosystems and assessing the effect of changing climate on peatland carbon balance. Our approach employs a dynamic multi-layer soil with representation of freeze-thaw processes and litter inputs from a dynamically varying mixture of the main peatland plant functional types: mosses, shrubs and graminoids. The model was calibrated and tested for a sub-Arctic mire in Stordalen, Sweden, and validated at a temperate bog site in Mer Bleue, Canada. A regional evaluation of simulated carbon fluxes, hydrology and vegetation dynamics encompassed additional locations spread across Scandinavia. Simulated peat accumulation was found to be generally consistent with published data and the model was able to capture reported long-term vegetation dynamics, water table position and carbon fluxes. A series of sensitivity experiments were carried out to investigate the vulnerability of high-latitude peatlands to climate change. We found that the Stordalen mire may be expected to sequester more carbon in the first half of the 21st century due to milder and wetter climate conditions, a longer growing season, and the CO2 fertilization effect, turning into a carbon source after mid-century because of higher decomposition rates in response to warming soils.

Influence of different kind of peats on some physic-chemical properties, biochemical activity, the content of different forms of nitrogen and fractions of humic substances of The Great Vasyugan Mire

NASA Astrophysics Data System (ADS)

Inisheva, L. I.; Szajdak, L.

2009-04-01

Mires, or peatlands belong to the wetlands ecosystems where carbon is bounded in primary production and deposited as peat in water saturated, anoxic conditions. In those conditions, the rate of the supply of new organic matter has exceeded that the decomposition, resulting in carbon accumulation. Place of sampling belongs to an oligotrophic landscapes of the river Klyuch basin in spurs of Vasyugan mire. The catchment represents reference system for Bokchar swampy area (political district of Tomsk region). Landscape profile crosses main kinds of swampy biogeocoenosis (BGC) toward the mire center: paludal tall mixed forest, pine undershrub Sphagnum (high riam, trans-accumulative part of a profile, P2), pine-undershrub Sphagnum (low riam, transit part, P3), sedge-moss swamp (eluvial part, P5). The latter represents an eluvial part of a slope of watershed massif where it is accomplished discharge of excess, surface, soil-mire waters. The depth of peat deposit of sedge-moss swamp reaches 2,5m. To the depth of 0,6m there is a layer of Sphagnum raised bog peat, then it is a mesotrophic Scheuchzeria Sphagnum layer and at the bottom there is a thick layer of low-mire horsetail peat. The samples of peats were taken from two places (P2 and P3), both from the depth 0-75 cm of the great Vasyugan Mire. These materials represent (P2) Sphagnum fuscum peat (ash content ranged from 10.8 to 15.1%), but samples P3 belong to low-moor sedge peat (ash content ranged from 4.5-4.8%). The differences in water level, redox potential, pH, degree of degradation, bulk density, number of microorganisms, activity of enzymes, different kinds of nitrogen and humic substances were studied in two different peat soils characterized by different type of peat. In general in P2 the redox potential changed from 858 to /-140/ mV, higher activity of xanthine oxidase and peroxidase, different kinds of microorganisms (ammonifing bacteria and cellulose decomposing microorganisms) and different kinds of nitrogen (mineral, easily hydrolysable, hardly hydrolysable and non-hydrolyzable), bitumines, 3 fractions of humic acids and 3 fractions of fulvic acids were determined in the deep 0-25 cm than in 50-75 cm. The ratio HA/FA in the depth 0-25 cm was equal to from 1.87, but in the depth 50-75 cm was equal to 7.66. Contrary was observed for P3. For this peat with the increase of the deep of sampling the decrease of total nitrogen, activity of enzymes (xanthine oxidase and peroxidase) is connected with the changes of Fe+2/Fe+3 and lower difference of redox potential than in P2. The ratio HA/FA in the depth 0-25 cm was equal to 0.56, but in the depth 50-70 cm was equal to 0.84.

Hydrological Dynamics, Fire History and Carbon Accumulation in the Last Millennium in Western Siberia Reconstructed from a High Resolution Ombrotrophic Peat Archive

NASA Astrophysics Data System (ADS)

Lamentowicz, M.; Slowinski, M. M.; Marcisz, K.; Kolaczek, P.; Neumann, M.; Kaliszan, K.; Lapshina, E.; Gilbert, D.; Buttler, A.; Fialkiewicz-Koziel, B.; Jassey, V.; Laggoun-Defarge, F.

2014-12-01

Northern peatlands are important sinks of carbon. However, ongoing climate change and human impact trigger emission of the stored carbon into the atmosphere. Because of the progressive disturbances there is an urgent need to recognize these processes in space and time. We investigated a profile from a Mukhrino bog located close to the Mukhrino Field Station, about 20 km from Khanty-Mansiysk (60°54' N, 68°42' E). One meter peat core was subsampled in one-centimeter intervals. Pollen, testate amoebae, plant macrofossils, bulk density and carbon content were analyzed in high-resolution to reconstruct hydrology, droughts and carbon accumulation rates during the last 1200 years. We hypothesize that continental bogs of Siberia have been existing in under summer drought stress during the last millennium and hydrological change (dry shift) is also reflected in local fires. Palaeoecological work was accompanied by surface sampling to collect testate amoebae training set for transfer function development. These microorganisms have been scarcely studied in this part of the world. Redundancy analysis (RDA) showed that 23.7% of variance is explained by the model. Furthermore, water table appeared to be the most significant variable for sampled communities. Testate amoebae calibration data set performed the reliably using weighted averaging model (RMSEPboot=7.9, R2boot=0.74). According to our quantitative reconstruction, higher charcoal influx was inferred between AD 1975 and 1990 what suggests higher fire frequency. However, water table was the lowest between AD 1150 and AD 1965. The data show lack of correlation between peatland wetness and regional fires. Consequently, it suggests that peatland hydrological dynamics might be independent from fires frequency, as fires were caused by recent human activities in concomitance with the positive Arctic Oscillation Index during the last decade.

Technogenic magnetic particles in soils as evidence of historical mining and smelting activity: A case of the Brynica River Valley, Poland.

PubMed

Magiera, Tadeusz; Mendakiewicz, Maria; Szuszkiewicz, Marcin; Jabłońska, Mariola; Chróst, Leszek

2016-10-01

In the area of Brynica River basin (Upper Silesia, southern Poland) the exploitation and smelting of iron, silver and lead ores was historically documented since early Middle Ages. First investigations showed that metallurgy industry had a large impact from 9th century (AD) until the Second World War. The aim of the study was to use magnetic prospection to detect traces of past mining and ore smelting in Brynica River Valley located in Upper Silesia (southern Poland). The field screening was performed by measurement magnetic susceptibility (κ) on surface and in vertical profiles and was supported locally by gradiometric measurements. Vertical distribution of magnetic susceptibility values was closely associated with the type of soil use. Historical technogenic magnetic particles resulting from exploitation, processing, and smelting of iron, silver, and lead ores were accumulated in the soil layer at the depth 10 to 25cm. They were represented by sharp-edged particles of slag, coke, as well as various mineralogical forms of iron minerals and aggregates composed of carbon particles, aluminosilicate glass, and single particles of metallic iron. The additional geochemical study in adjacent peat bog supported by radiocarbon dating was also performed. The application of integrated geochemical-magnetic methods to reconstruct the historical accumulation of pollutants in the studied peat bog was effective. The magnetic peak, which was pointed out by magnetic analyses, is consistent with the presence of charcoal and pollution from heavy metals, such as Ag, Cd, Cu, Fe, Pb, or Sn. The results of this work will be helpful for the further study of human's impact on the environment related to the historical and even pre-historical ore exploitation and smelting and also used for better targeting the archeological excavations on such areas. Copyright © 2016 Elsevier B.V. All rights reserved.

Reorganization of vegetation, hydrology and soil carbon after permafrost degradation across heterogeneous boreal landscapes

USGS Publications Warehouse

Jorgenson, M. Torre; Harden, Jennifer; Kanevskiy, Mikhail; O'Donnell, Jonathan; Wickland, Kim; Ewing, Stephanie; Manies, Kristen; Zhuang, Qianlai; Shur, Yuri; Striegl, Robert G.; Koch, Joshua C.

2013-01-01

The diversity of ecosystems across boreal landscapes, successional changes after disturbance and complicated permafrost histories, present enormous challenges for assessing how vegetation, water and soil carbon may respond to climate change in boreal regions. To address this complexity, we used a chronosequence approach to assess changes in vegetation composition, water storage and soil organic carbon (SOC) stocks along successional gradients within four landscapes: (1) rocky uplands on ice-poor hillside colluvium, (2) silty uplands on extremely ice-rich loess, (3) gravelly–sandy lowlands on ice-poor eolian sand and (4) peaty–silty lowlands on thick ice-rich peat deposits over reworked lowland loess. In rocky uplands, after fire permafrost thawed rapidly due to low ice contents, soils became well drained and SOC stocks decreased slightly. In silty uplands, after fire permafrost persisted, soils remained saturated and SOC decreased slightly. In gravelly–sandy lowlands where permafrost persisted in drier forest soils, loss of deeper permafrost around lakes has allowed recent widespread drainage of lakes that has exposed limnic material with high SOC to aerobic decomposition. In peaty–silty lowlands, 2–4 m of thaw settlement led to fragmented drainage patterns in isolated thermokarst bogs and flooding of soils, and surface soils accumulated new bog peat. We were not able to detect SOC changes in deeper soils, however, due to high variability. Complicated soil stratigraphy revealed that permafrost has repeatedly aggraded and degraded in all landscapes during the Holocene, although in silty uplands only the upper permafrost was affected. Overall, permafrost thaw has led to the reorganization of vegetation, water storage and flow paths, and patterns of SOC accumulation. However, changes have occurred over different timescales among landscapes: over decades in rocky uplands and gravelly–sandy lowlands in response to fire and lake drainage, over decades to centuries in peaty–silty lowlands with a legacy of complicated Holocene changes, and over centuries in silty uplands where ice-rich soil and ecological recovery protect permafrost.

Carbon cycling responses to a water table drawdown and decadal vegetation changes in a bog

NASA Astrophysics Data System (ADS)

Talbot, J.; Roulet, N. T.

2009-12-01

The quantity of carbon stored in peat depends on the imbalance between production and decomposition of organic matter. This imbalance is mainly controlled by the wetness of the peatland, usually described by the water table depth. However, long-term processes resulting from hydrological changes, such as vegetation succession, also play a major role in the biogeochemistry of peatlands. Previous studies have looked at the impact of a water table lowering on carbon fluxes in different types of peatlands. However, most of these studies were conducted within a time frame that did not allow the examination of vegetation changes due to the water table lowering. We conducted a study along a drainage gradient resulting from the digging of a drainage ditch 85 years ago in a portion of the Mer Bleue bog, located near Ottawa, Canada. According to water table reconstructions based on testate amoeba, the drainage dropped the water table by approximately 18 cm. On the upslope side of the ditch, the water table partly recovered and the vegetation changed only marginally. However, on the downslope side of the ditch, the water table stayed persistently lower and trees established (Larix and Betula). The importance of Sphagnum decreased with a lower water table, and evergreen shrubs were replaced by deciduous shrubs. The water table drop and subsequent vegetation changes had combined and individual effects on the carbon functioning of the peatland. Methane fluxes decreased because of the water table lowering, but were not affected by vegetation changes, whereas respiration and net ecosystem productivity were affected by both. The carbon storage of the system increased because of an increase in plant biomass, but the long-term carbon storage as peat decreased. The inclusion of the feedback effect that vegetation has on the carbon functioning of a peatland when a disturbance occurs is crucial to simulate the long-term carbon balance of this ecosystem.

Airborne Petcoke Dust is a Major Source of Polycyclic Aromatic Hydrocarbons in the Athabasca Oil Sands Region.

PubMed

Zhang, Yifeng; Shotyk, William; Zaccone, Claudio; Noernberg, Tommy; Pelletier, Rick; Bicalho, Beatriz; Froese, Duane G; Davies, Lauren; Martin, Jonathan W

2016-02-16

Oil sands mining has been linked to increasing atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in the Athabasca oil sands region (AOSR), but known sources cannot explain the quantity of PAHs in environmental samples. PAHs were measured in living Sphagnum moss (24 sites, n = 68), in sectioned peat cores (4 sites, n = 161), and snow (7 sites, n = 19) from ombrotrophic bogs in the AOSR. Prospective source samples were also analyzed, including petroleum coke (petcoke, from both delayed and fluid coking), fine tailings, oil sands ore, and naturally exposed bitumen. Average PAH concentrations in near-field moss (199 ng/g, n = 11) were significantly higher (p = 0.035) than in far-field moss (118 ng/g, n = 13), and increasing temporal trends were detected in three peat cores collected closest to industrial activity. A chemical mass-balance model estimated that delayed petcoke was the major source of PAHs to living moss, and among three peat core the contribution to PAHs from delayed petcoke increased over time, accounting for 45-95% of PAHs in contemporary layers. Petcoke was also estimated to be a major source of vanadium, nickel, and molybdenum. Scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed large petcoke particles (>10 μm) in snow at near-field sites. Petcoke dust has not previously been considered in environmental impact assessments of oil sands upgrading, and improved dust control from growing stockpiles may mitigate future risks.

Greenhouse gas balance of a semi-natural peatbog in northern Scotland

NASA Astrophysics Data System (ADS)

Levy, P. E.; Gray, A.

2015-09-01

Northern peatlands have been accumulating organic matter since the start of the Holocene, and are now a substantial store of terrestrial carbon. However, their current status as carbon sinks is less clear, because of the possible effects of climate change, air pollution, grazing and drainage etc., and the difficulties of accurate measurement with suitable time resolution. Such measurements are particularly lacking in the UK. Here, we present multi-year eddy covariance measurements of the carbon fluxes at a relatively undisturbed ombrotrophic blanket bog in the Flow Country of northern Scotland. The site consistently acted as a moderate sink for CO2 over all the measurement years (mean net ecosystem exchange (NEE) of -114 g C m-2 y-1), similar in magnitude to other measurements in the boreal and tundra zones, and rather higher than the existing measurements at other sites in the UK and Ireland. Generally, the NEE of CO2 was relatively insensitive to moderate inter-annual variations in weather. Non-CO2 losses comprised 11% of gross primary production, mainly from methane emissions. Accounting for these terms, the net ecosystem carbon balance was -50 g C-CO2 eq m-2 y-1. The contemporary carbon sink was larger than estimates from local peat cores, based on peat accumulation over the last several thousand years, but in the middle of the range of estimates which used spheroidal carbonaceous particles to estimate peat accumulation rates over the last century.

High specificity but contrasting biodiversity of Sphagnum-associated bacterial and plant communities in bog ecosystems independent of the geographical region.

PubMed

Opelt, Katja; Berg, Christian; Schönmann, Susan; Eberl, Leo; Berg, Gabriele

2007-10-01

Mosses represent ecological niches that harbor a hitherto largely uncharacterized microbial diversity. To investigate which factors affect the biodiversity of bryophyte-associated bacteria, we analyzed the bacterial communities associated with two moss species, which exhibit different ecological behaviors and importance in bog ecosystems, Sphagnum magellanicum and Sphagnum fallax, from six temperate and boreal bogs in Germany and Norway. Furthermore, their surrounding plant communities were studied. Molecular analysis of bacterial communities was determined by single-strand conformation polymorphism (SSCP) analysis using eubacterial and genus-specific primers for the dominant genera Burkholderia and Serratia as well as by sequence analysis of a Burkholderia 16S rRNA gene clone library. Plant communities were analyzed by monitoring the abundance and composition of bryophyte and vascular plant species, and by determining ecological indicator values. Interestingly, we found a high degree of host specificity for associated bacterial and plant communities of both Sphagnum species independent of the geographical region. Calculation of diversity indices on the basis of SSCP gels showed that the S. fallax-associated communities displayed a statistically significant higher degree of diversity than those associated with S. magellanicum. In contrast, analyses of plant communities of Sphagnum-specific habitats resulted in a higher diversity of S. magellanicum-specific habitats for all six sites. The higher content of nutrients in the S. fallax-associated ecosystems can explain higher diversity of microorganisms.

Experimental Nitrogen Deposition Alters Post-fire Carbon Balance Recovery in Alberta Bogs

NASA Astrophysics Data System (ADS)

Wieder, R. K.; Vile, M. A.; Scott, K. D.; Albright, C. M.; McMillen, K.

2016-12-01

Bogs and fens occupy about 30% of the landscape across northern Alberta, Canada and function regionally as a net sink for atmospheric CO2-C, the strength of which is strongly influenced by the frequency and extent of wildfires. Alberta peatlands have persisted at the low end of the global range of annual atmospheric nitrogen (N) deposition (< 2 kg ha-1 yr-1), but oil sands development in the Athabasca Oil Sands Region has led to regionally elevated atmospheric N deposition. To examine the effects of elevated N deposition on bog net CO2 exchange, we experimentally applied N (as NH4NO3 solutions) to replicated plots at levels equivalent to controls (C: no water additions), 0 (water only), 10, and 20 kg/ha/yr at five bog sites, aged at 2, 12, 32, 73, and 113 years since fire in 2013 (hummocks and hollows in 6 plots per N treatment per site). Understory net ecosystem exchange of CO2 (NEE) was measured repeatedly throughout the 2013-2016 growing seasons using the closed chamber approach. Averaged across all years, sites, plots, and hummocks versus hollows, N addition stimulated NEE rates (C and 0 treatments: 0.46 µmol m-2 s-1; 10 and 20 treatments: 1.16 µmol m-2 s-1) and to a much lesser extent understory dark respiration (ER) rates (C and 0 treatments: -3.26 µmol m-2 s-1; 10 and 20 treatments: -3.43 µmol m-2 s-1). On an annual basis, averaged across all years, sites, and plots, N addition also stimulated NEE for hummocks (C and 0 treatments: -1.0 mol C m-2 yr-1; 10 and 20 treatments: 15.7 mol C m-2 yr-1), but not hollows. Experimental N addition had minimal effects on annual ER. The nature of the N response, however, differed between sites and years. Further, experimental N addition had no effect on the net primary production of Sphagnum fuscum, the dominant peat-forming moss. Thus, the enhancement of the net CO2-C sink through N addition occurs through stimulation of short-statured vascular shrub growth and biomass, with implications for the structure and function of bog understories as they recover after fire under different N deposition regimes.

Seasonally frozen layer in natural and drained peatlands at the South of West Siberia, Russia

NASA Astrophysics Data System (ADS)

Dyukarev, Egor; Kiselev, Maxim; Voropay, Nadezhda; Preis, Yulia

2017-04-01

The temperature regime of soils in natural and drained peatlands at Bakchar bog located in the South Taiga zone of West Siberia is studied. Soil temperature for depths up to 320 cm was registered using autonomous temperature profile recorder during the period from August 2010 to September 2016. Maximal and minimal temperatures were registered at surface in July and February, consequently. Extreme soil temperatures at 320 cm depth shifts to December (maximum) and July (minimum) reducing absolute values. Annual peat soil temperature amplitude decrease with depth from 21,8 °C on surface to 1,1 °C at 320 cm. The analysis of daily, month and annual mean data of temperature in peat soil has shown that seasonally frozen layer was registered up to 20-60 cm depth. The duration of seasonally freeze layer existence varies from 130 to 180 days. Drained peatlands with the lowest water table have highest freeze depth. Soil at water-logged sedge-sphagnum fen in winter is warmer than soil in ryam ecosystem and mineral soil at upland. Maximal freezing depth in peatlands is up to 3 times lower than at drain areas.

Miocene and Pliocene lacustrine and fluvial sequences, Upper Ramparts and Canyon village, Porcupine river, east-central Alaska

USGS Publications Warehouse

Fouch, T.D.; Carter, L.D.; Kunk, Michael J.; Smith, C.A.S.; White, J.M.

1994-01-01

Cenozoic strata exposed along the Porcupine River between the Upper Ramparts and Canyon Village, Alaska, can be divided into five unconformity-bounded units (sequences) which are: lower and middle Miocene unit A, the white sandy fluvial sequence with peat beds; middle Miocene unit B, the basalt sequence-part B1 is basalt, and part B2 is organic-rich sedimentary beds; upper Miocene unit C, mudrock-dominated lake sequence; late Miocene or Pliocene to Pleistocene unit D, terrace gravels, detrital organic matter and associated sediments, and Holocene unit E, mixed sand and gravel-rich sediment and other sedimentary material including peat and eolian silt. The sequence (unit A) of lower and middle Miocene fluvial deposits formed in streams and on flood plains, just before the inception of local volanism. Fossil pollen from unit A suggests conifer-dominated regional forests and cool temperate climates. Peat beds and lake deposits from unit B contain pollen that indicates a warmer temperate climate coinciding with the middle Miocene thermal maximum. The lake deposits (unit C) downstream from the basalts accumulated in a small basin which resulted from a hydrologic system that was dammed in the late Miocene but breached soon thereafter. The lower part of the terrace gravels (unit D) expresses breaching of the dammed hydrologic system (of unit C). The Porcupine River became a major tributary of the Yukon River in late Pleistocene time when Laurentide ice blocked drainage from the Yukon interior basins causing meltwater to spill over the low divide separating it from the Porcupine River drainage initiating erosion and capture of the Yukon interior basins. ?? 1994.

Dissolved organic carbon fluxes from soils in the Alaskan coastal temperate rainforest

NASA Astrophysics Data System (ADS)

D'Amore, D. V.; Edwards, R.; Hood, E. W.; Herendeen, P. A.; Valentine, D.

2011-12-01

Soil saturation and temperature are the primary factors that influence soil carbon cycling. Interactions between these factors vary by soil type, climate, and landscape position, causing uncertainty in predicting soil carbon flux from. The soils of the North American perhumid coastal temperate rainforest (NCTR) store massive amounts of carbon, yet there is no estimate of dissolved organic carbon (DOC) export from different soil types in the region. There are also no working models that describe the influence of soil saturation and temperature on the export of DOC from soils. To address this key information gap, we measured soil water table elevation, soil temperature, and soil and stream DOC concentrations to calculate DOC flux across a soil hydrologic gradient that included upland soils, forested wetland soils, and sloping bog soils in the NCTR of southeast Alaska. We found that increased soil temperature and frequent fluctuations of soil water tables promoted the export of large quantities of DOC from wetland soils and relatively high amounts of DOC from mineral soils. Average area-weighted DOC flux ranged from 7.7 to 33.0 g C m-2 y-1 across a gradient of hydropedologic soil types. The total area specific export of carbon as DOC for upland, forested wetland and sloping bog catchments was 77, 306, and 329 Kg C ha-1 y-1 respectively. The annual rate of carbon export from wetland soils in this region is among the highest reported in the literature. These findings highlight the importance of terrestrial-aquatic fluxes of DOC as a pathway for carbon loss in the NCTR.

Excess growing-season water limits lowland black spruce productivity

NASA Astrophysics Data System (ADS)

Dymond, S.; Kolka, R. K.; Bolstad, P. V.; Gill, K.; Curzon, M.; D'Amato, A. W.

2015-12-01

The annual growth of many tree species is limited by water availability, with growth increasing as water becomes less scarce. In lowland bogs of northern Minnesota, however, black spruce (Picea mariana) is often exposed to excess water via high water table elevations. These trees grow in thick deposits of organic mucky peat and often have shallow rooting systems to avoid the complete submersion of roots in water. While it is generally believed that black spruce decrease growth rates with rising water table elevations, this hypothesis has not been tested in situ. We used a unique, 50-year record of daily bog water table elevations at the Marcell Experimental Forest (MEF) in northern Minnesota to investigate the relationship between climate and black spruce productivity. Nine 1/20th ha circular plots were established in five different bogs and tree height, diameter-at-breast-height (DBH), and crown class were recorded. Additionally, two perpendicular cores were collected on all trees greater than 10 cm diameter-at-breast-height. Tree cores were sanded, mounted, cross-dated, and de-trended according to standard dendrochronological procedures. Ring width measurements were correlated with precipitation, temperature, and water table elevation using package BootRes in R to determine the climatic variables most associated with stand level productivity. Across the different plots, we found that early growing season water table elevation (May and June) was negatively correlated with both individual and stand-level black spruce growth (p < 0.01), while growth was positively correlated with March temperatures (p < 0.01). No significant relationships existed between black spruce growth and monthly precipitation. If summer water table elevations in these peatland ecosystems rise as is anticipated with more extreme precipitation events due to climate change, we could see an overall decrease in the stand level productivity of black spruce.

Swift recovery of Sphagnum nutrient concentrations after excess supply.

PubMed

Limpens, Juul; Heijmans, Monique M P D

2008-08-01

Although numerous studies have addressed the effects of increased N deposition on nutrient-poor environments such as raised bogs, few studies have dealt with to what extent, and on what time-scale, reductions in atmospheric N supply would lead to recovery of the ecosystems in question. Since a considerable part of the negative effects of elevated N deposition on raised bogs can be related to an imbalance in tissue nutrient concentrations of the dominant peat-former Sphagnum, changes in Sphagnum nutrient concentration after excess N supply may be used as an early indicator of ecosystem response. This study focuses on the N and P concentrations of Sphagnum magellanicum and Sphagnum fallax before, during and after a factorial fertilization experiment with N and P in two small peatlands subject to a background bulk deposition of 2 g N m(-2) year(-1). Three years of adding N (4.0 g N m(-2) year(-1)) increased the N concentration, and adding P (0.3 g P m(-2) year(-1)) increased the P concentration in Sphagnum relative to the control treatment at both sites. Fifteen months after the nutrient additions had ceased, N concentrations were similar to the control whereas P concentrations, although strongly reduced, were still slightly elevated. The changes in the N and P concentrations were accompanied by changes in the distribution of nutrients over the capitulum and the stem and were congruent with changes in translocation. Adding N reduced the stem P concentration, whereas adding P reduced the stem N concentration in favor of the capitulum. Sphagnum nutrient concentrations quickly respond to reductions in excess nutrient supply, indicating that a management policy aimed at reducing atmospheric nutrient input to bogs can yield results within a few years.

Dissolved Organic Carbon Cycling and Transformation Dynamics in A Northern Forested Peatland

NASA Astrophysics Data System (ADS)

Tfaily, M. M.; Lin, X.; Chanton, P. R.; Steinweg, J.; Esson, K.; Kostka, J. E.; Cooper, W. T.; Schadt, C. W.; Hanson, P. J.; Chanton, J.

2013-12-01

Peatlands sequester one-third of all soil carbon and currently act as major sinks of atmospheric carbon dioxide. The ability to predict or simulate the fate of stored carbon in response to climatic disruption remains hampered by our limited understanding of the controls of carbon turnover and the composition and functioning of peatland microbial communities. A combination of advanced analytical chemistry and microbiology approaches revealed that organic matter reactivity and microbial community dynamics were closely coupled in an extensive field dataset compiled at the S1 bog site established for the SPRUCE program, Marcell Experimental Forest (MEF). The molecular composition and decomposition pathways of dissolved organic carbon (DOC) were contrasted using parallel factor (PARAFAC)-modeled excitation emission fluorescence spectroscopy (EEMS) and FT-ICR MS. The specific UV absorbance (SUVA) at 254 nm was calculated as an indicator of aromaticity. Fluorescence intensity ratios (BIX and FI) were used to infer the relative contributions from solid phase decomposition and microbial production. Distributions of bulk DOC, its stable (δ13C) and radioactive (Δ14C) isotopic composition were also utilized to infer information on its dynamics and transformation processes. Strong vertical stratification was observed in organic matter composition, the distribution of mineralization products (CO2, CH4), respiration rates, and decomposition pathways, whereas smaller variations were observed between sites. A decline in the aromaticity of pore water DOC was accompanied by an increase in microbially-produced DOC. Solid phase peat, on the other hand, became more humified and highly aromatic with depth. These observations were consistent with radiocarbon data that showed that the radiocarbon signatures of microbial respiration products in peat porewaters more closely resemble those of DOC rather than solid peat, indicating that carbon from recent photosynthesis is fueling the majority of the decomposition, even in the subsurface. Stable isotope geochemistry paralleled with vertical changes in methanogen community composition to reveal a mid-depth maximum in acetoclastic methanogenesis, while hydrogenotrophic methanogenesis appears to dominate deeper peat layers. Archaea increased in relative abundance with depth, comprising up to 60 % of the microbial community in the deep peat below 75 cm depth. The Crenarchaeota, Archaea that are not known to produce methane, are suggested to play a critical role in the carbon cycle of deeper peat layers. This is corroborated by evidence from a C isotope mass balance, which indicates that processes other than methanogenesis (fermentation, anaerobic respiration) predominate in the deep peat leading to dominance of CO2 production at depth.

Shallow peatland ecohydrology - the control of peat depth on moss productivity

NASA Astrophysics Data System (ADS)

Dixon, Simon; Kettridge, Nicholas; Moore, Paul; Devito, Kevin; Tilak, Amey; Petrone, Rich; Mendoza, Carl; Waddington, Mike

2017-04-01

Northern peatlands represent an important sink in the global carbon cycle. Shallow peatlands and marginal connective wetlands can be essential components of many northern peatland landscape mosaics, playing a vital role in landscape connectivity and wider landscape hydrology. However the ecohydrological function of these shallow, marginal systems has been largely overlooked, with peatland hydrology research focused on relatively deep bog systems. In order to predict landscape scale wetland function and its vulnerability to climate change we need to understand how these shallow connective systems function. The balance between moss productivity and water loss provide a key component of these systems, as water use efficiency controls the rate of moss growth and thus controls the amount of atmospheric carbon sequestered in peat. Understanding how productivity of shallow peatland systems responds to changes in evaporative stress will aid predictions of peatland landscape hydrological function in a changing climate. To determine the factors influencing peat productivity, water balance simulations using Hydrus 1-D were conducted over annual growing seasons for different soil profile depths, compositions and antecedent moisture conditions. Our results demonstrate a bimodal distribution of peatland responses; either primarily conserving water by limiting evapotranspiration or, maximizing productivity. For sustained periods of evaporative stress, shallow marginal systems are least able to buffer periods of evaporative stress due to limited labile water storage, and will limit evaporation, conserve water and be less productive. Conversely, where present, both deep water storage and a shallow initial water table prolong the onset of high vegetative stress, thus maximizing moss productivity. However, a total depth of 0.8 m is identified as the threshold above which increasing peat depth has no further effect on changing vegetative stress response and thus landscape function. These results are important as moss productivity, along with rate of organic matter decay are the two principle factors controlling the build-up of peat, and therefore sequestration of carbon. With a predicted increase in the frequency and size of rain events in northern latitudes our results indicate the productivity of shallow wetland systems may increase, but greater moisture availability will increase the likelihood they remain as wetlands in a changing climate.

A pore-size classification for peat bogs derived from unsaturated hydraulic properties

NASA Astrophysics Data System (ADS)

Weber, Tobias Karl David; Iden, Sascha Christian; Durner, Wolfgang

2017-12-01

In ombrotrophic peatlands, the moisture content of the acrotelm (vadoze zone) controls oxygen diffusion rates, redox state, and the turnover of organic matter. Thus, variably saturated flow processes determine whether peatlands act as sinks or sources of atmospheric carbon, and modelling these processes is crucial to assess effects of changed environmental conditions on the future development of these ecosystems. We show that the Richards equation can be used to accurately describe the moisture dynamics under evaporative conditions in variably saturated peat soil, encompassing the transition from the topmost living moss layer to the decomposed peat as part of the vadose zone. Soil hydraulic properties (SHP) were identified by inverse simulation of evaporation experiments on samples from the entire acrotelm. To obtain consistent descriptions of the observations, the traditional van Genuchten-Mualem model was extended to account for non-capillary water storage and flow. We found that the SHP of the uppermost moss layer reflect a pore-size distribution (PSD) that combines three distinct pore systems of the Sphagnum moss. For deeper samples, acrotelm pedogenesis changes the shape of the SHP due to the collapse of inter-plant pores and an infill with smaller particles. This leads to gradually more homogeneous and bi-modal PSDs with increasing depth, which in turn can serve as a proxy for increasing state of pedogenesis in peatlands. From this, we derive a nomenclature and size classification for the pore spaces of Sphagnum mosses and define inter-, intra-, and inner-plant pore spaces, with effective pore diameters of > 300, 300-30, and 30-10 µm, respectively.

Greenhouse gas efflux from an impacted Malaysian tropical peat swamp (Invited)

NASA Astrophysics Data System (ADS)

Waldron, S.; Vihermaa, L. E.; Evers, S.; Garnett, M.; Newton, J.; Padfield, R.

2013-12-01

Tropical peatlands constitute ~11% of global peatland area and ~12% of the global peat C pool. Malaysia alone contains 10% of tropical peats. Due to rising global demands for food and biofuels, SE-Asia peat swamp forest ecosystems are threatened by increasing amounts of drainage, fire and conversion to plantation. These processes can change the GHG emissions and thus net ecosystem C balance. However, in comparison to temperate and boreal peatlands, there is a lack of data on terrestrial-aquatic-atmospheric carbon transfer from tropical peatlands, both those that are little disturbed and those facing anthropogenic pressures. Lateral transport of soil-respired carbon, and fluvial respiration or UV-oxidation of terrestrial DOC primes atmospheric carbon dioxide efflux. We now know that DOC lost from disturbed tropical peat swamp forests can be centuries to millennia old and originates deep within the peat column - this carbon may fuel efflux of old carbon dioxide and so anthropogenic land-use change renders the older, slower carbon cycles shorter and faster. Currently we have no knowledge of how significant ';older-slower' terrestrial-aquatic-atmospheric cycles are in disturbed tropical peatlands. Further, in some areas for commercial reasons, or by conservation bodies trying to minimise peat habitat loss, logged peats have been left to regenerate. Consequently, unpicking the legacy of multiple land uses on magnitude, age and source of GHG emissions is challenging but required to support land management decisions and projections of response to a changing climate. Here, we present the results of our first field campaign in July 2013 to the Raja Musa and Sungai Karang Peat Swamp Forest Reserves in North Selangor, Malaysia. This is one of Malaysia's largest oceanic peat swamps, and has been selectively logged and drained for 80 years, but is now subject to a 30 year logging ban to aid forest regeneration and build up wood stocks. From sites subject to different land use, we will present measurements of i) spatial variation in fluvial carbon dioxide and methane concentrations and associated efflux rates, and ii) the stable carbon isotopic composition of DIC and novel determination of the age of the effluxed carbon dioxide. From this we can consider if younger-faster or older-slower carbon cycling dominates the terrestrial-aquatic-atmospheric C transfer during this dry period sampling.

Bacterial populations and environmental factors controlling cellulose degradation in an acidic Sphagnum peat.

PubMed

Pankratov, Timofey A; Ivanova, Anastasia O; Dedysh, Svetlana N; Liesack, Werner

2011-07-01

Northern peatlands represent a major global carbon store harbouring approximately one-third of the global reserves of soil organic carbon. A large proportion of these peatlands consists of acidic Sphagnum-dominated ombrotrophic bogs, which are characterized by extremely low rates of plant debris decomposition. The degradation of cellulose, the major component of Sphagnum-derived litter, was monitored in long-term incubation experiments with acidic (pH 4.0) peat extracts. This process was almost undetectable at 10°C and occurred at low rates at 20°C, while it was significantly accelerated at both temperature regimes by the addition of available nitrogen. Cellulose breakdown was only partially inhibited in the presence of cycloheximide, suggesting that bacteria participated in this process. We aimed to identify these bacteria by a combination of molecular and cultivation approaches and to determine the factors that limit their activity in situ. The indigenous bacterial community in peat was dominated by Alphaproteobacteria and Acidobacteria. The addition of cellulose induced a clear shift in the community structure towards an increase in the relative abundance of the Bacteroidetes. Increasing temperature and nitrogen availability resulted in a selective development of bacteria phylogenetically related to Cytophaga hutchinsonii (94-95% 16S rRNA gene sequence similarity), which densely colonized microfibrils of cellulose. Among isolates obtained from this community only some subdivision 1 Acidobacteria were capable of degrading cellulose, albeit at a very slow rate. These Acidobacteria represent indigenous cellulolytic members of the microbial community in acidic peat and are easily out-competed by Cytophaga-like bacteria under conditions of increased nitrogen availability. Members of the phylum Firmicutes, known to be key players in cellulose degradation in neutral habitats, were not detected in the cellulolytic community enriched at low pH. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Investigating the potential of floating mires as record of palaeoenvironmental changes

NASA Astrophysics Data System (ADS)

Zaccone, C.; Adamo, P.; Giordano, S.; Miano, T. M.

2012-04-01

Peat-forming floating mires could provide an exceptional resource for palaeoenvironmental and environmental monitoring studies, as much of their own history, as well as the history of their surrounds, is recorded in their peat deposits. In his Naturalis historia (AD 77-79), Pliny the Elder described floating islands on Lake Vadimonis (now Posta Fibreno Lake, Italy). Actually, a small floating island (ca. 35 m of diameter and 3 m of submerged thickness) still occurs on this calcareous lake fed by karstic springs at the base of the Apennine Mountains. Here the southernmost Italian populations of Sphagnum palustre occur on the small surface of this floating mire known as "La Rota", i.e., a cup-formed core of Sphagnum peat and rhizomes of Helophytes, erratically floating on the water-body of a submerged doline, annexed to the easternmost edge of the lake, characterised by the extension of a large reed bed. Geological evidence point out the existence in the area of a large lacustrine basin since Late Pleistocene. The progressive filling of the lake caused by changing in climatic conditions and neotectonic events, brought about the formation of peat deposits in the area, following different depositional cycles in a swampy environment. Then, a round-shaped portion of fen, originated around lake margins in waterlogged areas, was somehow isolated from the bank and started to float. Coupling data about concentrations and fluxes of several major and trace elements of different origin (i.e., dust particles, volcanic emissions, cosmogenic dusts and marine aerosols), with climate records (plant micro- and macrofossils, pollens, isotopic ratios), biomolecular records (e.g., lipids), detailed age-depth modelling (i.e., 210Pb, 137Cs, 14C), and humification indexes, the present work is hoped to identify and better understand the reliability of this particular "archive", and thus possible relationships between biogeochemical processes occurring in this floating bog and environmental changes.

A study of Minnesota land and water resources using remote sensing

NASA Technical Reports Server (NTRS)

Shepherd, W. G. (Principal Investigator)

1977-01-01

The author has identified the following significant results. Both LANDSAT imagery and digital data were studied for usefulness in surveying water conditions of Minnesota lakes. Initial consideration was given to analysis of LANDSAT image densities because of the low technologic and cost requirements. The techniques employed, however, yield inconsistent and unreliable results. A set of criteria are given for using LANDSAT data in identification of three categories of particulate contaminants in Lake Superior. A linear transformation giving the relationship between the residual LANDSAT intensities and concentrations of three contaminants was obtained from correlation of remote sensing data with insitu measurements. LANDSAT imagery was found useful in placing peat bogs and fens in their respective geologic settings. Artificial disturbances and drainageways in peatlands could be recognized and classified.

Soil catenas on denudation plains in the forest-tundra and northern taiga zones of the Kola Peninsula

NASA Astrophysics Data System (ADS)

Urusevskaya, I. S.

2017-07-01

Morphogenetic features of soils of two catenas developed on sandy to loamy sandy moraine deposits in the forest-tundra and northern taiga zones on denudation plains of the Kola Peninsula are discussed. It is shown that these catenas are similar with respect to the major directions of soil formation, regularities of soil distribution by the elements of mesotopography, and the factors of the soil cover differentiation. The differences between the catenas are of quantitative character and are related to the intensities of manifestation of the particular processes and features. Both catenas are characterized by the pronounced differentiation of soils with respect to their moistening with hydromorphic peat bog soils in the subordinate positions and Al-Fe-humus podzols in the automorphic positions.

Eddy covariance measurements of greenhouse gases from a restored and rewetted raised bog ecosystem.

NASA Astrophysics Data System (ADS)

Lee, S. C.; Christen, A.; Black, T. A.; Johnson, M. S.; Ketler, R.; Nesic, Z.; Merkens, M.

2015-12-01

Wetland ecosystems play a significant role in the global carbon (C) cycle. Wetlands act as a major long-term storage of carbon by sequestrating carbon-dioxide (CO2) from the atmosphere. Meanwhile, they can emit significant amounts of methane (CH4) due to anaerobic microbial decomposition. The Burns Bog Ecological Conservancy Area (BBECA) is recognized as one of Canada's largest undeveloped natural areas retained within an urban area. Historically, it has been substantially reduced in size and degraded by peat mining and agriculture. Since 2005, the bog has been declared a conservancy area, and the restoration efforts in BBECA focus on rewetting the disturbed ecosystems to promote a transition back to a raised bog. A pilot study measured CH4, CO2 and N2O exchanges in 2014 and concluded to monitor CO2, CH4 fluxes continuously. From the perspective of greenhouse gas (GHG) emissions, CO2 sequestered in bog needs to be protected and additional CO2 and CH4 emissions due to land-cover change need to be reduced by wise management. In this study, we measured the growing-season (June-September) fluxes of CO2 and CH4 exchange using eddy covariance (EC). A floating platform with an EC system for both CO2 (closed-path) and CH4 (open-path) began operation in June 2015. During the growing-season, gross ecosystem photosynthesis (GEP) and ecosystem respiration (Re) averaged 5.87 g C m-2 day-1 and 2.02 g C m-2 day-1, respectively. The magnitude of GEP and Re were lower than in previous studies of pristine northern peatlands. The daily average CH4 emission was 0.99 (±1.14) g C m-2 day-1 and it was higher than in most previous studies. We also characterized how environmental factors affected the seasonal dynamics of these exchanges in this disturbed peatland. Our measurements showed that soil temperature and soil water content were major drivers of seasonal changes of GHG fluxes. The daily average GHG warming potential (GWP) of the emissions in the growing seasons (from CO2 and CH4) totals to 37.09 g CO2e m-2 day-1. CH4 was the significant constributor (99 % of GHG emissions) indicating that GHG exchange due to photosynthesis and respiration was of secondary order. Although oxygen limitation due to the high water table caused by the restoration strategy suppressed the Re it also promoted substantial CH4 formation under anoxic conditions.

Microbial communities of the deep unfrozen: Do microbes in taliks increase permafrost carbon vulnerability? (Invited)

NASA Astrophysics Data System (ADS)

Waldrop, M. P.; Blazewicz, S.; Jones, M.; Mcfarland, J. W.; Harden, J. W.; Euskirchen, E. S.; Turetsky, M.; Hultman, J.; Jansson, J.

2013-12-01

The vast frozen terrain of northern latitude ecosystems is typically thought of as being nearly biologically inert for the winter period. Yet deep within the frozen ground of northern latitude soils reside microbial communities that can remain active during the winter months. As we have shown previously, microbial communities may remain active in permafrost soils just below the freezing point of water. Though perhaps more importantly, microbial communities persist in unfrozen areas of water, soil, and sediment beneath water bodies the entire year. Microbial activity in taliks may have significant impacts on biogeochemical cycling in northern latitude ecosystems because their activity is not limited by the winter months. Here we present compositional and functional data, including long term incubation data, for microbial communities within permafrost landscapes, in permafrost and taliks, and the implications of these activities on permafrost carbon decomposition and the flux of CO2 and CH4. Our experiment was conducted at the Alaska Peatland Experiment (APEX) within the Bonanza Creek LTER in interior Alaska. Our site consists of a black spruce forest on permafrost that has degraded into thermokarst bogs at various times over the last five hundred years. We assume the parent substrate of the deep (1-1.5m) thermokarst peat was similar to the nearby forest soil and permafrost C before thaw. At this site, flux tower and autochamber data show that the thermokarst bog is a sink of CO2 , but a significant source of CH4. Yet this does not tell the whole story as these data do not fully capture microbial activity within the deep unfrozen talik layer. There is published evidence that within thermokarst bogs, relatively rapid decomposition of old forest floor material may be occurring. There are several possible mechanisms for this pattern; one possible mechanism for accelerated decomposition is the overwintering activities of microbial communities in taliks of thermokarst soils. To test this idea, we conducted anaerobic incubations of deep (1m) bog soils at two different temperatures to determine microbial temperature response functions. We also measured soil profile CO2 and CH4 concentrations and functional gene assays of the deep bog microbial community. Incubation data in combination with overwinter temperature profiles show that the talik has high potential rates of CO2 and CH4 production compared to the mass of C from forest floor and permafrost C to 1m depth. Results highlight the potential importance of taliks affecting the vulnerability of permafrost carbon to decomposition and reduction to methane.

Postglacial vegetation history of Mitkof Island, Alexander Archipelago, southeastern Alaska

USGS Publications Warehouse

Ager, T.A.; Carrara, P.E.; Smith, Jane L.; Anne, V.; Johnson, J.

2010-01-01

An AMS radiocarbon-dated pollen record from a peat deposit on Mitkof Island, southeastern Alaska provides a vegetation history spanning ∼12,900 cal yr BP to the present. Late Wisconsin glaciers covered the entire island; deglaciation occurred > 15,400 cal yr BP. The earliest known vegetation to develop on the island (∼12,900 cal yr BP) was pine woodland (Pinus contorta) with alder (Alnus), sedges (Cyperaceae) and ferns (Polypodiaceae type). By ∼12,240 cal yr BP, Sitka spruce (Picea sitchensis) began to colonize the island while pine woodland declined. By ∼11,200 cal yr BP, mountain hemlock (Tsuga mertensiana) began to spread across the island. Sitka spruce-mountain hemlock forests dominated the lowland landscapes of the island until ∼10,180 cal yr BP, when western hemlock (Tsuga heterophylla) began to colonize, and soon became the dominant tree species. Rising percentages of pine, sedge, and sphagnum after ∼7100 cal yr BP may reflect an expansion of peat bog habitats as regional climate began to shift to cooler, wetter conditions. A decline in alders at that time suggests that coastal forests had spread into the island's uplands, replacing large areas of alder thickets. Cedars (Chamaecyparis nootkatensis, Thuja plicata) appeared on Mitkof Island during the late Holocene.

Subtle shifts in microbial communities occur alongside the release of carbon induced by drought and rewetting in contrasting peatland ecosystems.

PubMed

Potter, Caitlin; Freeman, Chris; Golyshin, Peter N; Ackermann, Gail; Fenner, Nathalie; McDonald, James E; Ehbair, Abdassalam; Jones, Timothy G; Murphy, Loretta M; Creer, Simon

2017-09-12

Peat represents a globally significant pool of sequestered carbon. However, peatland carbon stocks are highly threatened by anthropogenic climate change, including drought, which leads to a large release of carbon dioxide. Although the enzymatic mechanisms underlying drought-driven carbon release are well documented, the effect of drought on peatland microbial communities has been little studied. Here, we carried out a replicated and controlled drought manipulation using intact peat 'mesocosm cores' taken from bog and fen habitats, and used a combination of community fingerprinting and sequencing of marker genes to identify community changes associated with drought. Community composition varied with habitat and depth. Moreover, community differences between mesocosm cores were stronger than the effect of the drought treatment, emphasising the importance of replication in microbial marker gene studies. While the effect of drought on the overall composition of prokaryotic and eukaryotic communities was weak, a subset of the microbial community did change in relative abundance, especially in the fen habitat at 5 cm depth. 'Drought-responsive' OTUs were disproportionately drawn from the phyla Bacteroidetes and Proteobacteria. Collectively, the data provide insights into the microbial community changes occurring alongside drought-driven carbon release from peatlands, and suggest a number of novel avenues for future research.

Postglacial vegetation history of Mitkof Island, Alexander Archipelago, southeastern Alaska

NASA Astrophysics Data System (ADS)

Ager, Thomas A.; Carrara, Paul E.; Smith, Jane L.; Anne, Victoria; Johnson, Joni

2010-03-01

An AMS radiocarbon-dated pollen record from a peat deposit on Mitkof Island, southeastern Alaska provides a vegetation history spanning ˜12,900 cal yr BP to the present. Late Wisconsin glaciers covered the entire island; deglaciation occurred > 15,400 cal yr BP. The earliest known vegetation to develop on the island (˜12,900 cal yr BP) was pine woodland ( Pinus contorta) with alder ( Alnus), sedges (Cyperaceae) and ferns (Polypodiaceae type). By ˜12,240 cal yr BP, Sitka spruce ( Picea sitchensis) began to colonize the island while pine woodland declined. By ˜11,200 cal yr BP, mountain hemlock ( Tsuga mertensiana) began to spread across the island. Sitka spruce-mountain hemlock forests dominated the lowland landscapes of the island until ˜10,180 cal yr BP, when western hemlock ( Tsuga heterophylla) began to colonize, and soon became the dominant tree species. Rising percentages of pine, sedge, and sphagnum after ˜7100 cal yr BP may reflect an expansion of peat bog habitats as regional climate began to shift to cooler, wetter conditions. A decline in alders at that time suggests that coastal forests had spread into the island's uplands, replacing large areas of alder thickets. Cedars ( Chamaecyparis nootkatensis, Thuja plicata) appeared on Mitkof Island during the late Holocene.

CRE dating on the scarps of large landslides affecting the Belledonne massif ( French Alps)

NASA Astrophysics Data System (ADS)

Lebrouc, V.; Baillet, L.; Schwartz, S.; Jongmans, D.; Gamond, J. F.; Bourles, D.; Le Roux, O.; Carcaillet, J.; Braucher, R.

2012-04-01

The southwestern edge of the Belledonne Massif (French Alps) consists of micaschists unconformably covered with Mesozoic sediments and Quaternary deposits. The morphology corresponds to a glacial plateau (Mont Sec plateau) bordered by steep slopes (around 40°), where moraines and peat bog subsist. The massif is incised by the East-West trending Romanche valley that was shaped by several cycles of quaternary glaciations and deglaciations. Slopes are affected by several active or past large scale rock mass instabilities. Cosmic Ray Exposure (CRE) dating was applied on the head scarps of three large landslides, one of which being the active Séchilienne landslide whose headscarp was already dated by Leroux et al. [2009]. Dating results suggest a concomitant initiation of these instabilities at about 7 ± 2 10Be ka, thousands years after the total downwastage of the valley. A different kinematic behaviour was however observed on two contiguous landslides for which continuous exposure profiles were obtained. On the Séchilienne landslide, 23 samples were collected from internal and lateral scarps, as well as on polished bedrock surfaces, with the aim of dating the internal kinematics of the landslide. Preliminary dating results obtained on polished surfaces and near the top of the scarps show unexpected low 10Be concentrations, suggesting the existence of thin moraine or peat bog deposits masking the bedrock, which have been subsequently eroded. The minimum thickness of these deposits was estimated assuming a constant denudation rate over time. Exposure date profiles show that the studied lateral and internal scarps were initiated at the same period as the Sechilienne headscarp. An increase in the exposure rate was also observed between 2 and 1 ka, in agreement with that evidenced along the headscarp. Forty other samples have been collected in the landslide to corroborate these results. Reference Le Roux, O., S. Schwartz , J.-F. Gamond, D. Jongmans, D. Bourles, R. Braucher, W. Mahaney, J. Carcaillet, and L. Leanni (2009). CRE dating on the head scarp of a major landslide (Séchilienne, French Alps), age constraints on Holocene kinematics. Earth and Planetary Science Letters, Vol. 280, 236-245.

Fimbriiglobus ruber gen. nov., sp. nov., a Gemmata-like planctomycete from Sphagnum peat bog and the proposal of Gemmataceae fam. nov.

PubMed

Kulichevskaya, Irina S; Ivanova, Anastasia A; Baulina, Olga I; Rijpstra, W Irene C; Sinninghe Damsté, Jaap S; Dedysh, Svetlana N

2017-02-01

An aerobic, budding, dark pink to red-pigmented bacterium was isolated from an acidic boreal Sphagnum peat bog and designated strain SP5T. Cells of this strain were non-motile spheres that were uniformly covered with crateriform pits and fimbria, and tended to form aggregates during growth in liquid media. Strain SP5T was capable of growth between pH 4.0 and pH 6.8 (optimum at pH 5.5-6.0) and at temperatures between 10 and 30 °C (optimum at 20-25 °C). The preferred growth substrates were sugars and some heteropolysaccharides. The major fatty acids were C20 : 1ω9c, C16 : 1ω9c and C16 : 0, and the major polar lipid was trimethylornithine. Cells contained also significant amounts of bound (ω-1)OH-C30 : 1 fatty acid. The quinone was menaquinone-6, and the G+C content of the DNA was 60.7 mol%. Strain SP5T was a member of the order Planctomycetales and belonged to the phylogenetic lineage defined by the genus Gemmata. It displayed 88 and 89 % 16S rRNA gene sequence similarity to Gemmata obscuriglobusUQM 2246T and 'Gemmata massiliana' IIL30, 89 % to Zavarzinella formosa A10T and 86 % to Telmatocola sphagniphila SP2T. However, strain SP5T differed from members of these genera by cell morphology, substrate utilization pattern and fatty acid composition. Based on these data, the novel isolate should be considered as representing a novel species of a new genus of planctomycetes, for which the name Fimbriiglobus ruber gen. nov., sp. nov, is proposed. The type strain is SP5T (=LMG 29572T=VKM B-3045T). We also suggest the establishment of a novel family, Gemmataceaefam. nov., which includes the phylogenetically related genera Gemmata, Zavarzinella, Telmatocola and Fimbriiglobus.

How do climate and human impact affect Sphagnum peatlands under oceanic-continental climatic conditions? 2000 years of fire and hydrological history of a bog in Northern Poland

NASA Astrophysics Data System (ADS)

Marcisz, Katarzyna; Tinner, Willy; Colombaroli, Daniele; Kołaczek, Piotr; Słowiński, Michał; Fiałkiewicz-Kozieł, Barbara; Lamentowicz, Mariusz

2014-05-01

Climate change affects many natural processes and the same applies to human impact For instance climate change and anthropogenic activities may cause increased fire activity or change peatland dynamics. Currently it is still unknown how Sphagnum peatlands in the oceanic-continental transition zone of Poland may respond to combined effects of heat waves, drought and fire. The aim of the study was to reconstruct the last 2000 years palaeohydrology and fire history at Linje bog in Northern Poland. The main task was to determine the drivers of fire episodes, particularly to identify climatic and anthropogenic forcing. A two-meter peat core was extracted and subsampled with a high resolution. Micro- and macroscopic charcoal analyses were applied to determine past fire activity and the results compared with palaeohydrological reconstructions based on testate amoeba analysis. Palynological human indicators were used to reconstruct human activity. A depth-age model including 20 14C dates was constructed to calculate peat accumulation rates and charcoal influx. We hypothesised that: 1) fire frequency in Northern Poland was determined by climatic conditions (combination of low precipitation and heat waves), as reflected in peatland water table, and that 2) past fire episodes in the last millennium were intensified by human activity. Furthermore climate may have influenced human activity over harvest success and the carrying capacity. Our study shows that fire was important for the studied ecosystem, however, its frequency has increased in the last millennium in concomitance with land use activities. Landscape humanization and vegetation opening were followed by a peatland drying during the Little Ice Age (from ca. AD 1380). Similarly to other palaeoecological studies from Poland, Linje peatland possessed an unstable hydrology during the Little Ice Age. Increased fire episodes appeared shortly before the Little Ice Age and most severe fires were present in the time when recorded water table was the lowest. We acknowledge the support of RE-FIRE SCIEX project 12.286 and grant PSPB-013/2010 from Switzerland through the Swiss Contribution to the enlarged European Union.

Rhodoblastus sphagnicola sp. nov., a novel acidophilic purple non-sulfur bacterium from Sphagnum peat bog.

PubMed

Kulichevskaya, Irina S; Guzev, Vladimir S; Gorlenko, Vladimir M; Liesack, Werner; Dedysh, Svetlana N

2006-06-01

An isolate of purple non-sulfur bacteria was obtained from an acidic Sphagnum peat bog and designated strain RS(T). The colour of cell suspensions of this bacterium growing in the light under anaerobic conditions is purplish red. Cells of strain RS(T) are rod-shaped, 0.8-1.0 microm wide and 2.0-6.0 microm long, motile by means of polar flagella, reproduce by budding and have a tendency to form rosette-like clusters in older cultures. The cells contain lamellar intracytoplasmic membranes underlying, and parallel to, the cytoplasmic membrane. The photosynthetic pigments are bacteriochlorophyll a and carotenoids; the absorption spectrum of living cells shows maxima at 377, 463, 492, 527, 592, 806 and 867 nm. The cells grow photoheterotrophically under anaerobic or microaerobic conditions with various organic carbon sources or grow photolithoautotrophically with H(2) and CO(2). Strain RS(T) is a moderately acidophilic organism exhibiting growth at pH values between 4.8 and 7.0 (with an optimum at pH 5.2-5.5). The major fatty acids are 16 : 1omega7c and 18 : 1omega7c; the major quinones are Q-10 and Q-9. The DNA G + C content of strain RS(T) is 62.6 mol%. Analysis of the 16S rRNA gene sequence revealed that the novel isolate is most closely related (97.3 % sequence similarity) to the type strain ATCC 25092(T) of the moderately acidophilic purple non-sulfur bacterium Rhodoblastus acidophilus, formerly named Rhodopseudomonas acidophila. However, in contrast to Rbl. acidophilus, strain RS(T) is not capable of aerobic growth in the dark, has no spirilloxanthin among the carotenoids and differs in the pattern of substrate utilization. The value for DNA-DNA hybridization between strain RS(T) and Rbl. acidophilus ATCC 25092(T) is only 22 %. Thus, strain RS(T) represents a novel species of the genus Rhodoblastus, for which the name Rhodoblastus sphagnicola sp. nov. is proposed. Strain RS(T) (=DSM 16996(T) = VKM B-2361(T)) is the type strain.

Geophysical characterization of peatlands using crosshole GPR full-waveform inversion: Case study from a bog in northwestern Germany

NASA Astrophysics Data System (ADS)

Schmäck, J.; Klotzsche, A.; Van Der Kruk, J.; Vereecken, H.; Bechtold, M.

2017-12-01

The characterization of peatlands is of particular interest, since areas with peat soils represent global hotspots for the exchange of greenhouse gases. Their effect on global warming depends on several parameters, like mean annual water level and land use. Models of greenhouse gas emissions and carbon accumulation in peatlands can be improved by including small-scale soil properties that e.g. act as gas traps and periodically release gases to the atmosphere during ebullition events. Ground penetrating radar (GPR) is well suited to non- or minimal invasively characterize and improve our understanding of dynamic processes that take place in the critical zone. It uses high frequency electromagnetic waves to image and characterize the dielectric permittivity and electrical conductivity of the critical zone, which can be related to hydrogeological properties like porosity, soil water content, salinity and clay content. In the last decade, the full-waveform inversion of crosshole GPR data has proved to be a powerful tool to improve the image resolution compared to standard ray-based methods. This approach was successfully applied to several different aquifers and was able to provide decimeter-scale resolution images including small-scale high contrast layers that can be related to zones of high porosity, zones of preferential flow or clay lenses. The comparison to independently measured e.g. logging data proved the reliability of the method. Here, for the first time crosshole GPR full-waveform inversion is used to image three peatland plots with different land use that are part of the "Ahlen-Falkenberger Moor peat bog complex" in northwestern Germany. The full-waveform inversion of the acquired data returned higher resolution images than standard ray-based GPR methods, and, is able to improve our understanding of subsurface structures. The comparison of the different plots is expected to provide new insights into gas content and gas trapping structures across different land uses. Additionally, season-related changes of peatland soil properties are investigated. The crosshole GPR full-waveform inversion was successfully applied to several datasets and the results show the utility and credibility of GPR FWI to analyze peatland properties.

Comparing and improving reconstruction methods for proxies based on compositional data

NASA Astrophysics Data System (ADS)

Nolan, C.; Tipton, J.; Booth, R.; Jackson, S. T.; Hooten, M.

2017-12-01

Many types of studies in paleoclimatology and paleoecology involve compositional data. Often, these studies aim to use compositional data to reconstruct an environmental variable of interest; the reconstruction is usually done via the development of a transfer function. Transfer functions have been developed using many different methods. Existing methods tend to relate the compositional data and the reconstruction target in very simple ways. Additionally, the results from different methods are rarely compared. Here we seek to address these two issues. First, we introduce a new hierarchical Bayesian multivariate gaussian process model; this model allows for the relationship between each species in the compositional dataset and the environmental variable to be modeled in a way that captures the underlying complexities. Then, we compare this new method to machine learning techniques and commonly used existing methods. The comparisons are based on reconstructing the water table depth history of Caribou Bog (an ombrotrophic Sphagnum peat bog in Old Town, Maine, USA) from a new 7500 year long record of testate amoebae assemblages. The resulting reconstructions from different methods diverge in both their resulting means and uncertainties. In particular, uncertainty tends to be drastically underestimated by some common methods. These results will help to improve inference of water table depth from testate amoebae. Furthermore, this approach can be applied to test and improve inferences of past environmental conditions from a broad array of paleo-proxies based on compositional data

Atmospheric methane sources - Alaskan tundra bogs, an alpine fen, and a subarctic boreal marsh

NASA Technical Reports Server (NTRS)

Sebacher, D. I.; Harriss, R. C.; Grice, S. S.; Bartlett, K. B.; Sebacher, S. M.

1986-01-01

Methane (CH4) flux measurements from Alaska tundra bogs, an alpine fen, and a subarctic boreal marsh were obtained at field sites ranging from Prudhoe Bay on the coast of the Arctic Ocean to the Alaskan Range south of Fairbanks during August 1984. In the tundra, average CH4 emission rates varied from 4.9 mg CH4 per sq m per day (moist tundra) to 119 mg CH4 per sq m per day (waterlogged tundra). Fluxes averaged 40 mg CH4 per sq m per day from wet tussock meadows in the Brooks Range and 289 mg Ch4 per sq m per day from an alpine fen in the Alaskan Range. The boreal marsh had an average CH4 emission rate of 106 mg CH4 per sq m per day. Significant emissions were detected in tundra areas where peat temperatures were as low as 4 C, and permafrost was only 25 cm below the ground surface. Emission rates from the 17 sites sampled were found to be logarithmically related to water levels at the sites. Extrapolation of the data to an estimate of the total annual CH4 emission from all arctic and boreal wetlands suggests that these ecosystems are a major source of atmospheric CH4 and could account for up to 23 percent of global CH4 emissions from wetlands.

Occurrence of organic arsenic species in a 4-m deep free-floating mire

NASA Astrophysics Data System (ADS)

Lobianco, Daniela; Zaccone, Claudio; Raber, Georg; D'Orazio, Valeria; Miano, Teodoro; Francesconi, Kevin

2017-04-01

Wetlands play a key role in the fate of major and trace elements, affecting their environmental mobility and ecotoxicity. Arsenic (As) is a chalcophile element that is recognized as a serious health risk worldwide. Inorganic forms of this metalloid are dominant in soils, whereas the organic forms generally occur only in trace amounts. Nevertheless, methylation processes are responsible for the mobilization of As in several ecosystems, especially in anoxic conditions. Peat cores from ombrotrophic bogs have been used to determine atmospheric depositional fluxes of total As over centuries, although the contribution of organic vs inorganic As species has been rarely considered. Here, 47 peat samples collected throughout a 400-cm deep, free-floating mire have been analysed for total As and for its organic species, including dimethylarsinic acid (DMA), methylarsonic acid (MA), trimethylarsine oxide (TMAO) and arsenobetaine (AB) by HPLC-ICP-MS. Total As concentration throughout the profile ranged between 0.20 and 9.79 mg/kg (1.41±1.36 mg/kg; mean ± st. dev.), showing values that are quite low compared to other mire ecosystems. Organic As species (DMA+MA+TMAO+AB) account, on average, for 28±10% of total As (range 6-47%; median 28%), and for 41±14% of the extracted As (range 7-73%; median 42%). The relative abundance of organoarsenicals generally followed the order DMA>TMAO˜MA>>AB, and was not correlated with main physical and chemical properties of peat, including its degree of decomposition. There was, however, a highly significant (p <0.001) statistical correlation among all organic As compounds. This result provides new insights into the occurrence of organic As species in floating mires, suggesting a possible common biological pathway for their formation.

Peat Bog Wildfire Smoke Exposure in Rural North Carolina Is Associated with Cardiopulmonary Emergency Department Visits Assessed through Syndromic Surveillance

PubMed Central

Stone, Susan L.; Cascio, Wayne E.; Neas, Lucas M.; Kilaru, Vasu J.; Carraway, Martha Sue; Szykman, James J.; Ising, Amy; Cleve, William E.; Meredith, John T.; Vaughan-Batten, Heather; Deyneka, Lana; Devlin, Robert B.

2011-01-01

Background: In June 2008, burning peat deposits produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina. Although the association of mortality and morbidity with exposure to urban air pollution is well established, the health effects associated with exposure to wildfire emissions are less well understood. Objective: We investigated the effects of exposure on cardiorespiratory outcomes in the population affected by the fire. Methods: We performed a population-based study using emergency department (ED) visits reported through the syndromic surveillance program NC DETECT (North Carolina Disease Event Tracking and Epidemiologic Collection Tool). We used aerosol optical depth measured by a satellite to determine a high-exposure window and distinguish counties most impacted by the dense smoke plume from surrounding referent counties. Poisson log-linear regression with a 5-day distributed lag was used to estimate changes in the cumulative relative risk (RR). Results: In the exposed counties, significant increases in cumulative RR for asthma [1.65 (95% confidence interval, 1.25–2.1)], chronic obstructive pulmonary disease [1.73 (1.06–2.83)], and pneumonia and acute bronchitis [1.59 (1.07–2.34)] were observed. ED visits associated with cardiopulmonary symptoms [1.23 (1.06–1.43)] and heart failure [1.37 (1.01–1.85)] were also significantly increased. Conclusions: Satellite data and syndromic surveillance were combined to assess the health impacts of wildfire smoke in rural counties with sparse air-quality monitoring. This is the first study to demonstrate both respiratory and cardiac effects after brief exposure to peat wildfire smoke. PMID:21705297

Peat bog wildfire smoke exposure in rural North Carolina is associated with cardiopulmonary emergency department visits assessed through syndromic surveillance.

PubMed

Rappold, Ana G; Stone, Susan L; Cascio, Wayne E; Neas, Lucas M; Kilaru, Vasu J; Carraway, Martha Sue; Szykman, James J; Ising, Amy; Cleve, William E; Meredith, John T; Vaughan-Batten, Heather; Deyneka, Lana; Devlin, Robert B

2011-10-01

In June 2008, burning peat deposits produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina. Although the association of mortality and morbidity with exposure to urban air pollution is well established, the health effects associated with exposure to wildfire emissions are less well understood. We investigated the effects of exposure on cardiorespiratory outcomes in the population affected by the fire. We performed a population-based study using emergency department (ED) visits reported through the syndromic surveillance program NC DETECT (North Carolina Disease Event Tracking and Epidemiologic Collection Tool). We used aerosol optical depth measured by a satellite to determine a high-exposure window and distinguish counties most impacted by the dense smoke plume from surrounding referent counties. Poisson log-linear regression with a 5-day distributed lag was used to estimate changes in the cumulative relative risk (RR). In the exposed counties, significant increases in cumulative RR for asthma [1.65 (95% confidence interval, 1.25-2.1)], chronic obstructive pulmonary disease [1.73 (1.06-2.83)], and pneumonia and acute bronchitis [1.59 (1.07-2.34)] were observed. ED visits associated with cardiopulmonary symptoms [1.23 (1.06-1.43)] and heart failure [1.37 (1.01-1.85)] were also significantly increased. Satellite data and syndromic surveillance were combined to assess the health impacts of wildfire smoke in rural counties with sparse air-quality monitoring. This is the first study to demonstrate both respiratory and cardiac effects after brief exposure to peat wildfire smoke.

Impact of Peat Mining and Restoration on Methane Turnover Potential and Methane-Cycling Microorganisms in a Northern Bog.

PubMed

Reumer, Max; Harnisz, Monika; Lee, Hyo Jung; Reim, Andreas; Grunert, Oliver; Putkinen, Anuliina; Fritze, Hannu; Bodelier, Paul L E; Ho, Adrian

2018-02-01

Ombrotrophic peatlands are a recognized global carbon reservoir. Without restoration and peat regrowth, harvested peatlands are dramatically altered, impairing their carbon sink function, with consequences for methane turnover. Previous studies determined the impact of commercial mining on the physicochemical properties of peat and the effects on methane turnover. However, the response of the underlying microbial communities catalyzing methane production and oxidation have so far received little attention. We hypothesize that with the return of Sphagnum spp. postharvest, methane turnover potential and the corresponding microbial communities will converge in a natural and restored peatland. To address our hypothesis, we determined the potential methane production and oxidation rates in natural (as a reference), actively mined, abandoned, and restored peatlands over two consecutive years. In all sites, the methanogenic and methanotrophic population sizes were enumerated using quantitative PCR (qPCR) assays targeting the mcrA and pmoA genes, respectively. Shifts in the community composition were determined using Illumina MiSeq sequencing of the mcrA gene and a pmoA -based terminal restriction fragment length polymorphism (t-RFLP) analysis, complemented by cloning and sequence analysis of the mmoX gene. Peat mining adversely affected methane turnover potential, but the rates recovered in the restored site. The recovery in potential activity was reflected in the methanogenic and methanotrophic abundances. However, the microbial community composition was altered, being more pronounced for the methanotrophs. Overall, we observed a lag between the recovery of the methanogenic/methanotrophic activity and the return of the corresponding microbial communities, suggesting that a longer duration (>15 years) is needed to reverse mining-induced effects on the methane-cycling microbial communities. IMPORTANCE Ombrotrophic peatlands are a crucial carbon sink, but this environment is also a source of methane, an important greenhouse gas. Methane emission in peatlands is regulated by methane production and oxidation catalyzed by methanogens and methanotrophs, respectively. Methane-cycling microbial communities have been documented in natural peatlands. However, less is known of their response to peat mining and of the recovery of the community after restoration. Mining exerts an adverse impact on potential methane production and oxidation rates and on methanogenic and methanotrophic population abundances. Peat mining also induced a shift in the methane-cycling microbial community composition. Nevertheless, with the return of Sphagnum spp. in the restored site after 15 years, methanogenic and methanotrophic activity and population abundance recovered well. The recovery, however, was not fully reflected in the community composition, suggesting that >15 years are needed to reverse mining-induced effects. Copyright © 2018 American Society for Microbiology.

The use of plant-specific pyrolysis products as biomarkers in peat deposits

NASA Astrophysics Data System (ADS)

Schellekens, Judith; Bradley, Jonathan A.; Kuyper, Thomas W.; Fraga, Isabel; Pontevedra-Pombal, Xabier; Vidal-Torrado, Pablo; Abbott, Geoffrey D.; Buurman, Peter

2015-09-01

Peatlands are archives of environmental change that can be driven by climate and human activity. Proxies for peatland vegetation composition provide records of (local) environmental conditions that can be linked to both autogenic and allogenic factors. Analytical pyrolysis offers a molecular fingerprint of peat, and thereby a suite of environmental proxies. Here we investigate analytical pyrolysis as a method for biomarker analysis. Pyrolysates of 48 peatland plant species were compared, comprising seventeen lichens, three Sphagnum species, four non-Sphagnum mosses, eleven graminoids (Cyperaceae, Juncaceae, Poaceae), five Ericaceae and six species from other families. This resulted in twenty-one potential biomarkers, including new markers for lichens (3-methoxy-5-methylphenol) and graminoids (ferulic acid methyl ester). The potential of the identified biomarkers to reconstruct vegetation composition is discussed according to their depth records in cores from six peatlands from boreal, temperate and tropical biomes. The occurrence of markers for Sphagnum, graminoids and lichens in all six studied peat deposits indicates that they persist in peat of thousands of years old, in different vegetation types and under different conditions. In order to facilitate the quantification of biomarkers from pyrolysates, typically expressed as proportion (%) of the total quantified pyrolysis products, an internal standard (5-α-androstane) was introduced. Depth records of the Sphagnum marker 4-isopropenylphenol from the upper 3 m of a Sphagnum-dominated peat, from samples analysed with and without internal standard showed a strong positive correlation (r2 = 0.72, P < 0.0005, n = 12). This indicates that application of an internal standard is a reliable method to assess biomarker depth records, which enormously facilitates the use of analytical pyrolysis in biomarker research by avoiding quantification of a high number of products.

The role of Juncus effusus litter quality and nutrient availability on organic matter decomposition in restored cutover bogs

NASA Astrophysics Data System (ADS)

Agethen, Svenja; Knorr, Klaus-Holger

2017-04-01

More than 90% of peatlands in Europe are degraded by drainage and subsequent land use. However, beneficial effects of functioning peatlands, most of all carbon storage, have long been recognized but remain difficult to recover. Fragmentation and a surrounding of intensively used agricultural catchments with excess nutrients in air and waters further affects the recovery of sites. Under such conditions, highly competitive species such as Juncus effusus colonize restored peatlands instead of peat forming Sphagnum. While the specific stoichiometry and chemical composition makes Sphagnum litter recalcitrant in decomposition and hence, effective in carbon sequestration, we know little about dynamics involving Juncus, although this species provides organic matter in high quantity and of rather labile quality. To better understand decomposition in context of litter quality and nutrient availability, we incubated different peat types for 70 days; I) recent, II) weakly degraded fossil, and III) earthyfied nutrient rich fossil peat, amended with two 13C pulse-labelled Juncus litter types (excessively fertilized "F", and nutrient poor "NF" plants grown for three years watered with MilliQ only), respectively. We determined anaerobic decomposition rates, compared potential rates extrapolated from pure materials with measured rates of the mixtures, and tracked the 13C in the solid, liquid, and gaseous phase. To characterize the biogeochemical conditions, inorganic and organic electron acceptors, hydrogen and organic acids, and total enzyme activity were monitored. For characterization of dissolved organic matter we used UV-Vis and fluorescence spectroscopy (parallel factor analysis), and for solid organic matter elemental analysis and FTIR spectroscopy. There were two main structural differences between litter types: "F" litter and its leachates contained more proteinaceous components, the C/N ratio was 20 in contrast to 60 of the "NF" litter. However, humic components and aromaticity were higher in "F" litter. Generally, decomposition rates of litter were 5-30 times higher than of peat. Rates in batches amended with "F" were lower compared to "NF" for the respective peat, opposing typically reported observations. Nevertheless, the 13C label suggested that in case of peat I and III preferably the litter was decomposed, decomposition of peat II was apparently stimulated when "NF" was added, albeit this litter was poor in nutrients. Multiple linear regression identified specific absorption at 254 nm (SUVA), a measure of aromaticity representative for an array of inter-correlating spectroscopic features, and enzyme activity as most important predictors for C-mineralization rates. These two parameters explained 88% of the variance. Although enzyme activity and SUVA did not correlate in the mixed assays, this was the case for the pure materials (R2=0.95), suggesting an inhibitory effect of aromatic components on enzyme activity. This study confirms that generally litter quality is a major control for mineralization and hence, carbon storage in peatlands. Interestingly, in the case of Juncus effusus, high nutrient availability in peat and litter did not lead to enhanced degradation of the litter itself or priming of decomposition of the surrounding peat. Furthermore, the results underline the substantial contribution of Juncus biomass to C-cycling and potentially high C-emissions in restored peatlands.

An introduction to the Australian and New Zealand flux tower network - OzFlux

NASA Astrophysics Data System (ADS)

Beringer, Jason; Hutley, Lindsay B.; McHugh, Ian; Arndt, Stefan K.; Campbell, David; Cleugh, Helen A.; Cleverly, James; Resco de Dios, Víctor; Eamus, Derek; Evans, Bradley; Ewenz, Cacilia; Grace, Peter; Griebel, Anne; Haverd, Vanessa; Hinko-Najera, Nina; Huete, Alfredo; Isaac, Peter; Kanniah, Kasturi; Leuning, Ray; Liddell, Michael J.; Macfarlane, Craig; Meyer, Wayne; Moore, Caitlin; Pendall, Elise; Phillips, Alison; Phillips, Rebecca L.; Prober, Suzanne M.; Restrepo-Coupe, Natalia; Rutledge, Susanna; Schroder, Ivan; Silberstein, Richard; Southall, Patricia; Yee, Mei Sun; Tapper, Nigel J.; van Gorsel, Eva; Vote, Camilla; Walker, Jeff; Wardlaw, Tim

2016-10-01

OzFlux is the regional Australian and New Zealand flux tower network that aims to provide a continental-scale national research facility to monitor and assess trends, and improve predictions, of Australia's terrestrial biosphere and climate. This paper describes the evolution, design, and current status of OzFlux as well as provides an overview of data processing. We analyse measurements from all sites within the Australian portion of the OzFlux network and two sites from New Zealand. The response of the Australian biomes to climate was largely consistent with global studies except that Australian systems had a lower ecosystem water-use efficiency. Australian semi-arid/arid ecosystems are important because of their huge extent (70 %) and they have evolved with common moisture limitations. We also found that Australian ecosystems had a similar radiation-use efficiency per unit leaf area compared to global values that indicates a convergence toward a similar biochemical efficiency. The two New Zealand sites represented extremes in productivity for a moist temperate climate zone, with the grazed dairy farm site having the highest GPP of any OzFlux site (2620 gC m-2 yr-1) and the natural raised peat bog site having a very low GPP (820 gC m-2 yr-1). The paper discusses the utility of the flux data and the synergies between flux, remote sensing, and modelling. Lastly, the paper looks ahead at the future direction of the network and concludes that there has been a substantial contribution by OzFlux, and considerable opportunities remain to further advance our understanding of ecosystem response to disturbances, including drought, fire, land-use and land-cover change, land management, and climate change, which are relevant both nationally and internationally. It is suggested that a synergistic approach is required to address all of the spatial, ecological, human, and cultural challenges of managing the delicately balanced ecosystems in Australasia.

Intermediate-scale community-level flux of CO 2 and CH 4 in a Minnesota peatland: Putting the SPRUCE project in a global context

DOE PAGES

Hanson, Paul J.; Gill, Allison; Xu, Xiaofeng; ...

2016-08-20

Peatland measurements of CO 2 and CH 4 flux were obtained at scales appropriate to the in situ biological community below the tree layer to demonstrate representativeness of the spruce and peatland responses under climatic and environmental change (SPRUCE) experiment. Surface flux measurements were made using dual open-path analyzers over an area of 1.13 m 2 in daylight and dark conditions along with associated peat temperatures, water table height, hummock moisture, atmospheric pressure and incident radiation data. Observations from August 2011 through December 2014 demonstrated seasonal trends correlated with temperature as the dominant apparent driving variable. The S1-Bog for themore » SPRUCE study was found to be representative of temperate peatlands in terms of CO 2 and CH 4 flux. Maximum net CO 2 flux in midsummer showed similar rates of C uptake and loss: daytime surface uptake was -5 to -6 µmol m -2 s -1 and dark period loss rates were 4–5 µmol m -2 s -1 (positive values are carbon lost to the atmosphere). Maximum midsummer CH4-C flux ranged from 0.4 to 0.5 µmol m -2 s -1 and was a factor of 10 lower than dark CO 2–C efflux rates. Midwinter conditions produced near-zero flux for both CO 2 and CH 4 with frozen surfaces. Integrating temperature-dependent models across annual periods showed dark CO 2–C and CH 4–C flux to be 894 ± 34 and 16 ± 2 gC m -2 y -1, respectively. Net ecosystem exchange of carbon from the shrub-forb-Sphagnum-microbial community (excluding tree contributions) ranged from -3.1 gCO2–C m -2 y -1 in 2013, to C losses from 21 to 65 gCO 2–C m -2 y -1 for the other years.« less

Holocene Vegetation Changes in Eastern Kamchatka Based on Pollen and Macrofossil Records

NASA Astrophysics Data System (ADS)

Dirksen, V.

2004-12-01

Little is known about the Quaternary climate and vegetation history of Kamchatka. Only a few previous studies have provided paleoenvironmental information for this area, but these studies have poor age control and are inconsistent To reconstruct paleoclimate and both regional and local vegetation history we are analyzing continuous, high-resolution pollen and macrofossil records from peats on Kamchatka. Thin, well-dated ash layers in these peats provide excellent age control; sections sampled thus far range in age back to 12,000 years. Herein we report results from one example, the Uka peat section (57.8oN 162.2oE; about 10 m a.s.l.). This section is located on a morainal terrace close to a small lake. The basal section is lacustrine clay with a few spores pointing to scarce vegetation under cold conditions, probably latest Pleistocene. This clay is replaced upward by limnic peat, probably early Holocene (pollen zone 1). This zone is characterized by dominance of shrub alder and birch, herbs, and ferns. The highest value (in the whole section) of sage and the absence of tree pollen suggest a treeless landscape and thin vegetation cover under still cold conditions, while increase in local aquatic pollen indicates lake filling and shrinking. In Zone 2 (ca. 8000-4000 BP), mire vegetation shows successive development of eutrophic fen including three pulses of sphagnum followed by sedge peaks. Pollen concentration is very low, probably indicating high deposition rates. A warming trend is suggested by the appearance ca. 5600 BP of tree birch, increasing to the end of zone 2, while alder strongly decreases. The most pronounced changes in both regional and local vegetation are found ca. 3800 BP, when tree birch pollen reaches its highest value and a few long-transported spruce pollen grains appear. The dominant (eutrophic) sedge is suddenly replaced by a more oligotrophic one. Such local components as grasses, shrub birch and willow increase, and total pollen concentration dramatically increases. All these features suggest drier conditions in zone 3 (3800-1200 BP), however it should be supported by further studies. Zone 4 (1200 BP to present) shows development of an oligotrophic peat bog indicated by high values of heath; the establishment of shrub pine is signaled by a sharp increase in its pollen.

Phase of Target Scattering for Wetland Characterization using Polarimetric C-Band SAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Touzi, R; Deschamps, Mireille C; Rother, Gernot

2009-09-01

Wetlands continue to be under threat, and there is a major need for mapping and monitoring wetlands for better management and protection of these sensitive areas. Only a few studies have been published on wetland characterization using polarimetric synthetic aperture radars (SARs). The most successful results have been obtained using the phase difference between HH and VV polarizations, phi{sub HH} - phi{sub VV}, which has shown promise for separating flooded wetland classes. Recently, we have introduced a new decomposition, the Touzi decomposition, which describes target scattering type in terms of a complex entity, the symmetric scattering type. Huynen's target helicitymore » is used to assess the symmetric nature of target scattering. In this paper, the new complex-scattering-type parameters, the magnitude alphas and phase Phi{sub alpha} s, are investigated for wetland characterization. The use of the dominant-scattering-type phase Phi{sub alpha} s makes it possible to discriminate shrub bogs from poor (sedge or shrub) fens. These two classes cannot be separated using phi{sub HH} - phi{sub VV}, or the radiometric scattering information provided by alphas, the Cloude alpha, the entropy H, and the multipolarization HH-HV-VV channels. phi{sub alpha} s, which cannot detect deep (45 cm below the peat surface) water flow in a bog, is more sensitive to the shallower (10-20-cm) fen beneath water, and this makes possible the separation of poor fens from shrub bogs. Phi{sub alpha} s also permits the discrimination of conifer-dominated treed bog from upland deciduous forest under leafy conditions. Target helicity information is exploited to introduce a new parameter, the target asymmetry. The latter is shown very promising for detection of forest changes between leafy and no-leaf conditions. The analysis of low-entropy marsh scattering showed that both the scattering-type magnitude and phas- - e alphas and Phi{sub alpha} s, respectively, as well as the maximum polarization intensity of the dominant scattering m, are needed for a better understanding of marsh complex scattering mechanisms. The unique information provided by the new roll-invariant decomposition parameters are demonstrated using repeat-pass Convair-580 polarimetric C-band SAR data collected in June and October 1995 over the RAMSAR Mer Bleue wetland site near Ottawa (Canada).« less

DOC export from a peat extraction site in transition to managed restoration - preliminary results of a long-term research project

NASA Astrophysics Data System (ADS)

Rüggen, Norman; Kutzbach, Lars; Kopelke, Susanne; Pfeiffer, Eva-Maria

2013-04-01

Peatlands play a major role in the global cycles of water and carbon. Budgeting carbon fluxes of temperate man-managed peatlands is limited by few available data. The main carbon compounds exported from such sites are CO2, CH4 and laterally exported C compounds (dissolved organic carbon (DOC) and gases). Without reliable estimates of laterally exported carbon from managed peatlands, overall carbon balances of such geoecosystems remain obscure. The Himmelmoor peatland in Schleswig-Holstein is subject to horticultural peat extraction in transition towards managed restoration. One-third of 130 ha of peatland area are already subject to managed restoration, the remaining part is still intensively used as a peat extraction site. Surface water discharge rates are measured by a water head sensor in combination with a rectangular-shaped weir. An October-November data set (54 days period, 2012) shows a distinct base-flow and precipitation-dependent discharge peaks, which were up to five times higher than the base-flow. The observations indicate a poor water storing capacity of the intensively used areas. During this first observation period, almost 65,000 tons of peatland-DOC-bearing water have been discharged into the adjacent river system. DOC concentrations in the discharge water have been measured every 6-12 days with a Total Carbon Analyzer TOC-L (Shimadzu, Japan). Additionally, a field spectrophotometer (spectro::lyser,s-can, Austria) has been employed, for measuring quasi-continuous concentrations of DOC. During the 54 day period, approximately 1.75 g DOC m-2 (or about 1750 kg DOC km-2) has been laterally exported from the peatland. Average DOC concentration was 35.1 ± 4 g l-1. These values range in the same order of magnitude that have been published from managed UK peatlands (Armstrong et al., 2010; Wilson et al., 2011). Preliminary data evaluation of the in-situ field spectrophotometer show that DOC concentrations of discharge water varied up to 1.5 mg L-1 in less than six hours and up to about 3 mg L-1 in 36 hours. The described recently established hydrological measurements are planned to be continued for the next ten years in combination with continuous eddy covariance measurements of land-atmosphere fluxes of Water, CO2 and CH4. This long-term monitoring of lateral and vertical exchange fluxes will serve as a basis for evaluating the success of the peatland restoration with respect to biogeochemical cycling and greenhouse gas budgets. Literature Armstrong, A., Holden, J., Kay, P., Francis, B., Foulger, M., Gledhill, S., McDonald, A., Walker, A., 2010. The impact of peatland drain-blocking on dissolved organic carbon loss and discolouration of water; results from a national survey. Journal of Hydrology 381, 112-120. Wilson, L., Wilson, J., Holden, J., Johnstone, I., Armstrong, A., Morris, M., 2011. Ditch blocking, water chemistry and organic carbon flux: Evidence that blanket bog restoration reduces erosion and fluvial carbon loss. Science of the Total Environment 409, 2010-2018.

Carbon balance of a drained forested bog in southern Finland

NASA Astrophysics Data System (ADS)

Minkkinen, Kari; Penttilä, Timo; Ojanen, Paavo; Lohila, Annalea

2016-04-01

Carbon and greenhouse gas (GHG) dynamics of a drained forested peatland in southern Finland were measured over multiple years, including one with severe drought during growing season. Net ecosystem carbon dioxide exchange (NEE) was measured with an eddy covariance method from a tower above the forest. Soil and forest floor CO2, CH4 and N2O fluxes were measured from the strips and from ditches with closed chambers. Biomasses and litter production were sampled, and soil subsidence was measured by consequtive levelings of the peat surface. The data were used to estimate the ecosystem C pools and annual fluxes of carbon and GHGs of the peatland and to analyse the impact of periodical drought on the carbon fluxes. The drained peatland was a strong sink of carbon dioxide in all studied years. Soil CO2 balance was estimated by subtracting the carbon sink of the growing tree stand from NEE, and it showed that also the soil was a sink of carbon in all studied years. A drought period in one summer significantly decreased the sink through decreased GPP. Drought also decreased the ecosystem respiration, including soil respiration. Decreasing water table thus did not increase, but rather decreased CO2 efflux from the peat soil. The site was a small sink for CH4, even when emissions from ditches were included. N2O emissions were small from all surfaces. Despite of the continuous carbon sink, peat surface subsided slightly (1.4 mm a-1) during the 10-year measurement period, which is interpreted to mean mainly compaction, rather than oxidation of the peat. It is concluded that this drained peatland acts as a continuous soil C sink similarly to an undrained peatland. The reason may be the relatively small water-level drawdown compared to an undrained situation, the consequently rather small changes in plant community structure and the significantly improved tree stand growth and litter production. The consequences of continuing production forestry vs. restoration of the site on the GHG fluxes and climate impact will be discussed.

Genome Analysis of Fimbriiglobus ruber SP5T, a Planctomycete with Confirmed Chitinolytic Capability.

PubMed

Ravin, Nikolai V; Rakitin, Andrey L; Ivanova, Anastasia A; Beletsky, Alexey V; Kulichevskaya, Irina S; Mardanov, Andrey V; Dedysh, Svetlana N

2018-04-01

Members of the bacterial order Planctomycetales have often been observed in associations with Crustacea. The ability to degrade chitin, however, has never been reported for any of the cultured planctomycetes although utilization of N -acetylglucosamine (GlcNAc) as a sole carbon and nitrogen source is well recognized for these bacteria. Here, we demonstrate the chitinolytic capability of a member of the family Gemmataceae , Fimbriiglobus ruber SP5 T , which was isolated from a peat bog. As revealed by metatranscriptomic analysis of chitin-amended peat, the pool of 16S rRNA reads from F. ruber increased in response to chitin availability. Strain SP5 T displayed only weak growth on amorphous chitin as a sole source of carbon but grew well with chitin as a source of nitrogen. The genome of F. ruber SP5 T is 12.364 Mb in size and is the largest among all currently determined planctomycete genomes. It encodes several enzymes putatively involved in chitin degradation, including two chitinases affiliated with the glycoside hydrolase (GH) family GH18, GH20 family β- N -acetylglucosaminidase, and the complete set of enzymes required for utilization of GlcNAc. The gene encoding one of the predicted chitinases was expressed in Escherichia coli , and the endochitinase activity of the recombinant enzyme was confirmed. The genome also contains genes required for the assembly of type IV pili, which may be used to adhere to chitin and possibly other biopolymers. The ability to use chitin as a source of nitrogen is of special importance for planctomycetes that inhabit N-depleted ombrotrophic wetlands. IMPORTANCE Planctomycetes represent an important part of the microbial community in Sphagnum -dominated peatlands, but their potential functions in these ecosystems remain poorly understood. This study reports the presence of chitinolytic potential in one of the recently described peat-inhabiting members of the family Gemmataceae , Fimbriiglobus ruber SP5 T This planctomycete uses chitin, a major constituent of fungal cell walls and exoskeletons of peat-inhabiting arthropods, as a source of nitrogen in N-depleted ombrotrophic Sphagnum -dominated peatlands. This study reports the chitin-degrading capability of representatives of the order Planctomycetales . Copyright © 2018 American Society for Microbiology.

High emissions of greenhouse gases from grasslands on peat and other organic soils.

PubMed

Tiemeyer, Bärbel; Albiac Borraz, Elisa; Augustin, Jürgen; Bechtold, Michel; Beetz, Sascha; Beyer, Colja; Drösler, Matthias; Ebli, Martin; Eickenscheidt, Tim; Fiedler, Sabine; Förster, Christoph; Freibauer, Annette; Giebels, Michael; Glatzel, Stephan; Heinichen, Jan; Hoffmann, Mathias; Höper, Heinrich; Jurasinski, Gerald; Leiber-Sauheitl, Katharina; Peichl-Brak, Mandy; Roßkopf, Niko; Sommer, Michael; Zeitz, Jutta

2016-12-01

Drainage has turned peatlands from a carbon sink into one of the world's largest greenhouse gas (GHG) sources from cultivated soils. We analyzed a unique data set (12 peatlands, 48 sites and 122 annual budgets) of mainly unpublished GHG emissions from grasslands on bog and fen peat as well as other soils rich in soil organic carbon (SOC) in Germany. Emissions and environmental variables were measured with identical methods. Site-averaged GHG budgets were surprisingly variable (29.2 ± 17.4 t CO 2 -eq. ha -1  yr -1 ) and partially higher than all published data and the IPCC default emission factors for GHG inventories. Generally, CO 2 (27.7 ± 17.3 t CO 2  ha -1  yr -1 ) dominated the GHG budget. Nitrous oxide (2.3 ± 2.4 kg N 2 O-N ha -1  yr -1 ) and methane emissions (30.8 ± 69.8 kg CH 4 -C ha -1  yr -1 ) were lower than expected except for CH 4 emissions from nutrient-poor acidic sites. At single peatlands, CO 2 emissions clearly increased with deeper mean water table depth (WTD), but there was no general dependency of CO 2 on WTD for the complete data set. Thus, regionalization of CO 2 emissions by WTD only will remain uncertain. WTD dynamics explained some of the differences between peatlands as sites which became very dry during summer showed lower emissions. We introduced the aerated nitrogen stock (N air ) as a variable combining soil nitrogen stocks with WTD. CO 2 increased with N air across peatlands. Soils with comparatively low SOC concentrations showed as high CO 2 emissions as true peat soils because N air was similar. N 2 O emissions were controlled by the WTD dynamics and the nitrogen content of the topsoil. CH 4 emissions can be well described by WTD and ponding duration during summer. Our results can help both to improve GHG emission reporting and to prioritize and plan emission reduction measures for peat and similar soils at different scales. © 2016 John Wiley & Sons Ltd.

Holocene Development of Subarctic Permafrost Peatlands in Finnmark, Northern Norway

NASA Astrophysics Data System (ADS)

Sannel, B.; Axelsson, P.; Kjellman, S.; Etzelmuller, B.; Westermann, S.

2017-12-01

Subarctic permafrost peatlands have acted as important carbon sinks throughout the Holocene. An improved knowledge of peat properties and sensitivity to past climate changes in these environments can help us better predict future responses under warmer climatic conditions, and associated permafrost carbon feedbacks. In this study analyses of plant macrofossils, bulk density, organic, carbon and nitrogen content, and AMS radiocarbon dating have been performed for four profiles collected from peat plateaus in Finnmark, northern Norway. Preliminary results suggest that peatland development started around 9800-9200 cal yr BP at the two continental sites, Suossjavri and Iskoras. Here, the long-term net carbon accumulation rates are around 12-17 gC m-2 yr-1, and the total carbon storage c. 113-156 kgC m-2. The other two sites, Lakselv and Karlebotn, are located in maritime settings close to the coast where there has been a time lag between deglaciation of the Fennoscandian Ice Sheet and emergence of land by isostatic uplift. At these sites peatland inception begun around 6200-5200 cal yr BP, and the carbon accumulation rates are c. 7-12 gC m-2 yr-1. Because of a shorter time period available for peat accumulation the carbon storage at these sites is lower, around 56-64 kgC m-2. All four peatlands developed as wet fens, and have remained permafrost-free throughout most of the Holocene. Permafrost aggradation, causing frost heave and a shift in the vegetation assemblage from wet fen to dry bog species, probably did not occur until during the onset of the Little Ice Age c. 1000-800 cal yr BP (at Iskoras and Karlebotn) or even later, around 100 cal yr BP (at Suossjavri and Lakselv). If the permafrost thaws in a future warmer climate, the carbon that has been stored in the frozen peat since the Little Ice Age can become available for decomposition and be emitted to the atmosphere either as carbon dioxide from expanding active layers or as methane from thermokarst lakes and fens.

Water table variability and runoff generation in an eroded peatland, South Pennines, UK

NASA Astrophysics Data System (ADS)

Daniels, S. M.; Agnew, C. T.; Allott, T. E. H.; Evans, M. G.

2008-10-01

SummaryHydrological monitoring in an eroded South Pennine peatland shows that persistent and frequent water table drawdowns occur at gully edge locations, defining a deeper and thicker acrotelm than is observed in intact peatlands (an erosional acrotelm). Antecedent water table elevation is a key control on the hydrological response to precipitation events, in particular runoff percent, the timing of peak discharges and maximum water table elevations. Significant discharge is generated whilst water table elevations are relatively low at gully edge locations, and this has a strong influence on flow pathways. Four characteristics of runoff response are recognised: (i) the rapid development of macropore/pipe flow at the start of the storm; (ii) peat rewetting, water table elevation increase and continued macropore/pipe flow; (iii) maximum water table elevations and peak stream discharge with throughflow occurring within the erosional acrotelm and rapid flow through the subsurface macropore/pipe network; (iv) rapidly declining water table elevations and stream flow following the cessation of rainfall. Gully edge peats provide a key linkage between the hillslope hydrological system and channel flow so that their influence on the hydrological functioning of the peatlands is disproportionate to their aerial extent within the catchment. Future climate change may lead to further degradation of the bogs and a reinforcement of the importance of erosion gullies to runoff generation and water quality.

Andromeda polifolia and Oxycoccus microcarpus as pollution indicators for ombrotrophic bogs in the Western Sudety Mountains (SW Poland).

PubMed

Wojtuń, Bronisław; Samecka-Cymerman, Aleksandra; Kolon, Krzysztof; Klink, Agnieszka; Kempers, Alexander J

2013-01-01

Concentrations of the elements Cd, Cr, Cu, Fe, Li, Mn, N, Ni, Pb and Zn in Andromeda polifolia, Oxycoccus microcarpus and in the peat in which these plants grew were measured in the Western Sudety (Karkonosze and Izerskie Mts., SW Poland). Of both the investigated plant fruit, O. microcarpus harvested from wild populations are commonly used as medicines. Samples from ombrotrophic bogs were investigated within the area influenced by exhausts of the former Black Triangle, one of the most heavily industrialized and polluted areas in Europe. A. polifolia and O. microcarpus growing at the highest elevations contained the highest Cu, Li, Ni, Mn and Zn concentrations and in addition O. microcarpus also contained the highest Cr concentrations. Both the investigated species have wide circumpolar distribution in ombrotrophic mires of the Northern hemisphere. As this type of mires is nourished solely by atmospheric deposition, the increased metal concentrations in A. polifolia and O. microcarpus may be an indication that their habitats receive an atmospheric input of long-range transported pollution. Our investigation proves that both species are able to accumulate elevated metal levels and may be used in the bioindication of the metal status in ombrotrophic mires. Controlling the collection of O. microcarpus fruit for consumption and medicinal purposes is recommended as this species can accumulate increased metal levels. However, further more detailed studies are necessary to verify the inner translocation of metals into fruit.

Characterizing Early Succession Following Wildfires at Different Severities in Boreal Bog and Fen Peatlands

NASA Astrophysics Data System (ADS)

Ernst, E. J.; Bourgeau-Chavez, L. L.; Kane, E. S.; Wagenbrenner, J. W.; Endres, S.

2016-12-01

The Arctic-boreal region is experiencing changes in climate, trending toward warmer summers, resulting in a greater occurrence of wildfires with longer burning periods and higher intensities. Drought-like conditions have dried surface fuels, leading to a higher probability of ignition, even in lowland peatlands. Previous work has been done to characterize post-fire succession rates in Arctic-boreal upland sites, but much less is known of fire effects and early successional dynamics in lowlands. Wildland fires are the number one disturbance in Canada's Northwest Territories (NWT), which characteristically burn at high intensities with large flame fronts, and result in some of the biggest wildfires in the world. Areas surrounding the Great Slave Lake, NWT—including parts of the Taiga Plains, Taiga Shield, and Boreal Plains ecozones—experienced exceptional wildfire activity in 2014 and 2015. We characterized burn severity of the bog and fen peat surface and canopy layers at several burned sites. To determine if the severe ground or crown wildfires were stand-replacing events, we characterized post-fire vegetation in peatlands in 2015 and 2016 based on seedling regeneration. We stratified sites according to estimated water residence times across the three ecozones and made comparisons between data collected at the same sites across years. This work adds much needed context for post-fire succession in boreal peatland ecosystems, as the susceptibility of these systems to burning will continue to increase with a warming climate.

A coherent high-precision radiocarbon chronology for the Late-glacial sequence at Sluggan Bog, Co. Antrim, Northern Ireland

NASA Astrophysics Data System (ADS)

Lowe, J. J.; Walker, M. J. C.; Scott, E. M.; Harkness, D. D.; Bryant, C. L.; Davies, S. M.

2004-02-01

Seventy-five radiocarbon dates are presented from Sluggan Bog in Co. Antrim, Northern Ireland. The Holocene peats are underlain by Late-glacial sediments, which also appear to have accumulated largely in a mire environment. The radiocarbon dates, from the Late-glacial and early Holocene part of the profile, were obtained from the humic and humin fractions of the sedimentary matrix, and from plant macrofossils. The last-named were dated by AMS and the sediment samples by radiometric (beta counting) methods. Age-depth models for the three dating series show a very high level of agreement between the two fractions and the macrofossils. No statistically significant difference is found between the beta counting and AMS results. Three tephras were located in the profile, the uppermost of which is in a stratigraphical position suggestive of the Vedde Ash, but the geochemical and radiocarbon evidence do not support this interpretation. The lower ashes are in the correct stratigraphical position for the Laacher See and Borrobol tephras, attributions substantiated by the radiocarbon evidence, but not by the geochemical data. The Sluggan sequence has generated one of the most internally consistent radiocarbon chronologies for any Late-glacial site in the British Isles, and it is suggested that in future more effort should be devoted to the search for, and analysis of, Late-glacial mire sequences, rather than the limnic records that have formed the principal focus of Late-glacial investigations hitherto. Copyright

Increasing summer rainfall in arid eastern-Central Asia over the past 8500 years

PubMed Central

Hong, Bing; Gasse, Françoise; Uchida, Masao; Hong, Yetang; Leng, Xuetian; Shibata, Yasuyuki; An, Ning; Zhu, Yongxuan; Wang, Yu

2014-01-01

A detailed and well-dated proxy record of summer rainfall variation in arid Central Asia is lacking. Here, we report a long-term, high resolution record of summer rainfall extracted from a peat bog in arid eastern-Central Asia (AECA). The record indicates a slowly but steadily increasing trend of summer rainfall in the AECA over the past 8500 years. On this long-term trend are superimposed several abrupt increases in rainfall on millennial timescales that correspond to rapid cooling events in the North Atlantic. During the last millennium, the hydrological climate pattern of the AECA underwent a major change. The rainfall in the past century has reached its highest level over the 8500-year history, highlighting the significant impact of the human-induced greenhouse effect on the hydrological climate in the AECA. Our results demonstrate that even in very dry eastern-Central Asia, the climate can become wetter under global warming. PMID:24923304

Vanadium in landscape components of western Transbaikalia

NASA Astrophysics Data System (ADS)

Kashin, V. K.

2017-10-01

Vanadium in soil-forming rocks, soils, and vegetation of forest-steppe, steppe, and dry-steppe landscapes of Transbaikalia has been studied. The mean element contents in rocks and soils are equal to its mean natural abundances (clarke values). The content of vanadium in soils is strictly determined by its content in parent materials; its dependence on the vanadium concentration in plants and on the soil pH and humus is less pronounced. With respect to the coefficient of biological uptake by plants, vanadium is assigned to the group of elements of slight accumulation (0.10-0.33) on mineral soils and of moderate accumulation (1.1-1.5) on peat bog soils. The mean vanadium concentration in steppe, meadow, and cultivated vegetation exceeds the norm for animals by 1.7-2.6 times but does not rich toxic levels. Vanadium uptake by plants is most intensive in meadow cenoses and is less intensive in dry-steppe cenoses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pati, Amrita; Sikorski, Johannes; Nolan, Matt

Saccharomonospora viridis (Schuurmans et al. 1956) Nonomurea and Ohara 1971 is the type species of the genus Saccharomonospora which belongs to the family Pseudonocardiaceae. S. viridis is of interest because it is a Gram-negative organism classified amongst the usually Gram-positive actinomycetes. Members of the species are frequently found in hot compost and hay, and its spores can cause farmer?s lung disease, bagassosis, and humidifier fever. Strains of the species S. viridis have been found to metabolize the xenobiotic pentachlorophenol (PCP). The strain described in this study has been isolated from peat-bog in Ireland. Here we describe the features of thismore » organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of the family Pseudonocardiaceae, and the 4,308,349 bp long single replicon genome with its 3906 protein-coding and 64 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.« less

Less-studied TCE: are their environmental concentrations increasing due to their use in new technologies?

PubMed

Filella, M; Rodríguez-Murillo, J C

2017-09-01

The possible environmental impact of the recent increase in use of a group of technology-critical elements (Nb, Ta, Ga, In, Ge and Te) is analysed by reviewing published concentration profiles in environmental archives (ice cores, ombrotrophic peat bogs, freshwater sediments and moss surveys) and evaluating temporal trends in surface waters. No increase has so far been recorded. The low potential direct emissions of these elements, resulting from their absolute low production levels, make it unlikely that the increasing use of these elements in modern technology has any noticeable effect on their environmental concentrations on a global scale. This holds particularly true for those of these elements that are probably emitted in relatively high amounts from other human activities (i.e., coal combustion and non-ferrous smelting), such as In, the most studied element of the group. Copyright © 2017 Elsevier Ltd. All rights reserved.

Paludiculture on marginal lands - sustainable use of wet peatlands

NASA Astrophysics Data System (ADS)

Oehmke, Claudia; Dahms, Tobias; Wichmann, Sabine; Wichtmann, Wendelin

2017-04-01

Peatlands are marginal lands. If they are drained, they show a short initial productive period. Soil degradation due to peat oxidation leads to numerous problems which increasingly restrict agricultural use and cause significant environmental impacts such as greenhouse gas emissions and eutrophication and thereby produce high external costs. Worldwide greenhouse gas emissions from drained peatlands have a significant share ( 10%) in the emissions from agriculture, forestry and other land use (AFOLU) sectors (Smith et al. 2014). In Germany they contribute more than 35% to the total emissions from agriculture (agricultural sector and cropland and grassland management) (UBA 2016). Rewetting drained peatlands can significantly reduce environmental problems caused by peatland drainage. Continuation of agricultural use with adapted crops and machinery, so called paludiculture (Latin ‚palus' = swamp) stops further degradation, maintains the peat body, reduces climate change mitigation and produces renewable fuels and raw materials. Fen and bog soils are suitable for various different paludicultures. The biomass of Sphagnum (sphagnum farming) cultivated on cut-over bogs or degraded bog grasslands can be used as raw material for horticultural growing media. Flood-tolerant and productive plant species like Common Reed, Reed Canary Grass, Cattail, Black Alder and different Sedge species are suitable for paludiculture on fen soils. Biomass utilization ranges from traditional forms, like fodder production or the use of Common Reed as roof thatch, to new utilization options, that includes biomass use for heat generation, co-subtrates for biorefineries or construction and insulation products. The above-ground biomass of one hectare Common Reed (winter yield=8 t DM) equates to an energy content of 3,000 litre heating oil. A district heating plant (800 kW) in NE Germany demonstrates the feasibility of using biomass from wet fen meadows for local heat generation. Moreover, tests of biomass pellets from paludiculture showed promising results for small (<100KW) and medium scale boilers (<500kW). More examples for paludiculture production and utilization, harvest and logistics, ecosystem services, and economics are described in Wichtmann et al. 2016. Paludiculture is the only sustainable land use concept for marginal peatlands. The implementation of paludiculture on degraded organic soils after rewetting and its biomass use offers renewable biomass sources that have great potential for contributing to the local supply and therewith to the regional added values while preserving organic soils and reducing greenhouse gas emissions. Umweltbundesamt (UBA) (2016) National Inventory Report for the German, Greenhouse Gas Inventory 1990 - 2014, Dessau-Roßlau, 1035 p. Smith, P.; Bustamante ,M.; Ahammad H. et al. (2014) Agriculture, Forestry and Other Land Use (AFOLU). In: Climate Change 2014, Mitigation. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, pp. 799 - 890, Cambridge University Press Cambridge Wichtmann, W.; Joosten, H.; Schröder, C. (2016): Paludiculture, productive use of wet peatlands. Climate protection, biodiversity, regional economic benefits. Schweizerbart Science Publishers, Stuttgart, 272 p.

Sediment geochemistry as potential sea-level indicators to assess coseismic vertical displacements above the Alaska-Aleutian megathrust

NASA Astrophysics Data System (ADS)

Bender, A. M.; Witter, R. C.; Munk, L. A.

2012-12-01

Nearly the entire 4000-km-long Alaska-Aleutian megathrust has ruptured in large or great (Mw ≥8) earthquakes in the past 100 years, yet paleoseismic records of earlier events are only documented east of Kodiak Is. in the region of the 1964 Alaska earthquake. The Mw 9.2 1964 earthquake dropped the coast along Cook Inlet and Turnagain Arm by ≤1.8 m and raised shore platforms around Prince William Sound by ≤3 m. Evidence of sudden (coseismic) vertical displacements during megathrust earthquakes are archived in coastal sediments as sharp stratigraphic contacts that record rapid relative sea-level (RSL) changes. We use geochemical analyses of coastal sediments to detect sudden RSL changes at 2 sites above the Alaska-Aleutian megathrust. One site on Knik Arm near Anchorage subsided ~0.6 m during the 1964 earthquake. The other site overlies the Shumagin Islands segment of the megathrust, without rupture since before 1903. Relative to terrestrial sources of sediment, marine sources should be enriched in δ13C, δ15N, and have higher C:N, and Cl- concentrations. Our analyses will test whether these geochemical proxies can provide evidence for sudden RSL change across stratigraphic contacts that record coseismic uplift or subsidence. Coseismic subsidence should be represented by contacts that place sediment with enriched δ13C, δ15N signatures, elevated C:N and Cl- concentrations over sediment with lower values of these geochemical proxies and the reverse for coseismic uplift. A 1-2 m tall, ~0.5-km-long bluff along Knik Arm exposes three buried wetland soils overlain by gray mud. The soils become faint and pinch out to the northeast near a large tidal channel. Other studies of similar buried soils at adjacent sites suggest the youngest soil at Knik Arm subsided in 1964. 14C analyses of plant fossils in two older soils will provide age estimates for earlier events. We will apply the proposed geochemical methods to 20 samples collected along a forested upland to tidal mud flat transect to distinguish terrestrial from marine sediment. On Simeonof Is., stratigraphy beneath a peat bog adjacent to a tidal lagoon consists of basal marine sand overlain by ~0.6-1.5 m of peat. The presence of Arachnoidiscus japonicas, benthic marine diatom, implies a marine sand source. Sphagnum spp. and absence of marine foraminifera indicate freshwater peat. We analyzed δ13C, δ15N, and C:N from bulk sediment, and Cl- from water soluble fraction of sediment in a 1.3-m bog core. Freshwater peat at depths of 0.0-26.0, and 33.0-78.5 cm have δ13C ranging from -25.02 to -27.35 ‰, δ15N from 3.30-9.93‰, C:N of 10.16-17.89, and Cl- concentrations of 0.9-25.9 mg/L. Sand dominated intervals at 26.0-33.0, and 78.5-130 cm have δ13C ranging from -17.24 to -26.50‰, δ15N from 8.30-11.11‰ , C:N of 0.30-29.6 and Cl- concentrations of 0.7-19.3 mg/L. The data also indicate that average δ13C and δ15N values are enriched in marine sand relative to freshwater peat, respectively by 3.27‰ and 3.10‰. Also C:N ratios and Cl- concentrations are lower in marine sand, respectively by 23.1 and 0.1 mg/L. Hence, δ13C and δ15N show promise as geochemical proxies to distinguish terrestrial from marine sediment for future Alaska-Aleutian paleoseismic studies west of Kodiak Is.

The response of soil carbon storage and microbially mediated carbon turnover to simulated climatic disturbance in a northern peatland forest. Revisiting the concept of soil organic matter recalcitrance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kostka, Joel

The goal of this project was to investigate changes in the structure of dissolved and solid phase organic matter, the production of CO 2 and CH 4, and the composition of decomposer microbial communities in response to the climatic forcing of environmental processes that determine the balance between carbon gas production versus storage and sequestration in peatlands. Cutting-edge analytical chemistry and next generation sequencing of microbial genes were been applied to habitats at the Marcell Experimental Forest (MEF), where the US DOE’s Oak Ridge National Laboratory and the USDA Forest Service are constructing a large-scale ecosystem study entitled, “Spruce andmore » Peatland Responses Under Climatic and Environmental Change”(SPRUCE). Our study represented a comprehensive characterization of the sources, transformation, and decomposition of organic matter in the S1 bog at MEF. Multiple lines of evidence point to distinct, vertical zones of organic matter transformation: 1) the acrotelm consisting of living mosses, root material, and newly formed litter (0-30 cm), 2) the mesotelm, a mid-depth transition zone (30-75 cm) characterized by labile organic C compounds and intense decomposition, and 3) the underlying catotelm (below 75cm) characterized by refractory organic compounds as well as relatively low decomposition rates. These zones are in part defined by physical changes in hydraulic conductivity and water table depth. O-alkyl-C, which represents the carbohydrate fraction in the peat, was shown to be an excellent proxy for soil decomposition rates. The carbon cycle in deep peat was shown to be fueled by modern carbon sources further indicating that hydrology and surface vegetation play a role in belowground carbon cycling. We provide the first metagenomic study of an ombrotrophic peat bog, with novel insights into microbial specialization and functions in this unique terrestrial ecosystem. Vertical structuring of microbial communities closely paralleled the chemical evolution of peat, with large shifts in microbial populations occurring in the biogeochemical hotspot, the mesotelm, where the highest rates of decomposition were detected. Stable isotope geochemistry and potential rates of methane production paralleled vertical changes in methanogen community composition to indicate a predominance of acetoclastic methanogenesis mediated by the Methanosarcinales in the mesotelm, while hydrogen-utilizing methanogens dominated in the deeper catotelm. Evidence pointed to the availability of phosphorus as well as nitrogen limiting the microbially-mediated turnover of organic carbon at MEF. Prior to initiation of the experimental treatments, our study provided key baseline data for the SPRUCE site on the vertical stratification of peat decomposition, key enzymatic pathways, and microbial taxa containing these pathways. The sensitivity of soil carbon turnover to climate change is strongly linked to recalcitrant carbon stocks and the temperature sensitivity of decomposition is thought to increase with increasing molecular complexity of carbon substrates. This project delivered results on how climate change perturbations impact the microbially-mediated turnover of recalcitrant organic matter in peatland forest soils, both under controlled conditions in the laboratory and at the ecosystem-scale in the field. This project revisited the concept of “recalcitrance” in the regulation of soil carbon turnover using a combination of natural abundance radiocarbon and optical spectroscopic measurements on bulk DOM, and high resolution molecular characterization of DOM. The project elucidated how organic matter reactivity and decomposition will respond to climate change in a both a qualitative (organic matter lability) and quantitiative (increased rates) manner. An Aromaticity Index was developed to represent a more direct and accurate parameter for modeling of DOM reactivity in peatlands. The abundance and community composition of soil microorganisms that mediate C cycling were interrogated with depth in the peat, with season, and in manipulated climate enclosures at unprecedented resolution. Therefore this project delivered strategic new insights on the functioning of peatland ecosystems that collectively store approximately one-third of the world's soil carbon. Furthermore, results from the detailed characterization of DOM lability and microbial community structure/ function will be employed to further develop biogeochemical models to include microbial respiration pathways as well as to track carbon flow with a term that incorporates relative reactivity based on aromaticity index. As it stands now, detailed soil organic matter structure and microbial parameters are not included in Earth system models.« less

Nongrowing season methane emissions-a significant component of annual emissions across northern ecosystems.

PubMed

Treat, Claire C; Bloom, A Anthony; Marushchak, Maija E

2018-03-22

Wetlands are the single largest natural source of atmospheric methane (CH 4 ), a greenhouse gas, and occur extensively in the northern hemisphere. Large discrepancies remain between "bottom-up" and "top-down" estimates of northern CH 4 emissions. To explore whether these discrepancies are due to poor representation of nongrowing season CH 4 emissions, we synthesized nongrowing season and annual CH 4 flux measurements from temperate, boreal, and tundra wetlands and uplands. Median nongrowing season wetland emissions ranged from 0.9 g/m 2 in bogs to 5.2 g/m 2 in marshes and were dependent on moisture, vegetation, and permafrost. Annual wetland emissions ranged from 0.9 g m -2  year -1 in tundra bogs to 78 g m -2  year -1 in temperate marshes. Uplands varied from CH 4 sinks to CH 4 sources with a median annual flux of 0.0 ± 0.2 g m -2  year -1 . The measured fraction of annual CH 4 emissions during the nongrowing season (observed: 13% to 47%) was significantly larger than that was predicted by two process-based model ensembles, especially between 40° and 60°N (modeled: 4% to 17%). Constraining the model ensembles with the measured nongrowing fraction increased total nongrowing season and annual CH 4 emissions. Using this constraint, the modeled nongrowing season wetland CH 4 flux from >40° north was 6.1 ± 1.5 Tg/year, three times greater than the nongrowing season emissions of the unconstrained model ensemble. The annual wetland CH 4 flux was 37 ± 7 Tg/year from the data-constrained model ensemble, 25% larger than the unconstrained ensemble. Considering nongrowing season processes is critical for accurately estimating CH 4 emissions from high-latitude ecosystems, and necessary for constraining the role of wetland emissions in a warming climate. © 2018 John Wiley & Sons Ltd.

From Leaf Synthesis to Senescence: n-Alkyl Lipid Abundance and D/H Composition Among Plant Species in a Temperate Deciduous Forest at Brown's Lake Bog, Ohio, USA

NASA Astrophysics Data System (ADS)

Freimuth, E. J.; Diefendorf, A. F.; Lowell, T. V.

2014-12-01

The hydrogen isotope composition (D/H, δD) of terrestrial plant leaf waxes is a promising paleohydrology proxy because meteoric water (e.g., precipitation) is the primary hydrogen source for wax synthesis. However, secondary environmental and biological factors modify the net apparent fractionation between precipitation δD and leaf wax δD, limiting quantitative reconstruction of paleohydrology. These secondary factors include soil evaporation, leaf transpiration, biosynthetic fractionation, and the seasonal timing of lipid synthesis. Here, we investigate the influence of each of these factors on n-alkyl lipid δD in five dominant deciduous angiosperm tree species as well as shrubs, ferns and grasses in the watershed surrounding Brown's Lake Bog, Ohio, USA. We quantified n-alkane and n-alkanoic acid concentrations and δD in replicate individuals of each species at weekly to monthly intervals from March to October 2014 to assess inter- and intraspecific isotope variability throughout the growing season. We present soil, xylem and leaf water δD from each individual, and precipitation and atmospheric water vapor δD throughout the season to directly examine the relationship between source water and lipid isotope composition. These data allow us to assess the relative influence of soil evaporation and leaf transpiration among plant types, within species, and along a soil moisture gradient throughout the catchment. We use leaf water δD to approximate biosynthetic fractionation for each individual and test whether this is a species-specific and seasonal constant, and to evaluate variation among plant types with identical growth conditions. Our high frequency sampling approach provides new insights into the seasonal timing of n-alkane and n-alkanoic acid synthesis and subsequent fluctuations in concentration and δD in a temperate deciduous forest. These results will advance understanding of the magnitude and timing of secondary influences on the modern leaf wax δD signal, thereby improving paleohydrology information extracted from leaf wax δD.

Accumulation rates and predominant atmospheric sources of natural and anthropogenic Hg and Pb on the Faroe Islands

NASA Astrophysics Data System (ADS)

Shotyk, W.; Goodsite, M. E.; Roos-Barraclough, F.; Givelet, N.; Le Roux, G.; Weiss, D.; Cheburkin, A. K.; Knudsen, K.; Heinemeier, J.; van Der Knaap, W. O.; Norton, S. A.; Lohse, C.

2005-01-01

A monolith representing 5420 14C yr of peat accumulation was collected from a blanket bog at Myrarnar, Faroe Islands. The maximum Hg concentration (498 ng/g at a depth of 4.5 cm) coincides with the maximum concentration of anthropogenic Pb (111 μg/g). Age dating of recent peat accumulation using 210Pb (CRS model) shows that the maxima in Hg and Pb concentrations occur at AD 1954 ± 2. These results, combined with the isotopic composition of Pb in that sample ( 206Pb/ 207Pb = 1.1720 ± 0.0017), suggest that coal burning was the dominant source of both elements. From the onset of peat accumulation (ca. 4286 BC) until AD 1385, the ratios Hg/Br and Hg/Se were constant (2.2 ± 0.5 × 10 -4 and 8.5 ± 1.8 × 10 -3, respectively). Since then, Hg/Br and Hg/Se values have increased, also reaching their maxima in AD 1954. The age date of the maximum concentrations of anthropogenic Hg and Pb in the Faroe Islands is consistent with a previous study of peat cores from Greenland and Denmark (dated using the atmospheric bomb pulse curve of 14C), which showed maximum concentrations in AD 1953. The average rate of atmospheric Hg accumulation from 1520 BC to AD 1385 was 1.27 ± 0.38 μg/m 2/yr. The Br and Se concentrations and the background Hg/Br and Hg/Se ratios were used to calculate the average rate of natural Hg accumulation for the same period, 1.32 ± 0.36 μg/m 2/yr and 1.34 ± 0.29 μg/m 2/yr, respectively. These fluxes are similar to the preanthropogenic rates obtained using peat cores from Switzerland, southern Greenland, southern Ontario, Canada, and the northeastern United States. Episodic volcanic emissions and the continual supply of marine aerosols to the Faroe Islands, therefore, have not contributed significantly to the Hg inventory or the Hg accumulation rates, relative to these other areas. The maximum rate of Hg accumulation was 34 μg/m 2/yr. The greatest fluxes of anthropogenic Hg accumulation calculated using Br and Se, respectively, were 26 and 31 μg/m 2/yr. The rate of atmospheric Hg accumulation in 1998 (16 μg/m 2/yr) is comparable to the values recently obtained by atmospheric transport modeling for Denmark, the Faroe Islands, and Greenland.

Regional Haze Evolved from Peat Fires - an Overview

NASA Astrophysics Data System (ADS)

Hu, Yuqi; Rein, Guillermo

2016-04-01

This work provides an overview of haze episodes, their cause, emissions and health effects found in the scientific literature. Peatlands, the terrestrial ecosystems resulting from the accumulation of partially decayed vegetation, become susceptible to smouldering fires because of natural droughts or anthropogenic-induced drainages. Once ignited, smouldering peat fires persistently consume large amounts of soil carbon in a flameless form. It is estimated that the average annual carbon gas emissions (mainly CO2 and CO) from peat fires are equivalent to 15% of manmade emissions, representing influential perturbation of global carbon circle. In addition to carbon emissions, smouldering peat fires emit substantial quantities of heterogeneous smoke, which is responsible for haze phenomena, has not yet been fully studied. Peat-fire-derived smoke is characterized by high concentration of particulate matter (PM), ranging from nano-scale ultrafine fraction (PM1, particle diameter < 1 μm) to micro-scale fine (PM2.5, particle diameter < 2.5 μm) and coarse fraction (PM10, particle diameter < 10 μm). The dispersal of the smoke could be blocked due to the stagnant weather condition, and then low buoyant smoke plume could accumulate and migrate long distances, leading to regional haze. Apart from air quality deterioration, haze leads to severe reduction in visibility, which strongly affects local transportation, construction, tourism and agriculture-based industries. For example, an unprecedented peatland mega-fire burst on the Indonesian islands Kalimantan and Sumatra during the 1997 El-Niño event, resulting in transboundary smoke-haze disaster. Severe haze events continue to appear in Southeast Asia every few years due to periodical peat fires in this region. In addition, smouldering peat fires have been frequently reported in tropical, temperate and boreal regions (Botswana in 2000, North America in 2004, Scotland in 2006 and Central Russia in 2010 et al.), peat-fire-induced haze has become a regional seasonal phenomenon. Exposure to smoky haze results in deleterious physiologic responses, predominantly to the respiratory and cardiovascular systems. In 1997, an estimation of 100 million people in 5 countries in Southeast Asia were affected by Indonesia haze episode while 20 million people suffered from respiratory problems in Indonesia alone. Fine PM fraction generated from peat fires could penetrate into lower respiratory tracks and exacerbate respiratory diseases including chronic bronchitis, emphysema and asthma. Epidemiological studies show that direct exposure to haze pollution is associated with decreased pulmonary function and increased morbidity and mortality among individuals with pre-existent cardiovascular diseases. Reported cases of acute respiratory infection increased 3.8 times during the 1997 Indonesia haze episode (1,446,120 cases in total with 527 haze-related deaths). Collectively, peat fire and the resultant haze considerably affect the local society in many aspects, and more thorough research need to be carried out for further haze mitigation and governance. Corresponding author: Dr. Guillermo Rein: g.rein@imperial.ac.uk

Restoration of pitcher plant bogs in eastern Texas, USA

Treesearch

Ronald Mize; Robert E. Evans; Barbara R. MacRoberts; Michael H. MacRoberts; D. Craig Rudolph

2005-01-01

Pitcher plant bogs, also referred to as hillside seepages bogs or hillside bogs, are extremely restricted on the West Gulf Coastal Plain. the number and extent of extant bogs is in the low hundreds, comprising no more than a few thousand hectares of habitat. These bogs support a large number of plant species of significant conservation concern. threats to existing bogs...

Singulisphaera rosea sp. nov., a planctomycete from acidic Sphagnum peat, and emended description of the genus Singulisphaera.

PubMed

Kulichevskaya, Irina S; Detkova, Ekaterina N; Bodelier, Paul L E; Rijpstra, W Irene C; Damsté, Jaap S Sinninghe; Dedysh, Svetlana N

2012-01-01

An aerobic, pink-pigmented, budding bacterium, designated strain S26(T), was isolated from an acidic Sphagnum peat bog of north-western Russia. Cells were non-motile and spherical, occurring singly, in pairs or in short chains, and were able to attach to surfaces by means of a holdfast material. Strain S26(T) was a moderately acidophilic, mesophilic organism capable of growth at pH 3.2-7.1 (optimum at pH 4.8-5.0) and at 4-33 °C (optimum at 20-26 °C). Most sugars, several organic acids and polyalcohols were the preferred growth substrates. The major fatty acids were C(16:0), C(18:1)ω9c and C(18:2)ω6c,12c. The major neutral lipids were n-C(31:9) hydrocarbon and squalene; the polar lipids were phosphatidylglycerol, phosphatidylcholine and components with an unknown structure. The DNA G+C content of strain S26(T) was 62.2 mol%. 16S rRNA gene sequence analysis showed that strain S26(T) is a member of the order Planctomycetales. Among taxonomically characterized representatives of this order, highest levels of 16S rRNA gene sequence similarity (95.1-95.2%) were observed with strains of the non-filamentous, peat-inhabiting planctomycete Singulisphaera acidiphila. Strain S26(T) could be differentiated from Singulisphaera acidiphila based on pigmentation, significant differences in substrate utilization patterns, greater tolerance of acidic conditions and the presence of C(16:1)ω9c. Based on the data presented, strain S26(T) is considered to represent a novel species of the genus Singulisphaera, for which the name Singulisphaera rosea sp. nov. is proposed; the type strain is S26(T) (=DSM 23044(T)=VKM B-2599(T)).

Microbiological profile of selected mucks

NASA Astrophysics Data System (ADS)

Dąbek-Szreniawska, M.; Wyczółkowski, A. I.

2009-04-01

INTRODUCTION Matyka-Sarzynska and Sokolowska (2000) emphasize that peats and peat soils comprise large areas of Poland. The creation of soil begins when the formation of swamp has ended. Gawlik (2000) states that the degree of influence of the mucky process of organic soils on the differentiations of the conditions of growth and development of plants is mainly connected with the changes of moisture-retentive properties of mucks which constitute the material for these soils, and the loss of their wetting capacities. The above-mentioned changes, which usually occur gradually and show a clear connection with the extent of dehydration and, at times, with its duration, intensify significantly when the soils are under cultivation. The mucky process of peat soils leads to transformations of their physical, chemical and biological properties. The main ingredient of peat soils is organic substance. The substance is maintained inside them by the protective activity of water. The process of land improvement reduces the humidity of the environment, and that Intensifies the pace of the activity of soil microorganisms which cause the decay of organic substance. The decay takes place in the direction of two parallel processes: mineralization and humification. All groups of chemical substances constituting peat undergo mineralization. Special attention should be called to the mineralization of carbon and nitrogen compounds, which constitute a large percentage of theorganic substance of the peat organic mass. Okruszko (1976) has examined scientificbases of the classification of peat soils depending on the intensity of the muck process. The aim of this publication was to conduct a microbiological characteristic of selected mucky material. METHODS AND MATERIALS Soil samples used in the experiments were acquired from the Leczynsko-Wlodawski Lake Region, a large area of which constitutes a part of the Poleski National Park, which is covered to a large extent with high peat bogs. It was a mucky-peat soil with different degrees of muck process, described by Gawlik (2000) as MtI - first step of muck process, and MtII - second step of muck process. The numbers of selected groups of microorganisms were established using the cultivation method. The total number of microorganisms, zymogenic, aerobic and anaerobic microorganisms (Fred, Waksman 1928), oligotrophic microorganisms, the number of fungi (Parkinson 1982), ammonifiers (Parkinson et al 1971), nitrogen reducers and amolytic microorganisms (Pochon and Tardieux 1962), were determined. RESULTS The interpretation of the obtained results should take into consideration not only the characteristics of the studied objects, but also the characteristics of the methods used and of the examined microorganisms. As a result of the experiments that were carried out, significant differences of the numbers of the examined groups of microorganisms, depending on the degree of the muck process, have been observed. The number of the examined groups was significantly higher in the soil at the first step muck process than the second step of muck process. Amylolytic bacteria were an exception. Probably, during the muck process, ammonification, nitrification and nitrogen reduction process take place at the same time, which is indicated by the number of individual groups of examined microorganisms. CONCLUSIONS During the muck process, the number of microorganisms in the soil decreases. It can be presupposed that during the muck process, the basic process realized by microorganisms is the degradation of organic substance, using nitrates as oxidizers. Dąbek-Szreniawska M.: 1992 Results of microbiological analysis related to soil physical properties. Zesz. Probl. Post. Nauk Roln., 398, 1-6. Fred E.B., Waksman S.A.: 1928 Laboratory manual of general microbiology. Mc Graw-Hill Book Company, New York - London pp. 145. Gawlik J.: 2000 Division of differently silted peat formations into classes according to their state of secondary transformations. Acta Agrophysica, 26, 17-24. Maciak F.: 1985 MateriaŁ y do ćwiczeń z rekultywacji teren

Paleoenvironmental and paleoclimatic investigations on Isla de los Estados, Argentina

NASA Astrophysics Data System (ADS)

Björck, S.; Fernandez, M.; Hjort, C.; Ljung, K.; Martinez, O.; Möller, P.; Ponce, F.; Rabassa, J.; Roig, F.; Unkel, I.; Wohlfarth, B.

2007-05-01

The expedition in November-December 2005 to Isla de los Estados (Staten Island) off the southeastern tip of South America was a cooperative venture between Lund University (LU) and Stockholm University (SU) in Sweden and the CADIC-CONICET Institute in Ushuaia, Argentina. The aim of the expedition was threefold: (1) to extend the Swedish paleoclimatic "ATLANTIS"-project (Greenland, Iceland, Faroe Islands, Azores, Grenada, Tristan da Cunha; PI S Björck) to the southern part of the South American continent, (2) to connect earlier glacial and climate history reconstructions from the Antarctic Peninsula to equivalents north of the Drake Passage in southernmost South America, and (3) to complement paleo-information available from the Tierra del Fuego mainland with information from Isla de los Estados. Focus was on two areas in the northern and north-western part of the island, Bahía Colnett and Bahia Crossley. Detailed geomorphologic and stratigraphic mapping of glacial deposits were combined with sampling sediments for OSL dating. To reconstruct the paleoclimatic development of Isla de los Estados since the last ice retreat, four main peat bog/lake sites were cored and sampled. In addition, living trees of Nothofagus and old logs preserved in the peat were sampled for dendrochronological and dendroclimatological studies. Preliminary results show that the deglaciation of the study area occurred before 16500 cal yr BP. Detailed multi- proxy analyses of the four sequences are under way and first results will be presented.

Interactive effects of wildfire and permafrost thaw on peatland carbon cycling

NASA Astrophysics Data System (ADS)

Olefeldt, David; Heffernan, William; Gibson, Carolyn; Burd, Katheryn; Estop-Aragones, Cristian

2017-04-01

Boreal peatland complexes in western Canada are fine-scale mosaics of permafrost affected peat plateaus interspersed with Sphagnum dominated thermokarst bogs where permafrost is absent. Wildfire further affects landscape patterning of peatland complexes, where virtually all peat plateaus are in a stage of secondary succession following wildfire. With climate change we expect both permafrost thaw and wildfire activity to increase in these landscapes, and to have important impacts on carbon cycling. In a number of studies, we have used soil chamber techniques to assess the influence of both permafrost thaw and wildfire on soil respiration, net ecosystem exchange and methane emissions. We used chronosequences to assess the influence of time since both permafrost thaw (3 - 15 years) and wildfire (20 - 150 years). Radiocarbon signatures of soil respiration in both burned and thawed locations was used to determine the contribution of aged soil carbon to soil respiration. We furthermore characterized individual and interactive effects of fire and thaw on microbial and photochemical lability of dissolved organic matter. At many field sites it was clear that recent wildfire had accelerated permafrost thaw, and we combined field observations of soil thermal regimes with remote sensing approaches to assess the role of wildfire for accelerating permafrost thaw over the last 50 years at a regional scale. Overall, our results highlight the need to consider both individual and interacting effects of thaw and fire for projections of the future carbon cycling at the regional level.

Impacts of peatland restoration on dissolved carbon loss from eroded upland peatlands in the UK

NASA Astrophysics Data System (ADS)

Evans, M.; Stimson, A.; Allott, T. E. H. A.; Holland, N.

2012-04-01

Upland blanket peatlands in the UK are severely degraded by extensive gully erosion. Large areas have experienced complete vegetation loss. In the last decade landscape scale approaches to the restoration of eroded and bare peat have been developed in the Peak District National Park in northern England. Bare peat is re-vegetated with a nurse crop of grasses established by the aerial application of lime, seed, and fertiliser. The approach has successfully re-vegetated large areas of eroded bog a nd has been shown to dramatically reduce particulate carbon losses in runoff. The impacts of the treatment on water quality and dissolved carbon loss have not previously been fully assessed. This paper reports results from a small catchment study assessing the impacts of restoration practice in the Peak District. Data from five small catchments are presented one re-vegetated, one intact and three eroded/bare catchments. Bi-weekly water samples have been taken from the catchments between January 2011 and February 2012 and during July 2012 two of the bare sites were treated with lime, seed, and fertiliser. The data show that there are significant spikes in nutrient flux post treatment and marked effects on dissolved carbon which include initial spikes in in DOC concentration but longer term reductions in DOC concentration. Monitoring is ongoing at these sites but the evidence to date points to at least a short term benefit in DOC flux reduction from this form of peatland restoration.

Holocene Paleohydrological Changes in Northern Michigan: Interpretations of Biomarker Distributions and Compound Specific Stable Isotope Analysis from Peatlands

NASA Astrophysics Data System (ADS)

Nichols, J. E.; Booth, R. K.; Jackson, S. T.; Pendall, E. G.; Huang, Y.

2006-12-01

Sediments of ombrotrophic peatlands are excellent archives for reconstructing past changes in precipitation/evaporation (P/E) balance. Multiproxy analysis of these sediments is critical for better understanding of climatic events experienced by these highly sensitive systems, as each proxy may respond to different climate parameters. In this study, we use distributions of n-alkanes and δD of Sphagnum biomarkers to interpret paleohydrology from sediments of Irwin Smith Bog, northern Michigan. We then integrate these data with pollen data and testate amoebae-inferred water table depth. Sphagnum moss is the dominant peat former in ombrotrophic bogs, but vascular plants become abundant when water tables are drawn down. Thus, the abundance of Sphagnum relative to vascular plants is indicative of peatland hydrology. The n-alkanes produced by Sphagnum differ from vascular plants in the relative abundance of the different homologues, with the former having excess amounts of shorter chain C23 n-alkane. We use several measures (compound ratios, PCA) to show changes in then-alkane distributions in the sediments, and thus changes in the peatland plant community. Our data provide high- resolution, quantitative paleohydrological records for the study region that are consistent with other records. We also show that the relative abundance of a newly identified Sphagnum biomarker, 2-heptacosanone, can be used to reconstruct changing plant communities. Because ombrotrophic systems lose water by evaporation, drier/warmer conditions cause hydrogen isotopic enrichment of bog water and Sphagnum biomarkers. We measured the δD of C23 n-alkane and 2-heptacosanone to provide additional paleoclimate information. Our multiproxy approach allows us to better understand the climate changes during key intervals of the Holocene. For example, a sharp decrease in the abundance of Tsuga canadensis (hemlock) pollen has been previously identified in records from many places throughout eastern North America. The cause of this mid-Holocene hemlock decline has been debated, making this interval of particular interest for paleoclimate studies. We will present new molecular and isotopic data to better understand the causation of this abrupt vegetation change.

Scots pine (Pinus sylvestris L.) based reconstruction of 130 years of water table fluctuations in a peatland and its relevance for moisture variability assessments

NASA Astrophysics Data System (ADS)

Tamkevičiūtė, Marija; Edvardsson, Johannes; Pukienė, Rūtilė; Taminskas, Julius; Stoffel, Markus; Corona, Christophe; Kibirkštis, Gintautas

2018-03-01

Continuous water-table (WT) measurements from peatlands are scarce and - if existing at all -very short. Consequently, proxy indicators are critically needed to simulate hydrological changes in peatlands over longer time periods. In this study, we demonstrate that tree-ring width (TRW) records of Scots pine (Pinus sylvestris L.) growing in the Čepkeliai peatland (southern Lithuania) can be used as a proxy to reconstruct hydrological variability in a raised bog environment. A two-step modelling procedure was applied to extend existing measurements and to develop a new and longer peatland WT time series. To this end, we used instrumental WT measurements extending back to 2002, meteorological records, a P-PET (difference between precipitation and potential evapotranspiration) series covering the period 1935-2014, so as to construct a tree-ring based time series of WT fluctuations at the site for the period 1870-2014. Strongest correlations were obtained between average annual WT measured at the bog margin and total P-PET over 7 years (r = 0.923, p < 0.00001), as well as between modelled WT and standardized TRW data with a two years lag (r = -0.602, p < 0.001) for those periods where WT fluctuated at the level of pine roots which is typically at <50 cm depth below the peat surface. Our results suggest that moisture is a limiting factor for tree growth at peatlands, but below a certain WT level (<50 cm under the soil surface), drought becomes a limiting factor instead. To validate the WT reconstruction from the Čepkeliai bog, results were compared to Nemunas river runoff since CE 1812 (r = 0.39, p < 0.00001, 1870-2014). We conclude that peatlands can act both as sinks and sources of greenhouse gases in case that hydrological conditions change, but that hydrological lags and complex feedbacks still hamper our understanding of several processes affecting the hydrology and carbon budget in peatlands. We therefore call for the development of further proxy records of water-table variability in peatlands to improve our understanding of peatland responses to climatic changes.

The Sphagnum microbiome supports bog ecosystem functioning under extreme conditions.

PubMed

Bragina, Anastasia; Oberauner-Wappis, Lisa; Zachow, Christin; Halwachs, Bettina; Thallinger, Gerhard G; Müller, Henry; Berg, Gabriele

2014-09-01

Sphagnum-dominated bogs represent a unique yet widely distributed type of terrestrial ecosystem and strongly contribute to global biosphere functioning. Sphagnum is colonized by highly diverse microbial communities, but less is known about their function. We identified a high functional diversity within the Sphagnum microbiome applying an Illumina-based metagenomic approach followed by de novo assembly and MG-RAST annotation. An interenvironmental comparison revealed that the Sphagnum microbiome harbours specific genetic features that distinguish it significantly from microbiomes of higher plants and peat soils. The differential traits especially support ecosystem functioning by a symbiotic lifestyle under poikilohydric and ombrotrophic conditions. To realise a plasticity-stability balance, we found abundant subsystems responsible to cope with oxidative and drought stresses, to exchange (mobile) genetic elements, and genes that encode for resistance to detrimental environmental factors, repair and self-controlling mechanisms. Multiple microbe-microbe and plant-microbe interactions were also found to play a crucial role as indicated by diverse genes necessary for biofilm formation, interaction via quorum sensing and nutrient exchange. A high proportion of genes involved in nitrogen cycle and recycling of organic material supported the role of bacteria for nutrient supply. 16S rDNA analysis indicated a higher structural diversity than that which had been previously detected using PCR-dependent techniques. Altogether, the diverse Sphagnum microbiome has the ability to support the life of the host plant and the entire ecosystem under changing environmental conditions. Beyond this, the moss microbiome presents a promising bio-resource for environmental biotechnology - with respect to novel enzymes or stress-protecting bacteria. © 2014 John Wiley & Sons Ltd.

Spatially explicit simulation of peatland hydrology and carbon dioxide exchange: Influence of mesoscale topography

NASA Astrophysics Data System (ADS)

Sonnentag, O.; Chen, J. M.; Roulet, N. T.; Ju, W.; Govind, A.

2008-06-01

Carbon dynamics in peatlands are controlled, in large part, by their wetness as defined by water table depth and volumetric liquid soil moisture content. A common type of peatland is raised bogs that typically have a multiple-layer canopy of vascular plants over a Sphagnum moss ground cover. Their convex form restricts water supply to precipitation and water is shed toward the margins, usually by lateral subsurface flow. The hydraulic gradient for lateral subsurface flow is governed by the peat surface topography at the mesoscale (˜200 m to 5 km). To investigate the influence of mesoscale topography on wetness, evapotranspiration (ET), and gross primary productivity (GPP) in a bog during the snow-free period, we compare the outputs of a further developed version of the daily Boreal Ecosystem Productivity Simulator (BEPS) with observations made at the Mer Bleue peatland, located near Ottawa, Canada. Explicitly considering mesoscale topography, simulated total ET and GPP correlate well with measured ET (r = 0.91) and derived gross ecosystem productivity (GEP; r = 0.92). Both measured ET and derived GEP are simulated similarly well when mesoscale topography is neglected, but daily simulated values are systematically underestimated by about 10% and 12% on average, respectively, due to greater wetness resulting from the lack of lateral subsurface flow. Owing to the differences in moss surface conductances of water vapor and carbon dioxide with increasing moss water content, the differences in the spatial patterns of simulated total ET and GPP are controlled by the mesotopographic position of the moss ground cover.

Effects of Spontaneous Colonization by Eriophorum vaginatum on Belowground C and N Mobilization and Greenhouse Gas Emissions in a Restored Boreal Peatland

NASA Astrophysics Data System (ADS)

Lazcano, C.; Brummell, M.; Strack, M.

2016-12-01

Peatland restoration aims at recovering the ecological function of these ecosystems as active C sinks by re-establishing Sphagnum-dominated vegetation. In addition, restoration encourages the establishment of naturally occurring vascular plant species from the local seed bank. Whereas these plants could contribute to a substantial short-term increase in C sequestration due to their large biomass accumulation, their impacts on peat biogeochemistry are complex and belowground C and N mobilization could be substantial, leading to increased greenhouse gas emissions. We investigated the effects of cottongrass (Eriophorum vaginatum), a common vascular plant species colonizing extracted peatlands, on porewater dissolved organic C (DOC) and total dissolved N (TDN) as well as CO2, CH4 and N2O fluxes in a cutover boreal bog in Alberta (Canada), restored three years prior to the study. We hypothesized that cottongrass would increase the concentration of DOC and TDN in porewater as well as net N2O and CH4 emission from peat compared to areas of bare peat or moss. We studied porewater chemistry and net gas exchange for CO2, CH4, and N2O, using static chambers, over one growing season (May-September 2015) and we compared between plots containing cottongrass and plots lacking vascular plants. Plots were located along a transect of increasing water table, to discriminate between the effects of cottongrass and the prevailing hydrological conditions on porewater chemistry and gas fluxes. Cottongrass presence had contrasting effects on porewater DOC chemistry depending on wetness of the site, reducing DOC concentration in dry sites but increasing it at wet sites as compared with bare plots. This suggests that DOC mobilization is primarily controlled by hydrological conditions rather than cottongrass presence. However, cottongrass significantly increased CH4 emissions independently of the plot moisture. Cottongrass presence reduced net emission of N2O in the later part of the growing season, with cottongrass plots frequently acting as net consumers in July and August. Porewater TDN was significantly higher under cottongrass at the wettest area of the site than under either bare or cottongrass plots at the drier area, suggesting nitrogen mobilization from peat by an interaction between cottongrass roots and water.

Carbon Sequestration and Peat Accretion Processes in Peatland Systems: A North-South Comparison

NASA Astrophysics Data System (ADS)

Richardson, C. J.; Wang, H.; Bridgham, S. D.

2012-12-01

Millions of hectares of peatlands exist in the U.S. and Canada but few comparisons have been made on the process controlling peat accretion, carbon sequestration and GHG losses across latitudinal gradients. Historic threats to carbon sequestration for these areas have been drainage and conversion to agriculture and forestry, which promotes the decomposition of the organic matter in the soil, leading to accelerated soil subsidence, severe carbon losses, and accelerated transport of C and nutrients to adjoining ecosystems. A more recent and insidious threat to the survival of peatlands worldwide is the increased temperature and drought conditions projected for many areas of global peatlands (IPCC 2007). A comparison of carbon sequestration rates and controlling processes for southeastern shrub bogs, the Florida Everglades and selected peatlands of the northern US and Canada under current climatic conditions reveals several major differences in controlling factors and rates of sequestration and carbon flux. Numerous studies have shown that drought or drainage can unlock historically stored carbon, thus releasing more CO2 ¬ and dissolved organic carbon (Blodau et al. 2004; Furukawa et al. 2005; Von Arnold et al. 2005; Hirano et al. 2007), and such effects might last for decades (Fenner & Freeman 2011). The main driver of this process is the O2 introduced by drought or drainage, which will increase the activity of phenol oxidase, then accelerate the decomposition of phenol compounds, which is generally considered the "enzymatic latch" for carbon storage in peatlands (Freeman et al. 2001). However, our recent studies in southeastern peatlands along the coast of North Carolina have found that drought or drainage does not affect CO2 emission in some southern peatlands where the initial water level is below the ground surface (unsaturated peats), as polyphenol increases rather than decreases. Our results suggest that additional controlling factors, rather than anoxia exist in unsaturated peats, allowing them to accumulate carbon, and resist decomposition and CO2 losses. The importance of native phenolic producing plant species and substrate quality are key controlling factors. Our study offers new evidence that frequently occurring summer drought or climate-induced moderate drought will not increase the loss of stored carbon in unsaturated peatlands. These findings have important ramifications concerning carbon storage and losses in peatlands under future climate change predictions.

A Mediterranean free-floating peat mire hosts microbial communities shared by cold latitude habitats

NASA Astrophysics Data System (ADS)

Concheri, Giuseppe; Stevanato, Piergiorgio; Zaccone, Claudio; Shotyk, William; D'Orazio, Valeria; Miano, Teodoro; Lobianco, Daniela; Piffanelli, Pietro; Rizzi, Valeria; Ferrandi, Chiara; Squartini, Andrea

2017-04-01

The microbiological features of a peculiar and hitherto unexplored environment, i.e., a 4m-deep, free-floating peat island located within the Posta Fibreno lake (central Italy), were analyzed via DNA-based techniques. Methods included RealTime PCR targeting for nitrogen (N) cycle genes (nitrification from eubacteria and archaea, denitrification, N fixation), and Next Generation Sequencing (NGS) using an Illumina platform of prokaryotic (16S) and eukaryotic (ITS) amplicons to assess community members identity and abundance. Two depths were sampled at ca. 40 and 280 cm from the surface, the former corresponding to a portion of Sphagnum residues accumulated less than 30 yrs ago above the water level, and the latter mainly consisting of silty peat belonging to the deeply submerged part of the island, dating back to 1520-1660 AD. Bacterial gene abundances for the N cycle were consistently higher in the deeper sample. Sequencing analyses allowed identifying for the surface sample 1738 prokaryotic and 310 eukaryotic Operational Taxonomic Units (OTUs), while, for the deeper sample, the corresponding values were 2026 and 291 respectively. There was a very limited taxa overlap between the two layers' communities in which dominant taxa featured two different sulphate-reducing Deltaproteobacteria for prokaryotes. For eukaryotes, the surface sample was dominated by the Neobulgaria (Ascomycota) genus, while in the deeper one three quarters of the ITS reads were featured by a taxon observed in Antarctic lakes. The functional guilds represented pertain mostly to species involved in slow organic matter degradation and contexts in which dissolved organic carbon contains one-atom compounds, supportive of methylotrophy and methanogenesis. The identity of taxa partitioning between the acidic surface layer and the neutral core is very reminiscent of the differences reported between bogs and fens peatland types respectively, supporting the view of Posta Fibreno as a hybrid between the two main models. A remarkable feature is the coincidence of most taxa observed with database subjects isolated from mires and lakes in boreal/polar environments in spite of the fact that Posta Fibreno is located in sub-Mediterranean climate conditions. This instance suggests a common ecological feature linking peat-forming mires and habitats alike, in which the process factor would rule in determining the biotic composition in spite of the macroclimatic and geographical variables. The principle offers interpretive clues for a deeper understanding of a number of other biotic-environmental interplay contexts.

Impact of long-term wetting on belowground respiration and methanogenesis in Luther Bog, Ontario

NASA Astrophysics Data System (ADS)

Goebel, Marie; Blodau, Christian

2016-04-01

Peatlands play a major role in the global carbon cycle. They store one-third of total world soil carbon, sequester carbon dioxide (CO2) and release CO2 and methane (CH4). Climate and land-use change are predicted to cause either wetter winters and wetter summers or wetter winters and drier summers in the area where northern peatlands are located. Feedback on processes in the peat is poorly understood on the time scale of decades. In this study, we investigated impacts of long-term wetting and long-term fluctuating water table on potential CO2 and CH4 production rates and organic matter quality of the fractions bulk peat, pore water and leachate. Bulk peat potential CO2 production rates of 2.38 to 25.55 μmol g-1 d-1 (aerobic) and 1.53 to 7.33 μmol g-1 d-1 (anaerobic) decreased with depth along with a decrease in organic matter quality. Potential CH4 production rates (0.002 to 2.60 μmol g-1 d-1) increased with anaerobic conditions and a lack of electron acceptors rather than being dependent on the availability of labile organic matter. This pattern was less evident in solute fraction samples where labile compounds in top layers were probably either too labile to be detected or water movement obscured differences between depths. Bulk peat potential anaerobic CO2 and CH4 production increased through long-term wetting. As wetting did not change organic matter quality or aerobic production rates, increased anaerobic production rates likely originate from microorganisms adapted to anaerobic conditions. All indicators of organic matter quality, FTIR ratios, SUVA254, E2:E3, HIX, FI and PARAFAC, provided similar results. Other than expected, wetting did not result in higher organic matter quality in bulk peat and leachate. Drier conditions in summer led to reduced organic matter quality. In pore water, long-term wetter conditions resulted in a higher organic matter quality. Slow-down of decomposition due to anaerobic conditions is unlikely, as this was not the case with respect to the other fractions. Mixing with groundwater could have transported organic matter of high quality to the wetted site. Potential CO2 production rates were not affected by long-term water table change. Organic matter quality of the wetted site may have been also overestimated in our study as vegetation change may have changed litter and peat quality as well. This study revealed that long-term wetting probably does not change organic matter quality as decisively as expected. Potential anaerobic CO2 and CH4 production rates rather increased as long as conditions were more constantly anoxic. Long-term lowered or fluctuating water table could potentially result in smaller future emissions due to a reduced organic matter quality, but also to less carbon sequestration.

Habitat heterogeneity and connectivity shape microbial communities in South American peatlands.

PubMed

Oloo, Felix; Valverde, Angel; Quiroga, María Victoria; Vikram, Surendra; Cowan, Don; Mataloni, Gabriela

2016-05-10

Bacteria play critical roles in peatland ecosystems. However, very little is known of how habitat heterogeneity affects the structure of the bacterial communities in these ecosystems. Here, we used amplicon sequencing of the 16S rRNA and nifH genes to investigate phylogenetic diversity and bacterial community composition in three different sub-Antarctic peat bog aquatic habitats: Sphagnum magellanicum interstitial water, and water from vegetated and non-vegetated pools. Total and putative nitrogen-fixing bacterial communities from Sphagnum interstitial water differed significantly from vegetated and non-vegetated pool communities (which were colonized by the same bacterial populations), probably as a result of differences in water chemistry and biotic interactions. Total bacterial communities from pools contained typically aquatic taxa, and were more dissimilar in composition and less species rich than those from Sphagnum interstitial waters (which were enriched in taxa typically from soils), probably reflecting the reduced connectivity between the former habitats. These results show that bacterial communities in peatland water habitats are highly diverse and structured by multiple concurrent factors.

Hydrologic data for the Great and Denbow heaths in eastern Maine, October 1980 through September 1981

USGS Publications Warehouse

Nichols, Wallace J.; Smath, J.A.; Adamik, J.T.

1983-01-01

Hydrologic data collected on the Great and Denbow Heaths, Maine, include precipitation, pan evaporation, air temperatures, streamflow, groundwater levels, and water quality constituents. These data were collected for a peat bog hydrology study conducted in cooperation with the Maine Geological Survey. The data network consisted of climate information from three rain gages, an evaporation pan, and two maximum-minimum thermometers; surface water information from two continuous gaging stations and 19 partial record sites; groundwater information from an observation well equipped with a continuous recorder and 106 piezometers; and water quality information from 13 wells and seven surface water sites. Water quality constituents include: field determinations of pH, specific conductance, and temperature, and laboratory determinations of common inorganic cations and anions, trace elements, and selected organic compounds. Methods used for the collection and analyses of data included standard Survey techniques modified for the unique hydrologic environment of the study area. (Author 's abstract)

High methane emissions dominate annual greenhouse gas balances 30 years after bog rewetting

NASA Astrophysics Data System (ADS)

Vanselow-Algan, M.; Schmidt, S. R.; Greven, M.; Fiencke, C.; Kutzbach, L.; Pfeiffer, E.-M.

2015-02-01

Natural peatlands are important carbon sinks and sources of methane (CH4). In contrast, drained peatlands turn from a carbon sink to a carbon source and potentially emit nitrous oxide (N2O). Rewetting of peatlands thus implies climate change mitigation. However, data about the time span that is needed for the re-establishment of the carbon sink function by restoration is scarce. We therefore investigated the annual greenhouse gas (GHG) balances of three differently vegetated bog sites 30 years after rewetting. All three vegetation communities turned out to be sources of carbon dioxide (CO2) ranging between 0.6 ± 1.43 t CO2 ha-2 yr-1 (Sphagnum-dominated vegetation) and 3.09 ± 3.86 t CO2 ha-2 yr-1 (vegetation dominated by heath). While accounting for the different global warming potential (GWP) of the three greenhouse gases, the annual GHG balance was calculated. Emissions ranged between 25 and 53 t CO2-eq ha-1 yr-1 and were dominated by large emissions of CH4 (22 up to 51 t CO2-eq ha-1 yr-1), while highest rates were found at purple moor grass (Molinia caerulea) stands. These are to our knowledge the highest CH4 emissions so far reported for bog ecosystems in temperate Europe. As the restored area was subject to large fluctuations in water table, we conclude that the high CH4 emission rates were caused by a combination of both the temporal inundation of the easily decomposable plant litter of this grass species and the plant-mediated transport through its tissues. In addition, as a result of the land use history, the mixed soil material can serve as an explanation. With regards to the long time span passed since rewetting, we note that the initial increase in CH4 emissions due to rewetting as described in the literature is not limited to a short-term period.

Geoecological controls on net mercury retention in northern peatlands

NASA Astrophysics Data System (ADS)

Bindler, R.; Rydberg, J.

2010-12-01

Peatlands, which receive much or all of their element inputs (e.g. nutrients or trace metals) via the atmosphere, are considered an ideal archive for studying past changes in mercury (Hg) deposition. These archives potentially contain information not only on important anthropogenic contributions to the environment over the past few centuries, but also on the natural antecedent conditions over the past several millennia. However, the assumption that Hg accumulation rates in peat represent an absolute record of past atmospheric deposition has proved problematic. In on-going studies of Hg retention in northern peatlands (bogs and oligotrophic fens) we find that net Hg accumulation is influenced by a range of geoecological factors in addition to actual changes in atmospheric deposition. Factors that influence the interception and net retention of Hg include differences in vegetation and microtopography - both of which may enhance dry deposition, and properties and processes within the peat such as decomposition that might influence long-term retention. Wetness, too, may play an important role in net retention in the surface peat through increased evasive losses of Hg. Differences between Hg concentrations in vascular plants and mosses are well established (at our site: 5-15 ng/g for leaves/needles of cottongrass, heather, Labrador tea and pine; 15-45 ng/g for mosses Sphagnum centrale and S. rubellum), but we also measured significant differences between different mosses within the same plots (S. rubellum, 24±3 ng/g; S. centrale, 18±2 ng/g). Further differences in Hg concentrations occur for single moss species in different settings; for example, Hg concentrations in S. centrale in open Sphagnum-only plots relative to plots including a mixture of vascular plants that form a field-layer canopy are 18±2 and 32±6 ng/g, respectively. As a result, sampling sites consisting of both Sphagnum and vascular plants have long-term cumulative inventories of mercury in the peat that are >60% greater than in areas characterized only by a mixture of Sphagnum species (where the water table is also relatively highest). However, comparisons of Pb-210 inventories, an independent proxy for atmospheric deposition, indicate that this increase in interception should be ≤40%. Based on data also from other sites, where Hg inventories may vary between cores by 2-4 times, we have observed that wetter sites invariably have the lowest cumulative Hg inventories and hypothesize greater evasive loss from wetter sites, which has been shown for soils. We will investigate this during fall 2010. Although we have identified a number of factors that complicate the use of peat records as absolute records of mercury deposition, these problems can be circumvented by multi-core studies that provide a more robust estimate of mean net accumulation rates in peatlands.

Environmental controls on δ13C variations of Sphagnum derived n-alkanes in the Dajiuhu peatland, central China

NASA Astrophysics Data System (ADS)

Huang, X.; Xue, J.; Wang, X.; WANG, H.; Meyers, P. A.; Qin, Y.; Gong, L.; Ding, W.

2012-12-01

Northern peatlands are one of the very important atmospheric carbon sinks and represent about 30% of the global soil organic carbon (Gorham, 1991). In peatland conditions, high water levels and consequent anoxia make them an important source of methane. A recent study revealed that methanotrophic bacteria growing on stems or in hyaline cells of Sphagnum can provide methane derived carbon for photosynthesis (Raghoebarsing et al., 2005). This interaction has been found to be globally prevalent in peat-moss ecosystems and can contribute up to 30% of carbon for Sphagnum photosynthesis (Kip et al., 2010). Due to the uptake of 13C-depleted methane-derived CO2 and the sensitivity of methane oxidizing bacteria to the surface wetness, the carbon isotopic signatures of Sphagnum derived lipids have the potential to be used as a proxy for the surface wetness in peatlands and hence as paleoclimate archives (Nichols et al., 2009). In this study, we report the δ13C variations of the Sphagnum derived n-C23 alkane in both fresh Sphagnum and surface peat samples in the Dajiuhu peatland, a small fen located in the Shennongjia forestry region, Hubei province, central China. The δ13C23 values of Sphagnum show a negative correlation with the water level, supporting the idea that that the carbon isotope fractionation of Sphagnum is mainly manifested by the diffusion resistance of CO2 in hyaline cells of Sphagnum. However, δ13C23 values of surface peats collected in Sphagnum dominated ecosystems display a positive relation with the water level when the water level is less than 30 cm. Such an inconsistency probably results from the higher potential for methane-oxidizing activity in the lower parts of Sphagnum in fen meadows. When the water level is higher than 30 cm, the influence of symbiotic methanotrophic bacteria on Sphagnum derived n-C23 alkane is weak or nearly absent. These findings provide direct evidence to support the hypothesis that the carbon isotopic signatures of Sphagnum derived lipids can be used as a proxy of surface wetness in peatlands. References Gorham, E., 1991. Northern peatlands: role in the carbon cycle and probable responses to climatic warming. Ecological Applications, 1, 182-195. Kip, N., van Winden, J.F., Pan, Y., et al., 2010. Global prevalence of methane oxidation by symbiotic bacteria in peat-moss ecosystems. Nature Geosciences 3, 617-621. Nichols, JE, Walcott, M, Bradley, R., et al., 2009. Quantitative assessment of precipitation seasonality and summer surface wetness using ombrotrophic sediments from an Arctic Norwegian peatland. Quaternary Research, 2009, 72: 443-451. Raghoebarsing, A.A., Smolders, A.J.P., Schmid, M.C., et al., 2005. Methanotrophic symbionts provide carbon for photosynthesis in peat bogs. Nature 436, 1153-1156.

Export of dissolved organic carbon and nitrogen from drained and re-wetted bog sites in Lower Saxony (Germany)

NASA Astrophysics Data System (ADS)

Frank, Stefan; Tiemeyer, Bärbel; Freibauer, Annette

2014-05-01

Today, nearly all peatlands in Germany are drained for agriculture, forestry and peat cutting. The export of dissolved organic carbon (C) and nitrogen (N) may be important for the overall C and N balances and affects downstream ecosystems. While drainage generally increases solute losses, there is nearly no C and N export data of raised bogs in Germany which can be used to evaluate both the impact of drainage associated with intensive land use and the re-wetting of peat cutting sites. In the "Ahlenmoor" (North-Western Germany), four sampling points were chosen. Three sampling points represent a deeply drained intensively used grassland at various scales ranging from a drainage pipe (DP, 0.08 ha) and a drainage ditch (DD, 6.8 ha) to a collector ditch (CD, 20 ha). The fourth sampling point (RW) is a former peat cutting site (23 ha) re-wetted 10 years ago. At this site, polder technique was used to establish water tables at the soil surface. Sampling and discharge measurements were conducted bi-weekly from June 2011 to June 2013. Water table levels were recorded with automatic pressure sensors, and rating curves between discharge and water levels were used to calculate continuous discharge values. Samples were analyzed for dissolved organic carbon (DOC), particulate organic carbon (POC), dissolved organic nitrogen (DON), ammonium (NH4+), nitrate (NO3-), sulphate (SO42-), pH, electric conductivity (EC) and specific UV absorbance (SUVA). The discharge did not vary strongly between the sampling points and was slightly lower in the second year. Concentrations of all measured solutes were higher at the intensive grassland (DP, DD and CD) than at the re-wetted site. Surprisingly, SUVA showed no difference between all sites, while the DOC to DON ratio was narrower at DP, DD and CD than at RW. This indicates an export of more degraded dissolved organic matter (DOM) from the drained area. At the grassland sites, no statistical differences were found between the three scales except for SO42-, NO3- and pH. Thus, the grassland shows rather homogenous export patterns over various spatial scales, and there seem to be no fast mineralization or degradation of the exported DOM during the initial stage of export. In total, average losses of DOC (457 kg ha-1 a-1) and POC (40 kg ha-1 a-1) from the drained area were nearly thrice as high as from the re-wetted site (124 and 73 kg ha-1 a-1). The total nitrogen losses were even more reduced by re-wetting and dominated at all sites by DON (19.1 kg ha-1 a-1 at the grassland sites, 3.9 kg ha-1 a-1 at the re-wetted site). NH4+ (drained: 5.2 kg ha-1 a-1, re-wetted: 0.8 kg ha-1 a-1) and NO3- (drained: 1.6 kg ha-1 a-1, re-wetted: not detectable) played a minor role. Overall, differences in the export could rather be explained by differences in solute concentration than in discharge.

Microform-related community patterns of methane-cycling microbes in boreal Sphagnum bogs are site specific.

PubMed

Juottonen, Heli; Kotiaho, Mirkka; Robinson, Devin; Merilä, Päivi; Fritze, Hannu; Tuittila, Eeva-Stiina

2015-09-01

Vegetation and water table are important regulators of methane emission in peatlands. Microform variation encompasses these factors in small-scale topographic gradients of dry hummocks, intermediate lawns and wet hollows. We examined methane production and oxidization among microforms in four boreal bogs that showed more variation of vegetation within a bog with microform than between the bogs. Potential methane production was low and differed among bogs but not consistently with microform. Methane oxidation followed water table position with microform, showing higher rates closer to surface in lawns and hollows than in hummocks. Methanogen community, analysed by mcrA terminal restriction fragment length polymorphism and dominated by Methanoregulaceae or 'Methanoflorentaceae', varied strongly with bog. The extent of microform-related variation of methanogens depended on the bog. Methanotrophs identified as Methylocystis spp. in pmoA denaturing gradient gel electrophoresis similarly showed effect of bog, and microform patterns were stronger within individual bogs. Our results suggest that methane-cycling microbes in boreal Sphagnum bogs with seemingly uniform environmental conditions may show strong site-dependent variation. The bog-intrinsic factor may be related to carbon availability but contrary to expectations appears to be unrelated to current surface vegetation, calling attention to the origin of carbon substrates for microbes in bogs. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Late-Holocene hydroclimate and atmospheric circulation variability in southern Patagonia: insights from triple stable isotopes (δ18O, δ13C, δD) of peat bog Sphagnum moss

NASA Astrophysics Data System (ADS)

Xia, Z.; Yu, Z.; Zheng, Y.; Loisel, J.; Huang, Y.

2017-12-01

The Southern Hemisphere Westerly Winds (SHWWs) exert important influences on regional and global climates, but their long-term behaviors and dynamics are still poorly understood but critical for projecting future changes. Here we present a 5,500-year record from a Sphagnum-dominated peat bog located on the lee side of the Andes at 54.2 °S in southern Patagonia—based on plant macrofossils, Sphagnum cellulose δ18O and δ13C, and lipid δD data—to document and understand the variability in hydroclimate and atmospheric circulation. There is a striking negative correlation between cellulose δ18O and the Southern Annular Mode (SAM) index over the last millennium; particularly the 2.5‰ negative shift of δ18O is concurrent with the observed positive trend in the SAM over the recent decades. The interval of Medieval Climate Anomaly (MCA, 850-600 yr BP) is characterized by a 2.5‰ negative shift of δ18O and low δ13C values, while the Little Ice Age (LIA, 500-300 yr BP) is characterized by a 2.5‰ positive shift of δ18O and high δ13C values. Furthermore, we find the largest negative shift of δ18O ( 3‰) at 2,300 yr BP, suggesting a significantly positive shift in the SAM. We interpret high Sphagnum abundance and high cellulose δ13C values to reflect great moss moisture conditions, while cellulose δ18O variations primarily reflect moisture sources and atmospheric circulation. During the positive phase of SAM (e.g., the MCA and recent decades), strengthened SHWWs enhance the rain-shadow effect, resulting in dry climate and 18O-depleted precipitation (low δ18O values) in the study region. During the negative phase of SAM (e.g., the LIA), weakened SHWWs reduce rain-shadow effect, resulting in wet climate and high δ18O values caused by increases in moisture contributions from the southerly and easterly flows that do not experience strong Rayleigh distillation process during air mass transports. Furthermore, coupling cellulose δ18O and lipid δD enables inverse calculation on the deuterium excess to understand the origin of atmospheric moisture. Our results provide new insights into the evolution of the SHWW and SAM during the late Holocene. We also use back-trajectory analysis equipped with moisture uptake algorithm to link moisture sources and trajectories with isotopic composition of precipitation in southern Patagonia.

The Effects of Peatland Plant Functional Types and Altered Hydrology on Porewater Chemistry in a Northern Bog

NASA Astrophysics Data System (ADS)

Daniels, A.; Kane, E. S.; Lilleskov, E. A.; Kolka, R. K.; Chimner, R. A.; Potvin, L. R.; Romanowicz, K. J.

2012-12-01

Northern wetlands, peatlands in particular, have been shown to store around 30% of the world's soil carbon and thus play a significant role in the carbon cycle of our planet. Carbon accumulation in peatlands is the result of retarded decomposition due to low oxygen availability in these water-logged environments. Changes in our planet's climate cycles are altering peatland hydrology and vegetation communities, resulting in changes in their ability to sequester carbon through increases in peat carbon oxidation and mineralization. To date, the consequences of altered hydrology and changes in vegetation communities, and their interactive effects on carbon storage, are not well understood. We have initiated a research plan that assesses the varying roles that water table variation and vegetation communities have on extracellular enzyme activity and labile carbon availability in porewater from an ombrotrophic bog. We assessed the effects of plant functional group (ericaceous shrubs, sedges, and bryophytes) and water table position on biogeochemical processes. Specifically, we measured dissolved organic carbon (DOC), total dissolved nitrogen (TDN), enzyme activity, organic acids, anions and cations, spectral indexes of aromaticity, and phenolic content in addressing our hypotheses of responses to climate change drivers. Research on these components will evaluate the relative importance of biology, water table, and their interactive affects on the porewater quality of peatlands. We hypothesized that oxygen availability will strongly influence decomposition in these systems but that this response will largely be mediated by changes in plant community and the enzymes associated with root exudates and mycorrhizae. To date, our data confirm vegetation and water table related patterns. Acetate and propionate concentrations in the sedge-dominated communities dropped significantly with depth and drainage, relative to the control and ericaceous treatments, which likely reflects changes in redox potential owing to physiological differences in sedges which contain aerenchyma cell, and a reduction in the products of anaerobic metabolism. DOC increased in the lowered water table treatments in all vegetation community types. Enzymatic activities have changed in response to water table level and vegetation community. While we have not detected significant levels of peroxidase enzymes in porewater, initial results indicate that hydrolase enzyme activities were higher in the sedge-dominated communities with a lowered water table. Through this research, we are hoping to advance our knowledge of the drivers behind peatland biogeochemistry and how ombrotrophic peat systems may respond to climate change influences.

Combining Carbon Accumulation and Hydroclimatic Variations Throughout the Holocene: Can we Detect a Climate Signal from Northeastern Canadian Boreal Peatlands ?

NASA Astrophysics Data System (ADS)

Garneau, M.; van Bellen, S.; Magnan, G.; Lamarre, A.; Thibault, A.

2013-12-01

In northeastern Canada, data on peatland development, carbon accumulation and hydroclimatic variations show changes throughout the Holocene period. Regional comparisons following south-north gradients from both western and eastern parts of the Québec province are used to evaluate the long-term processes influencing the peatlands carbon dynamics in this region of Canada. Seven different ecoclimatic subregions of the boreal biome distributed along two main geographic gradients (continental and maritime) have been characterized in terms of carbon accumulation and hydroclimatic variations. Results show an important maritime influence in terms of temperature (in particular through sea ice cover duration), relative humidity and wind exposure on peatland dynamics. In all regions, except in depressed areas, forests have first colonized the land following ice retreat and withdrawal of the marine waters. Peat accumulation has been initiated by paludification from 5500 cal BP mainly. Results show variations in the timing of trophic status transitions but there is a relative synchronic decrease in peat C accumulation in all regions from the Neoglacial cooling period. Cooler climatic conditions seem responsible for a decrease in biomass productivity and a rise in bog surface wetness due to lower evapotranspiration. Changes in hydroclimatic conditions may also have favored the development or expansion of pools and flarks at the peatland surfaces. These allogenic conditions also mediated by internal (autogenic) processes have been important factors controlling the long-term carbon dynamics of the studied peatlands. Impacts on carbon dioxide uptake and methane emissions through time require further considerations to evaluate the response of these systems to climate change.

Modeling the effects of hydrology on gross primary productivity and net ecosystem productivity at Mer Bleue bog

NASA Astrophysics Data System (ADS)

Dimitrov, Dimitre D.; Grant, Robert F.; Lafleur, Peter M.; Humphreys, Elyn R.

2011-12-01

The ecosys model was applied to investigate the effects of water table and subsurface hydrology changes on carbon dioxide exchange at the ombrotrophic Mer Bleue peatland, Ontario, Canada. It was hypothesized that (1) water table drawdown would not affect vascular canopy water potential, hence vascular productivity, because roots would penetrate deeper to compensate for near-surface dryness, (2) moss canopy water potential and productivity would be severely reduced because rhizoids occupy the uppermost peat that is subject to desiccation with water table decline, and (3) given that in a previous study of Mer Bleue, ecosystem respiration showed little sensitivity to water table drawdown, gross primary productivity would mainly determine the net ecosystem productivity through these vegetation-subsurface hydrology linkages. Model output was compared with literature reports and hourly eddy-covariance measurements during 2000-2004. Our findings suggest that late-summer water table drawdown in 2001 had only a minor impact on vascular canopy water potential but greatly impacted hummock moss water potential, where midday values declined to -250 MPa on average in the model. As a result, simulated moss productivity was reduced by half, which largely explained a reduction of 2-3 μmol CO2 m-2 s-1 in midday simulated and measurement-derived gross primary productivity and an equivalent reduction in simulated and measured net ecosystem productivity. The water content of the near-surface peat (top 5-10 cm) was found to be the most important driver of interannual variability of annual net ecosystem productivity through its effects on hummock moss productivity and on ecosystem respiration.

Alteration of the Copper-Binding Capacity of Iron-Rich Humic Colloids during Transport from Peatland to Marine Waters.

PubMed

Muller, François L L; Cuscov, Marco

2017-03-21

Blanket bogs contain vast amounts of Sphagnum-derived organic substances which can act as powerful chelators for dissolved iron and thus enhance its export to the coastal ocean. To investigate the variations in quantity and quality of these exports, adsorptive cathodic stripping voltammetry (CSV) was used to characterize the metal binding properties of molecular weight-fractionated dissolved organic matter (MW-fractionated DOM) in the catchment and coastal plume of a small peat-draining river over a seasonal cycle. Within the plume, both iron- and copper-binding organic ligands showed a linear, conservative distribution with increasing salinity, illustrating the high stability of peatland-derived humic substances (HS). Within the catchment, humic colloids lost up to 50% of their copper-binding capacity, expressed as a molar ratio to organic carbon, after residing for 1 week or more in the main reservoir of the catchment. Immediately downstream of the reservoir, the molar ratio [L 2 ]/[C org ], where L 2 was the second strongest copper-binding ligand, was 0.75 × 10 -4 when the reservoir residence time was 5 h but 0.34 × 10 -4 when it was 25 days. Residence time did not affect the carbon specific iron-binding capacity of the humic substances which was [L]/[C org ] = (0.80 ± 0.20) × 10 -2 . Our results suggest that the loss of copper-binding capacity with increasing residence time is caused by intracolloidal interactions between iron and HS during transit from peat soil to river mouth.

Anthropogenic and geomorphic controls on peatland dynamics in contrasting floodplain environments during the Holocene and its impact on carbon storage

NASA Astrophysics Data System (ADS)

Verstraeten, Gert; Broothaerts, Nils; Notebaert, Bastiaan

2016-04-01

Peatlands are an important store of carbon in terrestrial environments, and scientific interest in peatlands has increased strongly in the light of the recent global climatic changes. Much attention has been paid to peatland dynamics in extensive arctic and boreal wetlands or to blanket peat in temperate regions. Nevertheless, long-term dynamics of peat in alluvial wetlands in temperate regions remains largely underresearched. In this study, data from three contrasting environments were used to provide more insights in the anthropogenic and geomorphic controls on peatland dynamics. The results show a high variability in alluvial peatland dynamics between the different study sites. In the central Belgian Loess Belt, alluvial peatlands developed during the early Holocene but gradually disappeared from the Mid-Holocene onwards due to the gradual intensification of agricultural activities in the catchment and consequent higher sedimentation rates in the floodplain system. The end of peat growth is shown to be diachronous at catchment scale, ranging between 6500 and 500 cal a BP. The disappearance of the alluvial peatlands has important implications since it potentially reduces the storage of locally produced C. Nevertheless, it was shown that this reduced production of local C but was outbalanced by the burial of hillslope derived C. Also within the sandy catchments of the Belgian Campine region alluvial peatlands initiated in the early Holocene but, here, they abruptly disappeared in the Mid-Holocene before the onset of intense agricultural activities in the catchment. This suggests that for the sandy regions, anthropogenic impact on peatland dynamics is less important compared to natural factors. For these regions, the disappearance of alluvial peatland formation resulted in a sharp decline in alluvial carbon storage as there is no compensation through hillslope derived C input. For the upper Dee catchment in NE Scotland, Holocene carbon floodplain storage varies strongly along the river gradient as a result of varying geomorphic conditions and changes in hillslope-valley connectivity that control alluvial peatland formation. Overall, alluvial peatland dynamics are shown to be highly variable, in space, timing, rate of changes and controlling factors. This has important implications on C-storage studies and questions the possibilities of extrapolation of single site studies towards larger areas.

Temporal and Spatial Variation in Peatland Carbon Cycling and Implications for Interpreting Responses of an Ecosystem-Scale Warming Experiment

DOE PAGES

Griffiths, Natalie A.; Hanson, Paul J.; Ricciuto, Daniel M.; ...

2017-11-22

Here, we are conducting a large-scale, long-term climate change response experiment in an ombrotrophic peat bog in Minnesota to evaluate the effects of warming and elevated CO 2 on ecosystem processes using empirical and modeling approaches. To better frame future assessments of peatland responses to climate change, we characterized and compared spatial vs. temporal variation in measured C cycle processes and their environmental drivers. We also conducted a sensitivity analysis of a peatland C model to identify how variation in ecosystem parameters contributes to model prediction uncertainty. High spatial variability in C cycle processes resulted in the inability to determinemore » if the bog was a C source or sink, as the 95% confidence interval ranged from a source of 50 g C m –2 yr –1 to a sink of 67 g C m –2 yr –1. Model sensitivity analysis also identified that spatial variation in tree and shrub photosynthesis, allocation characteristics, and maintenance respiration all contributed to large variations in the pretreatment estimates of net C balance. Variation in ecosystem processes can be more thoroughly characterized if more measurements are collected for parameters that are highly variable over space and time, and especially if those measurements encompass environmental gradients that may be driving the spatial and temporal variation (e.g., hummock vs. hollow microtopographies, and wet vs. dry years). Together, the coupled modeling and empirical approaches indicate that variability in C cycle processes and their drivers must be taken into account when interpreting the significance of experimental warming and elevated CO 2 treatments.« less

Sphagnum-dominated bog systems are highly effective yet variable sources of bio-available iron to marine waters.

PubMed

Krachler, Regina; Krachler, Rudolf F; Wallner, Gabriele; Steier, Peter; El Abiead, Yasin; Wiesinger, Hubert; Jirsa, Franz; Keppler, Bernhard K

2016-06-15

Iron is a micronutrient of particular interest as low levels of iron limit primary production of phytoplankton and carbon fluxes in extended regions of the world's oceans. Sphagnum-peatland runoff is extraordinarily rich in dissolved humic-bound iron. Given that several of the world's largest wetlands are Sphagnum-dominated peatlands, this ecosystem type may serve as one of the major sources of iron to the ocean. Here, we studied five near-coastal creeks in North Scotland using freshwater/seawater mixing experiments of natural creek water and synthetic seawater based on a (59)Fe radiotracer technique combined with isotopic characterization of dissolved organic carbon by Accelerator Mass Spectrometry. Three of the creeks meander through healthy Sphagnum-dominated peat bogs and the two others through modified peatlands which have been subject to artificial drainage for centuries. The results revealed that, at the time of sampling (August 16-24, 2014), the creeks that run through modified peatlands delivered 11-15μg iron per liter creek water to seawater, whereas the creeks that run through intact peatlands delivered 350-470μg iron per liter creek water to seawater. To find out whether this humic-bound iron is bio-available to marine algae, we performed algal growth tests using the unicellular flagellated marine prymnesiophyte Diacronema lutheri and the unicellular marine green alga Chlorella salina, respectively. In both cases, the riverine humic material provided a highly bio-available source of iron to the marine algae. These results add a new item to the list of ecosystem services of Sphagnum-peatlands. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Temporal and Spatial Variation in Peatland Carbon Cycling and Implications for Interpreting Responses of an Ecosystem-Scale Warming Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffiths, Natalie A.; Hanson, Paul J.; Ricciuto, Daniel M.

Here, we are conducting a large-scale, long-term climate change response experiment in an ombrotrophic peat bog in Minnesota to evaluate the effects of warming and elevated CO 2 on ecosystem processes using empirical and modeling approaches. To better frame future assessments of peatland responses to climate change, we characterized and compared spatial vs. temporal variation in measured C cycle processes and their environmental drivers. We also conducted a sensitivity analysis of a peatland C model to identify how variation in ecosystem parameters contributes to model prediction uncertainty. High spatial variability in C cycle processes resulted in the inability to determinemore » if the bog was a C source or sink, as the 95% confidence interval ranged from a source of 50 g C m –2 yr –1 to a sink of 67 g C m –2 yr –1. Model sensitivity analysis also identified that spatial variation in tree and shrub photosynthesis, allocation characteristics, and maintenance respiration all contributed to large variations in the pretreatment estimates of net C balance. Variation in ecosystem processes can be more thoroughly characterized if more measurements are collected for parameters that are highly variable over space and time, and especially if those measurements encompass environmental gradients that may be driving the spatial and temporal variation (e.g., hummock vs. hollow microtopographies, and wet vs. dry years). Together, the coupled modeling and empirical approaches indicate that variability in C cycle processes and their drivers must be taken into account when interpreting the significance of experimental warming and elevated CO 2 treatments.« less

Fire Effects on Greenhouse Gas Emissions from Wetlands in the Yukon-Kuskokwim Delta, Alaska

NASA Astrophysics Data System (ADS)

Peter, D. L.; Bristol, E. M.; Mann, P. J.; Schade, J. D.; Natali, S.; Holmes, R. M.

2017-12-01

Climate change in increasing both fire frequency and fire intensity, especially in Arctic regions. Fire often leads to increased soil temperature, which increases the likelihood of permafrost thaw. Permafrost soils in northern latitudes store large amounts of carbon, and thawing of this permafrost will alter carbon cycling processes, which may substantially impact ecosystem processes in aquatic ecosystems. One potential consequence of altered aquatic ecosystem processes is changes in carbon emissions resulting from altered carbon inputs from thawing permafrost. Aquatic ecosystems are known to be hotspots of greenhouse gas emissions, so changes in greenhouse gas fluxes from them may have important impacts on global climate. In this work, we focused on CO2 and CH4 fluxes from peat plateau ponds, fens and bogs in the Yukon-Kuskokwim (YK) Delta in southwest Alaska. The YK Delta experienced unprecedented fires in summer 2015, presenting an opportunity to assess the impacts of fire on greenhouse gas fluxes from aquatic ecosystems. We sampled upland ponds, channel fens, bogs, and lowland ponds in sites that had burned in 2015 as well as from similar sites where there have been no recorded fires in the past 75 years. We found little difference in gas flux between aquatic sites in burned and unburned sites, with the exception of channel fens, which showed substantially higher fluxes of both CH4 and CO2 in burned sites. This is in contrast to similar measurements taken in summer 2016, when burned ponds showed consistently higher GHG fluxes, suggesting these increases were not sustained in sites other than channel fens. These results, if general, indicate the possibility that the response of aquatic ecosystems to fire may lead to positive feedbacks on climate change.

Upscaling Our Approach to Peatland Carbon Sequestration: Remote Sensing as a Tool for Carbon Flux Estimation.

NASA Astrophysics Data System (ADS)

Lees, K.; Khomik, M.; Clark, J. M.; Quaife, T. L.; Artz, R.

2017-12-01

Peatlands are an important part of the Earth's carbon cycle, comprising approximately a third of the global terrestrial carbon store. However, peatlands are sensitive to climatic change and human mismanagement, and many are now degraded and acting as carbon sources. Restoration work is being undertaken at many sites around the world, but monitoring the success of these schemes can be difficult and costly using traditional methods. A landscape-scale alternative is to use satellite data in order to assess the condition of peatlands and estimate carbon fluxes. This work focuses on study sites in Northern Scotland, where parts of the largest blanket bog in Europe are being restored from forest plantations. A combination of laboratory and fieldwork has been used to assess the Net Ecosystem Exchange (NEE), Gross Primary Productivity (GPP) and respiration of peatland sites in different conditions, and the climatic vulnerability of key peat-forming Sphagnum species. The results from these studies have been compared with spectral data in order to evaluate the extent to which remote sensing can function as a source of information for peatland health and carbon flux models. This work considers particularly the effects of scale in calculating peatland carbon flux. Flux data includes chamber and eddy covariance measurements of carbon dioxide, and radiometric observations include both handheld spectroradiometer results and satellite images. Results suggest that despite the small-scale heterogeneity and unique ecosystem factors in blanket bogs, remote sensing can be a useful tool in monitoring peatland health and carbon sequestration. In particular, this study gives unique insights into the relationships between peatland vegetation, carbon flux and spectral reflectance.

Fossil moss mites (Arthropoda: Oribatida): an introduction to their morphology and potential for Quaternary paleoecological interpretation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erickson, J.M.

1985-01-01

Although attention has been called to their presence as fossils in Quaternary lake and bog deposits a number of times, the moss mites (Arthropoda; Oribatida) have never been given serious attention during paleoecological work. This study is the first to demonstrate the quality and quantity of oribatid fossil material preserved in post-glacial lacustrine sediments. Oribatids have been identified from Jurassic rocks and from Tertiary ambers in Mexico and the Baltic Region. They are sclerotized, chelicerate, arachnids (Acari) which possess many features that make them readily identifiable from fossil material. Setae, tarsi, genital and anal plates, sensilla, notogastral pits and pores,more » and a wide variety of ornamentation are particularly useful. More than 5000 species in 700 genera occur worldwide. Most are less than 500..mu..m in size. Oribatids are often ecologically specific and may be assigned to restricted habitats. They do not fly and are thus unlikely to be found in sediments beyond their local ranges. Some species are lacustrine; many favor bog habitats. A large literature describes ecological preferences of extant species. More than 10,000 specimens of larval and adult mites have been taken from 72 samples of lake sediment, ranging from <14,700 to <2000 years in age. This report focuses on a dozen 10-gram samples which yielded more than 1300 specimens from 7 genera. Species of Hydrozetes and Limnozetes are abundant in lake sediments; these become rarer and are replaced in peats by a diverse fauna including species of Oripoda, Scapheremaeus, Sphaerozetes, Scheloribates, Magnobates(.), and unidentified taxa. Preservation of delicate setal hairs, genital plates and sensilla allows ready generic identification. SEM photomicrographs serve to illustrate the quality of preservation and the morphologically important features by way of introduction to this under-utilized group.« less

The sensitivity of peat soil and peatland vegetation to drought: release of dissolved organic carbon (DOC) on rewetting

NASA Astrophysics Data System (ADS)

Ritson, Jonathan; Graham, Nigel; Templeton, Michael; Freeman, Christopher; Clark, Joanna

2015-04-01

Organic rich peat soils are a major store of carbon worldwide. Their existence is predicated on high year-round water tables which create an anoxic environment, thus limiting decay, and also to the recalcitrance of plant litter (dead plant material) commonly found in peatland areas. Climate change threatens the stability of peat soils by altering the biogeochemical cycles which control plant decay, lowering water tables so that oxic degradation can occur and by changing habitat niches such that less recalcitrant species can thrive in peatlands. One of the major fluxes of carbon from peatlands is through dissolved organic carbon (DOC) in surface waters. As peatland areas in the UK are often used as source waters for drinking water supply this presents a problem to water utilities as DOC must be effectively removed to limit colour, odour and the formation of potentially carcinogenic by-products on disinfection. Changes in catchment vegetation may occur due to climate change, nutrient deposition and changing bioclimatic envelopes. How different peatland vegetation contribute to DOC flux and how this may change in the future is therefore of interest. A six week laboratory simulation was performed on typical peatland litter (Sphagnum spp., Calluna vulgaris, Molinea caerulea, Juncus effusus) and a peat soil collected from Exmoor National Park, UK. The simulation monitored DOC flux from the decaying litter/soil and considered the impact of different drought severities using the 50th, 25th, 10th and 5th percentiles of the mean July/August monthly rainfall for Exmoor. On rewetting following the drought, all sources produced significantly different amounts of DOC (Tukey HSD p<0.05) in the order Molinia>Juncus>Calluna>Sphagnum>peat. The source also had a significant (ANOVA p<0.001) effect on coagulation removal efficiency, a typical method of removing DOC during drinking water treatment, with Juncus DOC proving the easiest to remove whilst Sphagnum DOC was the most difficult. Sphagnum DOC had the lowest ratio of humic-like to protein-like fluorescence, which is indicative of DOC which is poorly removed by coagulation. An interactive effect was noted between DOC source and the drought treatment which was explored further using a one-way ANOVA with a Holm-Šidák correction. This suggested peat will produce significantly more DOC when affected by drought (p=0.010), possibly explained by increased oxygenation engaging the 'enzymatic latch' mechanism. A similar analysis was performed on the interaction between drought and DOC source for the specific UV absorbance at 254nm (SUVA) value (a measure of aromaticity). This suggested that Molinea caerulea produces DOC of significantly (p=0.001) higher aromaticity following periods of drought. Comparisons between drought and DOC source factors suggest the source in more important than climatic conditions of decay which is consistent with our previously published findings. These results have implications for marginal peatlands which may be at risk from increased water table drawdown in the future as climate changes and where Molinea caerulea, typically a fen species, is encroaching on bog communities.

Paludiculture as a chance for peatland and climate: the greenhouse gas balance of biomass production on two rewetted peatlands does not differ from the natural state

NASA Astrophysics Data System (ADS)

Günther, Anke; Huth, Vytas; Jurasinski, Gerald; Albrecht, Kerstin; Glatzel, Stephan

2015-04-01

In Europe, rising prices for farm land make it increasingly difficult for government administrations to compete with external investors during the acquisition of land for wetland conservation. Thus, adding economic value to these, otherwise "lost", areas by combining extensive land use with nature conservation efforts could increase the amount of ground available for wetland restoration. Against this background, the concept of paludiculture aims to provide biomass for multiple purposes from peatlands with water tables high enough to conserve the peat body. However, as plants have been shown to contribute to greenhouse gas exchange in peatlands, manipulating the vegetation (by harvesting, sowing etc.) might alter the effect of the restored peatlands on climate. Here, we present greenhouse gas data from two experimental paludiculture systems on formerly drained intensive grasslands in northern Germany. In a fen that has been rewetted more than 15 years ago three species of reed plants were harvested to simulate biomass production for bioenergy and as construction material. And in a peat bog that has been converted from drained grassland to a field with a controlled water table around ground surface Sphagnum mosses were cultivated to provide an alternative growing substrate for horticulture. In both systems, we determined carbon dioxide, methane, and nitrous oxide exchange using closed chambers over two years. Additionally, water and peat chemistry and environmental parameters as recorded by a weather station were analyzed. Both restored peatlands show greenhouse gas balances comparable to those of natural ecosystems. Nitrous oxide was not emitted in either system. Fluctuations of the emissions reflect changes in weather conditions across the study years. In the fen, relative emission patterns between plant species were not constant over time. We did not find a negative short-term effect of biomass harvest or Sphagnum cultivation on net greenhouse gas balances. Therefore, paludiculture may likely provide a possibility to add economic value to restored peatlands while retaining the positive effects of rewetting for greenhouse gas mitigation.

The effects of ecological restoration on CO2 fluxes from a climatically marginal upland blanket bog

NASA Astrophysics Data System (ADS)

Dixon, Simon; Qassim, Suzane; Rowson, James; Worrall, Fred; Evans, Martin

2013-04-01

A legacy of gully incision, deposition of industrially-derived aerial pollutants, inappropriate management and wildfire has left large expanses of the topographic Bleaklow Plateau (Peak District National Park, England, UK) bare of vegetation and susceptible to massive erosion of the peat soils. The consequence of such degradation has been to decrease the capacity of the peatland on the plateau to provide important ecosystem services including; loss of net C sink function, discolouration of surface waters, mobilisation to surface waters of stored heavy metals and infilling of upland reservoirs with peat-derived sediment. In response to on-going and worsening degradation a programme of ecological restoration has been undertaken. Restoration methods include: seeding with a lawn grass mix; liming; fertilisation; slope stabilisation; and gully blocking. This talk will present data from a five-year, observational-study of CO2 fluxes from eight sites, with four sites sampling different restoration treatments and four sampling bare and least disturbed areas. The results of the analysis reveal that sites with revegetation alongside slope stabilisation were most productive and were the largest net (daylight hours) sinks of CO2. Unrestored, bare sites, while having relatively low gross fluxes of CO2 were the largest net sources of CO2. Revegetation without slope stabilisation took longer (~18 months) to show an impact on CO2 flux in comparison to the sites with slope stabilisation. Binary logistic regression indicated that a ten centimetre increase in water table depth decreases the odds of observing a net CO2 sink, on a given site, by up to 30%. Sites with slope stabilisation were between 5-8x more likely to be net CO2 sinks than the bare sites. Sites without slope stabilisation were only 2-2.3x more likely to be net CO2 sinks compared to the bare sites. The most important conclusion of this research is that revegetation appears to be effective at increasing the likelihood of net CO2 behaviour on degraded, climatically marginal blanket peat, with revegetation alongside slope stabilisation having the greatest impact.

The use of Sphagnum cellulose oxygen isotope ratios in ombrotrophic peatlands as a proxy for paleoclimate.

NASA Astrophysics Data System (ADS)

Taylor, M.; Pendall, E.; Jackson, S.; Booth, R. K.; Nichols, J. E.; Huang, Y.

2006-12-01

Developing proxies for discerning paleoclimate that are independent of the pollen record can provide insight into various aspects of climate variability and improve confidence in the interpretation of climate-vegetation interactions. To date, proxies including plant macrofossils, humification indices, testate amoebae, and ratios of n-alkane abundances have been used to infer past climate variability from temperate ombrotrophic peatlands in upper Midwestern North America. These proxies are used to infer past changes in surface-moisture conditions, which in ombrotrophic peatlands is primarily a function of precipitation and temperature. This study investigates the potential uses of stable oxygen isotopes to complement hydrologic proxies. δ18O of surface water and Sphagnum moss cellulose from bogs throughout North America indicates a correlation between average growing season temperatures and δ18O-values. The existence of a modern temperature signal in moss cellulose suggests that δ18O-derived records will not only complement paleohydrological records, but also help assess relative changes in precipitation and temperature. Humification and testate amoebae data from two cores taken from Minden and Irwin Smith Bogs in central and northeastern Michigan have recorded several extreme drought events during the Holocene, including one at 1000 YBP. Comparison of δ18O-values of picked Sphagnum remains to down-core humification and testate amoebae data suggest good temporal correspondence, with the δ18O-values around 1000 YBP indicating a warmer growing season.

The use of Ground Penetrating Radar in coastal research, archeaological investigations, lake studies, peat layer measurments and applied research in Estonia

NASA Astrophysics Data System (ADS)

Vilumaa, Kadri; Tõnisson, Hannes; Orviku, Kaarel

2014-05-01

Ground Penetrating Radar (GPR) is mainly used for scientific research in coastal geology in the Institute of Ecology at Tallinn University. We currently use SIR-3000 radar with 100, 270 , 300 and 500 MHz antennae. Our main targets have been detecting the thickness of soil and sand layers and finding out the layers in coastal sediments which reflect extreme storm events. Our GPR studies in various settings have suggested that the internal structures of the ridge-dune complexes are dominated by numerous layers dipping in various directions. Such information helps us to reconstruct and understand prevailing processes during their formation (e.g. seaward dipping lamination in coastal ridge-dune complexes indicating cross-shore and wave-induced transport of the sediments). Currently, we are trying to elaborate methodology for distinguishing the differences between aeolian and wave transported sediments by using GPR. However, paludified landscapes (often covered by water), very rough surface (numerous bushes and soft surface), moderate micro topography has slowed this process significantly. Moreover, we have been able to use GPR during the winter period (applied on ice or snow) and compare the quality of our results with the measurements taken during the summer period. We have found that smooth surface (in winter) helps detecting very strong signal differences (border between different sediment types - sand, peat, silt, etc.) but reduces the quality of the signal to the level where the detection of sedimentation patterns within one material (e.g. tilted layers in sand) is difficult. We have carried out several other science-related studies using GPR. These studies include determining the thickness of peat layer in bogs (to calculate the volume of accumulated peat or to find most suitable locations for coring), measuring the thickness of mud and gyttja layer in lakes (to find most suitable locations for coring, reconstructing initial water level of the lake or calculating the volume of stored carbon in the lake). Additionally, we have done several archaeology-related research including the search of buried city walls and caves (Tallinn old town), buried Viking ship (Saaremaa Island) and several other archaeological objects. We have also done some applied studies including the search of underground power cables, heating pipes, melioration systems, ammunition warehouses (from World War II) and buried ammunition from the military training fields. Aknowledgement: The authors acknowledge COST for funding Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar', supporting part of this work.

Seven centuries of atmospheric Pb deposition recorded in a floating mire from Central Italy

NASA Astrophysics Data System (ADS)

Zaccone, Claudio; Lobianco, Daniela; D'Orazio, Valeria; Miano, Teodoro M.; Shotyk, William

2016-04-01

Floating mires generally consist of emergent vegetation rooted in highly organic buoyant mats that rise and fall with changes in water level. Generally speaking, the entire floating mass (mat) is divided into a mat root zone and an underlying mat peat zone. Floating mires are distributed world-wide; large areas of floating marsh occur along rivers and lakes in Africa, the Danube Delta in Romania, the Amazon River in South America, and in the Mississippi River delta in USA, whereas smaller areas occur also in The Netherlands, Australia and Canada. While peat cores from ombrotrophic bogs have been often (and successfully) used to reconstruct changes in the atmospheric deposition of several metals (including Pb), no studies are present in literature about the possibility to use peat profiles from floating mires. To test the hypothesis that peat-forming floating mires could provide an exceptional tool for environmental studies, a complete, 4-m deep peat profile was collected in July 2012 from the floating island of Posta Fibreno, a relic mire in the Central Italy. This floating island has a diameter of ca. 30 m, a submerged thickness of about 3 m, and the vegetation is organized in concentric belts, from the Carex paniculata palisade to the Sphagnum palustre centre. The whole core was frozen cut each 1-to-2 cm (n =231), and Pb determined by quadrupole ICP-MS (at the ultraclean SWAMP lab, University of Alberta, Canada) in each sample throughout the first 100 cm, and in each odd-numbered slice for the remaining 300 cm. The 14C age dating of organic sediments (silty peat) isolated from the sample at 385 cm of depth revealed that the island probably formed ca. 700 yrs ago. Lead concentration trend shows at least two main zones of interest, i.e., a clear peak (ranging from 200 to 1600 ppm) between 110-115 cm of depth, probably corresponding to early 1960's - late 1970's, and a broad band (80-160 ppm) between 295-320 cm of depth, corresponding to approximately AD 1480-1650. Lead concentrations were normalized to those of Th, a conservative, lithophile element often used as an indicator of the abundance of mineral particles. Crustal enrichment factor values, calculated by normalizing the Pb/Th ratio in peat samples to the corresponding ratio for the Upper Continental Crust, clearly show that almost all the Pb reaching this floating isle in the last seven centuries is of anthropogenic origin. In particular, while the big peak around 100-115 cm of depth is associated with that of Sb, the band around 300 cm characterized also the trend of several other major and trace elements (i.e., Ag, Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sr, Th, Tl, U, V, Y, Zn) with the exception of Sb. Although γ-spectrometry measurement (210Pb, 137Cs and 241Am) for the first 100 cm of this core is still on-going, at the best of our knowledge, this work may provide the first Pb chronology obtained from a (4 m) deep floating mire. Furthermore, it is to note that a) this floating mire could consist of the southernmost European population of Sphagnum, and b) this core shows a great potential to be used as archive of environmental changes, especially considering its high resolution (1 cm = 0.5 yr in the first 100 cm, and 2-2.5 yrs in the remaining 300 cm of depth). The Authors thank the Municipality of Posta Fibreno, Managing Authority of the Regional Natural Reserve of Lake Posta Fibreno, for allowing peat cores sampling.

National Program for Inspection of Non-Federal Dams. New Pond Dam (MA 00779), Massachusetts Coastal Basin, Easton, Massachusetts. Phase I Inspection Report.

DTIC Science & Technology

1981-07-01

formerly provided irrigation water for the Hammond-Fuller i cranberry bogs. At the present the reservoir continues to service some bogs approximately 2...there are few depressions or irregularities. Vegetation along the edges of the crest consist of short brush, scattered trees up to 22 in. diameter...dam formerly provided irrigation water for cranberry bogs downstream and continues to service some bogs although the owners of the bogs have no

Effects of peatland drainage on water quality: a case study of the shallow blanket bogs of Exmoor, UK

NASA Astrophysics Data System (ADS)

Grand-Clement, E.; Luscombe, D.; Le Feuvre, N.; Smith, D.; Anderson, K.; Brazier, R. E.

2012-04-01

Peatlands are widely represented in the South West of England (i.e. Exmoor, Dartmoor and Bodmin moors), but their existence is currently under threat due to both climate change and the impact of historical human activities. Peat cutting and intensive drainage for agricultural reclamation in the 19th and 20th century, have modified the hydrological behaviour of these shallow peats and dried out the upper layers, causing oxidation, erosion and vegetation change. Such anthropogenic impacts directly affect the storage of carbon, but also the provision of other ecosystem services, such as the supply of drinking water, and the support of specific and rare habitats. Blocking drainage ditches to restore the hydrological behaviour of peatlands has mostly been undertaken in the North of England, but to date, little is still known about the consequences of such management approaches on the overall Carbon stocks. The need to monitor restoration of peatlands in the South West of England arises due to the specific characteristics of the peat - it is often shallower than more northerly peat and dominated by Purple Moor Grass. In addition, and in part because of the shallowness of the resource, the peat has been damaged differently, often with very dense networks of hand-cut ditches which behave as highly efficient drainage networks. Most importantly, their location at the southernmost margin of the UK peatlands' geographical extent makes them extremely vulnerable to climate change, and so it is hypothesised that monitoring of these peatlands may provide an 'early warning system' for climatic impacts that affect more northerly sites in years to come. This study focuses upon the current impact of peatland degradation on water quality on Exmoor. Our experimental approach employs detailed, high resolution monitoring of selected ditches that are representative of damaged conditions on Exmoor, from small- (30 x 30cm ditches) through medium- (50x50cm), large- (1-2m ditches) and finally headwater catchment-scales. Flow monitoring has been in place at all scales since November 2010. Flow proportional water samples were collected during a range of events throughout winter 2011-2012 and analysed for Dissolved Organic Carbon (DOC), Particulate Organic Carbon (POC), pH and colour. These variables were identified as critical, both in terms of carbon cycling and for costly water treatment that currently takes place downstream. Results were examined spatially in relation to drain sizes and magnitude/frequency of event, to improve our understanding of carbon losses in streams from damaged peatlands and further estimate the potential for improvement that can be expected after restoration. Data presented here focus on the DOC and colour and demonstrate the importance of understanding across different scales of ditch and understanding the effects of the magnitude/frequency of events that are observed prior to restoration of the system.

Quantifying the Microbial Utilization of Methanogenesis and Methane Loss from Northern Wetlands

NASA Astrophysics Data System (ADS)

Corbett, J. E.; Tfaily, M.; Burdige, D.; Glaser, P. H.; Chanton, J.

2014-12-01

The importance of methanogenesis and percent of methane loss from the subsurface porewater in various northern wetland sites was quantified with isotope-mass balance equations. With equimolar amounts of CO2 and CH4 produced from methanogenesis, the amount of dissolved CO2 produced from methanogenesis as compared to other decomposition processes can be calculated and is equivalent to the amount of CH4 before loss due to ebullition, plant-mediated transport, and diffusion. This method was applied to porewater samples collected from various locations within permafrost collapse-scar bogs and northern peatlands. From the peatland sites, bogs produced less CO2-meth than fens (2.9 ± 1.3 mM and 3.7 ± 1.4 mM, respectively). Methanogenesis was a more utilized decomposition process in the bogs than the fens. However, greater amounts of CO2-meth found in fen sites was most likely due to the presence of more labile organic substrates resulting in greater overall production. More CH4 was lost in fens (89 ± 2.8%) than bogs (82 ± 5.3%) from plant-mediated transport as fens are dominated by vascular plants (Carex) while bogs are dominated by Sphagnum mosses. In permafrost sites, mid-bogs produced twice the amount of CO2-meth as bog moats (1.6 ± 0.63 mM and 0.82 ± 0.20 mM, respectively). Less methanogenesis was found in bog moats as recently thawed organic matter is exposed to initial decomposition processes and methane production grows over time. A similar amount of CH4 was lost from bog moats as mid bogs (63 ± 7.0% and 64 ± 9.3%, respectively) likely due to the greater density of vascular plants found within a bog moat.

[Trace element supply to ruminants in the German Democratic Republic. 2. Supply of copper].

PubMed

Anke, M; Groppel, B; Lüdke, H; Grün, M; Kleemann, J

1975-06-01

The supply of copper to ruminants as influenced by and depending on the geological origin of soils was investigated in different parts of the GDR by using the hair test. Red clovers (meadow clover and field clover) were used as indicator plants. The following results were obtained: Data on the Cu content of clovers grown on soils of the same geological origin were found to correlate with r = 0,81. After eliminating the effects of Cu antagonists resulting from industrial pollution it was possible to establish numerical relations (B = 0.39 and B = 0.89) between the relative values (specific for the particular location) for the Cu content of the indicator plants and the percentage of cows suffering from Cu deficiencies (6.0 and 5.0 ppm Cu in hair). The lowest percentages of Cu supply to the ruminants (established on the basis of the Cu content of red clovers) were found on diluvial sandy soils, glacial loams and peat and bog soils whereas the highest percentages of Cu were found on weathered soils (of phyllite, gneiss, shell limestone, red marl soils and porphyry). Secondary Cu deficiencies in ruminants may arise, independent of the geological origin of the soil material, in places exposed to the main direction of the winds from major industrial areas (emission of SO2, Cd and Mo). Due to primary and/or secondary deficiencies the supply of Cu to ruminants in various locations (syenite, granite, red sandstone, gneiss, loess; peat soils, diluvial sandy soils) may be insufficient. A detailed description is given of areas where Cu deficiency is likely to occur and recommendations are given on how to use mineral mixtures containing a high proportion of Cu (1.00 g Cu per kg).

Atmospheric flux, transport and mass balance of (210)Pb and (137)Cs radiotracers in different regions of Romania.

PubMed

Begy, R Cs; Kovacs, T; Veres, D; Simon, H

2016-05-01

This study focuses on the determination of (210)Pb and (137)Cs fluxes from different areas in Transylvania, Romania and on the determination of transport and mass balance within the lacustrine system of Red Lake. In order to achieve this, samples were taken from six different locations (Bihor County area, Ighiel area, Red Lake area, Mluha Peatbog, Mohos Peatbog and Zanoaga Rosie Peat bog in the Semenic Mountains) throughout Romania, these being compared to the values of the Danube Delta area. The activity concentrations of the soil samples were measured by gamma spectrometry (HPGe detector) for both (210)Pbtotal, (210)Pbsup ((226)Ra) and (137)Cs, while peat samples were measured by both alpha ((210)Po) spectrometry (PIPS detectors) as well. The mean value for the (210)Pb flux was measured in the Danube Delta region (42±8Bqm(-2) yr(-1)), while the highest was measured in the Semenic Peatbog (227±54Bqm(-2) yr(-1)); the average being 132±8Bqm(-2) yr(-1). In case of (137)Cs the mean was 298±3Bqm(-2) yr(-1), maximum being 1683±15Bqm(-2) yr(-1) in case of Ighiel area and minimum being 32±1Bqm(-2) yr(-1) in the Danube Delta region. In case of the Red Lake, from the total inventory of 410±23Bqm(-2) yr(-1) in the sediments, the loss by outflows is 100±12Bqm(-2) yr(-1), the catchment to lake transfer factor being 0.84%. Copyright © 2016 Elsevier Ltd. All rights reserved.

Habitat heterogeneity and connectivity shape microbial communities in South American peatlands

PubMed Central

Oloo, Felix; Valverde, Angel; Quiroga, María Victoria; Vikram, Surendra; Cowan, Don; Mataloni, Gabriela

2016-01-01

Bacteria play critical roles in peatland ecosystems. However, very little is known of how habitat heterogeneity affects the structure of the bacterial communities in these ecosystems. Here, we used amplicon sequencing of the 16S rRNA and nifH genes to investigate phylogenetic diversity and bacterial community composition in three different sub-Antarctic peat bog aquatic habitats: Sphagnum magellanicum interstitial water, and water from vegetated and non-vegetated pools. Total and putative nitrogen-fixing bacterial communities from Sphagnum interstitial water differed significantly from vegetated and non-vegetated pool communities (which were colonized by the same bacterial populations), probably as a result of differences in water chemistry and biotic interactions. Total bacterial communities from pools contained typically aquatic taxa, and were more dissimilar in composition and less species rich than those from Sphagnum interstitial waters (which were enriched in taxa typically from soils), probably reflecting the reduced connectivity between the former habitats. These results show that bacterial communities in peatland water habitats are highly diverse and structured by multiple concurrent factors. PMID:27162086

Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago

NASA Astrophysics Data System (ADS)

Eichler, A.; Gramlich, G.; Kellerhals, T.; Tobler, L.; Rehren, Th.; Schwikowski, M.

2017-01-01

The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200-800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700-50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bridgham, Scott D.; Keller, Jason K.; Zhuang, Qianlai

This project was funded from June 15, 2012 through June 15, 2015, with a no-cost extension until Sept. 15, 2016. Our project focused on a whole-ecosystem warming and enhanced atmospheric CO 2 experiment in the S1 Bog in Marcell Experimental Forest in northern Minnesota, USA called “Spruce and Peatland Responses Under Climatic and Environmental Change” (SPRUCE; http://mnspruce.ornl.gov). Construction of substantial infrastructure required for these treatments was beyond our control and led to a staggered initiation of experimental treatments at this site. Deep peat heating (DPH) was instituted in June 2014, whole-ecosystem warming began in August 2015, and the CO 2more » enhancement began in June 2016. Prior to the initiation of the experimental treatments, we completed a large amount of research to better understand factors controlling anaerobic carbon (C) cycling, and particularly methane (CH 4) dynamics, in northern peatlands in an effort to put the SPRUCE project in a broader context. We additionally focused extensively on the DPH treatment, which provided a unique opportunity to isolate warming effects on the vast reservoir of permanently anaerobic C stored in peatlands below the water table.« less

Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago.

PubMed

Eichler, A; Gramlich, G; Kellerhals, T; Tobler, L; Rehren, Th; Schwikowski, M

2017-01-31

The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200-800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700-50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.

Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago

PubMed Central

Eichler, A.; Gramlich, G.; Kellerhals, T.; Tobler, L.; Rehren, Th.; Schwikowski, M.

2017-01-01

The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200–800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700–50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures. PMID:28139760

Fire and Smoke in Western Russia on August 4, 2010

NASA Image and Video Library

2017-12-08

NASA image acquired August 4, 2010 Intense fires continued to rage in western Russia on August 4, 2010. Burning in dry peat bogs and forests, the fires produced a dense plume of smoke that reached across hundreds of kilometers. The Moderate Resolution Imaging Spectroradiometer (MODIS) captured this view of the fires and smoke in three consecutive overpasses on NASA’s Terra satellite. The smooth gray-brown smoke hangs over the Russian landscape, completely obscuring the ground in places. The top image provides a close view of the fires immediately southeast of Moscow, while the lower image shows the full extent of the smoke plume. To read more about this image go to: earthobservatory.nasa.gov/IOTD/view.php?id=45046 To view the high res go here: NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team at NASA GSFC. NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Fire and Smoke in Western Russia on August 4, 2010 [high res

NASA Image and Video Library

2017-12-08

NASA image acquired August 4, 2010 Intense fires continued to rage in western Russia on August 4, 2010. Burning in dry peat bogs and forests, the fires produced a dense plume of smoke that reached across hundreds of kilometers. The Moderate Resolution Imaging Spectroradiometer (MODIS) captured this view of the fires and smoke in three consecutive overpasses on NASA’s Terra satellite. The smooth gray-brown smoke hangs over the Russian landscape, completely obscuring the ground in places. The top image provides a close view of the fires immediately southeast of Moscow, while the lower image shows the full extent of the smoke plume. To read more about this image go to: earthobservatory.nasa.gov/IOTD/view.php?id=45046 NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team at NASA GSFC. NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Frozen peatlands: carbon store and the climate change

NASA Astrophysics Data System (ADS)

Ogneva, Olga; Matyshak, George; Tarkhov, Matvey

2017-04-01

Peatlands soils in the northern permafrost region store approximately 40% of total Earth's soils carbon. These soils develop under the influence of cryogenic processes especially such as freeze-thaw and cryoturbations. Climate change predictions suggest that the frequency of soil freeze-thaw cycles (FTCs) will increase in cool temperate and other high-latitude regions. This trend may cause a response in organic matter decomposition rate - that will result in significant changes of greenhouse gases emission (CO2, CH4). For further predictions improvement of soils response to global climate changes it is necessary to estimate the impact of FTCs in permafrost soils on organic matter decomposition. We investigated the effects of FTCs on microbial biomass, basal respiration, metabolic quotient and dissolved organic matter (DOM) content (carbon - DOC and nitrogen - DON) in frozen peatlands soils by laboratory modelling experiment. Frozen peatlands from the north of Western Siberia in Nadym area (N65°19', E72°53'), in a zone of discontinuous permafrost were studied. The soil cover of these formations is represented by a complex of Typic Histoturbels (Turbic Cryosol) and Typic Historthels (Cryic Histosols). Peat profiles of both soil types were divided into horizons due to decomposition degree (from 15 to 55-60%), age (from 1000 to 5700 yrs) and botanic composition (oligotrophic, mesotrophic, eutrophic). During the experiment, first group of samples of peat horizons (field moisture content) were subjected for 10 times to 3-day FTCs at the temperature of -10 and +4 ° C. In the second group of peat samples were incubated at +4 ° C (with no freeze-thaw). It was established that all studied microbial properties were inversely proportional with decomposition degree of peat, except metabolic quotient. Our results illustrate that microbial activity, estimated by BR, shows resistance to FTCs and doesn't significantly differ after FTCs an average. Microbial biomass (carbon and nitrogen) as well as BR doesn't differ too. The most intensive response to FTCs shows DOM content value which was 1.5 times higher on average in samples after FTCs in comparison with control samples. We suppose that increase of FTCs frequency in soil will result in significant acceleration mineralization of peat. Because these processes exert disruptive effects on soil organic matter, provide converting carbon from pool into forms available for microbial communities, thus involving stored carbon into the carbon turnover.

Elevated Nitrogen Deposition from Alberta Oil Sands Development Stimulates Phosphatase Activity in Dominant Sphagnum Moss Species

NASA Astrophysics Data System (ADS)

Kashi, N. N.; Wieder, R.; Vile, M. A.

2013-12-01

Emissions of NOx associated with Alberta oil sands (AOS) development are leading to locally elevated atmospheric N deposition, in a region where background N deposition has been historically quite low (< 1 kg/ha/yr). This elevated N deposition has the potential to alter the ecosystem structure and function of nutrient-poor boreal peatlands. Nitrogen enrichment may alter soil microbial activity, which could be manifested in changes in extracellular enzyme activities. Since 2011, we have been experimentally adding N as NH4NO3 in simulated precipitation at 0, 5, 10, 15, 20, and 25 kg N ha/yr/ plus no-water controls to a boreal bog and a poor fen (3 replicate plots per treatment). In 2013, acid phosphatase activities in living plant capitulum of Sphagnum angustifolium, Sphagnum fuscum, and Sphagnum magellanicum were quantified in June and July using 4-methyumbelliferylphosphate and fluorescence detection of the enzymatically released methylumbelliferone (MUF). Phosphatase activities did not differ with N treatment for S. angustifolium in the bog (p=0.3409) or the poor fen (p=0.0629), or for S. fuscum in the bog (p=0.1950), averaging 35.0 × 0.7, 61.6 × 1.2, and 41.6 × 0.9 μmol MUF/g DWT/hr, respectively. For S. fuscum in the poor fen, phosphatase activities differed between N treatments (p=0.0275), ranging 40.6 × 1.1 μmol MUF/g DWT/hr in the control plots to 73.7 × 2.0 μmol MUF/g DWT/hr in the 5 kg/ha/yr N treatment plots; increasing N deposition did not result in a gradual change in enzyme activity. On the other hand, S. magellanicum phosphatase activities differed between N treatments (p=0.0189) and showed a pattern of generally increasing activity with increasing N deposition (37.4 × 0.5 μmol MUF/g DWT/hr in control plots; 97.9 × 4.5 μmol MUF/g DWT/hr in the 25 kg/ha/yr N treatment plots). The differing phosphatase responses between these dominant Sphagnum species suggest unique differences in nutrient balance and/or microbial activity. Combining the three moss species and weighting by their abundances within each plot (percent cover), phosphatase activities differed between N treatments in the bog (p=0.0388) and the poor fen (p=0.0005), with the latter exhibiting a clear increase in enzyme activity with increasing N deposition, and a doubling of phosphatase activity between the control plots and the 25 kg/kg/yr N deposition treatment. Although the three moss species responded differently, at the plot scale, increasing N deposition stimulated phosphatase activity, suggesting that microbial enzyme activity in peat is sensitive to increasing N deposition from oil sands development, with potential consequences for peatland nutrient cycling.

Natural bog pine ecosystem in southern Germany is a steady and robust sink of CO2 but a minor source of CH4

NASA Astrophysics Data System (ADS)

Hommeltenberg, Janina; Schmid, Hans Peter; Droesler, Matthias; Werle, Peter

2013-04-01

Natural peatland ecosystems sequester carbon dioxide. They do this slowly but steadily, but also emit methane in small rates. Thus peatlands have both positive and negative greenhouse gas balance impacts on the climate system due to their influence on atmospheric CO2 and CH4 concentration. We present data of net ecosystem CO2 exchange (NEE) of almost three years (July 2010 to March 2013) and of methane fluxes over a period of nine months (July 2012 to March 2013), measured by eddy covariance technique in the bog forest "Schechenfilz". The site (47°48' N; 11°19' E, 590 m a.s.l.) is an ICOS-ecosystems associate site, located in the pre-alpine region of southern Germany, where a natural Pinus mugo rotundata forest grows on an undisturbed, almost 6 m thick peat layer. The slow growing bog pines and their low rates of carbon sequestration, in combination with high water table and thus low availability of oxygen, lead to low carbon dioxide fluxes. Photosynthesis as well as soil respiration are considerably attenuated compared to upland sites. Additionally, the high soil water content is damping the impact of dry and hot periods on CO2 exchange. Thus the CO2 balance is very robust to changing environmental parameters. While the CO2 exchange is clearly related to soil temperature and photosynthetic active radiation, we have not yet identified a parameter that governs variations in methane exchange. Various environmental parameters appear to be related to methane emissions (including soil moisture, soil and air temperature and wind direction), but the scatter with respect to half hourly methane fluxes is too large to be useful for gap modeling. Analysis of daily averages reduces the scatter, but since methane exchange exhibits considerable daily variation, daily averages are not useful to fill data gaps of half hourly fluxes. In consequence, as the daily course is the summary result of all environmental parameters having influence on the methane exchange at the half-hour time scale of the measurements, the ensemble mean diurnal variation method over a suitable number of days is considered the most practical choice of gap filling method for methane fluxes at Schechenfilz site for estimating daily and annual sums. Overall, the annual CO2 uptake is estimated at a magnitude between -50 and -80 g C m-2 a-1, whereas the annual methane emissions are estimated to be about +6 g C m-2 a-1. Since N2O emissions can be neglected at natural peatland sites, the natural bog-pine ecosystem Schechenfilz is indicated to be a weak net sink of greenhouse gases in the past year, even if the higher global warming potential of methane is considered.

The 3000-4000 cal. BP anthropogenic shift in fire regime in the French Pyrenees.

NASA Astrophysics Data System (ADS)

Rius, D.; Vannière, B.; Galop, D.; Richard, H.

2009-04-01

Fire is a key disturbing agent in a wide range of ecosystems: boreal biome (Pitkanen, 2000), Mediterranean area (Colombaroli et al., 2008) as well as temperate European mountain zones (Tinner et al., 1999). During the Holocene, climate may control fire regime by both ignition and fire spread-favouring conditions (i.e. composition, structure and moisture of biomass) whereas man may change charcoal accumulation patterns through type and intensity of agro-pastoral activities. In western and Mediterranean Europe, single sites charcoal analysis recorded the anthropogenic forcing over fire regime broadly between the mid and the late-Holocene. Turner et al (2008) showed that climate and fire had been disconnected since 1700 cal. BP in Turkey. In central Swiss, Mean Fire Interval decreased by two times 2000 years ago due to increasing human impact (Stahli et al., 2006). In Italy, climate and man have had a combined influence on fire-hazard since ca 4000 cal. BP (Vannière et al., 2008). In the Pyrenees Mountains, the linkage between agro-pastoral practices and fire could be dated back to ca 4000-3000 cal. BP with a clear succession of a clearance phase (high fire frequency) followed by a quite linear trend throughout Middle Ages and Modern times corresponding to a change in fire use (Vanniere et al., 2001; Galop et al., 2002, Rius et al., in press). The quantification of fire regimes parameters such as frequency with robust methodological tools (Inferred Fire Frequency, Mean Fire Interval) is needed to understand and characterise such shifts. Here we present two sequences from the Lourdes basin (col d'Ech peat bog) and from the occidental Pyrenees (Gabarn peat bog), which cover the last 9000 years with high temporal resolution. The main goals of this study were to (1) assess control factors of fire regime throughout the lateglacial and Holocene (climate and/or man) on the local scale, (2) evidence the local/regional significance of these control factors , (3) discuss the role of fire in landscape management during the last 3000 years. These fire records emphasizes a shift in fire regime between ca 4000 and 3000 cal BP with similar trends during the last 3000 years (i.e. Mean Fire Interval = 150 years), which appear to be human-driven. However, both Neolithic and Bronze Age periods have different charcoal accumulation patterns suggesting discrepancies between local fire histories and thus different land-use trends and intensity. References Colombaroli D., Vannière B., Chapron E., Magny M. & Tinner W., 2008. Fire-vegetation interactions during the Mesolithic-Neolithic at Lago dell'Accesa, Italy. The Holocene 18: 679-692. Galop, D., Vanniere, B., Fontugne, M., 2002. Human activities and fire history since 4500 BC on the northern slope of the Pyrenees: a record from Cuguron (Central Pyrenees, France). Proceedings of the Second International Meeting of Anthracology, Paris, September 2000, BAR International Series, 43-51. Pitkanen A., 2000. Fire frequency and forest structure at a dry site between Ad 400 and 1110 based on charcoal and pollen records from a laminated lake sediment in eastern Finland. The Holocene 10,2: 221-228. Rius D., Vanniere B. & Galop D., in press. Fire frequency and landscape management in the north-western Pyrenean piedmont (France) since early Neolithic (8000 cal. BP). The Holocene. Stähli, M., Finsinger, W., Tinner, W., Allgower, B., 2006. Wildfire history and fire ecology of the Swiss National Park (Central Alps): new evidence from charcoal, pollen and plant macrofossils. The Holocene 16, 805-817. Tinner, W., Hubschmid, P., Wehrli, M., Ammann, B., Conedera, M., 1999. Long-term forest fire ecology and dynamics in southern Switzerland. Journal of Ecology 87, 273-289. Turner R., Roberts N. & Jones M. D., 2008. Climatic pacing of Mediterranean fire histories from lake sedimentary microcharcoal. Global and Planetary Change 63: 317-324. Vanniere, B., Galop, D., Rendu, C., Davasse, B., 2001. Feu et pratiques agro-pastorales dans les Pyrénées-Orientales : le cas de la montagne d'Enveitg (Cerdagne, Pyrénées-Orientales, France). R.G.P.S.O.,11, 29-42. Vanniere, B., Colombaroli, D., Chapron, E., Leroux, A., Tinner, W., Magny, M., 2008. Climate versus human-driven fire regimes in Mediterranean landscapes : the Holocene record of Lago dell'Accesa (Tuscany, Italy). Quaternary Science Reviews 27, 1181- 1196.

SPRUCE S1 Bog Fine-root Production and Standing Crop Assessed With Minirhizotrons in the Southern and Northern Ends of the S1 Bog

DOE Data Explorer

Iversen, C. M. [Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA; Childs, J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA; Norby, R. J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA; Garrett, A. [Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA; Martin, A. [Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA; Spence, J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA; Ontl, T. A. [Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA

2017-01-01

This data set reports fine-root peak growth and standing crop measurements from a forested, ombrotrophic bog as determined using non-destructive minirhizotron technology. Minirhizotron images were collected throughout the growing seasons of 2011 and 2012 at the southern and northern ends of the S1 bog across gradients of tree density in paired hummock and hollow microtopography. The dominant woody species in the bog, and focus of the investigation, were trees Picea mariana and Larix laricina, and ericaceous shrubs Rhododendron groenlandicum and Chamaedaphne calyculata.

Bryophytes as Climate Indicators: moss and liverwort photosynthetic limitations and carbon isotope signals in organic material and peat deposits

NASA Astrophysics Data System (ADS)

Griffiths, H.; Royles, J.; Horwath, A.; Hodell, D. A.; Convey, P.; Hodgson, D.; Wingate, L.; Ogeé, J.

2011-12-01

Bryophytes make a significant contribution to carbon sequestration and storage in polar, boreal, temperate and tropical biomes, and yet there is limited understanding of the determinants of carbon isotope composition. Bryophytes are poikilohydric and lack stomata in the vegetative (gametophyte) stage, and lack of roots and reliance on liquid water to maintain hydration status also imposes diffusional limitations on CO2 uptake and extent of carbon isotope discrimination. Real-time gas exchange and instantaneous discrimination studies can be used to quantify responses to liquid phase limitation. Thus, wetted tissues show less negative δ13C signals due to liquid phase conductance and, as the thallus surface dries, maximum CO2 assimilation and discrimination are attained when the limitation is primarily the internal (mesophyll) conductance. Continued desiccation then leads to additional biochemical limitation in drought tolerant species, and low discrimination, although the carbon gain is low at this time. In this paper we explore the extent of carbon isotope discrimination in bulk organic material and cellulose as a function of climatic and environmental conditions, in temperate, tropical and Antarctic bryophytes. Field studies have been used to investigate seasonal variations in precipitation and water vapour inputs for cloud forest formations as a function of bryophyte biomass, diversity and isotope composition in epiphytes (particularly leafy liverworts) along an altitudinal gradient in Peru. In the Antarctic, moss banks sampled on Signy Island consisted of only two species, primarily Chorisodontium aciphyllum and some Polytrichum strictum, allowing the collection of shallow and deep cores representative of growth over the past 200 to 2000 years. The well-preserved peat has provided data on growth (14C) and stable isotopic proxies (13C, 18O) for material contemporary with recent anthropogenic climate forcing (over the past 200 years), for comparison with longer-term trends. Once corrected for source CO2 inputs, the carbon isotope signals are consistent with recent increases in growing season length. Laboratory studies on real-time CO2 uptake and isotope discrimination as a function of water content, for the desiccation-tolerant moss Syntrichia ruralis, reveal the interactions between surface water, liquid phase and mesophyll diffusion limitation. These data have been used to develop a model for isotope discrimination in mosses as a function of water status and we will discuss the extent that such a model can be used predictively to determine moss-peat water status, and infer current and past climatic conditions.

Climatic Controls on the Porewater Chemistry of Mid-Continental Wetlands

NASA Astrophysics Data System (ADS)

Levy, Zeno Francis

Wetlands develop where climate and physiography conspire to maintain saturated soils at the land surface, support diverse plant and animal communities, and serve as globally important sinks for atmospheric carbon. The chemistry of wetland porewaters impacts near-surface biological communities and subsurface biogeochemical processes that influence carbon cycling in the environment. Wetland porewater chemistry is a dynamic byproduct of complex hydrogeological processes that cause meteoric waters to enter groundwater systems (recharge) or groundwater to flow to the land surface (discharge). Changes in climate can alter subsurface hydraulic gradients that determine the recharge and discharge functions of wetlands, which in turn control the hydrogeochemical evolution of wetland porewaters. The climate of mid-continental North America is influenced by competing air masses with vastly different temperature and moisture contents originating from the Pacific Coast, the Gulf of Mexico, and the Arctic. The interactions of these air masses result in large dynamic shifts of climate regimes characterized by decadal-scale oscillations between periods of drought and heavy rain. Over the course of the 20th century, a shift occurred towards wetter climate in the mid-continental region. This dissertation examines the impact of this climate shift on the porewater chemistry of two very different wetland systems, located only 350 km apart: the Glacial Lake Agassiz Peatlands (GLAP) of northern Minnesota and the Cottonwood Lake Study Area (CLSA) of North Dakota. The former study site consists of a large (7,600 km2), circumboreal peatland that developed an extensive blanket of peat over the last 5000 years on a relatively flat glacial lake bed within a sub-humid to semi-arid climate gradient characterized by small annual atmospheric moisture surpluses and frequent droughts. The latter study site consists of a 0.92 km2 complex of small (meter-scale) "prairie pothole" wetlands located on a hummocky glacial stagnation moraine under semi-arid climate where wetlands frequently fill and dry with surface ponds over low-permeability glacial till in response to snowmelt runoff and evapotranspiration. Both sites have been the subject of long-term hydrological study since c. 1980 and are well-established examples of the sensitivity of wetland functions to changes in climate. The first chapter of this dissertation utilizes a semi-conservative tracer suite (pH, Ca, Mg, Sr, 87Sr/86Sr) to fingerprint discharge of calcareous groundwater to GLAP peat along a 6 km transect from a bog crest downslope to an internal fen water track and bog islands. However, stable isotopes of the peat porewaters (delta18O and delta 2H) show that the subsurface throughout the entire study area is currently flushed with recharge from the near surface peat. I hypothesize that back-diffusion of groundwater-derived solutes from the peat matrix to active pore-spaces has allowed the geochemical signal from paleo-hydrogeologic discharge to persist into the current regime of dilute recharge. This effect promotes methane generation in the peatland subsurface by allowing transport of labile carbon compounds from the land surface to depth while maintaining geochemical conditions (i.e. pH) in the deep peat favorable to biogenic methane production. The results of this study show that autogenic hydrogeochemical feedback mechanisms contribute to the resilience of peatlands systems and associated ecological functions against climate change. The second chapter of this dissertation consists of a detailed geoelectrical survey of a well-studied, closed-basin prairie wetland (P1) in the CLSA that has experienced record drought and heavy rains (i.e. deluge) during the late 20th century. Subsurface storage of sulfate (SO4) salts allows many such closed-basin prairie wetlands to maintain moderate surface water salinities (TDS from 1 to 10 g L-1) that influence communities of aquatic biota. I imaged saline lenses of sulfate-rich porewater (TDS > 10 g L-1) in wetland sediments beneath the bathymetric low of the wetland and within the currently ponded area along the shoreline of a prior pond stand. Analyses of long-term (1979-2014) groundwater and surface water levels in the wetland suggest that the saline lenses formed during paleo-droughts when the groundwater levels dropped below the wetland bed and are stable in the subsurface on at least centennial timescales. I hypothesize a "drought-induced recharge" mechanism by which wetlands maintain moderate surface water salinity by subsurface storage during droughts when the wetlands dry and intermittent runoff events flush surface salts down secondary porosity created by desiccation fractures and terrestrial plant roots. Drought-derived saline groundwater has the potential to increase wetland salinity during record wet climate conditions currently prevalent in the Prairie Pothole Region. The third chapter of this dissertation extends the findings of the second chapter by a detailed geochemical survey of wetland porewater, pond water, and upland groundwater in the P1 basin. (Abstract shortened by ProQuest.).

A synthesis of growing-season, non-growing season, and annual methane emission measurements among temperate, boreal, and tundra wetlands and uplands

NASA Astrophysics Data System (ADS)

Treat, C. C.; Bloom, A. A.; Marushchak, M. E.

2017-12-01

Wetlands are the largest natural source of methane to the atmosphere, while upland soils are a consistent sink of atmospheric methane. Wetland methane emissions are highly variable among sites, years, and temporal scales due to differences in production, oxidation, and transport pathways. Currently, process model predictions of methane emissions from wetlands remain challenging due to uncertain parameterizations of net methane production and emission processes. Here, we synthesize growing season, non-growing season, and annual methane emissions from chamber and eddy-covariance measurements for more than 150 sites in undisturbed temperate, boreal, and tundra wetlands and uplands. We compare the magnitude of fluxes among regions, wetland classifications, vegetation classifications, and environmental variables. Growing season measurements were most abundant in bogs, fens, and tundra sites, while marshes and swamps were relatively undersampled. Annual methane emissions were largest from marshes and lowest from upland mineral soils. Non-growing season emissions accounted for large fraction of annual methane emissions, especially in tundra sites. These results provide constraints for methane emissions from temporal, boreal, and arctic wetlands utilizing the numerous flux measurements conducted over the past 25 years. We find that state-of-the-art model ensembles are seasonally biased; in particular, the vast majority of models overestimate predictions of the growing season to annual wetland methane emission ratio across all biomes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hornibrook, E.R.C.; Longstaffe, F.J.; Fyfe, W.S.

The identity and distribution of substrates that support CH{sub 4} production in wetlands is poorly known at present. Organic compounds are the primary methanogenic precursor at all depths within anoxic wetland soils; however, the distribution of microbial processes by which these compounds are ultimately converted to CH{sub 4} is uncertain. Based on stable isotope measurements of CH{sub 4} and {Sigma}CO{sub 2} extracted from soil porewaters in two temperate zone wetlands, we present evidence that a systematic spatial distribution of microbial methanogenic pathways can exist in certain anoxic, organic-rich soils. CH{sub 4} production by the acetate fermentation pathway is favored inmore » the shallow subsurface. while methanogenesis from the reduction of CO{sub 2} with H{sub 2} becomes more predominant in older, less reactive peat at depth. This distribution can account for many of the reported CH{sub 4} emission characteristics of wetlands, in particular, their sensitivity to changes in primary productivity, temperature, and hydrology. These factors play an important role in controlling the short-term supply of labile substrates to fermentive methanogens in the shallow subsurface where the most intense CH{sub 4} production occurs. Predominance of the CO{sub 2}-reduction pathway at depth may help to explain reports of CH{sub 4} with a semifossil age in lower peat layers. 60 refs., 7 figs., 1 tab.« less

Recent rates of carbon accumulation in montane fens ofYosemite National Park, California, U.S.A.

USGS Publications Warehouse

Drexler, Judith; Fuller, Christopher C.; Orlando, James L.; Moore, Peggy E.

2016-01-01

Little is known about recent rates of carbon storage in montane peatlands, particularly in the western United States. Here we report on recent rates of carbon accumulation (past 50 to 100 years) in montane groundwater-fed peatlands (fens) of Yosemite National Park in central California, U.S.A. Peat cores were collected at three sites ranging in elevation from 2070 to 2500 m. Core sections were analyzed for bulk density, % organic carbon, and 210Pb activities for dating purposes. Organic carbon densities ranged from 0.026 to 0.065 g C cm-3. Mean vertical accretion rates estimated using210Pb over the 50-year period from ∼1960 to 2011 and the 100-year period from ∼1910 to 2011 were 0.28 (standard deviation = ±0.09) and 0.18 (±-0.04) cm yr-1, respectively. Mean carbon accumulation rates over the 50- and 100-year periods were 95.4 (±25.4) and 74.7 (±17.2) g C m-2 yr-1, respectively. Such rates are similar to recent rates of carbon accumulation in rich fens in western Canada, but more studies are needed to definitively establish both the similarities and differences in peat formation between boreal and temperate montane fens.

Investigating Bogs: An Interdisciplinary Adventure.

ERIC Educational Resources Information Center

Pankiewicz, Philip R.; Schneider, Lois

1995-01-01

Presents the case for the use of bogs as ideal sites for hundreds of interdisciplinary lessons that combine chemistry, geology, various branches of biology, and wetlands archaeology. Includes general guidelines to aid in the design of interdisciplinary bog studies. (DDR)

Vulnerability of North American Boreal Peatlands to Interactions between Climate, Hydrology, and Wildland Fires

NASA Astrophysics Data System (ADS)

Bourgeau-Chavez, L. L.; Jenkins, L. K.; Kasischke, E. S.; Turetsky, M.; Benscoter, B.; Banda, E. J.; Boren, E. J.; Endres, S. L.; Billmire, M.

2013-12-01

North American boreal peatland sites of Alaska, Alberta Canada, and the southern limit of the boreal ecoregion (Michigan's Upper Peninsula) are the focus of an ongoing project to better understand the fire weather, hydrology, and climatic controls on boreal peatland fires. The overall goal of the research project is to reduce uncertainties of the role of northern high latitude ecosystems in the global carbon cycle and to improve carbon emission estimates from boreal fires. Boreal peatlands store tremendous reservoirs of soil carbon that are likely to become increasingly vulnerable to fire as climate change lowers water tables and exposes C-rich peat to burning. Increasing fire activity in peatlands could cause these ecosystems to become net sources of C to the atmosphere, which is likely to have large influences on atmospheric carbon concentrations through positive feedbacks that enhance climate warming. Remote sensing is key to monitoring, understanding and quantifying changes occurring in boreal peatlands. Remote sensing methods are being developed to: 1) map and classify peatland cover types; 2) characterize seasonal and inter-annual variations in the moisture content of surface peat (fuel) layers; 3) map the extent and seasonal timing of fires in peatlands; and 4) discriminate different levels of fuel consumption/burn severity in peat fires. A hybrid radar and optical infrared methodology has been developed to map peatland types (bog vs. fen) and level of biomass (open herbaceous, shrubby, forested). This methodology relies on multi-season data to detect phenological changes in hydrology which characterize the different ecosystem types. Landsat data are being used to discriminate burn severity classes in the peatland types using standard dNBR methods as well as individual bands. Cross referencing the peatland maps and burn severity maps will allow for assessment of the distribution of upland and peatland ecosystems affected by fire and quantitative analysis of emissions. Radar imagery from multiple platforms (L-band PALSAR, C-band ERS-2, Envisat, and Radarsat-2) is being used to develop soil moisture extraction algorithms to monitor changes (drying - wetting) through time and to develop a standard method for soil moisture assessment. Using data from the 1990s (ERS-1 and 2) through the present (Radarsat-2) will allow for determination of patterns of wetting and drying across the landscape. All the remote sensing analysis is supported with field work which has been coordinated with that of Canadian scientists. Field collection includes vegetation and hydrology data to validate peatland distribution maps, collection of water table depths and peat moisture content data to aid in algorithm development for radar organic soil moisture retrieval, and characterization of variations in depth of burning and carbon consumption during peatland fires to use in burn severity mapping and fire emissions modeling.

Impact of raized bogs on export of carbon and river water chemical composition in Western Siberia

NASA Astrophysics Data System (ADS)

Voistinova, Elena

2010-05-01

Bogs play an important role in functioning of the biosphere. Specific geochemical environment of the bogs results in formation of the special biogeochemical cycle of the elements. Processes of decay and transformation of organic material define the reductive conditions of bog water, form and migratory mobility of the chemical elements. Particular interest in recent years is aroused by the question of content and dynamics of the carbon in bog and river water according to indicated natural and climatic changes on the territory. The most important parts of the carbon balance in bog ecosystems together with processes of exhalation from deposit surface in the form of CO2 is its export with river water. The results of research carried out in scientific station "Vasyugansky" in south taiga subzone of Western Siberia showed that chemical composition of raised bog water includes high amounts of total iron (2,13 mg/l), ammonium ions (5,33 mg/l), humic and fulvic acids (5,21 mg/l and 45,8 mg/l), dissolved organic carbon (69,1 mg/l), COD (236,93 mgO/l), there are low mineralization and indicators of pH. Carbon comes in bog water in organic compounds: carboxylic acids, phenols, aromatic and paraffin hydrocarbons, organic phosphates, phthalates and other compounds. Formation of river waters composition in the Western Siberia takes place in the following context: high level of bogged river catchments (sometimes up to 70%), excess humidification and low heat provision. Basing on the results of study of hydrochemical runoff in small and medium rivers with different levels of bogged in river catchments (Chaya, Bakchar, Klyuch, Gavrilovka) it was noted that raised bog influence on river waters chemical composition shows in ion runoff decrease, organic substances runoff increase, increase of amounts of total iron, ammonium irons and water pH indicators decrease. Study of humic matters migration is very important in the context of formation of flexible complexes of humic and fulvic acids and heavy metals, which should be taken into account when in waterlogged regions constructing large industrial projects and in formation of water removing.

Atmospheric metal pollution records in the Kovářská Bog (Czech Republic) as an indicator of anthropogenic activities over the last three millennia.

PubMed

Bohdálková, Leona; Bohdálek, Petr; Břízová, Eva; Pacherová, Petra; Kuběna, Aleš Antonín

2018-08-15

Three peat cores were extracted from the Kovářská Bog in the central Ore Mountains to study anthropogenic pollution generated by mining and metallurgy. The core profiles were 14 C dated, and concentrations of selected elements were determined by ICP MS and HG-AAS. Principal component analysis indicated that Pb, Cu, As and Ag may be useful elements for the reconstruction of historical atmospheric pollution. Total and anthropogenic accumulation rates (ARs) of Pb, Cu and As estimated for the last ca. 3500years showed similar chronologies, and revealed twelve periods of elevated ARs of Pb, As and Cu related to possible mining and metallurgic activities. In total, four periods of elevated ARs of Pb, Cu and As were detected during the Middle and Late Bronze Ages, including a distinct Late Bronze Age pollution event between 1030BCE and 910BCE. The Iron Age included three episodes of increased ARs of Pb and As; the first and the most distinctive episode, recorded between 730 and 440BCE, was simultaneous with the Bylany culture during the Hallstatt Period. The Roman Age was characterized by one pollution event, two events were detected in the Middle Ages, and the last two during the modern period. Enhanced element ARs in the late 12th and 15th centuries clearly documented the onset of two periods of intense mining in the Ore Mountains. Metal ARs culminated in ca. 1600CE, and subsequently decreased after the beginning of the Thirty Years' War. The last boom of mining between 1700CE and 1830CE represented the last period of important metallurgical operations. Late Medieval and modern period metal ARs are in good agreement with written documents. Earlier pollution peaks suggest that local metal production could have a much longer tradition than commonly believed; however, archaeological or written evidence is scarce or lacking. Copyright © 2018 Elsevier B.V. All rights reserved.

Sphagnum Mosses - Masters of Efficient N-Uptake while Avoiding Intoxication

PubMed Central

Fritz, Christian; Lamers, Leon P. M.; Riaz, Muhammad; van den Berg, Leon J. L.; Elzenga, Theo J. T. M.

2014-01-01

Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant competition, and carbon sequestration in Sphagnum peatlands. The interacting effects of rain N concentration and exposure time on moss N-uptake rates are, however, poorly understood. We investigated the effects of N-concentration (1, 5, 10, 50, 100, 500 µM), N-form (15N - ammonium or nitrate) and exposure time (0.5, 2, 72 h) on uptake kinetics for Sphagnum magellanicum from a pristine bog in Patagonia (Argentina) and from a Dutch bog exposed to decades of N-pollution. Uptake rates for ammonium were higher than for nitrate, and N-binding at adsorption sites was negligible. During the first 0.5 h, N-uptake followed saturation kinetics revealing a high affinity (Km 3.5–6.5 µM). Ammonium was taken up 8 times faster than nitrate, whereas over 72 hours this was only 2 times. Uptake rates decreased drastically with increasing exposure times, which implies that many short-term N-uptake experiments in literature may well have overestimated long-term uptake rates and ecosystem retention. Sphagnum from the polluted site (i.e. long-term N exposure) showed lower uptake rates than mosses from the pristine site, indicating an adaptive response. Sphagnum therefore appears to be highly efficient in using short N pulses (e.g. rainfall in pristine areas). This strategy has important ecological and evolutionary implications: at high N input rates, the risk of N-toxicity seems to be reduced by lower uptake rates of Sphagnum, at the expense of its long-term filter capacity and related competitive advantage over vascular plants. As shown by our conceptual model, interacting effects of N-deposition and climate change (changes in rainfall) will seriously alter the functioning of Sphagnum peatlands. PMID:24416125

Earth Observations taken by the Expedition 15 Crew

NASA Image and Video Library

2007-05-11

ISS015-E-07649 (11 May 2007) --- Saskatchewan River Delta, Manitoba, Canada is featured in this image photographed by an Expedition 15 crewmember on the International Space Station. This image highlights a portion of the Saskatchewan River delta extending into Cedar Lake in the Province of Manitoba. The Saskatchewan River watershed extends from the Rocky Mountains of Alberta through the plains of Saskatchewan and Manitoba. The construction of the Grand Rapids Dam to the southeast (not shown) in the 1960s flooded the Cedar Lake basin. This has resulted in the formation of numerous shallow, muddy lakes and bogs (dark green to dark grey irregular areas and at upper right) in and around the Saskatchewan River delta. The level of saturation in these bogs is such that peat (semiconsolidated plant and organic matter) deposits have formed; over long periods of time and under the right geological conditions, such deposits can become coal. The velocity of Saskatchewan River water slows significantly as it enters Cedar Lake; as the flow velocity drops, entrained sediment comprised of silt, clay, sand, and gravel is deposited at the river mouth. These deposits, called alluvium by geologists, account for much of the light tan to grey materials bordering the active channels visible in the image (Saskatchewan River, Summerberry River). According to scientists, fossil-bearing amber -- originating from Late Cretaceous (approximately 65-99 million years ago) coal deposits over a thousand kilometers to the west of Cedar Lake -- is also found in the deltaic sediments. As the deposits accumulate, old channels are abandoned and new channels are formed, as the river seeks more favorable flow paths into the lake, this process (known as avulsion) builds out the river delta over time. A typical "birds foot" delta form is currently being constructed at the mouth of the Saskatchewan River (lower left). The birds foot structure is approximately 13 kilometers wide. The Mississippi River's active delta, while having the same general form, is much larger by comparison -- it is approximately 50 kilometers wide.

Sphagnum mosses--masters of efficient N-uptake while avoiding intoxication.

PubMed

Fritz, Christian; Lamers, Leon P M; Riaz, Muhammad; van den Berg, Leon J L; Elzenga, Theo J T M

2014-01-01

Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant competition, and carbon sequestration in Sphagnum peatlands. The interacting effects of rain N concentration and exposure time on moss N-uptake rates are, however, poorly understood. We investigated the effects of N-concentration (1, 5, 10, 50, 100, 500 µM), N-form ((15)N-ammonium or nitrate) and exposure time (0.5, 2, 72 h) on uptake kinetics for Sphagnum magellanicum from a pristine bog in Patagonia (Argentina) and from a Dutch bog exposed to decades of N-pollution. Uptake rates for ammonium were higher than for nitrate, and N-binding at adsorption sites was negligible. During the first 0.5 h, N-uptake followed saturation kinetics revealing a high affinity (Km 3.5-6.5 µM). Ammonium was taken up 8 times faster than nitrate, whereas over 72 hours this was only 2 times. Uptake rates decreased drastically with increasing exposure times, which implies that many short-term N-uptake experiments in literature may well have overestimated long-term uptake rates and ecosystem retention. Sphagnum from the polluted site (i.e. long-term N exposure) showed lower uptake rates than mosses from the pristine site, indicating an adaptive response. Sphagnum therefore appears to be highly efficient in using short N pulses (e.g. rainfall in pristine areas). This strategy has important ecological and evolutionary implications: at high N input rates, the risk of N-toxicity seems to be reduced by lower uptake rates of Sphagnum, at the expense of its long-term filter capacity and related competitive advantage over vascular plants. As shown by our conceptual model, interacting effects of N-deposition and climate change (changes in rainfall) will seriously alter the functioning of Sphagnum peatlands.

Changes in dissolved organic matter quality in a peatland and forest headwater stream as a function of seasonality and hydrologic conditions

NASA Astrophysics Data System (ADS)

Broder, Tanja; Knorr, Klaus-Holger; Biester, Harald

2017-04-01

Peatlands and peaty riparian zones are major sources of dissolved organic matter (DOM), but are poorly understood in terms of export dynamics and controls thereof. Thereby quality of DOM affects function and behavior of DOM in aquatic ecosystems, but DOM quality can also help to track DOM sources and their export dynamics under specific hydrologic preconditions. The objective of this study was to elucidate controls on temporal variability in DOM concentration and quality in stream water draining a bog and a forested peaty riparian zone, particularly considering drought and storm flow events. DOM quality was monitored using spectrofluorometric indices for aromaticity (SUVA254), apparent molecular size (SR) and precursor organic material (FI), as well as PARAFAC modeling of excitation emission matrices (EEMs). Indices for DOM quality exhibited major changes due to different hydrologic conditions, but patterns were also dependent on season. Stream water at the forested site with mineral, peaty soils generally exhibited higher variability in DOM concentrations and quality compared to the outflow of an ombrotrophic bog, where DOM was less susceptible to changes in hydrologic conditions. During snowmelt and spring events, near-surface protein-like DOM pools were exported. A microbial DOM fraction originating from groundwater and deep peat layers was increasing during drought, while a strongly microbially altered DOM fraction was also exported by discharge events with dry preconditions at the forested site. This might be due to accelerated microbial activity in the peaty riparian zone of the forested site under these preconditions. Our study demonstrated that DOM export dynamics are not only a passive mixing of different hydrological sources, but monitoring studies have to consider that DOM quality depends on hydrologic preconditions and season. Moreover, the forested peaty riparian zone generated the most variability in headwater DOM quantity and quality, as could be tracked by the used spectrofluorometric indices.

Methane fluxes from a wet puna ecosystem in the Peruvian Andes

NASA Astrophysics Data System (ADS)

Jones, Sam; Diem, Torsten; Priscila Huaraca Quispe, Lidia; Quispe Ccahuana, Adan Julian; Meir, Patrick; Arn Teh, Yit

2014-05-01

Discrepancies exist between top-down and bottom-up estimates of the tropical South American atmospheric methane budget. This suggests that current source-sink inventories fail to adequately characterise the landscapes of the region. This may be particularly true of Andean environments where very few field observations have been made. The high tropical Andes, between tree and permanent snow-lines, is home to diverse grass, shrub and giant rosette dominated ecosystems known variously from Venezuela to northern Chile and Argentina as paramo, jalca and puna. In humid regions these are characterised by wet, organic-rich mineral soils, peat-forming wetlands and shallow lakes. Such conditions are likely to promote methane production and potentially represent a regionally significant source to the atmosphere that should be considered. We report on methane fluxes from a bunch-grass dominated puna habitat at 3500 m above sea level in south-eastern Peru. Mean annual temperature and precipitation are 11 °C and 2500 mm, respectively. Temperature is aseasonal but experiences considerable diurnal variations with overnight frosting common-place. In contrast, rainfall is intensely episodic and has a pronounced wet season between September and March. Sampling encompassed a range of topographic features, such as grassland on freely draining, gently inclined or steep slopes and depressions containing bogs, over a 3 ha ridge to basin transition. Monthly sampling was carried out between January 2011 and June 2013 to investigate seasonal variability in methane fluxes. Intensive sampling campaigns were conducted to investigate spatial and short-term variations on a daily basis in two nine-day campaigns during wet and dry season. The site was a net source of methane to the atmosphere during the period of study. Methane fluxes were dominated by emissions from bogs, whereas, freely draining grassland exhibited weak source or marginal sink activity. Temporal variations were most notable at the seasonal scale with fluxes during the wet season almost an order of magnitude greater than those of the dry season. Mean emissions from bogs during wet and dry season were 85.0 (15.0) and 10.0 (2.0) mg C-CH4 m-2 d-1, respectively. Similarly, mean fluxes in the grassland were 0.4 (0.7) and -0.05 (0.6) mg C-CH4 m-2 d-1. These data highlight the importance of considering such Andean highlands in landscape scale source-sink inventories. In this respect, understanding the influence of differences in climatic regime found across the Andes and determining the areal extent of topographic hotspots driving methane emissions within these environments are key challenges.

Latitude and pH driven trends in the molecular composition of DOM across a north south transect along the Yenisei River

NASA Astrophysics Data System (ADS)

Roth, Vanessa-Nina; Dittmar, Thorsten; Gaupp, Reinhard; Gleixner, Gerd

2013-12-01

We used electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) to identify the molecular composition of dissolved organic matter (DOM) collected from different ecosystems along a transect crossing Siberia’s northern and middle Taiga. This information is urgently needed to help elucidate global carbon cycling and export through Russian rivers. In total, we analyzed DOM samples from eleven Yenisei tributaries and seven bogs. Freeze-dried and re-dissolved DOM was desalted via solid phase extraction (SPE) and eluted in methanol for ESI-FT-ICR-MS measurements. We recorded 15209 different masses and identified 7382 molecular formulae in the mass range between m/z = 150 and 800. We utilized the relative FT-ICR-MS signal intensities of 3384 molecular formulae above a conservatively set limit of detection and summarized the molecular characteristics for each measurement using ten magnitude-weighted parameters ((O/C)w, (H/C)w, (N/C)w, (DBE)w, (DBE/C)w, (DBE/O)w, (DBE-O)w, (C#)w, (MW)w and (AI)w) for redundancy analysis. Consequently, we revealed that the molecular composition of DOM depends mainly on pH and geographical latitude. After applying variation partitioning to the peak data, we isolated molecular formulae that were strongly positive or negatively correlated with latitude and pH. We used the chemical information from 13 parameters (C#, H#, N#, O#, O/C, H/C, DBE, DBE/C, DBE/O, AI, N/C, DBE-O and MW) to characterize the extracted molecular formulae. Using latitude along the gradient representing climatic variation, we found a higher abundance of smaller molecules, nitrogen-containing compounds and unsaturated Cdbnd C functionalities at higher latitudes. As possible reasons for the different molecular characteristics occurring along this gradient, we suggested that the decomposition was temperature dependent resulting to a higher abundance of non-degraded lignin-derived phenolic substances. We demonstrated that bog samples, which were differentiated from river samples by their lower pH values, distinguish themselves by their higher unsaturation and molecular size. These molecular characteristics might suggest less phenol oxidase degradation occurs alongside a higher abundance of phenolic substances in bogs due to low pH and anoxic conditions. We concluded that heating at the higher latitudes will increase decomposition and feedback on the nitrogen cycle due to the increased mineralization of organic nitrogen compounds, although the peat system will be less affected due to pH inhibition.

The sustainable management of ameliorated peatlands on changed land use conditions; scenarios of constrains and possibilities

NASA Astrophysics Data System (ADS)

Shanskiy, , Merrit; Vollmer, Elis; Penu, Priit

2015-04-01

The utilization of organic soils for forestry or agriculture requires the land amelioration that could result on the peat losses from 15 to 20 t ha-1 in a year on following five years. After five years, the peat losses will be 5 - 15 t ha-1 in a year. The agricultural land resource on different types of organic soils (including ameliorated bogs) in Estonia is 360 000 ha that comprises 41% of total agricultural land area. The landscape iself is a valuable resource that considered to be a set of characteristics that satisfy needs of people using the landscape: economical or non-economical value; ecological, social, recreational, aesthetical, educational, scientific or even protective value. More diverse landscapes have higher biodiversity and yield more services to public, they are also seen as more sustainable and resilient to short-term changes. In order to maintain landscape diversity, sustainable maintenance is important. The purpose of current study was to estimate the land use potential on three different ameliorated peat areas and to develop the methodology for the futher sustainable utilization in order to secure the best ecological functioning of soil while taking into account maintaining and increasing landscape value. Therefore, site specific soil sampling (n=77) was carried out on predetermined eight study sites. Soil samples were analyzed for main agrochemical parameters (n=17; pHKCl, P, K, C%, N%, S%, ash, main anions and cations). This enables determing site-specific best suitable crops and land use scenarios. For the land resource description (soils type, topology) the digital soil map (1: 10,000) and field sudy based database were used for describing the model areas. For more specific identification of the field layers the Agricultural Registers and Information Board (ARIB) and databases of the Common Agricultural Policy (CAP) payments were used for subsidy schemes chekout. Estonian Nature Information System map tool was used to specify the restrictions on study sites by nature conversation on the maps data about nature protected objects and buffer zones or forming restricted areas around those objects. The results will indicate the utilization possibility and most sustainable scenarios for different land use cases. Moreover, the possible changes in soil functioning accordingly to site specific soil conditions will be discussed and presented.

Methane Emissions from Semi-natural, Drained and Re-wetted Peatlands in Germany

NASA Astrophysics Data System (ADS)

Tiemeyer, B.; Bechtold, M.; Albiac Borraz, E.; Augustin, J.; Drösler, M.; Beetz, S.; Beyer, C.; Eickenscheidt, T.; Fiedler, S.; Förster, C.; Giebels, M.; Glatzel, S.; Heinichen, J.; Höper, H.; Leiber-Sauheitl, K.; Peichl-Brak, M.; Rosskopf, N.; Sommer, M.; Zeitz, J.; Freibauer, A.

2014-12-01

Drained peatlands contribute around 5% to the total German greenhouse gas emissions. While these areas are hotspots for carbon dioxide (CO2) and nitrous oxide (N2O) emissions, some re-wetted peatlands may emit large amounts of methane (CH4). To quantify the GHG emission reductions achieved by the re-wetting of peatlands, the reduced CO2 emissions and the potential CH4fluxes need to be balanced. We synthesized methane flux data from 14 peatlands with 122 sites. At each site, methane fluxes were measured for one to three years with static chambers. The sites comprise arable land, intensive and extensive grassland, forest and peat mining areas as well as semi-natural and re-wetted peatlands on both bog peat, fen peat and other soils rich in organic carbon. Besides the groundwater table we consider further potential drivers for the CH4fluxes such as soil properties (carbon, nitrogen, pH, and physical properties), climatic parameters, land use, and vegetation composition. Annual methane fluxes ranged from low uptake rates (around -1 g CH4-C m² a-1) to very high emissions (> 200 g CH4-C m² a-1). Intensively drained sites showed very low emissions, while for annual mean water levels higher than 5-10 cm below ground, elevated emissions of more than 20 g CH4-C may occur. At some re-wetted sites CH4 emissions of more than 100 g CH4-C m² a-1 were measured, which roughly equal the Global Warming Potential of the CO2-emissions from intensively drained agricultural sites. These high fluxes were probably caused by a combination of nutrient-rich conditions, the dieback of poorly adapted plants and a fast accumulation of organic sediments. However, this was the exception and not the rule even for very wet re-wetted sites. Achieving a model efficiency of 0.72 during cross-validation, a boosted regression tree (BRT) model was well able to describe logarithmic CH4-fluxes. Groundwater level, biotope type, soil nitrogen content, and ponding duration during summer were the most important controls. Combining the BRT model with soil, land use, and groundwater table maps as well as weather data, methane fluxes were upscaled for Germany.

Two high resolution terrestrial records of atmospheric Pb deposition from New Brunswick, Canada, and Loch Laxford, Scotland.

PubMed

Kylander, Malin E; Weiss, Domink J; Kober, Bernd

2009-02-15

Environmental archives like peat deposits allow for the reconstruction of both naturally and anthropogenically forced changes in the biogeochemical cycle of Pb as well as the quantification of past and present atmospheric Pb pollution. However, records of atmospheric Pb deposition from pre-industrial times are lacking. In a publication by Weiss et al. [Weiss, D., Shotyk, W., Boyle, E.A., Kramers, J.D., Appleby, P.G., Cheburkin, A.K., Comparative study of the temporal evolution of atmospheric lead deposition in Scotland and eastern Canada using blanket peat bogs. Sci Total Environ 2002;292:7-18]. Pb isotopes data measured by Q-ICP-MS and TIMS, concentration and enrichment data was presented for sites in eastern Canada (PeW1) and northwestern Scotland (LL7c), dating to 1586 A.D and 715 A.D., respectively. Here these same cores are re-analysed for Pb isotopes by MC-ICP-MS thereby acquiring 204Pb data and improving on the original data in terms of resolution and temporal coverage. Significant differences were found between the Q-ICP-MS/TIMS and MC-ICP-MS measurements, particularly at PeW1. These discrepancies are attributed to the problematic presence of organic matter during sample preparation and analysis complicated by the heterogeneity of the organic compounds that survived sample preparation steps. The precision and accuracy of Pb isotopes in complex matrices like peat is not always well estimated by industrial standards like NIST-SRM 981 Pb. Lead pollution histories at each site were constructed using the MC-ICP-MS data. The entire LL7c record is likely subject to anthropogenic additions. Contributions from local mining were detected in Medieval times. Later, coal use and mining in Scotland, Wales and England became important. After industrialization (ca. 1885 A.D.) contributions from Broken Hill type ores and hence, leaded petrol, dominate atmospheric Pb signatures right up to modern times. At PeW1 anthropogenic impacts are first distinguishable in the late 17th century with the mining and use of local coal. After industrialization (ca. 1810 A.D.), coal and petrol are the main Pb sources. A comprehensive estimate of the natural atmospheric background 206Pb/207Pb signature in eastern Canadian aerosols is made with a value of approximately 1.19.

SPRUCE S1 Bog and SPRUCE Experiment Location Survey Results, 2015

DOE Data Explorer

Griffiths, Natalie A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hook, L. A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hanson, P. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.

2016-01-01

This data set provides a record of the horizontal and vertical survey results of SPRUCE experimental infrastructure and measurement locations on the S1-Bog on the Marcell Experimental Forest and the SPRUCE experimental site within the S1-Bog.

Bog iron formation in the Nassawango Creek watershed, Maryland, USA

USGS Publications Warehouse

Bricker, O.P.; Newell, Wayne L.; Simon, N.S.; ,

2004-01-01

The Nassawango bog ores in the modern environment for surficial geochemical processes were studied. The formation of Nassawango bog ores was suggested to be due to inorganic oxidation when groundwater rich in ferrous iron emerges into the oxic, surficial environment. It was suggested that the process, providing a phosphorus sink, may be an unrecognized benefit for mitigating nutrient loading from agricultural lands. It is found that without the effect of iron fixing bacteria, bog deposites could not form at significant rates.

Paired charcoal and tree-ring records of high-frequency Holocene fire from two New Mexico bog sites

USGS Publications Warehouse

Allen, Craig D.; Anderson, R. Scott; Jass, R.B.; Toney, J.L.; Baisan, C.H.

2008-01-01

Two primary methods for reconstructing paleofire occurrence include dendrochronological dating of fire scars and stand ages from live or dead trees (extending back centuries into the past) and sedimentary records of charcoal particles from lakes and bogs, providing perspectives on fire history that can extend back for many thousands of years. Studies using both proxies have become more common in regions where lakes are present and fire frequencies are low, but are rare where high-frequency surface fires dominate and sedimentary deposits are primarily bogs and wetlands. Here we investigate sedimentary and fire-scar records of fire in two small watersheds in northern New Mexico, in settings recently characterised by relatively high-frequency fire where bogs and wetlands (Chihuahuen??os Bog and Alamo Bog) are more common than lakes. Our research demonstrates that: (1) essential features of the sedimentary charcoal record can be reproduced between multiple cores within a bog deposit; (2) evidence from both fire-scarred trees and charcoal deposits documents an anomalous lack of fire since ???1900, compared with the remainder of the Holocene; (3) sedimentary charcoal records probably underestimate the recurrence of fire events at these high-frequency fire sites; and (4) the sedimentary records from these bogs are complicated by factors such as burning and oxidation of these organic deposits, diversity of vegetation patterns within watersheds, and potential bioturbation by ungulates. We consider a suite of particular challenges in developing and interpreting fire histories from bog and wetland settings in the Southwest. The identification of these issues and constraints with interpretation of sedimentary charcoal fire records does not diminish their essential utility in assessing millennial-scale patterns of fire activity in this dry part of North America. ?? IAWF 2008.

Functional diversity, succession, and human-mediated disturbances in raised bog vegetation.

PubMed

Dyderski, Marcin K; Czapiewska, Natalia; Zajdler, Mateusz; Tyborski, Jarosław; Jagodziński, Andrzej M

2016-08-15

Raised and transitional bogs are one of the most threatened types of ecosystem, due to high specialisation of biota, associated with adaptations to severe environmental conditions. The aim of the study was to characterize the relationships between functional diversity (reflecting ecosystem-shaping processes) of raised bog plant communities and successional gradients (expressed as tree dimensions) and to show how impacts of former clear cuts may alter these relationships in two raised bogs in 'Bory Tucholskie' National Park (N Poland). Herbaceous layers of the plant communities were examined by floristic relevés (25m(2)) on systematically established transects. We also assessed patterns of tree ring widths. There were no relationships between vegetation functional diversity components and successional progress: only functional dispersion was negatively, but weakly, correlated with median DBH. Lack of these relationships may be connected with lack of prevalence of habitat filtering and low level of competition over all the successional phases. Former clear cuts, indicated by peaks of tree ring width, influenced the growth of trees in the bogs studied. In the bog with more intensive clear cuts we found more species with higher trophic requirements, which may indicate nutrient influx. However, we did not observe differences in vegetation patterns, functional traits or functional diversity indices between the two bogs studied. We also did not find an influence of clear cut intensity on relationships between functional diversity indices and successional progress. Thus, we found that alteration of the ecosystems studied by neighbourhood clear cuts did not affect the bogs strongly, as the vegetation was resilient to these impacts. Knowledge of vegetation resilience after clear cuts may be crucial for conservation planning in raised bog ecosystems. Copyright © 2016 Elsevier B.V. All rights reserved.

SPRUCE S1 Bog Porewater, Groundwater, and Stream Chemistry Data: 2011-2013

DOE Data Explorer

Griffiths, N. A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Sebestyen, S. D. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.

2016-01-01

This data set reports the chemistry of S1 Bog porewater, outlet stream water, and groundwater from upland wells from 2011 through 2013. These data provide information for studies of the biogeochemical status of the bog and surrounding groundwater aquifer.