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Sample records for alaska peatland experiment

  1. Nitrogen Inputs and Transformations in a Boreal Wetland: Hypotheses and Preliminary Results From the Alaska Peatland Experiment (APEX)

    NASA Astrophysics Data System (ADS)

    Millar, N.; O'Donnell, J. A.; Turetsky, M. R.

    2005-12-01

    High latitudes are expected to experience some of the most dramatic effects of climate change in the near future. This is already evident from existing permafrost and air temperature records in Alaska. Peatlands are a major component of boreal landscapes and store massive reservoirs of soil organic carbon (C) and nitrogen (N), yet the vulnerability of these organic matter stocks to climate change is poorly understood. While some field studies have focused on N cycling in bogs, little is known about N inputs and transformations within boreal fens. We recently initiated a large scale manipulation of soil temperature and water table in a moderately rich fen situated near the Bonanza Creek LTER site, outside Fairbanks, Alaska (the Alaska Peatland Experiment or APEX; www.apex.msu.edu). As part of this experiment, we hypothesized that water table height regulates microbial reduction - oxidation (redox) reactions in organic soils. This may alter the potential for nitrification and denitrification, and therefore, concentrations of ammonium (NH4+), and nitrate (NO3-), and fluxes of nitrous oxide (N2O) in fen ecosystems. Denitrification however, may be limited by low NO3- concentrations in this fen, which is dominated by a mix of herbaceous species, brown mosses, and Sphagnum. We also hypothesized that warming would increase N transformation rates by stimulating heterotrophic microbial activity, leading to variation in N mineralization rates and N availability. We established three water table plots (control, raised, lowered), each about 120 m2 in area. Water table levels at the lowered and raised plots were manipulated using drainage ditches and solar powered pumping techniques, respectively, and were kept at between 5-10 cm below and at 5 cm above the control plot. At 3 of the 6 sub plots within each water table plot, we constructed replicate open top chambers (OTCs) to passively increase surface temperatures by about 1 ° C. In the first season of measurements at the APEX

  2. Rapid deglacial and early Holocene expansion of peatlands in Alaska

    PubMed Central

    Jones, Miriam C.; Yu, Zicheng

    2010-01-01

    Northern peatlands represent one of the largest biospheric carbon (C) reservoirs; however, the role of peatlands in the global carbon cycle remains intensely debated, owing in part to the paucity of detailed regional datasets and the complexity of the role of climate, ecosystem processes, and environmental factors in controlling peatland C dynamics. Here we used detailed C accumulation data from four peatlands and a compilation of peatland initiation ages across Alaska to examine Holocene peatland dynamics and climate sensitivity. We find that 75% of dated peatlands in Alaska initiated before 8,600 years ago and that early Holocene C accumulation rates were four times higher than the rest of the Holocene. Similar rapid peatland expansion occurred in West Siberia during the Holocene thermal maximum (HTM). Our results suggest that high summer temperature and strong seasonality during the HTM in Alaska might have played a major role in causing the highest rates of C accumulation and peatland expansion. The rapid peatland expansion and C accumulation in these vast regions contributed significantly to the peak of atmospheric methane concentrations in the early Holocene. Furthermore, we find that Alaskan peatlands began expanding much earlier than peatlands in other regions, indicating an important contribution of these peatlands to the pre-Holocene increase in atmospheric methane concentrations. PMID:20368451

  3. 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

  4. Peatland Carbon Dynamics in Alaska During Past Warm Climates

    NASA Astrophysics Data System (ADS)

    Yu, Z.; Cleary, K.; Massa, C.; Hunt, S. J.; Klein, E. S.; Loisel, J.

    2013-12-01

    Peatlands represent a large belowground carbon (C) pool in the biosphere. However, how peatland C sequestration capacity varies with changes in climate and climate-induced disturbance is still poorly understood and debated. Here we summarize results from Alaskan peatlands to document how peat C accumulation has responded to past warm climate intervals. We find that the greatest C accumulation rates at sites from the Kenai Peninsula to the North Slope occurred during the Holocene thermal maximum (HTM) in the early Holocene. This time period also corresponds with explosive formation and expansion of new peatlands on the landscape across Alaska. In addition, we note that many peatlands that existed during the earlier Holocene on the North Slope have disappeared and are presently covered by mineral soils under tundra or sandy deposits. During the Medieval Climate Anomaly (MCA) around 1000-500 years ago, several peatlands in Alaska show high rates of C accumulation when compared to the period before the MCA during the Neoglacial or the following Little Ice Age period. Altogether, our results indicate that the Alaskan landscape was very different during the last 10,000 years and that peatlands can rapidly accumulate C under warm climatic conditions. We speculate that warmth-stimulated increase in plant production surpasses increase in peat decomposition during the early Holocene, and potentially also during the MCA. Other factors that might have contributed to rapid peat accumulation during the early Holocene include increased summer sunlight, lowered sea levels, and decreased sea-ice cover/duration. Summer insolation was ca. 8% higher than today during the early Holocene due to orbital variations, which likely promoted plant productivity by increasing growing seasons sunlight. Furthermore, lower sea levels and exposed shallow continental shelves in the Beaufort Sea (Arctic Ocean) would have made the present-day Arctic Coastal Plain more continental, with warmer summers

  5. FY10 RARE Final Report to Region 10: The functional Assessment of Alaska Peatlands in Cook Inlet Basin - report

    EPA Science Inventory

    Peatlands in south central Alaska form the predominant wetland class in the lowlands that encompass Cook Inlet. These peatlands are also in areas of increasing human development in Alaska. Currently Alaska peatlands are extensive and largely pristine. This study focused onobtaini...

  6. Peatland Carbon Accumulation in Southern Alaska During the Past 1000 Years: A Comparative Study of Hydrology and Carbon Accumulation in Four Peatlands

    NASA Astrophysics Data System (ADS)

    Klein, E. S.; Booth, R. K.; Yu, Z.

    2012-12-01

    North American peatlands are the largest C reservoir of any ecosystem type, and Alaskan peatlands contain greater than half of the C storage of United States' peatlands. Peatland C accumulation rates (PCAR) are controlled by the relative rates of production and decomposition, and the rate of these processes is affected by many factors, including temperature, hydrology, and vegetation. Understanding how this carbon pool will respond to climate changes is important for evaluating potential earth-system feedbacks. Critical to this goal is a better understanding of how PCAR varies among different climate zones and peatland types. We developed coupled studies of peatland paleohydrology and PCAR from four different Sphagnum-dominated peatlands in Alaska, two in the Southcentral (SC) region and two in the wetter and warmer Southeast (SE) region. Peatland types included a kettle peatland perched on a moraine and a lowland peatland occupying a paleo outwash channel in the SC region, as well as a raised peatland and a sloping peatland in the SE region. Past PCAR and hydrology of these peatlands, inferred from testate amoebae and loss-on-ignition analyses, were compared to well-documented climate and temperature changes of the past 1000 years, like the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). Results indicate heterogeneous patterns of PCAR at the four sites. For example, the raised peatland in the SE region had an average PCAR of 52 gC/m2/yr, whereas the other three sites had average values between 31-35 gC/m2/yr. Interestingly, testate amoebae indicated that the raised peatland had the driest average surface-moisture among the sites, possibly suggesting high temperature sensitivity to PCAR. Temporal patterns of PCAR also varied considerably among sites, with peatlands in the SE region exhibiting somewhat greater centennial-scale variability in PCAR during the past 1000 years than those of the SC region. Reconstructed water-table depths were also more

  7. The Holocene Thermal Maximum as a Time of Rapid Peat Accumulation and Peatland Expansion in Alaska

    NASA Astrophysics Data System (ADS)

    Jones, M. C.; Yu, Z.; Peteet, D. M.

    2009-05-01

    High latitudes are particularly sensitive to climate warming resulting from a number of important positive feedbacks, including increasing albedo from changing sea ice extent, snow and vegetation cover, and feedbacks to the carbon cycle. The fate of high latitude ecosystems and associated climate feedbacks in response to warming remains uncertain, particularly in boreal peatlands, which store roughly one-third of the global carbon pool. In order to understand how peatlands respond to climate warming, we examined Holocene carbon accumulation rates from four peatlands on the Kenai Peninsula, Alaska, focusing on the early Holocene (~11,000-9000 cal yr BP), a time when the climate was warmer than today. Basal dates from over 200 peat cores across Alaska were compiled to examine the timing and spatial distribution of peatland initiation across Alaska, and available pollen data from the North American Pollen Database (NAPD) and the Paleoenvironmental Arctic Sciences (PARCS) databases were used to examine associated vegetation distribution patterns. Our study reveals that the highest rates of carbon accumulation on the Kenai Peninsula occurred during the early Holocene Thermal Maximum (HTM), which also corresponds to the highest number of peat basal dates both on the Kenai and across Alaska, indicating that not only vertical peat growth but also lateral peatland expansion was high. We suggest that the warm summers and longer growing season during the early Holocene in Alaska resulted in high net primary productivity (NPP), rapid peat burial, and the greatest carbon accumulation rates. Rapid rates of accumulation and burial may have minimized the effects of aerobic decomposition. In addition, a change in the seasonal timing of precipitation and moisture availability and an increase in summer precipitation may have decreased drought stress, promoting peatland initiation and peat growth. We also speculate that the dominance of broad-leafed deciduous forests and abundant

  8. The response of soil organic carbon of a rich fen peatland in interior Alaska to projected climate change

    USGS Publications Warehouse

    Fan, Zhaosheng; McGuire, Anthony David; Turetsky, Merritt R.; Harden, Jennifer W.; Waddington, James Michael; Kane, Evan S.

    2013-01-01

    It is important to understand the fate of carbon in boreal peatland soils in response to climate change because a substantial change in release of this carbon as CO2 and CH4 could influence the climate system. The goal of this research was to synthesize the results of a field water table manipulation experiment conducted in a boreal rich fen into a process-based model to understand how soil organic carbon (SOC) of the rich fen might respond to projected climate change. This model, the peatland version of the dynamic organic soil Terrestrial Ecosystem Model (peatland DOS-TEM), was calibrated with data collected during 2005–2011 from the control treatment of a boreal rich fen in the Alaska Peatland Experiment (APEX). The performance of the model was validated with the experimental data measured from the raised and lowered water-table treatments of APEX during the same period. The model was then applied to simulate future SOC dynamics of the rich fen control site under various CO2 emission scenarios. The results across these emissions scenarios suggest that the rate of SOC sequestration in the rich fen will increase between year 2012 and 2061 because the effects of warming increase heterotrophic respiration less than they increase carbon inputs via production. However, after 2061, the rate of SOC sequestration will be weakened and, as a result, the rich fen will likely become a carbon source to the atmosphere between 2062 and 2099. During this period, the effects of projected warming increase respiration so that it is greater than carbon inputs via production. Although changes in precipitation alone had relatively little effect on the dynamics of SOC, changes in precipitation did interact with warming to influence SOC dynamics for some climate scenarios.

  9. Quantifying the Distribution and Landscape Controls of Peatlands and Organic Layer Thickness within Alaska

    NASA Astrophysics Data System (ADS)

    Wylie, B. K.; Pastick, N.; Jorgenson, T.; Nield, S.; Johnson, K. D.

    2014-12-01

    The northern circumpolar region is estimated to contain 50 % of the global belowground carbon pool and is experiencing climate change at rates higher than anywhere else globally. Surface organic horizons associated with these immense carbon pools are important to ecosystem functioning in terms of soil moisture and temperature regulations, permafrost degradation, successional trajectories, and soil respiration levels. However, fire-induced changes to surface organics and their distribution are poorly understood, especially on landscape scales. These ambiguities make future predictions uncertain for these significant carbon pools, which have the potential for significant feedbacks to global warming. Moreover, given the significant impacts and increasing severity and amount of fires in boreal systems, the spatial quantification of post-fire surface organic thickness is important for ecosystem model calibrations and comparisons, and can improve future projections of vegetation types and albedo, carbon stocks and fluxes, and future thaw depths. Here we present the results of pioneering studies that quantified the distribution and controls of peatlands and soil organic layer thickness in Alaska through the use of statistical models, field data, spatial analyses, and remote sensing (Landsat). Our empirical modeling approach enabled us to produce medium-resolution (30-m pixels) maps of peatlands and organic layer thickness throughout Alaska, which is important for land management practices and enhances the understanding of the risk and feedbacks associated with fires and climate feedbacks.

  10. Holocene peatland shifts in vegetation, carbon, and climate at Imnavait, Alaska

    NASA Astrophysics Data System (ADS)

    Peteet, D. M.; Nichols, J. E.; Ouni, S.; Pavia, F.; Pearl, Y.

    2012-12-01

    The Imnavait Creek basin (68 40'N, 149 20'W; elevation 875-945 m) in the foothills of the Brooks Range, AK has been well studied in terms of modern vegetational communities, hydrology, and soils. But paleoclimate and paleovegetation reconstructions are limited. We retrieved a 2-m peatland core to examine the macrofossil/biomarker/carbon sequestration history throughout the Holocene and late-glacial. AMS 14C dates of the macrofossil remains will allow us to calculate carbon sequestration rates. The Holocene history (the top meter) records marked shifts in vascular plant as well as bryophyte history. A tri-partite sequence is apparent, with Andromeda/Sphagnum remains abundant in the early Holocene. The absence of bryophytes and the presence of Eriophorum and Carex achenes characterize the mid-Holocene. Andromeda and Betula nana with Sphagnum remains are abundant in the upper 30 cm of the core. Hydrogen isotope ratios of leaf wax alkanes record higher effective moisture in the early and late Holocene, suggesting more evaporative loss in the mid-Holocene which is characterized by Eriophorum. We compare our results with previously observed palynological shifts from lakes in the region and place this Arctic paleorecord in a larger perspective of peatland histories in a N-S transect covering nearly 10 degrees of latitude across Alaska. This tripartite pattern of effective moisture appears to be the same throughout the Alaskan transect, suggesting strong climatic control.

  11. Understanding Carbon Storage in Permafrost Peatlands: Examples from Thermokarst Landscapes in Interior Alaska

    NASA Astrophysics Data System (ADS)

    Jones, M.; Harden, J. W.; O'Donnell, J. A.; Manies, K.; Jorgenson, T.

    2014-12-01

    As the climate at high latitudes continues to warm, permafrost is becoming increasingly vulnerable to thaw, particularly in the zone of discontinuous permafrost where mean annual air temperatures hover close to zero. Permafrost thaw has dramatic consequences on local hydrology, ecology, and the carbon (C) balance of these ecosystems. The degree to which permafrost peatlands become C sources or sinks following permafrost thaw remains a topic of much debate, owing to the difficulty in accurately dating cores from collapse-scar bogs and in understanding the vulnerability of the formerly forested peat to decomposition immediately following thaw and inundation. Here we use a combination of a chronosequence, paleoenvironmental, and modeling approaches from a permafrost peat plateau interspersed with collapse-scar bogs in Interior Alaska to address how C storage is impacted on timescales from decades to millennia following permafrost thaw. Our initial results indicate that C stocks are lowest in young (years to decades) and intermediate (decades to centuries) collapse-scar bogs, but that net C stocks in old (centuries to millennia) bogs can be as high as in permafrost plateaus. Thawed forested plateau peat is subject to rapid decomposition in the years to decades following thaw, but that rate of loss slows over time. We hypothesize that this is because the labile C pool is preferentially consumed and quickly exhausted by soil microbes. Meanwhile, post-thaw collapse-scar bog peat accumulates rapidly at the surface, and our data show that on longer centennial to millennial timescales, this near-surface C may offset initial post-thaw losses at depth. Collapse-scar bog peat accumulation rates outpace the former-plateau peat loss in a matter of years to decades. Older landscapes (i.e., those that began accumulating peat many thousands of years ago), are subject to greater C loss following thaw than are younger landscapes(i.e., those that initiated only a couple thousand years

  12. Microbial enzyme activities of peatland soils in south central Alaska lowlands

    EPA Science Inventory

    Microbial enzyme activities related to carbon and nutrient acquisition were measured on Alaskan peatland soils as indicators of nutrient limitation and biochemical sustainability. Peat decomposition is mediated by microorganisms and enzymes that in turn are limited by various ph...

  13. Effect of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence

    NASA Astrophysics Data System (ADS)

    Johnston, Carmel E.; Ewing, Stephanie A.; Harden, Jennifer W.; Varner, Ruth K.; Wickland, Kimberly P.; Koch, Joshua C.; Fuller, Christopher C.; Manies, Kristen; Torre Jorgenson, M.

    2014-08-01

    Permafrost soils store over half of global soil carbon (C), and northern frozen peatlands store about 10% of global permafrost C. With thaw, inundation of high latitude lowland peatlands typically increases the surface-atmosphere flux of methane (CH4), a potent greenhouse gas. To examine the effects of lowland permafrost thaw over millennial timescales, we measured carbon dioxide (CO2) and CH4 exchange along sites that constitute a ˜1000 yr thaw chronosequence of thermokarst collapse bogs and adjacent fen locations at Innoko Flats Wildlife Refuge in western Alaska. Peak CH4 exchange in July (123 ± 71 mg CH4-C m-2 d-1) was observed in features that have been thawed for 30 to 70 (<100) yr, where soils were warmer than at more recently thawed sites (14 to 21 yr; emitting 1.37 ± 0.67 mg CH4-C m-2 d-1 in July) and had shallower water tables than at older sites (200 to 1400 yr; emitting 6.55 ± 2.23 mg CH4-C m-2 d-1 in July). Carbon lost via CH4 efflux during the growing season at these intermediate age sites was 8% of uptake by net ecosystem exchange. Our results provide evidence that CH4 emissions following lowland permafrost thaw are enhanced over decadal time scales, but limited over millennia. Over larger spatial scales, adjacent fen systems may contribute sustained CH4 emission, CO2 uptake, and DOC export. We argue that over timescales of decades to centuries, thaw features in high-latitude lowland peatlands, particularly those developed on poorly drained mineral substrates, are a key locus of elevated CH4 emission to the atmosphere that must be considered for a complete understanding of high latitude CH4 dynamics.

  14. Peatland Carbon Dynamics on the North Slope of Alaska During the Holocene: The Role of Climate, Sea Ice, and Buried Peat

    NASA Astrophysics Data System (ADS)

    Yu, Zicheng; Massa, Charly; Cleary, Kathleen; Jones, Benjamin; Grosse, Guido

    2014-05-01

    Our recent and ongoing data syntheses indicate that peatlands accumulated more carbon (C) during past warm climate intervals in the circum-Arctic region, including Alaska. In particular, peak C accumulations have been observed during the Holocene Thermal Maximum (HTM) in the early Holocene when summer insolation was higher. However, we do not know the regional patterns and impacts of sea-ice change on Holocene peat C accumulation, especially around the Arctic Ocean where increased vegetation productivity has already been linked to sea ice declines in recent decades. Here we review Holocene peatland and tundra C accumulation records on the North Slope, along with our preliminary results, to investigate spatiotemporal pattern of C accumulation and the possible role of sea-ice change. As in many other northern high-latitude regions, most peatlands on the North Slope initiated in the early Holocene. Several discontinuous and low-resolution peat accumulation records from the region appear to show high accumulation rates or high C content in the early Holocene. In addition, we note that many peatlands that existed during the earlier Holocene on the North Slope have disappeared and are presently covered by mineral soils under tundra or eolian sandy deposits, indicating that current peatland extent is only a fraction of early Holocene extent. In contrast to highest C accumulation rates in the early Holocene, our preliminary results from a 70-cm-long peat core (lat. 70.71 N; long. 153.87 W) from northwest Teshekpuk Lake, near the Teshekpuk Lake Observatory on the Arctic Coastal Plain, about 10 km from the Arctic Ocean, shows a very different pattern. The highest C accumulation of 12.7 gC/m2/yr is observed after 2.9 ka, much higher than the rate of 3.8 gC/m2/yr at 8.1-2.9 ka. Furthermore, the period with high C rates after 2.9 ka at this site was dominated by well-preserved peat mosses (Sphagnum) and with abundant leaf fragments, likely from dwarf birch (Betula nana). This

  15. Will climate change exceed the resilience limits of western Canadian peatlands?

    NASA Astrophysics Data System (ADS)

    Turetsky, M. R.; Benscoter, B.; Olefeldt, D.

    2014-12-01

    Northern peatlands have served as persistent, small sinks of atmospheric CO2 throughout the Holocene. In western Canada, peatlands exist on the drier spectrum of global peatland distributions. As a result, peatlands in this region are drier (e.g., no/few open pools in bogs and poor fens) and all bogs are treed. Because they occupy this climate space, continental peatlands might be regarded as being vulnerable to future warming and drying. On the other hand, these peatlands and their plant communities might already be adapted to drier conditions, conferring some resistance to climate change. The position of the water table within a peatland serves as a dominant control on peat accumulation rates, as it influences plant structure and productivity, decomposition, and dissolved carbon export. Many studies predict that lower water table position, in response to enhanced evapotranspiration or drought, will cause peatlands to release stored C back to the atmosphere, indicative of a state change to an ecosystem type that no longer supports long-term peat accumulation. A 10-yr drainage experiment at the Alaska Peatland Experiment (APEX) sites showed that lowering the water table made a rich fen more of an atmospheric C source, primarily by altering plant species composition and lowering plant primary production rather than by increasing soil CO2 flux. Multi-decadal drainage of Canadian peatlands also resulted in changes in plant species composition, with increasing tree and shrub canopy coverage and declines in moss abundance. Increased forestation in western Canadian peatlands will have large impacts on fire danger, which also has the potential to cause long-term shifts in plant and ecosystem structure, either through severe burning of surface peat layers or by inducing permafrost thaw. This talk will present findings from empirical and modeling studies examining peatland responses to warming, drought, permafrost thaw, and wildfires. Within the context of these dominant

  16. Short term response of a peatland to warming and drought - climate manipulation experiment in W Poland

    NASA Astrophysics Data System (ADS)

    Juszczak, Radosław; Chojnicki, Bogdan; Urbaniak, Marek; Leśny, Jacek; Silvennoinen, Hanna; Lamentowicz, Mariusz; Basińska, Anna; Gąbka, Maciej; Stróżecki, Marcin; Samson, Mateusz; Łuców, Dominika; Józefczyk, Damian; Hoffmann, Mathias; Olejnik, Janusz

    2016-04-01

    Central European peatlands are highly vulnerable as potential sources of carbon (C) to the atmosphere under anticipated climate changes, namely warming and drought (Fenner & Freeman 2011). We carried out a field manipulation experiment at Rzecin peatland in Poland to assess how those changes impact carbon balance, vegetation and water chemistry. The field site consists of three times replicated treatments (control, CO; simulated warming, W; prolonged drought, D and warming & drought, W+D). Temperature (T) was increased year around with infrared heaters (400W × 4 per site, approx. 60 Wṡm‑2 addition of LW radiation, Kimball 2005) and precipitation was reduced with automatic curtain during growth seasons at night. The manipulation was successful yielding up to 0.4 oC and 1.0 oC T increases in air (30 cm height) and soil (5 cm depth), respectively, as well as a 35 % lower precipitation (in 2015). To study the C exchange we developed an automatic mobile platform for measuring CO2/CH4/H2O fluxes (LGR) as well as for 13CO2 and 13CH4 fluxes (PICARRO CRDS G2201-i) with dynamic ecosystem chambers (for NEE and Reco) and for simultaneous measurements of surface optical properties. Gap filling of the fluxes was done according to Hoffmann et al. 2015. In the very dry 2015, Rzecin peatland was a net source of CO2to the atmosphere (80 gCṡm‑2yr‑1). Warming and drought considerably diminished the source strength (7 gCṡm‑2yr‑1at the W+D site), due to lower cumulative respiration (Reco the smallest, 610 gC m‑2yr‑1, at W+D site). The highest CO2 emissions were measured from the site that was only warmed (W site, Reco 680 gCṡm‑2yr‑1), emphasizing the importance of drought in inhibiting respiration. Temperature increase also provoked the productivity (highest GPP at W site, -620 gCṡm‑2yr‑1), while drought yielded the lowest productivity (lowest GPP at D site, -550 gCṡm‑2yr‑1). Different vegetation parameters further support the C exchange estimates

  17. Cultural Diversity and the Experiences of Alaska Native Nursing Students

    ERIC Educational Resources Information Center

    Gilmon, Margaret E.

    2012-01-01

    The purpose of this ethnonursing research study was to discover, describe, and systematically analyze the care expressions, practices, and patterns of Alaska Native nurses within the context of their nursing school experience. The goals of this study were to identify generic and professional care factors that promote the academic success of Alaska…

  18. Water Research within the SPRUCE Experiment, a Large-Scale Study of Climate Change Effects on a Northern Peatland

    NASA Astrophysics Data System (ADS)

    Mulholland, P. J.; Sebestyen, S. D.; Hanson, P. J.; Warren, J.; Kolka, R. K.

    2010-12-01

    Scientists at the Oak Ridge National Laboratory and the USDA Forest Service along with cooperating research institutions are developing a large-scale ecosystem study in which temperature and carbon dioxide will be experimentally increased to quantify effects of climatic forcing on ecological, hydrological, and biogeochemical processes in a northern peatland. In this poster, we provide an overview of the water science research directions within the Spruce and Peatland Responses Under Climate and Environmental change Experiment (SPRUCE) that will occur at the Marcell Experiment Forest in northern Minnesota, USA. Design and prototyping is now occurring with full operation for 10 years starting in 2013. Air and soil temperatures inside replicated 12-m diameter, open-topped chambers will be maintained at ambient, +3, +6, and +9 degrees Celsius with enhanced carbon dioxide (+900 ppm in the ambient and +6 degree treatments). We will quantify changes in the timing and magnitude of runoff due to earlier snowmelt and longer growing seasons as well as associated changes in runoff chemistry. Measurements of plant-water, physiological, and vapor flux responses from the chambers will advance our understanding of hydrological responses and thresholds of climate tipping points. This experiment will provide quantitative evidence of the effects of climatic forcing by temperature and elevated carbon dioxide on northern peatland ecosystems and the vast stores of carbon that are associated with the hydrology and biogeochemistry of these globally widespread landscape features. The data are also crucial to predicting feedbacks on global climate as well as water availability, solute yields, and biogeochemical transformations in these ecosystems.

  19. Characteristics of Gaseous Carbon Emission from a Tropical Peatland Fire: A Plot-Scale Field Experiment in Central Kalimantan, Indonesia

    NASA Astrophysics Data System (ADS)

    Hamada, Y.; Darung, U.; Limin, S. H.; Hatano, R.

    2014-12-01

    Tropical peatland in Southeast Asia is a vast reservoir of terrestrial carbon, which covers 24.8 million hectares and stores 68.5 PgC peat, equal to 11-14% of global peat carbon. In recent decades, large scale peatland fire has occurred frequently in that region, in which many areas of peatland were reclaimed with intention to use the land for forest plantation and rice paddy. We conducted a plot-scale peat burning experiment to elucidate the characteristics of gaseous carbon emission from a tropical peatland fire at the ground level. The experimental site was established at an open area 20 km southeast from Palangka Raya, Central Kalimantan Province, Indonesia. The size of the burning plot is 4 m in length and 3 m in width. Gas samples were collected at heights of 1.0, 0.5, 0.0 (aboveground), -0.1 and -0.2 m (belowground) through stainless steel and/or aluminum tubes settled across the edge of the plot. The concentrations of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4) and particulate matter (PM) was determined. Soil temperature was recorded every 10 minutes 0.1 and 0.2 m below the ground surface. Twelve iron rods were installed in 1-m by 1-m square grid to determine the depth of burn scar. After ignition, flaming stage of peat burning was ceased within 1-2 hours. The following smoldering stage continued for a week. In the flaming stage, soil temperature at -0.1 m increased tentatively. After the smoldering stage began, the temperature rapidly increased to 350-450°C. Response of soil temperature at -0.2 m was less prominent. Concentrations of gaseous components became maximal in the flaming stage. During the smoldering stage, the concentrations gradually decreased. The influence of burning on CO2 and PM was prominently remained at -0.1 m, whereas those at -0.2 m were not so much. The averaged burnt depth was 5.8±5.1 cm. Based on bulk density of 0.22 g/cm3 and carbon content of 55.5%, the amount of carbon lost from the plot was 85.3 kg. Most of the

  20. Assessing Links Between Water and Carbon Storage in Indonesian Peatlands Using Data from the Gravity Recovery and Climate Experiment

    NASA Astrophysics Data System (ADS)

    Swails, E.; Reager, J. T., II; Randerson, J. T.; Famiglietti, J. S.; Lawrence, D.; Yu, K.

    2014-12-01

    Deforestation and drainage of tropical peat swamp forests for conversion to other uses results in a loss of carbon storage through the clearing and burning of forest vegetation as well as decomposition of peat soils and increased frequency of fires following drainage. We used Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage observations and a global forest cover change product to investigate trends in terrestrial water storage associated with land use conversion in Indonesian peatlands between 2002 and 2012. Our initial analysis indicated that secular trends in GRACE terrestrial water storage were consistent with the spatial distribution of peatlands drained for the establishment of oil palm plantations. A decreasing trend in GRACE terrestrial water storage measurements over the observation period indicated a substantial decrease in water table heights. Combining this information with measurements of bulk density and carbon content of surface peat layers, we estimated potential emissions from carbon stocks now vulnerable to oxidation. Independent measurements of fire carbon emissions were used to estimate the fraction of committed emission that was combusted. Our research represents the first known application of GRACE data to assess loss of soil carbon storage associated with depletion of soil water.

  1. Trace gas responses in a climate change experiment in northern peatlands

    SciTech Connect

    Bridgham, S.D.; Pastor, J.; Updegraff, K.

    1995-09-01

    We established 54 mesocosms of 2.2 m{sup 2} and approximately 0.6 m depth with intact vegetation communities, with half originating from a poor-intermediate fen and half from a bog in northern Minnesota. The mesocosms were subjected to a series of water-table (0,-10,-20 cm) and heating treatments, with the heating treatments from overhead infrared lamps (full on, half on, ambient). Heating began in late summer 1994, and gas flux measurements were taken until the onset of winter. The first year results indicate peatland type and water-table treatment had highly significant effects on CH{sub 4} emissions, while the effect of heating treatment was weaker (P=0.07). Overall CH{sub 4} fluxes were higher in bog than in fen mesocosms. Despite the significant treatment effects, a multiple regression with water-table depth and soil temperature as the independent variables only predicted 14% and 34% of the variation in CH{sub 4} flux in the bog and fen mesocosms, respectively. CO{sub 2} emissions (net ecosystem respiration) were significantly affected by peatland type (higher in bogs) and heat treatment, but not but by water-table treatment. Soil temperature predicted 34% and 48% of the CO{sub 2} flux in the bog and fen mesocosms, respectively. These preliminary results indicate that climate change will have a significant impact on trace gas emissions in northern peatlands, but that much of the variability in emission cannot be explained by environmental correlates, even under carefully controlled conditions.

  2. Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this spectacular MODIS image from November 7, 2001, the skies are clear over Alaska, revealing winter's advance. Perhaps the most interesting feature of the image is in its center; in blue against the rugged white backdrop of the Alaska Range, Denali, or Mt. McKinley, casts its massive shadow in the fading daylight. At 20,322 ft (6,194m), Denali is the highest point in North America. South of Denali, Cook Inlet appears flooded with sediment, turning the waters a muddy brown. To the east, where the Chugach Mountains meet the Gulf of Alaska, and to the west, across the Aleutian Range of the Alaska Peninsula, the bright blue and green swirls indicate populations of microscopic marine plants called phytoplankton. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  3. Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this spectacular MODIS image from November 7, 2001, the skies are clear over Alaska, revealing winter's advance. Perhaps the most interesting feature of the image is in its center; in blue against the rugged white backdrop of the Alaska Range, Denali, or Mt. McKinley, casts its massive shadow in the fading daylight. At 20,322 ft (6,194m), Denali is the highest point in North America. South of Denali, Cook Inlet appears flooded with sediment, turning the waters a muddy brown. To the east, where the Chugach Mountains meet the Gulf of Alaska, and to the west, across the Aleutian Range of the Alaska Peninsula, the bright blue and green swirls indicate populations of microscopic marine plants called phytoplankton.

  4. Drained coastal peatlands: A potential nitrogen source to marine ecosystems under prolonged drought and heavy storm events-A microcosm experiment.

    PubMed

    Wang, Hongjun; Richardson, Curtis J; Ho, Mengchi; Flanagan, Neal

    2016-10-01

    Over the past several decades there has been a massive increase in coastal eutrophication, which is often caused by increased runoff input of nitrogen from landscape alterations. Peatlands, covering 3% of land area, have stored about 12-21% of global soil organic nitrogen (12-20Pg N) around rivers, lakes and coasts over millennia and are now often drained and farmed. Their huge nitrogen pools may be released by intensified climate driven hydrologic events-prolonged droughts followed by heavy storms-and later transported to marine ecosystems. In this study, we collected peat monoliths from drained, natural, and restored coastal peatlands in the Southeastern U.S., and conducted a microcosm experiment simulating coupled prolonged-drought and storm events to (1) test whether storms could trigger a pulse of nitrogen export from drought-stressed peatlands and (2) assess how differentially hydrologic managements through shifting plant communities affect nitrogen export by combining an experiment of nitrogen release from litter. During the drought phase, we observed a significant temporal variation in net nitrogen mineralization rate (NMR). NMR spiked in the third month and then decreased rapidly. This pattern indicates that drought duration significantly affects nitrogen mineralization in peat. NMR in the drained site reached up to 490±110kgha(-1)year(-1), about 5 times higher than in the restored site. After the 14-month drought phase, we simulated a heavy storm by bringing peat monoliths to saturation. In the discharge waters, concentrations of total dissolved nitrogen in the monoliths from the drained site (72.7±16.3mgL(-1)) was about ten times as high as from the restored site. Our results indicate that previously drained peatlands under prolonged drought are a potent source of nitrogen export. Moreover, drought-induced plant community shifts to herbaceous plants substantially raise nitrogen release with lasting effects by altering litter quality in peatlands. PMID

  5. Mitigating wildfire carbon loss in managed northern peatlands through restoration.

    PubMed

    Granath, Gustaf; Moore, Paul A; Lukenbach, Maxwell C; Waddington, James M

    2016-01-01

    Northern peatlands can emit large amounts of carbon and harmful smoke pollution during a wildfire. Of particular concern are drained and mined peatlands, where management practices destabilize an array of ecohydrological feedbacks, moss traits and peat properties that moderate water and carbon losses in natural peatlands. Our results demonstrate that drained and mined peatlands in Canada and northern Europe can experience catastrophic deep burns (>200 t C ha(-1) emitted) under current weather conditions. Furthermore, climate change will cause greater water losses in these peatlands and subject even deeper peat layers to wildfire combustion. However, the rewetting of drained peatlands and the restoration of mined peatlands can effectively lower the risk of these deep burns, especially if a new peat moss layer successfully establishes and raises peat moisture content. We argue that restoration efforts are a necessary measure to mitigate the risk of carbon loss in managed peatlands under climate change. PMID:27346604

  6. Mitigating wildfire carbon loss in managed northern peatlands through restoration

    PubMed Central

    Granath, Gustaf; Moore, Paul A.; Lukenbach, Maxwell C.; Waddington, James M.

    2016-01-01

    Northern peatlands can emit large amounts of carbon and harmful smoke pollution during a wildfire. Of particular concern are drained and mined peatlands, where management practices destabilize an array of ecohydrological feedbacks, moss traits and peat properties that moderate water and carbon losses in natural peatlands. Our results demonstrate that drained and mined peatlands in Canada and northern Europe can experience catastrophic deep burns (>200 t C ha−1 emitted) under current weather conditions. Furthermore, climate change will cause greater water losses in these peatlands and subject even deeper peat layers to wildfire combustion. However, the rewetting of drained peatlands and the restoration of mined peatlands can effectively lower the risk of these deep burns, especially if a new peat moss layer successfully establishes and raises peat moisture content. We argue that restoration efforts are a necessary measure to mitigate the risk of carbon loss in managed peatlands under climate change. PMID:27346604

  7. Mitigating wildfire carbon loss in managed northern peatlands through restoration

    NASA Astrophysics Data System (ADS)

    Granath, Gustaf; Moore, Paul A.; Lukenbach, Maxwell C.; Waddington, James M.

    2016-06-01

    Northern peatlands can emit large amounts of carbon and harmful smoke pollution during a wildfire. Of particular concern are drained and mined peatlands, where management practices destabilize an array of ecohydrological feedbacks, moss traits and peat properties that moderate water and carbon losses in natural peatlands. Our results demonstrate that drained and mined peatlands in Canada and northern Europe can experience catastrophic deep burns (>200 t C ha‑1 emitted) under current weather conditions. Furthermore, climate change will cause greater water losses in these peatlands and subject even deeper peat layers to wildfire combustion. However, the rewetting of drained peatlands and the restoration of mined peatlands can effectively lower the risk of these deep burns, especially if a new peat moss layer successfully establishes and raises peat moisture content. We argue that restoration efforts are a necessary measure to mitigate the risk of carbon loss in managed peatlands under climate change.

  8. Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Though it's not quite spring, waters in the Gulf of Alaska (right) appear to be blooming with plant life in this true-color MODIS image from March 4, 2002. East of the Alaska Peninsula (bottom center), blue-green swirls surround Kodiak Island. These colors are the result of light reflecting off chlorophyll and other pigments in tiny marine plants called phytoplankton. The bloom extends southward and clear dividing line can be seen west to east, where the bloom disappears over the deeper waters of the Aleutian Trench. North in Cook Inlet, large amounts of red clay sediment are turning the water brown. To the east, more colorful swirls stretch out from Prince William Sound, and may be a mixture of clay sediment from the Copper River and phytoplankton. Arcing across the top left of the image, the snow-covered Brooks Range towers over Alaska's North Slope. Frozen rivers trace white ribbons across the winter landscape. The mighty Yukon River traverses the entire state, beginning at the right edge of the image (a little way down from the top) running all the way over to the Bering Sea, still locked in ice. In the high-resolution image, the circular, snow-filled calderas of two volcanoes are apparent along the Alaska Peninsula. In Bristol Bay (to the west of the Peninsula) and in a couple of the semi-clear areas in the Bering Sea, it appears that there may be an ice algae bloom along the sharp ice edge (see high resolution image for better details). Ground-based observations from the area have revealed that an under-ice bloom often starts as early as February in this region and then seeds the more typical spring bloom later in the season.

  9. The Alaska experience using store-and-forward telemedicine for ENT care in Alaska.

    PubMed

    Kokesh, John; Ferguson, A Stewart; Patricoski, Chris

    2011-12-01

    This article discusses the development, evaluation, and growth of telemedicine in Alaska. Store-and-forward telemedicine has been used to deliver ear, nose, and throat (ENT) care to rural Alaska since 2002. It has proved valuable in the treatment of many conditions of the head and neck, and it is particularly well suited for the diagnosis and treatment of ear disease. Usage has grown steadily as telemedicine has become widely accepted. Store-and-forward telemedicine has been shown within the Alaska Native Health System to improve access for care and reduce wait times, as well as decrease travel-associated costs for patients. PMID:22032488

  10. Economic Education Experiences of Award Winning Alaska Teachers.

    ERIC Educational Resources Information Center

    Thomas, Monica, Ed.

    Award-winning economic education projects devised by Alaska teachers included three elementary (K-6) projects and three second level (7-12) ones. Faith Greenough's students (Chinook Elementary School, Anchorage) compared Tlingit traditional and market economies in Alaska, so economics became an integrated part of elementary instruction. Marie…

  11. Quantifying landscape morphology influence on peatland lateral expansion using ground-penetrating radar (GPR) and peat core analysis

    NASA Astrophysics Data System (ADS)

    Loisel, Julie; Yu, Zicheng; Parsekian, Andrew; Nolan, James; Slater, Lee

    2013-06-01

    peatlands contain vast amounts of organic carbon. Large-scale datasets have documented spatial patterns of peatland initiation as well as vertical peat accumulation rates. However, the rate, pattern, and timing of lateral expansion across the northern landscape remain largely unknown. As peatland lateral extent is a key boundary condition constraining the dynamics of peatland systems, understanding this process is essential. Here we use ground penetrating radar (GPR) and peat core analysis to study the effect of local slope and topography on peatland development at a site in south-central Alaska. The study site is unique in that a thick tephra (volcanic ash) layer, visible in the GPR data, interrupted the peatland development for about one thousand years during the mid Holocene. In our analysis, this tephra layer serves as a re-initiation point for peatland development. By comparing the initial mineral basin vs. the post-tephra surfaces, the influence of topography and slope on peatland expansion rate and peat-carbon sequestration was analyzed. Our results show that (1) peatland surface slope becomes progressively shallower over the Holocene, (2) slope affects peatland lateral expansion nonlinearly, (3) the relationship between lateral expansion rate and slope follows a power-law behavior, and (4) peatland expansion becomes slope-limited above a threshold (0.5°). Furthermore, we propose a conceptual model linking slope to peatland lateral expansion where slope gradient and basin topography exert deterministic controls on peatland lateral expansion directly or through hydrology and vertical accumulation rates.

  12. A comprehensive data acquisition and management system for an ecosystem-scale peatland warming and elevated CO2 experiment

    DOE PAGESBeta

    Krassovski, M. B.; Riggs, J. S.; Hook, L. A.; Nettles, W. R.; Hanson, P. J.; Boden, T. A.

    2015-11-09

    Ecosystem-scale manipulation experiments represent large science investments that require well-designed data acquisition and management systems to provide reliable, accurate information to project participants and third party users. The SPRUCE project (Spruce and Peatland Responses Under Climatic and Environmental Change, http://mnspruce.ornl.gov) is such an experiment funded by the Department of Energy's (DOE), Office of Science, Terrestrial Ecosystem Science (TES) Program. The SPRUCE experimental mission is to assess ecosystem-level biological responses of vulnerable, high carbon terrestrial ecosystems to a range of climate warming manipulations and an elevated CO2 atmosphere. SPRUCE provides a platform for testing mechanisms controlling the vulnerability of organisms, biogeochemicalmore » processes, and ecosystems to climatic change (e.g., thresholds for organism decline or mortality, limitations to regeneration, biogeochemical limitations to productivity, and the cycling and release of CO2 and CH4 to the atmosphere). The SPRUCE experiment will generate a wide range of continuous and discrete measurements. In order to successfully manage SPRUCE data collection, achieve SPRUCE science objectives, and support broader climate change research, the research staff has designed a flexible data system using proven network technologies and software components. The primary SPRUCE data system components are the following; 1. data acquisition and control system – set of hardware and software to retrieve biological and engineering data from sensors, collect sensor status information, and distribute feedback to control components; 2. data collection system – set of hardware and software to deliver data to a central depository for storage and further processing; and 3. data management plan – set of plans, policies, and practices to control consistency, protect data integrity, and deliver data. This publication presents our approach to meeting the challenges of

  13. A comprehensive data acquisition and management system for an ecosystem-scale peatland warming and elevated CO2 experiment

    NASA Astrophysics Data System (ADS)

    Krassovski, M. B.; Riggs, J. S.; Hook, L. A.; Nettles, W. R.; Hanson, P. J.; Boden, T. A.

    2015-11-01

    Ecosystem-scale manipulation experiments represent large science investments that require well-designed data acquisition and management systems to provide reliable, accurate information to project participants and third party users. The SPRUCE project (Spruce and Peatland Responses Under Climatic and Environmental Change, http://mnspruce.ornl.gov) is such an experiment funded by the Department of Energy's (DOE), Office of Science, Terrestrial Ecosystem Science (TES) Program. The SPRUCE experimental mission is to assess ecosystem-level biological responses of vulnerable, high carbon terrestrial ecosystems to a range of climate warming manipulations and an elevated CO2 atmosphere. SPRUCE provides a platform for testing mechanisms controlling the vulnerability of organisms, biogeochemical processes, and ecosystems to climatic change (e.g., thresholds for organism decline or mortality, limitations to regeneration, biogeochemical limitations to productivity, and the cycling and release of CO2 and CH4 to the atmosphere). The SPRUCE experiment will generate a wide range of continuous and discrete measurements. To successfully manage SPRUCE data collection, achieve SPRUCE science objectives, and support broader climate change research, the research staff has designed a flexible data system using proven network technologies and software components. The primary SPRUCE data system components are the following: 1. data acquisition and control system - set of hardware and software to retrieve biological and engineering data from sensors, collect sensor status information, and distribute feedback to control components; 2. data collection system - set of hardware and software to deliver data to a central depository for storage and further processing; 3. data management plan - set of plans, policies, and practices to control consistency, protect data integrity, and deliver data. This publication presents our approach to meeting

  14. A comprehensive data acquisition and management system for an ecosystem-scale peatland warming and elevated CO2 experiment

    NASA Astrophysics Data System (ADS)

    Krassovski, M. B.; Riggs, J. S.; Hook, L. A.; Nettles, W. R.; Hanson, P. J.; Boden, T. A.

    2015-07-01

    Ecosystem-scale manipulation experiments represent large science investments that require well-designed data acquisition and management systems to provide reliable, accurate information to project participants and third party users. The SPRUCE Project (Spruce and Peatland Responses Under Climatic and Environmental Change, http://mnspruce.ornl.gov) is such an experiment funded by the Department of Energy's (DOE), Office of Science, Terrestrial Ecosystem Science (TES) Program. The SPRUCE experimental mission is to assess ecosystem-level biological responses of vulnerable, high carbon terrestrial ecosystems to a range of climate warming manipulations and an elevated CO2 atmosphere. SPRUCE provides a platform for testing mechanisms controlling the vulnerability of organisms, biogeochemical processes, and ecosystems to climatic change (e.g., thresholds for organism decline or mortality, limitations to regeneration, biogeochemical limitations to productivity, the cycling and release of CO2 and CH4 to the atmosphere). The SPRUCE experiment will generate a wide range of continuous and discrete measurements. To successfully manage SPRUCE data collection, achieve SPRUCE science objectives, and support broader climate change research, the research staff has designed a flexible data system using proven network technologies and software components. The primary SPRUCE data system components are: 1. Data acquisition and control system - set of hardware and software to retrieve biological and engineering data from sensors, collect sensor status information, and distribute feedback to control components. 2. Data collection system - set of hardware and software to deliver data to a central depository for storage and further processing. 3. Data management plan - set of plans, policies, and practices to control consistency, protect data integrity, and deliver data. This publication presents our approach to meeting the

  15. Resilience of Arctic Permafrost Carbon in Mackenzie River Basin: An Incubation Experiment to Observe Priming Potentials and Biodegradability of Arctic Permafrost Peatlands

    NASA Astrophysics Data System (ADS)

    Hedgpeth, A.; Beilman, D.; Crow, S. E.

    2015-12-01

    Arctic permafrost zones cover 25% of the Northern Hemisphere and hold 1672Pg of soil carbon (C) with 277Pg in Arctic permafrost peatlands, which is 1/3 of the CO2 in the atmosphere. This currently protected C is a potential source for increased emissions in a warmer climate. Longer growing seasons resulting in increased plant productivity above and below ground may create new labile C inputs with the potential to affect mineralization of previously stable SOM, known as the priming effect. This study examined the response of soil respiration to labile substrate addition in carbon-rich (42-48 %C) permafrost peatland soils along a N-S transect in the central Mackenzie River Basin (69.2-62.6°N). Active layer and near surface soils (surface Δ14C values > -140.0) were collected from four sites between -10.5 and -5.2 MAT. Soils were spiked with 0.5 mg D-glucose g-1soil, and incubated at 10°C for 23 days to determine potential, short term (i.e., apparent) priming effects. On average glucose addition increased respiration in all samples. One site showed priming evidence in active layer soils despite one-way ANOVA not illustrating statistically significant differences between control and treated final cumulative CO2. Apparent priming effects were seen in two near surface permafrost samples, however cumulative increases in CO2 were not identified as significant. When all results from all sites and depths were considered, the addition of glucose showed no significant effect on total CO2 production relative to controls (p=0.957), suggesting that these sites may be resilient to increased inputs in that little priming evidence was observed. To test the idea that the soils that showed priming effects are of poorer quality, we conducted an additional incubation experiment to explore the biodegradability of these permafrost peatland soils. Soils from these four sites were inoculated and incubated for 17 days. The two sites with observed priming showed the highest biodegradability

  16. Methanotrophs Contribute to Peatland Nitrogen

    NASA Astrophysics Data System (ADS)

    Larmola, Tuula; Leppänen, Sanna M.; Tuittila, Eeva-Stiina; Aarva, Maija; Merilä, Päivi; Fritze, Hannu; Tiirola, Marja

    2016-04-01

    Atmospheric nitrogen (N2) fixation is potentially an important N input mechanism to peatland ecosystems, but the extent of this process may have been underestimated because of the methods traditionally used inhibit the activity of methanothrophs. We examined the linkage of methane (CH4) oxidation and N2 fixation using 15N2 technique. Dominant flark and hummock Sphagnum species were collected from twelve pristine peatlands in Siikajoki, Finland, which varied in age from 200 to 2,500 y due to the postglacial rebound. The mosses were incubated in a two-day field 15N2 and 13CH4 pulse labelling experiment and the incorporation of 15N2 and 13CH4 in biomass was measured with Isotope Ratio Mass Spectrometer. The rates of Sphagnum-associated N2 fixation (0.1-2.9 g N m-2 y-1) were up to 10 times the current N deposition rates. Methane-induced N2 fixation contributed to over 1/3 of moss-associated N2 fixation in younger stages, but was switched off in old successional stages, despite active CH4 oxidation in these stages. Both the N2 fixation rates and the methanotrophic contribution to N2 fixation during peatland succession were primarily constrained by phosphorus availability. Previously overlooked methanotrophic N contribution may explain rapid peat and N accumulation during fen stages of peatland development. Reference. Larmola T., Leppänen S.M., Tuittila E.-S, Aarva M., Merilä P., Fritze H., Tiirola M. (2014) Methanotrophy induces nitrogen fixation during peatland development. Proceedings of the National Academy of Sciences USA 111 (2): 734-739.

  17. 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

  18. Interactive biotic and abiotic regulators of soil carbon cycling: evidence from controlled climate experiments on peatland and boreal soils.

    PubMed

    Briones, María Jesús I; McNamara, Niall P; Poskitt, Jan; Crow, Susan E; Ostle, Nicholas J

    2014-09-01

    Partially decomposed plant and animal remains have been accumulating in organic soils (i.e. >40% C content) for millennia, making them the largest terrestrial carbon store. There is growing concern that, in a warming world, soil biotic processing will accelerate and release greenhouse gases that further exacerbate climate change. However, the magnitude of this response remains uncertain as the constraints are abiotic, biotic and interactive. Here, we examined the influence of resource quality and biological activity on the temperature sensitivity of soil respiration under different soil moisture regimes. Organic soils were sampled from 13 boreal and peatland ecosystems located in the United Kingdom, Ireland, Spain, Finland and Sweden, representing a natural resource quality range of C, N and P. They were incubated at four temperatures (4, 10, 15 and 20 °C) at either 60% or 100% water holding capacity (WHC). Our results showed that chemical and biological properties play an important role in determining soil respiration responses to temperature and moisture changes. High soil C : P and C : N ratios were symptomatic of slow C turnover and long-term C accumulation. In boreal soils, low bacterial to fungal ratios were related to greater temperature sensitivity of respiration, which was amplified in drier conditions. This contrasted with peatland soils which were dominated by bacterial communities and enchytraeid grazing, resulting in a more rapid C turnover under warmer and wetter conditions. The unexpected acceleration of C mineralization under high moisture contents was possibly linked to the primarily role of fermented organic matter, instead of oxygen, in mediating microbial decomposition. We conclude that to improve C model simulations of soil respiration, a better resolution of the interactions occurring between climate, resource quality and the decomposer community will be required. PMID:24687903

  19. Do Peatlands Hibernate?

    NASA Astrophysics Data System (ADS)

    Dorrepaal, E.; Signarbieux, C.; Jassey, V.; Mills, R.; Buttler, A.; Robroek, B.

    2014-12-01

    Winter seasonality with extensive frost, snow cover and low incoming radiation characterise large areas at mid- and high latitudes, especially in mountain ranges and in the arctic. Given these adverse conditions, it is often assumed that ecosystem processes, such as plant photosynthesis, nutrient uptake and microbial activities, cease, or at best diminish to marginal rates compared to summer. However, snow is a good thermal insulator and a sufficiently thick snow cover might enable temperature-limited processes to continue in winter, especially belowground. Changes in winter precipitation may alter these conditions, yet, relative to the growing season, winter ecosystem processes remain poorly understood. We performed a snow-removal experiment on an ombrotrophic bog in the Swiss Jura mountains (1036 m.a.s.l.) to compare above- and belowground ecosystem processes with and without snow cover during mid- and late-winter (February and April) with the subsequent spring (June) and summer (July). The presence of 1m snow in mid-winter and 0.4m snow in late-winter strongly reduced the photosynthetic capacity (Amax) of Eriophorum vaginatum as well as the total microbial biomass compared to spring and summer values. Amax of Sphagnum magellanicum and uptake of 15N-labelled ammonium-nitrate by vascular plants were, however, almost as high or higher in mid- and late-winter as in summer. Snow removal increased the number of freeze-thaw cycles in mid-winter but also increased the minimum soil temperature in late-winter before ambient snow-melt. This strongly reduced all measured ecosystem processes in mid-winter compared to control and to spring and summer values. Plant 15N-uptake, Amax of Eriophorum and total microbial biomass returned to, or exceeded, control values soon before or after snowmelt. However, Sphagnum Amax and its length growth, as well as the structure of the microbial community showed clear carry-over effects of the reduced winter snow cover into next summer

  20. Red-Edge Spectral Reflectance as an Indicator of Surface Moisture Content in an Alaskan Peatland Ecosystem

    NASA Astrophysics Data System (ADS)

    McPartland, M.; Kane, E. S.; Turetsky, M. R.; Douglass, T.; Falkowski, M. J.; Montgomery, R.; Edwards, J.

    2015-12-01

    Arctic and boreal peatlands serve as major reservoirs of terrestrial organic carbon (C) because Net Primary Productivity (NPP) outstrips C loss from decomposition over long periods of time. Peatland productivity varies as a function of water table position and surface moisture content, making C storage in these systems particularly vulnerable to the climate warming and drying predicted for high latitudes. Detailed spatial knowledge of how aboveground vegetation communities respond to changes in hydrology would allow for ecosystem response to environmental change to be measured at the landscape scale. This study leverages remotely sensed data along with field measurements taken at the Alaska Peatland Experiment (APEX) at the Bonanza Creek Long Term Ecological Research site to examine relationships between plant solar reflectance and surface moisture. APEX is a decade-long experiment investigating the effects of hydrologic change on peatland ecosystems using water table manipulation treatments (raised, lowered, and control). Water table levels were manipulated throughout the 2015 growing season, resulting in a maximum separation of 35 cm between raised and lowered treatment plots. Water table position, soil moisture content, depth to seasonal ice, soil temperature, photosynthetically active radiation (PAR), CO2 and CH4 fluxes were measured as predictors of C loss through decomposition and NPP. Vegetation was surveyed for percent cover of plant functional types. Remote sensing data was collected during peak growing season, when the separation between treatment plots was at maximum difference. Imagery was acquired via a SenseFly eBee airborne platform equipped with a Canon S110 red-edge camera capable of detecting spectral reflectance from plant tissue at 715 nm band center to within centimeters of spatial resolution. Here, we investigate empirical relationships between spectral reflectance, water table position, and surface moisture in relation to peat carbon balance.

  1. Delivering a lab experience to students in remote road-less locations in Alaska

    NASA Astrophysics Data System (ADS)

    Spencer, Vanessa; Solie, Daniel

    2010-02-01

    Bush Physics is a pilot physics course offered by the University of Alaska, Fairbanks. Taught both as a distance delivery course for rural students and as a traditional course to students in Fairbanks, it is designed to prepare rural (predominantly Alaska Native) students for success in STEM programs. While the lecture portion is successfully distance-delivered using teleconference, delivering the laboratory portion effectively has been more challenging. Bush Physics has been taught twice previously to a total of 24 students who otherwise would not have had access to physics instruction. Methods utilized to help distance education students complete the laboratory credit include mailing equipment kits, emailing pictures and video descriptions, travel to certain villages to do experiments during weekends and utilizing on-site mentors. Past results and feedback have improved the laboratory section for spring 2010. We plan to use testing and student surveys to begin to quantify improvement in student mathematical ability and reasoning. )

  2. Quantification of peatland specific yield: toward a general peatland water storage indicator

    NASA Astrophysics Data System (ADS)

    Bourgault, Marc-André; Larocque, Marie; Garneau, Michelle

    2016-04-01

    Peatlands are water saturated environment that can be connected to rivers and aquifers. This connectivity is in part controlled by peat properties such as hydraulic conductivity (K) and specific yield (SY). For the last twenty years, many studies have quantified these parameters in peatlands, contributing to better understand peatland hydrological functions such as water storage, river base flows, and groundwater recharge. Nonetheless, the understanding of peatland water storage capacity is still very limited both at local and global scale, in part due to the lack of unique and simple method to quantify the spatial variations of these properties. The objective of this project is to 1) develop a new in situ method to quantify vertical specific yield variations and 2) evaluate the use of this method to quantify storage capacity of peatland. Using an approach based on the water table fluctuation (WTF) method, a program was developed in R to quantify vertical variation of SY with depth for the hydrologically active layer of five southern ombrotrophic peatland complexes of the St. Lawrence Lowlands (southern Quebec, Canada). In each peatland, three water table wells (2 cm diameter and 1 m deep) were installed upgradient, mi-gradient, and downgradient. The wells were instrumented to measure water levels every 5 minutes during summer 2014 and 2015. The range of mean annual water table depths varies from 9.4 to 49.3 cm below the peat surface. Near each piezometer, a 1 m long peat core was sampled using a box corer. Each core was divided into 7 x 7 x 7 cm3 peat cubes and analysed using gravitational drainage experiments. In one of the peatland complexes, a 25 x 60 x 40 cm3 peat sample was collected in the upgradient location. Using a tension table, specific storage was measured on this peat sample at 1.0 cm intervals between 0-20 cm and 2.5 cm intervals between 20-36 cm. The WTF method and the gravitational drainage experiments show similar results, confirming the validity

  3. Vascular plants promote ancient peatland carbon loss with climate warming.

    PubMed

    Walker, Tom N; Garnett, Mark H; Ward, Susan E; Oakley, Simon; Bardgett, Richard D; Ostle, Nicholas J

    2016-05-01

    Northern peatlands have accumulated one third of the Earth's soil carbon stock since the last Ice Age. Rapid warming across northern biomes threatens to accelerate rates of peatland ecosystem respiration. Despite compensatory increases in net primary production, greater ecosystem respiration could signal the release of ancient, century- to millennia-old carbon from the peatland organic matter stock. Warming has already been shown to promote ancient peatland carbon release, but, despite the key role of vegetation in carbon dynamics, little is known about how plants influence the source of peatland ecosystem respiration. Here, we address this issue using in situ (14)C measurements of ecosystem respiration on an established peatland warming and vegetation manipulation experiment. Results show that warming of approximately 1 °C promotes respiration of ancient peatland carbon (up to 2100 years old) when dwarf-shrubs or graminoids are present, an effect not observed when only bryophytes are present. We demonstrate that warming likely promotes ancient peatland carbon release via its control over organic inputs from vascular plants. Our findings suggest that dwarf-shrubs and graminoids prime microbial decomposition of previously 'locked-up' organic matter from potentially deep in the peat profile, facilitating liberation of ancient carbon as CO2. Furthermore, such plant-induced peat respiration could contribute up to 40% of ecosystem CO2 emissions. If consistent across other subarctic and arctic ecosystems, this represents a considerable fraction of ecosystem respiration that is currently not acknowledged by global carbon cycle models. Ultimately, greater contribution of ancient carbon to ecosystem respiration may signal the loss of a previously stable peatland carbon pool, creating potential feedbacks to future climate change. PMID:26730448

  4. Rapid Response of Hydrological Loss of DOC to Water Table Drawdown and Warming in Zoige Peatland: Results from a Mesocosm Experiment

    PubMed Central

    Lou, Xue-Dong; Zhai, Sheng-Qiang; Kang, Bing; Hu, Ya-Lin; Hu, Li-Le

    2014-01-01

    A large portion of the global carbon pool is stored in peatlands, which are sensitive to a changing environment conditions. The hydrological loss of dissolved organic carbon (DOC) is believed to play a key role in determining the carbon balance in peatlands. Zoige peatland, the largest peat store in China, is experiencing climatic warming and drying as well as experiencing severe artificial drainage. Using a fully crossed factorial design, we experimentally manipulated temperature and controlled the water tables in large mesocosms containing intact peat monoliths. Specifically, we determined the impact of warming and water table position on the hydrological loss of DOC, the exported amounts, concentrations and qualities of DOC, and the discharge volume in Zoige peatland. Our results revealed that of the water table position had a greater impact on DOC export than the warming treatment, which showed no interactive effects with the water table treatment. Both DOC concentration and discharge volume were significantly increased when water table drawdown, while only the DOC concentration was significantly promoted by warming treatment. Annual DOC export was increased by 69% and 102% when the water table, controlled at 0 cm, was experimentally lowered by −10 cm and −20 cm. Increases in colored and aromatic constituents of DOC (measured by Abs254 nm, SUVA254 nm, Abs400 nm, and SUVA400 nm) were observed under the lower water tables and at the higher peat temperature. Our results provide an indication of the potential impacts of climatic change and anthropogenic drainage on the carbon cycle and/or water storage in a peatland and simultaneously imply the likelihood of potential damage to downstream ecosystems. Furthermore, our results highlight the need for local protection and sustainable development, as well as suggest that more research is required to better understand the impacts of climatic change and artificial disturbances on peatland degradation. PMID:25369065

  5. Decomposition in northern Minnesota peatlands

    SciTech Connect

    Farrish, K.W.

    1985-01-01

    Decomposition in peatlands was investigated in northern Minnesota. Four sites, an ombrotrophic raised bog, an ombrotrophic perched bog and two groundwater minerotrophic fens, were studied. Decomposition rates of peat and paper were estimated using mass-loss techniques. Environmental and substrate factors that were most likely to be responsible for limiting decomposition were monitored. Laboratory incubation experiments complemented the field work. Mass-loss over one year in one of the bogs, ranged from 11 percent in the upper 10 cm of hummocks to 1 percent at 60 to 100 cm depth in hollows. Regression analysis of the data for that bog predicted no mass-loss below 87 cm. Decomposition estimates on an area basis were 2720 and 6460 km/ha yr for the two bogs; 17,000 and 5900 kg/ha yr for the two fens. Environmental factors found to limit decomposition in these peatlands were reducing/anaerobic conditions below the water table and cool peat temperatures. Substrate factors found to limit decomposition were low pH, high content of resistant organics such as lignin, and shortages of available N and K. Greater groundwater influence was found to favor decomposition through raising the pH and perhaps by introducing limited amounts of dissolved oxygen.

  6. The ecology of patterned boreal peatlands of northern Minnesota: A community profile

    SciTech Connect

    Glaser, P.H.

    1987-06-01

    This report reviews the ecological information available for patterned boreal peatlands in northern Minnesota. Although vast areas of Canada and Alaska are covered by boreal forests, they extend southward into the continental United States only in northern Minnesota and to a lesser extent in northern Michigan. In northern Minnesota these peatlands comprise large areas of freshwater wetlands whose unique hydrological characteristics promote the development of patterned vegetation. This publication describes the distribution of peatlands, the physical settings in which they exist, and the processes leading to their development on the landscape. Hydrology, water chemistry, and nutrient cycling in bogs and fens are discussed. The plant communities unique to these types of wetlands, their successional trends, and the animal communities inhabiting them are also described. The profile closes with a summary of past human impacts on peatlands and recommendations for future management.

  7. Methods for assessing the quality of runoff from Minnesota peatlands

    SciTech Connect

    Clausen, J.C.

    1981-01-01

    The quality of runoff from large, undisturbed peatlands in Minnesota is chaaracterized and sampling results from a number of bogs (referred to as a multiple watershed approach) was used to assess the effects of peat mining on the quality of bog runoff. Runoff from 45 natural peatlands and one mined bog was sampled five times in 1979-80 and analyzed for 34 water quality characteristics. Peatland watersheds were classified as bog, transition, or fen, based upon both water quality and watershed characteristics. Alternative classification methods were based on frequency distributions, cluster analysis, discriminant analysis, and principal component analysis results. A multiple watershed approach was used as a basis of drawing inferences regarding the quality of runoff from a representative sample of natural bogs and a mined bog. The multiple watershed technique applied provides an alternative to long-term paired watershed experiments in evaluating the effects of land use activities on the quality of runoff from peatlands in Minnesota.

  8. Carbon Cycling in Northern Peatlands

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2010-11-01

    Northern peatlands span only 3 million square kilometers, about 3% of the terrestrial area of the globe, yet they represent a significant terrestrial sink for carbon dioxide. They are also important emitters of methane, an even more potent greenhouse gas. Despite their substantial role in the global carbon cycle, peatlands are not typically incorporated into global climate models. The AGU Monograph Carbon Cycling in Northern Peatlands, edited by Andrew J. Baird, Lisa R. Belyea, Xavier Comas, A. S. Reeve, and Lee D. Slater, looks at the disproportionate role peatlands play in the global carbon budget. In this interview, Eos talks with Andy Baird, University of Leeds, Leeds, United Kingdom.

  9. Sulfur Speciation in Peat: a Time-zero Signature for the " Spruce and Peatland Responses Under Climate and Environmental Change" Experiment

    NASA Astrophysics Data System (ADS)

    Furman, O.; Toner, B. M.; Sebestyen, S. D.; Kolka, R. K.; Nater, E. A.

    2014-12-01

    As part of the "Spruce and Peatland Responses Under Climate and Environmental Change" (SPRUCE) experiment, we made initial measurements of sulfur speciation in peat. These observations represent a "time-zero" relative to the intended soil warming experiment which begins in 2015. Total sulfur and sulfur speciation were measured in peat cores (solid phase) from nine plots (hollows and hummocks) to a depth of 2 m. Peat samples were packed under nitrogen and frozen in the field immediately after collection. All subsequent sample storage, handling, and processing were conducted under inert gas. Sulfur speciation was measured using bulk sulfur 1s X-ray absorption near edge structure (XANES) spectroscopy at the SXRMB instrument at the Canadian Light Source, Saskatoon, SK, Canada and at the 9-BM instrument, Advanced Photon Source, Argonne National Laboratory, IL, USA. Total sulfur concentrations ranged from 968 to 4077 mg sulfur / kg dry peat. Sulfur content increased with depth from 2 g sulfur / m2 in the 0-10 cm increment to a maximum value of 38 g sulfur / m2 in the 50-60 cm increment. These sulfur loadings produced high quality XANES spectra. The nine cores exhibited reproducible trends with depth in both total sulfur and specific sulfur species; however, variability in sulfur speciation was greatest in the top 40 cm. All sulfur detected within the peat solids was in an organic form. The most abundant sulfur species group was composed of organic mono-sulfide and thiol forms, representing approximately half of the total sulfur at all depths. Sulfonate and ester-sulfate species were 10-15 mol% of sulfur and exhibited low variability with depth. A subsurface maximum in organic di-sulfide was observed in the 20-30 cm depth increment, which is the transition zone between transiently oxidized acrotelm and permanently saturated anaerobic catotelm. Quantification of major sulfur pools is important for the SPRUCE experiment as they are likely to be indicators of changes in the

  10. A comprehensive data acquisition and management system for an ecosystem-scale peatland warming and elevated CO2 experiment

    SciTech Connect

    Krassovski, M. B.; Riggs, J. S.; Hook, L. A.; Nettles, W. R.; Hanson, P. J.; Boden, T. A.

    2015-11-09

    Ecosystem-scale manipulation experiments represent large science investments that require well-designed data acquisition and management systems to provide reliable, accurate information to project participants and third party users. The SPRUCE project (Spruce and Peatland Responses Under Climatic and Environmental Change, http://mnspruce.ornl.gov) is such an experiment funded by the Department of Energy's (DOE), Office of Science, Terrestrial Ecosystem Science (TES) Program. The SPRUCE experimental mission is to assess ecosystem-level biological responses of vulnerable, high carbon terrestrial ecosystems to a range of climate warming manipulations and an elevated CO2 atmosphere. SPRUCE provides a platform for testing mechanisms controlling the vulnerability of organisms, biogeochemical processes, and ecosystems to climatic change (e.g., thresholds for organism decline or mortality, limitations to regeneration, biogeochemical limitations to productivity, and the cycling and release of CO2 and CH4 to the atmosphere). The SPRUCE experiment will generate a wide range of continuous and discrete measurements.

    In order to successfully manage SPRUCE data collection, achieve SPRUCE science objectives, and support broader climate change research, the research staff has designed a flexible data system using proven network technologies and software components. The primary SPRUCE data system components are the following; 1. data acquisition and control system – set of hardware and software to retrieve biological and engineering data from sensors, collect sensor status information, and distribute feedback to control components; 2. data collection system – set of hardware and software to deliver data to a central depository for storage and further processing; and 3. data management plan – set of plans, policies, and practices to control consistency, protect data integrity, and

  11. New approaches to the restoration of shallow marginal peatlands.

    PubMed

    Grand-Clement, E; Anderson, K; Smith, D; Angus, M; Luscombe, D J; Gatis, N; Bray, L S; Brazier, R E

    2015-09-15

    Globally, the historic and recent exploitation of peatlands through management practices such as agricultural reclamation, peat harvesting or forestry, have caused extensive damage to these ecosystems. Their value is now increasingly recognised, and restoration and rehabilitation programmes are underway to improve some of the ecosystem services provided by peatlands: blocking drainage ditches in deep peat has been shown to improve the storage of water, decrease carbon losses in the long-term, and improve biodiversity. However, whilst the restoration process has benefitted from experience and technical advice gained from restoration of deep peatlands, shallow peatlands have received less attention in the literature, despite being extensive in both uplands and lowlands. Using the experience gained from the restoration of the shallow peatlands of Exmoor National Park (UK), and two test catchments in particular, this paper provides technical guidance which can be applied to the restoration of other shallow peatlands worldwide. Experience showed that integrating knowledge of the historical environment at the planning stage of restoration was essential, as it enabled the effective mitigation of any threat to archaeological features and sites. The use of bales, commonly employed in other upland ecosystems, was found to be problematic. Instead, 'leaky dams' or wood and peat combination dams were used, which are both more efficient at reducing and diverting the flow, and longer lasting than bale dams. Finally, an average restoration cost (£306 ha(-1)) for Exmoor, below the median national value across the whole of the UK, demonstrates the cost-effectiveness of these techniques. However, local differences in peat depth and ditch characteristics (i.e. length, depth and width) between sites affect both the feasibility and the cost of restoration. Overall, the restoration of shallow peatlands is shown to be technically viable; this paper provides a template for such process

  12. Moderate drop in water table increases peatland vulnerability to post-fire regime shift

    NASA Astrophysics Data System (ADS)

    Kettridge, N.; Turetsky, M. R.; Sherwood, J. H.; Thompson, D. K.; Miller, C. A.; Benscoter, B. W.; Flannigan, M. D.; Wotton, B. M.; Waddington, J. M.

    2015-01-01

    Northern and tropical peatlands represent a globally significant carbon reserve accumulated over thousands of years of waterlogged conditions. It is unclear whether moderate drying predicted for northern peatlands will stimulate burning and carbon losses as has occurred in their smaller tropical counterparts where the carbon legacy has been destabilized due to severe drainage and deep peat fires. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland subjected to decadal drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands. The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon.

  13. Moderate drop in water table increases peatland vulnerability to post-fire regime shift

    PubMed Central

    Kettridge, N.; Turetsky, M. R.; Sherwood, J. H.; Thompson, D. K.; Miller, C. A.; Benscoter, B. W.; Flannigan, M. D.; Wotton, B. M.; Waddington, J. M.

    2015-01-01

    Northern and tropical peatlands represent a globally significant carbon reserve accumulated over thousands of years of waterlogged conditions. It is unclear whether moderate drying predicted for northern peatlands will stimulate burning and carbon losses as has occurred in their smaller tropical counterparts where the carbon legacy has been destabilized due to severe drainage and deep peat fires. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland subjected to decadal drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands. The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon. PMID:25623290

  14. Moderate drop in water table increases peatland vulnerability to post-fire regime shift.

    PubMed

    Kettridge, N; Turetsky, M R; Sherwood, J H; Thompson, D K; Miller, C A; Benscoter, B W; Flannigan, M D; Wotton, B M; Waddington, J M

    2015-01-01

    Northern and tropical peatlands represent a globally significant carbon reserve accumulated over thousands of years of waterlogged conditions. It is unclear whether moderate drying predicted for northern peatlands will stimulate burning and carbon losses as has occurred in their smaller tropical counterparts where the carbon legacy has been destabilized due to severe drainage and deep peat fires. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland subjected to decadal drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands. The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon. PMID:25623290

  15. Alaska Native Rural Development: The NANA Experience. Occasional Paper No. 2.

    ERIC Educational Resources Information Center

    Gaffney, Michael J.

    Faced with the need to build new social and economic institutions following the 1971 Alaska Native Claims Settlement Act, Alaska Natives formed 12 regional non-profit making corporations. One of these, Northwest Arctic Inupiat (NANA), is bringing a human resources development approach to the area in an effort to develop enduring economic and…

  16. 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.

  17. Zero methane-emitting peatlands: biogeochemical features and forecasting response to environmental change

    NASA Astrophysics Data System (ADS)

    Sirin, Andrey; Suvorov, Gennady; Glagolev, Mikhail; Kravchenko, Irina; Chistotin, Maxim; Bazhin, Nikolai

    2014-05-01

    Peatlands are one of the main sources of atmospheric CH4, a greenhouse gas responsible for a large part of current climate forcing. Existing estimates of methane flux from peatlands on a country, continental and global scale do not cover all variety of extremely diverse natural peatland ecosystems, their spatial uncertainties, and related to human impacts modifications. During last 2-3 decades numerous CH4flux measurements were conducted in northern peatlands, but many peatland types were not elaborated being suggested as unessential or even 'zero' source of methane to the atmosphere. Among them are widespread forested dwarf-shrub sphagnum peatbogs, frozen flat palsa mires, etc., as well as considered 'dry' peatlands drained and utilized for peat extraction, agriculture and forestry. Methane fluxes were measured at key peatland taiga test-plots of Central part of European Russia and taiga and tundra-forest zones of West Siberia purposely to examine periods of different level of humidity. The water level (WL) position switching from methane emission to uptake was elucidated for pine-dwarf-shrub-sphagnum ecotopes: at 50 cm WL near-zero or negative methane fluxes were registered at 86% of measurements, at 40 cm WL - emission at 89%. Observations in Central European Russia cover different natural and drained peatland types. Drainage and management usually decreased CH4 emissions relative to pristine peatlands through drying of surface peats and simultaneous decrease the size of anoxic horizons, but the rise of WL switches to CH4 fluxes. Relation between methane flux and peat wetness was additionally tested by series of lab mesocosm experiments. Processes resulting in similar final zero methane emissions under conditions of drained and intact peatland could be different. Microbial communities, involved in methane cycle, have been significantly changed in drained peatlands. Methanogens in natural peatlands were almost exclusively composed of hydrogenotrophs, whereas both

  18. The effects of hydrologic fluctuation and sulfate regeneration on mercury cycling in an experimental peatland

    NASA Astrophysics Data System (ADS)

    Coleman Wasik, J. K.; Engstrom, D. R.; Mitchell, C. P. J.; Swain, E. B.; Monson, B. A.; Balogh, S. J.; Jeremiason, J. D.; Branfireun, B. A.; Kolka, R. K.; Almendinger, J. E.

    2015-09-01

    A series of severe droughts during the course of a long-term, atmospheric sulfate-deposition experiment in a boreal peatland in northern Minnesota created a unique opportunity to study how methylmercury (MeHg) production responds to drying and rewetting events in peatlands under variable levels of sulfate loading. Peat oxidation during extended dry periods mobilized sulfate, MeHg, and total mercury (HgT) to peatland pore waters during rewetting events. Pore water sulfate concentrations were inversely related to antecedent moisture conditions and proportional to past and current levels of atmospheric sulfate deposition. Severe drying events caused oxidative release of MeHg to pore waters and resulted in increased net MeHg production likely because available sulfate stimulated the activity of sulfate-reducing bacteria, an important group of Hg-methylating bacteria in peatlands. Rewetting events led to increased MeHg concentrations across the peatland, but concentrations were highest in peat receiving elevated atmospheric sulfate deposition. Dissolved HgT concentrations also increased in peatland pore waters following drought but were not affected by sulfate loading and did not appear to be directly controlled by dissolved organic carbon mobilization to peatland pore waters. Peatlands are often considered to be sinks for sulfate and HgT in the landscape and sources of MeHg. Hydrologic fluctuations not only serve to release previously sequestered sulfate and HgT from peatlands but may also increase the strength of peatlands as sources of MeHg to downstream aquatic systems, particularly in regions that have experienced elevated levels of atmospheric sulfate deposition.

  19. The Burning of Surface and Deep Peat during Boreal Forest and Peatland Fires: Implications for Fire Behaviour and Global Carbon Cycling

    NASA Astrophysics Data System (ADS)

    Turetsky, M. R.

    2015-12-01

    Fire is increasingly appreciated as a threat to peatlands and their carbon stocks. The global peatland carbon pool exceeds that of global vegetation and is similar to the current atmospheric carbon pool. Under pristine conditions, most of the peat carbon stock is protected from burning, and resistance to fire has increased peat carbon storage in high latitude regions over long time scales. This, in part, is due to the high porosity and storage coefficient of surface peat, which minimizes water table variability and maintains wet conditions even during drought. However, higher levels of disturbance associated with warming and increasing human activities are triggering state changes and the loss of resiliency in some peatland systems. This presentation will summarize information on burn area and severity in peatlands under undisturbed scenarios of hydrologic self-regulation, and will assess the consequences of warming and drying on peatland vegetation and wildfire behaviour. Our goal is to predict where and when peatlands will become more vulnerable to deep smouldering, given the importance of deep peat layers to global carbon cycling, permafrost stability, and a variety of other ecosystem services in northern regions. Results from two major wildfire seasons (2004 in Alaska and 2014 in the Northwest Territories) show that biomass burning in peatlands releases similar amounts of carbon to the atmosphere as patterns of burning in upland forests, but that peatlands are less vulnerable to severe burning that tends to occur in boreal forests during late season fire activity.

  20. Alaska, Naturally Occurring Asbestos: Experiences, Policy and 2012 Limitation of Liability Legislation

    NASA Astrophysics Data System (ADS)

    Hargesheimer, J.; Perkins, R.

    2012-12-01

    Naturally Occurring Asbestos (NOA) occurs in mineral deposits in Alaska. There are many regions in Alaska that have minerals in surface rocks that may contain asbestos and asbestos has been discovered in many locations in Alaska. Gravel is constantly in demand for heavy construction projects, but some remote localities in Alaska do not have gravel sources that are NOA-free. Determining if NOA can be safely used in heavy construction materials and what can or should be done with NOA materials that are already in place are complex questions. Answers will depend on the amount and type of asbestos mineral, how it is handled in processing, and how it is maintained - all subject to regulation and control of operations. The State of Alaska recently enacted legislation (HB 258) providing, among other things, "… immunity for the state and for landowners, extractors, suppliers, transporters, and contractors for certain actions or claims arising in connection with the use of gravel or aggregate material containing naturally occurring asbestos in certain areas." Implementation of the law and interim regulations and guidance should enable use of NOA for heavy construction materials in Alaska, but as with any new law, it will take some time to understand its full scope and effect.

  1. Modelling Seasonal Carbon Dynamics on Fen Peatlands

    NASA Astrophysics Data System (ADS)

    Giebels, Michael; Beyer, Madlen; Augustin, Jürgen; Roppel, Mario; Juszczak, Radoszlav; Serba, Tomasz

    2010-05-01

    identification of main flux driving parameters. Based on this procedure we developed a specific methane efflux model, mainly driven by the observed groundwater fluctuation and soil temperature. Depending on the observed timescale initial starting points of the model showed up to be remarkably different. We also will present suggestions for an advanced CO2 modelling as the present approaches are both based on single parameters. Generally our experiences from our field studies show that mono-parameterized models often fail in reproducing measured flux values. References: Augustin, J., Merbach, W., Käding, H., Schnidt, W. & Schalitz, G. 1996. Lachgas- und Methanemissionen aus degradierten Niedermoorstandorten Nordostdeutschlands unter dem Einfluß unterschiedlicher Bewirtschaftung. Alfed-Wegener-Stiftung (ed.): Von den Ressourcen zum Recycling: Geoanalytik-Geomanagement-Geoinformatik. Ernst & Sohn Verlag. Berlin Charman, D. 2002: Peatland and environmental change. John Wiley & Sons, LTD, Chichester Droesler, M. 2005. Trace Gas Exchange and climatic relevance of bog ecosystems, Southern Germany, phD-thesis, TU München, München Joosten, H. & Clarke, D. 2002: Wise use of mires and peatlands-background and principles including a framework for decision-making. International Mire Conservation Group and International Peat Society (eds.), Finland Kuntze 1993: Moore als Senken und Quellen für C und N, Mitt. Deutsche Bodenkundliche Gesellschaft 69, 277-280 Lloyd, J., Taylor, J. A. 1994. On the Temperature Dependence of Soil Respiration, Functional Ecology, Vol. 8, No. 3, pp. 315-323 Succow, M. & Joosten, H. 2001: Landschaftsökologische Moorkunde, 2nd edition, Schweizerbart'sche Verlagsbuchhandlung, Stuttgart

  2. Methane flux from Minnesota peatlands

    SciTech Connect

    Crill, P.M.; Bartlett, K.B.; Harriss, R.C.; Gorham, E.; Verry, E.S. )

    1988-12-01

    Northern (> 40 deg N) wetlands have been suggested as the largest natural source of methane (CH{sub 4}) to the troposphere. To refine the authors 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. Late spring and summer fluxes ranged from 11 to 866 mg CH{sub 4}/sq/m/day, averaging 207 mg CH{sub 4} sq/m/day overall. At Marcell Forest, forested bogs and fen sites had lower fluxes than open bogs. 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. Peat temperature was an important control. Methane flux increased in response to increasing soil temperature. It is estimated that the methane flux from all peatlands north of 40 deg 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 CH{sub 4} producing season, and the spatial and temporal variability of the flux. 60 refs., 7 figs., 5 tabs.

  3. Denali Geographic 2012 : A University led scientific field experience for High School students at the Alaska Summer Research Academy

    NASA Astrophysics Data System (ADS)

    Shipman, J. S.; Webley, P. W.; Burke, S.; Chebul, E.; Dempsey, A.; Hastings, H.; Terry, R.; Drake, J.

    2012-12-01

    The Alaska Summer Research Academy (ASRA) annually provides the opportunity for ~150 exceptional high school students to engage in scientific exploration at the university level. In July 2012, University of Alaska Fairbanks instructors led a two-week long ASRA module, called 'Denali Geographic', where eight student participants from across the USA and Canada learned how to observe changes in the natural world and design their own experiments for a field expedition to Denali National Park and Preserve, with assistance from the National Park Service. Each student designed an experiment/observational project prior to the expedition to investigate changes across the expanse of the park. Projects included wildlife documentation; scat and track observations; soil ph and moisture with elevation and vegetation changes; wildflowers species distribution; waterborne insect populations; atmospheric pressure and temperature variations; construction of sustainable buildings to minimize human impact on the park; and park geology comparisons between outcrop and distal stream deposits. The students learned how to design experiments, purchase supplies needed to conduct the work, and select good locations in which to sample in the park. Students used equipment such as GPS to mark field locations; a range finder to determine distance from wildlife; a hygrometer for temperature and pressure; nets and sorting equipments to analyze insects; and the preparation of Plaster of Paris for creating casts of animal tracks. All observations were documented in their field notebooks and blog entries made to share their experiences. Day excursions as part of the module included Poker Flats Research Range, where students learned about the use of unmanned aerial vehicles in scientific exploration; Alaska Volcano Observatory, where students learned about volcanic hazards in Alaska and the North Pacific; Chena Hot Springs and the Ice Museum, where students learned about thermal imaging using a Forward

  4. OIL SPILL BIOREMEDIATION: EXPERIENCES, LESSONS AND RESULTS FROM THE EXXON VALDEZ OIL SPILL IN ALASKA

    EPA Science Inventory

    The use of bioremediation as a supplemental cleanup technology in the Exxon Valdez oil spill, in Prince William Sound, Alaska, has proven to be a good example of the problems and successes associated with the practical application of this technology. ield studies conducted by sci...

  5. Peatland hydrogeological function at the regional scale

    NASA Astrophysics Data System (ADS)

    Larocque, M.; Avard, K.; Pellerin, S.

    2012-12-01

    Peatlands are important components of northern landscapes. In the Canadian province of Quebec, peatlands of the St. Lawrence Valley are rapidly disappearing, threatened by rapidly growing pressures from development. Peatlands are to varying extents groundwater dependent and as such are likely to respond drastically to changes in groundwater flow conditions and to contribute to the maintenance of groundwater levels within a superficial aquifer. Yet, there is very little understanding of the hydrogeological function of peatlands at the regional scale. For this reason, they are often simply discarded in complex groundwater management decisions. The implications are not clearly understood but could lead to the disruption of ecologically important fluxes and to significant impacts for the maintenance of long term water reservoirs across the land. This study was initiated in the Centre-du-Quebec region of southern Quebec to quantify how the peatland landscape has evolved in the last decades and to understand the hydrogeological function of peatlands at the regional scale. The study area (2856 km2) is located in the St. Lawrence Lowlands. The last deglaciation has contributed to a complex stratigraphy of unconsolidated sediments and peatlands have developed at the foot of the Appalachians. A recent regional study of Quaternary deposits has shown that a majority of these peatlands are found on aeolian deposits or reworked till, while only a few are set on marine clay, littoral deposits or directly on the bedrock. The area occupied by peatlands was measured with aerial photographs dating from 1966 and 2010. In 2010, peatlands were found on 6.1 % of the territory. Of these peatlands, 10 485 ha were intact and 7 015 underwent limited perturbations (e.g. drainage ditch, forest roads). Between 1966 and 2010, nearly a quarter of the peatlands observed in 1966 underwent irreversible perturbations (e.g. agriculture, paved roads). The main cause of peatland disappearance was from

  6. The Utility of Fire Radiative Energy for Understanding Fuel Consumption due to Wildfire in Boreal Peatlands

    NASA Astrophysics Data System (ADS)

    Banskota, A.; Falkowski, M. J.; Kane, E. S.; Smith, A. M.

    2014-12-01

    Radiative energy from active fire has been found to correlate well with the amount of fuel consumed during the lifetime of a fire event. Fire radiative power (FRP) detected by sensors onboard MODIS satellites may therefore provide direct estimates of CO2 emissions related to biomass burning. Less known is the ability of satellite data to detect active fire from predominantly smoldering burns in boreal peatlands. Boreal peatlands store a large amount of soil carbon that is likely to become increasingly vulnerable to wildfire as climate change lowers water tables and exposes C-rich peat to burning. In this study, we investigate the utility of fire radiative energy (FRE) to estimate fuel consumption associated with wildfire in 2004 in boreal peatlands in Alaska. FRE values are generally estimated from FRP retrieved at detected active fire locations and times by summing the FRP values multiplied by the time difference between acquisitions. One central issue in deriving reliable FRE estimates by such approach is the requirement for sufficient sampling of the FRP to capture spatiotemporal variability in the fire. Our preliminary analysis confirms that the detection of active fire in peatlands are indeed not spatially exhaustive and temporally continuous. Thus we are further investigating the fusion of instantaneous FRP from MODIS active fire detection with the MODIS burned area product to derive FRE estimates across the burned area. We are following a previously tested strategy for such fusion for temporal integration of instantaneous FRP to derive FRE and spatial extrapolation of FRE over the burned area. The FRE estimates are then related to ground-measured peatland burn depths across different wildfire locations. The results of this study will ultimately indicate the utility of MODIS fire products for providing reliable biomass burned estimates in boreal peatlands.

  7. Gulf of Alaska, Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This MODIS true-color image shows the Gulf of Alaska and Kodiak Island, the partially snow-covered island in roughly the center of the image. Credit: Jacques Descloitres, MODIS Land Rapid Response Team

  8. 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

  9. Representing northern peatland microtopography and hydrology within the Community Land Model

    NASA Astrophysics Data System (ADS)

    Shi, X.; Thornton, P. E.; Ricciuto, D. M.; Hanson, P. J.; Mao, J.; Sebestyen, S. D.; Griffiths, N. A.; Bisht, G.

    2015-11-01

    Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth for a vegetated wetland, independent of prescribed regional water tables. We introduce here a new configuration of the Community Land Model (CLM) which includes a fully prognostic water table calculation for a vegetated peatland. Our structural and process changes to CLM focus on modifications needed to represent the hydrologic cycle of bogs environment with perched water tables, as well as distinct hydrologic dynamics and vegetation communities of the raised hummock and sunken hollow microtopography characteristic of peatland bogs. The modified model was parameterized and independently evaluated against observations from an ombrotrophic raised-dome bog in northern Minnesota (S1-Bog), the site for the Spruce and Peatland Responses Under Climatic and Environmental Change experiment (SPRUCE). Simulated water table levels compared well with site-level observations. The new model predicts hydrologic changes in response to planned warming at the SPRUCE site. At present, standing water is commonly observed in bog hollows after large rainfall events during the growing season, but simulations suggest a sharp decrease in water table levels due to increased evapotranspiration under the most extreme warming level, nearly eliminating the occurrence of standing water in the growing season. Simulated soil energy balance was strongly influenced by reduced winter snowpack under warming simulations, with the warming influence on soil temperature partly offset by the loss of insulating snowpack in early and late winter. The new model provides improved predictive capacity for seasonal hydrological dynamics in northern

  10. Representing northern peatland microtopography and hydrology within the Community Land Model

    DOE PAGESBeta

    Shi, Xiaoying; Thornton, Peter E.; Ricciuto, Daniel M.; Hanson, Paul J.; Mao, Jiafu; Sebestyen, Stephen D.; Griffiths, Natalie A.; Bisht, Gautam

    2015-11-12

    Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth for a vegetated wetland, independent of prescribed regional water tables. We introduce here a new configuration of the Community Land Model (CLM) which includes a fully prognostic water table calculation for a vegetated peatland. Our structural and process changes to CLM focus on modifications needed to representmore » the hydrologic cycle of bogs environment with perched water tables, as well as distinct hydrologic dynamics and vegetation communities of the raised hummock and sunken hollow microtopography characteristic of peatland bogs. The modified model was parameterized and independently evaluated against observations from an ombrotrophic raised-dome bog in northern Minnesota (S1-Bog), the site for the Spruce and Peatland Responses Under Climatic and Environmental Change experiment (SPRUCE). Simulated water table levels compared well with site-level observations. The new model predicts hydrologic changes in response to planned warming at the SPRUCE site. At present, standing water is commonly observed in bog hollows after large rainfall events during the growing season, but simulations suggest a sharp decrease in water table levels due to increased evapotranspiration under the most extreme warming level, nearly eliminating the occurrence of standing water in the growing season. Simulated soil energy balance was strongly influenced by reduced winter snowpack under warming simulations, with the warming influence on soil temperature partly offset by the loss of insulating snowpack in early and late winter. Furthermore, the new model provides improved predictive capacity for seasonal hydrological

  11. Representing northern peatland microtopography and hydrology within the Community Land Model

    NASA Astrophysics Data System (ADS)

    Shi, X.; Thornton, P. E.; Ricciuto, D. M.; Hanson, P. J.; Mao, J.; Sebestyen, S. D.; Griffiths, N. A.; Bisht, G.

    2015-02-01

    Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth for a vegetated wetland, independent of prescribed regional water tables. We introduce here a new configuration of the Community Land Model (CLM) which includes a fully prognostic water table calculation for a vegetated peatland. Our structural and process changes to CLM focus on modifications needed to represent the hydrologic cycle of bogs environment with perched water tables, as well as distinct hydrologic dynamics and vegetation communities of the raised hummock and sunken hollow microtopography characteristic of peatland bogs. The modified model was parameterized and independently evaluated against observations from an ombrotrophic raised-dome bog in northern Minnesota (S1-Bog), the site for the Spruce and Peatland Responses Under Climatic and Environmental Change experiment (SPRUCE). Simulated water table levels compared well with site-level observations. The new model predicts significant hydrologic changes in response to planned warming at the SPRUCE site. At present, standing water is commonly observed in bog hollows after large rainfall events during the growing season, but simulations suggest a sharp decrease in water table levels due to increased evapotranspiration under the most extreme warming level, nearly eliminating the occurrence of standing water in the growing season. Simulated soil energy balance was strongly influenced by reduced winter snowpack under warming simulations, with the warming influence on soil temperature partly offset by the loss of insulating snowpack in early and late winter. The new model provides improved predictive capacity for seasonal hydrological dynamics

  12. Representing northern peatland microtopography and hydrology within the Community Land Model

    SciTech Connect

    Shi, Xiaoying; Thornton, Peter E.; Ricciuto, Daniel M.; Hanson, Paul J.; Mao, Jiafu; Sebestyen, Stephen D.; Griffiths, Natalie A.; Bisht, Gautam

    2015-11-12

    Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth for a vegetated wetland, independent of prescribed regional water tables. We introduce here a new configuration of the Community Land Model (CLM) which includes a fully prognostic water table calculation for a vegetated peatland. Our structural and process changes to CLM focus on modifications needed to represent the hydrologic cycle of bogs environment with perched water tables, as well as distinct hydrologic dynamics and vegetation communities of the raised hummock and sunken hollow microtopography characteristic of peatland bogs. The modified model was parameterized and independently evaluated against observations from an ombrotrophic raised-dome bog in northern Minnesota (S1-Bog), the site for the Spruce and Peatland Responses Under Climatic and Environmental Change experiment (SPRUCE). Simulated water table levels compared well with site-level observations. The new model predicts hydrologic changes in response to planned warming at the SPRUCE site. At present, standing water is commonly observed in bog hollows after large rainfall events during the growing season, but simulations suggest a sharp decrease in water table levels due to increased evapotranspiration under the most extreme warming level, nearly eliminating the occurrence of standing water in the growing season. Simulated soil energy balance was strongly influenced by reduced winter snowpack under warming simulations, with the warming influence on soil temperature partly offset by the loss of insulating snowpack in early and late winter. Furthermore, the new model provides improved predictive capacity for seasonal hydrological dynamics

  13. Representing northern peatland microtopography and hydrology within the Community Land Model

    SciTech Connect

    Shi, X.; Thornton, P. E.; Ricciuto, D. M.; Hanson, P. J.; Mao, J.; Sebestyen, S. D.; Griffiths, N. A.; Bisht, G.

    2015-02-20

    Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth for a vegetated wetland, independent of prescribed regional water tables. We introduce here a new configuration of the Community Land Model (CLM) which includes a fully prognostic water table calculation for a vegetated peatland. Our structural and process changes to CLM focus on modifications needed to represent the hydrologic cycle of bogs environment with perched water tables, as well as distinct hydrologic dynamics and vegetation communities of the raised hummock and sunken hollow microtopography characteristic of peatland bogs. The modified model was parameterized and independently evaluated against observations from an ombrotrophic raised-dome bog in northern Minnesota (S1-Bog), the site for the Spruce and Peatland Responses Under Climatic and Environmental Change experiment (SPRUCE). Simulated water table levels compared well with site-level observations. The new model predicts significant hydrologic changes in response to planned warming at the SPRUCE site. At present, standing water is commonly observed in bog hollows after large rainfall events during the growing season, but simulations suggest a sharp decrease in water table levels due to increased evapotranspiration under the most extreme warming level, nearly eliminating the occurrence of standing water in the growing season. Simulated soil energy balance was strongly influenced by reduced winter snowpack under warming simulations, with the warming influence on soil temperature partly offset by the loss of insulating snowpack in early and late winter. The new model provides improved predictive capacity for seasonal hydrological dynamics

  14. Representing northern peatland microtopography and hydrology within the Community Land Model

    DOE PAGESBeta

    Shi, X.; Thornton, P. E.; Ricciuto, D. M.; Hanson, P. J.; Mao, J.; Sebestyen, S. D.; Griffiths, N. A.; Bisht, G.

    2015-02-20

    Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth for a vegetated wetland, independent of prescribed regional water tables. We introduce here a new configuration of the Community Land Model (CLM) which includes a fully prognostic water table calculation for a vegetated peatland. Our structural and process changes to CLM focus on modifications needed to representmore » the hydrologic cycle of bogs environment with perched water tables, as well as distinct hydrologic dynamics and vegetation communities of the raised hummock and sunken hollow microtopography characteristic of peatland bogs. The modified model was parameterized and independently evaluated against observations from an ombrotrophic raised-dome bog in northern Minnesota (S1-Bog), the site for the Spruce and Peatland Responses Under Climatic and Environmental Change experiment (SPRUCE). Simulated water table levels compared well with site-level observations. The new model predicts significant hydrologic changes in response to planned warming at the SPRUCE site. At present, standing water is commonly observed in bog hollows after large rainfall events during the growing season, but simulations suggest a sharp decrease in water table levels due to increased evapotranspiration under the most extreme warming level, nearly eliminating the occurrence of standing water in the growing season. Simulated soil energy balance was strongly influenced by reduced winter snowpack under warming simulations, with the warming influence on soil temperature partly offset by the loss of insulating snowpack in early and late winter. The new model provides improved predictive capacity for seasonal hydrological

  15. Peatland-GHG emissions in Europe

    NASA Astrophysics Data System (ADS)

    Droesler, Matthias

    2013-04-01

    Managed peatlands are hot spots for CO2, CH4 and N2O emissions. GHG which have been not fully integrated in past European climate projects. Peatlands contribute to European GHG emissions 10 times more per unit area than other terrestrial ecosystems. Peatland management and exploration by drainage, agricultural use and peat extraction turned pristine peatland GHG sinks into sources. Emissions can reach more than 40 t CO2equiv. ha-1 a-1 in intensively managed peatlands. On the other hand, the restoration of degraded peatlands does normally reduce these emissions significantly towards climate neutral levels, once the restoration work is done wisely. But in some cases the net climate effect do not decrease significantly depending on hydrological regimes, fertilization status of the peatlands, climate and vegetation type. In many European countries with significant peatland cover nationally funded projects were set up to investigate peatland GHG fluxes and their drivers. These scattered data and knowledge are currently being brought together under the coverage of the GHG-Europe project (Grant agreement no.: 244122) within a new synthesis to develop the relevant EF, identify the drivers and develop upscaling options for GHG-emissions. The talk will: (1) show a first cut of new Emission Factors for peatlands in Europe and compare these with IPCC-default values. (2) discuss the developed sensible response functions for GHG-fluxes against natural and anthropogenic drivers such as land use intensity, land management with drainage and climate variability. (3) show case studies from Germany show the applicability of response functions for upscaling of GHG-balances. (4) An outlook is given to the future European peatland GHG-Balance.

  16. Trade-Offs in Resource Allocation Among Moss Species Control Decomposition in Boreal Peatlands

    SciTech Connect

    Turetsky, M. R.; Crow, S. E.; Evans, R. J.; Vitt, D. H.; Wieder, R. K.

    2008-01-01

    We separated the effects of plant species controls on decomposition rates from environmental controls in northern peatlands using a full factorial, reciprocal transplant experiment of eight dominant bryophytes in four distinct peatland types in boreal Alberta, Canada. Standard fractionation techniques as well as compound-specific pyrolysis molecular beam mass spectrometry were used to identify a biochemical mechanism underlying any interspecific differences in decomposition rates. We found that over a 3-year field incubation, individual moss species and not micro-environmental conditions controlled early stages of decomposition. Across species, Sphagnum mosses exhibited a trade-off in resource partitioning into metabolic and structural carbohydrates, a pattern that served as a strong predictor of litter decomposition. Decomposition rates showed a negative co-variation between species and their microtopographic position, as species that live in hummocks decomposed slowly but hummock microhabitats themselves corresponded to rapid decomposition rates. By forming litter that degrades slowly, hummock mosses appear to promote the maintenance of macropore structure in surface peat hummocks that aid in water retention. Many northern regions are experiencing rapid climate warming that is expected to accelerate the decomposition of large soil carbon pools stored within peatlands. However, our results suggest that some common peatland moss species form tissue that resists decomposition across a range of peatland environments, suggesting that moss resource allocation could stabilize peatland carbon losses under a changing climate.

  17. Upscaling microtopography in high-latitude peatlands

    NASA Astrophysics Data System (ADS)

    Cresto Aleina, F.; Runkle, B. R.; Kleinen, T.; Kutzbach, L.; Boike, J.; Brovkin, V.

    2013-12-01

    A challenging problem in climate modeling is how to deal with interactions and feedbacks across a multiplicity of spatial scales, and how to improve our understanding of the role played by local soil heterogeneities in the climate system. This is of particular interest in northern peatlands, because of the large amount of carbon stored in the soil. Greenhouse gas (GHG) fluxes, such as methane, carbon dioxide and water vapor, vary largely within the environment, as an effect of the small scale processes that characterize the landscape. It is then essential to consider the local heterogeneous behavior of the system components in order to properly estimate water and carbon balances. We propose a novel method to fill the scaling gap from local mechanistic models to large scale mean field approximations. We developed a surface model for peatlands working at the landscape scale, which is able to show the impact of surface microtopography in modeling greenhouse gas fluxes. We tuned our landscape-scale model with data from a peatland site in the Komi Republic of Russia. We simulate surface microtopography and hydrology, and we couple it to a process-based model for methane emissions from the soil (Walter and Heiman, 1996). By partitioning the space in smaller subunits and then analyzing the statistical properties of the tiling, we are able to resolve the small scale processes and investigate their effects at larger scales. We not only investigate the influence of the hummocky surface on GHG emissions, but we are also able to simulate how complex hydrological interactions happening within the system at a subgrid scale affect the landscape-scale land-atmosphere GHG fluxes. We force our model climatology with data from the CMIP5 experiments. Future projections use forcing from the RCP 8.5 scenario, in order to investigate the impact of microrelieves on the future carbon cycle. We also explore potential dynamical feedbacks with the atmospheric water cycle and energy balance by

  18. 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.

  19. Analyzing peatland discharge to streams in an Alaskan watershed: An integration of end-member mixing analysis and a water balance approach

    NASA Astrophysics Data System (ADS)

    Gracz, Michael B.; Moffett, Mary F.; Siegel, Donald I.; Glaser, Paul H.

    2015-11-01

    Peatlands are the dominant landscape element in many northern watersheds where they can have an important influence on the hydrology of streams. However, the capacity of peatlands to moderate stream flow during critical dry periods remains uncertain partly due to the difficulty of estimating discharge from extensive peat deposits. We therefore used two different approaches to quantify diffuse pore water contributions from peatlands to a creek within a small watershed in Southcentral Alaska. A sensitivity analysis of a water budget for a representative peatland within this watershed showed that a substantial surplus of pore water may remain available for subsequent discharge during a dry period after accounting for water losses to evapotranspiration. These findings were supported by end member mixing analysis (EMMA), which indicated that 55% of the stream flow during a dry period originated from the near-surface layers of peatlands within the watershed. Contributions from peatlands to stream flow in northern coastal regions may therefore provide an important buffer against the potentially harmful effects of changing climatic conditions on commercially important fish species.

  20. Water repellency diminishes peatland evaporation after wildfire

    NASA Astrophysics Data System (ADS)

    Kettridge, N.; Lukenbach, M.; Hokanson, K. J.; Devito, K. J.; Petrone, R. M.; Hopkinson, C.; Waddington, J. M.

    2015-12-01

    Peatlands are a critically important global carbon reserve. There is increasing concern that such ecosystems are vulnerable to projected increases in wildfire severity under a changing climate. Severe fires may exceed peatland ecological resilience resulting in the long term degradation of this carbon store. Evaporation provides the primary mechanisms of water loss from such environments and can regulate the ecological stress in the initial years after wildfire. We examine variations in evaporation within burned peatlands after wildfire through small scale chamber and large scale remote sensing measurements. We show that near-surface water repellency limits peatland evaporation in these initial years post fire. Water repellent peat produced by the fire restricts the supply of water to the surface, reducing evaporation and providing a strong negative feedback to disturbance. This previously unidentified feedback operates at the landscape scale. High surface temperatures that result from large reductions in evaporation within water repellent peat are observed across the 60,000 ha burn scar three months after the wildfire. This large scale reduction in evaporation promotes high water table positions at a landscape scale which limits the rate of peat decomposition and supports the post fire ecohydrological recovery of the peatlands. However, severe burns are shown to exceed this negative feedback response. Deep burns at the peatland margins remove the hydrophobic layer, increasing post fire evaporation and leaving the peatland vulnerable to drying and associated ecological shifts.

  1. Water repellency diminishes peatland evaporation after wildfire

    NASA Astrophysics Data System (ADS)

    Kettridge, Nick; Lukenbach, Max; Hokanson, Kelly; Devito, Kevin; Hopkinson, Chris; Petrone, Rich; Mendoza, Carl; Waddington, Mike

    2016-04-01

    Peatlands are a critically important global carbon reserve. There is increasing concern that such ecosystems are vulnerable to projected increases in wildfire severity under a changing climate. Severe fires may exceed peatland ecological resilience resulting in the long term degradation of this carbon store. Evaporation provides the primary mechanisms of water loss from such environments and can regulate the ecological stress in the initial years after wildfire. We examine variations in evaporation within burned peatlands after wildfire through small scale chamber and large scale remote sensing measurements. We show that near-surface water repellency limits peatland evaporation in these initial years post fire. Water repellent peat produced by the fire restricts the supply of water to the surface, reducing evaporation and providing a strong negative feedback to disturbance. This previously unidentified feedback operates at the landscape scale. High surface temperatures that result from large reductions in evaporation within water repellent peat are observed across the 60,000 ha burn scar three months after the wildfire. This promotes high water table positions at a landscape scale which limit the rate of peat decomposition and supports the post fire ecohydrological recovery of the peatlands. However, severe burns are shown to exceed this negative feedback response. Deep burns at the peatland margins remove the hydrophobic layer, increasing post fire evaporation and leaving the peatland vulnerable to drying and associated ecological shifts.

  2. Methane emissions from a peatland following restoration

    NASA Astrophysics Data System (ADS)

    Waddington, J. M.; Day, S. M.

    2007-09-01

    Peatland drainage and peat extraction changes natural peatlands from a net carbon sink to that of a large net source due to increased respiration and the removal of carbon dioxide (CO2) fixing vegetation. Restoration of these altered peatland ecosystems is being applied to reduce these carbon emissions. As peatland restoration is a new and emerging land-use management practice, the purpose of this research was to examine the impact of restoration on the methane (CH4) component of the carbon cycle at the Bois-des-Bel peatland located near Rivière-du-Loup, Québec from early May to mid October for several years. The seasonal CH4 fluxes prior to restoration at an extracted (cutover) and a restored peatland were not significantly different from each other or zero. However, three years postrestoration the seasonal CH4 emissions at the restored site were 4.2 g m-2 CH4 season-1, 4.6 times greater than the cutover site. Ponds and ditches at the restored site were seasonal CH4 emission hot spots (0.3 and 2.9 g m-2 CH4 season-1, respectively); however, emissions from herbaceous vegetation (1.0 g m-2 CH4 season-1) were the dominant source of CH4 from the restored peatland due to its large areal extent. CH4 fluxes from the Bois-des-Bel peatland represented 14% of the total CO2-equivalent losses from the site. This study demonstrates the importance of vegetation succession on peatland-atmosphere flux of CH4.

  3. Experimental sulfate amendment alters peatland bacterial community structure.

    PubMed

    Strickman, R J S; Fulthorpe, R R; Coleman Wasik, J K; Engstrom, D R; Mitchell, C P J

    2016-10-01

    As part of a long-term, peatland-scale sulfate addition experiment, the impact of varying sulfate deposition on bacterial community responses was assessed using 16S tag encoded pyrosequencing. In three separate areas of the peatland, sulfate manipulations included an eight year quadrupling of atmospheric sulfate deposition (experimental), a 3-year recovery to background deposition following 5years of elevated deposition (recovery), and a control area. Peat concentrations of methylmercury (MeHg), a bioaccumulative neurotoxin, were measured, the production of which is attributable to a growing list of microorganisms, including many sulfate-reducing Deltaproteobacteria. The total bacterial and Deltaproteobacterial community structures in the experimental treatment differed significantly from those in the control and recovery treatments that were either indistinguishable or very similar to one another. Notably, the relatively rapid return (within three years) of bacterial community structure in the recovery treatment to a state similar to the control, demonstrates significant resilience of the peatland bacterial community to changes in atmospheric sulfate deposition. Changes in MeHg accumulation between sulfate treatments correlated with changes in the Deltaproteobacterial community, suggesting that sulfate may affect MeHg production through changes in the community structure of this group. PMID:27267720

  4. Dual controls on carbon loss during drought in peatlands

    NASA Astrophysics Data System (ADS)

    Wang, Hongjun; Richardson, Curtis J.; Ho, Mengchi

    2015-06-01

    Peatlands store one-third of global soil carbon. Drought/drainage coupled with climate warming present the main threat to these stores. Hence, understanding drought effects and inherent feedbacks related to peat decomposition has been a primary global challenge. However, widely divergent results concerning drought in recent studies challenge the accepted paradigm that waterlogging and associated anoxia are the overarching controls locking up carbon stored in peat. Here, by linking field and microcosm experiments, we show how previously unrecognized mechanisms regulate the build-up of phenolics, which protects stored carbon directly by reducing phenol oxidase activity during short-term drought and, indirectly, through a shift from low-phenolic Sphagnum/herbs to high-phenolic shrubs after long-term moderate drought. We demonstrate that shrub expansion induced by drought/warming in boreal peatlands might be a long-term self-adaptive mechanism not only increasing carbon sequestration but also potentially protecting historic soil carbon. We therefore propose that the projected `positive feedback loop’ between carbon emission and drought in peatlands may not occur in the long term.

  5. Alaska's Secondary Science Teachers and Students Receive Earth Systems Science Knowledge, GIS Know How and University Technical Support for Pre- College Research Experiences: The EDGE Project

    NASA Astrophysics Data System (ADS)

    Connor, C. L.; Prakash, A.

    2007-12-01

    Alaska's secondary school teachers are increasingly required to provide Earth systems science (ESS) education that integrates student observations of local natural processes related to rapid climate change with geospatial datasets and satellite imagery using Geographic Information Systems (GIS) technology. Such skills are also valued in various employment sectors of the state where job opportunities requiring Earth science and GIS training are increasing. University of Alaska's EDGE (Experiential Discoveries in Geoscience Education) program has provided training and classroom resources for 3 cohorts of inservice Alaska science and math teachers in GIS and Earth Systems Science (2005-2007). Summer workshops include geologic field experiences, GIS instruction, computer equipment and technical support for groups of Alaska high school (HS) and middle school (MS) science teachers each June and their students in August. Since 2005, EDGE has increased Alaska science and math teachers' Earth science content knowledge and developed their GIS and computer skills. In addition, EDGE has guided teachers using a follow-up, fall online course that provided more extensive ESS knowledge linked with classroom standards and provided course content that was directly transferable into their MS and HS science classrooms. EDGE teachers were mentored by University faculty and technical staff as they guided their own students through semester-scale, science fair style projects using geospatial data that was student- collected. EDGE program assessment indicates that all teachers have improved their ESS knowledge, GIS knowledge, and the use of technology in their classrooms. More than 230 middle school students have learned GIS, from EDGE teachers and 50 EDGE secondary students have conducted original research related to landscape change and its impacts on their own communities. Longer-term EDGE goals include improving student performance on the newly implemented (spring 2008) 10th grade

  6. The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) FTS: Results From the 2012/13 Alaska Campaigns

    NASA Astrophysics Data System (ADS)

    Kurosu, Thomas P.; Miller, Charles E.; Dinardo, Stephen J.

    2014-05-01

    The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) is an aircraft-based Earth Venture 1 mission to study the carbon balance of the Alaskan Arctic ecosystem, with a particular focus on carbon release from melting permafrost. Operating from its base in Fairbanks, AK, the CARVE aircraft covers a range of principle flight paths in the Alaskan interior, the Yukon River valley, and the northern Alaska coast around Barrow and Dead Horse. Flight paths are chosen to maximize ecosystem variability and cover burn-recovery/regrowth sequences. CARVE observations cover the Arctic Spring/Summer/Fall seasons, with multiple flights per season and principle flight path. Science operations started in May 2012 and are currently envisaged to continue until 2015. The CARVE suite of instruments includes flask measurements, in situ gas analyzers for CO2, CH4 and CO observations, and a three-band polarizing Fourier Transform Spectrometer (FTS) for column measurements of CO2, CH4, CO, their interfering species (e.g., H2O), and O2. The FTS covers the spectral regions of 4,200-4,900 cm-1, 5,800-6,400 cm-1, and 12,900-13,200 cm-1, with a spectral resolution of 0.2 cm-1. Aircraft-based FTS science observations in Alaska have been performed since 23-05-2012. First-version data products from all CARVE instruments derived from observations during the 2012 campaign were publicly released earlier in 2013. The FTS has performed well during flight conditions, particularly with respect to vibration damping. Outstanding challenges include the need for improved spectral and radiometric calibration, as well as compensating for low signal-to-noise spectra acquired under Alaskan flight conditions. We present results from FTS column observations of CO2, CH4, and CO, observed during the 2012 and 2013 campaigns, including preliminary comparisons of CARVE FTS measurements with satellite observations of CO2 from TANSO/GOSAT and CO from MOPITT.

  7. Methane Production in Minnesota Peatlands

    PubMed Central

    Williams, Richard T.; Crawford, Ronald L.

    1984-01-01

    Rates of methane production in Minnesota peats were studied. Surface (10- to 25-cm) peats produced an average of 228 nmol of CH4 per g (dry weight) per h at 25°C and ambient pH. Methanogenesis rates generally decreased with depth in ombrotrophic peats, but on occasion were observed to rise within deeper layers of certain fen peats. Methane production was temperature dependent, increasing with increasing temperature (4 to 30°C), except in peats from deeper layers. Maximal methanogenesis from these deeper regions occurred at 12°C. Methane production rates were also pH dependent. Two peats with pHs of 3.8 and 4.3 had an optimum rate of methane production at pH 6.0. The addition to peat of glucose and H2-CO2 stimulated methanogenesis, whereas the addition of acetate inhibited methanogenesis. Cysteine-sulfide, nitrogen-phosphorus-trace metals, and vitamins-yeast extract affected methane production very little. Various gases were found to be trapped or dissolved (or both) within peatland waters. Dissolved methane increased linearly to a depth of 210 cm. The accumulation of metabolic end products produced within peat bogs appears to be an important mechanism limiting carbon turnover in peatland environments. PMID:16346565

  8. Methane production in Minnesota peatlands

    SciTech Connect

    Williams, R.T.; Crawford, R.L.

    1984-06-01

    Rates of methane production in Minnesota peats were studied. Surface (10- to 25-cm) peats produced an average of 228 nmol of CH/sub 4/ per g (dry weight) per h at 25/sup 0/C and ambient pH. Methanogenesis rates generally decreased with depth in ombrotrophic peats, but on occasion were observed to rise within deeper layers of certain fen peats. Methane production was temperature dependent, increasing with increasing temperature (4 to 30/sup 0/C), except in peats from deeper layers. Maximal methanogenesis from these deeper regions occurred at 12/sup 0/C. Methane production rates were also pH dependent. Two peats with pHs of 3.8 and 4.3 had an optimum rate of methane production at pH 6.0. The addition to peat of glucose and H/sub 2/-CO/sub 2/ stimulated methanogenesis, whereas the addition of acetate inhibited methanogenesis. Cysteine-sulfide, nitrogen-phosphorus-trace metals, and vitamins-yeast extract affected methane production very little. Various gases were found to be trapped or dissolved (or both) within peatland waters. Dissolved methane increased linearly to a depth of 210 cm. The accumulation of metabolic end products produced within peat bogs appears to be an important mechanism limiting turnover in peatland environments.

  9. Effects of artificial-recharge experiments at Ship Creek alluvial fan on water levels at Spring Acres Subdivision, Anchorage, Alaska

    USGS Publications Warehouse

    Meyer, William; Patrick, Leslie

    1980-01-01

    The effect of the artificial recharge experiments on water levels at Spring Acres subdivision, Anchorage, Alaska, was evaluated using two digital models constructed to simulate groundwater movement and water-level rises induced by the artificial recharge. The models predicted that the artificial recharge would have caused water levels in the aquifer immediately underlying Spring Acres subdivision to rise 0.2 foot from May 20 to August 7, 1975. The models also predicted a total rise in groundwater levels of 1.1 feet at this location from July 16, 1973 to August 7, 1975, as a result of the artificial-recharge experiments. Water-level data collected from auger holes in March 1975 by a consulting firm for the contractor indicated a depth to water of 6-7 feet below land surface at Spring Acres subdivision at this time. Water levels measured in and near Spring Acres subdivision several years before and after the 1973-75 artificial-recharge experiments showed seasonal rises of 2 to 12.4 feet. A depth to water below land surface of 2.6 feet was measured 600 feet from the subdivision in 1971 and in the subdivision in 1977. Average measured depth to water in the area was 7.0 feet from early 1976 to September 1979. (USGS)

  10. Health Care and Satellite Radio Communication in Village Alaska. Final Report of the ATS-1 Biomedical Satellite: Experiment Evaluation.

    ERIC Educational Resources Information Center

    Kreimer, Osvaldo; And Others

    The executive summary is the first section of this final report of the evaluation of the ATS-1 medical communication system in Alaska. The second section introduces the background of these studies and the sociogeographic setting and health situation of the Alaska natives. The third section presents the main research findings about both the…

  11. Artificial recharge experiments on the Ship Creek alluvial fan, Anchorage, Alaska

    USGS Publications Warehouse

    Anderson, Gary S.

    1977-01-01

    During the summers of 1973 and 174, water from Ship Creek, Alaska, was diverted at an average rate of approximately 6 cfs (cubic feet per second) to an 11-acre recharge basin. Maximum sustained unit recharge for the basin was approximately 1.4 feet per day. During 1975 a second basin of 8 acres was also used for recharge, and the total diversion rate was increased to as much as 30 cfs. The second basin was never completely filled, but the unit recharge rate was at least four times as great as that in the first basin. During 1973 and 1974, when only one recharge basin was in operation, a maximum rise of 18 feet was observed in the ground-water table near the basin. In 1975, when both basins were being used, the maximum rise was 30 feet in the same area. During 1973 and 1974, the water-level rise was 12 and 8 feet in the unconfined and confined systems, respectively, at a point 4,400 feet downgradient from the basins; in 1975 the rise at the same point was 31 and 16 feet, respectively. The potentiometric rise that was achieved in the confined aquifer during summer operation of the recharge basins was quickly dissipated when diversion stopped and the basins drained. Thus the benefits of recharge would not persist into late winter, the critical period for water availability in Anchorage, unless diversion to the basins could be continued until January or February. (Woodard-USGS)

  12. Peatland carbon cycling and the implications of permafrost thaw; a chronosequence study.

    NASA Astrophysics Data System (ADS)

    Olefeldt, D.; Pelletier, N.; Talbot, J.; Blodau, C.; Turetsky, M. R.

    2015-12-01

    Peatlands in the Mackenzie River valley initiated ~9000 years ago and have built up vast soil carbon stores since. Peatland development history in this region is characterized by several distinct stages, varying in nutrient status and permafrost conditions. Widespread permafrost thaw has recently occurred in response to warming, thus making large soil C stores available for microbial processes and mineralization. A crucial question to answer is whether these peatland become net sinks or sources of C following thaw. The net response to thaw will either be dominated by new peat C accumulation at the surface or by mineralization of old peat C released from permafrost. In order to address this question we cored peat plateaus and nearby thermokarst bogs near Fort Simpson, Northwest Territories, representing 4 chronosequences. The cores were analyzed for C content, radiocarbon dates, macrofossils, testate amoebas, peat humification degree, elemental analysis, and microbial lability through an incubation experiment. Together, these approaches reveal peatland development histories, both before and following permafrost thaw. It is clear from our findings that C cycling following permafrost thaw will be intrinsically dependent on the developmental history of the peatland.

  13. Representing Northern Peatland Hydrology and Biogeochemistry within the Community Land Model

    NASA Astrophysics Data System (ADS)

    Shi, X.; Ricciuto, D. M.; Xu, X.; Thornton, P. E.; Hanson, P. J.; Mao, J.; Sebestyen, S.; Griffiths, N.

    2015-12-01

    Northern peatlands are projected to become very important in future carbon-climate feedback due to their large carbon storage and vulnerability to changes in hydrology and climate impacts. Understanding the hydrology and biogeochemistry is a fundamental task for projecting the fate of massive carbon stores in these systems under future climate change. Models have started to address microtopographic controls on peatland hydrology, but none have considered a prognostic calculation of water table dynamics in vegetated peatlands rather than prescribed regional water tables. We introduced here a new configuration of the Community Land Model (CLM), which includes a fully prognostic water table calculation between hummock and hollow microtopography in a vegetated peatland. We further integrated the hydrology treatment with vertically structured soil organic matter pools, and a newly developed microbial functional group-based methane module. The model was further used to test against observational data obtained within Spruce and Peatland Responses Under Climatic and Environmental Change (SPRUCE) project. Results for water table dynamic, carbon profile, and land surface fluxes of carbon dioxide and methane were reasonable. Model simulations showed that warming and elevated CO2 had significant impacts on land surface fluxes of methane and carbon dioxide. The warming-induced hydrological changes are another factors influencing biogeochemistry along soil profiles and land surface gas fluxes. These preliminary results provide some insights for field experiments as well as data-model comparison in next phase of the SPRUCE project.

  14. Partitioning Belowground Respiration in a Northern Peatland

    NASA Astrophysics Data System (ADS)

    Stewart, H. E.; Roulet, N. T.; Moore, T.

    2004-05-01

    Although they cover only 3% of the land surface, northern peatlands store up to one-third of the global soil carbon pool, deeming them a significant carbon sink. However, changes in peatland soil respiration could lead to peatlands becoming carbon sources with consequent feedbacks to climate change. In order to understand the global carbon balance we need to understand respiration processes, but compared to photosynthesis we know very little about respiration, especially belowground. Within soils there are three compartments among which carbon is transferred and respired: roots, rhizosphere and root-free soil. In order to further the understanding of respiration processes of northern peatlands, the relative importance of each type of belowground respiration was determined at two locations at Mer Bleue, a northern peatland located near Ottawa, Ontario. Weekly CO2 flux measurements, using dark chambers and a portable IRGA, were made throughout the growing season of 2003. At both areas there are reference plots to determine total respiration where the vegetation remained in tact. Treatment plots were also installed at both areas where foliage was removed in order to determine SOM (shrub-free) respiration. The shrub foliage was replaced with nylon `foliage' in an attempt to maintain soil temperature and moisture conditions. Root respiration was determined by incubating root segments on-site, taking air samples over a one hour period. Rhizosphere respiration was estimated by subtracting SOM, root and aboveground respiration from total respiration, and aboveground respiration was removed from the equation using a calculation from a peatland carbon model.

  15. Effect of water level drawdown on decomposition in boreal peatlands

    NASA Astrophysics Data System (ADS)

    Straková, Petra; Penttilä, Timo; Laiho, Raija

    2010-05-01

    Plant litter production and decomposition are key processes in element cycling in most ecosystems. In peatlands, there has been a long-term imbalance between litter production and decay caused by high water levels (WL) and consequent anoxia. This has resulted in peatlands being a significant sink of carbon (C) from the atmosphere. However, peatlands are experiencing both "natural" (global climate change) and anthropogenic (ditching) changes that threaten their ability to retain this ecosystem identity and function. Many of these alterations can be traced back to WL drawdown, which can cause increased aeration, higher acidity, falling temperatures, and a greater probability of drought. Such changes are also associated with an increasing decomposition rate, and therefore a greater amount of C released back to the atmosphere. Yet studies about how the overall C balance of peatlands will be affected have come up with conflicting conclusions, demonstrating that the C store could increase, decrease, or remain static. A factor that has been largely overlooked is the change in litter type composition following persistent WL drawdown. It is the aim of our study, then, to help to resolve this issue. We studied the effects of short-term (ca. 4 years) and long-term (ca. 40 years) persistent WL drawdown on the decomposition of numerous types of above-ground and below-ground plant litters at three boreal peatland sites: bog, oligotrophic fen and mesotrophic fen. We thus believe that enough permutations have been created to obtain a good assessment of how each factor, site nutrient level, WL regime, and litter type composition, influences decomposition. We used the litter bag method to measure the decomposition rates: placed measured amounts of plant litter, or cellulose strips as a control, into closed mesh bags, and installed the bags in the natural environment for decomposition for each litter type for varying amounts of time. Following litter bag recovery, the litter was

  16. A comparative study of within-basin and regional peatland development: implications for peatland carbon dynamics

    NASA Astrophysics Data System (ADS)

    Ireland, Alex W.; Booth, Robert K.; Hotchkiss, Sara C.; Schmitz, Jennifer E.

    2013-02-01

    Northern peatlands are among the most carbon-rich ecosystems on Earth, but many unanswered questions remain regarding linkages between their long-term developmental processes and climatic variability. In this paper, we present a detailed paleoecological reconstruction of the developmental history of a kettle peatland in northern Wisconsin, USA (Fallison Bog) based on 21 coring locations and temporally constrained by 69 radiocarbon dates. This record of within-basin developmental history is compared to a regional dataset containing estimated ages of peatland establishment for 75 core samples collected from 37 depressional peatlands throughout the Great Lakes Region. Finally, our data are used to develop a spatially explicit model of whole-system carbon accumulation in Fallison Bog, which distinguishes between carbon pools stored in limnic sediments and peat deposits. Results indicate that peatland development in Fallison Bog was episodic and spatially complex. Peatland development was related to the morphology of the underlying basin and characterized by pulses of both terrestrialization and paludification. Major episodes of terrestrialization centered on 4980 and 3180 years before A.D. 1850 (cal yr BP), with less extensive episodes occurring around 3840, 1060, 670, and 410 cal yr BP. Extensive peatland area developed by paludification of shallow portions of the basin around 2040 cal yr BP. The timing of peatland development within Fallison Bog was correlated with the timing of peatland development in other depressional peatlands across the Great Lakes Region (r = 0.70), suggesting a common climatic driver. Comparison of peatland development in Fallison Bog and independent paleoclimate records suggested that both millennial-scale and sub-centennial-scale variability in moisture balance influenced spatiotemporal patterns of peatland development. Model results indicated that Fallison Bog accumulated ˜6655 t of carbon during the Holocene, with 66% of this total stored

  17. [Nitrogen input altered testate amoebae community in peatland of Sanjiang Plain, Northeast China].

    PubMed

    Song, Li-hong; Yan, Xiu-min; Wang, Ke-hong; Zhu, Xiao-yan; Wu, Dong-hu

    2015-02-01

    In the present study, an in situ control experiment was carried out to explore the response of testate amoebae to exogenous nitrogen addition in peatland of Sanjiang Plain. The results showed that nitrogen addition increased the biomass of testate amoebae at lower levels (6 g N · m(-2)), while decreased it at higher levels (> 12 g N · m(-2)). At genus level, nitrogen addition significantly increased the biomass of Arcella and Phryganella, decreased the biomass of Euglypha. Only lower nitrogen addition significantly increased the biomass of Centropyxis. At species level, nitrogen addition significantly decreased the biomass of Euglypha rotunda, while the biomass of either Centropyxis cassis or Phryganella acropodia was increased by a lower nitrogen addition treatment. This study suggested that the response of peatland testate amoebae to nitrogen addition was species specific, which could potentially be used as an indicator for the environment of peatlands. PMID:26094475

  18. Predicting soil respiration from peatlands.

    PubMed

    Rowson, J G; Worrall, F; Evans, M G; Dixon, S D

    2013-01-01

    This study considers the relative performance of six different models to predict soil respiration from upland peat. Predicting soil respiration is important for global carbon budgets and gap filling measured data from eddy covariance and closed chamber measurements. Further to models previously published new models are presented using two sub-soil zones and season. Models are tested using data from the Bleaklow plateau, southern Pennines, UK. Presented literature models include ANOVA using logged environmental data, the Arrhenius equation, modified versions of the Arrhenius equation to include soil respiration activation energy and water table depth. New models are proposed including the introduction of two soil zones in the peat profile, and season. The first new model proposes a zone of high CO(2) productivity related to increased soil microbial CO(2) production due to the supply of labile carbon from plant root exudates and root respiration. The second zone is a deeper zone where CO(2) production is lower with less labile carbon. A final model allows the zone of high CO(2) production to become dormant during winter months when plants will senesce and will vary depending upon vegetation type within a fixed location. The final model accounted for, on average, 31.9% of variance in net ecosystem respiration within 11 different restoration sites whilst, using the same data set, the best fitting literature equation only accounted for 18.7% of the total variance. Our results demonstrate that soil respiration models can be improved by explicitly accounting for seasonality and the vertically stratified nature of soil processes. These improved models provide an enhanced basis for calculating the peatland carbon budgets which are essential in understanding the role of peatlands in the global C cycle. PMID:23178842

  19. Recovery and archiving key Arctic Alaska vegetation map and plot data for the Arctic-Boreal Vulnerability Field Experiment (ABoVE)

    NASA Astrophysics Data System (ADS)

    Walker, D. A.; Breen, A. L.; Broderson, D.; Epstein, H. E.; Fisher, W.; Grunblatt, J.; Heinrichs, T.; Raynolds, M. K.; Walker, M. D.; Wirth, L.

    2013-12-01

    Abundant ground-based information will be needed to inform remote-sensing and modeling studies of NASA's Arctic-Boreal Vulnerability Experiment (ABoVE). A large body of plot and map data collected by the Alaska Geobotany Center (AGC) and collaborators from the Arctic regions of Alaska and the circumpolar Arctic over the past several decades is being archived and made accessible to scientists and the public via the Geographic Information Network of Alaska's (GINA's) 'Catalog' display and portal system. We are building two main types of data archives: Vegetation Plot Archive: For the plot information we use a Turboveg database to construct the Alaska portion of the international Arctic Vegetation Archive (AVA) http://www.geobotany.uaf.edu/ava/. High quality plot data and non-digital legacy datasets in danger of being lost have highest priority for entry into the archive. A key aspect of the database is the PanArctic Species List (PASL-1), developed specifically for the AVA to provide a standard of species nomenclature for the entire Arctic biome. A wide variety of reports, documents, and ancillary data are linked to each plot's geographic location. Geoecological Map Archive: This database includes maps and remote sensing products and links to other relevant data associated with the maps, mainly those produced by the Alaska Geobotany Center. Map data include GIS shape files of vegetation, land-cover, soils, landforms and other categorical variables and digital raster data of elevation, multispectral satellite-derived data, and data products and metadata associated with these. The map archive will contain all the information that is currently in the hierarchical Toolik-Arctic Geobotanical Atlas (T-AGA) in Alaska http://www.arcticatlas.org, plus several additions that are in the process of development and will be combined with GINA's already substantial holdings of spatial data from northern Alaska. The Geoecological Atlas Portal uses GINA's Catalog tool to develop a

  20. Altered peat hydrophysical properties following drainage and wildfire increases peatland vulnerability to ecosystem regime shift

    NASA Astrophysics Data System (ADS)

    Waddington, James; Kettridge, Nick; Sherwood, James; Granath, Gustaf

    2015-04-01

    Northern peatlands represent a globally significant carbon reservoir, composed largely of legacy carbon which is no longer part of the active carbon cycle. However, it is unclear whether this legacy carbon is vulnerable as a result of enhanced peat smouldering and combustion under the moderate drying conditions predicted for northern peatlands as a result of climate change and/or disturbance from forestry, mining, and associated transport development. A significant loss in legacy carbon as a result of wildfire has already been observed in smaller tropical peatlands where deep peat soils have been destabilized due to severe drainage and a shift in vegetation. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland several decades post drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition, previously observed within only severely disturbed tropical peatlands, when accompanied by wildfire. The combined impact of moderate drainage followed by wildfire resulted in a shift of the peat surface down the peat profile, exposing denser peat at the surface. In undisturbed northern peatlands where depth of burn is typically low, low-density near-surface peats help regulate water-table position and near-surface moisture availability post-fire, both of which are favourable to Sphagnum recolonization. As a result of drainage and fire at the study site, the self-regulating properties of the low-density Sphagnum surface were lost. We demonstrate that changes in peat hydrophysical properties increased hydrological limitations to Sphagnum recovery leading to the conversion to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy carbon stored in the peat.

  1. Holocene peatland initiation in the Greater Everglades

    NASA Astrophysics Data System (ADS)

    Dekker, Stefan C.; Boer, Hugo J.; Dermody, Brian J.; Wagner-Cremer, Friederike; Wassen, Martin J.; Eppinga, Maarten B.

    2015-02-01

    The mechanisms involved in the initiation and development of the Greater Everglades peatland ecosystems remain a topic of discussion. In this study, we first present an overview of basal ages of peat deposits in South Florida, which shows two major episodes of peatland initiation between 7.0-4.5 kyr and 3.5-2.0 kyr. Our analysis of regional climate proxy data sets led to three alternative hypotheses that may explain the timing and duration of these two peatland initiation episodes: (1) decreased drainage due to relative sea level (RSL) rise during the Holocene, (2) gradual increase in precipitation throughout the Holocene, and (3) a combination of increasing precipitation, rising RSL, and oscillations in the climate system. We test whether these three hypotheses can explain the pattern of initiation and development of the Greater Everglades peatlands using models that simulate the nonlinear processes involved in peat production and decomposition. The model results suggest that RSL rise could explain the onset of peatland initiation and imply that the climate was wet enough for peat development also during the early Holocene. The first two hypothesized mechanisms in combination with climate oscillations may explain the onset of peat accumulation at 8.2 kyr B.P. The two-phased character of peatland initiation maybe explained by the spatial distribution of local drainage conditions. As peatland development is highly nonlinear, our model uncovers a mechanistic way how peats can suddenly shift from a dry high equilibrium to a wet low equilibrium resulting in lake formation as observed in paleoecological studies in the Greater Everglades.

  2. Carbon dynamics in peatland pool systems: the role of light

    NASA Astrophysics Data System (ADS)

    Pickard, Amy; Heal, Kate; McLeod, Andy; Dinsmore, Kerry

    2016-04-01

    Open-water pools are widespread in peatlands and are considered to represent biogeochemical hotspots within the peatland landscape. However the contribution of pool systems to wider peatland C cycling has not been quantified fully and there is a lack of knowledge of the role of photochemical processes in such environments. In this study, light exposure experiments were conducted in two contrasting pools to test the reactivity of aquatic C. The first study site was located at Cross Lochs (CL), Forsinard, in the Flow Country of Northern Scotland, in a 412 m2 pool characterised by low dissolved organic carbon (DOC) concentrations (˜15 mg C L‑1). The second site was located at Red Moss of Balerno (RM), a raised bog in central Scotland, in a 48 m2 pool with high DOC concentrations (˜35 mg C L‑1). Experiments took place over 9 days in situ at each pool in mid-summer 2015, with 500 mL water samples contained in bags transparent to sunlight and in opaque control bags. After field exposure, optical, chemical and stable C isotope analyses were conducted on the samples. Significant differences in biogeochemical cycling of DOC were detected between the two systems, with DOC losses as a percentage of the total C pool 15% higher at RM than at CL after light exposure. The mean DOC concentration of light exposed samples at RM declined steeply initially, with 83% observed DOC degradation occurring by day 3 of the experiment. Total losses of 7.9 mg DOC L‑1were observed in light exposed samples at RM, along with decreasing E4:E6 ratios, suggesting that material remaining at the end of the experiment was humified. Depletion of DOC was positively correlated with production of CO2 at both sites, with concentrations of up to 4.3 mg CO2-C L‑1 recorded at RM. Stable C isotope signatures at both sites were altered under light treatment, as demonstrated by the production of enriched δ13C-DOC (+0.46 ‰ relative to opaque bags) and depleted δ13C-DIC (-0.97 ‰ relative to opaque

  3. UNIT, ALASKA.

    ERIC Educational Resources Information Center

    Louisiana Arts and Science Center, Baton Rouge.

    THE UNIT DESCRIBED IN THIS BOOKLET DEALS WITH THE GEOGRAPHY OF ALASKA. THE UNIT IS PRESENTED IN OUTLINE FORM. THE FIRST SECTION DEALS PRINCIPALLY WITH THE PHYSICAL GEOGRAPHY OF ALASKA. DISCUSSED ARE (1) THE SIZE, (2) THE MAJOR LAND REGIONS, (3) THE MOUNTAINS, VOLCANOES, GLACIERS, AND RIVERS, (4) THE NATURAL RESOURCES, AND (5) THE CLIMATE. THE…

  4. Carbon isotopes as indicators of peatland growth?

    NASA Astrophysics Data System (ADS)

    Alewell, Christine; Krüger, Jan Paul; von Sengbusch, Pascal; Szidat, Sönke; Leifeld, Jens

    2016-04-01

    As undisturbed and/or growing peatlands store considerable amounts of carbon and are unique in their biodiversity and species assemblage, the knowledge of the current status of peatlands (growing with carbon sequestration, stagnating or degrading with carbon emissions) is crucial for landscape management and nature conservation. However, monitoring of peatland status requires long term measurements and is only feasible with expert knowledge. The latter determination is increasingly impeded in a scientific world, where taxonomic expert knowledge and funding of long term monitoring is rare. Stable carbon and nitrogen isotopes depth profiles in peatland soils have been shown to be a useful tool to monitor the degradation of peatlands due to permafrost thawing in Northern Sweden (Alewell et al., 2011; Krüger et al., 2014), drainage in Southern Finland (Krüger et al., 2016) as well as land use intensification in Northern Germany (Krüger et al., 2015). Here, we tackle the questions if we are able to differentiate between growing and degrading peats with the use of a combination of carbon stable (δ13C) and radiogenic isotope data (14C) with peat stratification information (degree of humification and macroscopic plant remains). Results indicate that isotope data are a useful tool to approximate peatland status, but that expert taxonomic knowledge will be needed for the final conclusion on peatland growth. Thus, isotope tools might be used for landscape screening to pin point sites for detailed taxonomic monitoring. As the method remains qualitative future research at these sites will need to integrate quantitative approaches to determine carbon loss or gain (soil C balances by ash content or C accumulation methods by radiocarbon data; Krüger et al., 2016). Alewell, C., R. Giesler, J. Klaminder, J. Leifeld, and M. Rollog. 2011. Stable carbon isotopes as indicators for micro-geomorphic changes in palsa peats. Biogeosciences, 8, 1769-1778. Krüger, J. P., Leifeld, J

  5. Amphibole reaction rim textures and mineralogy from the 2006 eruption of Augustine Volcano, Alaska: Nature vs. experiment

    NASA Astrophysics Data System (ADS)

    Henton, S.; Larsen, J. F.; Coombs, M. L.

    2011-12-01

    Augustine Volcano forms a small island located in Alaska's Cook Inlet, approximately 180 miles southwest of Anchorage. The 2006 eruption began January 11, 2006, and evolved from an initial phase of explosive activity, through continuous and effusive phases, ending approximately mid-March 2006. We present data on the textural and mineralogical make-up of amphibole reaction rims from 2006 andesites from Augustine. Naturally formed reaction rims are compared to rims formed through decompression and heating experiments. Amphiboles make up less than 1 modal % of most samples. However, variations in composition and texture help to explain pre-and syn-eruptive magma histories. The Augustine 2006 amphiboles contain a mixture of rimmed and unrimmed grains. In order of decreasing abundance (by tally), the dominant phases in reaction rims are orthopyroxene, oxides, plagioclase, and clinopyroxene. Most amphibole reaction rims are between 1- 40 microns in thickness. Thicker rims (> 40 microns) were primarily erupted in the later effusive phase of the eruption. In general, the thickest reactions rims (> 60 microns average thickness) contain coarser individual reaction rim grains (with feret diameters of 15-50 microns). Reaction rims with average thickness of less than 60 microns tend to contain finer reaction rim grains (with feret diameters of 10 microns or less). Some reactions rims show a coarsening of rim grains across the rim, from the amphibole boundary to the glass boundary. Preliminary results show no systematic changes in the aspect ratios of reaction rim grains, either across the rim, or between the different rims. Some rims show a decrease in the An content of plagioclase across the rim, from the amphibole boundary to the glass boundary. Reaction rim textures and mineralogy are complex and suggest that multiple forcing factors (including heating and decompression) were responsible for their formation. This study will compare these natural reaction rims to those formed

  6. Multidisciplinary approach to identify aquifer-peatland connectivity

    NASA Astrophysics Data System (ADS)

    Larocque, Marie; Pellerin, Stéphanie; Cloutier, Vincent; Ferlatte, Miryane; Munger, Julie; Quillet, Anne; Paniconi, Claudio

    2015-04-01

    In southern Quebec (Canada), wetlands sustain increasing pressures from agriculture, urban development, and peat exploitation. To protect both groundwater and ecosystems, it is important to be able to identify how, where, and to what extent shallow aquifers and wetlands are connected. This study focuses on peatlands which are especially abundant in Quebec. The objective of this research was to better understand aquifer-peatland connectivity and to identify easily measured indicators of this connectivity. Geomorphology, hydrogeochemistry, and vegetation were selected as key indicators of connectivity. Twelve peatland transects were instrumented and monitored in the Abitibi (slope peatlands associated with eskers) and Centre-du-Quebec (depression peatlands) regions of Quebec (Canada). Geomorphology, geology, water levels, water chemistry, and vegetation species were identified/measured on all transects. Flow conditions were simulated numerically on two typical transects. Results show that a majority of peatland transects receives groundwater from a shallow aquifer. In slope peatlands, groundwater flows through the organic deposits towards the peatland center. In depression peatlands, groundwater flows only 100-200 m within the peatland before being redirected through surface routes towards the outlet. Flow modeling and sensitivity analysis have identified that the thickness and hydraulic conductivity of permeable deposits close to the peatland and beneath the organic deposits influence flow directions within the peatland. Geochemical data have confirmed the usefulness of total dissolved solids (TDS) exceeding 14 mg/L as an indicator of the presence of groundwater within the peatland. Vegetation surveys have allowed the identification of species and groups of species that occur mostly when groundwater is present, for instance Carex limosa and Sphagnum russowii. Geomorphological conditions (slope or depression peatland), TDS, and vegetation can be measured

  7. (Model) Peatlands in late Quaternary interglacials

    NASA Astrophysics Data System (ADS)

    Kleinen, Thomas; Brovkin, Victor

    2016-04-01

    Peatlands have accumulated a substantial amount of carbon, roughly 600 PgC, during the Holocene. Prior to the Holocene, there is relatively little direct evidence of peatlands, though coal deposits bear witness to a long history of peat-forming ecosystems going back to the Carboniferous. We therefore need to rely on models to investigate peatlands in times prior to the Holocene. We have developed a dynamical model of wetland extent and peat accumulation, integrated in the coupled climate carbon cycle model of intermediate complexity CLIMBER2-LPJ, in order to mechanistically model interglacial carbon cycle dynamics. This model consists of the climate model of intermediate complexity CLIMBER2 and the dynamic global vegetation model LPJ, which we have extended with modules to determine peatland extent and carbon accumulation. The model compares reasonably well to Holocene peat data. We have used this model to investigate the dynamics of atmospheric CO2 in the Holocene and two other late Quaternary interglacials, namely the Eemian, which is interesting due to its warmth, and Marine Isotope Stage 11 (MIS11), which is the longest interglacial during the last 500ka. We will also present model results of peatland extent and carbon accumulation for these interglacials. We will discuss model shortcomings and knowledge gaps currently preventing an application of the model to full glacial-interglacial cycles.

  8. Holocene Carbon Accumulation and Soil Properties in Northern Peatlands: A Circum-Arctic Synthesis (Invited)

    NASA Astrophysics Data System (ADS)

    Loisel, J.; Beilman, D.; Yu, Z.; Camill, P.

    2013-12-01

    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 peatland C-sink capacity and modifying peat-C fluxes to the atmosphere. Yet, the sign and magnitude of the peatland carbon-climate feedback remain uncertain and difficult to assess because of (1) limited understanding of peatland responses to climate change, (2) data gaps and large uncertainties in regional peatland C stocks, and (3) non-linear peatland responses to external forcing. Here we present results from a comprehensive compilation of peat soil properties and Holocene C data for northern peatlands. Our compiled database consists of >250 peat cores from > 200 sites located north of 45N. This synthesis is novel in that our C accumulation estimates are based on directly measured bulk density and C content values. It also encompasses regions within which peat-C data have only recently become available, such as the West Siberia Lowlands, Hudson Bay Lowlands and Kamchatka. Our averaged bulk density value of 0.13 g cm-3 (n = 17,319) is about 16% higher than Gorham's (1991, Ecol. Appl.) widely used estimate of 0.112 g cm-3 for northern peatlands, and 30% larger than the generic value of 0.10 g cm-3 used in recent synthesis (Yu et al. 2009, AGU Monograph 184). When combined with our mean C content value of 48% (n = 2431), these differences in bulk density have important implications for estimating the total C stocks in northern peatlands. Soil organic carbon density (SOC) ranged from 12 to 334 kg C m-2, with a mean value of 102 kg C m-2. A regression model revealed a significant, positive correlation between peat depths and SOC (R2 = 0.675, p < 0.0001), such that higher SOC densities characterized deeper sites. Comparing these values with those published in soil-C surveys that only account for

  9. Alaska Education Experiment. Final Report. Volume II, Appendices A Through E.

    ERIC Educational Resources Information Center

    Alaska Governor's Office of Telecommunications, Juneau.

    This is the second volume of the three volume final report for the Health/Education Telecommunications Experiment. This appendix is a collection of documents which further elucidate the planning and construction of the communications facility. It includes a chronology of funding and contracting events, and copies of the actual grants and contracts…

  10. The Structure and Function of Peatlands in the Hudson Bay Lowlands - Comparing a Pristine and a Hydrologically Impacted Peatland Site

    NASA Astrophysics Data System (ADS)

    Harris, L. I.; Roulet, N. T.; Moore, T. R.

    2014-12-01

    Climate change is considered to pose a significant risk to the vast and varied peatlands of the Hudson Bay Lowlands (HBL). Changes in peatland biogeochemical processes in this region could have major consequences for global greenhouse gas exchange and climate regulation, and yet there are still many gaps and uncertainties in our knowledge of these processes. In particular, our understanding of the mechanisms controlling the structure (vegetation and water table) and function (carbon flux) of these systems is limited. Various theories and models of peatland development have been proposed, including those that describe peatlands as self-regulating systems where long-term stability is maintained by feedback between biological and hydrological processes. There is limited field data however to support the different development theories and to validate proposed feedback mechanisms. Understanding how peatlands are controlled by internal and external forces is also particularly important when considering possible ecosystem shifts due to climate change. Here we compare data from a pristine peatland and a drained peatland site in the HBL to understand peatland structure and function in current climate conditions and a future climate scenario (drier conditions). We measured carbon dioxide and methane fluxes using closed chambers at 51 collar locations (12 collars at the hydrologically impacted site, 39 collars at the pristine peatland site - triplicates at both study sites) representing a total of 13 vegetation communities and different peatland microforms (hummocks, ridges, hollows and pools). Continuous hydrological measurements and vegetation surveys were also completed. These results suggest that peatland structure and function in the HBL must be explained by a combination of peatland development mechanisms and that these mechanisms are dependent on the variable hydroecological setting of peatland areas. We suggest that the drained peatland site may represent an

  11. Bacterial production in subarctic peatland lakes enriched by thawing permafrost

    NASA Astrophysics Data System (ADS)

    Deshpande, Bethany N.; Crevecoeur, Sophie; Matveev, Alex; Vincent, Warwick F.

    2016-08-01

    Peatlands extend over vast areas of the northern landscape. Within some of these areas, lakes and ponds are changing in size as a result of permafrost thawing and erosion, resulting in mobilization of the carbon-rich peatland soils. Our aims in the present study were to characterize the particle, carbon and nutrient regime of a set of thermokarst (thaw) lakes and their adjacent peatland permafrost soils in a rapidly degrading landscape in subarctic Québec, Canada, and by way of fluorescence microscopy, flow cytometry, production measurements and an in situ enrichment experiment, determine the bacterial characteristics of these waters relative to other thaw lakes and rock-basin lakes in the region. The soil active layer in a degrading palsa (peatland permafrost mound) adjacent to one of the lakes contained an elevated carbon content (51 % of dry weight), high C : N ratios (17 : 1 by mass), and large stocks of other elements including N (3 % of dry weight), Fe (0.6 %), S (0.5 %), Ca (0.5 %) and P (0.05 %). Two permafrost cores were obtained to a depth of 2.77 m in the palsa, and computerized tomography scans of the cores confirmed that they contained high concentrations (> 80 %) of ice. Upon thawing, the cores released nitrate and dissolved organic carbon (from all core depths sampled), and soluble reactive phosphorus (from bottom depths), at concentrations well above those in the adjacent lake waters. The active layer soil showed a range of particle sizes with a peak at 229 µm, and this was similar to the distribution of particles in the upper permafrost cores. The particle spectrum for the lake water overlapped with those for the soil, but extended to larger (surface water) or finer (bottom water) particles. On average, more than 50 % of the bacterial cells and bacterial production was associated with particles > 3 µm. This relatively low contribution of free-living cells (operationally defined as the < 1 µm fraction) to bacterial production was a general

  12. Adverse Childhood Experiences among American Indian/Alaska Native Children: The 2011-2012 National Survey of Children's Health.

    PubMed

    Kenney, Mary Kay; Singh, Gopal K

    2016-01-01

    We examined parent-reported adverse childhood experiences (ACEs) and associated outcomes among American Indian and Alaska Native (AI/AN) children aged 0-17 years from the 2011-2012 National Survey of Children's Health. Bivariate and multivariable analyses of cross-sectional data on 1,453 AI/AN children and 61,381 non-Hispanic White (NHW) children assessed race-based differences in ACEs prevalence and differences in provider-diagnosed chronic emotional and developmental conditions, health characteristics, reported child behaviors, and health services received as a function of having multiple ACEs. AI/AN children were more likely to have experienced 2+ ACEs (40.3% versus 21%), 3+ ACEs (26.8% versus 11.5%), 4+ ACEs (16.8% versus 6.2%), and 5+ ACEs (9.9% versus 3.3%) compared to NHW children. Prevalence rates for depression, anxiety, and ADHD were higher among AI/AN children with 3+ ACEs (14.4%, 7.7%, and 12.5%) compared to AI/ANs with fewer than 2 ACEs (0.4%, 1.8%, and 5.5%). School problems, grade failures, and need for medication and counseling were 2-3 times higher among AI/ANs with 3+ ACEs versus the same comparison group. Adjusted odds ratio for emotional, developmental, and behavioral difficulties among AI/AN children with 2+ ACEs was 10.3 (95% CI = 3.6-29.3). Race-based differences were largely accounted for by social and economic-related factors. PMID:27529052

  13. Adverse Childhood Experiences among American Indian/Alaska Native Children: The 2011-2012 National Survey of Children's Health

    PubMed Central

    2016-01-01

    We examined parent-reported adverse childhood experiences (ACEs) and associated outcomes among American Indian and Alaska Native (AI/AN) children aged 0–17 years from the 2011-2012 National Survey of Children's Health. Bivariate and multivariable analyses of cross-sectional data on 1,453 AI/AN children and 61,381 non-Hispanic White (NHW) children assessed race-based differences in ACEs prevalence and differences in provider-diagnosed chronic emotional and developmental conditions, health characteristics, reported child behaviors, and health services received as a function of having multiple ACEs. AI/AN children were more likely to have experienced 2+ ACEs (40.3% versus 21%), 3+ ACEs (26.8% versus 11.5%), 4+ ACEs (16.8% versus 6.2%), and 5+ ACEs (9.9% versus 3.3%) compared to NHW children. Prevalence rates for depression, anxiety, and ADHD were higher among AI/AN children with 3+ ACEs (14.4%, 7.7%, and 12.5%) compared to AI/ANs with fewer than 2 ACEs (0.4%, 1.8%, and 5.5%). School problems, grade failures, and need for medication and counseling were 2-3 times higher among AI/ANs with 3+ ACEs versus the same comparison group. Adjusted odds ratio for emotional, developmental, and behavioral difficulties among AI/AN children with 2+ ACEs was 10.3 (95% CI = 3.6–29.3). Race-based differences were largely accounted for by social and economic-related factors. PMID:27529052

  14. Peatland Structural Controls on Spring Distribution

    NASA Astrophysics Data System (ADS)

    Hare, D. K.; Boutt, D. F.; Hackman, A. M.; Davenport, G.

    2013-12-01

    The species richness of wetland ecosystems' are sustained by the presence of discrete groundwater discharge, or springs. Springs provide thermal refugia and a source of fresh water inflow crucial for survival of many wetland species. The subsurface drivers that control the spatial distribution of surficial springs throughout peatland complexes are poorly understood due to the many challenges peatlands pose for hydrologic characterization, such as the internal heterogeneities, soft, dynamic substrate, and low gradient of peat drainage. This has previously made it difficult to collect spatial data required for restoration projects that seek to support spring obligate and thermally stressed species such as trout. Tidmarsh Farms is a 577-acre site in Southeastern Massachusetts where 100+ years of cranberry farming has significantly altered the original peatland hydrodynamics and ecology. Farming practices such as the regular application of sand, straightening of the main channel, and addition of drainage ditches has strongly degraded this peatland ecosystem. Our research has overlain non-invasive geophysical, thermal, and water isotopic data from the Tidmarsh Farms peatland to provide a detailed visualization of how subsurface peat structure and spring patterns correlate. Ground penetrating radar (GPR) has proven particularly useful in characterizing internal peat structure and the mineral soil interface beneath peatlands, we interpolate the peatland basin at a large scale (1 km2) and compare this 3-D surface to the locations of springs on the peat platform. Springs, expressed as cold anomalies in summer and warm anomalies in winter, were specifically located by combining fiber-optic and infrared thermal surveys, utilizing the numerous relic agricultural drainage ditches as a sampling advantage. Isotopic signatures of the spring locations are used to distinguish local and regional discharge, differences that can be explained in part by the peat basin structure

  15. An unexpected role for mixotrophs in the response of peatland carbon cycling to climate warming

    NASA Astrophysics Data System (ADS)

    Jassey, Vincent E. J.; Signarbieux, Constant; Hättenschwiler, Stephan; Bragazza, Luca; Buttler, Alexandre; Delarue, Frédéric; Fournier, Bertrand; Gilbert, Daniel; Laggoun-Défarge, Fatima; Lara, Enrique; T. E. Mills, Robert; Mitchell, Edward A. D.; Payne, Richard J.; Robroek, Bjorn J. M.

    2015-11-01

    Mixotrophic protists are increasingly recognized for their significant contribution to carbon (C) cycling. As phototrophs they contribute to photosynthetic C fixation, whilst as predators of decomposers, they indirectly influence organic matter decomposition. Despite these direct and indirect effects on the C cycle, little is known about the responses of peatland mixotrophs to climate change and the potential consequences for the peatland C cycle. With a combination of field and microcosm experiments, we show that mixotrophs in the Sphagnum bryosphere play an important role in modulating peatland C cycle responses to experimental warming. We found that five years of consecutive summer warming with peaks of +2 to +8°C led to a 50% reduction in the biomass of the dominant mixotrophs, the mixotrophic testate amoebae (MTA). The biomass of other microbial groups (including decomposers) did not change, suggesting MTA to be particularly sensitive to temperature. In a microcosm experiment under controlled conditions, we then manipulated the abundance of MTA, and showed that the reported 50% reduction of MTA biomass in the field was linked to a significant reduction of net C uptake (-13%) of the entire Sphagnum bryosphere. Our findings suggest that reduced abundance of MTA with climate warming could lead to reduced peatland C fixation.

  16. An unexpected role for mixotrophs in the response of peatland carbon cycling to climate warming.

    PubMed

    Jassey, Vincent E J; Signarbieux, Constant; Hättenschwiler, Stephan; Bragazza, Luca; Buttler, Alexandre; Delarue, Frédéric; Fournier, Bertrand; Gilbert, Daniel; Laggoun-Défarge, Fatima; Lara, Enrique; Mills, Robert T E; Mitchell, Edward A D; Payne, Richard J; Robroek, Bjorn J M

    2015-01-01

    Mixotrophic protists are increasingly recognized for their significant contribution to carbon (C) cycling. As phototrophs they contribute to photosynthetic C fixation, whilst as predators of decomposers, they indirectly influence organic matter decomposition. Despite these direct and indirect effects on the C cycle, little is known about the responses of peatland mixotrophs to climate change and the potential consequences for the peatland C cycle. With a combination of field and microcosm experiments, we show that mixotrophs in the Sphagnum bryosphere play an important role in modulating peatland C cycle responses to experimental warming. We found that five years of consecutive summer warming with peaks of +2 to +8°C led to a 50% reduction in the biomass of the dominant mixotrophs, the mixotrophic testate amoebae (MTA). The biomass of other microbial groups (including decomposers) did not change, suggesting MTA to be particularly sensitive to temperature. In a microcosm experiment under controlled conditions, we then manipulated the abundance of MTA, and showed that the reported 50% reduction of MTA biomass in the field was linked to a significant reduction of net C uptake (-13%) of the entire Sphagnum bryosphere. Our findings suggest that reduced abundance of MTA with climate warming could lead to reduced peatland C fixation. PMID:26603894

  17. An unexpected role for mixotrophs in the response of peatland carbon cycling to climate warming

    PubMed Central

    Jassey, Vincent E. J.; Signarbieux, Constant; Hättenschwiler, Stephan; Bragazza, Luca; Buttler, Alexandre; Delarue, Frédéric; Fournier, Bertrand; Gilbert, Daniel; Laggoun-Défarge, Fatima; Lara, Enrique; T. E. Mills, Robert; Mitchell, Edward A. D.; Payne, Richard J.; Robroek, Bjorn J. M.

    2015-01-01

    Mixotrophic protists are increasingly recognized for their significant contribution to carbon (C) cycling. As phototrophs they contribute to photosynthetic C fixation, whilst as predators of decomposers, they indirectly influence organic matter decomposition. Despite these direct and indirect effects on the C cycle, little is known about the responses of peatland mixotrophs to climate change and the potential consequences for the peatland C cycle. With a combination of field and microcosm experiments, we show that mixotrophs in the Sphagnum bryosphere play an important role in modulating peatland C cycle responses to experimental warming. We found that five years of consecutive summer warming with peaks of +2 to +8°C led to a 50% reduction in the biomass of the dominant mixotrophs, the mixotrophic testate amoebae (MTA). The biomass of other microbial groups (including decomposers) did not change, suggesting MTA to be particularly sensitive to temperature. In a microcosm experiment under controlled conditions, we then manipulated the abundance of MTA, and showed that the reported 50% reduction of MTA biomass in the field was linked to a significant reduction of net C uptake (-13%) of the entire Sphagnum bryosphere. Our findings suggest that reduced abundance of MTA with climate warming could lead to reduced peatland C fixation. PMID:26603894

  18. EFFECTIVENESS AND REGULATORY ISSUES IN OIL SPILL BIOREMEDIATION: EXPERIENCES WITH THE EXXON VALDEZ OIL SPILL IN ALASKA

    EPA Science Inventory

    The use of bioremediation as a supplemental cleanup technology in the Exxon Valdez oil spill, in Prince William Sound, Alaska, has proven to be a good example of the problems and successes associated with the practical application of this technology. ield studies conducted by sci...

  19. Bringing Up an Online System: Experiences at the University of Alaska. Project Management: A Key to Successful Organization and Implementation.

    ERIC Educational Resources Information Center

    Gaylord, Thomas A.

    The adoption of an information systems implementation strategy that emphasized user involvement at the University of Alaska, the only public university in the state, is discussed. The university sought to provide an online Student Information System (SIS) that provided convenient procedures for registering, tracking, and grading students, as well…

  20. Modelling Holocene peatland and permafrost dynamics with the LPJ-GUESS dynamic vegetation model

    NASA Astrophysics Data System (ADS)

    Chaudhary, Nitin; Miller, Paul A.; Smith, Benjamin

    2016-04-01

    Dynamic global vegetation models (DGVMs) are an important platform to study past, present and future vegetation patterns together with associated biogeochemical cycles and climate feedbacks (e.g. Sitch et al. 2008, Smith et al. 2001). However, very few attempts have been made to simulate peatlands using DGVMs (Kleinen et al. 2012, Tang et al. 2015, Wania et al. 2009a). In the present study, we have improved the peatland dynamics in the state-of-the-art dynamic vegetation model (LPJ-GUESS) in order to understand the long-term evolution of northern peatland ecosystems and to assess the effect of changing climate on peatland carbon balance. We combined a dynamic multi-layer approach (Frolking et al. 2010, Hilbert et al. 2000) with soil freezing-thawing functionality (Ekici et al. 2015, Wania et al. 2009a) in LPJ-GUESS. The new model is named LPJ-GUESS Peatland (LPJ-GUESS-P) (Chaudhary et al. in prep). The model was calibrated and tested at the sub-arctic mire in Stordalen, Sweden, and the model was able to capture the reported long-term vegetation dynamics and peat accumulation patterns in the mire (Kokfelt et al. 2010). For evaluation, the model was run at 13 grid points across a north to south transect in Europe. The modelled peat accumulation values were found to be consistent with the published data for each grid point (Loisel et al. 2014). Finally, a series of additional experiments were carried out to investigate the vulnerability of high-latitude peatlands to climate change. We find that the Stordalen mire will sequester more carbon in the future due to milder and wetter climate conditions, longer growing seasons, and the carbon fertilization effect. References: - Chaudhary et al. (in prep.). Modelling Holocene peatland and permafrost dynamics with the LPJ-GUESS dynamic vegetation model - Ekici A, et al. 2015. Site-level model intercomparison of high latitude and high altitude soil thermal dynamics in tundra and barren landscapes. The Cryosphere 9: 1343

  1. Relationship between peatland hydrology and biogeochemistry

    NASA Astrophysics Data System (ADS)

    Roulet, N. T.

    2012-04-01

    The 'boreal forest' landscape is composed of upland forests, peatlands, some of which are treed, lakes, streams, and in North America, beaver ponds. Each of these landscapes present quite different biogeochemical environments due to differences in both abiotic and biotic processes and conditions. A significant amount of the carbon (C) in the boreal landscape is stored in peatlands, in part, due to the effect of the water storage on C cycling. The near saturated conditions affect the plants that can grow in peatlands and over the shorter term moisture variability controls the rate of C input to the peat. In the peat water limits the supply of electron donors and this has a profound effect on the C biogeochemistry. Near peat surface the moisture storage can be quite dynamic and mostly oxic conditions prevail, but redox conditions change significantly within a few tenth of a meter below the surface where water residence times increase orders of magnitude. This limits the supply of electron donors and other substrates that control the rate of C mineralization. Understanding the links among the moisture dynamics, the chemical thermodynamics of temporally variable saturated environments, and the quality of C is critical to determining the sensitivity of the C stored in peatlands to environmental change.

  2. Nitrogen dynamics in northern peatland ecosystems

    EPA Science Inventory

    Nitrogen pollution has become a global issue over the last century due to increased fertilizer use and burning of fossil fuels. Excess N has been responsible for algal blooms, hypoxic zones, climate change, and human health issues. Extent of peatlands in the Great Lakes basin is ...

  3. SPRUCE: Spruce and Peatland Responses under Climatic and Environmental Change

    DOE Data Explorer

    SPRUCE is an experiment to assess the response of northern peatland ecosystems to increases in temperature and exposures to elevated atmospheric CO2 concentrations. It is the primary component of the Terrestrial Ecosystem Science Scientific Focus Area of ORNL's Climate Change Program, focused on terrestrial ecosystems and the mechanisms that underlie their responses to climatic change. The experimental work is to be conducted in a Picea mariana [black spruce] - Sphagnum spp. bog forest in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). The site is located at the southern margin of the boreal peatland forest. It is an ecosystem considered especially vulnerable to climate change, and anticipated to be near its tipping point with respect to climate change. Responses to warming and interactions with increased atmospheric CO2 concentration are anticipated to have important feedbacks on the atmosphere and climate, because of the high carbon stocks harbored by such ecosystems.[copied from http://mnspruce.ornl.gov/] While some data files are restricted to access by project members only, others are available for public download now, even as research is being actively conducted.

  4. Holocene peatland initiation in the Greater Everglades

    NASA Astrophysics Data System (ADS)

    Dekker, Stefan; de Boer, Hugo; Dermody, Brian; Wagner-Cremer, Friederike; Wassen, Martin; Eppinga, Maarten

    2015-04-01

    The mechanisms involved in the initiation and development of the Greater Everglades peatland ecosystems in South Florida (USA) remain a topic of discussion. In this study, we present an overview of basal ages of peat deposits in South Florida, which shows two major episodes of peatland initiation between 7.0-4.5 kyr and 3.5-2.0 kyr. Our analysis of regional climate proxy datasets led to three alternative hypotheses that may explain the timing and duration of these two peatland initiation episodes: (1) decreased drainage due to relative sea level (RSL) rise during the Holocene (2) gradual increase in precipitation throughout the Holocene, and (3) a combination of increasing precipitation, rising RSL and oscillations in the climate system. We test whether these three hypotheses can explain the pattern of initiation and development of the Greater Everglades peatlands using models that simulate the non-linear processes involved in peat production and decomposition in combination with the local drainage conditions of Southern Florida. The model results suggest that RSL-rise alone cannot predict the onset of peat initiation in the Greater Everglades using our model setup. The model also implies that the climate was wet enough for peat development also during the early Holocene. The first two hypothesized mechanisms in combination with climate oscillations may explain the onset of peat accumulation at 8.2 kyr BP. The two-phased character of peat land initiation may be explained by the spatial distribution of local drainage conditions. As peatland development is highly non-linear, our model uncovers a mechanistic way how peats can suddenly shift from a dry high equilibrium to a wet low equilibrium resulting in lake formation as observed in paleo-ecological studies in the Greater Everglades.

  5. Seismic images of the Brooks Range fold and thrust belt, Arctic Alaska, from an integrated seismic reflection/refraction experiment

    USGS Publications Warehouse

    Levander, A.; Fuis, G.S.; Wissinger, E.S.; Lutter, W.J.; Oldow, J.S.; Moore, T.E.

    1994-01-01

    We describe results of an integrated seismic reflection/refraction experiment across the Brooks Range and flanking geologic provinces in Arctic Alaska. The seismic acquisition was unusual in that reflection and refraction data were collected simultaneously with a 700 channel seismograph system deployed numerous times along a 315 km profile. Shot records show continuous Moho reflections from 0-180 km offset, as well as numerous upper- and mid-crustal wide-angle events. Single and low-fold near-vertical incidence common midpoint (CMP) reflection images show complex upper- and middle-crustal structure across the range from the unmetamorphosed Endicott Mountains allochthon (EMA) in the north, to the metamorphic belts in the south. Lower-crustal and Moho reflections are visible across the entire reflection profile. Travel-time inversion of PmP arrivals shows that the Moho, at 33 km depth beneath the North Slope foothills, deepens abruptly beneath the EMA to a maximum of 46 km, and then shallows southward to 35 km at the southern edge of the range. Two zones of upper- and middle-crustal reflections underlie the northern Brooks Range above ~ 12-15 km depth. The upper zone, interpreted as the base of the EMA, lies at a maximum depth of 6 km and extends over 50 km from the range front to the north central Brooks Range where the base of the EMA outcrops above the metasedimentary rocks exposed in the Doonerak window. We interpret the base of the lower zone, at ~ 12 km depth, to be from carbonate rocks above the master detachment upon which the Brooks Range formed. The seismic data suggest that the master detachment is connected to the faults in the EMA by several ramps. In the highly metamorphosed terranes south of the Doonerak window, the CMP section shows numerous south-dipping events which we interpret as a crustal scale duplex involving the Doonerak window rocks. The basal detachment reflections can be traced approximately 100 km, and dip southward from about 10-12 km

  6. Relationship between Trophic Status and Methanogenic Pathways in Alaskan Peatlands

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Liu, X.; Sidelinger, W.; Wang, Y.; Hines, M. E.; Langford, L.; Chanton, J.

    2015-12-01

    To improve predictions of naturally emitted CH4 from northern wetlands, it is necessary to further examine the methanogenic pathways in these wetlands. Stable isotope C ratios (δ13C) have been used as a robust tool to distinguish different pathways, but different sources of parent compounds (acetate and CO2) with unique δ13C may add complexity to previously established criteria. Large portions of peatlands accommodate a mixture of different sphagna and sedges. Plant species may look very similar and belong to the same genus but are different morphologically and physiologically. To better understand the relationships between surface vegetation patterns and methanogenic pathways, 26 peatland sites were studied in Fairbanks and Anchorage, Alaska in summers of 2014 and 2015. These sites were ordinated using multiple factor analysis into 3 clusters based on pH, temp, CH4 and volatile fatty acids production rates, δ13C values, and surface vegetation species/pattern. In the low-pH trophic cluster (pH~3.5), non-vascular/vascular plant ratios (NV/V) were ~ 0.87 and dominated by diverse Sphagnum species and specific sedges (Eriophorum vaginatum), and fermentation was the dominant end-point in decomposition with no CH4 detected. Although NV/V is about the same in the intermediate cluster (0.74) (pH~4.5), and Sphagnum squarrosum was largely present, both hydrogenotrophic (HM) and acetoclastic methanogenesis (AM) were very active. Syntrophy was present at certain sites, which may provide CO2 with unique δ13C for CH4 production. At the highest pH trophic cluster examined in this study (pH~5), non-vascular plants were almost not existent and Carex aquatilis dominated. CH4 production rates (mainly HM) were slower than those in the intermediate cluster and the apparent fractionation factor a was lower than in the sites with syntrophy, which warrants further investigation of the position and compound specific δ13C analysis of volatile fatty acids.

  7. Interactive effects of fire, soil climate, and moss on CO2 fluxes in black spruce ecosystems of interior Alaska

    USGS Publications Warehouse

    O'Donnell, J. A.; Turetsky, M.R.; Harden, J.W.; Manies, K.L.; Pruett, L.E.; Shetler, G.; Neff, J.C.

    2009-01-01

    Fire is an important control on the carbon (C) balance of the boreal forest region. Here, we present findings from two complementary studies that examine how fire modifies soil organic matter properties, and how these modifications influence rates of decomposition and C exchange in black spruce (Picea mariana) ecosystems of interior Alaska. First, we used laboratory incubations to explore soil temperature, moisture, and vegetation effects on CO2 and DOC production rates in burned and unburned soils from three study regions in interior Alaska. Second, at one of the study regions used in the incubation experiments, we conducted intensive field measurements of net ecosystem exchange (NEE) and ecosystem respiration (ER) across an unreplicated factorial design of burning (2 year post-fire versus unburned sites) and drainage class (upland forest versus peatland sites). Our laboratory study showed that burning reduced the sensitivity of decomposition to increased temperature, most likely by inducing moisture or substrate quality limitations on decomposition rates. Burning also reduced the decomposability of Sphagnum-derived organic matter, increased the hydrophobicity of feather moss-derived organic matter, and increased the ratio of dissolved organic carbon (DOC) to total dissolved nitrogen (TDN) in both the upland and peatland sites. At the ecosystem scale, our field measurements indicate that the surface organic soil was generally wetter in burned than in unburned sites, whereas soil temperature was not different between the burned and unburned sites. Analysis of variance results showed that ER varied with soil drainage class but not by burn status, averaging 0.9 ?? 0.1 and 1.4 ?? 0.1 g C m-2d-1 in the upland and peatland sites, respectively. However, a more complex general linear model showed that ER was controlled by an interaction between soil temperature, moisture, and burn status, and in general was less variable over time in the burned than in the unburned sites

  8. 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

  9. Effects of rotifers, copepods and chironomid larvae on microbial communities in peatlands.

    PubMed

    Mieczan, Tomasz; Niedźwiecki, Michał; Tarkowska-Kukuryk, Monika

    2015-10-01

    Interactions between the microbial loop and the classical grazing food chain are essential to ecosystem ecology. The goal of the present study was to examine the impact of chironomid larvae, rotifers and copepods on the major components of the microbial food web (algae, bacteria, heterotrophic flagellates, testate amoebae and ciliates) in peatlands. Two enclosure experiments were carried out in a Sphagnum peatland. In the experiments we manipulated rotifers, copepods and macroinvertebrates, i.e. chironomid larvae (Psectrocladius sordidellus gr). During the experiments variation was observed in the abundance of potential predators. The beginning of the first experiment was distinguished by dominance of rotifers, but five days later copepods were dominant. In the second experiment copepods dominated. The results of this study are the first to suggest a substantial impact of chironomid larvae, rotifers and copepods on microorganism communities in peatland ecosystems. The impact is reflected by both a decrease in the abundance and biomass of testate amoebae and ciliates and a transformation of the size structure of bacteria. Heterotrophic flagellates (HNF) were not controlled by metazoans, but rather by testate amoebae and ciliates, as HNF were more abundant in the control treatment. PMID:26322497

  10. Seasonal Oxygen Dynamics in a Thermokarst Bog in Interior Alaska: Implications for Rates of Methane Oxidation

    NASA Astrophysics Data System (ADS)

    Neumann, R. B.; Moorberg, C.; Wong, A.; Waldrop, M. P.; Turetsky, M. R.

    2015-12-01

    Methane is a potent greenhouse gas, and wetlands represent the largest natural source of methane to the atmosphere. However, much of the methane generated in anoxic wetlands never gets emitted to the atmosphere; up to >90% of generated methane can get oxidized to carbon dioxide. Thus, oxidation is an important methane sink and changes in the rate of methane oxidation can affect wetland methane emissions. Most methane is aerobically oxidized at oxic-anoxic interfaces where rates of oxidation strongly depend on methane and oxygen concentrations. In wetlands, oxygen is often the limiting substrate. To improve understanding of belowground oxygen dynamics and its impact on methane oxidation, we deployed two planar optical oxygen sensors in a thermokarst bog in interior Alaska. Previous work at this site indicated that, similar to other sites, rates of methane oxidation decrease over the growing season. We used the sensors to track spatial and temporal patterns of oxygen concentrations over the growing season. We coupled these in-situ oxygen measurements with periodic oxygen injection experiments performed against the sensor to quantify belowground rates of oxygen consumption. We found that over the season, the thickness of the oxygenated water layer at the peatland surface decreased. Previous research has indicated that in sphagnum-dominated peatlands, like the one studied here, rates of methane oxidation are highest at or slightly below the water table. It is in these saturated but oxygenated locations that both methane and oxygen are available. Thus, a seasonal reduction in the thickness of the oxygenated water layer could restrict methane oxidation. The decrease in thickness of the oxygenated layer coincided with an increase in the rate of oxygen consumption during our oxygen injection experiments. The increase in oxygen consumption was not explained by temperature; we infer it was due to an increase in substrate availability for oxygen consuming reactions and

  11. Using Bryophytes and Stable isotopes to Assess Paleohydrological Changes in a Subarctic Alaskan Peatland

    NASA Astrophysics Data System (ADS)

    Jones, M.; Peteet, D.; Sambrotto, R.

    2007-12-01

    Hydrologic changes resulting from climate change have important effects on vegetation change and global feedback cycles in the high latitudes. In an attempt to move beyond pollen analysis to interpret past climate, a number of geochemical and biological proxies were used, including bulk peat δ 13C, δ15N, and bryophytes, to make paleohydrological inferences from peat cores in south central Alaska. Bryophyte species distribution and composition are sensitive to water table position and pH, making them good candidates for paleohydrologic analyses. Bryophyte species were identified in \\1-m2 plots from the forest edge to the wettest swale across numerous peatland sites on the Kenai Peninsula, taking pH, conductivity, and temperature measurements for each plot. This modern calibration was used to conduct bryophyte analysis from two peatland cores from the Kenai Peninsula lowlands dated to 14.2 ka and 18.8 ka. Both records exhibit good preservation of both leaves and stems, allowing for analysis and identification. Late-glacial domination of brown moss species denotes rich fen conditions, and high moisture availability, as is indicated in the δ13C record. Increased δ13C values ca. 10 ka indicate a shift from moister to drier conditions, and the bryophyte species switch to higher hummock brown moss species and Sphagnum spp. Similar shifts in δ15N from negative values to near 0‰ suggest a switch of nutrient input to the fen from combined nitrogen pools to atmospheric nitrogen sources. The bryophyte species composition shows a dominance of acidic poor fen conditions in the mid- to late- Holocene. These shifts corroborate what was previously interpreted in the pollen and macrofossil record from these peatland sites.

  12. Seismology Outreach in Alaska

    NASA Astrophysics Data System (ADS)

    Gardine, L.; Tape, C.; West, M. E.

    2014-12-01

    Despite residing in a state with 75% of North American earthquakes and three of the top 15 ever recorded, most Alaskans have limited knowledge about the science of earthquakes. To many, earthquakes are just part of everyday life, and to others, they are barely noticed until a large event happens, and often ignored even then. Alaskans are rugged, resilient people with both strong independence and tight community bonds. Rural villages in Alaska, most of which are inaccessible by road, are underrepresented in outreach efforts. Their remote locations and difficulty of access make outreach fiscally challenging. Teacher retention and small student bodies limit exposure to science and hinder student success in college. The arrival of EarthScope's Transportable Array, the 50th anniversary of the Great Alaska Earthquake, targeted projects with large outreach components, and increased community interest in earthquake knowledge have provided opportunities to spread information across Alaska. We have found that performing hands-on demonstrations, identifying seismological relevance toward career opportunities in Alaska (such as natural resource exploration), and engaging residents through place-based experience have increased the public's interest and awareness of our active home.

  13. Greenhouse gas flux from tropical peatlands: context and controls

    NASA Astrophysics Data System (ADS)

    Page, Susan; Jauhiainen, Jyrki; Hooijer, Aljosja

    2010-05-01

    Peatlands play a key role within the global carbon cycle by storing a disproportionately large amount of soil carbon relative to other terrestrial ecosystems. Peatland systems have accumulated carbon through an imbalance between the uptake and release of CO2 from and to the atmosphere. In a pristine condition, tropical peat swamp forest is one of the world's most efficient carbon sequestering ecosystems as a result of substantial biomass production and the waterlogged condition of the peat, which reduces significantly the rate of organic matter decomposition. Tropical peat deposits have acted as sinks of atmospheric carbon since at least the beginning of the Holocene and, in some cases, the Late Pleistocene. They currently store ~ 65 Gt C, most of which is located in thick deposits in Southeast Asia. Tropical peatlands are, however, vulnerable to destabilisation through both human and climate induced changes. The former include poor forest and land management practices, drainage, large-scale conversion to plantation agriculture, and fire; these lead to degradation and reduction of the peatland carbon store and contribute to greenhouse gas emissions, whilst compromising other valuable ecosystem services. Climate induced changes include susceptibility to drought-impacts, particularly during ENSO-events; there are also initial indications that regional climates in areas with extensive peatlands are experiencing reduced rainfall, which threatens longer term peatland sustainability. This paper reviews the current understanding of carbon-climate-human interactions on tropical peatlands. It focuses on the main causes of peatland degradation, in particular natural and anthropogenic changes in peatland hydrology; considers the risks that hydrological change, especially water-table drawdown, poses to the peatland carbon pool; and assesses the scale of peatland drainage-associated CO2 emissions, which are currently of the order of ~250 Mt C yr-1 for Southeast Asian peatlands

  14. Modeling water table dynamics in managed and restored peatlands

    NASA Astrophysics Data System (ADS)

    Cresto Aleina, Fabio; Rasche, Livia; Hermans, Renée; Subke, Jens-Arne; Schneider, Uwe; Brovkin, Victor

    2016-04-01

    European peatlands have been extensively managed over past centuries. Typical management activities consisted of drainage and afforestation, which lead to considerable damage to the peat and potentially significant carbon loss. Recent efforts to restore previously managed peatlands have been carried out throughout Europe. These restoration efforts have direct implications for water table depth and greenhouse gas emissions, thus impacting on the ecosystem services provided by peatland areas. In order to quantify the impact of peatland restoration on water table depth and greenhouse gas budget, We coupled the Environmental Policy Integrated Climate (EPIC) model to a process-based model for methane emissions (Walter and Heimann, 2000). The new model (EPIC-M) can potentially be applied at the European and even at the global scale, but it is yet to be tested and evaluated. We present results of this new tool from different peatlands in the Flow Country, Scotland. Large parts of the peatlands of the region have been drained and afforested during the 1980s, but since the late 1990s, programs to restore peatlands in the Flow Country have been enforced. This region offers therefore a range of peatlands, from near pristine, to afforested and drained, with different resoration ages in between, where we can apply the EPIC-M model and validate it against experimental data from all land stages of restoration Goals of this study are to evaluate the EPIC-M model and its performances against in situ measurements of methane emissions and water table changes in drained peatlands and in restored ones. Secondly, our purpose is to study the environmental impact of peatland restoration, including methane emissions, due to the rewetting of drained surfaces. To do so, we forced the EPIC-M model with local meteorological and soil data, and simulated soil temperatures, water table dynamics, and greenhouse gas emissions. This is the first step towards a European-wide application of the EPIC

  15. Modelling methane fluxes from managed and restored peatlands

    NASA Astrophysics Data System (ADS)

    Cresto Aleina, F.; Rasche, L.; Hermans, R.; Subke, J. A.; Schneider, U. A.; Brovkin, V.

    2015-12-01

    European peatlands have been extensively managed over past centuries. Typical management activities consisted of drainage and afforestation, which lead to considerable damage to the peat and potentially significant carbon loss. Recent efforts to restore previously managed peatlands have been carried out throughout Europe. These restoration efforts have direct implications for water table depth and greenhouse gas emissions, thus impacting on the ecosystem services provided by peatland areas. In order to quantify the impact of peatland restoration on water table depth and greenhouse gas budget, We coupled the Environmental Policy Integrated Climate (EPIC) model to a process-based model for methane emissions (Walter and Heimann, 2000). The new model (EPIC-M) can potentially be applied at the European and even at the global scale, but it is yet to be tested and evaluated. We present results of this new tool from different peatlands in the Flow Country, Scotland. Large parts of the peatlands of the region have been drained and afforested during the 1980s, but since the late 1990s, programs to restore peatlands in the Flow Country have been enforced. This region offers therefore a range of peatlands, from near pristine, to afforested and drained, with different resoration ages in between, where we can apply the EPIC-M model and validate it against experimental data from all land stages of restoration. Goals of this study are to evaluate the EPIC-M model and its performances against in situ measurements of methane emissions and water table changes in drained peatlands and in restored ones. Secondly, our purpose is to study the environmental impact of peatland restoration, including methane emissions, due to the rewetting of drained surfaces. To do so, we forced the EPIC-M model with local meteorological and soil data, and simulated soil temperatures, water table dynamics, and greenhouse gas emissions. This is the first step towards a European-wide application of the EPIC

  16. Upscaling methane emission hotspots in boreal peatlands

    NASA Astrophysics Data System (ADS)

    Cresto Aleina, Fabio; Runkle, Benjamin R. K.; Bruecher, Tim; Kleinen, Thomas; Brovkin, Victor

    2016-04-01

    Small-scale surface heterogeneities can influence land-atmosphere fluxes and therefore carbon, water and energy budgets on a larger scale. This effect is of particular relevance for high-latitude ecosystems, because of the great amount of carbon stored in their soils. Upscaling such small-scale surface heterogeneities and their effects to larger scales is a challenging issue in land surface modeling. We developed a novel approach to upscale local methane emissions in a boreal peatland from the micro-topographic scale to the landscape-scale. We based this parameterization on the analysis of the water table pattern generated by the Hummock-Hollow model (Cresto Aleina et al., 2015), a micro-topography resolving model for peatland hydrology and methane emissions. By computing the water table at the micro-topographic scale, the Hummock-Hollow model is able to describe the effects of micro-topography on hydrology and methane emissions in a typical boreal peatland. We introduce the new parameterization of methane hotspots in a global model-like version of the Hummock-Hollow model. This latter version underestimates methane emissions because of the lack of representation of micro-topographic controls on peatland hydrology. We tested the robustness of the parameterization by simulating methane emissions for the present day and for the next century, forcing the model with three different RCP scenarios. The Hotspot parameterization, despite being calibrated for the 1976-2005 climatology, mimics the output of the micro-topography resolving model for all the simulated scenarios. The new approach bridges the scale gap of methane emissions between this version of the model and the configuration explicitly resolving micro-topography.

  17. Dynamics of the recovery of damaged tundra vegetation: preliminary results of revegetation experiments of maritime tundra with Elymus mollis on Adak Island, Alaska. Progress report

    SciTech Connect

    Amundsen, C C; McCord, R A

    1982-08-01

    The vegetation of the central Aleutian Islands, Alaska is maritime tundra (Amundsen, 1977). While maritime tundra is not characterized by the presence of permafrost, the soil temperatures remain low (5 to 7/sup 0/C) year-round (Williams, 1980). The low soil temperature, a high level of soil moisture, and a low level of incident solar radiation are thought to delay the development of the vegetation. Natural revegetation of natural or man made open areas is relatively slow. Disturbed areas from World War II military activity are not completely revegetated after almost 40 years. Because of the windy and wet climate of the region, exposed soil is unstable and subject to extensive freeze-thaw action and erosion. Insults to the vegetation, both marine and aeolian, are common. Successful reproduction by seed is uncommon among species of this flora. The primary means of reproduction appears to be by vegetative propagules which are usually fragments of the shoot and rhizome. While the transport of the fragments by wind and water aids in the dispersal of the propagules, the same action often removes these fragments from open areas. This later activity further delays the revegetation of open and disturbed areas. Elymus mollis Trin. is the most successful major native species found to date as it fragments due to wind and water action and transplants easily. Transplanting experiments with sprigs of Elymus mollis Trin. have been conducted on Adak Island, Alaska since 1977. Preliminary results indicate that Elymus mollis may be transplanted for revegetation with a survival rate of at least 90 percent. Experiments were set up in 1979 to determine appropriate planting density, sprig rhizome length, and best time of year for transplanting. Preliminary results for these experiments are reported here.

  18. Constraining peatland environmental change: exploiting the emerging eastern North American crypto-tephrostratigraphic record

    NASA Astrophysics Data System (ADS)

    Mackay, H.; Hughes, P. D.; Langdon, P.

    2013-12-01

    The relatively recent advances in tephrochronology have led to the investigation of non-visible (crypto) tephra horizons in sediment distal from volcanic origins. Such studies have been predominantly centered on western Europe; however the potential of North American cryptotephras is rapidly emerging. This not only facilitates the construction of more robust chronologies in areas thought to be outside the scope of this technique, but also the provision of isochrons enhances comparisons of environmental spatial synchronicity across sites and regions. Four tephrostratigraphies across a transect of peatlands in Maine, Nova Scotia and south-western Newfoundland have been constructed. A total of 18 horizons were detected over the last ca. 4000 years, the preliminary geochemical analysis of which suggest that all constrained eruptions originate from the Cascade Range and Alaska ca. 5000-6000 km to the west of the sites. These results complement the one existing record from eastern Newfoundland (Pyne-O'Donnell et al. 2012), facilitating the extension of the late Holocene crypto-tephrostratigraphic framework for the eastern seaboard of North America. Peatlands are considered to be ideal archives for preserving tephrostratigraphies since cryptotephra horizons are often present in discrete layers, thought to represent primary airfall. Such preservation in this setting is critiqued here, assisted by radiocarbon measurements. The tephra horizons are used as pinning-points between records to address the wider aim of the study: to examine the terrestrial manifestations of late Holocene climatic change across an eastern North American climatic gradient. Of particular interest are the temporal and spatial characteristics of changes in peatland accumulation and reconstructed water table depth during the most dominant late Holocene climatic perturbations: the Medieval Climatic Anomaly and the Little Ice Age. This time period is constrained by the most dominant eruption, White River

  19. Viewpoints: Reflections on the Principalship in Alaska.

    ERIC Educational Resources Information Center

    Hagstrom, David A., Ed.

    In this collection, 32 Alaskan principals, retired principals, assistant principals, and principals-to-be share their experiences as administrators and reflect on their feelings about the nature of the work and about schooling issues in Alaska. Nine of the writings were selected from "Totem Tales," the newsletter of Alaska's Association of…

  20. Variability of Carbon Exchanges Between Two Contrasting Northern Peatlands

    NASA Astrophysics Data System (ADS)

    Roulet, N. T.; Nilsson, M.

    2008-12-01

    Northern peatland contain about one quarter of the world's terrestrial carbon. It appears that many peatlands still remains a small, but persistent sinks of carbon dioxide and sources of methane. The sink strength is small compared to actively growing boreal forests but equal to the Holocene average peatland carbon accumulation. This suggests that the function of northern peatlands, with regard to C sequestration, has not change relative to the Holocene average uptake. In contrast to forested ecosystems there have been few long-term continuous measurements of the components of the C balance of peatlands ecosystems. In addition to measurements of net ecosystem exchange and net methane emission (or uptake), the C balance of peatlands requires accurate estimates of the loss of carbon dissolved in runoff. Multi-year measurements of these three major exchanges have been made in contrasting northern peatlands: Mer Bleue, a raised ombrotrophic bog located at the boreal - temperate boundary in eastern Canada, and Degero Stormyr, a mineral poor, oligotrophic fen located in northern Sweden. Despite very different plant communities and moisture regimes the long-term average NEE, methane exchange and net loss of carbon dissolved in water are surprisingly similar in these two systems. However, Mer Bleue has a much greater inter-annual variability in the exchanges than does Degero Stormyr peatland. The difference in exchanges appears related to differences in the variability in moisture supply to the vegetation layer and water storage in the peat. In the early 1990s, the eminent peatland ecologist, Eville Gorham estimated, with few observations, the relative importance of the C balance components of northern peatlands. The multi-year records indicate that these early estimates with reasonable good within an order of magnitude.

  1. Peatland carbon cycling at a Scottish wind farm: the role of plant-soil interactions

    NASA Astrophysics Data System (ADS)

    Richardson, Harriett; Whitaker, Jeanette; Waldron, Susan; Ostle, Nick

    2013-04-01

    Peatlands play a fundamental role in the terrestrial carbon cycle by storing 1/3 of the world's soil carbon (Limpens et al. 2008). In the UK, peatlands are often located in areas with potential for electricity generation by harvesting wind energy. Concerns have been raised, however, over the stability of these carbon stocks when large scale wind developments are sited upon them. This project aims to improve understanding of the impact of wind farms on carbon sequestration in peatlands. Wind turbine 'wake-effects' can alter microclimatic conditions, as a result of significant differences in air temperature, humidity, wind speed and turbulence (Baidya Roy and Traiteur 2010). These changes are likely to have a significant impact on above and below ground abiotic conditions and biotic properties, together with the processes they regulate that govern peatland carbon cycling. Specifically, the effects of interactions between typical peatland plant functional types (graminoids, bryophytes and shrubs) (Ward et al. 2009) and peat microbial community composition and function are poorly resolved. We examined a spatial gradient across an area of blanket bog at Black Law wind farm (Lanarkshire, Scotland) and executed a series of controlled mesocosm experiments to examine the impacts of potential microclimatic changes on plant-soil interactions and carbon sequestration processes. In particular we focused on the form and function of plant and microbial communities as determinants of decomposition (Ward et al. 2010) and greenhouse gas (GHG) emissions (Artz 2009). Measurements of plant-litter-soil carbon, nitrogen, microbial community composition (i.e. phospholipid fatty acid biomarkers) and litter mass loss have been made across the wind farm peatland to attribute spatial variance in biotic and biogeochemical properties. In addition, multi-factorial mesocosm experiments have been made to determine how abiotic and biotic changes caused by wind farm effects could influence peat GHG

  2. Breaking the cycle/mending the hoop: adverse childhood experiences among incarcerated American Indian/Alaska Native women in New Mexico.

    PubMed

    De Ravello, Lori; Abeita, Jessica; Brown, Pam

    2008-03-01

    Incarcerated American Indian/Alaska Native (AI/AN) women have multiple physical, social, and emotional concerns, many of which may stem from adverse childhood experiences (ACE). We interviewed 36 AI/AN women incarcerated in the New Mexico prison system to determine the relationship between ACE and adult outcomes. ACE assessment included physical neglect, dysfunctional family (e.g., household members who abused substances, were mentally ill or suicidal, or who were incarcerated), violence witnessed in the home, physical abuse, and sexual abuse. The most prevalent ACE was dysfunctional family (75%), followed by witnessing violence (72%), sexual abuse (53%), physical abuse (42%), and physical neglect (22%). ACE scores were positively associated with arrests for violent offenses, lifetime suicide attempt(s), and intimate partner violence. PMID:18350429

  3. 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

  4. Alaska Resource Data File, Noatak Quadrangle, Alaska

    USGS Publications Warehouse

    Grybeck, Donald J.; Dumoulin, Julie A.

    2006-01-01

    This report gives descriptions of the mineral occurrences in the Noatak 1:250,000-scale quadrangle, Alaska. The data presented here are maintained as part of a statewide database on mines, prospects and mineral occurrences throughout Alaska.

  5. A drift experiment to assess the influence of wind on recovery of oiled seabirds on St Paul Island, Alaska

    USGS Publications Warehouse

    Flint, P.L.; Fowler, A.C.

    1998-01-01

    We used wooden blocks to estimate the proportion of oiled seabird carcasses that were likely to be recovered on beaches of St Paul Island, Alaska following a near-shore oil spill. We released a total of 302 blocks 6 km north of the island in 1997 at the site of a 17 II 1996 oil spill. We used a paired design and released half the blocks when the winds were onshore and released the second half when the winds were offshore. We systematically searched beaches after the second release to recover blocks. We recovered 93 of 152 (61%) blocks released when winds were onshore but only 1 of 150 (0.7%) blocks released when winds were offshore. Given that winds following the 1996 spill were offshore, we conclude that most birds killed at sea following the 1996 spill were likely not recovered on beaches.

  6. Integrating peatlands and permafrost into a dynamic global vegetation model: 1. Evaluation and sensitivity of physical land surface processes

    NASA Astrophysics Data System (ADS)

    Wania, R.; Ross, I.; Prentice, I. C.

    2009-09-01

    Northern peatlands and permafrost soils are associated with large carbon stocks. Rising temperatures are likely to affect the carbon balance in high-latitude ecosystems, but to what degree is uncertain. We have enhanced the Lund-Potsdam-Jena (LPJ) dynamic global vegetation model by introducing processes necessary to simulate permafrost dynamics, peatland hydrology, and peatland vegetation. The new version, LPJ-WHy v1.2, was used to study soil temperature, active layer depth, permafrost distribution, and water table position. Modeled soil temperatures agreed well with observations, apart from a Siberian site where the soil is insulated by an extensive shrub layer. Water table positions were generally in the range of observations, with some exceptions. Simulated active layer depth showed a mean absolute error of 44 cm when compared to observations, but the error was reduced to 25 cm when the soil type for seven sites was manually corrected to mirror local conditions. A sensitivity test, in which temperature and precipitation were varied independently, showed that soil temperatures and active layer depths increased more under higher temperatures when precipitation was increased at the same time. The sensitivity experiment suggested persisting wet conditions in peatlands even under temperature increases of up to 9°C as long as annual precipitation is allowed to increase with temperature to the extent indicated by climate model experiments.

  7. Modeling methane emissions from boreal peatlands

    NASA Astrophysics Data System (ADS)

    Raivonen, Maarit; Smolander, Sampo; Mäkelä, Jarmo; Tomasic, Marin; Aalto, Tuula; Markkanen, Tiina; Susiluoto, Jouni; Kleinen, Thomas; Brovkin, Victor; Rinne, Janne; Lohila, Annalea; Aurela, Mika; Vesala, Timo

    2014-05-01

    Natural wetlands are a significant source of methane (CH4): they have been estimated to account for about 30% of total global CH4 emissions. At the moment, the emission estimates are highly uncertain. These natural emissions respond to climatic variability, so it is necessary to understand their dynamics, in order to be able to predict how they affect the greenhouse-gas balance in the future. We have developed a model of CH4 production and transport in boreal peatlands. The aim is to make it a part of JSBACH, the land component of the Earth System Model of MPI Hamburg. The soil carbon model of JSBACH simulates peatland carbon processes like peat accumulation and decomposition and our CH4 module simulates production of CH4 as a proportion of the anaerobic peat decomposition, transport of CH4 and oxygen between the soil and the atmosphere, and oxidation of CH4 by methanotrophic microbes. The model has the three main pathways for transport: diffusion in aerenchymatous plants and in peat pores (water and air filled) and CH4 ebullition. The oxidation of CH4 depends on the oxygen concentrations in the peat. The model is largely based on existing models of CH4 production and transport but it includes some modifications that we will present here. We also will present the results of the first validations against observational data. The datasets are from two Finnish peatland sites, Siikaneva (southern) and Lompolojänkkä (northern Finland). Measurements of eddy covariance CH4 and CO2 fluxes and meteorological variables, as well as diverse ecological studies have been carried out on both sites over several years.

  8. 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.

  9. Temperature sensitivity of frozen peatland soils organic matter decomposition (North-Western Siberia, Nadym site, Russia)

    NASA Astrophysics Data System (ADS)

    Tarkhov, Matvey; Matyshak, George; Yakushev, Andrey; Bobrik, Ann

    2016-04-01

    Peatland soils play a considerable role in carbon cycle because of storing approximately 50% of total Earth's soils carbon. The steady temperature increase in arctic soils may cause a rapid organic matter decomposition in thawed layers - that will result in additional significant greenhouse gases emission (CO2, CH4). For further predictions improvement of soils response to global climate changes it is necessary to estimate the temperature sensitivity of soils organic matter decomposition. The purpose of the study was to estimate the response of frozen peatland soils organic matter to increase in the temperature of their functioning. The study object was frozen peatland soils of forest-tundra (the Tyumen region), developing under permafrost conditions. Weakly and medium decomposed moss peat samples were taken from different depths for laboratory studies and stored at 4 °C before the experiment started. At laboratory the response of CO2 efflux, basal respiration (BR) and soils enzymatic (esters) activity (SEA) to temperature increase was estimated. For 1.5 months one part of peat samples was subjected to sequential temperature increase from 4 to 25 °C and CO2 efflux was measured. Another part of the peat samples was simultaneously incubated at 4, 15 and 25 °C for 1-4 days for BR and SEA estimation. To identify the specifics of frozen peatland soils response the identical experiments were done with peat samples from southern taiga (the Moscow region). First results showed the contrast response of peatland soils from different ecosystems to temperature increase. For all studied soils the positive feedback to temperature increase was noticed, however the organic matter mineralization rate, estimated by CO2 efflux, differed a lot. The CO2 efflux values of forest-tundra samples were 3 times lower in comparison with southern taiga on average: the maximal difference was at 16-22 °C range. The microbial biomass activity, estimated by BR and SEA, also tended to increase

  10. Mitigating wildfire carbon loss in managed northern peatlands through restoration

    NASA Astrophysics Data System (ADS)

    Granath, Gustaf; Lukenbach, Max; Moore, Paul; Waddington, James

    2015-04-01

    Wildfire frequency and severity are expected to increase in forested temperate and boreal ecosystems. Recent research indicates that northern peatlands are no exceptions to these risks and may be particularly vulnerable. These ecosystems represent a major component of the global carbon cycle and serve as contemporary and long-term net carbon sink. However, severe, deep burning, fires on these organic soils may not only compromise long-term carbon storage by releasing large amounts of carbon but also impose a real threat to human health and economies through smoke pollution and large costs in fire suppression, respectively. As research in tropical peatlands has revealed, these risks are likely enhanced when northern peatlands are drained and/or mined. Here we examine whether peatland restoration (re-wetting) practices can mitigate the risk of deep burns (>20 cm) and provide management recommendations. We synthesize the effects of drainage on peat moisture content and show how drainage and mining can weaken ecohydrological feedbacks in peatlands, making drained peatlands vulnerable to deep burns and carbon loss. We use bulk density and moisture data from burned, unburned and restored peatlands to evaluate the risk of deep burns under various conditions (differences in peat properties, extent of water table drop) using a new peat smouldering model. Climate change scenarios are shown to explore future risks of deep peat burning in extensively drained areas such as northern Europe. Combining modeling and experimental data we conclude that restoration can successfully lower the risk of deep burns if, for example, a new peat moss layer is established which will ensure a higher moisture content. Considering the large areas of drained and mined peatlands in the northern hemisphere, we will argue that restoration efforts are important to mitigate deep burns and carbon loss in peatlands.

  11. Contrasting growth responses of dominant peatland plants to warming and vegetation composition.

    PubMed

    Walker, Tom N; Ward, Susan E; Ostle, Nicholas J; Bardgett, Richard D

    2015-05-01

    There is growing recognition that changes in vegetation composition can strongly influence peatland carbon cycling, with potential feedbacks to future climate. Nevertheless, despite accelerated climate and vegetation change in this ecosystem, the growth responses of peatland plant species to combined warming and vegetation change are unknown. Here, we used a field warming and vegetation removal experiment to test the hypothesis that dominant species from the three plant functional types present (dwarf-shrubs: Calluna vulgaris; graminoids: Eriophorum vaginatum; bryophytes: Sphagnum capillifolium) contrast in their growth responses to warming and the presence or absence of other plant functional types. Warming was accomplished using open top chambers, which raised air temperature by approximately 0.35 °C, and we measured air and soil microclimate as potential mechanisms through which both experimental factors could influence growth. We found that only Calluna growth increased with experimental warming (by 20%), whereas the presence of dwarf-shrubs and bryophytes increased growth of Sphagnum (46%) and Eriophorum (20%), respectively. Sphagnum growth was also negatively related to soil temperature, which was lower when dwarf-shrubs were present. Dwarf-shrubs may therefore promote Sphagnum growth by cooling the peat surface. Conversely, the effect of bryophyte presence on Eriophorum growth was not related to any change in microclimate, suggesting other factors play a role. In conclusion, our findings reveal contrasting abiotic and biotic controls over dominant peatland plant growth, suggesting that community composition and carbon cycling could be modified by simultaneous climate and vegetation change. PMID:25687830

  12. Substrate lability and plant activity controls greenhouse gas release from Neotropical peatland

    NASA Astrophysics Data System (ADS)

    Sjogersten, Sofie; Hoyos, Jorge; Lomax, Barry; Turner, Ben; Wright, Emma

    2014-05-01

    Almost one third of global CO2 emissions resulting from land use change and substantial CH4 emissions originate from tropical peatlands. However, our understanding of the controls of CO2 and CH4 release from tropical peatlands are limited. The aim of this study was to investigate the role of peat lability and the activity of the vegetation on gas release using a combination of field and laboratory experiments. We demonstrated that peat lability constrained CH4 production to the surface peat under anaerobic conditions. The presence of plants shifted the C balance from a C source to a C sink with respect to CO2 while the activity of the root system strongly influenced CH4 emissions through its impact on soil O2 inputs. Both field and laboratory data suggest a coupling between the photosynthetic activity of the vegetation and the release of both CO2 and CH4 following the circadian rhythm of the dominant plant functional types. Forest clearance for agriculture resulted in elevated CH4 release, which we attribute in part to the cessation of root O2 inputs to the peat. We conclude that high emissions of CO2 and CH4 from forested tropical peatlands are likely driven by labile C inputs from the vegetation but that root O2 release may limit CH4 emissions.

  13. Temporal Changes in Photochemically Labile DOM and Implications for Carbon Budgets in Peatland Aquatic Systems

    NASA Astrophysics Data System (ADS)

    Pickard, A.

    2015-12-01

    Aquatic systems in peatland catchments are subject to high loading of dissolved organic matter (DOM) from surrounding terrestrial environments. However the significance of photochemical transformation of DOM in peatland carbon budgets remains poorly constrained. In this study UV irradiation experiments were conducted on water samples collected over one year from two contrasting systems in Scotland: a stream draining a peatland with high levels of DOM and a reservoir draining a peat catchment with low levels of DOM. Further samples were collected from the high DOM system during two storm events. After experimental exposure, optical and chemical analyses were employed to determine photochemical lability of the DOM pool. At both sites irradiation-induced decreases in dissolved organic carbon (DOC) as a percentage of the total carbon pool were greatest in winter, suggesting that DOM was depleted in photo-reactive molecules in summer. Seasonal variability in DOC was high at the stream site and was positively correlated with CO₂ and CO photoproduction (r2 = 0.81 and 0.83, respectively; p<0.05). Lignin phenol analyses indicate considerable contribution of peat to the DOM pool at the stream site, particularly during summer. Whilst DOC concentrations did not vary greatly during storm events, UV-Vis absorbance indicators did, signifying changing DOM source material from activation of different hydrological pathways. The most photo-reactive DOM occurred 5-10 hours after peak discharge, suggesting that storms replenish photochemically labile DOM in headwater streams. Conservative estimates using data from this study suggest that up to 7% of the DOM pool of peatland streams can be lost (primarily as CO₂ and CO) upon exposure to 8 hours of environmentally representative UV irradiation. Further investigation in field campaigns under natural UV exposure are underway to assess the importance of photodegradation of DOM as a loss pathway of carbon based gases from aquatic systems.

  14. Role of plant-mediated gas transport in CH4 emissions from Phragmites-dominated peatlands

    NASA Astrophysics Data System (ADS)

    van den Berg, Merit; Ingwersen, Joachim; van den Elzen, Eva; Lamers, Leon P. M.; Streck, Thilo

    2016-04-01

    A large part of the methane (CH4) produced in peatlands is directly oxidized and the extent of its oxidation depends on the gas transport pathway. In wetland ecosystems, CH4 can be transported from the soil to the atmosphere via diffusion, ebullition and via aerenchyma of roots and stems of vascular plants. Compared to other wetland plants, the very common species Phragmites australis (Common reed) appears to have a high ability to transport gases between the soil and atmosphere. The gas exchange within Phragmites plants takes place via convective flow through the culm, which is believed to be achieved by a humidity-induced pressure gradient and is more than 5-times as efficient as diffusion. By this mechanism, CH4 surpasses the upper (oxic) soil layers and therefore oxidation of CH4 may well be reduced. On the other hand, transport of oxygen in Phragmites plants tends to enhance O2concentration in the rhizosphere, which will foster CH4oxidation in deeper soil layers. It is therefore unknown whether humidity-induced convection leads to higher or lower overall CH4 emission in Phragmites, which is essential to understand their role in the emissions from these very common peatland types. To investigate whether this internal gas transport mechanism of reed promotes or reduces CH4 fluxes to the atmosphere, we conducted manipulative field experiments in a large Phragmites peatland in South-West Germany in October 2014 and July 2015. Using large chambers, we compared CH4 fluxes from intact plots, plots with cut reed, and plots with cut + sealed reed to exclude gas transport through the plants. Additionally, pore water samples from the plots were analyzed for possible changes in soil chemistry due to the change of oxygen transport into the soil by the treatments. Based on our results, we will explain the potential role of rhizosphere oxygenation and convective flow on CH4 emissions from Phragmites-dominated peatlands in relation to other environmental condition.

  15. Vegetation exerts a greater control on litter decomposition than climate warming in peatlands.

    PubMed

    Ward, Susan E; Orwin, Kate H; Ostle, Nicholas J; Briones, J I; Thomson, Bruce C; Griffiths, Robert I; Oakley, Simon; Quirk, Helen; Bardget, Richard D

    2015-01-01

    Historically, slow decomposition rates have resulted in the accumulation of large amounts of carbon in northern peatlands. Both climate warming and vegetation change can alter rates of decomposition, and hence affect rates of atmospheric CO2 exchange, with consequences for climate change feedbacks. Although warming and vegetation change are happening concurrently, little is known about their relative and interactive effects on decomposition processes. To test the effects of warming and vegetation change on decomposition rates, we placed litter of three dominant species (Calluna vulgaris, Eriophorum vaginatum, Hypnum jutlandicum) into a peatland field experiment that combined warming.with plant functional group removals, and measured mass loss over two years. To identify potential mechanisms behind effects, we also measured nutrient cycling and soil biota. We found that plant functional group removals exerted a stronger control over short-term litter decomposition than did approximately 1 degrees C warming, and that the plant removal effect depended on litter species identity. Specifically, rates of litter decomposition were faster when shrubs were removed from the plant community, and these effects were strongest for graminoid and bryophyte litter. Plant functional group removals also had strong effects on soil biota and nutrient cycling associated with decomposition, whereby shrub removal had cascading effects on soil fungal community composition, increased enchytraeid abundance, and increased rates of N mineralization. Our findings demonstrate that, in addition to litter quality, changes in vegetation composition play a significant role in regulating short-term litter decomposition and belowground communities in peatland, and that these impacts can be greater than moderate warming effects. Our findings, albeit from a relatively short-term study, highlight the need to consider both vegetation change and its impacts below ground alongside climatic effects when

  16. 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

  17. A field experiment and numerical modeling of a tracer at a gravel beach in Prince William Sound, Alaska

    NASA Astrophysics Data System (ADS)

    Guo, Qiaona; Li, Hailong; Boufadel, Michel C.; Liu, Jin

    2014-08-01

    Oil from the 1989 Exxon Valdez oil spill persists in many gravel beaches in Prince William Sound (Alaska, USA), despite great remedial efforts. A tracer study using lithium at a gravel beach on Knight Island, Prince William Sound, during the summer of 2008 is reported. The tracer injection and transport along a transect were simulated using the two-dimensional numerical model MARUN. Model results successfully reproduced the tracer concentrations observed at wells along the transect. A sensitivity analysis revealed that the estimated parameters are well determined. The simulated spatial distribution of tracer indicated that nutrients applied along the transect for bioremediation purposes would be washed to the sea very quickly (within a semi-diurnal tidal cycle) by virtue of the combination of the two-layered beach structure, the tidal fluctuation and the freshwater flow from inland. Thus, pore-water samples in the transect were found to be clean due to factors other than bioremediation. This may explain why the oil did not persist within the transect.

  18. A field experiment and numerical modeling of a tracer at a gravel beach in Prince William Sound, Alaska

    NASA Astrophysics Data System (ADS)

    Guo, Qiaona; Li, Hailong; Boufadel, Michel C.; Liu, Jin

    2014-12-01

    Oil from the 1989 Exxon Valdez oil spill persists in many gravel beaches in Prince William Sound (Alaska, USA), despite great remedial efforts. A tracer study using lithium at a gravel beach on Knight Island, Prince William Sound, during the summer of 2008 is reported. The tracer injection and transport along a transect were simulated using the two-dimensional numerical model MARUN. Model results successfully reproduced the tracer concentrations observed at wells along the transect. A sensitivity analysis revealed that the estimated parameters are well determined. The simulated spatial distribution of tracer indicated that nutrients applied along the transect for bioremediation purposes would be washed to the sea very quickly (within a semi-diurnal tidal cycle) by virtue of the combination of the two-layered beach structure, the tidal fluctuation and the freshwater flow from inland. Thus, pore-water samples in the transect were found to be clean due to factors other than bioremediation. This may explain why the oil did not persist within the transect.

  19. Contaminated sediment dynamics in peatland headwaters

    NASA Astrophysics Data System (ADS)

    Shuttleworth, Emma; Clay, Gareth; Evans, Martin; Hutchinson, Simon; Rothwell, James

    2016-04-01

    Peatlands are an important store of soil carbon, provide multiple ecosystem services, and when located in close proximity to urban and industrial areas, can also act as sinks of atmospherically deposited heavy metals. The near-surface layer of the blanket peats of the Peak District National Park, UK, is severely contaminated with high concentrations of anthropogenically derived, atmospherically deposited lead (Pb). These peats are severely degraded, and there is increasing concern that erosion is releasing considerable quantities of this legacy pollution into surface waters. Despite substantial research into Pb dynamics in peatlands formal description of the possible mechanisms of contaminated sediment mobilisation is limited. However, there is evidence to suggest that a substantial proportion of contaminated surface sediment may be redistributed elsewhere in the catchment. This study uses the Pb contamination stored near the peat's surface as a fingerprint to trace contaminated sediment dynamics and storage in three severely degraded headwater catchments. Erosion is exposing high concentrations of Pb on interfluve surfaces, and substantial amounts of reworked contaminated material are stored on other catchment surfaces (gully walls and floors). We propose a variety of mechanisms as controls of Pb release and storage on the different surfaces, including: (i) wind action on interfluves; (ii) the aspect of gully walls, and (iii) gully depth. Vegetation also plays an important role in retaining contaminated sediment on all surfaces.

  20. Upscaling methane emission hotspots in boreal peatlands

    NASA Astrophysics Data System (ADS)

    Cresto Aleina, Fabio; Runkle, Benjamin R. K.; Brücher, Tim; Kleinen, Thomas; Brovkin, Victor

    2016-03-01

    Upscaling the properties and effects of small-scale surface heterogeneities to larger scales is a challenging issue in land surface modeling. We developed a novel approach to upscale local methane emissions in a boreal peatland from the micro-topographic scale to the landscape scale. We based this new parameterization on the analysis of the water table pattern generated by the Hummock-Hollow model, a micro-topography resolving model for peatland hydrology. We introduce this parameterization of methane hotspots in a global model-like version of the Hummock-Hollow model that underestimates methane emissions. We tested the robustness of the parameterization by simulating methane emissions for the next century, forcing the model with three different RCP scenarios. The Hotspot parameterization, despite being calibrated for the 1976-2005 climatology, mimics the output of the micro-topography resolving model for all the simulated scenarios. The new approach bridges the scale gap of methane emissions between this version of the model and the configuration explicitly resolving micro-topography.

  1. Upscaling methane emission hotspots in boreal peatlands

    NASA Astrophysics Data System (ADS)

    Cresto Aleina, F.; Runkle, B. R. K.; Brücher, T.; Kleinen, T.; Brovkin, V.

    2015-10-01

    Upscaling the properties and the effects of small-scale surface heterogeneities to larger scales is a challenging issue in land surface modeling. We developed a novel approach to upscale local methane emissions in a boreal peatland from the micro-topographic scale to the landscape-scale. We based this new parameterization on the analysis of the water table pattern generated by the Hummock-Hollow model, a micro-topography resolving model for peatland hydrology. We introduce this parameterization of methane hotspots in a global model-like version of the Hummock-Hollow model, that underestimates methane emissions. We tested the robustness of the parameterization by simulating methane emissions for the next century forcing the model with three different RCP scenarios. The Hotspot parameterization, despite being calibrated for the 1976-2005 climatology, mimics the output of the micro-topography resolving model for all the simulated scenarios. The new approach bridges the scale gap of methane emissions between this version of the model and the configuration explicitly resolving micro-topography.

  2. Estimating Effects of Atmospheric Deposition and Peat Decomposition Processes on Mercury and Sulfur Accumulation and Retention in Northern Peatlands, Minnesota

    NASA Astrophysics Data System (ADS)

    Furman, O.; Nater, E.; Toner, B. M.; Sebestyen, S. D.; Tfaily, M. M.; Chanton, J.; Kolka, R. K.

    2013-12-01

    Northern peatland ecosystems play an important role in mercury (Hg) and sulfur (S) co-cycling. Peatlands are sinks for total Hg and sources for methyl Hg through the activity of sulfate-reducing bacteria. These ecosystems are vulnerable to environmental change, and projected changes in climate for the north-central U.S. have the potential to affect Hg and S stores and cycling in the subsurface, which may stimulate the release of bioaccumulative methyl Hg to receiving water bodies. SPRUCE (Spruce and Peatland Responses under Climate and Environmental change experiment) is an interdisciplinary study of the effects of temperature and enriched carbon dioxide on the responses of northern peatland ecosystems at the Marcell Experimental Forest, Minnesota. In the first year of SPRUCE, we are investigating Hg and S accumulation rates in 12-m diameter experimental plots on a black spruce bog before peatland heating experiments start in 2014. Understanding Hg and S accumulation rates and their retention mechanisms in the subsurface are needed in order to reconstruct historical trends in Hg and S deposition, and predict peatland responses to climate change. In this study, we will attempt to separate the effects of atmospheric deposition vs peat humification on Hg and S retention. As such, peat cores were sampled from sixteen experimental SPRUCE plots in August 2012. These 'Time 0' peat subsamples have been analyzed for total Hg, methyl Hg and total S, and bulk density as a function of depth (<2 m). In addition, peat subsamples have been analyzed for 14C and 13C to determine the age of peat and derive peat, Hg and S accumulation rates. Our preliminary results indicate that both total and methyl Hg, and total S concentrations reached the peak value in the 20-40 cm peat section, which is the transition zone between transiently oxidized acrotelm and permanently saturated anaerobic catotelm. Total and methyl Hg concentrations were several times lower in deeper profiles (>50 cm

  3. Exploring the limits of knowledge on boreal peatland development using a new model: the Holocene Peatland Model

    NASA Astrophysics Data System (ADS)

    Quillet, Anne; Garneau, Michelle; Frolking, Steve; Roulet, Nigel; Peng, Changhui

    2010-05-01

    The Holocene Peatland Model (HPM) (Frolking et al. 2009, Frolking et al. in prep.) is a recently developed tool integrating up-to-date knowledge on peatland dynamics that explores peatland development and carbon dynamics on a millennial timescale. HPM combines the water and carbon cycles with net primary production and peat decomposition and takes the multiple feedbacks into account. The model remains simple and few site-specific inputs are needed. HPM simulates the transient development of the peatland and delivers peat age, peat depth, peat composition, carbon accumulation and water table depth for each simulated year. Evaluating the ability of the model to reproduce peatland development can be achieved in several manners. Commonly one could choose to compare simulations results with observations from field data. However, we argue that the overall response of the model does not give much information about the value of the model design. Modelling of peatlands dynamics requires a lot of information regarding the behaviour of a peatland system within its environment (including allogenic changes in climate, hydrological conditions, nutrient availability or autogenic processes such as microtopographical effects). The actual state of knowledge does not cover all processes, interactions or feedbacks and a lot of peatland properties are neither well defined nor measured yet, so that estimates have been needed to build the model. The work presented here aims at analyzing the role of the model parameterization on the simulation results. To do so, a sensitivity analysis is performed with a Monte-Carlo analysis and with help of the GUI-HDMR software (Ziehn and Tomlin, 2009). This method ranks the parameters and combinations of them according to their influence on simulation results. The results will emphasize how the simulation is sensitive to the parameter values. First, the distribution of outputs gives insight into the possible responses of the simulation to HPM

  4. 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

  5. Peatlands as Dynamic Biogeochemical Ecotones: Elemental Concentrations, Stoichiometries and Accumulation in Peatland Soils of Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Moore, T. R.; Wang, M.; Talbot, J.; Riley, J. L.

    2015-12-01

    Peatlands act as biogeochemical interfaces between terrestrial and aquatic systems and are 'hotspots', particularly for carbon cycling and the accumulation of nutrients and other elements within the peat profile. This results in storage of substantial amounts of carbon, nutrients and metals, particularly in northern peatlands. Using a data base of over 400 peat profiles and 1700 individual peat samples from bog, fen and swamp sites in Ontario, Canada, we examine the profile concentrations of C, N, P, Ca, Mg, K, Hg, Pb, As, Cu, Mn, Zn, Fe and Al, and estimate the storage and accumulation of these elements. We show how these profiles, spatial patterns, stoichiometries and accumulation rates are controlled by biogeochemical processes and influenced by geochemical setting, hydrology, atmospheric input and pollution, and ecological and microbial transformations.

  6. Peatland classification of West Siberia based on Landsat imagery

    NASA Astrophysics Data System (ADS)

    Terentieva, I.; Glagolev, M.; Lapshina, E.; Maksyutov, S. S.

    2014-12-01

    Increasing interest in peatlands for prediction of environmental changes requires an understanding of its geographical distribution. West Siberia Plain is the biggest peatland area in Eurasia and is situated in the high latitudes experiencing enhanced rate of climate change. West Siberian taiga mires are important globally, accounting for about 12.5% of the global wetland area. A number of peatland maps of the West Siberia was developed in 1970s, but their accuracy is limited. Here we report the effort in mapping West Siberian peatlands using 30 m resolution Landsat imagery. As a first step, peatland classification scheme oriented on environmental parameter upscaling was developed. The overall workflow involves data pre-processing, training data collection, image classification on a scene-by-scene basis, regrouping of the derived classes into final peatland types and accuracy assessment. To avoid misclassification peatlands were distinguished from other landscapes using threshold method: for each scene, Green-Red Vegetation Indices was used for peatland masking and 5th channel was used for masking water bodies. Peatland image masks were made in Quantum GIS, filtered in MATLAB and then classified in Multispec (Purdue Research Foundation) using maximum likelihood algorithm of supervised classification method. Training sample selection was mostly based on spectral signatures due to limited ancillary and high-resolution image data. As an additional source of information, we applied our field knowledge resulting from more than 10 years of fieldwork in West Siberia summarized in an extensive dataset of botanical relevés, field photos, pH and electrical conductivity data from 40 test sites. After the classification procedure, discriminated spectral classes were generalized into 12 peatland types. Overall accuracy assessment was based on 439 randomly assigned test sites showing final map accuracy was 80%. Total peatland area was estimated at 73.0 Mha. Various ridge

  7. Net ecosystem production in a subarctic peatland

    SciTech Connect

    Luken, J.O.

    1984-01-01

    A mass balance approach was used to determine the rates of carbon storage in three areas of a subarctic bog near Fairbanks, Alaska (latitude 64/sup 0/52'N). Aboveground net primary production was 20.3, 74.2, and 77.4 gm/sup -2/yr/sup -1/ for nonvascular plants, the shrub and herb layer, and the tree layer of the bog forest, respectively. Aboveground net primary production was 83.7 and 58.2 g m/sup -2/yr/sup -1/ for nonvascular plants and the shrub and herb layer of the Andromeda bog, respectively, in the Carex lawns, aboveground net primary production was 194.9 and 111.7 g m/sup -2/yr/sup -1/ for nonvascular and vascular plants, respectively. Sphagnum mosses are important components of this peatbog ecosystem due to their high rates of net primary production and slow rates of decomposition. Experimental manipulations of light level, water table level, and nutrient availability indicated that terminal extension rates and volumetric density of the Sphagnum stands are controlled primarily by light and water table levels. An explanation of Sphagnum zonation in hummock-hollow complexes is presented which incorporates aspects of growth rate, stand morphology, and reproductive mode. Soil carbon dioxide efflux rates were measured in a number of different hummock-hollow microhabitats. Approximately 75% of the variance associated with soil respiration could be explained by regression equations with soil moisture and soil temperature as independent variables. Carbohydrate limitation of soil microbial populations was demonstrated in both laboratory and field experiments.

  8. Post-Fire Moss Recovery in Northern Peatlands: Separating the Effects of Species and Water Content on Moss Water Repellency

    NASA Astrophysics Data System (ADS)

    Moore, Paul; Lukenbach, Max; Waddington, James Michael

    2016-04-01

    Wildfire is the largest disturbance affecting peatlands, where northern peat reserves are becoming increasingly vulnerable to wildfire as climate change is projected to enhance the length and severity of the fire season. However, little is known about the spatio-temporal variability of post-fire recovery in these ecosystems. High water table positions after wildfire are critical to limit atmospheric carbon losses and enable the re-establishment of keystone peatland mosses (i.e., Sphagnum). Post-fire recovery of the moss surface in Sphagnum-feathermoss peatlands, however, has been shown to be limited where moss type and burn severity interact to result in a water repellent surface. While in situ measurements of moss water repellency in peatlands has been shown to be greater for feathermoss in both a burned and unburned state in comparison to Sphagnum moss, it is difficult to separate effects of water content from species. Consequently, we carried out a drying experiment in the lab where we compared the water repellency of two dominant peatland moss species, Sphagnum and feathermoss, for several burn severity classes as well as for unburned samples. The results suggest that water repellency in moss is primarily controlled by water content, where a sharp threshold exists at gravimetric water contents (GWC) lower than ~3 g g-1. While GWC is shown to be a strong predictor of water repellency, the effect is enhanced by combustion. Based on field GWC, we show that there are significant differences in the frequency distribution of near-surface GWC between moss type and burn severity. The differences in the distributions of field GWC are related to characteristic moisture retention curves of unburned samples measured in the lab, as well as morphological differences between moss type.

  9. Element transport to riverine system from forest-peatland complexes: ZOTTO footprint area

    NASA Astrophysics Data System (ADS)

    Prokushkin, A. S.; Pokrovsky, O. S.; Korets, M. A.; Karpenko, L. V.; Titov, S. V.; Schulze, E.-D.

    2012-04-01

    West Siberian peatlands store at least 70.2 Pg C and cover ca. 600,000 km2. The region experiences warming faster than the Arctic as a whole, so these peatlands receive large attention in last decades primarily because of their great potential for carbon release to the atmosphere through enhanced CO2 and/or CH4 gas emissions. The release of dissolved and/or particulate organic carbon to streams and rivers has emerged as an additional and crucial negative term in the carbon balance of peatlands throughout the world. The Ob' and Yenisey Rivers, draining Western Siberia Lowland en route to the Kara Sea, transport more dissolved organic carbon (DOC) than any other river of the Arctic Ocean basin. Thus, to predict the response of West Siberia peatlands to warming requires also exploring riverine element fluxes in the sense of (i) terrestrial sources and (ii) controlling mechanisms. Since 2006, the scientific and infrastructural platform of Zotino Tall Tower Observatory (ZOTTO) provides the unique opportunity to monitor and quantify the anticipated changes in biogeochemical cycles in this important region of the globe. Although the major efforts of ZOTTO are devoted to the atmospheric processes, the aim of this synergetic study was to link terrestrial ecosystems to aquatic chemistry with emphasis on carbon species. Remote sensing and field campaigns in footprint zone of ZOTTO have been done to investigate hydromorphic landscapes and link their properties to riverine element concentrations and export. In total, 12 bogs of ombrotrophic and minerotrophic genesis have been selected and comprehensively investigated for peat depth, peat layer elemental composition, biochemical composition (lignin CuO oxidation products), and carbon accumulation rates. Peat samples were analyzed for microbial composition and activity, and had their peat-forming plant species identified. In parallel, regular water sampling was performed on several rivers draining the research area to obtain the

  10. 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.

  11. Mechanisms controlling the production and transport of methane, carbon dioxide, and dissolved solutes within a boreal peatland. Progress report, July 15, 1992--July 14, 1993

    SciTech Connect

    Siegel, D.I.

    1993-06-24

    The role of freshwater peatlands in the global methane cycle remains uncertain. Field measurements of methane emissions tend to be highly variable across a peatland and exhibit sharp seasonal fluctuations. The process of extrapolating these variable measurements to regional estimates is further complicated by rudimentary knowledge of the environmental controls can the production and emissions of methane from peat. The distribution of methanogenesis within the peat profile will strongly influence the response of methane emissions to potential climatic changes. During the summers of 1990 and 1991 we conducted a study on the mechanisms for the production, transport, and storage of methane within the Glacial Lake Agassiz peatland region as the regional climate shifted from extreme drought to a period of normal rainfall. This natural experiment provided unexpected insights on the linkages among climate, hydrology, and the methane cycle in large peat basins. This report presents project progress for period July 15, 1992--July 14, 1993

  12. In situ sulphate stimulation of mercury methylation in a boreal peatland: Toward a link between acid rain and methylmercury contamination in remote environments

    NASA Astrophysics Data System (ADS)

    Branfireun, Brian A.; Roulet, Nigel T.; Kelly, Carol. A.; Rudd, John W. M.

    1999-09-01

    Recent studies have found that "pristine" peatlands have high peat and pore water methylmercury (MeHg) concentrations and that peatlands may act as large sources of MeHg to the downstream aquatic system, depending upon the degree of hydrologie connectivity and catchment physiography. Sulphate-reducing bacteria have been implicated as principal methylators of inorganic mercury in many environments with previous research focused primarily on mercury methylation in aquatic sediments. Experiments in a poor fen in the Experimental Lakes Area, northwestern Ontario, Canada, demonstrated that the in situ addition of sulphate to peat and peat pore water resulted in a significant increase in pore water MeHg concentrations. As peatlands cover a large area of the Northern Hemisphere, this finding has potentially far ranging implications for the global mercury cycle, particularly in areas impacted by anthropogenically derived sulphate where the methylmercury fraction of total mercury species may be much larger than in nonimpacted environments.

  13. Bedrock topography beneath the Red Lake peatlands

    SciTech Connect

    Miller, P.; Shaw, G.H. . Geology Dept.); Glaser, P. . Limnological Research Center); Siegel, D. . Dept. of Geology)

    1992-01-01

    Detailed hydrologic investigations of peat landforms in the Red Lake Peatlands have revealed that groundwater flow is significantly related to the type of landform and vegetation community present at a given site. Hydrogeologic modeling of shallow groundwater systems suggests that bedrock topography is an important, perhaps the vital, boundary condition controlling groundwater flow. Determination of depth to bedrock beneath different peat landforms is necessary to test the hydrogeologic models and obtain a better understanding of the processes which produce them. Direct determination of bedrock depth in peatlands is hampered by the difficult conditions and high costs of boring. In addition, environmental impacts from boring activities would probably be substantial in these sensitive ecosystems. Shallow seismic methods appear to be the most promising approach to obtain the necessary data. Unfortunately the 2+ meters of peat covering Lake Agassiz sediments overlying the bedrock is not only a poor substrate for geophone emplacement, but is a strong attenuator of seismic waves. These difficulties have been overcome by constructing a tool which allows the geophones to be emplaced beneath the peat and into the top of the sediments. The shotgun cartridge source is also located beneath the peat. This combination results in very good seismic records, far better than those possible with surface sources and geophones. The results from a preliminary survey along a 600m line show that there are significant variations in bedrock topography below the peat. In a distance of less than 500m, depth to bedrock changes by about 30%, from about 55m to about 40m. This is similar to variations indicated by the models.

  14. Processes responding to restoration in forestry-drained peatlands

    NASA Astrophysics Data System (ADS)

    Tarvainen, Oili; Laine, Anna; Tolvanen, Anne

    2014-05-01

    Almost one third, nearly 100 000 km2, of the total land area is covered by peatlands in Finland, which is a higher relative cover than in any other country in the world. Over a half of the peatland area has been drained for forestry, and many invaluable wetland habitat types are severely degraded. Restoration of forestry-drained peatlands is a relatively new measure, and long term results are still relatively scarce. Reinstating the ecological function with its feedback cycles can be a slow and gradual process. Nevertheless, since forestry-drained peatlands are not destroyed habitats in terms of their ecosystem functions, they can be expected to be reinstated through the returning of the crucial element, the high water-table level and its natural variability. To evaluate the development of peatland function and structure after restoration, indicators which respond at different speed to restoration are therefore useful. Vegetation indicators are commonly assessed to indicate restoration progress, but they can be slow to respond. Changes in the mineralization and decomposition rates may indicate sooner, if processes typical for undrained peatlands are initiating after restoration. However, despite the increasing amount of information on the vegetation structure after restoring forestry-drained peatlands, there is no sufficient information on the ecological processes, which may be reasons behind the existing difference between restored and pristine peatlands. Information on the ecological processes and the speed of their recovery helps to evaluate whether the restored peatlands have turned their development towards natural situation, despite that the structure does not yet show sufficient recovery. We studied how restoration affects the hydrology, peat forming processes, and vegetation in boreal fen type of peatlands. Fens drained for forestry 30 - 40 year earlier were restored in northern Finland in 2007 by harvesting trees and by damming and filling ditches. After

  15. Nitrogen removal in Northern peatlands treating mine wastewaters

    NASA Astrophysics Data System (ADS)

    Palmer, Katharina; Karlsson, Teemu; Turunen, Kaisa; Liisa Räisänen, Marja; Backnäs, Soile

    2015-04-01

    Natural peatlands can be used as passive purification systems for mine wastewaters. These treatment peatlands are well-suited for passive water treatment as they delay the flow of water, and provide a large filtration network with many adsorptive surfaces on plant roots or soil particles. They have been shown to remove efficiently harmful metals and metalloids from mine waters due to variety of chemical, physical and biological processes such as adsorption, precipitation, sedimentation, oxidation and reduction reactions, as well as plant uptake. Many factors affect the removal efficiency such as inflow water quality, wetland hydrology, system pH, redox potential and temperature, the nature of the predominating purification processes, and the presence of other components such as salts. However, less attention has been paid to nitrogen (N) removal in peatlands. Thus, this study aimed to assess the efficiency of N removal and seasonal variation in the removal rate in two treatment peatlands treating mine dewatering waters and process effluent waters. Water sampling from treatment peatland inflow and outflow waters as well as pore waters in peatland were conducted multiple times during 2012-2014. Water samples were analysed for total N, nitrate-N and ammonium-N. Additionally, an YSI EXO2 device was used for continuous nitrate monitoring of waters discharged from treatment peatlands to the recipient river during summer 2014. The results showed that the oxic conditions in upper peat layer and microbial activity in treatment peatlands allowed the efficient oxidation of ammonium-N to nitrite-N and further to nitrate-N during summer time. However, the slow denitrification rate restricts the N removal as not all of the nitrate produced during nitrification is denitrified. In summer time, the removal rate of total N varied between 30-99 % being highest in late summer. N removal was clearly higher for treatment peatland treating process effluent waters than for peatland

  16. Alaska volcanoes guidebook for teachers

    USGS Publications Warehouse

    Adleman, Jennifer N.

    2011-01-01

    Alaska’s volcanoes, like its abundant glaciers, charismatic wildlife, and wild expanses inspire and ignite scientific curiosity and generate an ever-growing source of questions for students in Alaska and throughout the world. Alaska is home to more than 140 volcanoes, which have been active over the last 2 million years. About 90 of these volcanoes have been active within the last 10,000 years and more than 50 of these have been active since about 1700. The volcanoes in Alaska make up well over three-quarters of volcanoes in the United States that have erupted in the last 200 years. In fact, Alaska’s volcanoes erupt so frequently that it is almost guaranteed that an Alaskan will experience a volcanic eruption in his or her lifetime, and it is likely they will experience more than one. It is hard to imagine a better place for students to explore active volcanism and to understand volcanic hazards, phenomena, and global impacts. Previously developed teachers’ guidebooks with an emphasis on the volcanoes in Hawaii Volcanoes National Park (Mattox, 1994) and Mount Rainier National Park in the Cascade Range (Driedger and others, 2005) provide place-based resources and activities for use in other volcanic regions in the United States. Along the lines of this tradition, this guidebook serves to provide locally relevant and useful resources and activities for the exploration of numerous and truly unique volcanic landscapes in Alaska. This guidebook provides supplemental teaching materials to be used by Alaskan students who will be inspired to become educated and prepared for inevitable future volcanic activity in Alaska. The lessons and activities in this guidebook are meant to supplement and enhance existing science content already being taught in grade levels 6–12. Correlations with Alaska State Science Standards and Grade Level Expectations adopted by the Alaska State Department of Education and Early Development (2006) for grades six through eleven are listed at

  17. Alaska's Economy: What's Ahead?

    ERIC Educational Resources Information Center

    Alaska Review of Social and Economic Conditions, 1987

    1987-01-01

    This review describes Alaska's economic boom of the early 1980s, the current recession, and economic projections for the 1990s. Alaska's economy is largely influenced by oil prices, since petroleum revenues make up 80% of the state government's unrestricted general fund revenues. Expansive state spending was responsible for most of Alaska's…

  18. Alaska Natives & the Land.

    ERIC Educational Resources Information Center

    Arnold, Robert D.; And Others

    Pursuant to the Native land claims within Alaska, this compilation of background data and interpretive materials relevant to a fair resolution of the Alaska Native problem seeks to record data and information on the Native peoples; the land and resources of Alaska and their uses by the people in the past and present; land ownership; and future…

  19. Carbon accumulation of tropical peatlands over millennia: a modeling approach.

    PubMed

    Kurnianto, Sofyan; Warren, Matthew; Talbot, Julie; Kauffman, Boone; Murdiyarso, Daniel; Frolking, Steve

    2015-01-01

    Tropical peatlands cover an estimated 440,000 km2 (~10% of global peatland area) and are significant in the global carbon cycle by storing about 40-90 Gt C in peat. Over the past several decades, tropical peatlands have experienced high rates of deforestation and conversion, which is often associated with lowering the water table and peat burning, releasing large amounts of carbon stored in peat to the atmosphere. We present the first model of long-term carbon accumulation in tropical peatlands by modifying the Holocene Peat Model (HPM), which has been successfully applied to northern temperate peatlands. Tropical HPM (HPMTrop) is a one-dimensional, nonlinear, dynamic model with a monthly time step that simulates peat mass remaining in annual peat cohorts over millennia as a balance between monthly vegetation inputs (litter) and monthly decomposition. Key model parameters were based on published data on vegetation characteristics, including net primary production partitioned into leaves, wood, and roots; and initial litter decomposition rates. HPMTrop outputs are generally consistent with field observations from Indonesia. Simulated long-term carbon accumulation rates for 11,000-year-old inland, and 5000-year-old coastal peatlands were about 0.3 and 0.59 Mg C ha(-1) yr(-1), and the resulting peat carbon stocks at the end of the 11,000-year and 5000-year simulations were 3300 and 2900 Mg C ha(-1), respectively. The simulated carbon loss caused by coastal peat swamp forest conversion into oil palm plantation with periodic burning was 1400 Mg C ha(-1) over 100 years, which is equivalent to ~2900 years of C accumulation in a hectare of coastal peatlands. PMID:25044171

  20. Fire and Microtopography in Peatlands: Feedbacks and Carbon Dynamics

    NASA Astrophysics Data System (ADS)

    Benscoter, B.; Turetsky, M. R.

    2011-12-01

    Fire is the dominant natural disturbance in peatland ecosystems. Over the past decade, peat fires have emerged as an important issue for global climate change, human health, and economic loss, largely due to the extreme peat fire events in Indonesia and Russia that severely impacted metropolitan areas and social infrastructure. However, the impact and importance of fire in peatland ecosystems are more far-reaching. Combustion of vegetation and soil organic matter releases an average of 2.2 kg C m-2 to the atmosphere, primarily as CO2, as well as a number of potentially harmful emissions such as fine particulate matter and mercury. Additionally, while peatlands are generally considered to be net sinks of atmospheric carbon, the removal of living vegetation by combustion halts primary production following fire resulting in a net loss of ecosystem carbon to the atmosphere for several years. The recovery of carbon sink function is linked to plant community succession and development, which can vary based on combustion severity and the resulting post-fire microhabitat conditions. Microtopography has a strong influence on fire behavior and combustion severity during peatland wildfires. In boreal continental peatlands, combustion severity is typically greatest in low-lying hollows while raised hummocks are often lightly burned or unburned. The cross-scale influence of microtopography on landscape fire behavior is due to differences in plant community composition between microforms. The physiological and ecohydrological differences among plant communities result in spatial patterns in fuel availability and condition, influencing the spread, severity, and type of combustion over local to landscape scales. In addition to heterogeneous combustion loss of soil carbon, this differential fire behavior creates variability in post-fire microhabitat conditions, resulting in differences in post-fire vegetation succession and carbon exchange trajectories. These immediate and legacy

  1. Towards a Global High Resolution Peatland Map in 2020

    NASA Astrophysics Data System (ADS)

    Barthelmes, Alexandra; Barthelmes, Karen-Doreen; Joosten, Hans; Dommain, Rene; Margalef, Olga

    2015-04-01

    Some 3% of land area on planet Earth (approx. 4 million km2) is covered by peatlands. About 10% (~ 0.3 % of the land area) are drained and responsible for a disproportional 5 % of the global anthropogenic CO2 emissions (Victoria et al., 2012). Additionally, peatland drainage and degradation lead to land subsidence, soil degradation, water pollution, and enhanced susceptibility to fire (Holden et al., 2004; Joosten et al., 2012). The global importance of peatlands for carbon storage and climate change mitigation has currently been recognized in international policy - since 2008 organic soils are subject of discussion in the UN Framework Convention on Climate Change (UNFCCC) (Joosten, 2011). In May 2013 the European Parliament decided that the global post 2020 climate agreement should include the obligation to report emissions and removals from peatland drainage and rewetting. Implementation of such program, however, necessitates the rapid availability of reliable, comprehensive, high resolution, spatially explicit data on the extent and status of peatlands. For many reporting countries this requires an innovation in peatland mapping, i.e. the better and integrative use of novel, but already available methods and technologies. We developed an approach that links various science networks, methodologies and data bases, including those of peatland/landscape ecology for understanding where and how peatlands may occur, those of remote sensing for identifying possible locations, and those of pedology (legacy soil maps) and (palaeo-)ecology for ground truthing. Such integration of old field data, specialized knowledge, and modern RS and GIS technologies enables acquiring a rapid, comprehensive, detailed and rather reliable overview, even on a continental scale. We illustrate this approach with a high resolution overview of peatland distribution, area, status and greenhouse gas fluxes e.g. for the East African countries Rwanda, Burundi, Uganda and Zambia. Furthermore, we

  2. Towards a Global High Resolution Peatland Map in 2020

    NASA Astrophysics Data System (ADS)

    Barthelmes, Alexandra; Barthelmes, Karen-Doreen; Dommain, Rene; Margalef, Olga; Joosten, Hans

    2014-05-01

    Some 3% of land area on planet Earth (approx. 4 million km2) is covered by peatlands. About 10% (~ 0.3 % of the land area) are drained and responsible for a disproportional 5 % of the global anthropogenic CO2 emissions (Victoria et al., 2012). Additionally, peatland drainage and degradation lead to land subsidence, soil degradation, water pollution, and enhanced susceptibility to fire (Holden et al., 2004; Joosten et al., 2012). The global importance of peatlands for carbon storage and climate change mitigation has only recently been recognized in international policy - only since 2008 organic soils are subject of discussion in the UN Framework Convention on Climate Change (UNFCCC) (Joosten, 2011). In May 2013 the European Parliament decided that the global post 2020 climate agreement should include the obligation to report emissions and removals from peatland drainage and rewetting. Implementation of such program, however, necessitates the rapid availability of reliable, comprehensive, high resolution, spatially explicit data on the extent and status of peatlands. For many reporting countries this requires an innovation in peatland mapping, i.e. the better and integrative use of novel, but already available methods and technologies. We developed an approach that links various science networks, methodologies and data bases, including those of peatland/landscape ecology for understanding where and how peatlands may occur, those of remote sensing for identifying possible locations, and those of pedology (legacy soil maps) and (palaeo-)ecology for ground truthing. Such integration of old field data, specialized knowledge, and modern RS and GIS technologies enables acquiring a rapid, comprehensive, detailed and rather reliable overview, even on a continental scale. We illustrate this approach with a high resolution overview of peatland distribution, area, status and greenhouse gas fluxes for East Africa (including the Horn of Africa, the African Great Lakes region and

  3. In the line of fire: the peatlands of Southeast Asia.

    PubMed

    Page, S E; Hooijer, A

    2016-06-01

    Peatlands are a significant component of the global carbon (C) cycle, yet despite their role as a long-term C sink throughout the Holocene, they are increasingly vulnerable to destabilization. Nowhere is this shift from sink to source happening more rapidly than in Southeast Asia, and nowhere else are the combined pressures of land-use change and fire on peatland ecosystem C dynamics more evident nor the consequences more apparent. This review focuses on the peatlands of this region, tracing the link between deforestation and drainage and accelerating C emissions arising from peat mineralization and fire. It focuses on the implications of the recent increase in fire occurrence for air quality, human health, ecosystem resilience and the global C cycle. The scale and controls on peat-driven C emissions are addressed, noting that although fires cause large, temporary peaks in C flux to the atmosphere, year-round emissions from peat mineralization are of a similar magnitude. The review concludes by advocating land management options to reduce future fire risk as part of wider peatland management strategies, while also proposing that this region's peat fire dynamic could become increasingly relevant to northern peatlands in a warming world.This article is part of the themed issue 'The interaction of fire and mankind'. PMID:27216508

  4. Quality of runoff from Minnesota peatlands. I. A characterization

    SciTech Connect

    Clausen, J.C.; Brooks, K.N.

    1983-10-01

    The likelihood of expanded use of Minnesota's 3 million hectares of peatlands prompted the state to initiate a hydrologic study to characterize these groundwater-linked systems. Determining the quality of stream flow from these peatlands was an integral part of the study. Peatlands could be differentiated either on the basis of stream flow quality or on soil-vegetation characteristics. The quality of stream flow from 45 undisturbed peatlands was characterized by collecting samples five times in 1979-1980 and analyzing them for 27 water quality characteristics. Runoff pH, specific conductance, alkalinity, calcium, and magnesium were used to classify the peatlands as bog, transition, or fen. Bog runoff was lower (..cap alpha.. = 0.05) in pH, calcium, sodium, manganese, and ammonia nitrogen than fen runoff, but was higher in acidity, color, aluminum, humic and fulvic acid, and chemical oxygen demand than fen runoff. Bogs had more fibric peat of a lower pH than fens; fens exhibited tall woody shrubs which were virtually absent on bogs. 5 references, 3 figures, 3 tables.

  5. Mercury cycling in boreal ecosystems: The long-term effect of acid rain constituents on peatland pore water methylmercury concentrations

    NASA Astrophysics Data System (ADS)

    Branfireun, Brian A.; Bishop, Kevin; Roulet, Nigel T.; Granberg, Gunnar; Nilsson, Mats

    Sulphate-reducing bacteria have been identified as primary methylators of mercury (Hg) in the laboratory and in field investigations. However, no studies have investigated the effect of long-term deposition of sulphate on methylmercury (MeHg) dynamics in peatlands, which are known to be significant sources of MeHg to downstream waters in the boreal forest zone. As an ancillary experiment to a larger project investigating the effects of acid rain constituents on peatland carbon dynamics, the influence of experimentally elevated Na2SO4 and/or NH4NO3 deposition on peat pore water MeHg concentrations was determined using a simple mesocosm experimental design. After three years, additions of S in amounts equivalent to the 1980s dry and wet deposition in Southern Sweden resulted in peat pore water MeHg concentrations up to six times above background levels. Elevated N loads had no effect on pore water MeHg concentrations.

  6. 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.

  7. Hydrogeologic setting of the Glacial Lake Agassiz Peatlands, northern Minnesota

    USGS Publications Warehouse

    Siegel, Donald I.

    1981-01-01

    Seven test holes drilled in the Glacial Lake Agassiz Peatlands indicate that the thickness of surficial materials along a north-south traverse parallel to Minnesota Highway 72 ranges from 163 feet near Blackduck, Minnesota to 57 feet about 3 miles south of Upper Red Lake. Lenses of sand and gravel occur immediately above bedrock on the Itasca moraine and are interbedded with lake clay and till under the peatlands. Vertical head gradients measured in a piezometer nest near Blackduck on the moraine are downward, indicative of recharge to the regional ground-water-flow system. Vertical head gradients are upward in a piezometer nest on a sand beach ridge in the peatlands 12 miles north of Upper Red Lake. Numerical sectional models indicate that this discharge probably comes from local flow systems recharged from ground-water mounds located under large raised bogs.

  8. Carbon and nitrogen dynamics in mesocosms of five different European peatlands

    NASA Astrophysics Data System (ADS)

    Blodau, Christian; Zajac, Katarzyna

    2015-04-01

    Elevated nitrogen (N) deposition, a key growth limiting nutrient in ombrotrophic peatlands, can cause various shifts in peatland N cycling. Quantification of N transformation rates and fluxes within peatlands that are induced by long-term N deposition is crucial for understanding the mechanisms and robustness of N retention. Using a 15N labeled tracer under steady state conditions at two water table levels, we investigated the fate of N in mesocosms from five European peatlands, which have a history of differing long-term N load. Peat contained the largest N pool, followed by Sphagnum (0 - 5 cm), shrubs, graminoids and the dissolved pool. We found a decline of N recovery from the peat and an increase of N recovery from shrubs and the dissolved pool across the N deposition gradient. Sphagnum mosses not only intercepted large amounts of 15N in the mesocosms (0.2 - 0.35 mg g-1) but they also retained the tracer most effectively relative to their biomass. Polluted sites (Lille Vildmose, Frölichshaier Sattelmoor) contained the largest dissolved nitrogen pools and the highest nitrate concentrations. At the same time the recoveries of their Sphagnum pools were in the range of the recovery recorded for the Sphagnum layer from the 'clean' site (Degerö Stormyr). Our experiment shows that a decline in N retention at levels above ca. 1.5 g m-2 yr-1, as expressed by elevated near-surface peat N content and increased dissolved N concentrations, might not be an evidence for Sphagnum saturation. As long as N is required for the synthesis of biomass Sphagnum species can thrive even at strongly elevated long-term N loads. A change in WT position from -28 to -8 cm influenced CO2 fluxes from mesocosms only to a small degree, which implies that small changes in water table position may be less important in controlling CO2 exchange with the atmosphere than often assumed. Although water table rise was a main driver for increase of methane emissions in all cores, short time lags (3

  9. 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

  10. Properties of peatlands in relation to environmental factors in Minnesota

    SciTech Connect

    Swanson, D.K.

    1988-01-01

    The relationship of peatland morphology and distribution to environmental factors was investigated in northern and central Minnesota by field sampling of vegetation, soils, and water, and by remote sensing. Maps of peatlands made by machine classification of Landsat data six classes matched field data in 56% of all cases; maps drawn by hand on 1:80,000 scale aerial photographs were 72% correct. Peatland sites fall into two natural groups: ombrotrophic (bogs; pH less than 4.4) and minerotrophic (fens and swamps: pH 4.4 or more and usually greater than 5.6). The presence of certain common vascular-plant taxa can be used to classify sites into these trophic classes with over 90% accuracy. The structure of peatland vegetation is controlled by the soil-water regime, the disturbance history, and, to a less degree, by trophic conditions. Sites that have relatively well-aerated soils and have not been recently disturbed support dense forests. Vegetation structure is weakly related to the degree of decomposition of peat; hence vegetation is a poor indicator for taxonomic units of organic soils. Peatlands are common in Minnesota on surfaces glaciated during the Wisconsin Stage and where the mean annual potential evapotranspiration roughly equals or exceeds the mean annual precipitation. Bogs occur most often on sites where a high water table can be maintained without groundwater discharge, such as in depressions on low-permeability substrates and near local watershed divides on plains. Fens apparently occur in or below areas of groundwater discharge. Swamps (densely forested minerotrophic peatlands) occur in a wide variety of settings where the soil is aerated during the growing season.

  11. Elemental, stable isotopic and biochemical characterization of soil organic matter alteration across a natural peatland gradient

    NASA Astrophysics Data System (ADS)

    Cowie, G.; Mowbray, S.; Belyea, L.; Laing, C.; Allton, K.; Abbott, G.; Muhammad, A.

    2010-12-01

    Northern peatlands store around one third of global soil C and thus represent a key reservoir. To elucidate how these systems might respond to climate change, field- and laboratory-based experimental incubation studies are being conducted at sites across a natural peatland gradient in the boreonemoral zone of central Sweden (Ryggmossen). The site comprises four successional stages, from edge to centre; Swamp Forest (SF), Lagg Fen (LF), Bog Margin (BM) and Bog Plateau (BP). The well-preserved succession shows strong decreases in mineral cations and pH, and distinct changes in vegetation and water-table depth. As an underpinning to these experiments, comprehensive characterization of natural soil organic matter (SOM) alteration has been carried out through detailed analyses of vegetation and downcore profiles at contrasting topographic sites (hummock vs hollow) in each of the four locations. As illustrated in Figure 1, while some similarities occur in downcore trends, contrasts are observed in C and N elemental and stable isotopic compositions, between stages and, in some cases, between microtopographic settings. Downcore trends and intersite differences are also observed in biochemical yields and molecular composition (carbohydrates, amino acids, phenols, lipids and D/L amino acid ratios). These reflect SOM decay and alteration combined with the effects of contrasting hydrologic, redox and nutrient regimes and differing vegetation and microbial inputs at each of the study sites. Multivariate analysis is used to to elucidate compositional patterns that characterize and delineate progressive SOM decay, specific vegetation types, and the effects of contrasting environmental conditions at the different sites. Figure 1. A. Organic carbon content (wt %), B. Atomic ratio of organic C to total N, C. Stable C isotopic composition of organic C (d13Corg), and D. Stable N isotopic composition of total nitrogen (d15N), all for core profiles from contrasting settings (hummock and

  12. Hydrogeological controls on post-fire moss recovery in peatlands

    NASA Astrophysics Data System (ADS)

    Lukenbach, M. C.; Devito, K. J.; Kettridge, N.; Petrone, R. M.; Waddington, J. M.

    2015-11-01

    Wildfire is the largest disturbance affecting boreal peatlands, however, little is known about the controls on post-fire peatland vegetation recovery. While small-scale variation in burn severity can reduce post-fire moss water availability, high water table (WT) positions following wildfire are also critical to enable the re-establishment of keystone peatland mosses (i.e. Sphagnum). Thus, post-fire moss water availability is also likely a function of landscape-scale controls on peatland WT dynamics, specifically, connectivity to groundwater flow systems (i.e. hydrogeological setting). For this reason, we assessed the interacting controls of hydrogeological setting and burn severity on post-fire moss water availability in three burned, Sphagnum-dominated peatlands in Alberta's Boreal Plains. At all sites, variation in burn severity resulted in a dichotomy between post-fire surface covers that: (1) exhibited low water availability, regardless of WT position, and had minimal (<5%) moss re-establishment (i.e. lightly burned feather mosses and severely burned Sphagnum fuscum) or (2) exhibited high water availability, depending on WT position, and had substantial (>50%) moss re-establishment (i.e. lightly burned S. fuscum and where depth of burn was >0.05 m). Notably, hydrogeological setting influenced the spatial coverage of these post-fire surface covers by influencing pre-fire WTs and stand characteristics (e.g., shading). Because feather moss cover is controlled by tree shading, lightly burned feather mosses were ubiquitous (>25%) in drier peatlands (deeper pre-fire WTs) that were densely treed and had little connection to large groundwater flow systems. Moreover, hydrogeological setting also controlled post-fire WT positions, thereby affecting moss re-establishment in post-fire surface covers that were dependent on WT position (e.g., lightly burned S. fuscum). Accordingly, higher recolonization rates were observed in a peatland located in a groundwater flow through

  13. Alaska Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Murray, Tom; Read, Cyrus

    2008-01-01

    Steam plume from the 2006 eruption of Augustine volcano in Cook Inlet, Alaska. Explosive ash-producing eruptions from Alaska's 40+ historically active volcanoes pose hazards to aviation, including commercial aircraft flying the busy North Pacific routes between North America and Asia. The Alaska Volcano Observatory (AVO) monitors these volcanoes to provide forecasts of eruptive activity. AVO is a joint program of the U.S. Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Augustine volcano and AVO at http://www.avo.alaska.edu.

  14. National Indian Education Study 2011: The Educational Experiences of American Indian and Alaska Native Students at Grades 4 and 8. NCES 2012-466

    ERIC Educational Resources Information Center

    National Center for Education Statistics, 2012

    2012-01-01

    Since 2005, the National Indian Education Study (NIES) has provided educators, policymakers, and the public with information about the background and academic performance of fourth- and eighth-grade American Indian and Alaska Native (AI/AN) students in the United States. NIES was administered in 2005, 2007, 2009, and 2011 as part of the National…

  15. Recent acceleration of biomass burning and carbon losses in Alaskan forests and peatlands

    USGS Publications Warehouse

    Turetsky, M.R.; Kane, E.S.; Harden, J.W.; Ottmar, R.D.; Manies, K.L.; Hoy, E.; Kasischke, E.S.

    2011-01-01

    Climate change has increased the area affected by forest fires each year in boreal North America. Increases in burned area and fire frequency are expected to stimulate boreal carbon losses. However, the impact of wildfires on carbon emissions is also affected by the severity of burning. How climate change influences the severity of biomass burning has proved difficult to assess. Here, we examined the depth of ground-layer combustion in 178 sites dominated by black spruce in Alaska, using data collected from 31 fire events between 1983 and 2005. We show that the depth of burning increased as the fire season progressed when the annual area burned was small. However, deep burning occurred throughout the fire season when the annual area burned was large. Depth of burning increased late in the fire season in upland forests, but not in peatland and permafrost sites. Simulations of wildfire-induced carbon losses from Alaskan black spruce stands over the past 60 years suggest that ground-layer combustion has accelerated regional carbon losses over the past decade, owing to increases in burn area and late-season burning. As a result, soils in these black spruce stands have become a net source of carbon to the atmosphere, with carbon emissions far exceeding decadal uptake.

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

    USGS Publications Warehouse

    Klapstein, Sara J.; Turetsky, Merritt R.; McGuire, Anthony; 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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.

  18. Hydrogeological controls on post-fire moss recovery in peatlands

    NASA Astrophysics Data System (ADS)

    Lukenbach, Max; Devito, Kevin; Kettridge, Nicholas; Petrone, Richard; Waddington, James

    2015-04-01

    Wildfire is the largest disturbance affecting peatlands, however, little is known about the spatiotemporal variability of post-fire recovery in these ecosystems. High water table (WT) positions after wildfire are critical to limit atmospheric carbon losses and enable the re-establishment of keystone peatland mosses (i.e. Sphagnum). While small-scale variation in burn severity can reduce capillary flow from the WT and lead to a dry surface after fire, steep WT declines can also limit post-fire moss water availability. As such, post-fire moss water availability is also a function of large-scale controls on peatland WT dynamics, specifically, connectivity to groundwater flow systems (i.e. hydrogeological setting). For this reason, we assessed the interacting controls of hydrogeological setting and burn severity on post-fire moss water availability by measuring peatland WTs, soil tension (Ψ) and surface volumetric moisture content (θ) in three burned, Sphagnum-dominated peatlands located in different hydrogeological settings for three years following wildfire. The effect of burn severity on post-fire moss water availability did not vary with hydrogeological setting, however, the spatial coverage of high and low burn severity did vary between peatlands located in different hydrogeological settings due to its influence on pre-fire fuel loads and species cover. Locations covered by S. fuscum prior to fire exhibited decreasing post-fire water availability with increasing burn severity. In contrast, the lowest water availability (Ψ > 400 cm, θ < 0.02) was observed in feather mosses that underwent low burn severity (residual branches identifiable). Where depth of burn was > 0.05 m (high burn severity) and pre-fire species were not identifiable, water availability was highest (Ψ < 90 cm). Where burn severity did not limit water availability through a reduction of capillary flow, depth to WT (and therefore hydrogeological setting) played a large role in affecting post

  19. Factors controlling fluxes of volatile sulfur compounds in Sphagnum peatlands. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Demello, William Zamboni

    1992-01-01

    Exchange of DMS and OCS between the surface of Sphagnum peatlands and the atmosphere were measured with dynamic (S-free sweep air) and static enclosures. DMS emission rates determined by both methods were comparable. The dynamic method provided positive OCS flux rates (emission) for measurements performed at sites containing Sphagnum. Conversely, data from the static method indicated that OCS was consumed from the atmosphere. Short and long-term impacts of increased S deposition on fluxes of volatile S compounds (VSC's) from Sphagnum peatlands were investigated in a poor fen (Mire 239) at the Experimental Lakes Area, Ontario, Canada. Additional experiments were conducted in a poor fen (Sallie's Fen in Barrington, NH, USA). At Mire 239, emissions of VSC's were monitored, before and after acidification, at control and experimental sections within two major physiographic areas of the mire (oligotrophic and minerotrophic). DMS was the predominant VSC released from Mire 239 and varied largely with time and space. Sulfur addition did not affect DMS emissions in a period of hours to a few days. DMS emissions in the experimental oligotrophic area of the mire was approximately 3-fold greater than in the control oligotrophic area, and approximately 10-fold greater than in the minerotrophic zones. These differences could be due to a combination of differences in types of vegetation, nutritional status, and S input. At Sallie's Fen, DMS fluxes were not significantly affected by sulfate amendments, while DMS and MSH concentrations increased greatly with time in the top 10 cm of the peat column. The major environmental factors controlling fluxes of DMS in a Sphagnum-dominated peatland were investigated in Sallie's Fen, NH. DMS emissions from the surface of the peatland varied greatly over 24 hours and seasonally. Temperature seemed to be the major environmental factor controlling these variabilities. Concentrations of dissolved VSC's varied with time and space throughout the fen

  20. Alaska's renewable energy potential.

    SciTech Connect

    Not Available

    2009-02-01

    This paper delivers a brief survey of renewable energy technologies applicable to Alaska's climate, latitude, geography, and geology. We first identify Alaska's natural renewable energy resources and which renewable energy technologies would be most productive. e survey the current state of renewable energy technologies and research efforts within the U.S. and, where appropriate, internationally. We also present information on the current state of Alaska's renewable energy assets, incentives, and commercial enterprises. Finally, we escribe places where research efforts at Sandia National Laboratories could assist the state of Alaska with its renewable energy technology investment efforts.

  1. Increases in methylmercury export from a sulfate-amended peatland: A consequence of an altered microbial consortia?

    NASA Astrophysics Data System (ADS)

    Branfireun, B.; Krabbenhoft, D.; Fowle, D.; Jeremiason, J.

    2004-05-01

    An experiment at the Marcell Experimental Forest, Minnesota is ongoing to test the hypothesis that increased atmospheric sulfate deposition to northern peatlands is responsible for increased methylmercury yields from these ecosystems. A peatland, divided into an upslope control portion and a downslope experimental portion, has had elevated levels of sulfate applied to the experimental portion using an extensive irrigation network for several seasons. Increases in methylmercury yield from the system were apparent early in the experimental manipulation. In 2002, peat cores were extracted from the control and experimental areas of the peatland to evaluate whether or not changes in the peat sulfur geochemistry, microbial community structure, and/or mercury methylation potential could be attributed to the sulfate additions. Mercury methylation potential was assessed using a stable isotope addition to incubated intact peat cores, which were subsequently sliced and frozen until analyses. The microbial community structure was assessed using a modified solid-phase extraction followed by phospholipid fatty acid (PLFA) analyses. Although only minor differences in sulfur geochemistry and methylation potential were detected, the treatment cores had increased abundances of Desulfovibrio-group and Desulfobacter-group biomarkers compared to the control cores, and the effect was greatest in the near surface peat. In the control cores, the abundances of sulfate-reducers in both groups increased with depth. These results suggest that increased sulfate loading may cause a shift in microbial community structure and abundance in favour of known mercury methylators.

  2. How hydrology and vegetation modify microclimate of a Sphagnum peatland?

    NASA Astrophysics Data System (ADS)

    Słowińska, Sandra; Słowiński, Michał; Marcisz, Katarzyna; Lamentowicz, Łukasz; Lamentowicz, Mariusz

    2014-05-01

    Climate and hydrology are key factors influencing peat accumulation and decomposition. This, in turn have strong influence on carbon sequestration what is nowadays the central aim of peatlands ecology. However, peatlands are not homogenous ecosystems. There are often a mosaic of vegetation patterns. Differences in depth of groundwater tables are also common at one object. We designed a long-term ecological study site in a Sphagnum peatland in the Northern Poland. We used five meteorological micro-stations and eleven piezometers located along two transects at 5,95 ha area. We have focused on microclimatic and hydrological changes during two growing seasons - 2012 and 2013. Significant differences in radiation, air temperature and humidity were recorded between plots, which were mainly a result of reduction of light availability by trees in two of five plots. That also influenced on surface wetness of Sphagnum mosses. Range of groundwater table changes varied between plots but trends were similar. Further research will focus on the synthesis of relationships between climate, hydrology and vegetation. A separate work will be concentrated on testate amoebae response to wetness, temperature and light availability. Our study is very important to better understand peatland functioning in transition climate in small spatial scale. Project supported by Polish National Science Centre grant No. NN306060940 and the grant PSPB-013/2010 from Switzerland through the Swiss Contribution to the enlarged European Union.

  3. 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.

  4. An Integration of a GIS with Peatland Management

    NASA Technical Reports Server (NTRS)

    Hoshal, J. C.; Johnson, R. L.

    1982-01-01

    The complexities of peatland management in Minnesota and the use of a geographic information system, the Minnesota Land Management Information System (MLMIS) in the management process are examined. General information on the nature of peat and it quantity and distribution in Minnesota is also presented.

  5. Russian boreal peatlands dominate the natural European methane budget

    NASA Astrophysics Data System (ADS)

    Schneider, Julia; Jungkunst, Hermann F.; Wolf, Ulrike; Schreiber, Peter; Gažovič, Michal; Miglovets, Mikhail; Mikhaylov, Oleg; Grunwald, Dennis; Erasmi, Stefan; Wilmking, Martin; Kutzbach, Lars

    2016-01-01

    About 60% of the European wetlands are located in the European part of Russia. Nevertheless, data on methane emissions from wetlands of that area are absent. Here we present results of methane emission measurements for two climatically different years from a boreal peatland complex in European Russia. Winter fluxes were well within the range of what has been reported for the peatlands of other boreal regions before, but summer fluxes greatly exceeded the average range of 5-80 mg CH4 m-2 d-1 for the circumpolar boreal zone. Half of the measured fluxes ranged between 150 and 450 mg CH4 m-2 d-1. Extrapolation of our data to the whole boreal zone of European Russia shows that theses emissions could amount to up to 2.7 ± 1.1 Tg CH4 a-1, corresponding to 69% of the annual emissions from European wetlands or 33% of the total annual natural European methane emission. In 2008, climatic conditions corresponded to the long term mean, whereas the summer of 2011 was warmer and noticeably drier. Counterintuitively, these conditions led to even higher CH4 emissions, with peaks up to two times higher than the values measured in 2008. As Russian peatlands dominate the areal extend of wetlands in Europe and are characterized by very high methane fluxes to the atmosphere, it is evident, that sound European methane budgeting will only be achieved with more insight into Russian peatlands.

  6. Ecological analysis of a boreal peatland CO2 flux based on eddy covariance data set from Ust Pojeg, Russia.

    NASA Astrophysics Data System (ADS)

    Gazovic, Michal; Kutzbach, Lars; Schneider, Julia; Wille, Christian; Wilmking, Martin

    2010-05-01

    Boreal peatlands are an important reservoir of carbon as they store one third of the terrestrial soil organic carbon (C) pool. In the last decades, more and more continuous measurements using eddy covariance technique were conducted in arctic and subarctic regions and these non-intrusive continuous measurements of C fluxes from boreal peatlands proved to be a valuable tool in peatland ecology studies. Results from such non-intrusive experiments were used to address possible changes in peatland functioning. Eddy covariance datasets typically suffer from gaps introduced during technical problems, or when the environmental conditions are not fulfilling the basic theory of eddy covariance. However, enough data points are usually left, to successfully model the missing values. Empirical models, using various environmental variables related to the measured fluxes are a common method. The carbon dioxide (CO2) flux, consistent with the term net ecosystem exchange (NEE), is composed of two reciprocal processes: C assimilation by photosynthesis and ecosystem respiration, consisting of plant and soil respiration. Generally, C accumulation is related to photosynthetically active radiation (PAR) through green leaf area and temperature. Plant respiration is related to temperature changes, and soil respiration additionally to carbon substrate concentrations in the soil solution. With such assumptions, the empirical models are created. However, these models are simple approximations of the world in which the conditions are not stable, but changing over shorter periods, and don't necessarily describe real changes in the environmental controls. Thus, important ecological processes might be "buried" in models integrating over long time periods. Year round measurements of CO2 fluxes from a Russian boreal peatland are presented here, and we test an alternative approach to understand the underlying ecological controls within the annual signal. Moving window regression analysis was used

  7. Impacts of peatland forestation on regional climate conditions in Finland

    NASA Astrophysics Data System (ADS)

    Gao, Yao; Markkanen, Tiina; Backman, Leif; Henttonen, Helena M.; Pietikäinen, Joni-Pekka; Laaksonen, Ari

    2014-05-01

    Climate response to anthropogenic land cover change happens more locally and occurs on a shorter time scale than the global warming due to increased GHGs. Over the second half of last Century, peatlands were vastly drained in Finland to stimulate forest growth for timber production. In this study, we investigate the biophysical effects of peatland forestation on near-surface climate conditions in Finland. For this, the regional climate model REMO, developed in Max Plank Institute (currently in Climate Service Center, Germany), provides an effective way. Two sets of 15-year climate simulations were done by REMO, using the historic (1920s; The 1st Finnish National Forest Inventory) and present-day (2000s; the 10th Finnish National Forest Inventory) land cover maps, respectively. The simulated surface air temperature and precipitation were then analyzed. In the most intensive peatland forestation area in Finland, the differences in monthly averaged daily mean surface air temperature show a warming effect around 0.2 to 0.3 K in February and March and reach to 0.5 K in April, whereas a slight cooling effect, less than 0.2 K, is found from May till October. Consequently, the selected snow clearance dates in model gridboxes over that area are advanced 0.5 to 4 days in the mean of 15 years. The monthly averaged precipitation only shows small differences, less than 10 mm/month, in a varied pattern in Finland from April to September. Furthermore, a more detailed analysis was conducted on the peatland forestation area with a 23% decrease in peatland and a 15% increase in forest types. 11 day running means of simulated temperature and energy balance terms, as well as snow depth were averaged over 15 years. Results show a positive feedback induced by peatland forestation between the surface air temperature and snow depth in snow melting period. This is because the warmer temperature caused by lower surface albedo due to more forest in snow cover period leads to a quicker and

  8. Post-dispersal seed removal by ground-feeding rodents in tropical peatlands, Central Kalimantan, Indonesia.

    PubMed

    Blackham, Grace V; Corlett, Richard T

    2015-01-01

    Forested tropical peatlands in Southeast Asia are being rapidly converted to agriculture or degraded into non-forest vegetation. Although large areas have been abandoned, there is little evidence for subsequent forest recovery. As part of a study of forest degradation and recovery, we used seed removal experiments and rodent surveys to investigate the potential role of post-dispersal seed predation in limiting the regeneration of woody plants. Two 14-day seed removal trials were done in deforested and forested peatland habitat in Central Kalimantan, Indonesia. Seeds of Nephelium lappaceum, Syzygium muelleri, Artocarpus heterophyllus (all animal-dispersed) and Combretocarpus rotundatus (wind-dispersed) were tested. Significantly more seeds (82.8%) were removed in forest than non-forest (38.1%) and Combretocarpus had the lowest removal in both habitats. Most handled seeds were eaten in situ and little caching was observed. Six species of rodents were captured in forest and five in non-forest. The most trapped taxa were three Maxomys spp. in forest (85.5% of individuals) and Rattus tiomanicus in non-forest (74.8%). Camera traps confirmed that rodents were responsible for seed removal. Seed predation in deforested areas, which have a much lower seed rain than forest, may contribute to the low density and diversity of regenerating forest. PMID:26369444

  9. Post-dispersal seed removal by ground-feeding rodents in tropical peatlands, Central Kalimantan, Indonesia

    PubMed Central

    Blackham, Grace V.; Corlett, Richard T.

    2015-01-01

    Forested tropical peatlands in Southeast Asia are being rapidly converted to agriculture or degraded into non-forest vegetation. Although large areas have been abandoned, there is little evidence for subsequent forest recovery. As part of a study of forest degradation and recovery, we used seed removal experiments and rodent surveys to investigate the potential role of post-dispersal seed predation in limiting the regeneration of woody plants. Two 14-day seed removal trials were done in deforested and forested peatland habitat in Central Kalimantan, Indonesia. Seeds of Nephelium lappaceum, Syzygium muelleri, Artocarpus heterophyllus (all animal-dispersed) and Combretocarpus rotundatus (wind-dispersed) were tested. Significantly more seeds (82.8%) were removed in forest than non-forest (38.1%) and Combretocarpus had the lowest removal in both habitats. Most handled seeds were eaten in situ and little caching was observed. Six species of rodents were captured in forest and five in non-forest. The most trapped taxa were three Maxomys spp. in forest (85.5% of individuals) and Rattus tiomanicus in non-forest (74.8%). Camera traps confirmed that rodents were responsible for seed removal. Seed predation in deforested areas, which have a much lower seed rain than forest, may contribute to the low density and diversity of regenerating forest. PMID:26369444

  10. Dynamics of Gross Methane Production and Oxidation in a Peatland Soil

    NASA Astrophysics Data System (ADS)

    McNicol, G.; Yang, W. H.; Teh, Y.; Silver, W. L.

    2012-12-01

    Globally, peatlands are major sources of the potent greenhouse gas methane (CH4) that is implicated in 20% of the post-industrial increase in radiative forcing. Many temperate peatlands have been drained for alternative land-use and are characterized by a layer of unsaturated soil overlying the remnant organic histosol. Drained soil layers may attenuate surface CH4 emissions from deeper, flooded peat layers via microbial CH4 consumption. We measured gross rates of CH4 production and oxidation seasonally across a range of topographic landforms in a partially drained peatland on Sherman Island, California. Net CH4 fluxes across the soil-atmosphere interface ranged from -7.4 to 1096 mg-C m-2 d-1 across all landforms. Fluxes were highest in May and in irrigation ditches (date, p < 0.001; landform, p < 0.001; n = 55). Gross CH4 production rates ranged from 0-1461 mg-C m-2 d-1 and oxidation rates ranged from 0-40 mg-C m-2 d-1. Excluding the irrigation ditches, gross fluxes did not vary seasonally. Gross CH4 fluxes were significantly higher in the hollow/hummock than in the slope. We subsequently selected the hollow/hummock based upon the observation of a strong redox gradient with depth and characterized gross fluxes of CH4 both in the field and in laboratory incubations of four soil depth increments (0-10 cm, 10-30 cm, 30-60 cm, 60-80 cm). The laboratory incubation consisted of 3 separate gross flux experiments: the first using fresh soil under ambient headspace, the second after incubation in an N2 headspace, and the third after incubation in an ambient headspace. Gross CH4 fluxes in the field varied from a slight sink (-0.11 mg-C m-2 d-1) to a large source (23.9 mg-C m-2 d-1). In 3 plots net fluxes were reduced by competing CH4 oxidation. In the depth profile experiment, production and consumption were observed in the fresh soil, but without a clear depth trend. In contrast, we found that consumption rates increased with depth following the aerobic incubation and

  11. Macroinvertebrate community assembly in pools created during peatland restoration.

    PubMed

    Brown, Lee E; Ramchunder, Sorain J; Beadle, Jeannie M; Holden, Joseph

    2016-11-01

    Many degraded ecosystems are subject to restoration attempts, providing new opportunities to unravel the processes of ecological community assembly. Restoration of previously drained northern peatlands, primarily to promote peat and carbon accumulation, has created hundreds of thousands of new open water pools. We assessed the potential benefits of this wetland restoration for aquatic biodiversity, and how communities reassemble, by comparing pool ecosystems in regions of the UK Pennines on intact (never drained) versus restored (blocked drainage-ditches) peatland. We also evaluated the conceptual idea that comparing reference ecosystems in terms of their compositional similarity to null assemblages (and thus the relative importance of stochastic versus deterministic assembly) can guide evaluations of restoration success better than analyses of community composition or diversity. Community composition data highlighted some differences in the macroinvertebrate composition of restored pools compared to undisturbed peatland pools, which could be used to suggest that alternative end-points to restoration were influenced by stochastic processes. However, widely used diversity metrics indicated no differences between undisturbed and restored pools. Novel evaluations of restoration using null models confirmed the similarity of deterministic assembly processes from the national species pool across all pools. Stochastic elements were important drivers of between-pool differences at the regional-scale but the scale of these effects was also similar across most of the pools studied. The amalgamation of assembly theory into ecosystem restoration monitoring allows us to conclude with more certainty that restoration has been successful from an ecological perspective in these systems. Evaluation of these UK findings compared to those from peatlands across Europe and North America further suggests that restoring peatland pools delivers significant benefits for aquatic fauna by

  12. Development of peatlands in northern Minnesota. Final report

    SciTech Connect

    Wright, H.E. Jr.; Glaser, P.H.; Janssens, J.A.

    1985-01-01

    Boreal peatlands are widely distributed across northern Minnesota, where they cover more than 20% of the regional landscape. A regional survey of these peatlands reveals a remarkable degree of uniformity among the vegetation assemblages and an exceptionally close relationship among the vegetation, water chemistry, water level, and presumed hydrology. These relationships are best integrated by the striking landform patterns that, from the air, resemble fluvial landforms such as islands, rivers, and ripple marks. The patterns instead indicate a sensitive adjustment of peat growth to local hydrology and water quality, making the landform patterns an exceptionally important tool for discerning the potential directions and controls on peatland development. A detailed investigation of the Red Lake peatland was undertaken to test a hypothesis on landform development based on an analysis of variations in the present-day landforms, vegetation, water chemistry, and inferred direction of water movement. The peat stratigraphy, based largely on an analysis of fossil bryophytes, indicates that the west-central watershed at Red Lake was overrum by an ombrotrophic bog forest approximately 2000 years ago, but that the forest was subsequently replaced by non-forested Sphagnum communities similar to the vegetation in the present-day bog drains and Sphagnum lawns. These results agree with the initial hypothesis. The stratigraphy indicates that the forested bog islands have expanded over the last 400 years, which indicates a more sensitive adjustment of the patterns to hydrological variations than predicted by the hypothesis. These results may be applicable to a much wider area because of the broad regional uniformity of the peatland patterns. 57 references, 14 figures, 6 tables.

  13. Alaska Library Directory, 1996.

    ERIC Educational Resources Information Center

    Jennings, Mary, Ed.

    This directory of Alaska's Libraries lists: members of the Alaska Library Association (AkLA) Executive Council and Committee Chairs; State Board of Education members; members of the Governor's Advisory Council on Libraries; school, academic and public libraries and their addresses, phone and fax numbers, and contact persons; personal,…

  14. Alaska geothermal bibliography

    SciTech Connect

    Liss, S.A.; Motyka, R.J.; Nye, C.J.

    1987-05-01

    The Alaska geothermal bibliography lists all publications, through 1986, that discuss any facet of geothermal energy in Alaska. In addition, selected publications about geology, geophysics, hydrology, volcanology, etc., which discuss areas where geothermal resources are located are included, though the geothermal resource itself may not be mentioned. The bibliography contains 748 entries.

  15. Renewable Energy in Alaska

    SciTech Connect

    Not Available

    2013-03-01

    This report examines the opportunities, challenges, and costs associated with renewable energy implementation in Alaska and provides strategies that position Alaska's accumulating knowledge in renewable energy development for export to the rapidly growing energy/electric markets of the developing world.

  16. South Central Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Glacial silt along the Copper River in Alaska is picked up by the wind and carried out over the Gulf of Alaska. This true-color MODIS image from October 26, 2001, shows a large gray dust plume spreading out over the Gulf. West of the Copper River Delta, Cook Inlet is full of sediment.

  17. Intermediate-scale vegetation mapping of Innoko National Wildlife Refuge, Alaska using Landsat MSS digital data

    USGS Publications Warehouse

    Talbot, Stephen S.; Markon, Carl J.

    1988-01-01

    A Landsat-derived vegetation map was prepared for lnnoko National Wildlife Refuge. The refuge lies within the northern boreal subzone of northwestern central Alaska. Six major vegetation classes and 21 subclasses were recognized: forest (closed needleleaf, open needleleaf, needleleaf woodland, mixed, and broadleaf); broadleaf scrub (lowland, upland burn regeneration, subalpine); dwarf scrub (prostrate dwarf shrub tundra, erect dwarf shrub heath, dwarf shrub-graminoid peatland, dwarf shrub-graminoid tussock peatland, dwarf shrub raised bog with scattered trees, dwarf shrub-graminoid marsh); herbaceous (graminoid bog, graminoid marsh, graminoid tussock-dwarf shrub peatland); scarcely vegetated areas (scarcely vegetated scree and floodplain); and water (clear, sedimented). The methodology employed a cluster-block technique. Sample areas were described based on a combination of helicopter-ground survey, aerial photo-interpretation, and digital Landsat data. Major steps in the Landsat analysis involved preprocessing (geometric correction), derivation of statistical parameters for spectral classes, spectral class labeling of sample areas, preliminary classification of the entire study area using a maximum-likelihood algorithm, and final classification utilizing ancillary information such as digital elevation data. The final product is 1:250,000-scale vegetation map representative of distinctive regional patterns and suitable for use in comprehensive conservation planning.

  18. The influence of climate on peatland extent in Western Siberia since the Last Glacial Maximum.

    PubMed

    Alexandrov, G A; Brovkin, V A; Kleinen, T

    2016-01-01

    Boreal and subarctic peatlands are an important dynamical component of the earth system. They are sensitive to climate change, and could either continue to serve as a carbon sink or become a carbon source. Climatic thresholds for switching peatlands from sink to source are not well defined, and therefore, incorporating peatlands into Earth system models is a challenging task. Here we introduce a climatic index, warm precipitation excess, to delineate the potential geographic distribution of boreal peatlands for a given climate and landscape morphology. This allows us to explain the present-day distribution of peatlands in Western Siberia, their absence during the Last Glacial Maximum, their expansion during the mid-Holocene, and to form a working hypothesis about the trend to peatland degradation in the southern taiga belt of Western Siberia under an RCP 8.5 scenario for the projected climate in year 2100. PMID:27095029

  19. The influence of climate on peatland extent in Western Siberia since the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Alexandrov, G. A.; Brovkin, V. A.; Kleinen, T.

    2016-04-01

    Boreal and subarctic peatlands are an important dynamical component of the earth system. They are sensitive to climate change, and could either continue to serve as a carbon sink or become a carbon source. Climatic thresholds for switching peatlands from sink to source are not well defined, and therefore, incorporating peatlands into Earth system models is a challenging task. Here we introduce a climatic index, warm precipitation excess, to delineate the potential geographic distribution of boreal peatlands for a given climate and landscape morphology. This allows us to explain the present-day distribution of peatlands in Western Siberia, their absence during the Last Glacial Maximum, their expansion during the mid-Holocene, and to form a working hypothesis about the trend to peatland degradation in the southern taiga belt of Western Siberia under an RCP 8.5 scenario for the projected climate in year 2100.

  20. The influence of climate on peatland extent in Western Siberia since the Last Glacial Maximum

    PubMed Central

    Alexandrov, G. A.; Brovkin, V. A.; Kleinen, T.

    2016-01-01

    Boreal and subarctic peatlands are an important dynamical component of the earth system. They are sensitive to climate change, and could either continue to serve as a carbon sink or become a carbon source. Climatic thresholds for switching peatlands from sink to source are not well defined, and therefore, incorporating peatlands into Earth system models is a challenging task. Here we introduce a climatic index, warm precipitation excess, to delineate the potential geographic distribution of boreal peatlands for a given climate and landscape morphology. This allows us to explain the present-day distribution of peatlands in Western Siberia, their absence during the Last Glacial Maximum, their expansion during the mid-Holocene, and to form a working hypothesis about the trend to peatland degradation in the southern taiga belt of Western Siberia under an RCP 8.5 scenario for the projected climate in year 2100. PMID:27095029

  1. A new model of long-term, coupled dynamics of carbon and water in northern peatlands

    NASA Astrophysics Data System (ADS)

    Frolking, S.; Roulet, N.

    2008-12-01

    We present a new model that simulates coupled carbon and water dynamics of northern peatlands at an annual time step over time scales of decades to millennia. The Holocene Peatland Model (HPM) simulates peatland carbon and water dynamics as the net consequence of several interacting processes: (1) above- and below-ground vegetation NPP and litter production for bryophytes, woody and herbaceous plants; (2) aerobic and anaerobic litter/peat decomposition down the peat profile; (3) the dependence of peat physical and hydraulic properties on peat composition and degree of humification; and (4) peatland annual water balance, water table depth, and unsaturated zone water content. In this initial analysis, a simulation of long- term peat accumulation is compared against peat core data from a northern peatland in North America. The sensitivity of peatland carbon and water dynamics to climate variability are explored.

  2. Extent and status of mires, peatlands, and organic soils in Europe

    NASA Astrophysics Data System (ADS)

    Tanneberger, Franziska; Barthelmes, Alexandra; Tegetmeyer, Cosima; Busse, Stephan; Joosten, Hans

    2016-04-01

    Key words: peatland distribution, peatland drainage, GIS, Global Peatland Database, European Mires Book The relevance of drained peatlands to climate change due to emission of huge amounts of greenhouse gases has recently been recognised e.g. by IPCC, FAO, and the European Union. Oppositely, natural and restored peatlands provide ecosystem services like enhancing biodiversity, nutrient retention, groundwater storage, flood mitigation, and cooling. To evaluate the drainage status of peatlands and organic soils and to develop specific restoration strategies comprehensive and exact geospatial data are needed. The Global Peatland Database (GPD) is hosted at Greifswald Mire Centre (http://tiny.cc/globalpeat). Currently, it provides estimates on location, extent, and drainage status of peatlands and organic soils for 268 countries and regions of the world. Due to the large diversity of definitions and terms for peatlands and organic soils, this mapping follows the broad definition of organic soils from IPCC that gives a minimum soil organic carbon threshold of 12% and considers any depth of the organic layer larger than 10 cm. GIS datasets are continuously collected, specific terms and definitions analysed and the completeness and accuracy of the datasets evaluated. Currently, the GPD contains geospatial data on peatlands and organic soils for all European countries (except Moldova). Recent information on status, distribution, and conservation of mires and peatlands in Europe is summarised in the European Mires Book. It includes descriptions from 49 countries and other geographic entities in Europe. All country chapters follow a generic structure and include also extensive descriptions of national terminology (also in national languages and script) and typologies as well as up to date area statistics and maps. They are complemented by integrative chapters presenting mire classification, mire regionality, peatland use, and mire conservation in Europe. The European Mires

  3. Alaska Problem Resource Manual: Alaska Future Problem Solving Program. Alaska Problem 1985-86.

    ERIC Educational Resources Information Center

    Gorsuch, Marjorie, Ed.

    "Alaska's Image in the Lower 48," is the theme selected by a Blue Ribbon panel of state and national leaders who felt that it was important for students to explore the relationship between Alaska's outside image and the effect of that image on the federal programs/policies that impact Alaska. An overview of Alaska is presented first in this…

  4. Consolidating and updating estimates of northern peatland extents and carbon stocks

    NASA Astrophysics Data System (ADS)

    Hugelius, G.; Loisel, J.; MacDonald, G. M.; Jackson, R. B.; Treat, C. C.; Turetsky, M. R.; Yu, Z.

    2015-12-01

    Conditions favoring peat accumulation have been particularly prevalent in boreal and subarctic regions. The large pool of organic carbon accumulated in Northern peatlands has been an important component in the global carbon cycle throughout the Holocene. All northern peatlands store an estimated 440 Pg organic carbon while a separate study estimates that permafrost region peatlands store ca. 300 Pg organic carbon. However, the degree of overlap between these studies remains unclear and there are differences in methodologies and definitions which prevent direct harmonization of estimates. Here we address this problems by (1) compiling several different databases of field observation data and by (2) comparing previously estimated northern peatland areal extents to the extents of organic soils estimated from compiled harmonized regional and national soil maps from the northern mid and high latitudes. Organic soils are by definition peatlands with >40 cm of near surface peat. The combined estimated extent of organic soils in these maps is 3.44 million km2. This is very similar to the spatial extents of Northern peatlands derived from various national peat resource inventories as reported by previous studies. Our results show that roughly one third of this organic soil area is in permafrost. Based on newly compiled databases we provide spatially distributed estimates of peatland depth and stocks of peat carbon across different biomes. These analyses reveal significant differences in peat depth and carbon stocks between peatland regions and between non-permafrost and permafrost peatlands.

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

    NASA Astrophysics Data System (ADS)

    Euskirchen, E. S.; Edgar, C. W.; Turetsky, M. R.; Waldrop, M. P.; Harden, J. W.

    2014-08-01

    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.

  6. 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.

  7. Alaska marine ice atlas

    SciTech Connect

    LaBelle, J.C.; Wise, J.L.; Voelker, R.P.; Schulze, R.H.; Wohl, G.M.

    1982-01-01

    A comprehensive Atlas of Alaska marine ice is presented. It includes information on pack and landfast sea ice and calving tidewater glacier ice. It also gives information on ice and related environmental conditions collected over several years time and indicates the normal and extreme conditions that might be expected in Alaska coastal waters. Much of the information on ice conditions in Alaska coastal waters has emanated from research activities in outer continental shelf regions under assessment for oil and gas exploration and development potential. (DMC)

  8. Alaska Resource Data File, Wiseman quadrangle, Alaska

    USGS Publications Warehouse

    Britton, Joe M.

    2003-01-01

    Descriptions of the mineral occurrences shown on the accompanying figure follow. See U.S. Geological Survey (1996) for a description of the information content of each field in the records. The data presented here are maintained as part of a statewide database on mines, prospects and mineral occurrences throughout Alaska.

  9. Libraries in Alaska: MedlinePlus

    MedlinePlus

    ... this page: https://medlineplus.gov/libraries/alaska.html Libraries in Alaska To use the sharing features on ... JavaScript. Anchorage University of Alaska Anchorage Alaska Medical Library 3211 Providence Drive Anchorage, AK 99508-8176 907- ...

  10. Hydrology and hydraulics of treatment wetlands constructed on drained peatlands

    NASA Astrophysics Data System (ADS)

    Postila, Heini; Ronkanen, Anna-Kaisa; Kløve, Bjørn

    2013-04-01

    Treatment wetlands are globally used for wastewater purification purposes. In Finland, these wetlands are commonly peatland-based and are used to treat runoff from peat extraction sites and peatland forestry. Wetlands are also used for polishing municipal wastewaters and mining waters. In peat extraction the structures are usually called overland flow areas (OFAs), which are traditionally established on pristine peatlands. However, nowadays establishing of new peat extraction sites is guided to drained peatland areas due to the Finnish Peat Use Strategy, which leads difficulties to find undisturbed peatland area for OFA. Therefore treatment wetlands have had to construct also on drained peatland areas. In drained areas peat physical properties have changed due to oxidation and subsidence and the water flow pathways differs from OFAs flow patterns, which maybe have effect on purification results. Thus in the present study we aim to clarify the hydrology and hydraulic properties of treatment wetlands constructed on drained peatland areas. For this purposes, 20 treatment wetlands on drained peatland areas across Finland were detailed measured for peat hydraulic conductivity. In selected areas, runoff was continuously monitored, flow distribution at treatment areas was studied and water residence times measured with tracer tests using potassium iodide (KI). Generally, in the study areas, the ditches had been completely blocked, partly blocked e.g with peat dams or not blocked at all. The ditches were located partly parallel to the flow direction and partly perpendicular to it. The distribution of water to the wetlands has been implemented in many different ways e.g. by distribution ditch or by perforated pipes. Based on the results, in majority of the wetlands, the peat drainage has clearly affected the hydraulic properties of wetlands, but not on all sites. In more than half of the wetlands (12), the median hydraulic conductivity of peat drastically decreased at the

  11. The effect of source material in determining the photoreactivity of DOM in peatland aquatic systems

    NASA Astrophysics Data System (ADS)

    Pickard, Amy; Heal, Kate; McLeod, Andy; Dinsmore, Kerry

    2016-04-01

    Aquatic systems draining peatlands receive a high loading of dissolved organic matter (DOM) from surrounding terrestrial environments. However the fate of aquatic DOM remains poorly constrained, in part due to lack of knowledge regarding the photoreactivity of DOM and how this changes as a function of variability in source material. In this study water samples were collected monthly for a 13-month period from two contrasting aquatic systems in Scotland: a stream draining a peatland with high DOM concentrations (33.3 ± 14.2 mg DOC L‑1) and a reservoir draining a peat catchment with low DOM concentrations (4.16 ± 0.91 mg DOC L‑1). Controlled UV irradiation laboratory experiments were conducted on samples filtered to 0.2 μm in order to assess the photoreactivity of the DOM, measured as the unit mass of DOC lost upon irradiation. Experiments took place over 8h in temperature controlled conditions, with unirradiated samples used as controls. After exposure, a range of analytical techniques were used to characterise the DOM to yield information about its source material and to determine how this was related to the observed photoreactivity. Lignin phenol analyses indicate considerable contribution of Sphagnum to DOM at the stream site, particularly during summer, as demonstrated by high P-hydroxy/Vanillyl phenol ratios (P/V). Low P/V ratios were correlated with increased photoreactivity, (Pearson's: -0.410; p = 0.15, n = 13), suggesting that DOM from woody lignin sources within the catchment was more photolabile. Photoreactivity was also negatively correlated with Fluorescence Index (FI) values (Pearson's: -0.555; p = 0.055, n = 13), where low FI values are understood to indicate greater contribution of terrestrially derived material to aquatic DOM. Excitation-emission matrices (EEMs) indicate that DOM at the stream site was primarily comprised of a humic-like peak (Ex/Em = 340, 380/460 nm). However, there was also contribution from a protein-like peak (Ex/Em = 290

  12. Pacific Rim Partnerships: Alaska's Bold Initiative.

    ERIC Educational Resources Information Center

    Parrett, William H.; Calkins, Annie

    1989-01-01

    Describes the Alaska Sister Schools Network, formed in 1985 to create opportunities for Alaskan students to experience more directly the cultural and economic perspectives of their Pacific Rim neighbors. Network organizers go beyond the "pen-pal" approach to encourage three partnership levels: initial acquaintance, curriculum development, and…

  13. American Indians and Alaska Natives with Disabilities.

    ERIC Educational Resources Information Center

    Johnson, Marilyn J.

    American Indian and Alaska Native children with special needs experience the same ineffective and inefficient services as other minority language children. This paper discusses the special needs of Native children, assessment and curriculum issues, and recommendations for improvement. It provides statistics for various categories of handicaps and…

  14. How sensitive is the global peatland carbon pool to climate change?

    NASA Astrophysics Data System (ADS)

    Talbot, J.; Frolking, S. E.

    2010-12-01

    Peatlands are important components of boreal and subarctic landscapes, and can be regionally important components of tropical landscapes. As boreal and subarctic peatlands store about one-third of the terrestrial soil carbon pool, peatlands play an important role as a long-term sink for carbon . In the last two decades, many studies have looked at the vulnerability of this carbon pool to the effects of global change (particularly warming and drying), and the potential feedbacks to the atmosphere a change in the peatland carbon pool might bring. The persistent imbalance between the production of decomposition of organic matter in waterlogged conditions results in the accumulation of peat. We synthesized studies looking at the effect of global change (especially warming and drying) on the carbon balance of peatlands. This synthesis shows that the magnitude of the warming or drying required to significantly affect the global peatland carbon pool is higher than the change that is expected over the 21st century, although this conclusion might be different when taking into account the effects of an increase in natural fire frequency or widespread permafrost thaw. We also show that direct anthropogenic impacts on peatlands, especially tropical peatlands, could result in the release of more peatland carbon in the 21st century than warming and/or drying. The simulation of peat accumulation responses to different drying scenarios using the Holocene Peatland Model also indicates that a very sharp and sustained decline in water table depth is required to significantly affect the carbon pool of a mature peatland, and that this response differs depending on how the vegetation is allowed to change in the course of the simulations.

  15. Land-use Changes on Peatlands in Russia and Green House Gas Emissions

    NASA Astrophysics Data System (ADS)

    Sirin, A.; Minaeva, T.; Chistotin, M.; Glagolev, M.; Suvorov, G.

    2009-04-01

    Russia possesses vast areas of peatlands and associated paludified shallow peat lands, over 8 and 20% respectively. The country is the largest World peatland nation, and thus could be responsible for the large part of GHG exchange between peatlands and the atmosphere. Russian peatlands present a high variety of natural conditions from permafrost mires to bogs, fens and swamps within boreal, temperate, steppe and semi-arid zones, which have quite different rates of GHG flux, emitting or absorbing carbon dioxide and methane. Many regions of Russia still contain vast areas of virgin mires but in the central European part of Russia, West Siberia and Far East the appreciable part of peatlands was already modified. Peatlands were used in a broad spectrum of human activities connected with direct water level draw-down: peat extraction for different purposes (up to 1.5 million ha), drainage for agriculture, and drainage for forestry (each over 3 million ha). Many peatlands all the over the country were affected by infrastructure development (by road, pipe line construction etc.) with related changes of their hydrology and GHG fluxes. These land uses are under consideration of LULUFC issues of UNFCCC, and peat excavation is directly included in IPCC 2006 Guidelines as a main wetland/peatland land use activity related to climate change mitigation. General estimates and geographical distribution of peatlands drained for agriculture and forestry as well as peatlands under excavation, extracted or abandoned are given based on existing statistical and sectoral information. GHG fluxes from disturbed peatlands are analyzed using available Russian data and the results of specially organized observations in 2004-2008 in the pilot regions in Central European Russia and West Siberia which included a variety of modified and virgin control sites.

  16. Climate Change Driven Implications on Spatial Distribution of High Andean Peatlands in the Central Andes

    NASA Astrophysics Data System (ADS)

    Otto, Marco; Gibbons, Richard E.

    2013-04-01

    High Andean peatlands are among the most unique habitats in the tropical Andes and certainly among the least studied. High Andean peatlands occur patchily in montane grassland and scrub below snow line and above tree line. These high-elevation peatlands are sustained by glacial runoff and seasonal precipitation. We used remote sensing data to estimate that peatland habitat is approximately 2.5 % of our study region in the Puna, an ecoregion located in the high Andes above 4000 m a.s.l. Individual sizes of our estimated peatland polygons ranged from 0.72 ha to 1079 ha with a mean size of 4.9 ha. Climate change driven implications on spatial distribution of high Andean peatlands were assessed in two ways. First, we estimated the effect of predicted regional temperature increase by using the standard lapse rate of 2° C per 300 m for assessing peatland habitat patches that would remain above a critical thermocline. Nearly 80% of peatland habitat patches were predicted to occur below the thermocline if the prediction of 4° C temperature increase is realized. The second assessment relied on the quantified assumption that permanent snow or glacier cover, topographic characteristics (e.g. slope) and precipitation of a basin are essential variables in the occurrence of high Andean peatlands. All 17 basins were predicted to have a decrease in peatland habitat due to snow line uplift, decrease in precipitation and consequent insufficient wetland inflows. Total habitat loss was predicted for two basins in the semi-arid part of the study area with a snow line uplift to 5600 m and a projected decrease in precipitation of 1 mm per year over the next 40 years. A combined result of both assessments provides important information on climate change driven implications on the hydrology of high Andean peatlands and potential consequences for their spatial distribution within the Central Andes.

  17. WikiPEATia - a web based platform for assembling peatland data through ‘crowd sourcing’

    NASA Astrophysics Data System (ADS)

    Wisser, D.; Glidden, S.; Fieseher, C.; Treat, C. C.; Routhier, M.; Frolking, S. E.

    2009-12-01

    The Earth System Science community is realizing that peatlands are an important and unique terrestrial ecosystem that has not yet been well-integrated into large-scale earth system analyses. A major hurdle is the lack of accessible, geospatial data of peatland distribution, coupled with data on peatland properties (e.g., vegetation composition, peat depth, basal dates, soil chemistry, peatland class) at the global scale. This data, however, is available at the local scale. Although a comprehensive global database on peatlands probably lags similar data on more economically important ecosystems such as forests, grasslands, croplands, a large amount of field data have been collected over the past several decades. A few efforts have been made to map peatlands at large scales but existing data have not been assembled into a single geospatial database that is publicly accessible or do not depict data with a level of detail that is needed in the Earth System Science Community. A global peatland database would contribute to advances in a number of research fields such as hydrology, vegetation and ecosystem modeling, permafrost modeling, and earth system modeling. We present a Web 2.0 approach that uses state-of-the-art webserver and innovative online mapping technologies and is designed to create such a global database through ‘crowd-sourcing’. Primary functions of the online system include form-driven textual user input of peatland research metadata, spatial data input of peatland areas via a mapping interface, database editing and querying editing capabilities, as well as advanced visualization and data analysis tools. WikiPEATia provides an integrated information technology platform for assembling, integrating, and posting peatland-related geospatial datasets facilitates and encourages research community involvement. A successful effort will make existing peatland data much more useful to the research community, and will help to identify significant data gaps.

  18. Water budget of a Quebec North-boreal minerotrophic peatland

    NASA Astrophysics Data System (ADS)

    Jutras, S.; Rousseau, A. N.; St-Hilaire, A.; Carrer, G.; Proulx-McInnis, S.; Clerc, C.; Levrel, G.

    2009-05-01

    A significant percentage of the northern Quebec boreal region consists of minerotrophic peatland. Their impact on large-scale watersheds, used for hydroelectric production, is important, especially in relation to climate change. During the last decades, a subtle increase in the surface of ponds at the expense of terrestrial compartments has been observed. To better understand the impacts of this development, a multidisciplinary study to perform a complete integrated analysis of the water balance was launched in summer 2008 on the Abeille peatland (54° 06'52" N, 72° 30'01"W), a minerotrophic peatland with an open-water surface. While all features of the water balance will be considered (precipitation, evapotranspiration, runoff, storage and error), some will be studied in greater depth. Notably, evapotranspiration and storage changes will be considered, since, they are particularly difficult to measure in peatland ecosystems. Indirect methods for estimating actual evapotranspiration are often used. One method is to use a semi-empirical formula to estimate potential evapotranspiration. The main problem with this method is that a relationship between potential and actual evapotranspiration must be established and this is a highly variable process for peat ecosystems. To establish a relationship appropriate to our study site, different methods of direct measurement of the actual evapotranspiration will be used (lysimeters, turbulence flow, daily fluctuations of storage, etc.) and compared. A dense network of wells has been installed to enable monitoring of changes in storage and subsurface runoff. A high accuracy topographic survey will be executed to assess the total water content of the site. A device for measuring the variation of peat surface elevation will also be established. Preliminary results are showing complex dynamic behaviors of water migration through the site, therefore opening the way to new questions and hypotheses to clarify in the coming years.

  19. Vegetation management with fire modifies peatland soil thermal regime.

    PubMed

    Brown, Lee E; Palmer, Sheila M; Johnston, Kerrylyn; Holden, Joseph

    2015-05-01

    Vegetation removal with fire can alter the thermal regime of the land surface, leading to significant changes in biogeochemistry (e.g. carbon cycling) and soil hydrology. In the UK, large expanses of carbon-rich upland environments are managed to encourage increased abundance of red grouse (Lagopus lagopus scotica) by rotational burning of shrub vegetation. To date, though, there has not been any consideration of whether prescribed vegetation burning on peatlands modifies the thermal regime of the soil mass in the years after fire. In this study thermal regime was monitored across 12 burned peatland soil plots over an 18-month period, with the aim of (i) quantifying thermal dynamics between burned plots of different ages (from <2 to 15 + years post burning), and (ii) developing statistical models to determine the magnitude of thermal change caused by vegetation management. Compared to plots burned 15 + years previously, plots recently burned (<2-4 years) showed higher mean, maximum and range of soil temperatures, and lower minima. Statistical models (generalised least square regression) were developed to predict daily mean and maximum soil temperature in plots burned 15 + years prior to the study. These models were then applied to predict temperatures of plots burned 2, 4 and 7 years previously, with significant deviations from predicted temperatures illustrating the magnitude of burn management effects. Temperatures measured in soil plots burned <2 years previously showed significant statistical disturbances from model predictions, reaching +6.2 °C for daily mean temperatures and +19.6 °C for daily maxima. Soil temperatures in plots burnt 7 years previously were most similar to plots burned 15 + years ago indicating the potential for soil temperatures to recover as vegetation regrows. Our findings that prescribed peatland vegetation burning alters soil thermal regime should provide an impetus for further research to understand the consequences of thermal regime

  20. 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.

  1. Alaska: A frontier divided

    SciTech Connect

    O'Dell, R. )

    1986-09-01

    The superlatives surrounding Alaska are legion. Within the borders of the 49th US state are some of the world's greatest concentrations of waterfowl, bald eagles, fur seals, walrus, sea lions, otters, and the famous Kodiak brown bear. Alaska features the highest peak of North America, the 20,320-foot Mount McKinley, and the longest archipelago of small islands, the Aleutians. The state holds the greatest percentage of protected wilderness per capita in the world. The expanse of some Alaskan glaciers dwarfs entire countries. Like the periodic advance and retreat of its glaciers, Alaska appears with some regularity on the national US agenda. It last achieved prominence when President Jimmy Carter signed the Alaska National Interest Lands Conservation Act in 1980. Since then the conflict between environmental protection and economic development has been played out throughout the state, and Congress is expected to turn to Alaskan issues again in its next sessions.

  2. Variations in dissolved organic carbon concentrations across peatland hillslopes

    NASA Astrophysics Data System (ADS)

    Boothroyd, I. M.; Worrall, F.; Allott, T. E. H.

    2015-11-01

    Peatlands are important terrestrial carbon stores and dissolved organic carbon (DOC) is one of the most important contributors to carbon budgets in peatland systems. Many studies have investigated factors affecting DOC concentration in peatland systems, yet hillslope position has been thus far overlooked as a variable that could influence DOC cycling. This study investigates the importance of hillslope position with regard to DOC cycling. Two upland peat hillslopes were studied in the Peak District, UK, to determine what impact, if any, hillslope position had upon DOC concentration. Hillslope position was found to be a significant factor affecting variation in soil pore water DOC concentration, with bottom-slope positions having significantly lower DOC concentrations than up-slope because of dilution of DOC as water moves down-slope and is flushed out of the system via lateral throughflow. Water table drawdown on steeper mid-slopes increased DOC concentrations through increased DOC production and extended residence times allowing a build-up of humic-rich DOC compounds. Hillslope position did not significantly affect DOC concentrations in surface runoff water because of the dilution of near-surface soil pore water by precipitation inputs, while stream water had similar water chemistry properties to soil pore water under low-flow conditions.

  3. Redox reactions of dissolved organic matter contribute to anaerobic sulphur cycling in peatland soils

    NASA Astrophysics Data System (ADS)

    Blodau, C.; Margit, R.; Bernhard, M.; Moore, T. R.

    2004-05-01

    Sulphate reduction rates in wetland soils typically account for a large fraction of the anaerobic electron flow, despite small pool sizes of sulphate in the pore waters. The studies objective was to test the hypothesis that recycling of sulphur occurs and that redox-reactions of dissolved organic matter (DOM) are involved in the recycling process. To examine the recycling process we used peat mesocosm from two peatlands in Ontario, Canada and subjected them to sulphur deposition and vertical water flow of about 2 mm/day. Depth profiles of DOC and sulphate concentrations were determined and vertical mass balances calculated. In addition we determined 34S sulphate profiles of pore waters. Batch experiments with addition of H2S to solutions of standard peat humic acid (Pahokee Peat, IHSS) were used to determine whether H2S was oxidized by humic acids, and what the reaction products were. Enrichment with 34S at intermediate depths, constant sulphate concentrations with depth and absence of oxygen suggested that sulphate reduction and anaerobic sulphate release concurrently occurred. In the batch experiments two apparent reactions of H2S with DOM were observed. In the fast initial reaction, H2S was oxidized mostly to elemental sulphur and secondarily to sulphate. Production of thiosulfate was not observed. In a slower reaction step H2S was further consumed and the sum of dissolved inorganic forms of sulphur in the pore water decreased. This was interpreted as H2S being incorporated into the organic substance. No systematic relationship between pH and the oxidation process was found. Overall the results suggest that dissolved organic matter is involved in an anaerobic sulphur cycle allowing for high rates of sulphate reduction in sulphate-poor peatlands.

  4. Improving Indonesian peatland C stock estimates using ground penetrating radar (GPR) and electrical resistivity imaging (ERI)

    NASA Astrophysics Data System (ADS)

    Terry, N.; Comas, X.; Slater, L. D.; Warren, M.; Kolka, R. K.; Kristijono, A.; Sudiana, N.; Nurjaman, D.; Darusman, T.

    2014-12-01

    Tropical peatlands sequester an estimated 15% of the carbon pool from peatlands worldwide. Indonesian peatlands account for approximately 65% of all tropical peat, and are believed to be the largest global source of carbon dioxide emissions to the atmosphere from degrading peat. However, there is great uncertainty in these estimates due to insufficient data regarding the thickness of organic peat soils and their carbon content. Meanwhile, Indonesian peatlands are threatened by heightening pressure to drain and develop. Indirect geophysical methods have garnered interest for their potential to non-invasively estimate peat depth and gas content in boreal peatlands. Drawing from these techniques, we employed ground penetrating radar (GPR) and electrical resistivity imaging (ERI) in tandem with direct methods (core sampling) to evaluate the potential of these methods for tropical peatland mapping at 2 distinct study sites on West Kalimantan (Indonesia). We find that: [1] West Kalimantan peatland thicknesses estimated from GPR and ERI in intermediate/shallow peat can vary substantially over short distances (for example, > 2% over less than 0.02° surface topography gradient), [2] despite having less vertical resolution, ERI is able to better resolve peatland thickness in deep peat, and [3] GPR provides useful data regarding peat matrix attributes (such as the presence of wood layers). These results indicate GPR and ERI could help reduce uncertainty in carbon stocks and aid in responsible land management decisions in Indonesia.

  5. Initial response of the nitrogen cycle to soil warming in Northern Minnesota peatlands

    EPA Science Inventory

    Peatlands store 30% of global soil carbon. Many of these peatlands are located in boreal regions which are expected to have the highest temperature increases in response to climate change. As climate warms, peat decomposition may accelerate and release greenhouse gases. Spruce a...

  6. Do peatlands or lakes provide the most comprehensive distal tephra records?

    NASA Astrophysics Data System (ADS)

    Watson, E. J.; Swindles, G. T.; Lawson, I. T.; Savov, I. P.

    2016-05-01

    Despite the widespread application of tephra studies for dating and correlation of stratigraphic sequences ('tephrochronology'), questions remain over the reliability and replicability of tephra records from lake sediments and peats, particularly in sites >1000 km from source volcanoes. To address this, we examine the tephrostratigraphy of four pairs of lake and peatland sites in close proximity to one another (<10 km), and evaluate the extent to which the microscopic (crypto-) tephra records in lakes and peatlands differ. The peatlands typically record more cryptotephra layers than nearby lakes, but cryptotephra records from high-latitude peatlands can be incomplete, possibly due to tephra fallout onto snow and subsequent redistribution across the peatland surface by wind and during snowmelt. We find no evidence for chemical alteration of glass shards in peatland or lake environments over the time scale of this study (mid-to late- Holocene). Instead, the low number of basaltic cryptotephra layers identified in distal peatlands reflects the capture of only primary tephra-fall, whereas lakes concentrate tephra falling across their catchments which subsequently washes into the lake, adding to the primary tephra fallout received in the lake. A combination of records from both lakes and peatlands must be used to establish the most comprehensive and complete regional tephrostratigraphies. We also describe two previously unreported late Holocene cryptotephras and demonstrate, for the first time, that Holocene Icelandic ash clouds frequently reached Arctic Sweden.

  7. MANAGEMENT OF PEATLAND SHRUB- AND FOREST-DOMINATED COMMUNITIES FOR THREATENED AND ENDANGERED SPECIES

    EPA Science Inventory

    Plant communities found on peatland soils include forests, basin shrublands, and seepage communities. The ecology and management of six communities are reviewed, with an emphasis on land uses associated with Department of Defense (DoD) installations. Peatland plant communities in...

  8. Alaska Resource Data File, Point Lay quadrangle, Alaska

    USGS Publications Warehouse

    Grybeck, Donald J.

    2006-01-01

    This report gives descriptions of the mineral occurrences in the Point Lay 1:250,000-scale quadrangle, Alaska. The data presented here are maintained as part of a statewide database on mines, prospects and mineral occurrences throughout Alaska.

  9. Do volcanic emissions affect carbon gas fluxes in peatlands?

    NASA Astrophysics Data System (ADS)

    Harrison, Nicola; Delmelle, Pierre; Toet, Sylvia; Gauci, Vincent; Ineson, Phil

    2010-05-01

    Recently, a link has been suggested between volcanic deposition of SO4 and the suppression of CH4 emissions in northern peatlands (Gauci et al., 2008). This link stems from the widely accepted idea that acid rain SO4 additions to peatlands can cause a shift in microbial communities as SO4 reducing bacteria out-compete methanogens for substrates, which results in a suppression of CH4 emission. However, volcanic emissions contain besides S other chemically reactive species that are potentially harmful to the environment. In particular, gaseous and particulate F emissions from volcanoes constitute a steady or intermittent source of F emission and deposition into the environment both close to the source and within fallout range of large eruptions. The objective of this study was to investigate the effect of volcanic depositions of SO4, both alone and in combination with F, on CH4 emission in peatlands. Peat mesocosms collected from Pennine uplands in the UK were treated with weekly pulses of Na2SO4 and NaF over 20 weeks in doses of 74 kg SO4/ ha and 13.5 and 135 kg F /ha. CH4 emissions were measured at regular intervals by taking headspace samples, which were analysed by GC-FID. CO2 fluxes were also measured using a portable Infra Red Gas Analyser (IRGA). No significant differences in CH4 and CO2 emissions were observed for any of the treatments when compared to the controls, which had only received deionised water. These findings are in contrast with previous studies where SO4 reduces CH4 emission in peatlands. The reason for this is unclear but may be due to the heterogeneous nature of peat soils. An alternative explanation relates to the previous history of the soils used in the mesocosms which are known to have been previously exposed to large volumes of anthropogenic S pollution. This may have caused microbial communities to evolve and become acclimatised to high levels of S addition. In either case, the assumption that CH4 suppression in peatlands occurs upon

  10. Incorporating Peatland Plant Communities into the Enzymic 'Latch' Hypothesis: Can Vegetation Influence Carbon Storage Mechanisms?

    NASA Astrophysics Data System (ADS)

    Romanowicz, K. J.; Daniels, A. L.; Potvin, L. R.; Kane, E. S.; Kolka, R. K.; Chimner, R. A.; Lilleskov, E. A.

    2012-12-01

    cores are being assayed monthly from June - October for two oxidase enzyme activities (phenol oxidase, peroxidase) and four hydrolase enzyme activities (β-glucosidase, chitinase, cellobiohydrolase, and acid-phosphatase). Early season assays (June and July) where water table treatments did not significantly vary showed trends of decreasing oxidase activities while hydrolase activities increased. These preliminary results show no significant differences between vegetation treatments but as the season progresses (August - October), water table levels between high and low treatments will continue to experience greater dissimilarities. These water table declines within sedge and ericaceous shrub communities may have opposing effects on rhizosphere extracellular enzyme activities indicating plant communities may significantly influence belowground carbon storage mechanisms in ways not previously considered in peatland ecosystems.

  11. Ecological restoration of peatlands in steppe and forest-steppe areas

    NASA Astrophysics Data System (ADS)

    Minayeva, Tatiana; Sirin, Andrey; Dugarjav, Chultem

    2016-04-01

    Peatlands in the arid and semi-arid regions of steppe and forest steppe belt of Eurasia have some specific features. That demands the special approach to their management and restoration. The distribution of peatlands under conditions of dry climate is very limited and they are extremely vulnerable. Peatlands in those regions are found in the highlands where temperate conditions still present, in floodplains where they can get water from floods and springs, or in karst areas. Peatlands on watersheds present mainly remains from the more humid climate periods. Water and carbon storage as well as maintenance of the specific biodiversity are the key ecosystem natural functions of peatlands in the steppe and forest steppe. The performance of those functions has strong implications for people wellness and livelihood. Anyhow, peatlands are usually overlooked and poorly represented in the systems of natural protected areas. Land management plans, mitigation and restoration measures for ecosystems under use do not usually include special measures for peatlands. Peatlands'use depends on the traditional practices. Peat extraction is rather limited in subhumid regions but still act as one of the threats to peatlands. The most of peatlands are used as pastures and grasslands. In densely populated areas large part of peatlands are transformed to the arable lands. In many cases peatlands of piedmonts and highlands are affected by industrial developments: road construction, mining of subsoil resources (gold, etc.). Until now, the most of peatlands of steppe and forest steppe region are irreversibly lost, what also effects water regime, lands productivity, biodiversity status. To prevent further dramatic changes the ecological restoration approach should be introduced in the subhumid regions. The feasibility study to assess the potential for introducing ecological restoration techniques for peatlands in the arid and semi-arid conditions had been undertaken in steppe and forest

  12. Hydromorphological analysis and water balance modelling of ombro- and mesotrophic peatlands

    NASA Astrophysics Data System (ADS)

    Edom, F.; Münch, A.; Dittrich, I.; Keßler, K.; Peters, R.

    2010-10-01

    The hydromorphological analysis (HMA) is a method to quantify the potentials of mire revitalisation. In this study, the HMA is combined with the new peatland-tool of the water balance model AKWA-M®. This peatland-tool includes as well depth functions of the hydraulic conductivity and drainable porosity for several mire-ecotope-types as specific equations for mire evapotranspiration. The calculations were applied in several peatlands and mires of the German-Czech Ore Mountains (Erzgebirge/Krušné hory). The simulation results show that the chosen depth functions are valuable for the water balance calculation of mire ecotopes with a fully developed akrotelm like ombro- and mesotrophic peatlands. For degenerated peat soil or regenerating mires it is necessary to improve the model and the parameter calibration, especially the depth functions, with additional measured data in different peatlands.

  13. Simulating long-term carbon and water dynamics in northern peatlands (Invited)

    NASA Astrophysics Data System (ADS)

    Frolking, S. E.; Roulet, N. T.; Quillet, A.; Tuittila, E.; Bubier, J. L.

    2009-12-01

    We present a new model that simulates coupled carbon and water dynamics of northern peatlands at an annual time step over time scales of decades to millennia. The Holocene Peatland Model (HPM) simulates peatland carbon and water dynamics as the net consequence of several interacting processes: (1) above- and below-ground vegetation NPP and litter production for bryophytes and vascular plants; (2) aerobic and anaerobic litter/peat decomposition down the peat profile; (3) the dependence of peat physical and hydraulic properties on peat humification; and (4) peatland annual water balance, water table depth, and unsaturated zone water content. The model generates time series of vegetation, carbon and water dynamics over a 5000-10000 year simulation, and a ‘final state’ peat core that can be compared to contemporary peat core data. The sensitivities of peatland carbon and water dynamics to climate and climate variability and to succession rate are evaluated.

  14. Alaska Resource Data File: Chignik quadrangle, Alaska

    USGS Publications Warehouse

    Pilcher, Steven H.

    2000-01-01

    Descriptions of the mineral occurrences can be found in the report. See U.S. Geological Survey (1996) for a description of the information content of each field in the records. The data presented here are maintained as part of a statewide database on mines, prospects and mineral occurrences throughout Alaska. There is a website from which you can obtain the data for this report in text and Filemaker Pro formats

  15. Ecohydrology by thinking outside the bog: Shifting paradigms in an era of shifting peatland ecosystems

    NASA Astrophysics Data System (ADS)

    Waddington, James; Moore, Paul

    2016-04-01

    Large shifts in vegetation distributions are occurring worldwide and at unprecedented rates. The most extreme of these regime shifts are expected to occur at ecosystem boundaries of both semi-arid and semi-humid landscapes. Despite extensive hydrological research on the interactions between water and semi-arid ecosystems, research in peatlands on the wet end of ecosystem continuum has been "bogged down" (pun fully intended) by the traditional conceptual models (paradigms?) of peatland hydrology and ecology. The consequences of this "thinking" are large given that northern peatlands provide important global and regional ecosystem services (carbon storage, water storage, and biodiversity). This is especially true because peatlands face increases in the severity, areal extent, and frequency of climate-mediated (e.g., wildfire, drought) and land-use change (e.g., drainage, flooding, and mining) disturbances placing the future security of these critical ecosystem services in doubt. We use the word doubt because while numerical modelling studies predict peatland regime shifts and the demise of global peat stocks, there is growing evidence that peatlands are self-regulating ecosystems dominated by negative ecohydrological feedbacks that stabilize the aforementioned ecosystem services through high ecosystem resilience to disturbance. This raises several important hydrological questions? "Is there field evidence of peatland regime shifts? If so, what are the potential impacts of these shifts on water resources and watershed management? If not, are researchers actually looking in the right places (or times)? In this presentation we explore the need for a "thinking outside the bog" in order to understand the ecohydrological consequences of transformative landscape change caused by peatland regime shifts. With reference to over two decades of field research, recent advances with our Peatland Hydrological Impacts model and recent research examining primary peat formation, we

  16. Nitrogen fixation in boreal peatlands: the effects of increased N deposition on N2-fixation

    NASA Astrophysics Data System (ADS)

    Popma, J. M.; Wieder, R.; Lamers, L.; Vile, M. A.

    2013-12-01

    Boreal peatlands are of great importance to global carbon and nitrogen cycling. While covering only 3-4 % of the terrestrial surface, they account for 25-30 % of the world's soil C and 9-15 % of the world's soil N. In Western Canada atmospheric dry deposition rates are extremely low: approximately 1 kg N ha-1 yr-1. Though these systems have been functioning as net sinks over the past 11,000 years, natural and anthropogenic disturbances might compromise the historical balance of C and N. Biological N2-fixation has recently been shown to represent a very significant input of N into these systems, contributing to 62% of total N in Western Canada. Interactions between N deposition and biological N2-fixation are as yet, unknown, but the impact of elevated deposition of N-compounds from increased industrial expansion of oil sands mining to peatlands, is concerning. Given that nitrogenase, the enzyme responsible for catalyzing N2-fixation, is energetically costly when active, enhanced inputs of atmospheric N deposition could be a major determinant for enzyme activity and rates of biological N input to these bogs. Understanding interactions between N deposition and N2 fixation in boreal peatlands can aid in predicting the consequences of increased N deposition and setting critical loads. We conducted a field-fertilization experiment in a poor fen in Alberta, Canada, to determine the effects of enhanced N deposition on a dominant fen species Sphagnum angustifolium. The experiment consisted of seven N treatments: Control, 0, 5, 10, 15, 20 and 25 kg N ha-1 y1, n=3. N2-fixation was measured during summer 2012 and 2013 using the acetylene reduction assay (ARA). ARA rates were converted to rates of N2-fixation by calibrating ARA with paired 15N2-incubations. In both 2012 and 2013, with increasing N deposition from 0 kg N ha-1 yr-1 to 25 kg N ha-1 yr-1, rates of N2 fixation decreased, with highest rates in the 0 kg N ha-1 yr-1 treatment mosses (54.2 × 1.40; 48.58 × 7.12 kg N ha

  17. Production of Excess CO2 relative to methane in peatlands: a new H2 sink

    NASA Astrophysics Data System (ADS)

    Wilson, R.; Woodcroft, B. J.; Varner, R. K.; Tyson, G. W.; Tfaily, M. M.; Sebestyen, S.; Saleska, S. R.; Rogers, K.; Rich, V. I.; McFarlane, K. J.; Kostka, J. E.; Kolka, R. K.; Keller, J.; Iversen, C. M.; Hodgkins, S. B.; Hanson, P. J.; Guilderson, T. P.; Griffiths, N.; de La Cruz, F.; Crill, P. M.; Chanton, J.; Bridgham, S. D.; Barlaz, M.

    2015-12-01

    Methane is generated as the end product of anaerobic organic matter degradation following a series of reaction pathways including fermentation and syntrophy. Along with acetate and CO2, syntrophic reactions generate H2 and are only thermodynamically feasible when coupled to an exothermic reaction that consumes H2. The usual model of organic matter degradation in peatlands has assumed that methanogenesis is that exothermic H2-consuming reaction. If correct, this paradigm should ultimately result in equimolar production of CO2 and methane from the degradation of the model organic compound cellulose: i.e. C6H12O6 à 3CO2 + 3CH4. However, dissolved gas measurement and modeling results from field and incubation experiments spanning peatlands across the northern hemisphere have failed to demonstrate equimolar production of CO2 and methane. Instead, in a flagrant violation of thermodynamics, these studies show a large bias favoring CO2 production over methane generation. In this talk, we will use an array of complementary analytical techniques including FT-IR, cellulose and lignin measurements, 13C-NMR, fluorescence spectroscopy, and ultra-high resolution mass spectrometry to describe organic matter degradation within a peat column and identify the important degradation mechanisms. Hydrogenation was the most common transformation observed in the ultra-high resolution mass spectrometry data. From these results we propose a new mechanism for consuming H2 generated during CO2 production, without concomitant methane formation, consistent with observed high CO2/CH4 ratios. While homoacetogenesis is a known sink for H2 in these systems, this process also consumes CO2 and therefore does not explain the excess CO2 measured in field and incubation samples. Not only does the newly proposed mechanism consume H2 without generating methane, but it also yields enough energy to balance the coupled syntrophic reactions, thereby restoring thermodynamic order. Schematic of organic matter

  18. Environmental drivers of carbon and nitrogen isotopic signatures in peatland vascular plants along an altitude gradient.

    PubMed

    Gavazov, Konstantin; Hagedorn, Frank; Buttler, Alexandre; Siegwolf, Rolf; Bragazza, Luca

    2016-01-01

    Peatlands are important sinks of atmospheric carbon (C) that, in response to climate warming, are undergoing dynamic vegetation succession. Here we examined the hypothesis that the uptake of nutrients by different plant growth forms (PGFs) is one key mechanism driving changes in species abundance in peatlands. Along an altitude gradient representing a natural climate experiment, we compared the variability of the stable C isotope composition (δ(13)C) and stable nitrogen (N) isotope composition (δ(15)N) in current-year leaves of two major PGFs, i.e. ericoids and graminoids. The climate gradient was associated with a gradient of vascular plant cover, which was parallelled by different concentrations of organic and inorganic N as well as the fungal/bacterial ratio in peat. In both PGFs the (13)C natural abundance showed a marginal spatial decrease with altitude and a temporal decrease with progression of the growing season. Our data highlight a primary physical control of foliar δ(13)C signature, which is independent from the PGFs. Natural abundance of foliar (15)N did not show any seasonal pattern and only in the ericoids showed depletion at lower elevation. This decreasing δ(15)N pattern was primarily controlled by the higher relative availability of organic versus inorganic N and, only for the ericoids, by an increased proportion of fungi to bacteria in soil. Our space-for-time approach demonstrates that a change in abundance of PGFs is associated with a different strategy of nutrient acquisition (i.e. transfer via mycorrhizal symbiosis versus direct fine-root uptake), which could likely promote observed and predicted dwarf shrub expansion under climate change. PMID:26433961

  19. Effects of inorganic sulfur addition on fluxes of volatile sulfur compounds in Sphagnum peatlands

    NASA Technical Reports Server (NTRS)

    Demello, William Zamboni; Hines, Mark E.; Bayley, Suzanne E.

    1992-01-01

    Short and long-term impacts of increased S deposition on fluxes of volatile S compounds (VSC's) from Sphagnum peatlands were investigated in an artificially acidified (sulfuric and nitric acids) poor fen (Mire 239) at the Experimental Lakes Area (ELA), Ontario, Canada. Additional experiments were conducted in a poor fen (Sallie's Fen) in Barrington, NH, USA. At Mire 239, emissions of VSC's were monitored, before and after acidification, at control (unacidified) and experimental sections within two major physiographic zones of the mire (oligotrophic and minerotrophic). The experimental segments of the mire received S amendments since 1983, in amounts equivalent to the annual S deposition in the highest polluted areas of Canada and U.S. Dimethyl sulfide (DMS) was the predominant VSC released from the mire and varied largely with time and space (i.e., from 2.5 to 127 nmol/m(sup -2)h(sup -1)). Sulfur addition did not affect DMS emissions in a period of hours to a few days, although it stimulated production of DMS and MSH in the anoxic surficial regions of the peat. DMS emissions in the experimental oligotrophic segment of the mire was approximately 3-fold greater than in the control oligotrophic segment, and approximately 10-fold greater than in the minerotrophic zones. These differences could be due to a combination of differences in types of vegetation, nutritional status, and S input. At Sallie's Fen, DMS fluxes were approximately 8 times higher from a Sphagnum site than from a bare peat site. Fluxes of VSC's were not significantly affected by sulfate amendments at both sites, while DMS and MSH concentrations increases greatly with time in the top 10 cm of the peat column. Our data indicated that although Sphagnum is not the direct source of DMS released from Sphagnum peatlands, it might play a role in regulating DMS emissions to the atmosphere.

  20. Flood frequency in Alaska

    USGS Publications Warehouse

    Childers, J.M.

    1970-01-01

    Records of peak discharge at 183 sites were used to study flood frequency in Alaska. The vast size of Alaska, its great ranges of physiography, and the lack of data for much of the State precluded a comprehensive analysis of all flood determinants. Peak stream discharges, where gaging-station records were available, were analyzed for 2-year, 5-year, 10-year, 25-year, and 50-year average-recurrence intervals. A regional analysis of the flood characteristics by multiple-regression methods gave a set of equations that can be used to estimate floods of selected recurrence intervals up to 50 years for any site on any stream in Alaska. The equations relate floods to drainage-basin characteristics. The study indicates that in Alaska the 50-year flood can be estimated from 10-year gaging- station records with a standard error of 22 percent whereas the 50-year flood can be estimated from the regression equation with a standard error of 53 percent. Also, maximum known floods at more than 500 gaging stations and miscellaneous sites in Alaska were related to drainage-area size. An envelope curve of 500 cubic feet per second per square mile covered all but 2 floods in the State.

  1. Using Satellite Measurements of Surface Soil Moisture to Improve Estimates of CO2 and CH4 from Peatlands

    NASA Astrophysics Data System (ADS)

    MacBean, N.; Disney, M.; Gomez-Dans, J.; Lewis, P.; Ineson, P.

    2010-12-01

    Peatlands are important stores of carbon through the partial decomposition of organic matter. However peatlands not only sequester CO2 but they are the main natural source of methane (CH4) due to anaerobic microbial activity under waterlogged conditions. Northern wetlands contribute about 35TgCH4yr-1 [1]. The uncertainty on this estimate is large (from 1mgCH4 m-2 y-1 to 2200mgCH4 m-2 y-1), therefore there is a need to better quantify CH4 emissions and their role in the net carbon balance of peatlands. A correct representation of the hydrology of the system is necessary for modelling CH4 flux as the water table depth controls the area where methanogenic bacteria are active. One of the key variables in the calculation of water table depth is the soil moisture. Soil moisture also affects the decomposition rates of carbon in the soil and influences the water and energy fluxes at the land surface - atmosphere boundary. Microwave measurements of surface soil moisture from satellites can theoretically be used to improve estimates predicted by models. Results from an Observing System Simulation Experiment (OSSE), designed to investigate how observations from satellites may be able to constrain modelled carbon fluxes, are presented. An adapted version of the Carnegie-Ames-Stanford Approach (CASA) model [2] is used that includes a representation of methane dynamics [3]. Synthetic satellite observations of soil moisture are used to update model estimates using a Metropolis Hastings Markov Chain Monte Carlo (MCMC) approach. The effect of temporal frequency and spacing, and precision of observations, is examined with a view to establishing the set of observations that would make a significant improvement in model uncertainty. The results are compared with the system characteristics of existing satellite soil moisture measurements. We believe this is the first attempt to assimilate surface soil moisture into an ecosystem model that includes a full representation of CH4 flux.

  2. Holocene carbon dynamics and radiative forcing of three different types of peatlands in Finland

    NASA Astrophysics Data System (ADS)

    Mathijssen, Paul; Väliranta, Minna; Lohila, Annalea; Minkkinen, Kari; Tuittila, Eeva-Stiina; Tuovinen, Juha-Pekka; Korrensalo, Aino

    2016-04-01

    Peatlands contain approximately a third of all soil carbon globally and as they exchange carbon dioxide (CO2) and methane (CH4) copiously with the atmosphere, changes in peatland carbon budgets have a large impact on the global carbon balance and the concentration of greenhouse gasses in the atmosphere. There has been a growing interest in reconstructing and linking peatland carbon dynamics to past climate variations, because quantitative reconstructions can be used as a basis for future carbon balance predictions. In order to increase our understanding on peatland development and response patterns we quantitatively reconstructed Holocene carbon dynamics of three different peatlands in Finland: a subarctic fen, a boreal peatland complex and a boreal managed pine bog. Several cores from each peatland were investigated. The peatlands showed distinct successional pathways, which were sometimes triggered by fires. Successional stages were partly reflected in carbon accumulation patterns. Sometimes variations in carbon accumulation rates coincided with autogenic changes in peat type and vegetation, but accumulation rates were also related to the large-scale Holocene climate phases. However, Holocene climate changes as such did not seem to result in changes in the peat plant species composition. The mid-Holocene warm and dry climate conditions reduced the carbon accumulation in the subarctic fen and in the fen part of the boreal peatland complex, but when the peatland was in bog phase this effect was not visible. Some bog cores showed a clear increase in carbon accumulation after fen-bog transition, but the pattern was not unanimous. In addition to carbon accumulation, we estimated past CH4 emissions for each peatland respectively by applying different methods and by utilising the established current vegetation-CH4 emission relationship. The reconstructions showed that CH4 emissions always decreased during bog stages, but that the CH4 emissions played a major role in the

  3. Environmental control of methane fluxes over a Danish peatland

    NASA Astrophysics Data System (ADS)

    Herbst, M.; Ringgaard, R.; Friborg, T.; Soegaard, H.

    2009-12-01

    Reducing the greenhouse gas (GHG) emissions from natural and anthropogenic environments has become a key issue over the last decades. In Denmark the management of the wetlands is playing a key role in these attempts. The wetland area of Skjern Meadows in the western part of Denmark is one of the best known examples of peatland restauration in northern Europe. The valley of the Skjern river was restored in 2002, after it had been drained for about 35 years. A micrometeorological instrument mast was erected in the centre of the 2200 ha large area in the summer of 2008, in order to facilitate continuous eddy covariance measurements of the exchange of carbon dioxide and methane between the peatland and the atmosphere. A sonic anemometer (R3, Gill) was used together with a closed-path CO2 analyzer (LI-7000, Li-Cor) and a closed-path CH4 analyzer (DLT-100, Los Gatos). A measurement height of 7 m above the surface ensures that the observed eddy fluxes represent an average signal from the entire peatland. The first year of data collection confirmed the expectation that the area functions as a moderate CO2 sink, whilst it releases methane into the atmosphere. During a 12-months period starting in September 2008, the wetland removed 119 g CO2-C per m2 from the atmosphere and emitted 6 g CH4-C per m2. If the amount of the emitted CH4 is converted into CO2 equivalents, it remained lower than the annual CO2 uptake (188 versus 437 g CO2). This means that the restored peatland functions as a weak greenhouse gas sink, despite its methane production. Whilst the annual CO2 uptake at Skjern Meadows was similar to that reported by Friborg et al. (2003) for a Siberian wetland, the CH4 emission was much lower. The average CO2 and CH4 flux rates were both lower than those estimated for a Dutch wetland by Hendriks et al. (2007). The CH4 emission showed no particular diurnal pattern, but daily rates varied considerably throughout the year. This variability can be correlated to variations

  4. Accretion of southern Alaska

    USGS Publications Warehouse

    Hillhouse, J.W.

    1987-01-01

    Paleomagnetic data from southern Alaska indicate that the Wrangellia and Peninsular terranes collided with central Alaska probably by 65 Ma ago and certainly no later than 55 Ma ago. The accretion of these terranes to the mainland was followed by the arrival of the Ghost Rocks volcanic assemblage at the southern margin of Kodiak Island. Poleward movement of these terranes can be explained by rapid motion of the Kula oceanic plate, mainly from 85 to 43 Ma ago, according to recent reconstructions derived from the hot-spot reference frame. After accretion, much of southwestern Alaska underwent a counterclockwise rotation of about 50 ?? as indicated by paleomagnetic poles from volcanic rocks of Late Cretaceous and Early Tertiary age. Compression between North America and Asia during opening of the North Atlantic (68-44 Ma ago) may account for the rotation. ?? 1987.

  5. Gas bubble transport and emissions for shallow peat from a northern peatland: The role of pressure changes and peat structure

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Slater, Lee

    2015-01-01

    Gas bubbles are an important pathway for methane release from peatlands. The mechanisms controlling gas bubble transport and emissions in peat remain uncertain. The effects of hydrostatic pressure and peat structure on the dynamics of gas bubbles in shallow peat were therefore tested in laboratory experiments. A peat monolith was retrieved from a raised bog and maintained in a saturated state. Three distinct layers were identified from noninvasive permittivity measurements supported by soil physical properties (porosity, bulk density). Phase I of the experiment involved monitoring for the accumulation of gas bubbles under steady pressure and temperature conditions. The data showed evidence for gas bubbles being impeded by a shallow semiconfining layer at depths between 10 and 15 cm. Visible gas bubbles observed on the side of the sample box were recorded over time to estimate changes in the vertical distribution of volumetric gas content. Porosity estimates derived using the Complex Refraction Index Model (CRIM) suggest that gas bubbles enlarge the pore space when the exerted pressure is high enough. Phase II involved triggering release of trapped bubbles by repeatedly increasing and decreasing hydrostatic pressure in an oversaturated condition. Comparison of changes in pressure head and methane density in the head space confirmed that the increasing buoyancy force during drops in pressure is more important for triggering ebullition than increasing mobility during increases in pressure. Our findings demonstrate the importance of changes in hydrostatic pressure on bubble size and variations in resistance of the peat fabric in regulating methane releases from peatlands.

  6. Regional variation of natural peatland pool biogeochemistry and carbon concentrations

    NASA Astrophysics Data System (ADS)

    Turner, Ed; Billett, Mike; Chapman, Pippa; Baird, Andy; Dinsmore, Kerry; Holden, Joseph

    2015-04-01

    Natural open-water pools are a common feature of northern peatlands. They are characterised by low primary production, low pH, and often high concentrations of dissolved organic carbon (DOC). Peatland pools are also sources of atmospheric CH4, and thus have the potential to play an important role in global radiative forcing. Pool environmental variables, particularly water chemistry, vegetation community and physical characteristics, have the potential to exert strong controls on C cycling in pools; however, to our knowledge, no existing studies have addressed the potential variation in pool biogeochemistry and physical characteristics on a regional basis. A total of 66 peatland pools were studied across three regions of the UK (northern Scotland, south-west Scotland, and Northern Ireland) over the period September - October 2013. Vegetation communities, mean depth and basic water chemistry (pH, electrical conductivity and dissolved oxygen) were measured in situ. Water samples were taken for analysis of DOC, POC, DIC, CH4diss, CO2diss(dissolved CO2 and CH4),total N and P, and Cl-, SO42- and NO3-. To evaluate the composition of DOC, UV absorption was measured at 665, 470, 465, 436, 400, 360, 265, 254 nm. We show that many pool variables are significantly different between regions, including DOC, POC and CH4diss. The higher ratio of absorbance at 465 to absorbance at 665nm (E4/E6) for pools in Northern Ireland indicates DOC was sourced from less humified peat, which has implications for the bioavailability and mineralisation of organic carbon. Anion concentrations were significantly higher in the pools in northern Scotland than elsewhere, most likely due to a marine influence. SO42- is a CH4 electron acceptor and thus concentrations may influence methanogenesis. Hierarchical cluster analysis shows clear grouping of the individual pools within each region. PCA analysis showed that pools in SW Scotland were strongly associated with greater vegetative cover (Sphagnum

  7. Temporal and spatial aspects of peatland initiation following deglaciation in North America

    NASA Astrophysics Data System (ADS)

    Gorham, Eville; Lehman, Clarence; Dyke, Arthur; Janssens, Joannes; Dyke, Lawrence

    2007-02-01

    A set of simple ecological models accounts well for the cumulative initiation of peatlands throughout North America in relation to glacial retreat. The most parsimonious form incorporates, first, a delay term to account for the lag during which newly deglaciated land became suitable for peatland initiation and, second, an intrinsic rate of initiation related to the probability of migration and establishment of plant propagules from elsewhere. The goodness of fit of the models, based on 1680 basal-peat dates throughout the continent, allows projection of past trends into the future. Factors contributing to the lag of about 4000 years between deglaciation and peatland initiation are suggested and data on colonization of deglaciated land by beavers (known to initiate peatlands) are presented. The rate of peatland initiation peaked between 7000 and 8000 years ago, but remains appreciable today. A marked depression of peatland initiation (8360-8040 BP) interrupted the peak rate. The time of the interruption matches the 8200 BP cold-dry event recorded in Greenland ice cores, and suggests that this event caused a substantial, continent-wide depression of an important ecosystem function, i.e., carbon sequestration from the atmosphere by peat deposition. Spontaneous initiation of new peatlands is projected to continue for millennia to come.

  8. Greenhouse gas balances in low-productive drained boreal peatlands - is climate-friendly management possible?

    NASA Astrophysics Data System (ADS)

    Ojanen, Paavo; Minkkinen, Kari; Heikkinen, Tiina; Penttilä, Timo

    2016-04-01

    Five million hectares of peatland has been drained for forestry in Finland. About 20% of that, i.e. one million hectares, has been estimated to be so low-productive that the profitability of keeping them in forestry is questionable. At the same time, drainage has introduced changes in the ecosystem functions of these peatlands, including fluxes of greenhouse gases. Options to manage such peatlands include for example 1) no measures, i.e. leaving the drained peatlands as they are 2) increasing intensity by e.g. repetitive fertilisations and 3) restoration back to functional peatlands. Here we estimate the greenhouse gas impacts of these three management options. We collected GHG and organic carbon flux data from 50 low-productive peatlands under these management options over two years 2014-2015. Gas fluxes (CO2, CH4, N2O) were measured with closed chambers. Litter production rates of different plants above and below ground were estimated using litter traps (trees), biomass sampling (roots), through-grow nets (mosses), allometric biomass models (other vasculars) and published turnover rates (roots, other vasculars). Characteristics for estimating tree stand biomass increment were measured at each site from circular sample plots. In this presentation we will estimate the GHG impacts for the different management options, and aim to find the most climate-friendly options for the management of low-productive peatlands in the short and long term. This work was funded by Life+ LIFE12/ENV/FI/150.

  9. 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.

  10. The distribution and amount of carbon in the largest peatland complex in Amazonia

    NASA Astrophysics Data System (ADS)

    Draper, Frederick C.; Roucoux, Katherine H.; Lawson, Ian T.; Mitchard, Edward T. A.; Honorio Coronado, Euridice N.; Lähteenoja, Outi; Torres Montenegro, Luis; Valderrama Sandoval, Elvis; Zaráte, Ricardo; Baker, Timothy R.

    2014-12-01

    Peatlands in Amazonian Peru are known to store large quantities of carbon, but there is high uncertainty in the spatial extent and total carbon stocks of these ecosystems. Here, we use a multi-sensor (Landsat, ALOS PALSAR and SRTM) remote sensing approach, together with field data including 24 forest census plots and 218 peat thickness measurements, to map the distribution of peatland vegetation types and calculate the combined above- and below-ground carbon stock of peatland ecosystems in the Pastaza-Marañon foreland basin in Peru. We find that peatlands cover 35 600 ± 2133 km2 and contain 3.14 (0.44-8.15) Pg C. Variation in peat thickness and bulk density are the most important sources of uncertainty in these values. One particular ecosystem type, peatland pole forest, is found to be the most carbon-dense ecosystem yet identified in Amazonia (1391 ± 710 Mg C ha-1). The novel approach of combining optical and radar remote sensing with above- and below-ground carbon inventories is recommended for developing regional carbon estimates for tropical peatlands globally. Finally, we suggest that Amazonian peatlands should be a priority for research and conservation before the developing regional infrastructure causes an acceleration in the exploitation and degradation of these ecosystems.

  11. Anaerobiosis With and Without Flooding: The Effects of Water Content on Greenhouse Gas Emissions from a Peatland Soil

    NASA Astrophysics Data System (ADS)

    McNicol, G.; Silver, W. L.

    2011-12-01

    Flooded conditions reduce oxygen (O2) availability in peatland soils and can significantly affect greenhouse gas emissions. Consequently, many studies have investigated the effects of peatland water-table level on biogenic gas fluxes. However it may be a conflation to equate flooding with anaerobiosis per se. Humid, finely textured, or organic soils displaying sufficiently high biological activity can deplete soil O2 without flooding, while dissolved O2 in flooded soils may be sufficient to impact soil poising and biogenic gas emissions. We investigated the effects of anaerobiosis, generated with and without soil flooding, on emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). We collected soil from the soil-water-table interface (80-100 cm depth) in a drained peatland that experiences periodic low O2 (< 1 %) availability, and stimulated anaerobiosis with either flooding, and/or an N2 headspace. Gas fluxes were measured 11 times over 3 weeks. We found that CO2 emission ranged from 2.06 ± 0.05 μg C-CO2 gram (g) soil-1 hr-1 under the aerobic, non-flooded treatment to 0.60 ± 0.02 μg C-CO2 g soil-1 hr-1 under the N2-headspace, flooded treatment. Flooding reduced CO2 emission under both headspace treatments (P < 0.001). Nitrous oxide emission was greatest under an aerobic headspace 6.05 ± 0.63 ng N-N2O g soil-1 hr-1 and was negligible with flooding under an N2 headspace. Notably, flooding did not significantly affect N2O emissions under an aerobic headspace but did significantly reduce N2O emission under the N2 headspace; in agreement with the 'hole-in-the-pipe' conceptual model. We observed significant CH4 emission of 1.56 ± 0.26 ng C-CH4 g soil-1 hr-1 only in the flooded, N2 headspace treatment after 17 days of incubation. Our results show that flooding can significantly reduce CO2 emissions, over and above the effect due to O2 depletion. We also found that dissolved O2 can maintain elevated N2O emissions under flooding, likely due to

  12. Carbon pools and accumulation in peatlands of the former Soviet Union

    SciTech Connect

    Botch, M.S.; Kobak, K.I.; Vinson, T.S.

    1995-03-01

    To date, the areal extent, carbon pools, rate of carbon accumulation, and role of peatlands of the former Soviet Union (FSU) in the terrestrial carbon cycle has not been fully recognized. This is a consequence of the fact that may peatlands in the FSU, especially noncommercial peatlands, were never studied and properly mapped. An estimate of the areal extent, carbon pools, and rate of carbon accumulation in peatlands of the FSU obtained by interrelating a number of regional databases and maps, including formerly classified maps, is presented herein. Commercial peatlands were categorized by regional type which facilitated an evaluation of their age and quality. Noncommercial peatlands were evaluated from classified regional topographic maps. Air photographs were used to identify peatlands of northern landscapes. the total peatland area of the FSU was estimated at 165 Mha (10{sup 6} hectares) which was two times greater than the most recent estimates based on thematic maps. The peat carbon pool was estimated at 215 Pg C. Half of this amount was in raised bogs. The rate of peat accumulation varied from 12 g C m{sup -2} yr{sup -1} (polygonal mires) to 72-80 g C m{sup -2} yr{sup -1} (fens and marshes). The total rate of carbon accumulation in FSU peatlands was 52 Tg C yr{sup -1}. Carbon emissions from peat utilization in the FSU were estimated at 122 Tg C yr{sup -1}. Thus, at present, peat accumulation/utilization in the FSU is a net source of approximately 70 Tg C yr{sup -1} to the atmosphere. 45 refs, 1 fig., 3 tabs.

  13. Carbon Distribution and Net Primary Production in a Forest-Peatland Landscape Mosaic

    NASA Astrophysics Data System (ADS)

    Weishampel, P.; Kolka, R.; King, J.

    2007-12-01

    We characterized the distribution of carbon and annual NPP in a mixed forest and peatland landscape in the Marcell Experimental Forest in northern Minnesota, USA. We estimated vegetation biomass and production (aboveground and belowground) and the carbon content of detrital pools (forest floor, woody debris, and mineral soil or peat) in a 1-km2 area that encompassed multiple vegetation cover types, including forested uplands dominated by aspen, mixed-hardwood, or pine, and peatlands dominated by alder, conifers, or ericaceous shrubs and Sphagnum mosses (open peatlands). In aspen dominated areas, which account for >70% of our study area, total C storage was 164 ± 9 Mg C ha-1 while pine and hardwood dominated averaged 190 ± 16 and 153 ± 19 Mg C ha-1 respectively. Total ecosystem carbon content in peatland areas averaged 1380 ± 170 Mg C ha-1 and was highly dependent upon peat depth. Among upland cover types, NPP was greatest in pine-dominated areas (6.2 ± 0.6 Mg C ha-1) and similar in aspen- and hardwood- dominated areas (4.7 ± 0.2 and 4.5 ± 0.5 Mg C ha-1, respectively). We found considerable variability in NPP among peatland cover types; in coniferous peatlands, alder peatlands, and open peatlands, NPP was 6.0, 2.8 ± 0.4 and 1.4 ± 0.2 Mg C ha-1 respectively. Large differences in NPP among peatland cover types as well as smaller but significant differences between deciduous and coniferous upland cover types illustrate the importance of these cover types when scaling carbon cycling to landscape and regional levels.

  14. Peatland simulator connecting drainage, nutrient cycling, forest growth, economy and GHG efflux in boreal and tropical peatlands

    NASA Astrophysics Data System (ADS)

    Lauren, Ari; Hökkä, Hannu; Launiainen, Samuli; Palviainen, Marjo; Lehtonen, Aleksi

    2016-04-01

    Forest growth in peatlands is nutrient limited; principal source of nutrients is the decomposition of organic matter. Excess water decreases O2 diffusion and slows down the nutrient release. Drainage increases organic matter decomposition, CO2 efflux, and nutrient supply, and enhances the growth of forest. Profitability depends on costs, gained extra yield and its allocation into timber assortments, and the rate of interest. We built peatland simulator Susi to define and parameterize these interrelations. We applied Susi-simulator to compute water and nutrient processes, forest growth, and CO2 efflux of forested drained peatland. The simulator computes daily water fluxes and storages in two dimensions for a peatland forest strip located between drainage ditches. The CO2 efflux is made proportional to peat bulk density, soil temperature and O2 availability. Nutrient (N, P, K) release depends on decomposition and peat nutrient content. Growth limiting nutrient is detected by comparing the need and supply of nutrients. Increased supply of growth limiting nutrient is used to quantify the forest growth response to improved drainage. The extra yield is allocated into pulpwood and sawlogs based on volume of growing stock. The net present values of ditch cleaning operation and the gained extra yield are computed under different rates of interest to assess the profitability of the ditch cleaning. The hydrological sub-models of Susi-simulator were first parameterized using daily water flux data from Hyytiälä SMEAR II-site, after which the predictions were tested against independent hydrologic data from two drained peatland forests in Southern Finland. After verification of the hydrologic model, the CO2 efflux, nutrient release and forest growth proportionality hypothesis was tested and model performance validated against long-term forest growth and groundwater level data from 69 forested peatland sample plots in Central Finland. The results showed a clear relation between

  15. Effectiveness and regulatory issues in oil spill bioremediation: Experiences with the Exxon Valdez Oil Spill in Alaska. (Chapter 12). Book chapter

    SciTech Connect

    Pritchard, P.H.

    1993-01-01

    The use of bioremediation as a supplemental cleanup technology in the Exxon Valdez oil spill, in Prince William Sound, Alaska, has proven to be a good example of the problems and successes associated with the practical application in this technology. Field studies conducted by scientists from the U.S. Environmental Protection Agency have demonstrated that oil degradation by indigenous microflora on the beaches of Prince William Sound could be significantly accelerated by adding fertilizer directly to the surfaces of oil-contaminated beaches. The results from the application of an oleophilic fertilizer are presented as exemplary field and laboratory information. The fertilizer enhanced biodegradation of the oil, as measured by changes in oil composition and bulk oil weight per unit of beach material, by approximately twofold relative to untreated controls. These studies supported bioremediation as a useful cleanup alternative that was subsequently used by Exxon on a large scale. They have also generated a number of insightful lessons that have significant relevance to future oil bioremediation efforts. This chapter discusses these lessons and examines complications and difficulties in assessing the effectiveness of bioremediation in the field.

  16. Integrated resource inventory for southcentral Alaska (INTRISCA)

    NASA Technical Reports Server (NTRS)

    Burns, T.; Carson-Henry, C.; Morrissey, L. A.

    1981-01-01

    The Integrated Resource Inventory for Southcentral Alaska (INTRISCA) Project comprised an integrated set of activities related to the land use planning and resource management requirements of the participating agencies within the southcentral region of Alaska. One subproject involved generating a region-wide land cover inventory of use to all participating agencies. Toward this end, participants first obtained a broad overview of the entire region and identified reasonable expectations of a LANDSAT-based land cover inventory through evaluation of an earlier classification generated during the Alaska Water Level B Study. Classification of more recent LANDSAT data was then undertaken by INTRISCA participants. The latter classification produced a land cover data set that was more specifically related to individual agency needs, concurrently providing a comprehensive training experience for Alaska agency personnel. Other subprojects employed multi-level analysis techniques ranging from refinement of the region-wide classification and photointerpretation, to digital edge enhancement and integration of land cover data into a geographic information system (GIS).

  17. Ocean Observing System Demonstrated in Alaska

    NASA Astrophysics Data System (ADS)

    Schoch, G. Carl; Chao, Yi

    2010-05-01

    To demonstrate the utility of an ocean observing and forecasting system with diverse practical applications—such as search and rescue, oil spill response (perhaps relevent to the current Gulf of Mexico oil spill), fisheries, and risk management—a unique field experiment was conducted in Prince William Sound, Alaska, in July and August 2009. The objective was to quantitatively evaluate the performance of numerical models developed for the sound with an array of fixed and mobile observation platforms (Figure 1). Prince William Sound was chosen for the demonstration because of historical efforts to monitor ocean circulation following the 1989 oil spill from the Exxon Valdez tanker. The sound, a highly crenulated embayment of about 10,000 square kilometers at approximately 60°N latitude along the northern coast of the Gulf of Alaska, includes about 6900 kilometers of shoreline, numerous islands and fjords, and an extensive system of tidewater glaciers descending from the highest coastal mountain range in North America. Hinchinbrook Entrance and Montague Strait are the two main deep water connections with the Gulf of Alaska. The economic base of communities in the region is almost entirely resource-dependent. For example, Cordova's economy is based on commercial fishing and Valdez's economy is supported primarily by the trans-Alaska oil pipeline terminal.

  18. 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.

  19. 2012 Alaska Performance Scholarship Outcomes Report

    ERIC Educational Resources Information Center

    Rae, Brian

    2012-01-01

    As set forth in Alaska Statute 14.43.840, Alaska's Departments of Education & Early Development (EED) and Labor and Workforce Development (DOLWD), the University of Alaska (UA), and the Alaska Commission on Postsecondary Education (ACPE) present this first annual report on the Alaska Performance Scholarship to the public, the Governor,…

  20. Alaska Mathematics Standards

    ERIC Educational Resources Information Center

    Alaska Department of Education & Early Development, 2012

    2012-01-01

    High academic standards are an important first step in ensuring that all Alaska's students have the tools they need for success. These standards reflect the collaborative work of Alaskan educators and national experts from the nonprofit National Center for the Improvement of Educational Assessment. Further, they are informed by public…

  1. ECOREGIONS OF ALASKA

    EPA Science Inventory

    A map of ecoregions of Alaska has been produced as a framework for organizing and interpreting environmental data for state, national, and international inventory, monitoring, and research efforts. he map and descriptions for 20 ecological regions were derived by synthesizing inf...

  2. Customer Service in Alaska.

    ERIC Educational Resources Information Center

    Ogliore, Judy

    1997-01-01

    Examines how the child support enforcement program in Alaska has responded to the challenges of distance, weather, and cultural differences through training representatives, making waiting areas more comfortable, conducting random customer evaluation of services, establishing travel hubs in regional offices and meeting with community leaders and…

  3. Current Ethnomusicology in Alaska.

    ERIC Educational Resources Information Center

    Johnston, Thomas F.

    The systematic study of Eskimo, Indian, and Aleut musical sound and behavior in Alaska, though conceded to be an important part of white efforts to foster understanding between different cultural groups and to maintain the native cultural heritage, has received little attention from Alaskan educators. Most existing ethnomusical studies lack one or…

  4. Alaska's Cold Desert.

    ERIC Educational Resources Information Center

    Brune, Jeff; And Others

    1996-01-01

    Explores the unique features of Alaska's Arctic ecosystem, with a focus on the special adaptations of plants and animals that enable them to survive in a stressful climate. Reviews the challenges facing public and private land managers who seek to conserve this ecosystem while accommodating growing demands for development. Includes classroom…

  5. Alaska Glaciers and Rivers

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image on October 7, 2007, showing the Alaska Mountains of south-central Alaska already coated with snow. Purple shadows hang in the lee of the peaks, giving the snow-clad land a crumpled appearance. White gives way to brown on the right side of the image where the mountains yield to the lower-elevation Susitna River Valley. The river itself cuts a silver, winding path through deep green forests and brown wetlands and tundra. Extending from the river valley, are smaller rivers that originated in the Alaska Mountains. The source of these rivers is evident in the image. Smooth white tongues of ice extend into the river valleys, the remnants of the glaciers that carved the valleys into the land. Most of the water flowing into the Gulf of Alaska from the Susitna River comes from these mountain glaciers. Glacier melt also feeds glacier lakes, only one of which is large enough to be visible in this image. Immediately left of the Kahiltna River, the aquamarine waters of Chelatna Lake stand out starkly against the brown and white landscape.

  6. Alaska and Yukon Fires

    Atmospheric Science Data Center

    2014-05-15

    article title:  Smoke Signals from the Alaska and Yukon Fires   ... the Yukon Territory from mid-June to mid-July, 2004. Thick smoke particles filled the air during these fires, prompting Alaskan officials to issue air quality warnings. Some of the smoke from these fires was detected as far away as New Hampshire. These ...

  7. Suicide in Northwest Alaska.

    ERIC Educational Resources Information Center

    Travis, Robert

    1983-01-01

    Between 1975 and 1979 the Alaskan Native suicide rate (90.9 per 100,000) in Northwest Alaska was more than seven times the national average. Alienation, loss of family, low income, alcohol abuse, high unemployment, and more education were factors related to suicidal behavior. Average age for suicidal behavior was 22.5. (Author/MH)

  8. Fractionation of (137)Cs and Pu in natural peatland.

    PubMed

    Mihalík, Ján; Bartusková, Miluše; Hölgye, Zoltán; Ježková, Tereza; Henych, Ondřej

    2014-08-01

    High Cs-137 concentrations in plants growing on peatland inspired us to investigate the quantity of its bioavailable fraction in natural peat. Our investigation aims to: a) estimate the quantity of bioavailable Cs-137 and Pu present in peat, b) verify the similarity of Cs-137 and K-40 behaviours, and c) perform a quantification of Cs-137 and Pu transfer from peat to plants. We analysed the vertical distribution of Cs-137 and Pu isotopes in the peat and their concentrations in plants growing on these places. Bioavailability of radionuclides was investigated by sequential extraction. Sequential analyses revealed that it was the upper layer which contained the majority of Cs-137 in an available form while deeper layers retained Cs-137 in immobile fractions. We can conclude that 18% of all Cs-137 in the peat is still bioavailable. Despite of the low quantity of bioavailable fraction of Cs-137 its transfer factor reached extremely high values. In the case of Pu, 64% of its total amount was associated with fulvic/humic acids which resulted in the high transfer factor from peat to plants. 27 years after the Chernobyl nuclear accident, the significant part of radionuclides deposited in peatland is still bioavailable. PMID:24631917

  9. River Ecosystem Response to Prescribed Vegetation Burning on Blanket peatland

    PubMed Central

    Brown, Lee E.; Johnston, Kerrylyn; Palmer, Sheila M.; Aspray, Katie L.; Holden, Joseph

    2013-01-01

    Catchment-scale land-use change is recognised as a major threat to aquatic biodiversity and ecosystem functioning globally. In the UK uplands rotational vegetation burning is practised widely to boost production of recreational game birds, and while some recent studies have suggested burning can alter river water quality there has been minimal attention paid to effects on aquatic biota. We studied ten rivers across the north of England between March 2010 and October 2011, five of which drained burned catchments and five from unburned catchments. There were significant effects of burning, season and their interaction on river macroinvertebrate communities, with rivers draining burned catchments having significantly lower taxonomic richness and Simpson’s diversity. ANOSIM revealed a significant effect of burning on macroinvertebrate community composition, with typically reduced Ephemeroptera abundance and diversity and greater abundance of Chironomidae and Nemouridae. Grazer and collector-gatherer feeding groups were also significantly less abundant in rivers draining burned catchments. These biotic changes were associated with lower pH and higher Si, Mn, Fe and Al in burned systems. Vegetation burning on peatland therefore has effects beyond the terrestrial part of the system where the management intervention is being practiced. Similar responses of river macroinvertebrate communities have been observed in peatlands disturbed by forestry activity across northern Europe. Finally we found river ecosystem changes similar to those observed in studies of wild and prescribed forest fires across North America and South Africa, illustrating some potentially generic effects of fire on aquatic ecosystems. PMID:24278367

  10. Global vulnerability of peatlands to fire and carbon loss

    NASA Astrophysics Data System (ADS)

    Turetsky, Merritt R.; Benscoter, Brian; Page, Susan; Rein, Guillermo; van der Werf, Guido R.; Watts, Adam

    2015-01-01

    Globally, the amount of carbon stored in peats exceeds that stored in vegetation and is similar in size to the current atmospheric carbon pool. Fire is a threat to many peat-rich biomes and has the potential to disturb these carbon stocks. Peat fires are dominated by smouldering combustion, which is ignited more readily than flaming combustion and can persist in wet conditions. In undisturbed peatlands, most of the peat carbon stock typically is protected from smouldering, and resistance to fire has led to a build-up of peat carbon storage in boreal and tropical regions over long timescales. But drying as a result of climate change and human activity lowers the water table in peatlands and increases the frequency and extent of peat fires. The combustion of deep peat affects older soil carbon that has not been part of the active carbon cycle for centuries to millennia, and thus will dictate the importance of peat fire emissions to the carbon cycle and feedbacks to the climate.

  11. Medium term ecohydrological response of peatland bryophytes to canopy disturbance

    NASA Astrophysics Data System (ADS)

    Leonard, Rhoswen; Kettridge, Nick; Krause, Stefan; Devito, Kevin; Granath, Gustaf; Petrone, Richard; Mandoza, Carl; Waddington, James Micheal

    2016-04-01

    Canopy disturbance in northern forested peatlands is widespread. Canopy changes impact the ecohydrological function of moss and peat, which provide the principal carbon store within these carbon rich ecosystems. Different mosses have contrasting contributions to carbon and water fluxes (e.g. Sphagnum fuscum and Pleurozium schreberi) and are strongly influenced by canopy cover. As a result, changes in canopy cover lead to long-term shifts in species composition and associated ecohydrological function. Despite this, the medium-term response to such disturbance, the associated lag in this transition to a new ecohydrological and biogeochemical regime, is not understood. Here we investigate this medium term ecohydrological response to canopy removal using a randomised plot design within a north Albertan peatland. We show no significant ecohydrological change in treatment plots four years after canopy removal. Notably, Pleurozium schreberi and Sphagnum fuscum remained within respective plots post treatment and there was no significant difference in plot resistance to evapotranspiration or carbon exchange. Our results show that canopy removal alone has little impact on bryophyte ecohydrology in the short/medium term. This resistance to disturbance contrasts strongly with dramatic short-term changes observed within mineral soils suggesting that concurrent shifts in the large scale hydrology induced within such disturbances are necessary to cause rapid ecohydrological transitions. Understanding this lagged response is critical to determine the decadal response of carbon and water fluxes in response to disturbance and the rate at which important medium term ecohydrological feedbacks are invoked.

  12. Opportunities for reducing greenhouse gas emissions in tropical peatlands

    PubMed Central

    Murdiyarso, D.; Hergoualc’h, K.; Verchot, L. V.

    2010-01-01

    The upcoming global mechanism for reducing emissions from deforestation and forest degradation in developing countries should include and prioritize tropical peatlands. Forested tropical peatlands in Southeast Asia are rapidly being converted into production systems by introducing perennial crops for lucrative agribusiness, such as oil-palm and pulpwood plantations, causing large greenhouse gas (GHG) emissions. The Intergovernmental Panel on Climate Change Guidelines for GHG Inventory on Agriculture, Forestry, and Other Land Uses provide an adequate framework for emissions inventories in these ecosystems; however, specific emission factors are needed for more accurate and cost-effective monitoring. The emissions are governed by complex biophysical processes, such as peat decomposition and compaction, nutrient availability, soil water content, and water table level, all of which are affected by management practices. We estimate that total carbon loss from converting peat swamp forests into oil palm is 59.4 ± 10.2 Mg of CO2 per hectare per year during the first 25 y after land-use cover change, of which 61.6% arise from the peat. Of the total amount (1,486 ± 183 Mg of CO2 per hectare over 25 y), 25% are released immediately from land-clearing fire. In order to maintain high palm-oil production, nitrogen inputs through fertilizer are needed and the magnitude of the resulting increased N2O emissions compared to CO2 losses remains unclear. PMID:21081702

  13. River ecosystem response to prescribed vegetation burning on Blanket Peatland.

    PubMed

    Brown, Lee E; Johnston, Kerrylyn; Palmer, Sheila M; Aspray, Katie L; Holden, Joseph

    2013-01-01

    Catchment-scale land-use change is recognised as a major threat to aquatic biodiversity and ecosystem functioning globally. In the UK uplands rotational vegetation burning is practised widely to boost production of recreational game birds, and while some recent studies have suggested burning can alter river water quality there has been minimal attention paid to effects on aquatic biota. We studied ten rivers across the north of England between March 2010 and October 2011, five of which drained burned catchments and five from unburned catchments. There were significant effects of burning, season and their interaction on river macroinvertebrate communities, with rivers draining burned catchments having significantly lower taxonomic richness and Simpson's diversity. ANOSIM revealed a significant effect of burning on macroinvertebrate community composition, with typically reduced Ephemeroptera abundance and diversity and greater abundance of Chironomidae and Nemouridae. Grazer and collector-gatherer feeding groups were also significantly less abundant in rivers draining burned catchments. These biotic changes were associated with lower pH and higher Si, Mn, Fe and Al in burned systems. Vegetation burning on peatland therefore has effects beyond the terrestrial part of the system where the management intervention is being practiced. Similar responses of river macroinvertebrate communities have been observed in peatlands disturbed by forestry activity across northern Europe. Finally we found river ecosystem changes similar to those observed in studies of wild and prescribed forest fires across North America and South Africa, illustrating some potentially generic effects of fire on aquatic ecosystems. PMID:24278367

  14. The effect of long-term water table manipulations on dissolved organic carbon dynamics in a poor fen peatland

    NASA Astrophysics Data System (ADS)

    Hribljan, John A.; Kane, Evan S.; Pypker, Thomas G.; Chimner, Rodney A.

    2014-04-01

    Dissolved organic carbon (DOC) production, consumption, and quality displayed differences after long-term (~55 years) hydrological alterations in a poor fen peatland in northern Michigan. The construction of an earthen levee resulted in areas of a raised and lowered water table (WT) relative to an unaltered intermediate WT site. The lowered WT site had greater peat aeration and larger seasonal vertical WT fluctuations that likely elevated peat decomposition and subsidence with subsequent increases in bulk density, vertical hydraulic gradient, decreased hydraulic conductivity (Ksat), and a greater pore water residence time relative to the unaltered site. The raised WT site displayed a decreased Ksat combined with seasonal upwelling events that contributed to a longer residence time in comparison to the unaltered site. These differences are potentially contributing to elevated DOC concentrations at the lowered and raised WT site relative to the unaltered site. Additionally, spectrophotometric indices and chemical constituent assays indicated that the lowered site DOC was more aromatic and contained elevated concentrations of phenolics compared to the intermediate site. The raised site DOC was less aromatic, less humified, and also had a greater phenolic content than the intermediate site. Furthermore, an incubation experiment showed that DOC in the raised site contained the greatest labile carbon source. Based on our results, long-term WT alterations will likely impose significant effects on DOC dynamics in these peatlands; however, WT position alone was not a good predictor of DOC concentrations, though impoundment appears to produce a more labile DOC whereas drainage increases DOC aromaticity.

  15. A decade of continuous NEE measurements at a Scottish peatland

    NASA Astrophysics Data System (ADS)

    Helfter, Carole; Campbell, Claire; Coyle, Mhairi; Anderson, Margaret; Drewer, Julia; Levy, Peter; Famulari, Daniela; Twigg, Marsailidh; Skiba, Ute; Billett, Michael; Dinsmore, Kerry; Nemitz, Eiko; Sutton, Mark

    2013-04-01

    Eddy-covariance measurements of carbon dioxide (CO2) fluxes have been running continuously at the Auchencorth Moss peatland site in Scotland (55o47'32N, 3o14'35W, 267 m a.s.l.) since the spring of 2002 which makes this study one of the longest ones to date on a peatland system. Auchencorth Moss is a low-lying, ombrotrophic peatland situated ca. 20 km south-west of Edinburgh. Peat depth ranges from <0.5 m to >0.5 m and the site has a mean annual precipitation of 1155 mm. The open moorland site has an extensive uniform fetch of blanket bog to the south, west and north. The vegetation present within the flux measurement footprint comprises mixed grass species, heather and substantial areas of moss species (Sphagnum spp. and Polytrichum spp.). The eddy-covariance system consists of a Licor 7000 closed-path infrared gas analyser operating at 10 Hz for the simultaneous measurement of carbon dioxide and water vapour and of a Gill Windmaster Pro ultrasonic anemometer, operating at 20 Hz, and mounted atop a 3 m mast. The effective measurement height is 3.5 m with a vertical separation of 20 cm between the anemometer and the inlet of the sampling line. Air is sampled at 20 litres per minute through a 40 m long Dekabon line (internal diameter 4 mm). In addition to eddy-covariance measurements, the site is equipped with a weather station, soil temperature measurements, total solar radiation and photosynthetically active radiation (PAR) sensors, a tipping bucket for rainfall and, since April 2007, water table depth has been recorded at half-hourly interval. On an annual basis, the peatland at Auchencorth Moss has consistently been a net sink of CO2 in the study period 2002-2012 with a mean net ecosystem exchange (NEE) of - 69.1 ± 33.6 g C-CO2 m-2 yr-1. This value is at the high end of other recent studies as is the inter-annual range of NEE (-31.4 to -135.9 g C-CO2 m-2 yr-1). Inter-annual variations in NEE are significant and strongly correlated to the length of the growing

  16. Asthma and American Indians/Alaska Natives

    MedlinePlus

    ... Minority Population Profiles > American Indian/Alaska Native > Asthma Asthma and American Indians/Alaska Natives In 2014, 218, ... Native American adults reported that they currently have asthma. American Indian/Alaska Native children are 30% more ...

  17. The diversity of microfungi in peatlands originated from the White Sea.

    PubMed

    Grum-Grzhimaylo, Olga A; Debets, Alfons J M; Bilanenko, Elena N

    2016-01-01

    The diversity of culturable filamentous microfungi in peat and sediments of four peatlands at the coastal zone of Kandalaksha Bay of the White Sea (Murmansk region, Russia) was studied by culture methods on standard and selective media. Annually 100 samples were collected from the bogs 2007-2010. Based on morphological, molecular markers and cultural features, 211 taxa were identified. Fungal communities observed at the peatlands were influenced mostly by their sea origin. We discovered a large difference between fungal communities from the peat and the sediments of the peatlands. In contrast to the sediments, the fungal community of the peat was found to be consistent throughout sampling sites. Fungi with specific ecophysiology, such as Sphagnum-decomposing species (Oidiodendron griseum, O. tenuissimum. Penicillium spinulosum, P. thomii, Talaromyces funiculosus), psychrotolerant and associated with insects species (Pseudogymnoascus pannorum, Tolypocladium spp.), typical marine species (Acremonium spp.) were found. In addition, different types of sterile mycelia were characteristic for the researched peatlands. PMID:26742584

  18. Carbon storage and release in Indonesian peatlands since the last deglaciation

    NASA Astrophysics Data System (ADS)

    Dommain, René; Couwenberg, John; Glaser, Paul H.; Joosten, Hans; Suryadiputra, I. Nyoman N.

    2014-08-01

    Peatlands have been recognised as globally important carbon sinks over long timescales that produced a global, net-climatic cooling effect over the Holocene. However, little is known about the role of tropical peatlands in the global carbon cycle. We therefore determine the past rates of carbon storage and release in the Indonesian peatlands of Kalimantan and Sumatra - the largest global concentration of tropical peatlands - since 20 ka (kiloannum before present). Using a novel GIS (geographic information system) approach we provide a spatially-explicit reconstruction of peatland expansion in a series of paleogeographic maps. Sea-level change is identified as the principal driver for peatland formation and expansion in western Indonesia as it controls both atmospheric moisture supply and the hydrological gradient on the islands. Initiation of inland peatlands in Kalimantan was coupled to periods of rapid deglacial sea-level rise with rates of over 10 mm yr-1 whereas coastal peatlands could only form after 7 ka when the rate of sea-level rise had slowed to 2.4 mm yr-1. Falling sea levels after 5 ka led to rapid peatland expansion in coastal lowlands and a doubling of the total peatland area in western Indonesia to 131,500 km2 between 2.3 ka and 0 ka. As a result of slow peatland expansion from 15 to 6 ka and rapid expansion afterwards the rate of annual carbon storage of all western Indonesian peatlands remained <1 Tg C yr-1 until 6 ka and then increased to 7.2 Tg C yr-1 by 0 ka. Associated with this rise in carbon storage was an exponential growth of the peat carbon pool from 0.01 Pg C by 15 ka to 23.2 Pg C at present, of which 70% is stored in coastal peatlands. In inland Kalimantan peatlands, falling sea levels together with increased El Niño activity induced an annual carbon release of 0.15 Tg C yr-1 from aerobic peat decay since 2 ka. Cumulative carbon losses from anaerobic decomposition do not seem to limit peat bog growth in the tropical peatlands of

  19. Influence of Water Table Depth on Pore Water Chemistry and Trihalomethane Formation Potential in Peatlands.

    PubMed

    Gough, Rachel; Holliman, Peter J; Fenner, Nathalie; Peacock, Mike; Freeman, Christopher

    2016-02-01

    Drained peatland catchments are reported to produce more colored, dissolved organic carbon (DOC)-rich water, presenting problems for potable water treatment. The blocking of peatland drainage ditches to restore the water table is increasingly being considered as a strategy to address this deterioration in water quality. However, the effect of ditch blocking on the potential of DOC to form trihalomethanes (THMs) has not been assessed. In this study, the effect of peat rewetting on pore water DOC concentration and characteristics (including THM formation potential [THMFP]) was assessed over 12 months using peat cores collected from two drained peatland sites. The data show little evidence of differences in DOC concentration or characteristics between the different treatments. The absence of any difference in the THMFP of pore water between treatments suggests that, in the short term at least, ditch blocking may not have an effect on the THMFP of waters draining peatland catchments. PMID:26803099

  20. Untangling climate signals from autogenic changes in long-term peatland development

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Peatlands represent important archives of Holocene paleoclimatic information. However, autogenic processes may disconnect peatland hydrological behavior from climate and overwrite climatic signals in peat records. We use a simulation model of peatland development driven by a range of Holocene climate reconstructions to investigate climate signal preservation in peat records. Simulated water-table depths and peat decomposition profiles exhibit homeostatic recovery from prescribed changes in rainfall, whereas changes in temperature cause lasting alterations to peatland structure and function. Autogenic ecohydrological feedbacks provide both high- and low-pass filters for climatic information, particularly rainfall. Large-magnitude climatic changes of an intermediate temporal scale (i.e., multidecadal to centennial) are most readily preserved in our simulated peat records. Simulated decomposition signals are offset from the climatic changes that generate them due to a phenomenon known as secondary decomposition. Our study provides the mechanistic foundations for a framework to separate climatic and autogenic signals in peat records.

  1. Tropical peatland carbon dynamics simulated for scenarios of disturbance and restoration and climate change

    NASA Astrophysics Data System (ADS)

    Frolking, S. E.; Warren, M.; Dai, Z.; Kurnianto, S.; Hagen, S. C.

    2015-12-01

    Tropical peatlands contain a globally significant carbon pool. Southeast Asian peatlands are being deforested, drained and burned at very high rates, mostly for conversion to industrial oil palm or pulp and paper plantations. The climate mitigation potential of tropical peatlands has gained increasing attention in recent years as persistent greenhouse gas emissions can be avoided or decreased if peatlands remain intact or are rehabilitated. In addition, peatland conservation or rehabilitation for climate mitigation also includes multiple co-benefits such as maintenance of ecosystem services, biodiversity, and air quality from reduced fire occurrence. Inventory guidelines and methodologies have only recently become available, and are based on few data from a limited number of sites. Few heuristic tools are available to evaluate the impact of management practices on carbon dynamics in tropical peatlands, and the potential climate mitigation benefits of peatland restoration. We used a process based dynamic tropical peatland model to explore the C dynamics of several peatland management trajectories represented by hypothetical scenarios, within the context of simulated 21st century climate change. All scenarios with land use, including those with optimal restoration, simulate C loss over the 21st century, with C losses ranging from 10% to essentially 100% of pre-disturbance values. Fire, either prescribed as part of a crop rotation cycle, or stochastic occurrences in sub-optimally managed degraded land can be the dominant C-loss pathway, particularly in the drier climate scenario we tested. A single 25-year oil palm rotation, with a prescribed initial burn, lost 40-50 kg C/m2, equivalent to accumulation during the previous 500 years, 10-30% of which was restored in 75 years of optimal restoration. Our results indicate that even under the most optimistic scenario of hydrological and forest restoration and the wettest climate regime, only about one-third of the carbon

  2. CO2 and CH4 fluxes of an Alpine peatland during extraordinary summer drought

    NASA Astrophysics Data System (ADS)

    Drollinger, Simon; Glatzel, Stephan

    2016-04-01

    In peatland ecosystems, plant production exceeds decomposition due to their typical characteristic of waterlogged soils leading to peatland growth and an accumulation of thick organic soil layers. As a result, peatlands constitute a major global storage of carbon (C) by storing about 612 PgC in their peat, thus representing the most space-effective C stocks of all terrestrial ecosystems, similar in magnitude as the increasing atmospheric C pool (~ 850 PgC). However, little is known about the effects of climate change on peatlands and the contribution of Alpine peatlands as a source of greenhouse gases in the course of a changing climate. It is debatable how land-use changes and ongoing degradation of Alpine peatlands affect the peatland-atmosphere C exchange. On the one hand, more C may sequester due to increased plant growth in a warmer climate, on the other hand large amounts of respired C may release as a consequence of higher temperatures and lowered peatland water table depths due to increasing evaporation rates and extending drought periods. To examine the potential effects of climate change on the peatland carbon exchange with the atmosphere, we calculated CO2 and CH4 fluxes using the eddy covariance method. The investigated ombrotrophic peatland is located on the bottom of the Styrian Enns valley at an altitude of 632 m above sea level. It is a slightly degraded pine peat bog (62 ha) with a closed peat moss cover featuring the three plant associations Pino mugo-Sphagnetum magellanici, Sphagnetum magellanici, and Caricetum limosae, according to the prevailing hydrological site conditions. During summer drought in 2015, the water level decreased from an annual average water level of -10.44 cm to -28.50 cm below surface at the centre of the peat bog. Here, we present diurnal pattern of CO2 and CH4 fluxes during an extraordinary dry summer and compare them to calculated fluxes during periods characterised by precipitation and higher peat water levels of the

  3. Effect of long-term drainage of peatland on whole-profile microbial community structure

    NASA Astrophysics Data System (ADS)

    Mpamah, Promise; Taipale, Sami; Rissanen, Antti; Biasi, Christina; Nykänen, Hannu

    2015-04-01

    Peatlands are crucial global carbon stores largely due to prevailing hydrological regime leading to higher rate of carbon input than loss. Like other changes in environmental conditions, alteration in peatland water table, which causes increased aeration in the upper layer, does not only cause a shift in this exchange rates, but leads to changes in plant species cover, litter quality as well as the niches of microbes, by affecting their functions and activities. Effects of changes in peatland hydrology are therefore complex, and play a key role in peat carbon cycles. Changed peat hydrology may especially affect the inter-play between methanogens and methanotrophs which are important members of the microbial community taking part in anaerobic/aerobic peatland carbon cycles. We provide more information on the effect of long-term (more than 33 years) changes in hydrology on the whole-peat-profile microbes, from top to bottom. We studied drained and adjacent non-drained peatlands in Lakkasuo mire complex and Lammi area of Finland, which differed in vegetation cover and management history. We focused majorly on the phospholipid fatty acids (PLFA) analysis as an indicator of the overall microbial community structure, but also used DNA analysis to mainly compare the methane oxidizing bacteria (MOB) of the different peatland types with different vegetation. Our PLFA results showed that peat mire complexes are more similar in their microbial community, within location and profiles than between locations irrespective of hydrological changes and types or vegetation covers. PLFA and DNA analysis also showed that MOB species belonging to type II were more dominant than those of type I in both locations studied. Our study also showed that long-term draining of peatlands does not change the biomass of soil microbial communities, but alters their structural or relative composition. The effect of long-term peatland drainage is mostly located at the surface. Depth gradient effects

  4. Insights from 14C into C loss pathways in degraded peatlands

    NASA Astrophysics Data System (ADS)

    Evans, Martin; Evans, Chris; Allott, Tim; Stimson, Andrew; Goulsbra, Claire

    2016-04-01

    Peatlands are important global stores of terrestrial carbon. Lowered water tables due to changing climate and direct or indirect human intervention produce a deeper aerobic zone and have the potential to enhance loss of stored carbon from the peat profile. The quasi continuous accumulation of organic matter in active peatlands means that the age of fluvial dissolved organic carbon exported from peatland systems is related to the source depth in the peat profile. Consequently 14C analysis of DOC in waters draining peatlands has the potential not only to tell us about the source of fluvial carbon and the stability of the peatland but also about the dominant hydrological pathways in the peatland system. This paper will present new radiocarbon determinations from peatland streams draining the heavily eroded peatlands of the southern Pennine uplands in the UK. These blanket peatland systems are highly degraded, with extensive bare peat and gully erosion resulting from air pollution during the industrial revolution, overgrazing, wildfire and climatic changes. Deep and extensive gullying has significantly modified the hydrology of these systems leading to local and more widespread drawdown of water table. 14C data from DOC in drainage waters are presented from two catchments; one with extensive gully erosion and the other with a combination of gully erosion and sheet erosion of the peat. At the gully eroded site DOC in drainage waters is as old as 160 BP but at the site with extensive sheet erosion dates of up to 1069 BP are amongst the oldest recorded from blanket peatland globally These data indicate significant degradation of stored carbon from the eroding peatlands. Initial comparisons of the 14C data with modelled water table for the catchments and depth-age curves for catchment peats suggests that erosion of the peat surface, allowing decomposition of exposed older organic material is a potential mechanism producing aged carbon from the eroded catchment. This

  5. Emissions of methane from northern peatlands: a review of management impacts and future implications

    NASA Astrophysics Data System (ADS)

    Abdalla, Mohamed; Hastings, Astley; Mander, Ulo; Smith, Pete; Nilsson, Mats

    2016-04-01

    Northern peatlands constitute a significant source of atmospheric methane (CH4). However, management of undisturbed peatlands, as well as restoration of disturbed peatlands, will alter the exchange of methane with the atmosphere. The aim of this literature review and meta-analysis was to collate and analyse recent literature to improve our understanding of the impacts of management on CH4 emissions from northern peatlands i.e. latitude 40 to 70o N. Results show that CH4 emissions from natural northern peatlands range from 0 to 154 g C m-2 yr-1 and the overall annual average (mean ± standard deviation) is 11.7 ± 21 g C m-2 yr-1 with the highest emissions from fen ecosystems. Drainage significantly (p<0.05) reduces CH4 emissions to the atmosphere, on average by 84%. However, restoration by rewetting of peatlands and application of N fertilizer both significantly (p<0.05) increase the emissions compared to the original pre-management CH4 fluxes. Methane emissions are mainly controlled by water table (WT) depth, plant community composition and soil pH. Although temperature is not a good predictor of CH4 emissions by itself, the interaction between temperatures, plant community cover, WT depth and soil pH is important. According to short-term forecasts of climate change, these complex interactions will be the main determinant of increased CH4 emissions from northern peatlands. However, to fully evaluate the net effect of management practice on high latitude peatlands both net ecosystem exchange (NEE) and carbon exports needs to be considered.

  6. 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.

  7. Assessing water table dynamics of peatland areas using Landsat TIR imagery

    NASA Astrophysics Data System (ADS)

    Carrión Klier, Carolina; Schuetz, Tobias; Untenecker, Johanna; Bechtold, Michel

    2016-04-01

    Water saturation conditions in peatlands are a driving factor for the emission of greenhouse gases. Thus, the identification of long-term saturation dynamics in peatland areas is a first step towards the quantification of emissions from these ecosystems. Unfortunately, information on groundwater levels is not always available on the necessary spatial or temporal resolution. Publicly available databases of remotely sensed satellite data offer ways to close this lack of information. Previous studies have shown the potential of the thermal signature of the soil surface monitored by thermal infrared imagery to derive information about subsurface hydrology. It is also known that shallow-groundwater systems as wet peatlands are less susceptible to seasonal temperature fluctuations than drained peatlands and soils with deeper groundwater. Hence, wetter peatlands will be characterized by a smoother seasonal surface temperature curve, being cooler in the summer and warmer in the winter. Due to the strong influence of the vegetation cover on thermal infrared radiative transfer, we here analyze temperature dynamics as relative differences between comparable vegetation cover in the same region. As satellite data we used remotely sensed Landsat TIR imagery. The archive of Landsat TIR imagery compiles records on a 16 days cycle since 1984. The present study seeks to use this archive to reconstruct the water saturation conditions in the peatland areas of the state of Baden-Wuerttemberg, Germany, over the last three decades. We restricted our analysis on grassland vegetation because of its predominance in the study area and its relative low vegetation height. Preliminary results for selected peatlands are 1) peatland characteristic annual patterns of TIR temperature differences, and 2) intra-annual variability over the years of available Landsat imagery within these patterns. In our presentation, we will further compare the resulting time series with available groundwater level

  8. Sources and Age of Aquatic DOC, CO2 And CH4 Exported From a Swedish Peatland

    NASA Astrophysics Data System (ADS)

    Campeau, A.; Wallin, M.; Billett, M. F.; Nilsson, M. B.; Laudon, H.; Oquist, M. G.; Bishop, K. H.

    2015-12-01

    Northern peatlands store as much organic matter as the equivalent of all the CO2 currently present in the earth's atmosphere. The peat carbon storage results from the progressive accumulation of organic matter since the end of the last glaciation (~10 000 years). The stability of these large carbon storages, under the influence of climate change, is unknown. Runoff represents one of the major C fluxes out of northern peatlands, and is particularly sensitive to changes in climate and hydrological regimes. Identifying the sources and age of aquatic C export will help assess the stability and future role of northern peatlands as active components of the global C cycle. We have characterized both radiogenic (14C) and stable carbon isotopes (δ13C) of DOC, CO2 and CH4 across a four-meter deep ombrotrophic peatland and its stream outlet. Previous studies have shown that about 34% of the estimated net ecosystem exchange from this peatland system, is lost through aquatic C export. We determined that fermentation processes in the peat acts as the main production pathway for stream CO2 (mean δ13C =-4.9‰) and CH4 (mean δ13C = -67.8‰). The seasonal variability in both sources and age of C was high. Despite this dynamism, the application of carbon isotopes allowed us to trace back the origin of aquatic C exports from the peatland.

  9. Subsidence Rates of Drained Agricultural Peatlands in New Zealand and the Relationship with Time since Drainage.

    PubMed

    Pronger, Jack; Schipper, Louis A; Hill, Reece B; Campbell, David I; McLeod, Malcolm

    2014-07-01

    The drainage and conversion of peatlands to productive agro-ecosystems leads to ongoing surface subsidence because of densification (shrinkage and consolidation) and oxidation of the peat substrate. Knowing the ra0te of this surface subsidence is important for future land-use planning, carbon accounting, and economic analysis of drainage and pumping costs. We measured subsidence rates over the past decade at 119 sites across three large, agriculturally managed peatlands in the Waikato region, New Zealand. The average contemporary (2000s-2012) subsidence rate for Waikato peatlands was 19 ± 2 mm yr (± SE) and was significantly less ( = 0.01) than the historic rate of 26 ± 1 mm yr between the 1920s and 2000s. A reduction in the rate of subsidence through time was attributed to the transition from rapid initial consolidation and shrinkage to slower, long-term, ongoing oxidation. These subsidence rates agree well with a literature synthesis of temperate zone subsidence rates reported for similar lengths of time since drainage. A strong nonlinear relationship was found between temperate zone subsidence rates and time since initial peatland drainage: Subsidence (mm yr) = 226 × (years since drained) ( = 0.88). This relationship suggests that time since drainage exerts strong control over the rate of peatland subsidence and that ongoing peatland subsidence rates can be predicted to gradually decline with time in the absence of major land disturbance. PMID:25603091

  10. Vulnerability of the peatland carbon sink to sea-level rise.

    PubMed

    Whittle, Alex; Gallego-Sala, Angela V

    2016-01-01

    Freshwater peatlands are carbon accumulating ecosystems where primary production exceeds organic matter decomposition rates in the soil, and therefore perform an important sink function in global carbon cycling. Typical peatland plant and microbial communities are adapted to the waterlogged, often acidic and low nutrient conditions that characterise them. Peatlands in coastal locations receive inputs of oceanic base cations that shift conditions from the environmental optimum of these communities altering the carbon balance. Blanket bogs are one such type of peatlands occurring in hyperoceanic regions. Using a blanket bog to coastal marsh transect in Northwest Scotland we assess the impacts of salt intrusion on carbon accumulation rates. A threshold concentration of salt input, caused by inundation, exists corresponding to rapid acidophilic to halophilic plant community change and a carbon accumulation decline. For the first time, we map areas of blanket bog vulnerable to sea-level rise, estimating that this equates to ~7.4% of the total extent and a 0.22 Tg yr(-1) carbon sink. Globally, tropical peatlands face the proportionally greatest risk with ~61,000 km(2) (~16.6% of total) lying ≤5 m elevation. In total an estimated 20.2 ± 2.5 GtC is stored in peatlands ≤5 m above sea level, which are potentially vulnerable to inundation. PMID:27354088

  11. Vulnerability of the peatland carbon sink to sea-level rise

    PubMed Central

    Whittle, Alex; Gallego-Sala, Angela V.

    2016-01-01

    Freshwater peatlands are carbon accumulating ecosystems where primary production exceeds organic matter decomposition rates in the soil, and therefore perform an important sink function in global carbon cycling. Typical peatland plant and microbial communities are adapted to the waterlogged, often acidic and low nutrient conditions that characterise them. Peatlands in coastal locations receive inputs of oceanic base cations that shift conditions from the environmental optimum of these communities altering the carbon balance. Blanket bogs are one such type of peatlands occurring in hyperoceanic regions. Using a blanket bog to coastal marsh transect in Northwest Scotland we assess the impacts of salt intrusion on carbon accumulation rates. A threshold concentration of salt input, caused by inundation, exists corresponding to rapid acidophilic to halophilic plant community change and a carbon accumulation decline. For the first time, we map areas of blanket bog vulnerable to sea-level rise, estimating that this equates to ~7.4% of the total extent and a 0.22 Tg yr−1 carbon sink. Globally, tropical peatlands face the proportionally greatest risk with ~61,000 km2 (~16.6% of total) lying ≤5 m elevation. In total an estimated 20.2 ± 2.5 GtC is stored in peatlands ≤5 m above sea level, which are potentially vulnerable to inundation. PMID:27354088

  12. Late Holocene climate-induced forest transformation and peatland establishment in the central Appalachians

    NASA Astrophysics Data System (ADS)

    Booth, Robert K.; Ireland, Alex W.; LeBoeuf, Katharine; Hessl, Amy

    2016-03-01

    Understanding the potential for ecosystem transformation and community change in response to climate variability is central to anticipating future ecological changes, and long-term records provide a primary source of information on these dynamics. We investigated the late Holocene history of upland forest and peatland development at Cranesville Swamp, a peatland located along the West Virginia-Maryland border in the USA. Our primary goal was to determine whether establishment of peatland was triggered by moisture variability, similar to recent developmental models derived from depressional peatlands in glaciated regions. Results indicate that the peatland established at about 1200 cal yr BP, and was associated with a dramatic and persistent change in upland forest composition. Furthermore, timing of these upland and wetland ecological changes corresponded with evidence for multidecadal drought and enhanced moisture variability from nearby tree-ring and speleothem climatic reconstructions. Our results add to a growing body of research highlighting the sensitivity of both peatland development and upland forest communities to transient drought and enhanced moisture variability, and suggest that enhanced moisture variability in the future could increase the probability of similarly abrupt and persistent ecological change, even in humid regions like eastern North America.

  13. Distributed hydrological modeling with channel network flow of a forestry drained peatland site

    NASA Astrophysics Data System (ADS)

    Haahti, Kersti; Warsta, Lassi; Kokkonen, Teemu; Younis, Bassam A.; Koivusalo, Harri

    2016-01-01

    Peatland drainage has been an important component of forestry management in the boreal zone and the resulting ditch networks are maintained regularly to sustain forest productivity. In Finland, this is recognized as the most detrimental forestry practice increasing diffuse loads of suspended solids. Alongside forestry management on peatlands, interest in peatland restoration has grown lately. Distributed hydrological modeling has the potential to address these matters by recognizing relevant physical mechanisms and identifying most suitable strategies for mitigating undesired outcomes. This study investigates the utility of such a modeling approach in a drained peatland forest environment. To provide a suitable tool for this purpose, we coupled channel network flow to the three-dimensional distributed hydrological model FLUSH. The resulting model was applied to a 5.2 ha drained peatland forest catchment in Eastern Finland. The model was calibrated and validated using field measurements obtained over frost-free periods of five months. The application showed that distributed modeling can disentangle the importance of spatial factors on local soil moisture conditions, which is significant as peatland drainage aims to control these conditions. In our application, we limited the spatial aspect to the topography and the drainage network, and found that the drainage configuration had a clear effect on the spatial soil moisture patterns but that the effect was less pronounced during the wetter summer. Future applications of distributed modeling in this field comprises investigating the impacts of other spatial factors, modeling channel erosion and solid transport to address strategies for their mitigation, and evaluating restoration schemes.

  14. 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.

  15. Vulnerability of the peatland carbon sink to sea-level rise

    NASA Astrophysics Data System (ADS)

    Whittle, Alex; Gallego-Sala, Angela V.

    2016-06-01

    Freshwater peatlands are carbon accumulating ecosystems where primary production exceeds organic matter decomposition rates in the soil, and therefore perform an important sink function in global carbon cycling. Typical peatland plant and microbial communities are adapted to the waterlogged, often acidic and low nutrient conditions that characterise them. Peatlands in coastal locations receive inputs of oceanic base cations that shift conditions from the environmental optimum of these communities altering the carbon balance. Blanket bogs are one such type of peatlands occurring in hyperoceanic regions. Using a blanket bog to coastal marsh transect in Northwest Scotland we assess the impacts of salt intrusion on carbon accumulation rates. A threshold concentration of salt input, caused by inundation, exists corresponding to rapid acidophilic to halophilic plant community change and a carbon accumulation decline. For the first time, we map areas of blanket bog vulnerable to sea-level rise, estimating that this equates to ~7.4% of the total extent and a 0.22 Tg yr‑1 carbon sink. Globally, tropical peatlands face the proportionally greatest risk with ~61,000 km2 (~16.6% of total) lying ≤5 m elevation. In total an estimated 20.2 ± 2.5 GtC is stored in peatlands ≤5 m above sea level, which are potentially vulnerable to inundation.

  16. Can boreal peatlands with pools be net sinks for CO2?

    NASA Astrophysics Data System (ADS)

    Pelletier, Luc; Strachan, Ian B.; Roulet, Nigel T.; Garneau, Michelle

    2015-03-01

    Peatland open-water pools, a common feature on temperate to subarctic peatlands, are sources of carbon (C) to the atmosphere but their contribution to the net ecosystem carbon dioxide exchange (NEE-CO2) is poorly known; there is a question as to whether peatlands with pools are smaller sinks of atmospheric C, or even C-neutral, compared to other peatlands. We present growing season NEE-CO2 measurements using the eddy covariance technique in a peatland with pools. We found the maximum photosynthetic uptake and ecosystem respiration rates at 10 °C to be in the lower range of the published data. The lower total vegetation biomass, due to the presence of pools, reduced CO2 uptake during day and the autotrophic component of ecosystem respiration. The low CO2 uptake combined with reduced CO2 loss resulted in the site being a net sink for CO2 of a similar magnitude as other northern peatlands despite the inclusion of pools.

  17. Did fires drive Holocene carbon sequestration in boreal ombrotrophic peatlands of eastern Canada?

    NASA Astrophysics Data System (ADS)

    van Bellen, Simon; Garneau, Michelle; Ali, Adam A.; Bergeron, Yves

    2012-07-01

    Wildfire is an important factor on carbon sequestration in the North American boreal biomes. Being globally important stocks of organic carbon, peatlands may be less sensitive to burning in comparison with upland forests, especially wet unforested ombrotrophic ecosystems as found in northeastern Canada. We aimed to determine if peatland fires have driven carbon accumulation patterns during the Holocene. To cover spatial variability, six cores from three peatlands in the Eastmain region of Quebec were analyzed for stratigraphic charcoal accumulation. Results show that regional Holocene peatland fire frequency was ~ 2.4 fires 1000 yr- 1, showing a gradually declining trend since 4000 cal yr BP, although inter- and intra-peatland variability was very high. Charcoal peak magnitudes, however, were significantly higher between 1400 and 400 cal yr BP, possibly reflecting higher charcoal production driven by differential climatic forcing aspects. Carbon accumulation rates generally declined towards the late-Holocene with minimum values of ~ 10 g m- 2 yr- 1 around 1500 cal yr BP. The absence of a clear correlation between peatland fire regimes and carbon accumulation indicates that fire regimes have not been a driving factor on carbon sequestration at the millennial time scale.

  18. Water-table-dependent hydrological changes following peatland forestry drainage and restoration: Analysis of restoration success

    NASA Astrophysics Data System (ADS)

    Menberu, Meseret Walle; Tahvanainen, Teemu; Marttila, Hannu; Irannezhad, Masoud; Ronkanen, Anna-Kaisa; Penttinen, Jouni; Kløve, Bjørn

    2016-05-01

    A before-after-control approach was used to analyze the impact of peatland restoration on hydrology, based on high temporal resolution water-table (WT) data from 43 boreal peatlands representative of a south-boreal to north-boreal climate gradient. During the study, 24 forestry drained sites were restored and 19 pristine peatlands used as control sites. Different approaches were developed and used to analyze WT changes (mean WT position, WT fluctuation, WT hydrograph, recession, and storage characteristics). Restoration increased WT in most cases but particularly in spruce mires, followed by pine mires and fens. Before restoration, the WT fluctuation (WTF) was large, indicating peat temporary storage gain (SG). After restoration, the WT hydrograph recession limb slopes and SG coefficients (Rc) declined significantly. Drainage or restoration did not significantly affect mean diurnal WT fluctuations, used here as a proxy for evapotranspiration. Overall, the changes in WT characteristics following restoration indicated creation of favorable hydrological conditions for recovery of functional peatland ecosystems in previously degraded peatland sites. This was supported by calculation of bryophyte species abundance thresholds for WT. These results can be used to optimize restoration efforts in different peatland systems and as a qualitative conceptual basis for future restoration operations.

  19. Sobol' sensitivity analysis of the Holocene Peat Model: What drives carbon accumulation in peatlands?

    NASA Astrophysics Data System (ADS)

    Quillet, Anne; Garneau, Michelle; Frolking, Steve

    2013-03-01

    Understanding the development of northern peatlands and their carbon accumulation dynamics is crucial in order to confidently integrate northern peatlands into global carbon cycle models. To achieve this, northern peatland models are becoming increasingly complex and now include feedback processes between peat depth, decomposition, hydrology, and vegetation composition and productivity. Here we present results from a global sensitivity analysis performed to assess the behavior and parameter interaction of a peatland simulation model. A series of simulations of the Holocene Peat Model were performed with different parameter combinations in order to assess the role of parameter interactions on the simulated total carbon mass after 5000 years of peatland development. The impact of parameter uncertainty on the simulation results is highlighted, as is the importance of multiple parameter interactions. The model sensitivity indicates that peat physical properties play an important role in peat accumulation; these parameters are poorly constrained by observations and should be a focus of future research. Furthermore, the results show that autogenic processes are able to produce a wide range of peatland development behaviors independently of any external environmental changes.

  20. Within-Site Variation at a Boreal Peatland Fertilization Study

    NASA Astrophysics Data System (ADS)

    Neal, E. M.; Bubier, J. L.; Moore, T.

    2001-05-01

    Due to the importance of northern peatlands as a sink for atmospheric CO2, there is concern over the possible effects of increased nutrient input in such ecosystems. Changes in CO2 fluxes caused by nutrient inputs may result in peatlands becoming a net source of atmospheric CO2 due to increased rates of decomposition. Alternatively, such fertilization of nutrient limited environments may enhance current conditions to maintain peatlands as a net sink of CO2 by increasing rates of photosynthesis or inhibiting decomposition. However, such effects may only become apparent after an extended period of increased nutrient loading. Net Ecosystem Exchange (NEE) of atmospheric CO2 was measured over the course of the growing season (May-August 2000) at Mer Bleue, a raised, ombrotrophic bog in Ontario, Canada using a LI-COR 6200 infrared gas analyzer and climate-controlled chambers. Dominant plant communities were composed of Sphagnum species and ericaceous shrubs. The site was treated every three weeks with varying levels of Nitrogen (N) and Phosphorous (P). Treatments were based on the ecosystem's ambient nutrient load of approximately 0.26 g N/m2/year of NH4 and 0.40 g N/m2/year of NO3 due to wet atmospheric deposition. Collars were grouped into triplicates according to treatment levels: distilled water, PK (no N), 5 times ambient N, 5 times ambient N plus PK, 10 times ambient N plus PK, and 20 times ambient N plus PK. NEE ranged from -4.88 to 5.12 μ mol CO2/m2 in the control collars and from -7.99 to 7.66 μ mol CO2/m2 in the nutrient addition collars. Preliminary data analysis indicates that although there has been a slight response from the nutrient additions, subtle differences in micro topography at the fertilization site (which creates slight variation in water table and temperature) have had a stronger initial effect on NEE. When collars are compared according to treatment triplicates, the effects of water table and temperature have the strongest effect on NEE. In

  1. Peatland restoration and effects on groundwater, water quality and runoff

    NASA Astrophysics Data System (ADS)

    Menberu, Meseret; Tahvanainen, Teemu; Irannezhad, Masoud; Ronkanen, Anna-Kaisa; Marttila, Hannu; Penttinen, Jouni; Klöve, Björn

    2015-04-01

    There is increasing interest to restore degraded peatland, but long term effects of restoration are poorly known. Totally 46 boreal peatland were included in a study set, including 20 fens, 13 pine mires and 13 spruce mires, with peatland types ranging from nearly ombrotrophic Sphagnum bogs to rich fens. Study sites covered spatially almost whole Finland. Furthermore, 27 of the sites were previously drained and restored during the monitoring period, while the remaining 19 sites were in pristine condition. The pristine sites were held as paired counterparts of the drained sites and are located in the vicinity of drained/restored sites to ensure similar vegetation, nutrient and hydrological status. Since 2008, water table fluctuation (continuous measurement), pore water chemistry at all sites, and runoff and water chemistry (nutrients, DOC, ions with adjusted intervals through frost-free season) from 9 sites were studied. Drained/restored sites were monitored for 1 to 3 years before restoration. This presentation shows preliminary results and analysis of present dataset. Restoration operation increased water table (WT) in all study areas, but high variation was observed. Highest change in WT elevation was observed in spruce mires and smaller increases in fens. Disturbance of peat material and higher WT caused leaching of nutrients and ions from restoration areas, e.g. phosphorus, nitrogen and iron. Increase was highest during the first year after restoration, but showed decreasing trend almost in all study areas in pore-water samples. Generally it can be concluded that restoration have reached its main target for elevated WT, launching re-development of acrotelm peat layers. However, restoration operation caused disturbance and elevated nutrient loading to water courses. Preliminary results of statistical analysis revealed no significant differences of mean daily runoff between drained and pristine counterparts. After restoration, one study site showed decrease in

  2. Significant Alaska minerals

    SciTech Connect

    Robinson, M.S.; Bundtzen, T.K.

    1982-01-01

    Alaska ranks in the top four states in gold production. About 30.5 million troy oz have been produced from lode and placer deposits. Until 1930, Alaska was among the top 10 states in copper production; in 1981, Kennecott Copper Company had prospects of metal worth at least $7 billion. More than 85% of the 20 million oz of silver derived have been byproducts of copper mining. Nearly all lead production has been as a byproduct of gold milling. Molybdenum is a future Alaskan product; in 1987 production is scheduled to be about 12% of world demand. Uranium deposits discovered in the Southeast are small but of high grade and easily accessible; farther exploration depends on improvement of a depressed market. Little has been done with Alaskan iron and zinc, although large deposits of the latter were discovered. Alaskan jade has a market among craftspeople. A map of the mining districts is included. 2 figures, 1 table.

  3. Coal resources of Alaska

    SciTech Connect

    Sanders, R.B.

    1982-01-01

    In the late 1800s, whaling ships carried Alaskan coal, and it was used to thaw ground for placer gold mining. Unfortunate and costly political maneuvers in the early 1900s delayed coal removal, but the Alaska Railroad and then World War II provided incentives for opening mines. Today, 33 million acres (about 9% of the state) is classified as prospectively valuable for coal, much of it under federal title. Although the state's geology is poorly known, potential for discovery of new fields exists. The US Geological Survey estimates are outdated, although still officially used. The total Alaska onshore coal resource is estimated to be 216 to 4216 billion tons of which 141 billion tons are identified resources; an additional 1430 billion tons are believed to lie beneath Cook Inlet. Transportation over mountain ranges and wetlands is the biggest hurdle for removal. Known coal sources and types are described and mapped. 1 figure.

  4. A Special Report on the Alaska Commission on Postsecondary Education--Collection of Defaulted Student Loans.

    ERIC Educational Resources Information Center

    Welker, Randy S.

    In accordance with a Legislative Budget and Audit Committee special request and the provisions of Title 24 of the Alaska Statutes, a review was conducted of the Alaska Commission on Postsecondary Education's experience with various collection contractors used to collect defaulted student loans. The primary purpose was to assess the success that…

  5. It's Okay To Be Native: Alaska Native Cultural Strategies in Urban and School Settings.

    ERIC Educational Resources Information Center

    Grantham-Campbell, Mary

    1998-01-01

    The urban Alaska Native community in and around Fairbanks is drawing on its rural roots to reshape schooling experiences. Alaska Natives are resisting the pattern of dropping out and are claiming a place in school, asserting that it's okay to be Native; Native teachers are committed to developing Native curricular materials; and tribal colleges…

  6. Engaging Elements of Cancer-Related Digital Stories in Alaska.

    PubMed

    Cueva, Melany; Kuhnley, Regina; Revels, Laura; Schoenberg, Nancy E; Lanier, Anne; Dignan, Mark

    2016-09-01

    The tradition of storytelling is an integral part of Alaska Native cultures that continues to be a way of passing on knowledge. Using a story-based approach to share cancer education is grounded in Alaska Native traditions and people's experiences and has the potential to positively impact cancer knowledge, understandings, and wellness choices. Community health workers (CHWs) in Alaska created a personal digital story as part of a 5-day, in-person cancer education course. To identify engaging elements of digital stories among Alaska Native people, one focus group was held in each of three different Alaska communities with a total of 29 adult participants. After viewing CHWs' digital stories created during CHW cancer education courses, focus group participants commented verbally and in writing about cultural relevance, engaging elements, information learned, and intent to change health behavior. Digital stories were described by Alaska focus group participants as being culturally respectful, informational, inspiring, and motivational. Viewers shared that they liked digital stories because they were short (only 2-3 min); nondirective and not preachy; emotional, told as a personal story and not just facts and figures; and relevant, using photos that showed Alaskan places and people. PMID:25865400

  7. Aniakchak Crater, Alaska Peninsula

    USGS Publications Warehouse

    Smith, Walter R.

    1925-01-01

    The discovery of a gigantic crater northwest of Aniakchak Bay (see fig. 11) closes what had been thought to be a wide gap in the extensive series of volcanoes occurring at irregular intervals for nearly 600 miles along the axial line of the Alaska Peninsula and the Aleutian Islands. In this belt there are more active and recently active volcanoes than in all the rest of North America. Exclusive of those on the west side of Cook Inlet, which, however, belong to the same group, this belt contains at least 42 active or well-preserved volcanoes and about half as many mountains suspected or reported to be volcanoes. The locations of some of these mountains and the hot springs on the Alaska Peninsula and the Aleutian Islands are shown on a map prepared by G. A. Waring. Attention has been called to these volcanoes for nearly two centuries, but a record of their activity since the discovery of Alaska is far from being complete, and an adequate description of them as a group has never been written. Owing to their recent activity or unusual scenic beauty, some of the best known of the group are Mounts Katmai, Bogoslof, and Shishaldin, but there are many other beautiful and interesting cones and craters.

  8. The compost bomb: thermal instability in peatland soils

    NASA Astrophysics Data System (ADS)

    Luke, C. M.; Cox, P. M.

    2009-04-01

    A simple model is constructed to investigate the effect of thermal energy generated by microbial respiration on soil temperature and soil carbon stocks, specifically in peat soils. Stability analysis shows a potential tipping point in the system beyond which a sudden large increase in soil temperature and decrease in soil carbon is predicted. Stability of the system depends on a dimensionless number, itself dependent on the effective soil thermal conductivity and the temperature sensitivity of microbial respiration. The influence of soil moisture on the effective thermal conductivity, and therefore the stability of the system, is also investigated. These results suggest that peatland soils insulated by a moss or lichen layer are potentially destabilised under certain conditions of warming and drying.

  9. Ammonium release from a blanket peatland into headwater stream systems.

    PubMed

    Daniels, S M; Evans, M G; Agnew, C T; Allott, T E H

    2012-04-01

    Hydrochemical sampling of South Pennine (UK) headwater streams draining eroded upland peatlands demonstrates these systems are nitrogen saturated, with significant leaching of dissolved inorganic nitrogen (DIN), particularly ammonium, during both stormflow and baseflow conditions. DIN leaching at sub-catchment scale is controlled by geomorphological context; in catchments with low gully densities ammonium leaching dominates whereas highly gullied catchments leach ammonium and nitrate since lower water tables and increased aeration encourages nitrification. Stormflow flux calculations indicate that: approximately equivalent amounts of nitrate are deposited and exported; ammonium export significantly exceeds atmospheric inputs. This suggests two ammonium sources: high atmospheric loadings; and mineralisation of organic nitrogen stored in peat. Downstream trends indicate rapid transformation of leached ammonium into nitrate. It is important that low-order headwater streams are adequately considered when assessing impacts of atmospheric loads on the hydrochemistry of stream networks, especially with respect to erosion, climate change and reduced precipitation. PMID:22285801

  10. Long-term macronutrient stoichiometry of UK ombrotrophic peatlands

    NASA Astrophysics Data System (ADS)

    Schillereff, Daniel; Boyle, John; Toberman, Hannah; Adams, Jessica; Tipping, Ed

    2016-04-01

    Ombrotrophic peatlands across northern latitudes represent a globally-important store for carbon (C), nitrogen (N) and phosphorus (P) through the Holocene. A key characteristic of ombrotrophic bogs is that N, P and other elements vital to their biogeochemical functioning are almost exclusively supplied by hydrological and biological inputs from the atmosphere. While different mechanisms regulating the atmospheric supply of N and P and their limiting effects on bog productivity have been widely studied, limited attention has been paid to the long-term patterns of, and controls on, macronutrient accumulation, cycling and stoichiometry in ombrotrophic peatlands. Indeed there is a dearth of C, N and P stoichiometric data from the UK despite decades of peatland research. Using data from 15 sites, we report the first estimates of millennial-scale macronutrient concentrations and accumulation rates in UK ombrotrophic peats. Carbon, nitrogen and phosphorus concentrations were measured on cores from five ombrotrophic blanket mires, spanning 4000-10000 years to present, and integrated with existing nutrient profiles from ten Scottish sites. Long-term C, N and P concentrations for the UK are 55.1, 1.55 and 0.037 wt%, similar to the few existing northern and tropical comparable sites worldwide. The uppermost peat (0 - 0.2 m) is more enriched in P and N (51.0, 1.86, and 0.070 wt%), while the deeper peat (0.5 - 1.25 m) is more depleted (56.6, 1.39, and 0.028 wt%). Long-term average (whole core) accumulation rates of carbon, nitrogen and phosphorus are 25.3±2.2 gC m‑2 yr‑1, 0.70±0.09 gN m‑2 yr‑1 and 0.018±0.004 gP m‑2 yr‑1, again similar to values reported elsewhere in the world. A number of significant findings can be drawn from our results: i) N and P concentrations in ombrotrophic peat are strongly associated, such that a regression model of N concentration on P concentration and mean annual precipitation, based on global meta data for surface peat samples, can

  11. Monitoring Peatland ecosystem dynamics using multisensor satellite data

    NASA Astrophysics Data System (ADS)

    Romshoo, S.; Shimada, M.; Igarashi, T.; Rosenqvist, A.

    Peatlands are multi-functional natural systems, which perform many globally, regionally, and locally important natural resource functions. They are key links in the cycles of water, carbon and other chemical elements and substances, supporting biological diversity, and accumulating energy, matter and information. Their total carbon pool exceeds that of the world's forests and equals that of the atmosphere. They are complex systems with a specific environm nt in which they exist ande function. The range and importance of the diverse functions, services and resources provided by peatlands are changing with increases in human demand and development of new technologies. These functions can have different values on different spatial (local, regional, national, international, etc.) and temporal (short- term and long-term) levels that may lead to intersectoral conflicts and problems for co-ordinating wise management of peatlands. Keeping in view their ecological and economic importance in the Southeast Asian region, an integrated study was conducted, employing JERS-1 SAR and optical data, to find out how the SAR data could be used to understand the complex ecological processes of these ecosystems. As a first step, it was found out that large tracts of these peatlands have been lost as a result of being diverted to other unproductive land uses from 1994 to 1998 and the process is going on unabated. Such a reckless destruction of these carbon rich forests have resulted in the release of huge amount of carbon to the atmosphere as confirmed from the flux measurements in the area. In order to better understand and quantify the cycles of carbon and water in these ecosystem using bio-geophysical models, it is important to characterize the vegetation and seasonal patterns of the inundation. Both, a single scene and a time series of L-band SAR data were used for the land surface characterization. The vegetation characterization was markedly improved with the use of a time series

  12. Linkage among Vegetation, Microbes and Methanogenic Pathways in Alaskan Peatlands

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Sidelinger, W.; Shu, H.; Varner, R. K.; Hines, M. E.

    2014-12-01

    Northern wetlands are thought to account for one third of the naturally emitted CH4. However, methane production pathways in northern peatlands are poorly understood, yet are predicted to change in response to vegetation shifts due to warming. Previous studies noted that acetate conversion to methane (acetoclastic methanogenesis, AM) in northern wetlands is largely impeded and acetate accumulates, however AM tends to increase with minerotrophy. To understand methanogenic pathways and to provide linkage among pathways, we studied Alaskan wetlands in 2013 and 2014. In 2013, laboratory incubations were conducted in three peatlands representing trophic gradients from bogs to fens. During 2014, 37 different sites in Fairbanks and Anchorage were studied that represented wetlands with pH values from 3.5 to 5.5 and vegetation from primarily Sphagnum to sedges. Measurements in 2014 included vegetation composition, gases (CH4, CO2, H2, and CO), 13CH4 and 13CO2, volatile fatty acids, DOC, other electron acceptors. Further incubation studies are being conducted to decipher controls on decomposition pathways. Gene sequencing was used to characterize microbial community composition, and metagenomic and transcriptomics were conducted to describe community activity. Results showed that methanogenesis was higher in fens than bogs, but hydrogenotrophic methanogenesis (HM) was dominant at all sites. End product ratios showed that AM was occurring in fens, albeit slowly. Fermentation was an important end-point in decomposition and microbial syntrophy was weak. These data, regardless of trophic status, differed greatly from data obtained from temperate wetlands in which terminal respiratory processes were strong and C flow through syntrophy was important. Trophic status influenced C flow in the Alaskan sites, but terminal processes were weak and end product formation tended to end at primary fermentation, which dominated as the terminal step in decomposition.

  13. Predicting methane emission from bryophyte distribution in northern Canadian peatlands

    SciTech Connect

    Bubier, J.L.; Moore, T.R.; Juggins, S.

    1995-04-01

    A predictive model for bryophyte distribution, water table position, and seasonal mean methane (CH{sub 4}) emission was developed for two areas of northern peatland: the Clay Belt of Ontario and the Labrador Trough of Quebec. Water table position and CH{sub 4} flux were the most important environmental variables in canonical correspondence analyses (CCA) of bryophyte data. Water chemistry constituted a second environmental gradient, independent of hydrology and CH{sub 4} flux. Weighted averaging regression and calibration were used to develop a model for predicting log CH{sub 4} flux from bryophyte distribution. The model showed an increase in log CH{sub 4} flux from hummock to carpet and pool species, corresponding with a decrease in height above the mean water table position. The exceptions were rich-fen pool species, which had low CH{sub 4} flux optima in spite of their moisture status. Tolerances were greatest for mid-hummock species and least for carpet and pool species. No overlap in tolerances occurred between hummock and pool species, suggesting that at either end of the height gradient are the best predictors of CH{sub 4} flux. Error analyses showed that bryophytes are equally as effective as water table position for predicting mean CH{sub 4} flux. Bryophytes are distributed in well-defined zones along microtopographic gradients: they integrate long-term changes in the water table, which fluctuates on a daily and seasonal basis along with CH{sub 4} flux, and may be more easily mapped with remote-sensing techniques. Bryophytes, however, are only useful for predicting CH{sub 4} flux within a region; similar species values cannot be extrapolated to other northern peatlands where different climatic and biogeochemical factors may exist. The model may be used in paleoreconstructions of methane emission and for biological monitoring of climate change. 62 refs., 8 figs., 3 tabs.

  14. Methane emission modeling with MCMC calibration for a boreal peatland

    NASA Astrophysics Data System (ADS)

    Raivonen, Maarit; Smolander, Sampo; Susiluoto, Jouni; Backman, Leif; Li, Xuefei; Markkanen, Tiina; Kleinen, Thomas; Makela, Jarmo; Aalto, Tuula; Rinne, Janne; Brovkin, Victor; Vesala, Timo

    2016-04-01

    Natural wetlands, particularly peatlands of the boreal latitudes, are a significant source of methane (CH4). At the moment, the emission estimates are highly uncertain. These natural emissions respond to climatic variability, so it is necessary to understand their dynamics, in order to be able to predict how they affect the greenhouse gas balance in the future. We have developed a model of CH4 production, oxidation and transport in boreal peatlands. It simulates production of CH4 as a proportion of anaerobic peat respiration, transport of CH4 and oxygen between the soil and the atmosphere via diffusion in aerenchymatous plants and in peat pores (water and air filled), ebullition and oxidation of CH4 by methanotrophic microbes. Ultimately, we aim to add the model functionality to global climate models such as the JSBACH (Reick et al., 2013), the land surface scheme of the MPI Earth System Model. We tested the model with measured methane fluxes (using eddy covariance technique) from the Siikaneva site, an oligotrophic boreal fen in southern Finland (61°49' N, 24°11' E), over years 2005-2011. To give the model estimates regional reliability, we calibrated the model using Markov chain Monte Carlo (MCMC) technique. Although the simulations and the research are still ongoing, preliminary results from the MCMC calibration can be described as very promising considering that the model is still at relatively early stage. We will present the model and its dynamics as well as results from the MCMC calibration and the comparison with Siikaneva flux data.

  15. Variable carbon losses from recurrent fires in drained tropical peatlands.

    PubMed

    Konecny, Kristina; Ballhorn, Uwe; Navratil, Peter; Jubanski, Juilson; Page, Susan E; Tansey, Kevin; Hooijer, Aljosja; Vernimmen, Ronald; Siegert, Florian

    2016-04-01

    Tropical peatland fires play a significant role in the context of global warming through emissions of substantial amounts of greenhouse gases. However, the state of knowledge on carbon loss from these fires is still poorly developed with few studies reporting the associated mass of peat consumed. Furthermore, spatial and temporal variations in burn depth have not been previously quantified. This study presents the first spatially explicit investigation of fire-driven tropical peat loss and its variability. An extensive airborne Light Detection and Ranging data set was used to develop a prefire peat surface modelling methodology, enabling the spatially differentiated quantification of burned area depth over the entire burned area. We observe a strong interdependence between burned area depth, fire frequency and distance to drainage canals. For the first time, we show that relative burned area depth decreases over the first four fire events and is constant thereafter. Based on our results, we revise existing peat and carbon loss estimates for recurrent fires in drained tropical peatlands. We suggest values for the dry mass of peat fuel consumed that are 206 t ha(-1) for initial fires, reducing to 115 t ha(-1) for second, 69 t ha(-1) for third and 23 t ha(-1) for successive fires, which are 58-7% of the current IPCC Tier 1 default value for all fires. In our study area, this results in carbon losses of 114, 64, 38 and 13 t C ha(-1) for first to fourth fires, respectively. Furthermore, we show that with increasing proximity to drainage canals both burned area depth and the probability of recurrent fires increase and present equations explaining burned area depth as a function of distance to drainage canal. This improved knowledge enables a more accurate approach to emissions accounting and will support IPCC Tier 2 reporting of fire emissions. PMID:26661597

  16. The Carbon Stocks of Peatlands Under Forestry in the Republic of Ireland.

    NASA Astrophysics Data System (ADS)

    Wellock, M.; Laperle, C.; Kiely, G.; Reidy, B.; Duffy, C.; Tobin, B.

    2009-04-01

    Under the Kyoto Protocol it is necessary for all industries (including forestry) within the Republic of Ireland to report their GHG emission sinks and sources. Forestry plays an important role within the global carbon cycle as a carbon store within the biomass (above- and below-ground), litter and soil. Along with forests, peatlands are another important store for carbon, holding around one third of the global soil carbon pool. Peatlands held very important roles for irish society for hundreds of years, i.e. agriculture, horticulture, energy etc, and cover approximately 17.2 % or 1.34 million ha of the total irish land area (Hammond, 1981) with around 260,000 ha of the peatland forested (NFI, 2007). Afforestation of peatlands began in Ireland in the 1950s with the majority of the planting being done by the state. At present the state doesn't forest peatland, but there is still substantial planting from the private sector. Afforested peatland in Ireland represents a large store of C and so far there has been no quantification of the total carbon stock of the soil. The project FORESTC is aiming to provide an analysis of the stocks of C that are stored within the afforested peatlands of Ireland. To achieve this 20 forested peatland sites around Ireland will be sampled, comprising 5 conifer, low level blanket peat sites (peats located at elevations lower than 150 m), 5 conifer, high level blanket peat sites (peats located at elevations greater than 150 m), 5 conifer basin peats and 5 mixed conifer and broadleaf basin peats. The peat will be sampled down the entire soil profile up to 10 m deep for both bulk density and carbon % every 50 cm using a peat sampler (Eijlelkamp, NL). Along with the peat samples, litter and F/H layer samples will be taken to quantify the carbon stock of the litter layer atop the peat. This data shall then be able to provide a total carbon stock of these 20 forest sites that hopefully will allow for the estimation of the total C stock of the

  17. The role of lichen on peatland development in the Hudson Bay Lowlands, Canada

    NASA Astrophysics Data System (ADS)

    Harris, Lorna; Moore, Tim; Roulet, Nigel

    2015-04-01

    Lichen (Cladina stellaris) can be a dominant vegetation cover on bogs within the extensive peatland landscape of the Hudson Bay Lowlands (HBL), northern Ontario, Canada. The unique characteristics of lichens (growth structure and function as a symbiotic organism), their ability to form thick, dense mats across the HBL bogs, and their increased tolerance of extreme environmental conditions, points to their importance as a distinct plant functional type. However, the role of lichen within the peatland ecosystem is poorly understood, particularly ecosystem interactions (vegetation associations) and peatland development (including microtopography) and the resulting carbon sink. Many studies consider the role of different plant functional types on peatland CO2 and CH4 exchange (e.g. Bubier et al., 2003; Strack et al., 2006), and this understanding is included in peatland growth and climate change models. As far as we are aware lichens are currently omitted from these models. We suggest that lichens represent a distinct plant functional type with CO2 exchange characteristics (NEE and respiration) that are quite different to vascular plants and mosses. In this study we measured lichen CO2 exchange in both natural and modified moisture conditions at field sites in the HBL over two field seasons. Our results indicate that lichen productivity is strongly influenced by abiotic factors that affect lichen moisture content, with very dry lichen exhibiting little or no photosynthetic capacity. We suggest that the low productivity of lichen mats results in lower rates of peat accumulation compared to Sphagnum-dominated peatland areas, and that this has consequences for the development of peatland microtopography (hummocks and hollows) and feedback mechanisms. To better understand the role of lichen mats on peat accumulation and to test possible feedback mechanisms we developed a model, the parameters of which are supported by data from field sites in the HBL. This dependence of

  18. Stable isotopes of water in estimation of groundwater dependence in peatlands

    NASA Astrophysics Data System (ADS)

    Isokangas, Elina; Rossi, Pekka; Ronkanen, Anna-Kaisa; Marttila, Hannu; Rozanski, Kazimierz; Kløve, Bjørn

    2016-04-01

    Peatland hydrology and ecology can be irreversibly affected by anthropogenic actions or climate change. Especially sensitive are groundwater dependent areas which are difficult to determine. Environmental tracers such as stable isotopes of water are efficient tools to identify these dependent areas and study water flow patterns in peatlands. In this study the groundwater dependence of a Finnish peatland complex situated next to an esker aquifer was studied. Groundwater seepage areas in the peatland were localized by thermal imaging and the subsoil structure was determined using ground penetrating radar. Water samples were collected for stable isotopes of water (δ18O and δ2H), temperature, pH and electrical conductivity at 133 locations of the studied peatland (depth of 10 cm) at approximately 100 m intervals during 4 August - 11 August 2014. In addition, 10 vertical profiles were sampled (10, 30, 60 and 90 cm depth) for the same parameters and for hydraulic conductivity. The cavity ring-down spectroscopy (CRDS) was applied to measure δ18O and δ2H values. The local meteoric water line was determined using precipitation samples from Nuoritta station located 17 km west of the study area and the local evaporation line was defined using water samples from lake Sarvilampi situated on the studied peatland complex. Both near-surface spatial survey and depth profiles of peatland water revealed very wide range in stable isotope composition, from approximately -13.0 to -6.0 ‰ for δ18O and from -94 to -49 ‰ for δ2H, pointing to spatially varying influence of groundwater input from near-by esker aquifer. In addition, position of the data points with respect to the local meteoric water line showed spatially varying degree of evaporation of peatland water. Stable isotope signatures of peatland water in combination with thermal images delineated the specific groundwater dependent areas. By combining the information gained from different types of observations, the

  19. Alaska's Children, 2000. Alaska Head Start State Collaboration Project. Quarterly Report.

    ERIC Educational Resources Information Center

    Douglas, Dorothy, Ed.

    2000-01-01

    This document consists of the two 2000 issues of "Alaska's Children," which provides information on the Alaska Head Start State Collaboration Project and updates on Head Start activities in Alaska. Regular features include a calendar of conferences and meetings, a status report on Alaska's children, reports from the Alaska Children's Trust, and…

  20. 78 FR 53137 - Flint Hills Resources Alaska, LLC, BP Pipelines (Alaska) Inc., ConocoPhillips Transportation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-28

    ... formal complaint against BP Pipelines (Alaska) Inc., ConocoPhillips Transportation Alaska, Inc., and... Energy Regulatory Commission Flint Hills Resources Alaska, LLC, BP Pipelines (Alaska) Inc., ConocoPhillips Transportation Alaska, Inc., ExxonMobil Pipeline Company; Notice of Complaint Take notice that...

  1. Rural Alaska Mentoring Project (RAMP)

    ERIC Educational Resources Information Center

    Cash, Terry

    2011-01-01

    For over two years the National Dropout Prevention Center (NDPC) at Clemson University has been supporting the Lower Kuskokwim School District (LKSD) in NW Alaska with their efforts to reduce high school dropout in 23 remote Yup'ik Eskimo villages. The Rural Alaska Mentoring Project (RAMP) provides school-based E-mentoring services to 164…

  2. Alaska Native Land Claims. [Textbook].

    ERIC Educational Resources Information Center

    Arnold, Robert D.; And Others

    Written for students at the secondary level, this textbook on Alaska Native land claims includes nine chapters, eight appendices, photographs, maps, graphs, bibliography, and an index. Chapters are titled as follows: (1) Earliest Times (Alaska's first settlers, eighteenth century territories, and other claimants); (2) American Indians and Their…

  3. Preparing Teachers for Rural Alaska.

    ERIC Educational Resources Information Center

    Barnhardt, Ray

    1999-01-01

    This article discusses preparing teachers to teach in rural Alaska. An anecdote illustrates how outsiders who come to work in rural Alaska get into trouble because they are unprepared for conditions unique to the North. These conditions end up being viewed as impediments rather than opportunities. The same is true for the field of education. Of…

  4. Can Decommissioned Oil Pads in Boreal Alberta BE Reclaimed to Carbon Accumulating Peatlands?

    NASA Astrophysics Data System (ADS)

    Wieder, R.; Vitt, D. H.; Mowbray, S.

    2010-12-01

    In northern Alberta where peatland ecosystems are a dominant landscape feature, construction of oil drilling pads and access roads is a major disturbance. Reclamation of decommissioned oil pads has been hampered by the lack of research. At two decommissioned oil pads at Shell Oil’s Peace River Complex (northeastern Alberta), initially constructed in a bog/fen complex, we established a field experiment to assess reclamation approaches that could lead to a system reflecting undisturbed peatland structure (vegetation composition) and function (net carbon accumulation). In the fall of 2007, mineral soil was removed from two decommissioned pads in areas approximately 100-m x 30-m creating a mineral surface at or near the surrounding bog water table level. We established the following treatments: pad (fertilized vs. unfertilized); water table position (at and 5-cm above the surrounding bog water level); texture (tilling soil amendments into the mineral soil or not); amendment (controls; commercial peat, peat that had been stockpiled in a farmer’s field; landscape fabric; slough hay (native species hay from harvested from local farms), aspen wood chips); planting (in 1-m x 1-m subplots within 2-m x 2-m amendment plots: no planting, 9 Carex aquatilis plants, 5 C. aquatilis and 4 Salix lutea plants; 3 C. aquatilis, 3 S. lutea and 3 Larix laricina seedlings). Treatments were nested (planting within amendment, within texture, within water table level, within pad), with 6 replicate 2-m x 2-m plots of each amendment within each pad x texture x water level combination. Net CO2 exchange was quantified under a range of PAR conditions from full sunlight to complete darkness in each 1-m x 1-m planting subplot repeatedly during the summers of 2008, 2009 and 2010 using closed chambers and infrared gas analyzers. Both dark respiration and maximum net ecosystem production (NEPSAT; net CO2 sequestration when PAR>1000 μmol m-2 s-1) exhibited year x planting interactions (p<0.0001 and

  5. Tracing peatland geomorphology: sediment and contaminant movements in eroding and restored systems

    NASA Astrophysics Data System (ADS)

    Shuttleworth, Emma; Evans, Martin; Hutchinson, Simon; Rothwell, James

    2015-04-01

    Peatlands are an important store of soil carbon, play a vital role in global carbon cycling, and can also act as sinks of atmospherically deposited heavy metals. However, large areas of blanket peat are significantly degraded and actively eroding as a direct result of anthropogenic pressures, which negatively impacts carbon and pollutant storage. The restoration of eroding UK peatlands is a major conservation concern, and over the last decade measures have been taken to control erosion and restore large areas of degraded peat. In severely eroded peatlands, topography is highly variable, and an appreciation of geomorphological form and process is key in understanding the controls on peatland function, and in mitigating the negative impacts of peatland erosion. The blanket peats of the Peak District, Southern Pennines, UK embody many problems and pressures faced by peatlands globally, and are amongst the most heavily eroded and contaminated in the world. The near-surface layer of the peat is contaminated by high concentrations of anthropogenically derived, atmospherically deposited heavy metals which are released into the fluvial system as a consequence of widespread erosion. Whilst not desirable, this legacy of lead pollution and its release offer a unique opportunity to trace peatland sediment movements and thus investigate the controls on sediment and contaminant mobility. A suite of established field, analytical and modelling techniques have been modified and adapted for use in peatland environments and these have been successfully employed in combination to address issues of sediment and contaminant release at a range of scales, including: (i) the development of field portable XRF to assess in situ lead concentrations in wet organic sediments; (ii) adaptation of time integrated mass flux samplers to explore spatial and temporal sediment dynamics in peatland streams; and (iii) the application of sediment source fingerprinting and numerical mixing models to

  6. Climate change impacts on stream carbon export from coastal temperate rainforest ecosystems in Alaska (Invited)

    NASA Astrophysics Data System (ADS)

    Hood, E. W.

    2013-12-01

    Coastal temperate rainforests (CTR) in Alaska contain about 10% of the total carbon in the forests of the conterminous United States. CTR ecosystems span a large environmental gradient that ranges from icefields mantling the Coast Mountains to carbon-rich conifer forests along the coastal margin and within the islands of the Alexander Archipelago in the Gulf of Alaska. Riverine dissolved organic carbon (DOC) export from Alaskan CTR ecosystems, which can exceed 2 Tg C yr-1, is large relative to other northern ecosystems as a result of high rates of specific discharge (~2.5 m yr-1) and an abundance of organic soils found in peatlands and forested wetlands. Runoff from glaciers, which are rapidly thinning and retreating, has also been shown to an important contributor to land-to-ocean fluxes of DOC in this region. Downscaled regional climate models suggest that CTR ecosystems in Alaska will become warmer and wetter in coming decades, with uncertain effects on riverine organic matter (OM) export. Changes in watershed OM export are likely to be driven by changes in both hydrology and the availability of OM in terrestrial source pools. However, the impacts of these climate driven changes will vary with watershed landcover across the continuum from icefields to coastal temperate forests. Expected hydrological perturbations include changes in the timing and magnitude of streamflow associated with shifts in: 1) the extent and duration of seasonal snowcover and 2) the mass balance of glaciers and icefields in the Coast Mountains. The availability of OM for export along hydrologic flowpaths will likely be altered by increased soil temperatures and shifts in water table elevations during the summer/fall runoff season. This will be particularly true for organic carbon export from peatlands in which changes in temperature and oxygen availability can strongly impact rates of organic matter decomposition. This talk will explore how climate-driven changes in hydrology and

  7. GeoFORCE Alaska, A Successful Summer Exploring Alaska's Geology

    NASA Astrophysics Data System (ADS)

    Wartes, D.

    2012-12-01

    Thirty years old this summer, RAHI, the Rural Alaska Honors Institute is a statewide, six-week, summer college-preparatory bridge program at the University of Alaska Fairbanks for Alaska Native and rural high school juniors and seniors. This summer, in collaboration with the University of Texas Austin, the Rural Alaska Honors Institute launched a new program, GeoFORCE Alaska. This outreach initiative is designed to increase the number and diversity of students pursuing STEM degree programs and entering the future high-tech workforce. It uses Earth science to entice kids to get excited about dinosaurs, volcanoes and earthquakes, and includes physics, chemistry, math, biology and other sciences. Students were recruited from the Alaska's Arctic North Slope schools, in 8th grade to begin the annual program of approximately 8 days, the summer before their 9th grade year and then remain in the program for all four years of high school. They must maintain a B or better grade average and participate in all GeoFORCE events. The culmination is an exciting field event each summer. Over the four-year period, events will include trips to Fairbanks and Anchorage, Arizona, Oregon and the Appalachians. All trips focus on Earth science and include a 100+ page guidebook, with tests every night culminating with a final exam. GeoFORCE Alaska was begun by the University of Alaska Fairbanks in partnership with the University of Texas at Austin, which has had tremendous success with GeoFORCE Texas. GeoFORCE Alaska is managed by UAF's long-standing Rural Alaska Honors Institute, that has been successfully providing intense STEM educational opportunities for Alaskan high school students for over 30 years. The program will add a new cohort of 9th graders each year for the next four years. By the summer of 2015, GeoFORCE Alaska is targeting a capacity of 160 students in grades 9th through 12th. Join us to find out more about this exciting new initiative, which is enticing young Alaska Native

  8. 2013 Alaska Performance Scholarship Outcomes Report

    ERIC Educational Resources Information Center

    Rae, Brian

    2013-01-01

    In accordance with Alaska statute the departments of Education & Early Development (EED) and Labor and Workforce Development (DOLWD), the University of Alaska (UA), and the Alaska Commission on Postsecondary Education (ACPE) present this second annual report on the Alaska Performance Scholarship (APS). Among the highlights: (1) In the public…

  9. Importance of West Siberian Peatlands to Global Carbon and Water Cycles

    NASA Astrophysics Data System (ADS)

    Smith, L. C.

    2014-12-01

    Russia's West Siberian Lowland (WSL) contains nearly 600,000 km2 of peatlands with depth >0.5 m, the most extensive such deposits in the world. These peatlands impact the global carbon cycle, representing an important CH4 source and net CO2 sink since the early Holocene. However, together with other Arctic and sub-Arctic peatlands, the likely responses of WSL peatlands to warming climate and associated permafrost degradation are a subject of ongoing study and debate. Of prime interest is whether WSL peatlands may switch from a net carbon sink to source, especially in permafrost peatlands. Climate models predict warmer temperatures, longer growing seasons, and enhanced precipitation which should increase net primary productivity and litter production, but also soil microbial decomposition, increasing release of sequestered carbon through outgassing of CH4 and/or CO2 to the atmosphere. Projecting the net outcome of these opposing ecosystem processes on carbon sink/source status requires is difficult, and given strong N-S temperature and permafrost gradients across the WSL, the response will likely vary geographically. Hydrological status is deeply important because aerobic dry peats emit a greater fraction of CO2 whereas anaerobic wet peats predominately release CH4. A first estimate of subsurface water storage in WSL peatlands suggests they may hold ~1,200 km3 of liquid-water equivalent (~2 m), a large number that is roughly triple the annual flow of water in the Ob' River. New models, observations, and synthesis are needed to confidently project the future role of this important region to global carbon and water cycles.

  10. 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.

  11. Carbon stored in peatlands formed by terrestrialization: the importance of buried lake sediments

    NASA Astrophysics Data System (ADS)

    Talbot, J.

    2015-12-01

    A lot of efforts have been made over the last few decades to quantify the amount of carbon stored in soils, including in peat-producing systems. Estimates of soil carbon storage at the landscape scale has to take into account all buried carbon pools, including deep-buried lake sediments found under many peatlands that formed by terrestrialization. To illustrate the importance of buried lake sediments in the overall carbon storage of a peatland site, we studied a small peat swamp located in Gatineau Park (Quebec, Canada), the Folly peatland (45°27'18.12"N 75°46'57.38''W). This 7 ha peatland developed from a small lake that appeared after the postglacial Champlain Sea receded from the region, about 12 200 years ago. Its development followed a classical terrestrialization sequence and its hydrology has been stable since peat inception. A profile of over 8.5 m of organic matter was collected at the site, of which 2.5 m is peat and the rest is composed of lake sediments (gyttja). With the exception of a few tephra layers, the organic matter content exceeds 75 % of dry weight for the entire profile. Although it constitutes only 30 % of the profile depth, peat contains 48 % of the buried carbon because of its higher bulk density, and peat carbon accumulated at a rate of 88 g C m-2 yr-1. Overall, the site carbon density (including buried lake sediments) is 172 kg C m-2, a value comparable to the carbon density of many peatlands with much deeper peat profiles. The implications of these findings are discussed in the context of global peatland carbon inventories and peatland biogeochemistry.

  12. Holocene climate change and peatland dynamics in the Altai Mountains in Northwest China

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Yu, Z.; Li, Q.; Zhao, W.

    2013-12-01

    Here we present preliminary results from a peat-core record to investigate responses of upland vegetation and peatlands to Holocene climate change in the Altai Mountains. Chronology of a 650-cm-long peat core from the Iron Arshad Khan (IAK) peatland in the western Altai Mountains was controlled by 20 AMS dates on identifiable terrestrial macrofossils, covering the entire Holocene. Lithology results indicate that the peat accumulation initiated at 11 ka (1 ka =1000 cal BP), with a sharp increase in organic matter content to >80%. Plant macrofossil data show a sequence of changes from the peatlands dominated by Cyperaceae before 8.1 ka, to Cyperaceae and brown moss-dominated at 8-4.5 ka, Sphagnum and Cyperaceae-dominated at 4.5-2 ka, and to Cyperaceae-dominated again after 2 ka. Carbon accumulation rates were highest at >40 gC/m2/yr at 8.5-7 ka, more than doubled the Holocene average at the site. Pollen analysis shows the highest tree pollen (mainly from Picea) of up to 59% occurred at 8-6.4 ka, suggesting a warm and wet mid-Holocene 'optimum' climate in the region. Organic matter bulk density shows an increasing trend after 6.4 ka, suggesting increasing cumulative decomposition of accumulated peat. Our multi-proxy data indicate clear responses of peatland species composition, moisture conditions and carbon accumulation to regional climate change. The cooling and drying trend since the mid-Holocene was likely in response to the decrease in summer insolation and in westerly-induced precipitation. Furthermore, our results from this temperate highland peatland may shed new lights on understanding peatland carbon dynamics in northern Eurasia, including the largest peatland basin in West Siberia, as well as Holocene climate changes in central Asia.

  13. Burned and unburned peat water repellency: Implications for peatland evaporation following wildfire

    NASA Astrophysics Data System (ADS)

    Kettridge, N.; Humphrey, R. E.; Smith, J. E.; Lukenbach, M. C.; Devito, K. J.; Petrone, R. M.; Waddington, J. M.

    2014-05-01

    Water repellency alters soil hydrology after periods of wildfire, potentially modifying the ecosystem recovery to such disturbance. Despite this potential importance, the extent and severity of water repellency within burned peatlands and its importance in regulating peatland recovery to wildfire disturbance remains poorly understood. We characterised the water repellency of peat in a burned (one year post-fire) and unburned peatland in the Western Boreal Plain utilising the water drop penetration time and ethanol droplet molarity tests. Burned Sphagnum moss and feather moss sites had a more severe degree of water repellency than unburned sites, with differences being more pronounced between burned and unburned feather moss sites. Burned feather moss exhibited the most extreme water repellency, followed by unburned feather moss, and burned Sphagnum. The severity of water repellency varied with depth through the near surface of the moss/peat profile. This was most evident within the burned feathermoss where more extreme water repellency was observed at the near-surface compared to the surface, with the most extreme water repellency found at 1 and 5 cm depths. Unburned Sphagnum was completely hydrophilic at all depths. We suggest that the extreme water repellency in near-surface feather moss peat acts as a barrier that impedes the supply of water to the surface that replaces that lost via evaporation. This leads to drying of the near-surface vadose zone within feather moss areas and a concomitantly large decrease in peatland evaporation within feather moss dominated peatlands. This negative feedback mechanism likely enhances the resilience of such peatland to wildfire disturbance, maintaining a high water table position, thereby limiting peat decomposition. In comparison, such a feedback is not observed strongly within Sphagnum, leaving Sphagnum dominated peatlands potentially vulnerable to low water table positions post disturbance.

  14. Blanket peatland restoration leads to reduced storm runoff from headwater systems

    NASA Astrophysics Data System (ADS)

    Shuttleworth, Emma; Allott, Tim; Evans, Martin; Pilkington, Mike

    2016-04-01

    This paper presents data on the impact of largescale peatland restoration on catchment runoff from peatlands in northern England. The blanket peatlands of the Pennine hills are important sources of water supply and form the headwaters of major river systems. These peatlands are severely eroded with extensive gullying and bare peat resulting from the impacts of industrial pollution, overgrazing, wildfire and climatic change over the last millennium. In the last decade there has been a major programme of peatland restoration through re-vegetation and blocking of drainage lines in these systems. The Making Space for Water project has collected hydrological data from five micro-catchments(two restoration treatments, a bare peat control, a vegetated control and a previously restored site) over a four year period. This has allowed for both Before-After-Control-Intervention and Space for Time analysis of the impact of restoration on downstream runoff. Catchments became wetter following re-vegetation, water tables rose by 35 mm and overland flow production increased by 18%. Storm-flow lag times in restored catchments increased by up to 267 %, while peak storm discharge decreased by up to 37%. There were no statistically significant changes in percentage runoff, indicating limited changes to within-storm catchment storage. Natural flood management solutions are typically focussed around one of two main mechanisms, either enhanced storage of water in catchments or measures which slow transmission of water to channels and within channels. Upland peatlands are often mischaracterised as sponges and assumed to mitigate downstream runoff through additional storage. The results of this study suggest that whilst restoration of upland peatlands can lead to significant reductions in peak discharge, and has potential to contribute to natural flood risk management, the mechanism is an increase in catchment roughness and an associated decrease in flow velocities.

  15. Plant functional types define magnitude of drought response in peatland CO2 exchange.

    PubMed

    Kuiper, Jan J; Mooij, Wolf M; Bragazza, Luca; Robroek, Bjorn J M

    2014-01-01

    Peatlands are important sinks for atmospheric carbon (C), yet the role of plant functional types (PFTs) for C sequestration under climatic perturbations is still unclear. A plant-removal experiment was used to study the importance of vascular PFTs for the net ecosystem CO2 exchange (NEE) during (i.e., resistance) and after (i.e., recovery) an experimental drought. The removal of PFTs caused a decrease of NEE, but the rate differed between microhabitats (i.e., hummocks and lawns) and the type of PFTs. Ericoid removal had a large effect on NEE in hummocks, while the graminoids played a major role in the lawns. The removal of PFTs did not affect the resistance or the recovery after the experimental drought. We argue that the response of Sphagnum mosses (the only PFT present in all treatments) to drought is dominant over that of coexisting PFTs. However, we observed that the moment in time when the system switched from C sink to C source during the drought was controlled by the vascular PFTs. In the light of climate change, the shifts in species composition or even the loss of certain PFTs are expected to strongly affect the future C dynamics in response to environmental stress. PMID:24649652

  16. Developing Gyrfalcon surveys and monitoring for Alaska

    USGS Publications Warehouse

    Fuller, Mark R.; Schempf, Philip F.; Booms, Travis L.

    2011-01-01

    We developed methods to monitor the status of Gyrfalcons in Alaska. Results of surveys and monitoring will be informative for resource managers and will be useful for studying potential changes in ecological communities of the high latitudes. We estimated that the probability of detecting a Gyrfalcon at an occupied nest site was between 64% and 87% depending on observer experience and aircraft type (fixed-wing or helicopter). The probability of detection is an important factor for estimating occupancy of nesting areas, and occupancy can be used as a metric for monitoring species' status. We conclude that surveys of nesting habitat to monitor occupancy during the breeding season are practical because of the high probability of seeing a Gyrfalcon from aircraft. Aerial surveys are effective for searching sample plots or index areas in the expanse of the Alaskan terrain. Furthermore, several species of cliff-nesting birds can be surveyed concurrently from aircraft. Occupancy estimation also can be applied using data from other field search methods (e.g., from boats) that have proven useful in Alaska. We believe a coordinated broad-scale, inter-agency, collaborative approach is necessary in Alaska. Monitoring can be facilitated by collating and archiving each set of results in a secure universal repository to allow for statewide meta-analysis.

  17. EarthScope's Transportable Array in Alaska

    NASA Astrophysics Data System (ADS)

    Busby, R. W.; Woodward, R.; Hafner, K.

    2013-12-01

    Since 2003, EarthScope has been installing a network of seismometers, known as the Transportable Array-across the continental United States and southern Canada. The station deployments will be completed in the Conterminous US in the fall of 2013. Beginning in October, 2013, and continuing for 5 years, EarthScope's Transportable Array plans to create a grid of seismic sensors in approximately 300 locations In Alaska and Western Canada. The proposed station grid is 85 km, and target locations will supplement or enhance existing seismic stations operating in Alaska. When possible, they will also be co-located with existing GPS stations constructed by the Plate Boundary Observatory. We review the siting plans for stations, the progress towards reconnaissance and permitting, and detail the engineering concept of the stations. In order to be able to determine the required site conditions and descriptions of installation methods to the permitting agencies, the National Science Foundation (NSF) has been supporting exploratory work on seismic station design, sensor emplacement and communication concepts appropriate for the challenging high-latitude environment that is proposed for deployment. IRIS has installed several experimental stations to evaluate different sensor emplacement schemes both in Alaska and the lower-48 U.S. The goal of these tests is to maintain or enhance a station's noise performance while minimizing its footprint and the equipment, materials, and overall expense required for its construction. Motivating this approach are recent developments in posthole broadband seismometer design and the unique conditions for operating in Alaska, where most areas are only accessible by small plane or helicopter, and permafrost underlies much of the region. IRIS has experimented with different portable drills and drilling techniques to create shallow holes (1-5M) in permafrost and rock outcrops. Seasonal changes can affect the performance of seismometers in different

  18. Characteristics of carbonaceous aerosols emitted from peatland fire in Riau, Sumatra, Indonesia (2): Identification of organic compounds

    NASA Astrophysics Data System (ADS)

    Fujii, Yusuke; Kawamoto, Haruo; Tohno, Susumu; Oda, Masafumi; Iriana, Windy; Lestari, Puji

    2015-06-01

    Smoke emitted from Indonesian peatland fires has caused dense haze and serious air pollution in Southeast Asia such as visibility impairment and adverse health impacts. To mitigate the Indonesian peatland fire aerosol impacts, an effective strategy and international framework based on the latest scientific knowledge needs to be established. Although several attempts have been made, limited data exist regarding the chemical characteristics of peatland fire smoke for the source apportionment. In order to identify the key organic compounds of peatland fire aerosols, we conducted intensive field studies based on ground-based and source-dominated sampling of PM2.5 in Riau Province, Sumatra, Indonesia, during the peatland fire seasons in 2012. Levoglucosan was the most abundant compound among the quantified organic compounds at 8.98 ± 2.28% of the PM2.5 mass, followed by palmitic acid at 0.782 ± 0.163% and mannosan at 0.607 ± 0.0861%. Potassium ion was not appropriate for an indicator of Indonesian peatland fires due to extremely low concentrations associated with smoldering fire at low temperatures. The vanillic/syringic acids ratio was 1.06 ± 0.155 in this study and this may be a useful signature profile for peatland fire emissions. Particulate n-alkanes also have potential for markers to identify impact of Indonesian peatland fire source at a receptor site.

  19. Land-Cover Change Within the Peatlands Along the Rocky Mountain Front, Montana: 1937-2009

    NASA Astrophysics Data System (ADS)

    Klene, A. E.; Milbrath, J. T.; Shelly, J. S.

    2013-12-01

    While peatlands are globally abundant, the fens of the Rocky Mountain Front (RMF), are the eastern-most, rich, peatlands in Montana, and are unique wetland habitats in this region of semi-arid continental climate. The peatlands provide critical riparian connectivity between the mountains and the plains and are habitat for grizzly bears, wolves, and within just the 450 ha Pine Butte Fen at least 93 species of vascular plants, including seven of Montana's Plant Species of Concern. Aerial photographs of the nine peatlands along the RMF in Montana were analyzed in a GIS. The boundary of each wetland was hand-digitized and the area within was classified into land-cover types: total area, open fen, open water, woody vegetation, and non-wetland/agriculture. Changes in wetland extent and land-cover categories were evaluated from the earliest available imagery in 1937 to the last available imagery in 2009. Images prior to 1995 were orthorectified, and all georectified. Climate change, wildlife, and agriculture were examined as potential drivers of land-cover change at these sites. Results indicate little change in overall peatland area between 1937 and 2009 despite increasing air temperatures in the region. Approximately 16% of these peatlands is 'open fen' and that proportion remained stable over the last seventy years. Area of open water quadrupled and the number of ponds which could be delineated tripled over the study period, reflecting a recovering beaver population. The non-wetland/agricultural area halved over the course of the study, primarily due to declines in agriculture within the three largest remaining peatlands: Pine Butte Fen, McDonald Swamp, and the Blackleaf Creek wetland complex. Most of the first two fens were purchased outright by the Nature Conservancy (TNC) and they hold a conservation easement on the third (as well as two other fens), all of which have been been put in place since the late 1970s. One fen is owned by the State of Montana and another

  20. 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

  1. Isotopic partitioning of net ecosystem CO2 exchange reveals the importance of methane oxidation in a boreal peatland

    NASA Astrophysics Data System (ADS)

    Hasselquist, Niles; Peichl, Matthias; Öquist, Mats; Crill, Patrick; Nilsson, Mats

    2016-04-01

    Partitioning net ecosystem CO2 exchange (NEE) into its different flux components is crucial as it provides a mechanistic framework to better assess how the terrestrial carbon cycle may respond to projected environmental change. This is especially important for northern boreal peatlands, which store approximately one-quarter of the world's soil carbon and yet at the same time are projected to experience some of the greatest environmental changes in the future. Using an experimental setup with automated chambers for measuring NEE (transparent chambers), ecosystem respiration (Reco; opaque chambers) and heterotrophic respiration (Rh; opaque chambers on vegetation-free trenched plots) in combination with continuous measurements of δ13C using near-infrared, diode-laser-based cavity-ring down spectroscopy (Picarro G1101-i analyzer), we partitioned NEE of CO2 into gross primary productivity (GPP), ecosystem respiration (Reco), heterotrophic respiration (Rh) and autotrophic respiration (Ra) using two different approaches (i.e., chamber- and isotope-based methods) in a boreal peatland in northern Sweden (Degerö). Given that δ13C was continuously measured in each chamber, we were also able to further partition Rh into soil organic matter (SOM) mineralization by saprotrophic microbes and the oxidation of methane (CH4) by methanotrophic bacteria. During the ten day measurement period (in late July 2014), the average daily NEE flux at the mire was -0.6 g C m-2 d-1. Overall, the two partitioning approaches yielded similar estimates for the different NEE component fluxes. Average daily fluxes of Rh and Ra were similar in magnitude, yet these two flux components showed contrasting diurnal responses: Ra was greatest during the day whereas there was little diurnal variation in Rh. In general, average 13C signature of CO2 efflux from the Rh chambers (-41.1 ± 0.6 ‰) was between the 13C signature of SOM (-25.8 ± 0.6 ‰) and CH4 in pore water (-69.0 ± 0.8 ‰). Assuming that

  2. The long-term fate of permafrost peatlands under rapid climate warming

    NASA Astrophysics Data System (ADS)

    Swindles, Graeme T.; Morris, Paul J.; Mullan, Donal; Watson, Elizabeth J.; Turner, T. Edward; Roland, Thomas P.; Amesbury, Matthew J.; Kokfelt, Ulla; Schoning, Kristian; Pratte, Steve; Gallego-Sala, Angela; Charman, Dan J.; Sanderson, Nicole; Garneau, Michelle; Carrivick, Jonathan L.; Woulds, Clare; Holden, Joseph; Parry, Lauren; Galloway, Jennifer M.

    2015-12-01

    Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed in response to climatic warming, culminating in collapse of the peat domes. Commonalities between study sites lead us to propose a five-phase model for permafrost peatland response to climatic warming. This model suggests a shared ecohydrological trajectory towards a common end point: inundated Arctic fen. Although carbon accumulation is rapid in such sites, saturated soil conditions are likely to cause elevated methane emissions that have implications for climate-feedback mechanisms.

  3. Permafrost peatland dynamics during the last millennia in NE European Russia and Finnish Lapland

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Väliranta, Minna; Piilo, Sanna; Amesbury, Matthew; Gallego-Sala, Angela; Charman, Dan

    2016-04-01

    Permafrost peatlands cover vast areas in circum-Arctic regions. Since the 1980s, annual temperatures in these areas have risen by ca. 2 °C and warming is projected to continue. Accordingly, the large carbon store in these peatlands may therefore be threatened. Alternatively, warming may increase productivity more than decomposition and peat accumulation rates may increase. To better understand how high latitude permafrost peatlands have responded to recent warming and what might be their future fate, we carried out detailed studies on two permafrost peatlands in NE Russia and two in Finnish Lapland. Our study methods included high resolution testate amoeba, plant macrofossil, C/N analyses, together with 210Pb and radiocarbon dating. We reconstructed changes in hydrological conditions, plant composition, and peat and carbon accumulation rates. Our preliminary results showed large variations in peat accumulation rates even within a very small area. Furthermore, testate amoeba and plant macrofossil data suggest variations in hydrological conditions during the last millennia. In the future, we will compare our regional data derived from different peatlands to each other, to climate reconstructions and to measured meteorological data.

  4. Seasonal changes in dominant bacterial taxa from acidic peatlands of the Atlantic Rain Forest.

    PubMed

    Etto, Rafael Mazer; Cruz, Leonardo Magalhães; da Conceição Jesus, Ederson; Galvão, Carolina Weigert; Galvão, Franklin; de Souza, Emanuel Maltempi; de Oliveira Pedrosa, Fábio; Reynaud Steffens, Maria Berenice

    2014-09-01

    The acidic peatlands of southern Brazil are essential for maintenance of the Atlantic Rain Forest, one of the 25 hot-spots of biodiversity in the world. While these ecosystems are closely linked to conservation issues, their microbial community ecology and composition remain unknown. In this work, histosol samples were collected from three acidic peatland regions during dry and rainy seasons and their chemical and microbial characteristics were evaluated. Culturing and culture-independent approaches based on SSU rRNA gene pyrosequencing were used to survey the bacterial community and to identify environmental factors affecting the biodiversity and microbial metabolic potential of the Brazilian peatlands. All acidic peatlands were dominated by the Acidobacteria phylum (56-22%) followed by Proteobacteria (28-12%). The OTU richness of these phyla and the abundance of their Gp1, Gp2, Gp3, Gp13, Rhodospirillales and Caulobacteriales members varied according to the period of collection and significantly correlated with the rainy season. However, despite changes in acidobacterial and proteobacterial communities, rainfall did not affect the microbial metabolic potential of the southern Brazilian Atlantic Rain Forest peatlands, as judged by the metabolic capabilities of the microbial community. PMID:24893336

  5. Simulating the sensitivity of northern peatlands to climate change: coupling hydrology and carbon dynamics

    NASA Astrophysics Data System (ADS)

    Roulet, N. T.; Wu, J.

    2009-12-01

    The McGill Wetland Model (MWM) coupled to the Canadian Land Surface Scheme adapted for peat accumulating wetlands (CLASS3w) were used to examine the sensitivity of two types of northern peatlands - ombrotrophic bogs and mineral poor fens, for four different scenarios (A1B, A2, B1 and Commitment) of future climate change based in simulations of the CCCma-GCM. Simulated changes in the components and overall carbon exchanges were considerably different between runs of MWM alone and MWM coupled to CLASS3w indicating the importance of examining peatland biogeochemistry, hydrology and surface climate synergistically rather than as separate components. In all simulations, the carbon sink in the bog and fen decreased, but the fen in the A1B and A2 scenarios flipped from being a sink to a source for atmospheric CO2 by the second half of the 21st century. In these two cases, the source of extra carbon from the mineralization of peat could be as much as a 1 Pg C yr-1 but these simulations also revealed some critical limitations of our approach need addressing before we are prepared to draw broad scale regional or hemispheric conclusions. The two most immediate problems are how to simulate realistically a) the external lateral water inputs to a fen peatland since it can be a critical source of water offsetting reductions in water storage if evapotranspiration increases more than precipitation, and b) changes in peatland vegetation structure with changes in peatlands water storage.

  6. The long-term fate of permafrost peatlands under rapid climate warming

    PubMed Central

    Swindles, Graeme T.; Morris, Paul J.; Mullan, Donal; Watson, Elizabeth J.; Turner, T. Edward; Roland, Thomas P.; Amesbury, Matthew J.; Kokfelt, Ulla; Schoning, Kristian; Pratte, Steve; Gallego-Sala, Angela; Charman, Dan J.; Sanderson, Nicole; Garneau, Michelle; Carrivick, Jonathan L.; Woulds, Clare; Holden, Joseph; Parry, Lauren; Galloway, Jennifer M.

    2015-01-01

    Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed in response to climatic warming, culminating in collapse of the peat domes. Commonalities between study sites lead us to propose a five-phase model for permafrost peatland response to climatic warming. This model suggests a shared ecohydrological trajectory towards a common end point: inundated Arctic fen. Although carbon accumulation is rapid in such sites, saturated soil conditions are likely to cause elevated methane emissions that have implications for climate-feedback mechanisms. PMID:26647837

  7. The long-term fate of permafrost peatlands under rapid climate warming.

    PubMed

    Swindles, Graeme T; Morris, Paul J; Mullan, Donal; Watson, Elizabeth J; Turner, T Edward; Roland, Thomas P; Amesbury, Matthew J; Kokfelt, Ulla; Schoning, Kristian; Pratte, Steve; Gallego-Sala, Angela; Charman, Dan J; Sanderson, Nicole; Garneau, Michelle; Carrivick, Jonathan L; Woulds, Clare; Holden, Joseph; Parry, Lauren; Galloway, Jennifer M

    2015-01-01

    Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed in response to climatic warming, culminating in collapse of the peat domes. Commonalities between study sites lead us to propose a five-phase model for permafrost peatland response to climatic warming. This model suggests a shared ecohydrological trajectory towards a common end point: inundated Arctic fen. Although carbon accumulation is rapid in such sites, saturated soil conditions are likely to cause elevated methane emissions that have implications for climate-feedback mechanisms. PMID:26647837

  8. Geophysical Evidence for Abiotic Controls on Peatland Patterning at Multiple Scales

    NASA Astrophysics Data System (ADS)

    Nolan, J.; Slater, L.; Glaser, P.; Comas, X.; O'Brien, M.

    2007-12-01

    The autogenic and allogenic controls on the formation of distinctive and dramatic vegetation patterning found in northern peatlands remain unclear. Groundwater model studies and investigations using point measurements lack intensive data over multiple scales, primarily due to the intensive time required and difficult logistics required to work in these remote ecosystems. We provide geophysical evidence that lithological controls on vegetation patterning exist at multiple scales in ombrotrophic peatlands of northern Minnesota and Maine. Surveys using electrical imaging methods (including resistivity, induced polarization, and ground penetrating radar) at sites in the Red Lake Peatland Complex (160 km2), as well as Kanokolus Bog (1.65 km2) and the Caribou Bog Peatland Complex (22 km2) in Maine reveal sharp vegetation gradients coinciding with changes in the mineral soil lithology. In contrast, large-scale, continuous, patterned zones found in the Red lake Complex coincide with strikingly uniform mineral soil lithology as inferred from the geophysical images. Small-scale (0.3 km2) vegetation patterns observed in Caribou Bog also coincide with small scale lithologic changes in both the mineral and organic deposits. These results provide evidence that the subsurface hydrogeologic framework regulates vegetation patterning in peatlands across multiple scales, presumably by regulating (1) the supply of mineral solutes to the surface vegetation water, and (2) water levels within the organic soil.

  9. Extraction, drainage, rewetting, flooding - Patterns of greenhouse gas turnover in restoring temperate peatlands

    NASA Astrophysics Data System (ADS)

    Glatzel, Stephan

    2016-04-01

    The disturbance of natural peatlands destroys carbon sink and is often associated with nitrous oxide emissions. Therefore, the general efforts to mitigate greenhouse gas sources and to create carbon sinks also include peatland restoration. The variety of peatland type (most importantly bog or fen), use (extraction or agriculture), and restoration technique (rewetting or flooding) result in specific patterns of greenhouse gas uptake or emission. Based on examples from own work, I present an overview of the greenhouse gas turnover of following sites: • Cutover peat bogs in Eastern Canada and following rewetting, flooding, and abandonment • Drained cutover and agriculturally used peat bogs in Northern Germany and following extensive agricultural management, paludiculture, rewetting, flooding, and abandonment • Drained agriculturally used fens in Northern Germany and following flooding and paludiculture I show that rewetting, but not flooding may succeed in re-establishing long-term carbon sinks with low methane release rates comparable to the greenhouse gas turnover known from natural peatlands. Flooding risks creating, at least in the short term, extremely strong methane sources. Extensive agricultural management and paludiculture may result in low methane, carbon dioxide and nitrous oxide release rates and could be a sensible option when aiming at reconciling peatland use and protection.

  10. Manure derived biochar can successfully replace phosphate rock amendment in peatland restoration.

    PubMed

    Pouliot, Rémy; Hugron, Sandrine; Rochefort, Line; Godbout, Stéphane; Palacios, Joahnn H; Groeneveld, Elisabeth; Jarry, Isabelle

    2015-07-01

    Phosphate rock fertilization is commonly used in peatland restoration to promote the growth of Polytrichum strictum, a nurse plant which aids the establishment of Sphagnum mosses. The present study tested whether 1) phosphorus fertilization facilitates the germination of P. strictum spores and 2) biochar derived from local pig manure can replace imported phosphate rock currently used in peatland restoration. Various doses of biochar were compared to phosphate rock to test its effect directly on P. strictum stem regeneration (in Petri dishes in a growth chamber) and in a simulation of peatland restoration with the moss layer transfer technique (in mesocoms in a greenhouse). Phosphorus fertilization promoted the germination of P. strictum spores as well as vegetative stem development. Biochar can effectively replace phosphate rock in peatland restoration giving a new waste management option for rural regions with phosphorus surpluses. As more available phosphorus was present in biochar, an addition of only 3-9 g m(-2) of pig manure biochar is recommended during the peatland restoration process, which is less than the standard dose of phosphate rock (15 g m(-2)). PMID:25897506

  11. Natural zinc enrichment in peatlands: Biogeochemistry of ZnS formation

    NASA Astrophysics Data System (ADS)

    Yoon, Soh-joung; Yáñez, Carolina; Bruns, Mary Ann; Martínez-Villegas, Nadia; Martínez, Carmen Enid

    2012-05-01

    Peatlands effectively retain heavy metals and prevent stream and watershed contamination. Sulfate reduction is considered the most significant process of metal immobilization in natural wetlands and microbial sulfate reduction is the presumed mechanism that results in the precipitation of metal sulfides. In this study, we examined the biogeochemical mechanisms involved in zinc retention and accumulation in a metalliferous peatland of western New York. In the reducing conditions of these peatlands zinc sulfides occurred as framboidal aggregates of sphalerite and polytypic wurtzite (2nH, n ⩾ 2) nanocrystallites associated with bacterial cells and organic matter. Bacterial cells were co-located with ZnS inside peat particles where the microenvironment remained anoxic. The peat zinc sulfide was depleted in 34S isotopes relative to the sulfate supplied to the peatland by 18-34 per mill, implicating its biological formation. Extraction of microbial community DNA from peat samples yielded diverse PCR amplicons from dissimilatory sulfite reductase (dsrAB) genes, indicating varied bacterial taxa capable of reducing forms of oxidized sulfur. Nanocrystals with distinct structural features were observed in samples containing contrasting dsrAB sequences. The results of this investigation provide clear evidence that microorganisms can influence the chemical forms of heavy metals in peatland environments. Our findings also provide insight into the conditions necessary to promote the immobilization of chalcophile elements in engineered systems for the treatment of acid mine drainage and wastewater effluents.

  12. Resilience in heterogeneous landscapes: The effect of topography on resilience of carbon uptake in northern peatlands

    NASA Astrophysics Data System (ADS)

    Nijp, Jelmer; Temme, Arnaud; van Voorn, George; Teuling, Ryan; Soons, Merel; Kooistra, Lammert

    2016-04-01

    Northern peatlands contain and store enormous amounts of carbon, and therefore represent an important component of the carbon cycle of the earth. In these wetland ecosystems, the quality of the soil added to the soil surface is determined by the type of peat-forming plants, and affects the carbon accumulated in the peat soil later formed and overall ecosystem functioning. Peatland vegetation is frequently organized in alternating dry hummocks with wet hollows. Such patterned vegetation is associated with different soil carbon accumulation rates, and may develop due to various self-regulating processes originating from ecohydrological feedbacks. Simulation models have shown that vegetation patterning may promote the resilience of peatlands to environmental change (climate, land use), hence maintaining their function as carbon sink. Critically, the results of these model studies rely on the fundamental assumption that environmental conditions are spatially homogeneous. Yet, in real landscape settings, catchment topography has a major impact on water flow and nutrient availability, and is expected to alter vegetation patterning. However, whether, where and how topography affects vegetation patterning in peatlands and associated resilience of ecosystem service provision remains unknown. By combining field observations, remote sensing, and dynamic simulation models (used both as 'sandbox' and 'resilience calculator' for given geomorphological settings), we determine how landscape topography affects ecohydrological processes, vegetation patterning, and associated resilience to environmental change in northern peatlands.

  13. Moss and peat hydraulic properties are optimized to maximise peatland water use efficiency

    NASA Astrophysics Data System (ADS)

    Kettridge, Nicholas; Tilak, Amey; Devito, Kevin; Petrone, Rich; Mendoza, Carl; Waddington, Mike

    2016-04-01

    Peatland ecosystems are globally important carbon and terrestrial surface water stores that have formed over millennia. These ecosystems have likely optimised their ecohydrological function over the long-term development of their soil hydraulic properties. Through a theoretical ecosystem approach, applying hydrological modelling integrated with known ecological thresholds and concepts, the optimisation of peat hydraulic properties is examined to determine which of the following conditions peatland ecosystems target during this development: i) maximise carbon accumulation, ii) maximise water storage, or iii) balance carbon profit across hydrological disturbances. Saturated hydraulic conductivity (Ks) and empirical van Genuchten water retention parameter α are shown to provide a first order control on simulated water tensions. Across parameter space, peat profiles with hypothetical combinations of Ks and α show a strong binary tendency towards targeting either water or carbon storage. Actual hydraulic properties from five northern peatlands fall at the interface between these goals, balancing the competing demands of carbon accumulation and water storage. We argue that peat hydraulic properties are thus optimized to maximise water use efficiency and that this optimisation occurs over a centennial to millennial timescale as the peatland develops. This provides a new conceptual framework to characterise peat hydraulic properties across climate zones and between a range of different disturbances, and which can be used to provide benchmarks for peatland design and reclamation.

  14. The flux of organic matter through a peatland ecosystem - evidence from thermogravimetric analysis

    NASA Astrophysics Data System (ADS)

    Worrall, Fred; Moody, Catherine; Clay, Gareth

    2016-04-01

    Carbon budgets of peatlands are now common and studies have considered nitrogen, oxygen and energy budgets, but no study has considered the whole composition of the organic matter as it transfers through and into a peatland. Organic matter samples were taken from each organic matter reservoir found in and each fluvial flux from a peatland and analysed the samples by thermogravimetric analysis. The samples analysed were: aboveground, belowground, heather, mosses and sedges, litter layer, a peat core, and monthly samples of particulate and dissolved organic matter. All organic matter samples were taken from a 100% peat catchment within Moor House National Nature Reserve in the North Pennines, UK, and collected samples were compared to standards of lignin, cellulose, humic acid and plant protein. Results showed that the thermogravimetric trace of the sampled organic matter were distinctive with the DOM traces being marked out by very low thermal stability relative other organic matter types. The peat profile shows a significant trend with depth from vegetation- to lignin-like composition. When all traces are weighted according to the observed dry matter and carbon budgets for the catchment then it is possible to judge what has been lost in the transition through and into the ecosystem. By plotting this "lost" trace it possible to assess its composition which is either 97% cellulose and 3% humic acid or 92% and 8% lignin. This has important implications for what controls the organic matter balance of peatlands and it suggests that the oxidation state (OR) of peatland is less than 1.

  15. Simulating the long-term response of peatlands to extraction and post-extraction management strategies

    NASA Astrophysics Data System (ADS)

    Quillet, Anne; Roulet, Nigel; Wu, Jianghua

    2016-04-01

    Peatlands have been and remain exploited either for agricultural purposes, forestry, peat extraction or infrastructure development in the northern latitudes as well as in the tropics. Modelling current and future carbon exchanges in peatlands thus requires further understanding of carbon dynamics in drained, exploited and restored peatlands. This study aimed at quantifying the centennial to millennial carbon balance in extracted and restored peatlands. On-site data measurements only started recently and only cover up to 15 years. The chosen approach was thus based on modelling. We modified the Holocene Peat Model (Frolking et al. 2010) to simulate peat extraction and restoration and calculate the carbon balance at different stages of exploitation and restoration. The model simulates drainage occurring prior to and during peat extraction, changes in peat bulk density and the specific vegetation succession occurring during the restoration process. As in the previous version of HPM, vegetation dynamics and interactions between vegetation and ecohydrology were included in the simulations. Simulation results offered an estimate of the amount of carbon accumulated in the peatland prior to exploitation as well as the carbon loss during exploitation. Estimates of current and future net carbon accumulation/loss, associated with different management scenarios, such as state-of-the-art restoration, drainage blocking or abandonment, gave an insight into the benefits of restoration and moreover into the millennial scale impact of peat extraction.

  16. 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

  17. Metamorphic facies map of Alaska

    SciTech Connect

    Dusel-Bacon, C.; O-Rourke, E.F.; Reading, K.E.; Fitch, M.R.; Klute, M.A.

    1985-04-01

    A metamorphic-facies of Alaska has been compiled, following the facies-determination scheme of the Working Group for the Cartography of the Metamorphic Belts of the World. Regionally metamorphosed rocks are divided into facies series where P/T gradients are known and into facies groups where only T is known. Metamorphic rock units also are defined by known or bracketed age(s) of metamorphism. Five regional maps have been prepared at a scale of 1:1,000,000; these maps will provide the basis for a final colored version of the map at a scale of 1:2,500,000. The maps are being prepared by the US Geological Survey in cooperation with the Alaska Division of Geological and Geophysical Surveys. Precambrian metamorphism has been documented on the Seward Peninsula, in the Baird Mountains and the northeastern Kuskokwim Mountains, and in southwestern Alaska. Pre-Ordovician metamorphism affected the rocks in central Alaska and on southern Prince of Wales Island. Mid-Paleozoic metamorphism probably affected the rocks in east-central Alaska. Most of the metamorphic belts in Alaska developed during Mesozoic or early Tertiary time in conjuction with accretion of many terranes. Examples are Jurassic metamorphism in east-central Alaska, Early Cretaceous metamorphism in the southern Brooks Range and along the rim of the Yukon-Kovyukuk basin, and late Cretaceous to early Tertiary metamorphism in the central Alaska Range. Regional thermal metamorphism was associated with multiple episodes of Cretaceous plutonism in southeastern Alaska and with early Tertiary plutonism in the Chugach Mountains. Where possible, metamorphism is related to tectonism. Meeting participants are encouraged to comment on the present version of the metamorphic facies map.

  18. Reducing uncertainty in methane emission estimates from permafrost peatlands

    NASA Astrophysics Data System (ADS)

    Christensen, Torben R.

    2016-04-01

    Reducing uncertainty in methane emission estimates from permafrost peatlands Torben R. Christensen1,2 and coworkers 1) Department of Physical Geography and Ecosystem Science, Lund University, Sweden 2) Arctic Research Centre, Aarhus University, Denmark Depending on factors including temperature, snow duration and soil moisture conditions, emissions of the greenhouse gas methane from permafrost peatlands can vary by factors of 2-4 between years. This variability is clear in atmospheric measurements of the gas, but a lack of ground-based data is making it hard to locate the methane sources responsible. Methane monitoring in the Arctic is expensive, requiring sophisticated analysis equipment such as power requiring laser spectrometer analysis made in remote places. This also puts demands on the logistics where infrastructures and field stations that offer line-power in the field are in high demand but very rarely found. Research projects therefore typically focus on one site, and run for a year or two. Longer term monitoring programs, which document climate, hydrology, phenology and population dynamics of birds and mammals, rarely include carbon fluxes since it is technically challenging to measure. One that does is the Greenland Ecosystem Monitoring program that started at the Zackenberg research station, which has recorded substantial methane flux variations for almost a decade in North-east Greenland. Such multi-year studies show that, while there is some connection between the amounts of methane released from one year to the next, accurate forecasting is difficult. They also highlight the importance of extending monitoring beyond the growing period into the frozen season, both in spring and autumn. A spatially distributed network of long-term monitoring stations in the Arctic, with consistency between measurements, is badly needed to improve this situation. Productive methane 'hot spots', many sporadic, have also been identified in recent studies. By ventilating

  19. Spatial patterns of denitrification and its functional genes in peatlands

    NASA Astrophysics Data System (ADS)

    Mander, Ülo; Ligi, Teele; Truu, Marika; Truu, Jaak; Pärn, Jaan; Egorov, Sergey; Järveoja, Järvi; Vohla, Christina; Maddison, Martin; Soosaar, Kaido; Oopkaup, Kristjan; Teemusk, Alar; Preem, Jens-Konrad; Uuemaa, Evelyn

    2014-05-01

    This study is aimed to analyse relationships between the environmental factors and the spatial distribution of the main functional genes nirS, nirK, and nosZ regulating the denitrification process. Variations in hydrological regime, soil temperature and peat quality have been taken into the consideration at both local and global scale. Measurements of greenhouse gas (GHG) emissions using static chambers, groundwater analysis, gas and peat sampling for further laboratory analysis has been conducted in various peatlands in Iceland (two study areas, 2011), Transylvania/Romania (2012), Santa Catarina/Brazil (2012), Quebec/Canada (2012), Bashkortostan/Russian Federation (two study areas, 2012), Sichuan/China (2012), Estonia (two study areas, 2012), Florida/USA (2013, Sologne/France (2013), Jugra in West Siberia/Russia (2013), Uganda (2013), French Guyana (two study areas, 2013), Tasmania (two study areas, 2014) and New Zealand (two study areas, 2014). In each study area at least 2 transects along the groundwater depth gradient, one preferably in undisturbed, another one in drained area, and at least 3 rows of sampling sites (3-5 replicate chambers and 1 piezometer and soil sampling plot in each) in both has been established for studies. In each transect GHG emission was measured during 2-3 days in at least 5 sessions. In addition, organic sediments from the artificial riverine wetlands in Ohio/USA in 2009 and relevant gas emission studies have been used in the analyses. In the laboratories of Estonian University of Life Sciences and the University of Tartu, the peat chemical quality (pH, N, P, C, NH4, NO3) and N2O, CO2, and CH4 concentration in gas samples (50mL glass bottles and exetainers) were analysed. The peat samples for further pyrosequencing and qPCR analyses are stored in fridge by -22oC. This presentation will consider the variation of GHG emissions and hydrological conditions in the study sites. In addition, several selected biophysical factors will be taken

  20. Combining Research and Pedagogy in a Field-based Inquiry at a Temperate Peatland

    NASA Astrophysics Data System (ADS)

    Froburg, E.; Varner, R. K.; Bryce, J. G.; Hale, S. R.; Johnson, J. E.; Graham, K.; none

    2011-12-01

    The University of New Hampshire's Transforming Earth System Science Education (UNH TESSE) program is designed to enrich the Earth System Science (ESS) content knowledge and inquiry-based pedagogical skills of in-service and pre-service teachers who either currently teach or plan to teach earth science curricula. This goal is promoted through authentic research experiences coupled with assignments that ask teachers to apply their new understanding of pedagogy and content in the classroom. Teachers participate in an intensive 2-week summer institute followed by an academic-year program during which they receive support from geoscience graduate fellow(s). Throughout the two-week institute, teachers receive foundational ESS content instruction and participate in field experiences that highlight different aspects of the research process. The culminating field experience provides an opportunity for the participants to conduct an investigation that is a condensed version of the full scientific research process, while modeling the pedagogical context of a k-12 classroom. Teachers participate in a full cycle of research/inquiry, often for the first time, and are also required to face many of the constraints that they will have in the classroom. Teachers work in groups of 3-4 on a self-selected research topic based on research being completed at Sallie's Fen, NH, USA, a long-term peatland research site. The investigation takes place over two days, and is comprised of, 1) faculty-presented background information on the relevant scientific concepts, the field-site, published research findings, and the instrumentation and methodologies of data collection, 2) coached development of a research question and hypothesis; 3) field-based data collection and analysis; and 4) synthesis and group presentation of findings in a 15 minute "science talk" format. Upon completion of the science talk, teachers are asked to reflect on the classroom application of the process.

  1. 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

  2. NGEE Arctic Webcam Photographs, Barrow Environmental Observatory, Barrow, Alaska

    DOE Data Explorer

    Bob Busey; Larry Hinzman

    2012-04-01

    The NGEE Arctic Webcam (PTZ Camera) captures two views of seasonal transitions from its generally south-facing position on a tower located at the Barrow Environmental Observatory near Barrow, Alaska. Images are captured every 30 minutes. Historical images are available for download. The camera is operated by the U.S. DOE sponsored Next Generation Ecosystem Experiments - Arctic (NGEE Arctic) project.

  3. Use of stabile isotopes and tracers to detect preferential flow patterns in a peatland treating municipal wastewater

    NASA Astrophysics Data System (ADS)

    Ronkanen, Anna-Kaisa; Kløve, Bjørn

    2007-12-01

    SummaryThe understanding of flow processes is one of the key elements in evaluating treatment efficiency in constructed wetlands. This study use a new method based on analysis of stabile oxygen and hydrogen isotope distributions in surface water in order to find water flow pathways in a treatment system established on a natural peatland in Ruka, Finland. The 18O/ 16O distributions of surface water samples were analysed in three field campaigns (2002, 2004, and 2005) and 2H/ 1H distribution in one field campaign (2002). Two conventional tracer (KBr and KI) tests and a tracer (NaCl) test in ground water tubes were conducted to study residence times and soil water flow characteristics. Online registration of electrical conductivity and temperature were used to analyse the NaCl experiment. The results showed clear spatial differences in 18O/ 16O distributions that were similar in each field campaign. Both 18O/ 16O and 2H/ 1H also varied clearly with depth until 40 cm. The results indicate that a strong preferential pathway exists in the wetland and that the water flows mainly in the top of peat layer. The observed flow path was the reason for the varying NH 4-N distribution showing that a large potential area for nutrient removal is not used. The results show that the isotope method can be used to evaluate the water flow structure in peatlands and determinate the active flow area for wastewater purification. Along with the traditional tracer test the method can be used to estimate the active flow volume. A modification to the potential residence time equation is proposed by including active flow area, flow depth and an effective porosity.

  4. Aerobic and Anaerobic Respiration in Profiles of Polesie Lubelskie Peatlands

    NASA Astrophysics Data System (ADS)

    Szafranek-Nakonieczna, Anna; Stêpniewska, Zofia

    2014-04-01

    Soil respiration is a very important factor influencing carbon deposition in peat and reflecting the intensity of soil organic matter decomposition, root respiration, and the ease of transporting gases to the surface. Carbon dioxide release from three different peat soil profiles (0-80 cm) of the Polesie Lubelskie Region (Eastern Poland) was analyzed under laboratory conditions. Peat samples were incubated at 5, 10, and 20°C in aerobic and anaerobic environments, and their CO2-evolution was analyzed up to 14 days. The respiration activity was found to be in the range of 0.013-0.497 g CO2 kg-1 DW d-1. The respiratory quotient was estimated to be in the range of 0.51-1.51, and the difference in respiration rates over 10°C ranged between 4.15 and 8.72 in aerobic and from 1.15 to 6.53 in anaerobic conditions. A strong influence of temperature, depth, the degree of peat decomposition, pH, and nitrate content on respiration activity was found. Lack of oxygen at low temperature caused higher respiration activity than under aerobic conditions. These results should be taken into account when the management of Polish peatlands is considered in the context of climate and carbon storage, and physicochemical properties of soil in relation to soil respiration activity are considered.

  5. Climate change impact on peatland and forest ecosystems of Russia

    SciTech Connect

    Kondrasheva, N.Yu.; Kobak, K.I.; Turchinovich, I.Ye.

    1996-12-31

    Paleoclimatic and paleobotanic reconstructions allow a conclusion that ecosystems and natural zones significantly changed due to climate fluctuations. The average long-term carbon accumulation in peatlands of Russia was estimated as 45.6 mln tons of carbon per year. During the Holocene the rate of peat accumulation changed. During the Subboreal period the rate of peat accumulation gradually decreased to 17 gC/m2 yr, reaching its lowest value in the Subatlantic period. Apparently, the rate of peat accumulation decreased in Subboreal period due to sharp cooling and precipitation decrease. Future rates of peat accumulation might be higher than the present one. Forest ecosystems of north-western Russia also significantly changed during the Holocene. In Atlantic time the boundary between middle and south taiga was located 500 km northward compared to the present and broad-leaved forest occupied large areas. According to their forecast, a mean global air temperature increase by 1.4 C is expected to result in a considerable decrease in coniferous forest area and an increase in mixed and broad-leaved forest area.

  6. The carbon functional group budget of a peatland

    NASA Astrophysics Data System (ADS)

    Moody, Catherine; Worrall, Fred; Clay, Gareth; Apperley, David

    2016-04-01

    Organic matter samples were taken from each organic matter reservoir and fluvial flux found in a peatland and analysed by elemental analysis for carbon, hydrogen, nitrogen and oxygen content, and by 13C solid state nuclear magnetic resonance (NMR) for functional group composition. The samples analysed were: aboveground, belowground, heather, mosses and sedges, litter layer, four different depths from a peat core, and monthly samples of fluvial particulate and dissolved organic matter. All organic matter samples were taken from a 100% peat catchment within Moor House National Nature Reserve in the North Pennines, UK. The proportion of carbon atoms from each of the eight carbon functional groups (C-alkyl, N-alkyl/methoxyl C, O-alkyl, O2-alkyl/acetal C, aromatic/unsaturated C, phenolic C, aldehyde/ketone C and amide/carboxyl C) from each type of organic matter were combined with an existing carbon budget from the same site, to give a functional group carbon budget. The budget results show that the ecosystem is accumulating N-alkyl/methoxyl C, O-alkyl, O2-alkyl/acetal C and phenolic C groups, but losing C-alkyl, aromatic/unsaturated C, amide/carboxyl C and aldehyde/ketone C. Comparing the functional group compositions between the sampled organic matter pools shows that DOM arises from two distinct sources; from the peat itself and from a vegetation source.

  7. Control of Methane Production and Exchange in Northern Peatlands

    NASA Technical Reports Server (NTRS)

    Crill, Patrick

    1997-01-01

    This proposal has successfully supported studies that have developed unique long ten-n datasets of methane (CH4) emissions and carbon dioxide (CO2) exchange in order to quantify the controls on CH4 production and exchange especially the linkages to the carbon cycle in northern peatlands. The primary research site has been a small fen in southeastern New Hampshire where a unique multi-year data baseline of CH4 flux measurements was begun (with NASA funding) in 1989. The fen has also been instrumented for continuous hydrological and meteorological observations and year-round porewater sampling. Multiyear datasets of methane flux are very valuable and very rare. Datasets using the same sampling techniques at the same sites are the only way to assess the effect of the integrated ecosystem response to climatological variability. The research has had two basic objectives: 1. To quantify the effect of seasonal and interannual variability on CH4flux. 2. To examine process level controls on methane dynamics.

  8. Hydrological factors behind the water quality changes due to restoration in boreal peatlands

    NASA Astrophysics Data System (ADS)

    Ronkanen, Anna-Kaisa; Marttila, Hannu; Walle Menberu, Meseret; Irannezhad, Masoud; Tahvanainen, Teemu; Penttinen, Jouni; Hokkanen, Reijo; Klöve, Björn

    2016-04-01

    Recovery of hydrological conditions after restoration in previously drained peatlands is typically faster process compared to changes in runoff water quality. Often nutrient load from restored sites increase remarkably during restoration operation and reduce over time when conditions stabilize. However, in some sites nutrient load can remain high for long periods of time which increase negative effects of restoration on downstream water bodies. The factors and challenges behind these processes are poorly understood in practical catchment restoration planning. This study aims to understand factors affecting water quality changes after peatland restoration. Totally 43 peatlands areas of which 24 sites were previously drained and restored during the study and 19 sites at their pristine stage (control sites) were included to the study. The control pristine sites had as little anthropogenic disturbances as possible and the sites were chosen so that the paired study sites closely share similar peatland type, nutrient status and weather conditions. Pore water quality (total phosphorus, total nitrogen, dissolved organic carbon, pH, electric conductivity and colour) was measured from all sites and runoff quality and amount from 7 sites in the years 2008-2014. Measured parameters, different peatland types and nutrient loads were studied together with numerous hydrological parameters (variation in water table fluctuations, peat pore water recharge coefficient, physical parameters of peat e.g. specific yield, degree of humification) by statistical methods. Differences in water table dependent hydrological conditions indicate e.g. flow paths and residence time of water that is known to have effect on runoff water quality. As a result, water table related hydrological changes following restoration are as well assumed to explain alterations in water quality in different peatland types. In addition, using water table related hydrological processes as a proxy for water quality

  9. Biogeophysical impacts of peatland forestation on regional climate changes in Finland

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Markkanen, T.; Backman, L.; Henttonen, H. M.; Pietikäinen, J.-P.; Mäkelä, H. M.; Laaksonen, A.

    2014-12-01

    Land cover changes can impact the climate by influencing the surface energy and water balance. Naturally treeless or sparsely treed peatlands were extensively drained to stimulate forest growth in Finland over the second half of 20th century. The aim of this study is to investigate the biogeophysical effects of peatland forestation on regional climate in Finland. Two sets of 18-year climate simulations were done with the regional climate model REMO by using land cover data based on pre-drainage (1920s) and post-drainage (2000s) Finnish national forest inventories. In the most intensive peatland forestation area, located in the middle west of Finland, the results show a warming in April of up to 0.43 K in monthly-averaged daily mean 2 m air temperature, whereas a slight cooling from May to October of less than 0.1 K in general is found. Consequently, snow clearance days over that area are advanced up to 5 days in the mean of 15 years. No clear signal is found for precipitation. Through analysing the simulated temperature and energy balance terms, as well as snow depth over five selected subregions, a positive feedback induced by peatland forestation is found between decreased surface albedo and increased surface air temperature in the snow-melting period. Our modelled results show good qualitative agreements with the observational data. In general, decreased surface albedo in the snow-melting period and increased evapotranspiration in the growing period are the most important biogeophysical aspects induced by peatland forestation that cause changes in climate. The results from this study can be further integrally analysed with biogeochemical effects of peatland forestation to provide background information for adapting future forest management to mitigate climate warming effects. Moreover, they provide insights about the impacts of projected forestation of tundra at high latitudes due to climate change.

  10. Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export.

    PubMed

    Olefeldt, David; Roulet, Nigel T

    2014-10-01

    Permafrost thaw in peatlands has the potential to alter catchment export of dissolved organic carbon (DOC) and thus influence downstream aquatic C cycling. Subarctic peatlands are often mosaics of different peatland types, where permafrost conditions regulate the hydrological setting of each type. We show that hydrological setting is key to observed differences in magnitude, timing, and chemical composition of DOC export between permafrost and nonpermafrost peatland types, and that these differences influence the export of DOC of larger catchments even when peatlands are minor catchment components. In many aspects, DOC export from a studied peatland permafrost plateau was similar to that of a forested upland catchment. Similarities included low annual export (2-3 g C m(-2) ) dominated by the snow melt period (~70%), and how substantial DOC export following storms required wet antecedent conditions. Conversely, nonpermafrost fens had higher DOC export (7 g C m(-2) ), resulting from sustained hydrological connectivity during summer. Chemical composition of catchment DOC export arose from the mixing of highly aromatic DOC from organic soils from permafrost plateau soil water and upland forest surface horizons with nonaromatic DOC from mineral soil groundwater, but was further modulated by fens. Increasing aromaticity from fen inflow to outlet was substantial and depended on both water residence time and water temperature. The role of fens as catchment biogeochemical hotspots was further emphasized by their capacity for sulfate retention. As a result of fen characteristics, a 4% fen cover in a mixed catchment was responsible for 34% higher DOC export, 50% higher DOC concentrations and ~10% higher DOC aromaticity at the catchment outlet during summer compared to a nonpeatland upland catchment. Expansion of fens due to thaw thus has potential to influence landscape C cycling by increasing fen capacity to act as biogeochemical hotspots, amplifying aquatic C cycling, and

  11. Environmental correlates of peatland carbon fluxes in a thawing landscape: do transitional thaw stages matter?

    NASA Astrophysics Data System (ADS)

    Malhotra, A.; Roulet, N. T.

    2015-01-01

    Peatlands in discontinuous permafrost regions occur as a mosaic of wetland types, each with variable sensitivity to climate change. Permafrost thaw further increases the spatial heterogeneity in ecosystem structure and function in peatlands. Carbon (C) fluxes are well characterized in end-member thaw stages such as fully intact or fully thawed permafrost but remain unconstrained for transitional stages that cover a significant area of thawing peatlands. Furthermore, changes in the environmental correlates of C fluxes, due to thaw are not well described: a requirement for modeling future changes to C storage of permafrost peatlands. We investigated C fluxes and their correlates in end-member and a number of transitional thaw stages in a sub-arctic peatland. Across peatland lumped CH4 and CO2 flux data had significant correlations with expected correlates such as water table depth, thaw depth, temperature, photosynthetically active radiation and vascular green area. Within individual thaw states, bivariate correlations as well as multiple regressions between C flux and environmental factors changed variably with increasing thaw. The variability in directions and magnitudes of correlates reflects the range of structural conditions that could be present along a thaw gradient. These structural changes correspond to changes in C flux controls, such as temperature and moisture, and their interactions. Temperature sensitivity of CH4 increased with increasing thaw in bivariate analyses, but lack of this trend in multiple regression analyses suggested cofounding effects of substrate or water limitation on the apparent temperature sensitivity. Our results emphasize the importance of incorporating transitional stages of thaw in landscape level C budgets and highlight that end-member or adjacent thaw stages do not adequately describe the variability in structure-function relationships present along a thaw gradient.

  12. Environmental correlates of peatland carbon fluxes in a thawing landscape: do transitional thaw stages matter?

    NASA Astrophysics Data System (ADS)

    Malhotra, A.; Roulet, N. T.

    2015-05-01

    Peatlands in discontinuous permafrost regions occur as a mosaic of wetland types, each with variable sensitivity to climate change. Permafrost thaw further increases the spatial heterogeneity in ecosystem structure and function in peatlands. Carbon (C) fluxes are well characterized in end-member thaw stages such as fully intact or fully thawed permafrost but remain unconstrained for transitional stages that cover a significant area of thawing peatlands. Furthermore, changes in the environmental correlates of C fluxes, due to thaw, are not well described - a requirement for modeling future changes to C storage of permafrost peatlands. We investigated C fluxes and their correlates in end-member and a number of transitional thaw stages in a sub-arctic peatland. Across peatland-lumped CH4 and CO2 flux data had significant correlations with expected correlates such as water table depth, thaw depth, temperature, photosynthetically active radiation and vascular green area. Within individual thaw states, bivariate correlations as well as multiple regressions between C flux and environmental factors changed variably with increasing thaw. The variability in directions and magnitudes of correlates reflects the range of structural conditions that could be present along a thaw gradient. These structural changes correspond to changes in C flux controls, such as temperature and moisture, and their interactions. Temperature sensitivity of CH4 increased with increasing thaw in bivariate analyses, but lack of this trend in multiple regression analyses suggested cofounding effects of substrate or water limitation on the apparent temperature sensitivity. Our results emphasize the importance of incorporating transitional stages of thaw in landscape level C budgets and highlight that end-member or adjacent thaw stages do not adequately describe the variability in structure-function relationships present along a thaw gradient.

  13. Disappearance of Relict Permafrost in Boreal North America: Effects on Peatland Carbon Storage and Fluxes

    SciTech Connect

    Turetsky, M. R.; Wieder, R. K.; Vitt, D. H.; Evans, R. J.; Scott, K. D.

    2007-01-01

    Boreal peatlands in Canada have harbored relict permafrost since the Little Ice Age due to the strong insulating properties of peat. Ongoing climate change has triggered widespread degradation of localized permafrost in peatlands across continental Canada. Here, we explore the influence of differing permafrost regimes (bogs with no surface permafrost, localized permafrost features with surface permafrost, and internal lawns representing areas of permafrost degradation) on rates of peat accumulation at the southernmost limit of permafrost in continental Canada. Net organic matter accumulation generally was greater in unfrozen bogs and internal lawns than in the permafrost landforms, suggesting that surface permafrost inhibits peat accumulation and that degradation of surface permafrost stimulates net carbon storage in peatlands. To determine whether differences in substrate quality across permafrost regimes control trace gas emissions to the atmosphere, we used a reciprocal transplant study to experimentally evaluate environmental versus substrate controls on carbon emissions from bog, internal lawn, and permafrost peat. Emissions of CO{sub 2} were highest from peat incubated in the localized permafrost feature, suggesting that slow organic matter accumulation rates are due, at least in part, to rapid decomposition in surface permafrost peat. Emissions of CH{sub 4} were greatest from peat incubated in the internal lawn, regardless of peat type. Localized permafrost features in peatlands represent relict surface permafrost in disequilibrium with the current climate of boreal North America, and therefore are extremely sensitive to ongoing and future climate change. Our results suggest that the loss of surface permafrost in peatlands increases net carbon storage as peat, though in terms of radiative forcing, increased CH{sub 4} emissions to the atmosphere will partially or even completely offset this enhanced peatland carbon sink for at least 70 years following

  14. Impacts of drain blocking on the aquatic carbon export from a UK peatland

    NASA Astrophysics Data System (ADS)

    Leith, Fraser; Dinsmore, Kerry; Carfrae, Jennifer

    2016-04-01

    Drainage ditches, which have historically been used across UK peatlands, provide a rapid pathway for carbon export between terrestrial and aquatic systems, potentially reducing or reversing the net uptake of carbon by peatlands. Currently, considerable investment is being made in Scotland to restore drained peatlands with the aim of raising water tables, restoring active vegetation cover, enhancing carbon uptake and reducing carbon losses via the aquatic pathway. However, monitoring of restoration and its impact is often restricted by a lack of pre-restoration data and typically does not cover the full range of fluvial carbon species. Drain blocking was carried out in March 2015 at the Auchencorth Moss peatland, SE Scotland, which has an extensive record of fluvial carbon measurements (from 2007 to present day). This study combines an intensive 12 month field monitoring campaign, during and after drain blocking works, with the long-term record to investigate the impacts of drain blocking on the dissolved and gaseous carbon export via the aquatic pathway. Post-restoration, concentrations and fluxes of all stream water dissolved and gaseous carbon species were in the range of values measured over the period 2007 to present; with no significant change in the 12 months post-restoration. The results from this study indicate that the drain blocking works did not have a significant impact on the concentration or speciation of carbon exported via the aquatic pathway which can be attributed to the largely overgrown nature of the drains and the large inter- and intra-annual variability in the system. This study raises questions on the suitability of some peatlands for drain blocking and the pre- and post-restoration monitoring required to accurately assess the impacts of peatland restoration activities.

  15. Effect of vegetation removal and water table drawdown on the non-methane biogenic volatile organic compound emissions in boreal peatland microcosms

    NASA Astrophysics Data System (ADS)

    Faubert, Patrick; Tiiva, Päivi; Rinnan, Åsmund; Räty, Sanna; Holopainen, Jarmo K.; Holopainen, Toini; Rinnan, Riikka

    2010-11-01

    Biogenic volatile organic compound (BVOC) emissions are important in the global atmospheric chemistry and their feedbacks to global warming are uncertain. Global warming is expected to trigger vegetation changes and water table drawdown in boreal peatlands, such changes have only been investigated on isoprene emission but never on other BVOCs. We aimed at distinguishing the BVOCs released from vascular plants, mosses and peat in hummocks (dry microsites) and hollows (wet microsites) of boreal peatland microcosms maintained in growth chambers. We also assessed the effect of water table drawdown (-20 cm) on the BVOC emissions in hollow microcosms. BVOC emissions were measured from peat samples underneath the moss surface after the 7-week-long experiment to investigate whether the potential effects of vegetation and water table drawdown were shown. BVOCs were sampled using a conventional chamber method, collected on adsorbent and analyzed with GC-MS. In hummock microcosms, vascular plants increased the monoterpene emissions compared with the treatment where all above-ground vegetation was removed while no effect was detected on the sesquiterpenes, other reactive VOCs (ORVOCs) and other VOCs. Peat layer from underneath the surface with intact vegetation had the highest sesquiterpene emissions. In hollow microcosms, intact vegetation had the highest sesquiterpene emissions. Water table drawdown decreased monoterpene and other VOC emissions. Specific compounds could be closely associated to the natural/lowered water tables. Peat layer from underneath the surface of hollows with intact vegetation had the highest emissions of monoterpenes, sesquiterpenes and ORVOCs whereas water table drawdown decreased those emissions. The results suggest that global warming would change the BVOC emission mixtures from boreal peatlands following changes in vegetation composition and water table drawdown.

  16. National Indian Education Study--Part II: The Educational Experiences of American Indian and Alaska Native Students in Grades 4 and 8. Statistical Analysis Report. NCES 2010-463

    ERIC Educational Resources Information Center

    Mead, N.; Grigg, W.; Moran, R.; Kuang, M.

    2010-01-01

    Since 2005, the National Indian Education Study (NIES) has provided educators, policymakers, and the public with information about the background and academic performance of fourth- and eighth-grade American Indian and Alaska Native (AI/AN) students in the United States. This report, the second in a two-part series based on the 2009 NIES survey,…

  17. Aquatic carbon export from peatland catchments recently undergone wind farm development

    NASA Astrophysics Data System (ADS)

    Smith, Ben; Waldron, Susan; Henderson, Andrew; Flowers, Hugh; Gilvear, David

    2013-04-01

    Scotland's peat landscapes are desirable locations for wind-based renewables due to high wind resources and low land use pressures in these areas. The environmental impact of sitting wind-based renewables on peats however, is unknown. Globally, peatlands are important terrestrial carbon stores. Given the topical nature of carbon-related issues, e.g. global warming and carbon footprints, it is imperative we help mitigate their degradation and maintain carbon sequestration. To do so, we need to better understand how peatland systems function with regards to their carbon balance (export versus sequestration) so we can assess their resilience and adaptation to hosting land-based renewable energy projects. Predicting carbon lost as a result of construction of wind farms built on peatland has not been fully characterised and this research will provide data that can supplement current 'carbon payback calculator' models for wind farms that aim to reinforce their 'green' credentials. Transfer of carbon from the terrestrial peatland systems to the aquatic freshwater and oceanic systems is most predominant during periods of high rainfall. It has been estimated that 50% of carbon is exported during only 10% of highest river flows, (Hinton et al., 1998). Furthermore, carbon export from peatlands is known to have a seasonal aspect with highest concentrations of dissolved organic carbon (DOC) found mostly in late summer months of August and September and lowest in December and January, (Dawson et al., 2004). Event sampling, where high intensity sample collection is carried out during high river flow periods, offers a better insight, understanding and estimation of carbon aquatic fluxes from peatland landscapes. The Gordonbush estate, near Brora, has an extensive peatland area where a wind farm development has recently been completed (April 2012). Investigations of aquatic carbon fluxes from this peatland system were started in July 2010, in conjunction with the start of

  18. A multi-tracer approach to determine groundwater discharge patterns in pristine peatlands

    NASA Astrophysics Data System (ADS)

    Isokangas, Elina; Rossi, Pekka; Kløve, Bjørn

    2014-05-01

    Changes in water flow patterns (e.g. due to ditching or pumping water) in the vicinity of a peatland can affect its hydrology and ecology irreversibly. In Finland esker aquifers, often used for water abstraction, discharge groundwater typically to peatlands. Locations of these discharge zones are important for understanding peatland hydrology and ecology in general and for predicting the impacts of groundwater abstraction. In this study, a Finnish pristine peatland connected to an esker aquifer was sampled for natural tracers (stable water isotopes, electrical conductivity and temperature, n = 55) from two depths (30 cm and under the peat layer) in the summer of 2013. The peat levels of the sampling points varied between 0.57 - 1.00 m. In addition, hydraulic conductivity measurements (n = 13) and airborne thermal imaging were carried out and local precipitation was sampled for stable water isotopes. The CRDS-method (Picarro L2120-i analyzer) was applied to analyze δ18O and δ2H values. Local Meteoric Water Line (LMWL) was determined using precipitation from Nuoritta (17 km west from the study site), δ2H = 7.24 δ18O + 7.94 (R2 = 0.996). Ranges for δ18O and δ2H of peatland water were, -13.3 o - -10.3 o and -96.1 o - -75.6 o respectively. Furthermore, electrical conductivity varied between 19.6 - 192.8 mS m-1, hydraulic conductivity between 1.7×10-8 - 5.0×10-4 m s-1 and temperature between 6.1 - 16.8 ° C. Natural tracers were used for identifying water flow patterns of the peatland. Interpretation of the results was complicated due to a stream flowing through the studied peatland. However, groundwater discharge zones were observed alongside the esker and also further away from the esker in the peatland area. This research shows that combination of high-resolution thermal images and discrete field measurements will result in more reliable and precise water flow patterns.

  19. Drivers of Holocene peatland carbon accumulation across a climate gradient in northeastern North America

    NASA Astrophysics Data System (ADS)

    Charman, Dan J.; Amesbury, Matthew J.; Hinchliffe, William; Hughes, Paul D. M.; Mallon, Gunnar; Blake, William H.; Daley, Tim J.; Gallego-Sala, Angela V.; Mauquoy, Dmitri

    2015-08-01

    Peatlands are an important component of the Holocene global carbon (C) cycle and the rate of C sequestration and storage is driven by the balance between net primary productivity and decay. A number of studies now suggest that climate is a key driver of peatland C accumulation at large spatial scales and over long timescales, with warmer conditions associated with higher rates of C accumulation. However, other factors are also likely to play a significant role in determining local carbon accumulation rates and these may modify past, present and future peatland carbon sequestration. Here, we test the importance of climate as a driver of C accumulation, compared with hydrological change, fire, nitrogen content and vegetation type, from records of C accumulation at three sites in northeastern North America, across the N-S climate gradient of raised bog distribution. Radiocarbon age models, bulk density values and %C measurements from each site are used to construct C accumulation histories commencing between 11,200 and 8000 cal. years BP. The relationship between C accumulation and environmental variables (past water table depth, fire, peat forming vegetation and nitrogen content) is assessed with linear and multivariate regression analyses. Differences in long-term rates of carbon accumulation between sites support the contention that a warmer climate with longer growing seasons results in faster rates of long-term carbon accumulation. However, mid-late Holocene accumulation rates show divergent trends, decreasing in the north but rising in the south. We hypothesise that sites close to the moisture threshold for raised bog distribution increased their growth rate in response to a cooler climate with lower evapotranspiration in the late Holocene, but net primary productivity declined over the same period in northern areas causing a decrease in C accumulation. There was no clear relationship between C accumulation and hydrological change, vegetation, nitrogen content

  20. Plant phenology and composition controls of carbon fluxes in a boreal peatland

    NASA Astrophysics Data System (ADS)

    Peichl, Matthias; Gažovič, Michal; Vermeij, Ilse; De Goede, Eefje; Sonnentag, Oliver; Limpens, Juul; Nilsson, Mats B.

    2016-04-01

    Vegetation drives the peatland carbon (C) cycle via the processes of photosynthesis, plant respiration and decomposition as well as by providing substrate for methane (CH4) and dissolved organic carbon production. However, due to the lack of comprehensive vegetation data, variations in the peatland C fluxes are commonly related to temperature and other more easily measured abiotic (i.e. weather and soil) variables. Due to the temporal co-linearity between plant development and abiotic variables, these relationships may describe the variations in C fluxes reasonably well, however, without representing the true mechanistic processes driving the peatland C cycle. As a consequence, current process-based models are poorly parameterized and unable to adequately predict the responses of the peatland C cycle to climate change, extreme events and anthropogenic impacts. To fill this knowledge gap, we explored vegetation phenology and composition effects on the peatland C cycle at the Degerö peatland located in northern Sweden. We used a greenness index derived from digital repeat photography to quantitatively describe plant canopy development with high temporal (i.e. daily) and spatial (plot to ecosystem) resolution. In addition, eddy covariance and static chamber measurements of carbon dioxide (CO2) and CH4 fluxes over an array of vegetation manipulation plots were conducted over multiple years. Our results suggest that vascular plant phenology controls the onset and pattern of eddy covariance-derived gross primary production (GPP) during the spring period, while abiotic conditions modify GPP during the summer period when plant canopy cover is fully developed. Inter-annual variations in the spring onset and patterns of plant canopy development were best explained by differences in the preceding growing degree day sum. We also observed strong correlations of canopy greenness with the net ecosystem CO2 exchange and ecosystem respiration. On average, vascular plant and moss

  1. Organic Matter Quality and its Influence on Carbon Turnover and Stabilization in Northern Peatlands

    NASA Astrophysics Data System (ADS)

    Turetsky, M. R.; Wieder, R. K.

    2002-12-01

    Peatlands cover 3-5 % of the world's ice-free land area, but store about 33 % of global terrestrial soil carbon. Peat accumulation in northern regions generally is controlled by slow decomposition, which may be limited by cold temperatures and water-logging. Poor organic matter quality also may limit decay, and microbial activity in peatlands likely is regulated by the availability of labile carbon and/or nutrients. Conversely, carbon in recalcitrant soil structures may be chemically protected from microbial decay, particularly in peatlands where carbon can be buried in anaerobic soils. Soil organic matter quality is controlled by plant litter chemical composition and the susceptibility of organic compounds to decomposition through time. There are a number of techniques available for characterizing organic quality, ranging from chemical proximate or elemental analysis to more qualitative methods such as nuclear magenetic resonance, pyrolysis/mass spectroscopy, and Fourier transform infrared spectroscopy. We generally have relied on proximate analysis for quantitative determination of several organic fractions (i.e., water-soluble carbohydrates, soluble nonpolars, water-soluble phenolics, holocellulose, and acid insoluble material). Our approaches to studying organic matter quality in relation to C turnover in peatlands include 1) 14C labelling of peatland vegetation along a latitudinal gradient in North America, allowing us to follow the fate of 14C tracer in belowground organic fractions under varying climates, 2) litter bag studies focusing on the role of individual moss species in litter quality and organic matter decomposition, and 3) laboratory incubations of peat to explore relationships between organic matter quality and decay. These studies suggest that proximate organic fractions vary in lability, but that turnover of organic matter is influenced both by plant species and climate. Across boreal peatlands, measures of soil recalcitrance such as acid

  2. Carbon isotopic composition of deep carbon gases in an ombrogenous peatland, northwestern Ontario, Canada

    SciTech Connect

    Aravena, R. . Center for Groundwater Research and Wetlands Research Center); Warner, B.G. . Wetlands Research Center and Dept. of Geography); Charman, D.J. . Dept. of Geographical Sciences); Belyea, L.R. . School of Biological Sciences); Mathur, S.P. ); Dinel, H. )

    1993-01-01

    Radiocarbon dating and carbon isotope analyses of deep peat and gases in a small ombrogenous peatland in northwestern Ontario reveals the presence of old gases at depth that are 1000-2000 yr younger than the enclosing peat. The authors suggest that the most likely explanation to account for this age discrepancy is the downward movement by advection of younger dissolved organic carbon for use by fermentation and methanogens bacteria. This study identifies a potentially large supply of old carbon gases in peatlands that should be considered in global carbon models of the terrestrial biosphere.

  3. Alaska Interagency Ecosystem Health Work Group

    USGS Publications Warehouse

    Shasby, Mark

    2009-01-01

    The Alaska Interagency Ecosystem Health Work Group is a community of practice that recognizes the interconnections between the health of ecosystems, wildlife, and humans and meets to facilitate the exchange of ideas, data, and research opportunities. Membership includes the Alaska Native Tribal Health Consortium, U.S. Geological Survey, Alaska Department of Environmental Conservation, Alaska Department of Health and Social Services, Centers for Disease Control and Prevention, U.S. Fish and Wildlife Service, Alaska Sea Life Center, U.S. Environmental Protection Agency, and Alaska Department of Fish and Game.

  4. Alaska Athabascan stellar astronomy

    NASA Astrophysics Data System (ADS)

    Cannon, Christopher M.

    Stellar astronomy is a fundamental component of Alaska Athabascan cultures that facilitates time-reckoning, navigation, weather forecasting, and cosmology. Evidence from the linguistic record suggests that a group of stars corresponding to the Big Dipper is the only widely attested constellation across the Northern Athabascan languages. However, instruction from expert Athabascan consultants shows that the correlation of these names with the Big Dipper is only partial. In Alaska Gwich'in, Ahtna, and Upper Tanana languages the Big Dipper is identified as one part of a much larger circumpolar humanoid constellation that spans more than 133 degrees across the sky. The Big Dipper is identified as a tail, while the other remaining asterisms within the humanoid constellation are named using other body part terms. The concept of a whole-sky humanoid constellation provides a single unifying system for mapping the night sky, and the reliance on body-part metaphors renders the system highly mnemonic. By recognizing one part of the constellation the stargazer is immediately able to identify the remaining parts based on an existing mental map of the human body. The circumpolar position of a whole-sky constellation yields a highly functional system that facilitates both navigation and time-reckoning in the subarctic. Northern Athabascan astronomy is not only much richer than previously described; it also provides evidence for a completely novel and previously undocumented way of conceptualizing the sky---one that is unique to the subarctic and uniquely adapted to northern cultures. The concept of a large humanoid constellation may be widespread across the entire subarctic and have great antiquity. In addition, the use of cognate body part terms describing asterisms within humanoid constellations is similarly found in Navajo, suggesting a common ancestor from which Northern and Southern Athabascan stellar naming strategies derived.

  5. Operation IceBridge Alaska

    NASA Astrophysics Data System (ADS)

    Larsen, C.

    2015-12-01

    The University of Alaska Fairbanks (UAF) has flown LiDAR missions for Operation IceBridge in Alaska each year since 2009, expanding upon UAF's airborne laser altimetry program which started in 1994. These observations show that Alaska's regional mass balance is -75+11/-16 Gt yr-1 (1994-2013) (Larsen et al., 2015). A surprising result is that the rate of surface mass loss observed on non-tidewater glaciers in Alaska is extremely high. At these rates, Alaska contributes ~1 mm to global sea level rise every 5 years. Given the present lack of adequate satellite resources, Operation IceBridge airborne surveys by UAF are the most effective and efficient method to monitor this region's impact on global sea level rise. Ice depth measurements using radar sounding have been part of these airborne surveys since 2012. Many of Alaska's tidewater glaciers are bedded significantly below sea level. The depth and extent of glacier beds below sea level are critical factors in the dynamics of tidewater retreat. Improved radar processing tools are being used to predict clutter using forward simulation. This is essential to properly sort out true bed returns, which are often masked or obscured by valley wall returns. This presentation will provide an overview of the program, highlighting recent findings and observations from the most recent campaigns, and focusing on techniques used for the extrapolation of surface elevation changes to regional mass balances.

  6. Vegetation History of Pleasant Island, Southeastern Alaska, since 13,000 yr B.P.

    NASA Astrophysics Data System (ADS)

    Hansen, Barbara C. S.; Engstrom, Daniel R.

    1996-09-01

    A 13,000-year history of late-Quaternary vegetational and climatic change has been derived from lacustrine sediments from Pleasant Island in the Glacier Bay region of southeastern Alaska. Early arrival of lodgepole pine and mountain hemlock, indicated by the presence of pollen and conifer stomata, suggests expansion from refugia in the Alexander Archipelago. A short-term climatic reversal, possibly correlated with the European Younger Dryas, is inferred from the expansion of tundra elements and deposition of inorganic sediments between 10,600 and 9900 14C yr B.P. Two peat cores from the lake catchment verify Holocene vegetation changes and aid in the separation of biogenic from climatic forces affecting vegetation history. Differences in pollen representation among the three cores illustrate the variation among pollen-collecting substrates, as well as the spatial heterogeneity of peatland development and its dependence on local hydrology. Initial peat accumulation and soil paludification, occasioned by increases in temperature and precipitation in the early Holocene, allowed western and mountain hemlock to replace sitka spruce 8500-8000 yr B. P. Open muskeg became widespread about 7000 yr B. P. and allowed lodgepole pine to reinvade the region after a 2000-yr absence. The extensive replacement of fen elements by bog taxa at 3400 yr B. P. suggests increased paludification due to changing hydrologic conditions; its correlation with the upland expansion of Tsuga heterophyllasuggests the onset of a cooler/wetter Neoglacial climate in southeastern Alaska.

  7. Fire in the Vegetation and Peatlands of Borneo, 1997-2007: Patterns, Drivers and Emissions from Biomass Burning

    NASA Astrophysics Data System (ADS)

    Spessa, Allan; Weber, Ulrich; Langner, Andreas; Siegert, Florian; Heil, Angelika

    2010-05-01

    correlations are noticeably much weaker or absent in Sarawak and Sabah, and central Borneo, where little or no deforestation was observed. Emissions from biomass burning reflect fire activity, and that fires in the carbon-rich peats of southern Kalimantan dominate the emissions profile during the El Nino years of 1997-98, 2002, 2004 and 2006. Previous work in southern Amazon forests demonstrates that recurrent fires promote a change from tree-dominated to grass-dominated ecosystems which, in turn, promotes even more fires. We show that recurrent fire and deforestation are also linked as part of a similar positive feedback process in Kalimantan. Our results support the detailed field work undertaken in 1997-98 in East Kalimantan, and reinforce these findings across time and space. Emissions from fires in Kalimantan peatlands represent a serious perturbation in terms of forcing from trace gases and aerosols on regional and global climate. Several global and regional climate modelling studies have reported that equatorial SE Asia, including Borneo, will experience reduced rainfall in future decades. At the same time, demands for establishing pulp paper and palm oil plantations to replace native rainforests, especially on peatlands where tenure conflicts among land owners tend to be minimal, is forecast to increase. These joint scenarios imply even more fires and emissions in future. It is critical therefore that present efforts to mitigate emissions through reduced deforestation programs in the region works, otherwise the consequences will be disastrous.

  8. Understanding the Impact of Land Management on Carbon Losses from Peatlands

    NASA Astrophysics Data System (ADS)

    Savage, A.; Holden, J.; Wainwright, J.

    2010-05-01

    British peatlands have historically been managed in many different ways to provide an income for rural communities. Such practices involve heather burning on grouse shooting estates, sheep grazing, drainage to increase the area of land available for agriculture and afforestation. Carbon budget calculations for unmanaged peatlands have demonstrated that peatlands are carbon sinks. At present, little is known about how management affects carbon stocks, and whether one strategy might be favoured over another in the future, from a carbon stock preservation perspective. As the need to safeguard carbon stocks rises up the political agenda, questions are being asked about how peatlands should be managed to limit carbon losses. Carbon cycling in peat is governed by four drivers (Laiho, 2006), environmental conditions (e.g. temperature, water table level), substrate quality (e.g. how recalcitrant the peat is), nutrients (e.g. nitrogen required to synthesis the carbon stocks) and microbial community (e.g. are the microbes present able to utilise the available substrate). Changes in one or more of these drivers will influence the carbon budget of a peatland. How land management influences these drivers is unclear at present. Carbon budget calculations carried out by Worrall et al. (2003 and 2009) indicate that carbon dioxide and dissolved organic carbon (DOC) account for the greatest losses of carbon from peatland systems. If climate change predictions are realised, peatlands are expected to become sources of carbon as rising temperatures and falling water tables will result in increased rates of carbon mineralisation and subsequent losses of carbon. By investigating the influence of land management on these key carbon loss pathways, more accurate predictions of the effects of climate change on UK peatlands can be made. A field study was carried out in the British uplands to determine how carbon losses vary between differently managed peatlands, and to identify some of the

  9. The peatlands developing history in the Sanjiang Plain, NE China, and its response to East Asian monsoon variation.

    PubMed

    Zhang, Zhenqing; Xing, Wei; Wang, Guoping; Tong, Shouzheng; Lv, Xianguo; Sun, Jimin

    2015-01-01

    Studying the peatlands accumulation and carbon (C) storage in monsoonal areas could provide useful insights into the response of C dynamics to climate variation in the geological past. Here, we integrated 40 well-dated peat/lake sediment cores to reveal the peatlands evolution history in the Sanjiang Plain and examine its links to East Asian monsoon variations during the Holocene. The results show that 80% peatlands in the Sanjiang Plain initiated after 4.7 ka (1 ka = 1000 cal yr BP), with the largest initiating frequency around 4.5 ka. The mean C accumulation rate of peatlands in the Sanjiang Plain exhibits a synchronous increase with the peatlands expansion during the Holocene. Such a peatlands expanding and C accumulating pattern corresponds well to the remarkable drying event subsequent to the Holocene monsoon maximum. We suggest that in addition to the locally topographic conditions, Holocene variations of East Asian summer monsoon (especially its associated precipitation) have played a critical role in driving the peatlands initiation and expansion in the Sanjiang Plain. PMID:26076653

  10. Effects of experimental warming and elevated CO2 on surface methane and CO­2 fluxes from a boreal black spruce peatland

    NASA Astrophysics Data System (ADS)

    Gill, A. L.; Finzi, A.; Giasson, M. A.

    2015-12-01

    High latitude peatlands represent a major terrestrial carbon store sensitive to climate change, as well as a globally significant methane source. While elevated atmospheric carbon dioxide concentrations and warming temperatures may increase peat respiration and C losses to the atmosphere, reductions in peatland water tables associated with increased growing season evapotranspiration may alter the nature of trace gas emission and increase peat C losses as CO2 relative to methane (CH4). As CH4 is a greenhouse gas with twenty times the warming potential of CO2, it is critical to understand how surface fluxes of CO2 and CH4 will be influenced by factors associated with global climate change. We used automated soil respiration chambers to assess the influence of elevated atmospheric CO2 and whole ecosystem warming on peatland CH4 and CO2 fluxes at the SPRUCE (Spruce and Peatland Responses Under Climatic and Environmental Change) Experiment in northern Minnesota. Belowground warming treatments were initiated in July 2014 and whole ecosystem warming and elevated CO2 treatments began in August 2015. Here we report soil iCO2 and iCH4 flux responses to the first year of belowground warming and the first two months of whole ecosystem manipulation. We also leverage the spatial and temporal density of measurements across the twenty autochambers to assess how physical (i.e., plant species composition, microtopography) and environmental (i.e., peat temperature, water table position, oxygen availability) factors influence observed rates of CH4 and CO2 loss. We find that methane fluxes increased significantly across warming treatments following the first year of belowground warming, while belowground warming alone had little influence on soil CO2 fluxes. Peat microtopography strongly influenced trace gas emission rates, with higher CH4 fluxes in hollow locations and higher CO2 fluxes in hummock locations. While there was no difference in the isotopic composition of the methane

  11. Improving Student Achievement in Alaska. Alaska Goals 2000 Annual Report, 1997-98.

    ERIC Educational Resources Information Center

    Alaska State Dept. of Education, Juneau.

    Alaska Goals 2000 is part of a coordinated, statewide effort to improve public education for all students in Alaska. In 1997-1998, 90% of Alaska's federal funding was used to fund grants to local school districts, and 10% was used to fund state-level activities through the Alaska Department of Education. During 1997-1998, curriculum frameworks and…

  12. 78 FR 73144 - Subsistence Management Program for Public Lands in Alaska; Western Interior Alaska Federal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-05

    ... Subsistence Management Program for Public Lands in Alaska; Western Interior Alaska Federal Subsistence... subsistence uses on Federal public lands and waters in Alaska. The Federal Subsistence Board, which includes... the subsistence management of fish and wildlife on Federal public lands in Alaska. The Board...

  13. Alaska's Children, 1998. Alaska Head Start State Collaboration Project, Quarterly Report.

    ERIC Educational Resources Information Center

    Douglas, Dorothy, Ed.

    1998-01-01

    This document consists of four issues of the quarterly report "Alaska's Children," which provides information on the Alaska Head Start State Collaboration Project and updates on Head Start activities in Alaska. Regular features in the issues include a calendar of conferences and meetings, a status report on Alaska's children, reports from the…

  14. Alaska GeoFORCE, A New Geologic Adventure in Alaska

    NASA Astrophysics Data System (ADS)

    Wartes, D.

    2011-12-01

    RAHI, the Rural Alaska Honors Institute is a statewide, six-week, summer college-preparatory bridge program at the University of Alaska Fairbanks for Alaska Native and rural high school juniors and seniors. A program of rigorous academic activity combines with social, cultural, and recreational activities. Students are purposely stretched beyond their comfort levels academically and socially to prepare for the big step from home or village to a large culturally western urban campus. This summer RAHI is launching a new program, GeoFORCE Alaska. This outreach initiative is designed to increase the number and diversity of students pursuing STEM degree programs and entering the future high-tech workforce. It uses Earth science as the hook because most kids get excited about dinosaurs, volcanoes and earthquakes, but it includes physics, chemistry, math, biology and other sciences. Students will be recruited, initially from the Arctic North Slope schools, in the 8th grade to begin the annual program of approximately 8 days, the summer before their 9th grade year and then remain in the program for all four years of high school. They must maintain a B or better grade average and participate in all GeoFORCE events. The carrot on the end of the stick is an exciting field event each summer. Over the four-year period, events will include trips to Fairbanks, Arizona, Oregon and the Appalachians. All trips are focused on Earth science and include a 100+ page guidebook, with tests every night culminating with a final exam. GeoFORCE Alaska is being launched by UAF in partnership with the University of Texas at Austin, which has had tremendous success with GeoFORCE Texas. GeoFORCE Alaska will be managed by UAF's long-standing Rural Alaska Honors Insitute (RAHI) that has been successfully providing intense STEM educational opportunities for Alaskan high school students for almost 30 years. The Texas program, with adjustments for differences in culture and environment, will be

  15. 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.

  16. Profile: American Indian/Alaska Native

    MedlinePlus

    ... million American Indians and Alaska Natives. Typically, this urban clientele has less accessibility to hospitals; health clinics ... IHS and tribal health programs. Studies on the urban American Indian and Alaska Native population have documented ...

  17. 76 FR 53151 - Alaska Native Claims Selection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-25

    ... Kuskokwim Corporation, Successor in Interest to Red Devil Incorporated. The decision approves the surface... Devil, Alaska, and are located in: Seward Meridian, Alaska T. 22 N., R. 44 W., Secs. 27 to 34,...

  18. Mercury sequestration in forests and peatlands: a review.

    PubMed

    Grigal, D F

    2003-01-01

    Nearly all Hg in vegetation is derived directly from the atmosphere. Mass of Hg in forest vegetation (roughly 0.1 mg m(-2)) is about an order of magnitude smaller than that in the forest floor (1 mg m(-2)) and two orders of magnitude smaller than that in the mineral soil (10 mg m(-2)). Mass of Hg in peat (20 mg m(-2)) is greater than the sum of that in mineral soil and the forest floor; wetlands usually sequester more Hg than associated uplands. The strong relationship of Hg to organic matter, associated with binding by reduced S groups, is fundamental to understanding Hg distribution and behavior in terrestrial systems. The stoichiometry of the Hg-C relationship varies; Hg-S relationships, though less variable, are not constant. Because of the Hg-organic matter link, landscape conditions that lead to differential soil organic matter accumulation are likely to lead to differential Hg accumulation. The ratio of methylmercury (MeHg) to total Hg is generally low in both vegetation (near 1.5%) and soil (<1%), but areas of poorly drained soils and wetlands are sites of MeHg production. The annual emission of anthropic Hg from the 48 contiguous states of the USA (144 Mg) is two orders of magnitude less than the pool of Hg in forests of those states (30,300 Mg). Peatlands, less than 2% of total land area, sequester more than 20 times annual emissions (2930 Mg). If global climate change affects C storage it will indirectly affect Hg storage, having a major effect on the balance between emissions and sequestration and on the global Hg cycle. PMID:12708661

  19. Remotely sensed evidence of tropical peatland conversion to oil palm.

    PubMed

    Koh, Lian Pin; Miettinen, Jukka; Liew, Soo Chin; Ghazoul, Jaboury

    2011-03-22

    Rising global demands for food and biofuels are driving forest clearance in the tropics. Oil-palm expansion contributes to biodiversity declines and carbon emissions in Southeast Asia. However, the magnitudes of these impacts remain largely unquantified until now. We produce a 250-m spatial resolution map of closed canopy oil-palm plantations in the lowlands of Peninsular Malaysia (2 million ha), Borneo (2.4 million ha), and Sumatra (3.9 million ha). We demonstrate that 6% (or ≈880,000 ha) of tropical peatlands in the region had been converted to oil-palm plantations by the early 2000s. Conversion of peatswamp forests to oil palm led to biodiversity declines of 1% in Borneo (equivalent to four species of forest-dwelling birds), 3.4% in Sumatra (16 species), and 12.1% in Peninsular Malaysia (46 species). This land-use change also contributed to the loss of ≈140 million Mg of aboveground biomass carbon, and annual emissions of ≈4.6 million Mg of belowground carbon from peat oxidation. Additionally, the loss of peatswamp forests implies the loss of carbon sequestration service through peat accumulation, which amounts to ≈660,000 Mg of carbon annually. By 2010, 2.3 million ha of peatswamp forests were clear-felled, and currently occur as degraded lands. Reforestation of these clearings could enhance biodiversity by up to ≈20%, whereas oil-palm establishment would exacerbate species losses by up to ≈12%. To safeguard the region's biodiversity and carbon stocks, conservation and reforestation efforts should target Central Kalimantan, Riau, and West Kalimantan, which retain three-quarters (3.9 million ha) of the remaining peatswamp forests in Southeast Asia. PMID:21383161

  20. The potential for carbon storage in UK peatlands

    NASA Astrophysics Data System (ADS)

    Rowson, J.; Worrall, F.; Evans, M.; Bonn, A.; Reed, M.; Chapman, D.; Holden, J.

    2008-12-01

    Upland peat soils represent a large terrestrial carbon store and as such have the potential to be either an ongoing net sink of carbon or a significant net source of carbon. In the UK many upland peats are managed for a range of purposes but these purposes have rarely included carbon stewardship. However, there is now an opportunity to consider whether management practices could be altered to enhance storage of carbon in upland peats. Further, there are now voluntary and regulated carbon trading schemes operational throughout Europe that mean stored carbon, if verified, could have an economic and tradeable value. This means that new income streams could become available for upland management. The 'Sustainable Uplands' RELU project has developed a model for calculating carbon fluxes from peat soils that covers all carbon uptake and release pathways (e.g. fluvial and gaseous pathways). The model has been developed so that the impact of common management options within UK upland peats can be considered. The model was run for a decade from 1997-2006 and applied to an area of 550 km2 of upland peat soils in the Peak District. The study estimates that the region is presently a net sink of -62 Ktonnes CO2 equivalent at an average export of - 136 tonnes CO2 equivalent/km2/yr. If management interventions were targeted across the area the total sink could increase to -160 Ktonnes CO2/yr at an average export of- 219 tonnes CO2 equivalent/km2/yr. The model suggests which management interventions would be most effective and given present costs of peatland restoration and value of carbon offsets the study suggests that 51% of those areas, where a carbon benefit was estimated by modelling for targeted action of management interventions, would show a profit from carbon offsetting within 30 years.

  1. Remotely sensed evidence of tropical peatland conversion to oil palm

    PubMed Central

    Koh, Lian Pin; Miettinen, Jukka; Liew, Soo Chin; Ghazoul, Jaboury

    2011-01-01

    Rising global demands for food and biofuels are driving forest clearance in the tropics. Oil-palm expansion contributes to biodiversity declines and carbon emissions in Southeast Asia. However, the magnitudes of these impacts remain largely unquantified until now. We produce a 250-m spatial resolution map of closed canopy oil-palm plantations in the lowlands of Peninsular Malaysia (2 million ha), Borneo (2.4 million ha), and Sumatra (3.9 million ha). We demonstrate that 6% (or ≈880,000 ha) of tropical peatlands in the region had been converted to oil-palm plantations by the early 2000s. Conversion of peatswamp forests to oil palm led to biodiversity declines of 1% in Borneo (equivalent to four species of forest-dwelling birds), 3.4% in Sumatra (16 species), and 12.1% in Peninsular Malaysia (46 species). This land-use change also contributed to the loss of ≈140 million Mg of aboveground biomass carbon, and annual emissions of ≈4.6 million Mg of belowground carbon from peat oxidation. Additionally, the loss of peatswamp forests implies the loss of carbon sequestration service through peat accumulation, which amounts to ≈660,000 Mg of carbon annually. By 2010, 2.3 million ha of peatswamp forests were clear-felled, and currently occur as degraded lands. Reforestation of these clearings could enhance biodiversity by up to ≈20%, whereas oil-palm establishment would exacerbate species losses by up to ≈12%. To safeguard the region's biodiversity and carbon stocks, conservation and reforestation efforts should target Central Kalimantan, Riau, and West Kalimantan, which retain three-quarters (3.9 million ha) of the remaining peatswamp forests in Southeast Asia. PMID:21383161

  2. 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

  3. Malaspina Glacier, Alaska

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra satellite covers an area of 55 by 40 kilometers (34 by 25 miles) over the southwest part of the Malaspina Glacier and Icy Bay in Alaska. The composite of infrared and visible bands results in the snow and ice appearing light blue, dense vegetation is yellow-orange and green, and less vegetated, gravelly areas are in orange. According to Dr. Dennis Trabant (U.S. Geological Survey, Fairbanks, Alaska), the Malaspina Glacier is thinning. Its terminal moraine protects it from contact with the open ocean; without the moraine, or if sea level rises sufficiently to reconnect the glacier with the ocean, the glacier would start calving and retreat significantly. ASTER data are being used to help monitor the size and movement of some 15,000 tidal and piedmont glaciers in Alaska. Evidence derived from ASTER and many other satellite and ground-based measurements suggests that only a few dozen Alaskan glaciers are advancing. The overwhelming majority of them are retreating.

    This ASTER image was acquired on June 8, 2001. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next six years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along-term research and

  4. Occupational safety and health training in Alaska.

    PubMed

    Hild, C M

    1992-01-01

    We have eleven years of experience delivering a wide variety of worker education programs in cross-cultural settings to reduce the levels of occupational fatalities and injuries in Alaska. We published an instructional manual and informational poster for workers, on Alaska's "Right-To-Know" law regarding chemical and physical hazards. The "Job Hazard Recognition Program" curriculum for high school students has received national acclaim for being proactive in dealing with worker safety education before the student becomes a member of the work force. Adult educational programs and materials have been designed to include less lecture and formal presentation, and more practical "hands on" and on-the-job experience for specific trades and hazards. New industry specific manuals deal with hazardous waste reduction as a method to reduce harm to the employee. Difficulty in getting instructors and training equipment to rural locations is dealt with by becoming creative in scheduling classes, using locally available equipment, and finding regional contacts who support the overall program. Alternative approaches to funding sources include building on regional long-term plans and establishing complementary program objectives. PMID:1285824

  5. Estimating annual soil carbon loss in agricultural peatland soils using a nitrogen budget approach.

    PubMed

    Kirk, Emilie R; van Kessel, Chris; Horwath, William R; Linquist, Bruce A

    2015-01-01

    Around the world, peatland degradation and soil subsidence is occurring where these soils have been converted to agriculture. Since initial drainage in the mid-1800s, continuous farming of such soils in the California Sacramento-San Joaquin Delta (the Delta) has led to subsidence of up to 8 meters in places, primarily due to soil organic matter (SOM) oxidation and physical compaction. Rice (Oryza sativa) production has been proposed as an alternative cropping system to limit SOM oxidation. Preliminary research on these soils revealed high N uptake by rice in N fertilizer omission plots, which we hypothesized was the result of SOM oxidation releasing N. Testing this hypothesis, we developed a novel N budgeting approach to assess annual soil C and N loss based on plant N uptake and fallow season N mineralization. Through field experiments examining N dynamics during growing season and winter fallow periods, a complete annual N budget was developed. Soil C loss was calculated from SOM-N mineralization using the soil C:N ratio. Surface water and crop residue were negligible in the total N uptake budget (3 - 4 % combined). Shallow groundwater contributed 24 - 33 %, likely representing subsurface SOM-N mineralization. Assuming 6 and 25 kg N ha-1 from atmospheric deposition and biological N2 fixation, respectively, our results suggest 77 - 81 % of plant N uptake (129 - 149 kg N ha-1) was supplied by SOM mineralization. Considering a range of N uptake efficiency from 50 - 70 %, estimated net C loss ranged from 1149 - 2473 kg C ha-1. These findings suggest that rice systems, as currently managed, reduce the rate of C loss from organic delta soils relative to other agricultural practices. PMID:25822494

  6. Estimating Annual Soil Carbon Loss in Agricultural Peatland Soils Using a Nitrogen Budget Approach

    PubMed Central

    Kirk, Emilie R.; van Kessel, Chris; Horwath, William R.; Linquist, Bruce A.

    2015-01-01

    Around the world, peatland degradation and soil subsidence is occurring where these soils have been converted to agriculture. Since initial drainage in the mid-1800s, continuous farming of such soils in the California Sacramento-San Joaquin Delta (the Delta) has led to subsidence of up to 8 meters in places, primarily due to soil organic matter (SOM) oxidation and physical compaction. Rice (Oryza sativa) production has been proposed as an alternative cropping system to limit SOM oxidation. Preliminary research on these soils revealed high N uptake by rice in N fertilizer omission plots, which we hypothesized was the result of SOM oxidation releasing N. Testing this hypothesis, we developed a novel N budgeting approach to assess annual soil C and N loss based on plant N uptake and fallow season N mineralization. Through field experiments examining N dynamics during growing season and winter fallow periods, a complete annual N budget was developed. Soil C loss was calculated from SOM-N mineralization using the soil C:N ratio. Surface water and crop residue were negligible in the total N uptake budget (3 – 4 % combined). Shallow groundwater contributed 24 – 33 %, likely representing subsurface SOM-N mineralization. Assuming 6 and 25 kg N ha-1 from atmospheric deposition and biological N2 fixation, respectively, our results suggest 77 – 81 % of plant N uptake (129 – 149 kg N ha-1) was supplied by SOM mineralization. Considering a range of N uptake efficiency from 50 – 70 %, estimated net C loss ranged from 1149 – 2473 kg C ha-1. These findings suggest that rice systems, as currently managed, reduce the rate of C loss from organic delta soils relative to other agricultural practices. PMID:25822494

  7. Temperature, oxygen, and vegetation controls on decomposition in a James Bay peatland

    NASA Astrophysics Data System (ADS)

    Philben, Michael; Holmquist, James; MacDonald, Glen; Duan, Dandan; Kaiser, Karl; Benner, Ronald

    2015-06-01

    The biochemical composition of a peat core from James Bay Lowland, Canada, was used to assess the extent of peat decomposition and diagenetic alteration. Our goal was to identify environmental controls on peat decomposition, particularly its sensitivity to naturally occurring changes in temperature, oxygen exposure time, and vegetation. All three varied substantially during the last 7000 years, providing a natural experiment for evaluating their effects on decomposition. The bottom 50 cm of the core formed during the Holocene Climatic Optimum (~7000-4000 years B.P.), when mean annual air temperature was likely 1-2°C warmer than present. A reconstruction of the water table level using testate amoebae indicated oxygen exposure time was highest in the subsequent upper portion of the core between 150 and 225 cm depth (from ~2560 to 4210 years B.P.) and the plant community shifted from mostly Sphagnum to vascular plant dominance. Several independent biochemical indices indicated that decomposition was greatest in this interval. Hydrolysable amino acid yields, hydroxyproline yields, and acid:aldehyde ratios of syringyl lignin phenols were higher, while hydrolysable neutral sugar yields and carbon:nitrogen ratios were lower in this zone of both vascular plant vegetation and elevated oxygen exposure time. Thus, peat formed during the Holocene Climatic Optimum did not appear to be more extensively decomposed than peat formed during subsequent cooler periods. Comparison with a core from the West Siberian Lowland, Russia, indicates that oxygen exposure time and vegetation are both important controls on decomposition, while temperature appears to be of secondary importance. The low apparent sensitivity of decomposition to temperature is consistent with recent observations of a positive correlation between peat accumulation rates and mean annual temperature, suggesting that contemporary warming could enhance peatland carbon sequestration, although this could be offset by an

  8. Mechanisms for the suppression of methane production in peatland soils by a humic substance analog

    NASA Astrophysics Data System (ADS)

    Ye, R.; Keller, J. K.; Jin, Q.; Bohannan, B. J. M.; Bridgham, S. D.

    2014-01-01

    Methane (CH4) production is often impeded in many northern peatland soils, although inorganic terminal electron acceptors (TEAs) are usually present in low concentrations in these soils. Recent studies suggest that humic substances in wetland soils can be utilized as organic TEAs for anaerobic respiration and may directly inhibit CH4 production. Here we utilize the humic analog anthraquinone-2, 6-disulfonate (AQDS) to explore the importance of humic substances, and their effects on the temperature sensitivity of anaerobic decomposition, in two peatland soils. In a bog peat, AQDS was not instantly utilized as a TEA, but greatly inhibited the fermentative production of acetate, carbon dioxide (CO2), and hydrogen (H2), as well as CH4 production. When added together with glucose, AQDS was partially reduced after a lag period of 5 to 10 days. In contrast, no inhibitory effect of AQDS on fermentation was found in a fen peat and AQDS was readily reduced as an organic TEA. The addition of glucose and AQDS to both bog and fen peats caused complicated temporal dynamics in the temperature sensitivity of CH4 production, reflecting temporal changes in the temperature responses of other carbon processes with effects on methanogenesis. Our results show that the humic analog AQDS can act both as an inhibitory agent and a TEA in peatland soils. The high concentrations of humic substances in northern peatlands may greatly influence the effect of climate change on soil carbon cycling in these ecosystems.

  9. The hydrology of northern peatlands as affected by biogenic gas: Current developments and research needs

    USGS Publications Warehouse

    Rosenberry, D.O.; Glaser, P.H.; Siegel, D.I.

    2006-01-01

    Recent research indicates that accumulation and release of biogenic gas from northern peatlands may substantially affect future climate. Sudden release of free-phase gas bubbles into the atmosphere may preclude the conversion of methane to carbon dioxide in the uppermost oxic layer of the peat, resulting in greater contribution of methane to the atmosphere than is currently estimated. The hydrology of these peatlands also affects and is affected by this process, especially when gas is released suddenly and episodically. Indirect hydrological evidence indicates that ebullitive gas releases are relatively frequent in some peatlands and time-averaged rates may be significantly greater than diffusive releases. Estimates of free-phase gas contained in peat have ranged from 0 to nearly 20% of the peat volume. Abrupt changes in the volume of gas may alter hydraulic gradients and movement of water and solutes in peat, which in turn could alter composition and fluxes of the gas. Peat surfaces also move vertically and horizontally in response to accumulation and release of free-phase gas. Future research should address the distribution, temporal variability, and relative significance of ebullition in peatlands and the consequent hydrological responses to these gas-emission events. Copyright ?? 2006 John Wiley & Sons, Ltd.

  10. Large interannual variability in net ecosystem carbon dioxide exchange of a disturbed temperate peatland.

    PubMed

    Aslan-Sungur, Guler; Lee, Xuhui; Evrendilek, Fatih; Karakaya, Nusret

    2016-06-01

    Peatland ecosystems play an important role in the global carbon (C) cycle as significant C sinks. However, human-induced disturbances can turn these sinks into sources of atmospheric CO2. Long-term measurements are needed to understand seasonal and interannual variability of net ecosystem CO2 exchange (NEE) and effects of hydrological conditions and their disturbances on C fluxes. Continuous eddy-covariance measurements of NEE were conducted between August 2010 and April 2014 at Yenicaga temperate peatland (Turkey), which was drained for agricultural usage and for peat mining until 2009. Annual NEE during the three full years of measurement indicated that the peatland acted as a CO2 source with large interannual variability, at rates of 246, 244 and 663 g Cm(-2)yr(-1) for 2011, 2012, and 2013 respectively, except for June 2011, and May to July 2012. The emission strengths were comparable to those found for severely disturbed tropical peatlands. The peak CO2 emissions occurred in the dry summer of 2013 when water table level (WTL) was below a threshold value of -60 cm and soil water content (SCW) below a threshold value of 70% by volume. Water availability index was found to have a stronger explanatory power for variations in monthly ecosystem respiration (ER) than the traditional water status indicators (SCW and WTL). Air temperature, evapotranspiration and vapor pressure deficient were the most significant variables strongly correlated with NEE and its component fluxes of gross primary production and ER. PMID:26950633

  11. Carbon stocks of an old-growth forest and an anthropogenic peatland in southern Chile

    NASA Astrophysics Data System (ADS)

    Perez-Quezada, Jorge; Brito, Carla; Cabezas, Julian; Salvo, Patricia; Lemunao, Pedro; Flores, Ernesto; Valdés, Ariel; Fuentes, Juan Pablo; Galleguillos, Mauricio; Pérez, Cecilia

    2015-04-01

    The distribution of carbon in the different ecosystem stocks may change with direct human perturbation or climate change. We present a detailed description of the carbon stocks of an old-growth forest and an anthropogenic peatland (i.e., created by flooding, as a consequence of forest fires or logging). The study area was located in a private reserve in the Chiloé Island, southern Chile (41° 52' S, 73° 40' W). Sampling was done on plots separated 60 m from each other, in areas of approximately 30 ha for each ecosystem type. Total C was 1523 ± 117 Mg ha-1 in the forest and 130 ± 13.8 Mg ha-1 in the peatland, with 69.7% and 91.7% of this found belowground, respectively. In the forest, the necromass stock composed by logs and snags was high (183 Mg C ha-1), compared with the live-tree stock (264 Mg C ha-1) and with the C stored in the understory vegetation (14 Mg C ha-1). In the peatland, most of the C was stored in the most decomposed layer of peat, deeper in the ground. Because the anthropogenic peatland is experiencing a secondary succession, there is great potential to sequester back the C lost due to the perturbation. However, in most of the area where these ecosystems are found, the moss is being harvested for horticultural purposes.

  12. Peatland subsidence: are the biggest problems to be expected in the tropics?

    NASA Astrophysics Data System (ADS)

    Hooijer, A.; Erkens, G.; Vernimmen, R.; Page, S.; Triadi, B.; Applegate, G.

    2012-12-01

    Subsidence in drained peatlands is mainly caused by oxidation, which is highly temperature dependent. Subsidence rates, and the associated carbon emissions, are therefore far higher in tropical regions than in the temperate areas where most research has been done to date. In SE Asia alone, up to 25 Mha of lowland peatland is now being drained in ways that are unlikely to be sustainable beyond the short term, as surface lowering by about 4 metres within 50 years is expected to cause large-scale inundation and loss of agricultural production. Problems of similar scale may become apparent in other tropical regions, as agriculture expands into ever less suitable areas including peatlands. Applying recent findings on peat thickness, surface elevation and subsidence rate, we can now demonstrate the scale and timing of such problems for case study areas in Indonesia. To allow reduction of such impacts, which may be mitigated but often not prevented, it is important that local conditions are not seen in isolation, but rather investigated from a global perspective that integrates findings from different climate regions. Data from the Everglades and Sacramento Delta, peatlands in warm climates that were drained 100 years ago, provide the best analogue to what can be expected at a far larger scale in tropical regions.

  13. Tropical/Subtropical Peatland Development and Global CH4 during the Last Glaciation

    PubMed Central

    Xu, Hai; Lan, Jianghu; Sheng, Enguo; Liu, Yong; Liu, Bin; Yu, Keke; Ye, Yuanda; Cheng, Peng; Qiang, Xiaoke; Lu, Fengyan; Wang, Xulong

    2016-01-01

    Knowledge of peatland development over the tropical/subtropical zone during the last glaciation is critical for understanding the glacial global methane cycle. Here we present a well-dated ‘peat deposit-lake sediment’ alternate sequence at Tengchong, southwestern China, and discuss the peatland development and its linkage to the global glacial methane cycle. Peat layers were formed during the cold Marine Isotope Stage (MIS)-2 and -4, whereas lake sediments coincided with the relatively warm MIS-3, which is possibly related to the orbital/suborbital variations in both temperature and Asian summer monsoon intensity. The Tengchong peatland formation pattern is broadly synchronous with those over subtropical southern China and other tropical/subtropical areas, but it is clearly in contrast to those over the mid-high Northern Hemisphere. The results of this work suggest that the shifts of peatland development between the tropical/subtropical zone and mid-high Northern Hemisphere may have played important roles in the glacial/interglacial global atmospheric CH4 cycles. PMID:27465566

  14. Methane emissions from temperate herbaceous peatland in the Sanjiang Plain of Northeast China

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoyan; Song, Changchun; Guo, Yuedong; Sun, Xiaoxin; Zhang, Xinhou; Miao, Yuqing

    2014-08-01

    Peatlands are the significant source of atmospheric methane (CH4), which is produced during peat accumulation. In this study, we investigated CH4 emissions over two growing seasons from a Carex lasiocarpa-dominated peatland in the Sanjiang Plain in China using the static chamber technique. We also investigated the environmental factors controlling emissions during the two years of study, 2012 and 2013. CH4 emissions ranged from 0.07 to 56.01 mg CH4-C m-2 h-1 with mean values of 7.33 ± 1.65 mg C m-2 h-1, showing significant temporal patterns in both years with peak values in early June and middle August respectively. Variations in water table, soil temperature at 25 cm depth and soil's water-filled pore space together explained 66.7% of the observed temporal variation of CH4 fluxes by the step-wise regression. Rapid and short-lived precipitation events might have no immediate influence on CH4 emissions, which primarily depended on the actual soil aeration and moisture conditions. A simple relationship between single parameter and CH4 fluxes would be overruled once the water table dropped below the critical threshold for CH4 release. The amount of CH4 emitted from the herbaceous peatland in the Sanjiang Plain during the growing season was about 6.93 × 1012 mg C. Our results suggested that the herbaceous peatland in the Sanjiang Plain is an important source of atmospheric CH4.

  15. The role of fire in UK peatland and moorland management: the need for informed, unbiased debate

    PubMed Central

    Davies, G. Matt; Kettridge, Nicholas; Stoof, Cathelijne R.; Gray, Alan; Ascoli, Davide; Fernandes, Paulo M.; Marrs, Rob; Clay, Gareth D.; McMorrow, Julia; Vandvik, Vigdis

    2016-01-01

    Fire has been used for centuries to generate and manage some of the UK's cultural landscapes. Despite its complex role in the ecology of UK peatlands and moorlands, there has been a trend of simplifying the narrative around burning to present it as an only ecologically damaging practice. That fire modifies peatland characteristics at a range of scales is clearly understood. Whether these changes are perceived as positive or negative depends upon how trade-offs are made between ecosystem services and the spatial and temporal scales of concern. Here we explore the complex interactions and trade-offs in peatland fire management, evaluating the benefits and costs of managed fire as they are currently understood. We highlight the need for (i) distinguishing between the impacts of fires occurring with differing severity and frequency, and (ii) improved characterization of ecosystem health that incorporates the response and recovery of peatlands to fire. We also explore how recent research has been contextualized within both scientific publications and the wider media and how this can influence non-specialist perceptions. We emphasize the need for an informed, unbiased debate on fire as an ecological management tool that is separated from other aspects of moorland management and from political and economic opinions. This article is part of the themed issue ‘The interaction of fire and mankind’. PMID:27216512

  16. 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. PMID:26490883

  17. The role of fire in UK peatland and moorland management: the need for informed, unbiased debate.

    PubMed

    Davies, G Matt; Kettridge, Nicholas; Stoof, Cathelijne R; Gray, Alan; Ascoli, Davide; Fernandes, Paulo M; Marrs, Rob; Allen, Katherine A; Doerr, Stefan H; Clay, Gareth D; McMorrow, Julia; Vandvik, Vigdis

    2016-06-01

    Fire has been used for centuries to generate and manage some of the UK's cultural landscapes. Despite its complex role in the ecology of UK peatlands and moorlands, there has been a trend of simplifying the narrative around burning to present it as an only ecologically damaging practice. That fire modifies peatland characteristics at a range of scales is clearly understood. Whether these changes are perceived as positive or negative depends upon how trade-offs are made between ecosystem services and the spatial and temporal scales of concern. Here we explore the complex interactions and trade-offs in peatland fire management, evaluating the benefits and costs of managed fire as they are currently understood. We highlight the need for (i) distinguishing between the impacts of fires occurring with differing severity and frequency, and (ii) improved characterization of ecosystem health that incorporates the response and recovery of peatlands to fire. We also explore how recent research has been contextualized within both scientific publications and the wider media and how this can influence non-specialist perceptions. We emphasize the need for an informed, unbiased debate on fire as an ecological management tool that is separated from other aspects of moorland management and from political and economic opinions.This article is part of the themed issue 'The interaction of fire and mankind'. PMID:27216512

  18. Responsible management of peatlands in Canada, from peat industry to oil sands

    NASA Astrophysics Data System (ADS)

    Rochefort, Line

    2013-04-01

    Canada harbors one third of the peat resources of the world. Peat is an accumulated organic matter composed of dead and partly decomposed plant material, forming huge deposit through time in wetlands like peatlands and boreal coniferous swamps. Peat is a valuable resource as a growing media and soil amendments, an eco-friendly absorbent, also used as biofilters, for body care and for wastewater treatment. Peatlands also offer valuable ecological services : for example, they are the most efficient terrestrial ecosystem to store carbon on a long-term basis. Their ability to "cool off" the planet warrants a good look at their management. The horticultural peat industry of Canada has invested 22 years in R&D in habitat restoration and is now a strong leader in managing industrial peatlands in a sustainable way. The oil sand industry, which is strongly impacting the wetland landscapes of northern Canada, does realize that it has to reduce its ecological footprint, which is heavily criticized around the world. Decommissioned open mines near Fort McMurray have already begun recreating peatland ecosystems, and some restoration attempts of former oil pads are underway in the Peace River region. But the restoration of the largely disturbed wetland landscape of the oil sands is commanding innovative solutions.

  19. Application of infrared spectroscopy for assessing quality (chemical composition) of peatland plants, litter and soil

    NASA Astrophysics Data System (ADS)

    Straková, Petra; Laiho, Raija

    2016-04-01

    In this presentation, we assess the merits of using Fourier transform infrared (FTIR) spectra to estimate the organic matter composition in different plant biomass and peat soil samples. Infrared spectroscopy has a great potential in large-scale peatland studies that require low cost and high throughput techniques, as it gives a unique "chemical overview" of a sample, with all the chemical compounds present contributing to the spectrum produced. Our extensive sample sets include soil samples ranging from boreal to tropical peatlands, including sites under different environmental and/or land-use changes; above- and below-ground biomass of different peatland plant species; plant root mixtures. We mainly use FTIR to estimate (1) chemical composition of the samples (e.g., total C and N, C:N ratio, holocellulose, lignin and ash content), (2) proportion of each plant species in root mixtures, and (3) respiration of surface peat. The satisfactory results of our predictive models suggest that this experimental approach can, for example, be used as a screening tool in the evaluation of organic matter composition in peatlands during monitoring of their degradation and/or restoration success.

  20. Tropical/Subtropical Peatland Development and Global CH4 during the Last Glaciation

    NASA Astrophysics Data System (ADS)

    Xu, Hai; Lan, Jianghu; Sheng, Enguo; Liu, Yong; Liu, Bin; Yu, Keke; Ye, Yuanda; Cheng, Peng; Qiang, Xiaoke; Lu, Fengyan; Wang, Xulong

    2016-07-01

    Knowledge of peatland development over the tropical/subtropical zone during the last glaciation is critical for understanding the glacial global methane cycle. Here we present a well-dated ‘peat deposit-lake sediment’ alternate sequence at Tengchong, southwestern China, and discuss the peatland development and its linkage to the global glacial methane cycle. Peat layers were formed during the cold Marine Isotope Stage (MIS)-2 and -4, whereas lake sediments coincided with the relatively warm MIS-3, which is possibly related to the orbital/suborbital variations in both temperature and Asian summer monsoon intensity. The Tengchong peatland formation pattern is broadly synchronous with those over subtropical southern China and other tropical/subtropical areas, but it is clearly in contrast to those over the mid-high Northern Hemisphere. The results of this work suggest that the shifts of peatland development between the tropical/subtropical zone and mid-high Northern Hemisphere may have played important roles in the glacial/interglacial global atmospheric CH4 cycles.

  1. Tropical/Subtropical Peatland Development and Global CH4 during the Last Glaciation.

    PubMed

    Xu, Hai; Lan, Jianghu; Sheng, Enguo; Liu, Yong; Liu, Bin; Yu, Keke; Ye, Yuanda; Cheng, Peng; Qiang, Xiaoke; Lu, Fengyan; Wang, Xulong

    2016-01-01

    Knowledge of peatland development over the tropical/subtropical zone during the last glaciation is critical for understanding the glacial global methane cycle. Here we present a well-dated 'peat deposit-lake sediment' alternate sequence at Tengchong, southwestern China, and discuss the peatland development and its linkage to the global glacial methane cycle. Peat layers were formed during the cold Marine Isotope Stage (MIS)-2 and -4, whereas lake sediments coincided with the relatively warm MIS-3, which is possibly related to the orbital/suborbital variations in both temperature and Asian summer monsoon intensity. The Tengchong peatland formation pattern is broadly synchronous with those over subtropical southern China and other tropical/subtropical areas, but it is clearly in contrast to those over the mid-high Northern Hemisphere. The results of this work suggest that the shifts of peatland development between the tropical/subtropical zone and mid-high Northern Hemisphere may have played important roles in the glacial/interglacial global atmospheric CH4 cycles. PMID:27465566

  2. Trends in Alaska's People and Economy.

    ERIC Educational Resources Information Center

    Leask, Linda; Killorin, Mary; Martin, Stephanie

    This booklet provides data on Alaska's population, economy, health, education, government, and natural resources, including specific information on Alaska Natives. Since 1960, Alaska's population has tripled and become more diverse, more stable, older, less likely to be male or married, and more concentrated. About 69 percent of the population…

  3. 50 CFR 32.21 - Alaska.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... WILDLIFE REFUGE SYSTEM HUNTING AND FISHING Refuge-Specific Regulations for Hunting and Fishing § 32.21 Alaska. Alaska refuges are opened to hunting, fishing and trapping pursuant to the Alaska National Interest Lands Conservation Act (Pub. L. 96-487, 94 Stat. 2371). Information regarding specific...

  4. 50 CFR 32.21 - Alaska.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 9 2014-10-01 2014-10-01 false Alaska. 32.21 Section 32.21 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED) THE NATIONAL WILDLIFE REFUGE SYSTEM HUNTING AND FISHING Refuge-Specific Regulations for Hunting and Fishing § 32.21 Alaska. Alaska refuges are opened to...

  5. Some Books about Alaska Received in 1986.

    ERIC Educational Resources Information Center

    Alaska State Dept. of Education, Juneau. Div. of State Libraries.

    This publication is an annotated listing of 143 books about Alaska or the Arctic, received by the Alaska Division of State Libraries in 1986. Most of the material is current or published in recent years, with the exception of government publications. Categories are juvenile, adult non-fiction, adult fiction, and reference. A few Alaska state and…

  6. 33 CFR 80.1705 - Alaska.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Alaska. 80.1705 Section 80.1705 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Alaska § 80.1705 Alaska. The 72 COLREGS shall apply on all the sounds,...

  7. The long-term fate of permafrost peatlands under rapid climate warming

    NASA Astrophysics Data System (ADS)

    Swindles, Graeme T.; Morris, Paul J.

    2016-04-01

    High-latitude permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, there is much concern that climate warming and subsequent permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Unfortunately, field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to rapid warming in the twentieth century. Here we use a high-resolution palaeoecological approach to understand the longer-term response of peatlands in Subarctic Sweden in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed in response to climatic warming, culminating in collapse of the peat domes. Commonalities between study sites lead us to propose a five-phase model for permafrost peatland response to climatic warming. This model suggests a shared ecohydrological trajectory towards a common end point: inundated Arctic fen. Although carbon accumulation is rapid in such sites, and thus peatland ecosystem services are resumed, saturated soil conditions are likely to cause elevated methane emissions that have implications for climate-feedback mechanisms. We outline our plans to test the model published in Swindles et al. (2015) using the same methodological approach in other high-latitude locations, including zones of continuous and discontinuous permafrost. Reference: Swindles, G.T., Morris, P.J., Mullan, D., Watson, E.J., Turner, T.E., Roland, T., Amesbury, M.J., Kokfelt, U., Schoning, K., Pratte, S., Gallego-Sala, A., Charman, D.J., Sanderson, N., Garneau, M., Carrivick, J.L., Woulds, C

  8. Estimating evapotranspiration in different rain-fed peatlands from groundwater level changes

    NASA Astrophysics Data System (ADS)

    Dettmann, Ullrich; Maurer, Eike; Bechtold, Michel; Brümmer, Christian; Tiemeyer, Bärbel

    2014-05-01

    Biogeochemical processes in peatlands are strongly controlled by the hydrological conditions of these environments. One of the key parameters controlling the water balance is the evapotranspiration, which can be calculated e.g. by the FAO crop reference evapotranspiration or the Penman-Monteith equation as a function of atmospheric conditions and plant specific parameters. These parameters are well investigated for agricultural crops and forests but poorly for most peatland vegetation types. Direct measurement of the evapotranspiration is possible with weighing lysimeters or the eddy-covariance technique, but expensive and time consuming. In many peatlands and riparian areas groundwater table changes are characterized by diurnal fluctuations (daytime decline, night-time recovery) caused by the evapotranspiration and groundwater recharge. White introduced 1932 a method to calculate the evapotranspiration from these diurnal fluctuations. In contrast to traditional evapotranspiration models only a small number of variables need to be measured (groundwater level changes, possibly precipitation) or calculated (specific yield). Over the last decades, several studies and modifications of the White method have been published. Several authors showed the applicability of the method for riparian areas and fens, but this relies on the assumption of a constant recharge over the whole day. As there is no groundwater inflow at rain-fed peatlands, recovery during night-time can only result from redistribution in the soil profile or from lateral flow processes within the peatland. Thus, approaches to calculate evapotranspiration from diurnal groundwater fluctuations used to date need to be adapted. Based on 50 hydrographs measured in 6 rain-fed peatlands in Germany characterized by different soil properties, land use and vegetation, we systematically analyzed diurnal patterns of the groundwater levels. These patterns were spatially and temporally very variable. At some sites, the

  9. Multi-decadal water-table manipulation alters peatland hydraulic structure and moisture retention.

    NASA Astrophysics Data System (ADS)

    Moore, Paul; Morris, Paul; Waddington, James

    2015-04-01

    Peatlands are a globally important store of freshwater and soil carbon. However, there is a concern that these water and carbon stores may be at risk due to climate change as vapour pressure deficits, evapotranspiration and summer moisture deficits are expected to increase, leading to greater water table (WT) drawdown in northern continental regions where peatlands are prevalent. We argue that in order to evaluate the hydrological response (i.e. changes in WT level, storage, surface moisture availability, and moss evaporation) of peatlands under future climate change scenarios, the hydrophysical properties of peat and disparities between microforms must be well understood. A peatland complex disturbed by berm construction in the 1950's was used to examine the long-term impact of WT manipulation on peatland hydraulic properties and moisture retention at three adjacent sites with increasing average depth to WT (WET, INTermediate reference, and DRY). All three sites exhibited a strong depth dependence for hydraulic conductivity, specific yield, and bulk density. Moreover, the effect of microform on near-surface peat properties tended to be greater than the site effect. Bulk density was found to explain a high amount of variance (r2 > 0.69) in moisture retention across a range of pore water pressures (-15 to -500 cm H2O), where bulk density tended to be higher in hollows. The estimated residual water content for surface Sphagnum samples, while on average lower in hummocks (0.082 m3 m-3) versus hollows (0.087 m3 m-3), increased from WET (0.058 m3 m-3) to INT (0.088 m3 m-3) to DRY (0.108 m3 m-3) which has important implications for moisture stress under conditions of persistent WT drawdown. While we did not observe significant differences between sites, we did observe a greater proportional coverage and greater relative height of hummocks at the drier sites. Given the potential importance of microtopographic succession for altering peatland hydraulic structure, our

  10. Modeling Complex Water Table Effects on Net CO2 Exchange of Western Canadian Peatlands

    NASA Astrophysics Data System (ADS)

    Mezbahuddin, Mohammad; Grant, Robert; Flanagan, Lawrence

    2013-04-01

    Water table fluctuation is one of the key controls governing peatland carbon balance under current and future climatic conditions. Seasonal and inter-annual variations in water table depths can alter the balance between peatland primary production and respiration and so cause a peatland to change between a sink and a source of carbon. Water table fluctuations can affect primary production and respiration through its influence on evapotranspiration, plant water and nutrient uptake and on microbial decomposition. Simulating water table effects on current and future net ecosystem productivity (NEP) of peatlands thus demands models with coupled soil-plant-atmosphere schemes for gases, water, energy, carbon and nutrients (N, P). We combined a 3-dimensional water transport scheme and prognostic water table dynamics with an existing ecosystem model ecosys in order to examine the water table effects on seasonal and inter-annual variability in NEP of a moderately rich fen peatland in Alberta, Canada. Simulated hourly ecosystem energy and CO2 fluxes along with hourly water table depths correlated very well (R2 ~ 0.75) with measurements at the site from 2003 to 2009, during which the water table declined gradually. We compared modeled and measured fluxes at hourly and seasonal time scales in years with contrasting water table depths in order to see how water table fluctuations altered the diurnal and seasonal patterns of NEP. In the model, shallow water tables limited root and soil aeration, slowing root and microbial growth, and hence nutrient uptake. This reduced gross primary productivity (GPP) but also ecosystem respiration (RE), so that the peatland remained a substantial net carbon sink. In the model, deeper water tables caused more rapid microbial and root growth, and hence more rapid mineralization and nutrient uptake, and hence greater GPP. Deeper water tables also caused near-surface drying which slightly reduced near surface peat decomposition. However this

  11. Environmental indifference? A critique of environmentally deterministic theories of peatland archaeological site construction in Ireland

    NASA Astrophysics Data System (ADS)

    Plunkett, G.; McDermott, C.; Swindles, G. T.; Brown, D. M.

    2013-02-01

    Climate change, whether gradual or sudden, has frequently been invoked as a causal factor to explain many aspects of cultural change during the prehistoric and early historic periods. Critiquing such theories has often proven difficult, not least because of the imprecise dating of many aspects of the palaeoclimate or archaeological records and the difficulties of merging the two strands of research. Here we consider one example of the archaeological record - peatland site construction in Ireland - which has previously been interpreted in terms of social response to climate change and examine whether close scrutiny of the archaeological and palaeoenvironmental records upholds the climatically deterministic hypotheses. We evaluate evidence for phasing in the temporal distribution of trackways and related sites in Irish peatlands, of which more than 3500 examples have been recorded, through the examination of ˜350 dendrochronological and 14C dates from these structures. The role of climate change in influencing when such sites were constructed is assessed by comparing visually and statistically the frequency of sites over the last 4500 years with well-dated, multiproxy climate reconstructions from Irish peatlands. We demonstrate that national patterns of “peatland activity” exist that indicate that the construction of sites in bogs was neither a constant nor random phenomenon. Phases of activity (i.e. periods in which the number of structures increased), as well as the ‘lulls’ that separate them, show no consistent correlation with periods of wetter or drier conditions on the bogs, suggesting that the impetus for the start or cessation of such activity was not climatically-determined. We propose that trigger(s) for peatland site construction in Ireland must instead also be sought within the wider, contemporary social background. Perhaps not surprisingly, a comparison with archaeological and palynological evidence shows that peatland activity tends to occur at

  12. Uptake of ¹³⁷Cs by berries, mushrooms and needles of Scots pine in peatland forests after wood ash application.

    PubMed

    Vetikko, Virve; Rantavaara, Aino; Moilanen, Mikko

    2010-12-01

    Increasing use of wood fuels for energy production in Finland since the 1990s