Saprophytic and Potentially Pathogenic Fusarium Species from Peat Soil in Perak and Pahang

PubMed Central

Karim, Nurul Farah Abdul; Mohd, Masratulhawa; Nor, Nik Mohd Izham Mohd; Zakaria, Latiffah

2016-01-01

Isolates of Fusarium were discovered in peat soil samples collected from peat swamp forest, waterlogged peat soil, and peat soil from oil palm plantations. Morphological characteristics were used to tentatively identify the isolates, and species confirmation was based on the sequence of translation elongation factor-1α (TEF-1α) and phylogenetic analysis. Based on the closest match of Basic Local Alignment Search Tool (BLAST) searches against the GenBank and Fusarium-ID databases, five Fusarium species were identified, namely F. oxysporum (60%), F. solani (23%), F. proliferatum (14%), F. semitectum (1%), and F. verticillioides (1%). From a neighbour-joining tree of combined TEF-1α and β-tubulin sequences, isolates from the same species were clustered in the same clade, though intraspecies variations were observed from the phylogenetic analysis. The Fusarium species isolated in the present study are soil inhabitants and are widely distributed worldwide. These species can act as saprophytes and decomposers as well as plant pathogens. The presence of Fusarium species in peat soils suggested that peat soils could be a reservoir of plant pathogens, as well-known plant pathogenic species such F. oxysporum, F. solani, F. proliferatum, and F. verticillioides were identified. The results of the present study provide knowledge on the survival and distribution of Fusarium species. PMID:27019679

Effect of peat on the accumulation and translocation of heavy metals by maize grown in contaminated soils.

PubMed

Stanislawska-Glubiak, Ewa; Korzeniowska, Jolanta; Kocon, Anna

2015-03-01

Incorporation of organic materials into soil improves the soil sorption capacity, while limiting the mobility of metals in soil and their availability to plants. These effects can be taken advantage for remediation of soils polluted with heavy metals. The objective of this study is to assess the remediatory potential of peat applied to soils with concomitant pollution with Cd, Pb, and Zn. Two 1-year experiments were run in microplots in which maize was grown as the test plant. The following treatments were compared on two soils (sandy soil and loess): (1) control, (2) heavy metals (HM), (3) HM + peat in a single dose, and (4) HM + peat in a double dose. Maize was harvested in the maturity stage; the biomass of roots and aerial parts, including grain and cobs, was measured. Besides, concentration of metals in all those plant parts and the net photosynthetic rate and transpiration rate were determined. The approach of using peat in soil remediation led to satisfactory results on sandy soil only. The application of peat to sandy soil caused significant changes in the accumulation of the metals and their translocation from roots to other parts of plants, which resulted in a higher intensity of photosynthesis and an increase in the maize biomass compared to the HM treatment.

Evaluating the hydraulic and transport properties of peat soil using pore network modeling and X-ray micro computed tomography

NASA Astrophysics Data System (ADS)

Gharedaghloo, Behrad; Price, Jonathan S.; Rezanezhad, Fereidoun; Quinton, William L.

2018-06-01

Micro-scale properties of peat pore space and their influence on hydraulic and transport properties of peat soils have been given little attention so far. Characterizing the variation of these properties in a peat profile can increase our knowledge on the processes controlling contaminant transport through peatlands. As opposed to the common macro-scale (or bulk) representation of groundwater flow and transport processes, a pore network model (PNM) simulates flow and transport processes within individual pores. Here, a pore network modeling code capable of simulating advective and diffusive transport processes through a 3D unstructured pore network was developed; its predictive performance was evaluated by comparing its results to empirical values and to the results of computational fluid dynamics (CFD) simulations. This is the first time that peat pore networks have been extracted from X-ray micro-computed tomography (μCT) images of peat deposits and peat pore characteristics evaluated in a 3D approach. Water flow and solute transport were modeled in the unstructured pore networks mapped directly from μCT images. The modeling results were processed to determine the bulk properties of peat deposits. Results portray the commonly observed decrease in hydraulic conductivity with depth, which was attributed to the reduction of pore radius and increase in pore tortuosity. The increase in pore tortuosity with depth was associated with more decomposed peat soil and decreasing pore coordination number with depth, which extended the flow path of fluid particles. Results also revealed that hydraulic conductivity is isotropic locally, but becomes anisotropic after upscaling to core-scale; this suggests the anisotropy of peat hydraulic conductivity observed in core-scale and field-scale is due to the strong heterogeneity in the vertical dimension that is imposed by the layered structure of peat soils. Transport simulations revealed that for a given solute, the effective diffusion coefficient decreases with depth due to the corresponding increase of diffusional tortuosity. Longitudinal dispersivity of peat also was computed by analyzing advective-dominant transport simulations that showed peat dispersivity is similar to the empirical values reported in the same peat soil; it is not sensitive to soil depth and does not vary much along the soil profile.

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

NASA Astrophysics Data System (ADS)

Stolarczyk, Mateusz

2016-04-01

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

Soil microbial respiration from various microhabitats in Arctic landscape: impact of soil type, environmental conditions and soil age

NASA Astrophysics Data System (ADS)

Biasi, Christina; Jokinen, Simo; Marushchak, Maija; Trubnikova, Tatiana; Hämäläinen, Kai; Oinonen, Markku; Martikainen, Pertti

2014-05-01

Soil respiration is the second largest C flux between atmosphere and terrestrial ecosystems after gross primary production. Carbon dioxide released from soils is thus a major contributor to the atmospheric CO2 concentration. Despite the global importance, soil respiration and its components (heterotrophic and autotrophic respiration) remain poorly understood and not well constrained fluxes of the terrestrial C cycle. This is particularly true for the Arctic, where huge amounts of the Earth's soil carbon is stored. Here, we report on heterotrophic soil respiration rates from various Arctic tundra microhabitats measured in situ. The study site was Seida (67°07'N, 62°57'E, 100 m a.s.l.) which is characterized by typical sub-arctic permafrost landscape which comprises raised, vegetated permafrost peat plateaus, interspersed with spots of bare peat surfaces (peat circles), and upland mineral soils. We used isotope partitioning approach based on differences in natural abundance of 14C between soil and plants to separate sources of soil-respired CO2. In addition, the tradition trenching approach was employed. Complementary laboratory incubations with homogenized soil were conducted to assess primary decomposability of the soils and to identify age of the CO2 released and thus get more information on the nature of the sources of respiration. The major aim was to link SMR rates with of soil type, land cover class, soil physic-chemical properties (e.g. water content), soil C stocks and age of soil. Results show that, despite profound differences in soil characteristics and primary decomposability of organic matter, surface CO2 fluxes derived from soil microbial respiration rates were rather similar between microhabitats. The only factor which influenced, at least to some extent, the respiration rates was total soil C (and N) stocks in surface soils. There was some evidence for reduced soil-related CO2 emissions from peatlands, though results were not consistent between the methods applied. It seems that the lower decomposability of peat is largely outweighed by higher C stocks at field conditions. Surprisingly, the bare surfaces (peat circles) with 3500 years old C at the surface exhibited about the largest soil microbial respiration rates among all sites as shown by both methods. This is likely due to the immature status of the peat which was during the bulk of its developmental time protected by permafrost, together with high C-densities. The observation is particularly relevant for decomposition of deeper peat at the permafrost-active layer interface in the large vegetated peat plateaus, where soil material similar to the bare surfaces can be found. The results suggest that the chemical nature and high age of the soil SOC in deep peat does not solely guarantee for resistance to decay. Thus, the study highlights risks for potential re-mobilization of C in deep peat soils following thawing. Soil microbial respiration rates need to be better known when predicting the overall carbon sink/source character of tundra ecosystems in a warming climate. Biasi C., Jokinen S., Marushchak M., Hämäläinen K., Trubnikova T., Oinonen M., Martikainen P. (2013). Microbial respiration in Arctic upland and peat soils as source of CO2. Ecosystems. DOI: 10.1007/s10021-013-9710-z.

A Study on Factors Affecting Strength of Solidified Peat through XRD and FESEM Analysis

NASA Astrophysics Data System (ADS)

Rahman, J. A.; Napia, A. M. A.; Nazri, M. A. A.; Mohamed, R. M. S. R.; Al-Geethi, A. S.

2018-04-01

Peat is soft soil that often causes multiple problems to construction. Peat has low shear strength and high deformation characteristics. Thus, peat soil needs to be stabilized or treated. Study on peat stabilization has been conducted for decades with various admixtures and mixing formulations. This project intends to provide an overview of the solidification of peat soil and the factors that affecting the strength of solidified peat soil. Three types of peats which are fabric, hemic and sapric were used in this study to understand the differences on the effect. The understanding of the factors affecting strength of solidified peat in this study is limited to XRD and FESEM analysis only. Peat samples were collected at Pontian, Johor and Parit Raja, Johor. Peat soil was solidified using fly ash, bottom ash and Portland cement with two mixing formulation following literature review. The solidified peat were cured for 7 days, 14 days, 28 days and 56 days. All samples were tested using Unconfined Compressive Strength Test (UCS), X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM). The compressive strength test of solidified peat had shown consistently increase of sheer strength, qu for Mixing 1 while decrease of its compressive strength value for Mixing 2. All samples were tested and compared for each curing days. Through XRD, it is found that all solidified peat are dominated with pargasite and richterite. The highest qu is Fabric Mixing 1(FM1) with the value of 105.94 kPa. This sample were proven contain pargasite. Samples with high qu were observed to be having fly ash and bottom ash bound together with the help of pargasite. Sample with decreasing strength showed less amount of pargasite in it. In can be concluded that XRD and FESEM findings are in line with UCS values.

Impact of drainage on wettability of fen peat-moorsh soils

NASA Astrophysics Data System (ADS)

Szajdak, L.; Szatyłowicz, J.; Brandyk, T.

2009-04-01

High water retention in peat is attributed to structural voids (macro-pores) due to the partial degradation of the structure of peat-forming plants, and molecular absorption sites (micro-pores) associated with the formation of humic substances. Water retention by the heterogeneously-structured system in peat organic matter depends on the chemical structure of solid surfaces. These naturally wet solids, if dried sufficiently, lose the ability to rewet quickly when immersed in water. The ability of peat surfaces to attract and hold water is attributed to hydrophilic functional groups which characterize the organic substances of peat. The investigations of chemical and physical properties were performed for three different peat-moorsh soils located in the Biebrza River Valley in Poland. All examined soils were used as meadow. Soil samples were taken from two depths: 5-10 cm (moorsh) and 50-80 cm (peat). Total organic carbon (TOC), dissolved organic carbon (DOC) and humic acids (HA) extracted from these samples were analysed. Also basic physical properties such as ash content and bulk density were measured. Wetting behavior of soils was quantified using water drop penetration time test (WDPT) and measured values of the soil-water contact angle using sessile drop method. The measurements were conducted on air-dry soil samples which volumetric moisture content was not exceeding 7%. The significant differences in the concentrations of TOC, DOC and properties of HA between two investigated depth of among peat and moorsh samples were observed. The measured concentrations of total organic carbon in the considered soils ranged from 37.2 to 45.6%. Generally, the decrease of total organic carbon concentration with depth of profiles was observed. The contents of dissolved organic carbon in the soils ranged from 5.3 to 19.4%. The quantities of dissolved organic carbon decreased simultaneously with E4/E6 values and with the depth of the soil profiles. For the investigated peat's, an increase of the depth is accompanied by the decrease in the degree of humification or an increase in chemical maturity of HA. The measured values of the contact angle for investigated soils were in the range from 81.4˚ to 114.3˚ what indicates their high water repellency. The WDPT was positively correlated with total organic carbon, organic matter and humic acids content while ash content, soil bulk density, pH and absorbance were correlated negatively. The highest value of correlation coefficient (statistically significant) was obtained for relation between WDPT and ash content. The soil water contact angle was less correlated with peat-moorsh soil properties in comparison with WDPT with one exception pH. The pH against the contact angle indicates tendency of increasing the contact angle with decreasing pH.

Structure of peat soils and implications for biogeochemical processes and hydrological flow

NASA Astrophysics Data System (ADS)

Rezanezhad, F.; McCarter, C. P. R.; Gharedaghloo, B.; Kleimeier, C.; Milojevic, T.; Liu, H.; Weber, T. K. D.; Price, J. S.; Quinton, W. L.; Lenartz, B.; Van Cappellen, P.

2017-12-01

Permafrost peatlands contain globally important amounts of soil organic carbon and play major roles in global water, nutrient and biogeochemical cycles. The structure of peatland soils (i.e., peat) are highly complex with unique physical and hydraulic properties; where significant, and only partially reversible, shrinkage occurs during dewatering (including water table fluctuations), compression and/or decomposition. These distinct physical and hydraulic properties controls water flow, which in turn affect reactive and non-reactive solute transport (such as, sorption or degradation) and biogeochemical functions. Additionally, peat further attenuates solute migration through molecular diffusion into the inactive pores of Sphagnum dominated peat. These slow, diffusion-limited solute exchanges between the pore regions may give rise to pore-scale chemical gradients and heterogeneous distributions of microbial habitats and activity in peat soils. Permafrost peat plateaus have the same essential subsurface characteristics as other widely organic soil-covered peatlands, where the hydraulic conductivity is related to the degree of decomposition and soil compression. Increasing levels of decomposition correspond with a reduction of effective pore diameter and consequently restrict water and solute flow (by several orders of magnitude in hydraulic conductivity between the ground surface and a depth of 50 cm). In this presentation, we present the current knowledge of key physical and hydraulic properties related to the structure of globally available peat soils and discuss their implications for water storage, flow and the migration of solutes.

Estimating methane gas production in peat soils of the Florida Everglades using hydrogeophysical methods

NASA Astrophysics Data System (ADS)

Wright, William; Comas, Xavier

2016-04-01

The spatial and temporal variability in production and release of greenhouse gases (such as methane) in peat soils remains uncertain, particularly for low-latitude peatlands like the Everglades. Ground penetrating radar (GPR) is a hydrogeophysical tool that has been successfully used in the last decade to noninvasively investigate carbon dynamics in peat soils; however, application in subtropical systems is almost non-existent. This study is based on four field sites in the Florida Everglades, where changes in gas content within the soil are monitored using time-lapse GPR measurements and gas releases are monitored using gas traps. A weekly methane gas production rate is estimated using a mass balance approach, considering gas content estimated from GPR, gas release from gas traps and incorporating rates of diffusion, and methanotrophic consumption from previous studies. Resulting production rates range between 0.02 and 0.47 g CH4 m-2 d-1, falling within the range reported in literature. This study shows the potential of combining GPR with gas traps to monitor gas dynamics in peat soils of the Everglades and estimate methane gas production. We also show the enhanced ability of certain peat soils to store gas when compared to others, suggesting that physical properties control biogenic gas storage in the Everglades peat soils. Better understanding biogenic methane gas dynamics in peat soils has implications regarding the role of wetlands in the global carbon cycle, particularly under a climate change scenario.

Distributions of Heavy Metals and Benzo[ a]pyrene in Oligotrophic Peat Soils and Peat Gleyzems of Northeastern Sakhalin

NASA Astrophysics Data System (ADS)

Lipatov, D. N.; Shcheglov, A. I.; Manakhov, D. V.; Karpukhin, M. M.; Zavgorodnyaya, Yu. A.; Tsvetnova, O. B.

2018-05-01

The contents and profile distributions of Cr, Ni, Cu, Zn, Cd, Hg, Pb, and benzo[a]pyrene in oligotrophic peat soils, oligotrophic peat gley soils (Dystric Fibric Histosols), humus-impregnated peat gleyzems (Dystric Histic Gleysols), and mucky gleyzems (Dystric Gleysols) have been analyzed with consideration for their degree of oligotrophicity and anthropogenic loads. Horizons with the accumulation (O, Tpyr, TT) and removal (Ghi,e) of heavy metals have been revealed. The increase in the content of heavy metals and benzo[ a]pyrene in the upper layer of oligotrophic peat soils under technogenic fallouts in the impact zone of flare and motor transport has been considered. Statistical parameters of the spatial variation of parameters in organic and gley horizons have been calculated. The variation coefficients of pollutant elements (Pb and Zn) in the surface horizons of soils increase to 100-125%. Positive correlations revealed between the content of some heavy metals in litter indicate their bioaccumulation and possible joint input with aerotechnogenic fallouts. No correlations are found between the contents of benzo[ a]pyrene and heavy metals, but a reliable negative correlation with the ash content is noted in the peat horizon.

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

NASA Astrophysics Data System (ADS)

Wright, William J.

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

Uncertainty in peat volume and soil carbon estimated using ground-penetrating radar and probing

Treesearch

Andrew D. Parsekian; Lee Slater; Dimitrios Ntarlagiannis; James Nolan; Stephen D. Sebestyen; Randall K. Kolka; Paul J. Hanson

2012-01-01

Estimating soil C stock in a peatland is highly dependent on accurate measurement of the peat volume. In this study, we evaluated the uncertainty in calculations of peat volume using high-resolution data to resolve the three-dimensional structure of a peat basin based on both direct (push probes) and indirect geophysical (ground-penetrating radar) measurements. We...

Biogenic Gas Dynamics in Peat Soil Blocks using Ground Penetrating Radar: a Comparative Study in the Laboratory between Peat Soils from the Everglades and from two Northern Peatlands in Minnesota and Maine

NASA Astrophysics Data System (ADS)

Cabolova, Anastasija

Peatlands cover a total area of approximately 3 million square kilometers and are one of the largest natural sources of atmospheric methane ( CH4) and carbon dioxide (CO 2). Most traditional methods used to estimate biogenic gas dynamics are invasive and provide little or no information about lateral distribution of gas. In contrast, Ground Penetrating Radar (GPR) is an emerging technique for non-invasive investigation of gas dynamics in peat soils. This thesis establishes a direct comparison between gas dynamics (i.e. build-up and release) of four different types of peat soil using GPR. Peat soil blocks were collected at peatlands with contrasting latitudes, including the Everglades, Maine and Minnesota. A unique two-antenna GPR setup was used to monitor biogenic gas buildup and ebullition events over a period of 4.5 months, constraining GPR data with surface deformation measurements and direct CH 4 and CO2 concentration measurements. The effect of atmospheric pressure was also investigated. This study has implications for better understanding global gas dynamics and carbon cycling in peat soils and its role in climate change.

Resilient modulus characteristics of soil subgrade with geopolymer additive in peat

NASA Astrophysics Data System (ADS)

Zain, Nasuhi; Hadiwardoyo, Sigit Pranowo; Rahayu, Wiwik

2017-06-01

Resilient modulus characteristics of peat soil are generally very low with high potential of deformation and low bearing capacity. The efforts to improve the peat subgrade resilient modulus characteristics is required, one among them is by adding the geopolymer additive. Geopolymer was made as an alternative to replace portland cement binder in the concrete mix in order to promote environmentally friendly, low shrinkage value, low creep value, and fire resistant material. The use of geopolymer to improve the mechanical properties of peat as a road construction subgrade, hence it becomes important to identify the effect of geopolymer addition on the resilient modulus characteristics of peat soil. This study investigated the addition of 0% - 20% geopolymer content on peat soil derived from Ogan Komering Ilir, South Sumatera Province. Resilient modulus measurement was performed by using cyclic triaxial test to determine the resilience modulus model as a function of deviator stresses and radial stresses. The test results showed that an increase in radial stresses did not necessarily lead to an increase in modulus resilient, and on the contrary, an increase in deviator stresses led to a decrease in modulus resilient. The addition of geopolymer in peat soil provided an insignificant effect on the increase of resilient modulus value.

Effect of freeze-thaw cycles on greenhouse gas fluxes from peat soils

NASA Astrophysics Data System (ADS)

Oh, H. D.; Rezanezhad, F.; Markelov, I.; McCarter, C. P. R.; Van Cappellen, P.

2017-12-01

The ongoing displacement of climate zones by global warming is increasing the frequency and intensity of freeze-thaw cycles in middle and high latitude regions, many of which are dominated by organic soils such as peat. Repeated freezing and thawing of soils changes their physical properties, geochemistry, and microbial community structure, which together govern the biogeochemical cycling of carbon and nutrients. In this presentation, we focus on how freeze-thaw cycles influence greenhouse gas fluxes from peat using a newly developed experimental soil column system that simulates realistic soil temperature profiles during freeze-thaw cycles. We measured the surface and subsurface changes to gas and aqueous phase chemistry to delineate the diffusion pathways and quantify soil greenhouse gas fluxes during freeze-thaw cycles using sulfur hexafluoride (SF6) as a conservative tracer. Three peat columns were assembled inside a temperature controlled chamber with different soil structures. All three columns were packed with 40 cm of undisturbed, slightly decomposed peat, where the soil of two columns had an additional 10 cm layer on top (one with loose Sphagnum moss and one with an impermeable plug). The results indicate that the release of SF6 and CO2 gas from the soil surface was influenced by the recurrent development of a physical ice barrier, which prevented gas exchange between the soil and atmosphere during freezing conditions. With the onset of thawing a pulse of SF6 and CO2 occurred, resulting in a flux of 3.24 and 2095.52 µmol/m2h, respectively, due to the build-up of gases in the liquid-phase pore space during freezing. Additionally, we developed a model to determine the specific diffusion coefficients for each peat column. These data allow us to better predict how increased frequency and intensity of freeze-thaw cycles will affect greenhouse gas emissions in northern peat soils.

Deccesion of peat-moorsh soils under different land use

NASA Astrophysics Data System (ADS)

Lipka, K.; Zając, E.

2009-04-01

Use of peatlands has a serious impact on soil properties as well as on loss of organic matter. On the basis of survey carried out in 1976, 1993 and 2001 in the Mrowla river valley near Rzeszow, authors analysed changes of the peat-moorsh soils under different land use. The 25- year period was analysed. Survey results comprised: loss of organic matter, advance of moorsh forming process and change of prognostic soil-moisture complexes (after Okruszko). Stratigraphic profiles made in the years1996-2001 were compared and rate of organic mass loss was calculated. The highest values were stated for ploughfields with crop rotation (root plants, industrial plants and cereals). Intensified soil aeration and moorsh forming process as well as wind erosion caused gradual lowering of ground level. Depth of degraded peat layer in roof of surveyed peat deposits was between 0,2 and 0,8 m. Ground surface was lowering of 1,68 cm per year. It was found that, for ploughfields especially, peat-moorhs soil showing medium degree of moorsh forming process (MtII) and prognostic soil-moisture complex BC (periodically drying), after 17 years already, had changed into a soil with high degree of moorsh forming process (MtIII) and prognostic soil-moisture complex C (drying). For meadows and pastures land used such evident change wasn't noticed. During the whole investigation period (25 years) mean lowering of the peat-moorsh soils level along transects lines for different land use was: 1,15 cm per year for meadows and pastures, 1,58 cm pea year for plougfields and 1,38 cm per year for alder wood.

Polyphenols as enzyme inhibitors in different degraded peat soils: Implication for microbial metabolism in rewetted peatlands

NASA Astrophysics Data System (ADS)

Zak, Dominik; Roth, Cyril; Gelbrecht, Jörg; Fenner, Nathalie; Reuter, Hendrik

2015-04-01

Recently, more than 30,000 ha of drained minerotrophic peatlands (= fens) in NE Germany were rewetted to restore their ecological functions. Due to an extended drainage history, a re-establishment of their original state is not expected in the short-term. Elevated concentrations of dissolved organic carbon, ammonium and phosphate have been measured in the soil porewater of the upper degraded peat layers of rewetted fens at levels of one to three orders higher than the values in pristine systems; an indicator of increased microbial activity in the upper degraded soil layers. On the other hand there is evidence that the substrate availability within the degraded peat layer is lowered since the organic matter has formerly been subject to intense decomposition over the decades of drainage and intense agricultural use of the areas. Previously however, it was suggested that inhibition of hydrolytic enzymes by polyphenolic substances is suspended during aeration of peat soils mainly due to the decomposition of the inhibiting polyphenols by oxidising enzymes such as phenol oxidase. Accordingly we hypothesised a lack of enzyme inhibiting polyphenols in degraded peat soils of rewetted fens compared to less decomposed peat of more natural fens. We collected both peat samples at the soil surface (0-20 cm) and fresh roots of dominating vascular plants and mosses (as peat parent material) from five formerly drained rewetted sites and five more natural sites of NE Germany and NW Poland. Less decomposed peat and living roots were used to obtain an internal standard for polyphenol analysis and to run enzyme inhibition tests. For all samples we determined the total phenolic contents and in addition we distinguished between the contents of hydrolysable and condensed tannic substances. From a methodical perspective the advantage of internal standards compared to the commercially available standards cyanidin chloride and tannic acid became apparent. Quantification with cyanidin or tannic acid led to a considerable underestimation (up to 90%) of polyphenolic concentrations in peat soils. As hypothesised we found that highly degraded peat contains far lower levels of total polyphenolics (factor 8) and condensed tannins (factor 50) than less decomposed peat. In addition we detected large differences between different plant species with highest polyphenolic contents for the roots of Carex appropinquata that were more than 10-fold higher than Sphagnum spp. (450 mg/g dry mass vs. 39 mg/g dry mass). Despite these differences, we did not find a significant correlation between enzyme activities and peat degradation state, indicating that there is no simple linear relationship between polyphenolic contents and microbial activity.

CO2 Efflux from Cleared Mangrove Peat

PubMed Central

Lovelock, Catherine E.; Ruess, Roger W.; Feller, Ilka C.

2011-01-01

Background CO2 emissions from cleared mangrove areas may be substantial, increasing the costs of continued losses of these ecosystems, particularly in mangroves that have highly organic soils. Methodology/Principal Findings We measured CO2 efflux from mangrove soils that had been cleared for up to 20 years on the islands of Twin Cays, Belize. We also disturbed these cleared peat soils to assess what disturbance of soils after clearing may have on CO2 efflux. CO2 efflux from soils declines from time of clearing from ∼10 600 tonnes km−2 year−1 in the first year to 3000 tonnes km2 year−1 after 20 years since clearing. Disturbing peat leads to short term increases in CO2 efflux (27 umol m−2 s−1), but this had returned to baseline levels within 2 days. Conclusions/Significance Deforesting mangroves that grow on peat soils results in CO2 emissions that are comparable to rates estimated for peat collapse in other tropical ecosystems. Preventing deforestation presents an opportunity for countries to benefit from carbon payments for preservation of threatened carbon stocks. PMID:21738628

CO2 efflux from cleared mangrove peat.

PubMed

Lovelock, Catherine E; Ruess, Roger W; Feller, Ilka C

2011-01-01

CO(2) emissions from cleared mangrove areas may be substantial, increasing the costs of continued losses of these ecosystems, particularly in mangroves that have highly organic soils. We measured CO(2) efflux from mangrove soils that had been cleared for up to 20 years on the islands of Twin Cays, Belize. We also disturbed these cleared peat soils to assess what disturbance of soils after clearing may have on CO(2) efflux. CO(2) efflux from soils declines from time of clearing from ∼10,600 tonnes km(-2) year(-1) in the first year to 3000 tonnes km(2) year(-1) after 20 years since clearing. Disturbing peat leads to short term increases in CO(2) efflux (27 umol m(-2) s(-1)), but this had returned to baseline levels within 2 days. Deforesting mangroves that grow on peat soils results in CO(2) emissions that are comparable to rates estimated for peat collapse in other tropical ecosystems. Preventing deforestation presents an opportunity for countries to benefit from carbon payments for preservation of threatened carbon stocks.

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

NASA Astrophysics Data System (ADS)

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

2016-02-01

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

Effects of peat fires on the characteristics of humic acid extracted from peat soil in Central Kalimantan, Indonesia.

PubMed

Yustiawati; Kihara, Yusuke; Sazawa, Kazuto; Kuramitz, Hideki; Kurasaki, Masaaki; Saito, Takeshi; Hosokawa, Toshiyuki; Syawal, M Suhaemi; Wulandari, Linda; Hendri I; Tanaka, Shunitz

2015-02-01

When peat forest fires happen, it leads to burn soil and also humic acids as a dominant organic matter contained in peat soil as well as the forest. The structure and properties of humic acids vary depending on their origin and environment, therefore the transformation of humic acid is also diverse. The impacts of the peat fires on peat soil from Central Kalimantan, Indonesia were investigated through the characterization of humic acids, extracted from soil in burnt and unburnt sites. The characterization of humic acids was performed by elemental composition, functional groups, molecular weight by HPSEC, pyrolysate compounds by pyrolysis-GC/MS, fluorescence spectrum by 3DEEM spectrofluorometer, and thermogravimetry. The elemental composition of each humic substance indicated that the value of H/C and O/C of humic acids from burnt sites were lower than that from unburnt sites. The molecular weight of humic acids from burnt sites was also lower than that from unburnt sites. Pyrolysate compounds of humic acids from unburnt sites differed from those of humic acids from burnt soil. The heating experiment showed that burning process caused the significant change in the properties of humic acids such as increasing the aromaticity and decreasing the molecular weight.

Performance assessment and parameterization of the SWAP-WOFOST model for peat soil under agricultural use in northern Europe.

NASA Astrophysics Data System (ADS)

Bertram, Sascha; Bechtold, Michel; Hendriks, Rob; Piayda, Arndt; Regina, Kristiina; Myllys, Merja; Tiemeyer, Bärbel

2017-04-01

Peat soils form a major share of soil suitable for agriculture in northern Europe. Successful agricultural production depends on hydrological and pedological conditions, local climate and agricultural management. Climate change impact assessment on food production and development of mitigation and adaptation strategies require reliable yield forecasts under given emission scenarios. Coupled soil hydrology - crop growth models, driven by regionalized future climate scenarios are a valuable tool and widely used for this purpose. Parameterization on local peat soil conditions and crop breed or grassland specie performance, however, remains a major challenge. The subject of this study is to evaluate the performance and sensitivity of the SWAP-WOFOST coupled soil hydrology and plant growth model with respect to the application on peat soils under different regional conditions across northern Europe. Further, the parameterization of region-specific crop and grass species is discussed. First results of the model application and parameterization at deep peat sites in southern Finland are presented. The model performed very well in reproducing two years of observed, daily ground water level data on four hydrologically contrasting sites. Naturally dry and wet sites could be modelled with the same performance as sites with active water table management by regulated drains in order to improve peat conservation. A simultaneous multi-site calibration scheme was used to estimate plant growth parameters of the local oat breed. Cross-site validation of the modelled yields against two years of observations proved the robustness of the chosen parameter set and gave no indication of possible overparameterization. This study proves the suitability of the coupled SWAP-WOFOST model for the prediction of crop yields and water table dynamics of peat soils in agricultural use under given climate conditions.

Comparisons of soil nitrogen mass balances for an ...

EPA Pesticide Factsheets

We compared the N budgets of an ombrotrophic bog and a minerotrophic fen to quantify the importance of denitrification in peatlands and their watersheds. We also compared the watershed upland mineral soils to bog/fen peat; lagg and transition zone peat to central bog/fen peat; and surface, mid-layer and deep soil and peat horizons. Bog and fen area were derived from a wetland boundary GIS data layer, and bog and fen volumes were calculated as the interpolated product of area and depth of peat. Atmospheric N deposition to the bog and fen were based on measurements from a station located 2km north of the bog watershed and 0.5km from the fen watershed. Precipitation was analyzed for nitrate (NO3-), ammonium (NH4+), and total N (TN), and aggregated to annual values. Outflow water samples from the bog and fen were collected as surface grab samples on each of the May-October sampling dates over the 2010-2013 study, and were analyzed and aggregated annually as for atmospheric N. Soil and peat samples were analyzed for N content, and for net ammonification (AM), nitrification (NT), and ambient (DN) and potential (DEA) denitrification rates. Nitrogen mass balances are based on mean annual atmospheric deposition and outflow; soil and peat standing stocks of N, and mean annual estimates of DN, weighted for contributions of the uplands, lagg or transition zone, and bog or fen hollows and hummocks, and accounting for soil depth effects. Annual deposition of N species was: N

Effects of soil temperature, flooding, and organic matter addition on N2O emissions from a soil of Hongze Lake wetland, China.

PubMed

Lu, Yan; Xu, Hongwen

2014-01-01

The objectives of this study were to test the effects of soil temperature, flooding, and raw organic matter input on N2O emissions in a soil sampled at Hongze Lake wetland, Jiangsu Province, China. The treatments studied were-peat soil (I), peat soil under flooding (II), peat soil plus raw organic matter (III), and peat soil under flooding plus organic matter. These four treatments were incubated at 20°C and 35°C. The result showed that temperature increase could enhance N2O emissions rate and cumulative emissions significantly; moreover, the flooded soil with external organic matter inputs showed the lowest cumulative rise in N2O emissions due to temperature increment. Flooding might inhibit soil N2O emissions, and the inhibition was more pronounced after organic matter addition to the original soil. Conversely, organic matter input explained lower cumulative N2O emissions under flooding. Our results suggest that complex interactions between flooding and other environmental factors might appear in soil N2O emissions. Further studies are needed to understand potential synergies or antagonisms between environmental factors that control N2O emissions in wetland soils.

Function of peatland located on secondary transformed peat-moorsh soils on groundwater purification processes and the elution of soil organic matter

NASA Astrophysics Data System (ADS)

Szczepański, M.; Szajdak, L.; Bogacz, A.

2009-04-01

The investigation of peatland is used to show the water quality functioning with respect to different forms of nitrogen and carbon. The purification of ground water by the transect of 4.5 km long consisting organic soils (peat-moorsh soils) was estimated. This transect is located in the Agroecological Landscape Park in Turew, 40 km South-West of Poznan, West Polish Lowland. There is this transect along Wyskoć ditch. pH, the contents of total and dissolved organic carbon, total nitrogen, N-NO3-, N-NH4+ was measured. Additionally C/N factors of peats were estimated. The investigation has shown the impact of the peatland located on the secondary transformed peat - moorsh soils on the lowering of total nitrogen, ammonium, and nitrates as well as total and dissolved organic carbon in ground water. Peat-moorsh soils were described and classified according to Polish hydrogenic soil classification and World Reference Base Soil Notation. There are these investigated points along to Wyskoc ditch. Two times a month during entire vegetation season the following material was taken from four chosen sites marked as Zbechy, Bridge, Shelterbelt and Hirudo: samples of peat, from the depth of 0-20 cm, samples of water from the ditch, samples of ground water from wells established for this investigation. Samples of peat-moorsh soils were collected at the depth 0-20 cm. Soils were sampled two times a month from 10 sites of each site. Samples were air dried and crushed to pass a 1 mm-mesh sieve. These 10 sub-samples were mixed for the reason of preparing a "mean sample", which used for the determination of pH (in 1M KCl), dissolved organic carbon (DOC), total organic carbon (TOC), total nitrogen (Ntotal), and N-NO3- as well as N-NH4+. In water from Wyskoć ditch pH, Ntotal, N-NO3-, N-NH4+, DTC (dissolved total carbon) and DOC (dissolved organic carbon) was measured. Ground water samples were collected from four wells established for this investigation. The water was filtered by the middle velocity separation and pH, N-total, N-NO3-, N-NH4+, DTC (dissolved total carbon) and DOC (dissolved organic carbon) ware measured. Peatland located on the secondary transformed peat - moorsh soils has revealed the lowering in ground water: nitrates 38.5%, N-organic 10%, N-total 24.5%, ammonium 38.7%, dissolved total carbon 33.1%, dissolved total inorganic carbon 10%, and dissolved organic carbon 57.5%. The dissolution of soil organic matter from peat-moorsh soils in broad range of pH and ionic strength was investigated. The rates of the reaction were calculated from the kinetics of first order reaction model. The investigations have shown the impact of the properties of secondary transformed peat-moorsh soils on the rates of the dissolution of organic matter.

Comparison of Shear Strength Properties for Undisturbed and Reconstituted Parit Nipah Peat, Johor

NASA Astrophysics Data System (ADS)

Azhar, A. T. S.; Norhaliza, W.; Ismail, B.; Abdullah, M. E.; Zakaria, M. N.

2016-11-01

Shear strength of soil is required to determine the soil stability and design the foundations. Peat is known as a soil with complex natural formations which also contributes problems to the researchers, developers, engineers and contractors in constructions and infrastructures. Most researchers conducted experiment and investigation of shear strength on peat using shear box test and simple shear test, but only a few had discovered the behavior of peat using triaxial consolidated undrained test. The aim of this paper is to determine the undrained shear strength properties of reconstituted peat and undisturbed peat of Parit Nipah, Johor for comparison purposes. All the reconstituted peat samples were formed with the size that passed opening sieve 3.35 mm and preconsolidation pressure at 100 kPa. The result of undrained shear strength of reconstituted peat was 21kPa for cohesion with the angle of friction, 41° compare to the undisturbed peat with cohesion 10 kPa and angle of friction, 16°. The undrained shear strength properties result obtained shows that the reconstituted peat has higher strength than undisturbed peat. For relationship deviator stress-strain, σd max and excess pore pressure, Δu, it shows that both of undisturbed and reconstituted gradually increased when σ’ increased, but at the end of the test, the values are slightly dropped. The physical properties of undisturbed and reconstituted peat were also investigated to correlate with the undrained shear strength results.

Biogeochemistry of carbon and related major and trace elements in peat bog soils of the middle taiga of Western Siberia (Russia).

NASA Astrophysics Data System (ADS)

Stepanova, V. A.; Mironycheva-Tokareva, N. P.; Pokrovsky, O. S.

2012-04-01

Global climate changes impact the status of wetland ecosystems shifting the balances of the carbon, macro-, and microelements cycles. This study aims to establish the features of accumulation and distribution of major- and trace elements in the organic layer of peat bog soils, belonging to different ecosystems of the oligotrophic bog complex located in the middle taiga of Western Siberia (Khanty-Mansiysk region, Russia). Key areas which are selected for this study include the following bog conjugate elementary ecosystems: higher ryam, lower ryam, ridge-hollow complex, and oligotrophic poor fen as characterized previously [1]. We have sampled various peat types along the entire length of the soil column (every 10 cm down to 3 m). Peat samples were analyzed for a wide range of macro- and microelements using an ICP-MS technique following full acid digestion in a microwave oven. These measurements allowed quantitative estimates of major- and trace elements in the peat deposits within the whole bog complex and individual elementary landscapes. Based on the data obtained, the lateral and radial geochemical structures of the bog landscapes were determined and clarified for the first time for middle taiga of the West Siberian plain. The similar regime of mineral nutrition during the complete bog landscape formation was detected for the peat deposits based on the measurements of some major- and trace elements (Ca, Fe, Mg, etc.). The vertical distribution of some major and some trace elements along the profile of peat column is rather uniform with relatively strong increase in the bottom organic layers. This strongly suggests the similarity of the processes of element accumulation in the peat and relatively weak post depositional redistribution of elements within the peat soil profile. Overall, obtained corroborate the existing view on chemical composition of peats being determined by botanical peat's components (which forms this peat deposit), atmospheric precipitation, position of ecosystems in the landscape (lateral migration) and types of bedrocks [2]. The results allow better understanding of the coupling between biogeochemical cycles of carbon and major and trace elements in peat soils in order to predict the future changes in both concentrations and stocks of chemical elements in the Western Siberia peat bog systems under climate warming.

Thermomagnetic properties of peat-soil layers from Sag pond near Lembang Fault, West Java, Indonesia

NASA Astrophysics Data System (ADS)

Iryanti, Mimin; Wibowo, Dimas Maulana; Bijaksana, Satria

2015-09-01

Sag pond is a body of water near fault system as water flows blocked by the fault. Sag pond is a special type of environment for peat formation as peat layers in were deposited as the fault moves in episodic fashion. Depending on the history of the fault, peat layers are often interrupted by soil layers. In this study, core of peat-soil layers from a Sag pond in Karyawangi Village near Lembang Fault was obtained and analyzed for its magnetic properties. The 5 m core was obtained using a hand auger. Individual samples were obtained every cm and measured for their magnetic susceptibility. In general, there are three distinct magnetic susceptibility layers that were associated with peat and soil layers. The upper first 1 m is unconsolidated mud layer with its relatively high magnetic susceptibility. Between 1-2.81 m, there is consolidated mud layer and the lowest part (2.82-5) m is basically peat layer. Six samples were then measured for their thermomagnetic properties by measuring their susceptibility during heating and cooling from room temperature to 700°C. The thermomagnetic profiles provide Curie temperatures for various magnetic minerals in the cores. It was found that the upper part (unconsolidated mud) contains predominantly iron-oxides, such as magnetite while the lowest part (peat layer) contains significant amount of iron-sulphides, presumably greigite.

Persistent high temperature and low precipitation reduce peat carbon accumulation.

PubMed

Bragazza, Luca; Buttler, Alexandre; Robroek, Bjorn J M; Albrecht, Remy; Zaccone, Claudio; Jassey, Vincent E J; Signarbieux, Constant

2016-12-01

Extreme climate events are predicted to become more frequent and intense. Their ecological impacts, particularly on carbon cycling, can differ in relation to ecosystem sensitivity. Peatlands, being characterized by peat accumulation under waterlogged conditions, can be particularly sensitive to climate extremes if the climate event increases soil oxygenation. However, a mechanistic understanding of peatland responses to persistent climate extremes is still lacking, particularly in terms of aboveground-belowground feedback. Here, we present the results of a transplantation experiment of peat mesocosms from high to low altitude in order to simulate, during 3 years, a mean annual temperature c. 5 °C higher and a mean annual precipitation c. 60% lower. Specifically, we aim at understanding the intensity of changes for a set of biogeochemical processes and their feedback on carbon accumulation. In the transplanted mesocosms, plant productivity showed a species-specific response depending on plant growth forms, with a significant decrease (c. 60%) in peat moss productivity. Soil respiration almost doubled and Q 10 halved in the transplanted mesocosms in combination with an increase in activity of soil enzymes. Spectroscopic characterization of peat chemistry in the transplanted mesocosms confirmed the deepening of soil oxygenation which, in turn, stimulated microbial decomposition. After 3 years, soil carbon stock increased only in the control mesocosms whereas a reduction in mean annual carbon accumulation of c. 30% was observed in the transplanted mesocosms. Based on the above information, a structural equation model was built to provide a mechanistic understanding of the causal connections between peat moisture, vegetation response, soil respiration and carbon accumulation. This study identifies, in the feedback between plant and microbial responses, the primary pathways explaining the reduction in carbon accumulation in response to recurring climate extremes in peat soils. © 2016 John Wiley & Sons Ltd.

Hydrological controls on rate of organic matter mineralization in peats

NASA Astrophysics Data System (ADS)

Ghezzehei, Teamrat; Arnold, Chelsea; Asefaw Berhe, Asmeret

2016-04-01

The predominant factor that ties together the formation and persistence of peat soils across regions is their dependence on localized hydrology. Hydrology also plays a dominant role in the relative strength of peatlands as sinks for atmospheric carbon dioxide and sources of methane, and thus on peatland net climate impact. Drying of peat soils by climate change and/or drainage is typically followed by reduction in methane emissions. However, this may easily be offset by the increase in carbon dioxide production. Therefore, mechanistic understanding of peatland hydrology and its association with carbon cycling is a prerequisite for assessing vulnerability of peats to disturbances and for incorporating the associated feedbacks in carbon-climate models. We will present physically based model that ties together the structure of peat soils (mainly pore size distribution and mechanical stability) to rates of aerobic and anaerobic decomposition over a wide range of soil water potentials. Peats consist of hierarchical structure with clear separation of the pores into a population of micropores within clumps of organic matter and/or soil aggregates and a group of macropores between clumps and/or aggregates. This essentially partitions the carbon stock in peat soils in to multiple pools that become mineralizable at disparate water potential ranges. While the carbon in macropores can readily be decomposed by aerobic microorganisms when the soil is only slightly drained, the carbon in fine pores remains largely protected from aerobic microbes until the water potential exceeds a threshold that lets in oxygen. In this presentation we will show the mathematical development of the model and illustrative examples that compare projections with data derived from the literature.

Selected Trace Element Concentrations in Peat Used for Cosmetic Production - A Case Study from Southern Poland

NASA Astrophysics Data System (ADS)

Glina, Bartłomiej

2016-12-01

The aim of the study was to assess the concentration of selected trace elements in organic soils used as a source to obtain a unique peat extract for cosmetics production. Peat material for laboratory analysis were collected from fen peatland located in the Prosna River Valley (Borek village). Studied peatland is managed by "Torf Corporation" company as a source of material to obtain peat extract for cosmetics production. In the collected soil samples (four soil profiles) Zn, Cu and Pb concentrations were determined by using atomic absorption spectrometer SpectraAA 220 (Varian), after acid digestion. Obtained results showed that the highest concentrations of selected trace elements were recorded in the surface horizons of organic soils. This fact might be the results of Prosna river flooding or air deposition. Howevere, according to the new Polish regulations (Ordinance of the Minister for Environment 01.09.2016 - the way of conducting contamination assessment of the earth surface), the content of trace elements in the examined soils was greatly belowe the permissible limit for areas from group IV (mine lands). Thus, described soils are proper to obtain peat extract used as a component in cosmetic production.

Does Miscanthus cultivation on organic soils compensate for carbon loss from peat oxidation? A dual label study

NASA Astrophysics Data System (ADS)

Bader, Cédric; Leifeld, Jens; Müller, Moritz; Schulin, Rainer

2016-04-01

Agricultural use of organic soils requires drainage and thereby changes conditions in these soils from anoxic to oxic. As a consequence, organic carbon that had been accumulated over millennia is rapidly mineralized, so that these soils are converted from a CO2 sink to a source. The peat mineralization rate depends mainly on drainage depth, but also on crop type. Various studies show that Miscanthus, a C4 bioenergy plant, shows potential for carbon sequestration in mineral soils because of its high productivity, its dense root system, absence of tillage and high preharvest litterfall. If Miscanthus cropping would have a similar effect in organic soils, peat consumption and thus CO2 emissions might be reduced. For our study we compared two adjacent fields, on which organic soil is cultivated with Miscanthus (since 20 years) and perennial grass (since 6 years). Both sites are located in the Bernese Seeland, the largest former peatland area of Switzerland. To determine wether Miscanthus-derived carbon accumulated in the organic soil, we compared the stable carbon isotopic signatures of the experimental soil with those of an organic soil without any C4-plant cultivation history. To analyze the effect of C4-C accumulation on peat degradability we compared the CO2 emissions by incubating 90 soil samples of the two fields for more than one year. Additionally, we analysed the isotopic CO2 composition (13C, 14C) during the first 25 days of incubation after trapping the emitted CO2 in NaOH and precipitating it as BaCO3. The ∂13C values of the soil imply, that the highest share of C4-C of around 30% is situated at a depth of 10-20 cm. Corn that used to be cultivated on the grassland field before 2009 still accounts for 8% of SOC. O/C and H/C ratios of the peat samples indicate a stronger microbial imprint of organic matter under Miscanthus cultivation. The amount of CO2 emitted was not affected by the cultivation type. On average 57% of the CO2 was C4 derived in the Miscanthus field, whereas 38% was C4-derived in the Grassland field. According to our radiocarbon data, 38% of the CO2 must have originated from peat-derived OM on the Miscanthus field, whereas 57% of the CO2 was derived from peat in the grassland. Although peat minerlaization seems to be smaller and a significant amount of C4-C accumulated under Miscanthus, peat mineralization nonetheless contributed substantially to soil respiration. Together, our data do not support the hypothesis that Miscanthus cultivation can fully compensate for organic matter loss in drained peatlands.

Comparisons of soil nitrogen mass balances for an ombrotrophic bog and a minerotrophic fen in northern Minnesota

EPA Science Inventory

We compared the N budgets of an ombrotrophic bog and a minerotrophic fen to quantify the importance of denitrification in peatlands and their watersheds. We also compared the watershed upland mineral soils to bog/fen peat; lagg and transition zone peat to central bog/fen peat; an...

Soils of peatlands: histosols and gelisols

Treesearch

Randy Kolka; Scott D. Bridgham; Chien-Lu Ping

2016-01-01

Peatlands are a subset of wetlands that have accumulated significant amounts of soil organic matter. Soils of peatlands are colloquially known as peat, with mucks referring to peats that are decomposed to the point that the original plant remains are altered beyond recognition (Chapter 6, SSSA 2008). Generally, soils with a surface organic layer >40 cm thick...

Quantifying the impacts of land use change on soil organic carbon losses in tropical peatlands

NASA Astrophysics Data System (ADS)

Farmer, J.; Smith, J.; Smith, P.; Matthews, R.

2012-04-01

The challenge of collecting field measurements of soil carbon dioxide (CO2) efflux and soil carbon (C) in tropical peatlands creates an opportunity for the use of SOC models for predicting local and regional impacts of land use and climate change on these soils, offering a way of translating this limited data into tangible results. Previously, no soil C model existed for use in non-steady state sites such as those found on tropical peats- in particular peat swamp forests which accumulate C, and oil palm plantations which are grown for 20-25 years between re-plantings. A simple, user friendly model has been created for use by scientists, policy makers and plantation managers. This model uses only limited inputs to predict the changes to soil C from land use and climate change. The model runs on the assumption that plant inputs can be related to yield, and that this can be used to derive the decomposition of SOM. It uses a simple decomposition response to determine the changes to the soil C. The model can run in a basic form if data is very limited, or a more complex form with modifiers for temperature, pH, salinity and soil moisture if this data is available. Using measured CO2 efflux and soil C values from peat cores, combined with literature values, we demonstrate the efficacy of the model, showing how we have identified and addressed some of the issues related to modelling soil C losses from tropical peat soils under land use change. Key challenges addressed included quantifying the effects of drainage when peat swamp forests are converted to oil palm plantations, and comparing field results between sites because in oil palm plantations the original soil conditions prior to conversion from peat swamp forest were largely unknown.

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

USGS Publications Warehouse

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

2012-01-01

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

Influence of forest management on the changes of organic soil properties in border part of Kragle Mokradlo Peatland (Stolowe Mountains National Park, Poland)

NASA Astrophysics Data System (ADS)

Bogacz, A.; Roszkowicz, M.

2009-04-01

SUMMARY The aim of this work was to determine the properties of organic soils modified by man, muddy and fluvial process. Peat horizons were analyzed and classified by types - and species of peat. Three profiles of shallow peat and peaty gley soils identified. Investigation showed that organic soil developed on a sandy weathered sandstone base according to oligotrophic type of sites. Organic horizons were mixed with sand and separated by sandy layers. Those soils were classified as Sapric Histosols Dystric or Sapric Gleysols Histic (WRB 2006). The throphism of organic soil in this object resulted from both natural factors and anthropo-pedogenesis. key words: peat deposit, organic soils, soil properties, muddy process, sandy layers INTRODUCTION The areas of Stolowe Mountains National Park were influenced by forestry management. Many peatlands in the Park area were drained for forestry before World War II. Several amelioration attempts were undertaken as early as in the nineteenth century. The system of forest roads were built on drained areas. The Kragle Mokradlo Peatland is located in the Skalniak plateau. The object is cut by a melioration ditch. This ditch has been recently blocked to rewet the objects. Several forest roads pass in the close neighbourhood of investigated areas. In a border part of Kragle Mokradlo Peatlands, we can observe artificial spruce habitat. Investigated object represents shallow peat soil developed on sandy basement. The early investigations showed that peaty soils were also covered by sandstone - related deposits, several dozen centimeter thick (BOGACZ 2000). Those layers was developed from sandstone weathered material transported by wind and water. The aim of presented works was to determine the stage of evolution of organic soils on the base on their morphological, physical and chemical properties. MATERIAL AND METHODS Peat soils in different locations (3 profiles, 18 samples) were selected for examination. Peat samples were collected from study areas using a 6.0 cm diameter Instorfu peat auger (HORAWSKI 1987). Soil horizons were determined on the basis of colour, degree of organic matter decomposition and the quality of vegetation remains. Cores were taken to the depth where underlying mineral material was encountered. The cores ware sectioned to subsamples at intervals at major stratigrafic breaks. Some physical, chemical properties and botanical composition of peat were determined in this material. Differentiation in botanical composition of peat was analyzed by the microscopic method and subsequently classified according to the Polish standards (Oznaczanie gatunku...1977). Peat humification degree was measured using two methods: SPEC method and half syringe method (LYNN at all. 1974). Ash content was estimated by combusting the material in a muffle furnace at 500oC for 4 hours. The texture of mineral horizons was determined using the Bouyoucos hydrometer method (GEE AND BOUNDER 1986). The specific gravity (W) and bulk density (Z) of organic soils were calculated using the following formula's (ZAWADZKI 1970): W=0.11A+1.451, (1.451) represents the specific gravity of humus, Z =0.004A+0.0913, A is a ash content and constant (0.0913) represents the bulk density of humus. The following chemical properties of organic soil horizons were analyzed: content of total carbon and nitrogen, acidity in H2O and 1mol dm-3 KCl and CECe in CH3COONH4 at pH 7. Base saturation (BS) of soil sorption complex was calculated. The soils were classified to reference groups in WRB Classification System (WRB 2006). RESULTS AND DISSCUSION Based on the cores, -the soils in the border part of Kragle Mokradlo Peatland area were classified as Sapric Histosols Dystric or Sapric Gleysols Histic (WRB 2006). Soils represented ombrogenic type of hydrological conditions. In that site, an ombrogenic type of hydrological input is the predominant mechanism of soil evolution. Soil examined in this study have developed in oligotrophic type of site. Organic soils developed on sandy weathered sandstones. The depth of organic horizons ranged from 40 to 80 cm. The object represented spruce forests habitat introduced by man. Organic horizons were separated by sandy layers. The process of sandstone weathering and forestry management changed morphological features of soils. Presently, the area is under the influence of fluvigenic type of hydrological input, too. Geobotanical analyses of peat layers indicated significant presence of preserved fragments of roots grasses, Sphagnum sp. and Bryales sp. Hemic or sapric material were usually present in organic horizons of this object. Analysis of organic horizons showed that their specific gravity was about 1.58-2.25 g cm-3, the bulk density was 0.14-0.42 g cm-3. The total porosity was in the range 82.0-91.1% and the ash content: in the range 11.74-77.96% of soil dry matter. Organic material consisting of weathered sandstone was likely to move down the profiles, increasing the concentration of sand and silt fractions in organic horizons. The similar phenomenon of residual deposits was reported by KLEMENTOWSKI (1979). The values of bulk density of peatland soils are connected with the high ash content. Ash content was different in situated layers. This is caused by the muddy and fluvial process. This situation was influenced by trophical status of this soils. The pH of sand and peat layers in a border part of Krągłe Mokradło Peatland was strongly acidic: pH H2O 2.92-3.51, pH KCl 2.38-3.07. The acidity was lower in upper horizons than in deeper ones. The ratio C/N in organic horizons ranged between 10:1 to 40:1. Low ratios of C/N in some upper horizons were probably caused by strong mineralization of organic matter. Strongly acidic soil horizons usually exhibited high cation exchange capacity (CECe). In general, the base saturated (BS) did not exceed 50%. Organic surface horizons showed higher content of potassium, calcium and magnesium than lower horizons. CONCLUSIONS Shallow organic soils occupy the ombrotrophic sites of a border part of Kragle Mokradlo Peatland. The variety of organic soil throphism in the object resulted from the placement on the base sandstone, partial mixing of soil horizons as well as from muddy and fluvial processes. Peat horizons present in the studied profiles were generally classified as hemic and sapric, sometimes as fibric. Soil horizons exhibited differed thickness and ash content. Forest management strongly changed the properties of organic soil. REFERENCES Bogacz, A. (2000). Physical properties of organic soil in Stolowe Mountains National Park (Poland). Suo 51,3; pp.105-113. Gee, G.W. and Bauder, J.W. (1986). Particle-size analysis. In: Klute, A.(ed.) Methods of Soil Analysis Part I. Agronomy series No. 9. Am. Soc. Agronomy Soil Sci. Am, Inc., Publ., Madison, WI.pp. 383-411. Horawski, M. (1987). Torfoznawstwo dla meliorantow. Pojecia podstawowe.[Peat science for melioration. Basic definitions.]. Wydawnictwo Akademii Rolniczej w Krakowie. pp.37-39.[In Polish]. Lubliner - Mianowska, K. (1951). Wskazowki do badania torfu. Metody geobotaniczne, polowe i laboratoryjne [Hints to peat research. In: Geobotanical, field and laboratory methods] Państwowe Wydawnictwo Techniczne, Katowice.pp.58-60. [In Polish]. Lynn, W.C., Mc Kinzie, W.E., Grossman, R.B. (1974). Field Laboratory Test for characterization of Histosols. In: Histosols, their characteristics, classification and use. pp. 11-20. Oznaczanie gatunku, rodzaju i typu torfu. (1977). [Peat and peat varies. Determination of classes, sort and types of peat]. Polish standard PN-76/G-02501, [Polish Normalization Commitee]. pp.1-11.[In Polish]. Word Reference Base for Soil Resources. 1998. Word Soil Resources Report, 84. FAO-ISRIC-ISSS, Rome, pp.1-88. Zawadzki, S. (1970). Relationship between the content of organic matter and physical properties of hydrogenic soils. Polish Journal of Soil Science Vol.III, 1; pp.3-9.

Conservation of peat soils in agricultural use by infiltration of ditch water via submerged drains: results of a case study in the western peat soil area of The Netherlands

NASA Astrophysics Data System (ADS)

van den Akker, Jan J. H.; Hendriks, Rob F. A.

2017-04-01

About 8% of all soils in The Netherlands are peat soils which almost all drained with ditches and mainly in agricultural use as permanent pasture for dairy farming. The largest part of the peat meadow area is situated in the densely populated western provinces South- and North-Holland and Utrecht and is called the Green Heart and is valued as a historic open landscape. Conservation of these peats soil by raising water levels and converting the peat meadow areas mainly in very extensive grasslands or wet nature proved to be a very costly and slow process due to the strong opposition of farmers and many others who value the open cultural historic landscape and meadow birds. The use of submerged drains seems to be a promising solution acceptable for dairy farmers and effective in diminishing peat oxidation and so the associated subsidence and CO2 emissions. Oxidation of peat soils strongly depends on the depth of groundwater levels in dry periods. In dry periods the groundwater level can be 30 to 50 cm lower than the ditchwater level, which is 30 - 60 cm below soil surface. Infiltration of ditchwater via submerged drain can raise the groundwater level up to the ditchwater level and diminish the oxidation and associated subsidence and CO2 emissions with at least 50%. Since 2003 several pilots with submerged drains are started to check this theoretical reduction and to answer questions raised about water usage and water quality and grass yields and trafficability etcetera. In our presentation we focus on the results of a pilot in South-Holland concerning the hydrological aspects, however, include results from the other pilots to consider the long term aspects such as the reduction of subsidence. The use of submerged drains proves to be promising to reduce peat oxidation and so subsidence and CO2 emissions with at least 50%. Grass yields are more or less equal in parcels with versus parcels without submerged drains. Trafficability in wet periods is better and trampling less by the draining effect of submerged drains. This reduces losses of grass yield by trampling and increases the length of the grazing season. The use of submerged drains causes a higher water usage, however, raising ditchwater levels to derive the same peat soil conservation would require a higher amount of inlet water. The impact on ditchwater quality is in most cases positive, however, sometimes slightly negative. For the dairy farmer submerged drains are economically in the short term not effective, however in the longer term increasingly positive. For the society as a whole the use of submerged drains is a very cost effective way to reduce CO2 emissions and subsidence of peat soils in agricultural use.

Soil carbon dioxide emissions from a rubber plantation on tropical peat.

PubMed

Wakhid, Nur; Hirano, Takashi; Okimoto, Yosuke; Nurzakiah, Siti; Nursyamsi, Dedi

2017-03-01

Land-use change in tropical peatland potentially results in a large amount of carbon dioxide (CO 2 ) emissions owing to drainage, which lowers groundwater level (GWL) and consequently enhances oxidative peat decomposition. However, field information on carbon balance is lacking for rubber plantations, which are expanding into Indonesia's peatlands. To assess soil CO 2 emissions from an eight-year-old rubber plantation established on peat after compaction, soil CO 2 efflux was measured monthly using a closed chamber system from December 2014 to December 2015, in which a strong El Niño event occurred, and consequently GWL lowered deeply. Total soil respiration (SR) and oxidative peat decomposition (PD) were separately quantified by trenching. In addition, peat surface elevation was measured to determine annual subsidence along with GWL. With GWL, SR showed a negative logarithmic relationship (p<0.01), whereas PD showed a strong negative linearity (p<0.001). Using the significant relationships, annual SR and PD were calculated from hourly GWL data to be 3293±1039 and 1408±214gCm -2 yr -1 (mean±1 standard deviation), respectively. PD accounted for 43% of SR on an annual basis. SR showed no significant difference between near and far positions from rubber trees (p>0.05). Peat surface elevation varied seasonally in almost parallel with GWL. After correcting for GWL difference, annual total subsidence was determined at 5.64±3.20 and 5.96±0.43cmyr -1 outside and inside the trenching, respectively. Annual subsidence only through peat oxidation that was calculated from the annual PD, peat bulk density and peat carbon content was 1.50cmyr -1 . As a result, oxidative peat decomposition accounted for 25% of total subsidence (5.96cmyr -1 ) on average on an annual basis. The contribution of peat oxidation was lower than those of previous studies probably because of compaction through land preparation. Copyright © 2017 Elsevier B.V. All rights reserved.

Dissolved organic carbon in soil solution of peat-moorsh soils on Kuwasy Mire

NASA Astrophysics Data System (ADS)

Jaszczyński, J.; Sapek, A.

2009-04-01

Key words: peat-moorsh soils, soil solution, dissolved organic carbon (DOC), temperature of soil, redox potential. The objective this study was the dissolved organic carbon concentration (DOC) in soil solution on the background of soil temperature, moisture and redox potential. The investigations were localized on the area of drained and agricultural used Kuwasy Mire, which are situated in the middle basin of Biebrza River, in North-East Poland. Research point was placed on a low peat soil of 110 cm depth managed as extensive grassland. The soil was recognized as peat-moorsh with the second degree of the moorshing process (with 20 cm of moorsh layer). The ceramic suction cups were installed in three replications at 30 cm depth of soil profile. The soil solution was continuously sampled by pomp of the automatic field station. The successive samples comprised of solution collected at the intervals of 21 days. Simultaneously, at the 20, 30 and 40 cm soil depths the measurements of temperature and determination of soil moisture and redox potential were made automatically. The mean twenty-four hours data were collected. The concentrations of DOC were determined by means of the flow colorimeter using the Skalar standard methods. Presented observations were made in 2001-2006. Mean DOC concentration in soil solution was 66 mg.dm-3 within all research period. A significant positive correlation between studied compound concentration and temperature of soil at 30 cm depth was observed; (correlation coefficient - r=0.55, number of samples - n=87). The highest DOC concentrations were observed during the season from July to October, when also a lower ground water level occurred. The DOC concentration in soil solution showed as well a significant correlation with the soil redox potential at 20 cm level. On this depth of describing soil profile a frontier layer between moorshing layer and peat has been existed. This layer is the potentially most active in the respect to biochemical transformation. On the other hand it wasn't possible to shown dependences on the DOC concentration from soil moisture. That probably results from a huge water-holding capacity of these type of peat soils, which are keeping a high moisture content even at a long time after decreasing of the groundwater table.

Methane and CO2 fluxes from peat soil, palm stems and field drains in two oil palm plantations in Sarawak, Borneo, on different tropical peat soil types.

NASA Astrophysics Data System (ADS)

Manning, Frances; Lip Khoon, Kho; Hill, Tim; Arn Teh, Yit

2017-04-01

Oil palm plantations have been expanding rapidly on tropical peat soils in the last 20 years, with 50 % of SE Asian peatlands now managed as industrial or small-holder plantations, up from 11% in 1990. Tropical peat soils are an important carbon (C) store, containing an estimated 17 % of total peatland C. There are large uncertainties as to the soil C dynamics in oil palm plantations on peat due to a shortage of available data. It is therefore essential to understand the soil C cycle in order to promote effective management strategies that optimise yields, whilst maintaining the high C storage capacity of the soil. Here we present CO2 and CH4 fluxes from two oil palm plantations in Sarawak, Malaysia on peat soils. Data were collected from different surface microforms within each plantation that experienced different surface management practices. These included the area next to the palm, in bare soil harvest paths, beneath frond piles, underneath cover crops, from the surface of drains, and from palm stems. Data were collected continuously over one year and analysed with different environmental variables, including soil temperature, WTD, O2, soil moisture and weather data in order to best determine the constraints on the dataset. Total soil respiration (Rtot) varied between 0.09 and 1.59 g C m-2 hr-1. The largest fluxes (0.59 - 1.59 g C m-2 hr-1) were measured next to the palms. Larger CO2 fluxes were observed beneath the cover crops than in the bare soil. This trend was attributed to priming effects from the input of fresh plant litter and exudates. Peat soil type was shown to have significantly different fluxes. The different plantations also had different environmental drivers best explaining the variation in Rtot - with soil moisture being the most significant variable on Sabaju series soil and soil temperature being the most significant environmental variable in the plantation with the Teraja series soil. Rtot was shown to reduce significantly with increasing distance from the palm. The relationship between Rtot and root biomass, which also decreased significantly with increasing distance from the palm, allowed for the partitioning of Rtot into peat oxidation and Ra. Here rates of peat oxidation were estimated to be 0.11 g C m-2 hr-1 following partitioning, and 0.16 g C m-2 hr-1 without partitioning. Methane fluxes varied between 0 and 1.95 g C m-2 hr-1. The largest methane fluxes were emitted from collection drains. Methane oxidation was occasionally observed in field drains, when the water table dropped below the depth of the drain. Soil methane fluxes were lower than those from collection drains. The highest methane fluxes were observed next to palms (0.02 mg C m-2 hr-1) and the lowest under frond piles (0.08 mg C m-2 hr-1). Methane emissions were measured from the palm stems. Preliminary data gives a range between 0.005 and 0.27 µg C m-2 hr-1. These results show wide ranges in both CO2 and CH4 emissions from different sources within the plantations, with the collection drains being the largest source of C fluxes.

Effects of pine sawdust, hardwood sawdust, and peat on bareroot soil properties

Treesearch

Paul Koll; Martin F. Jurgensen; R. Kasten Dumroese

2010-01-01

We investigated the effects of three organic amendments on soil properties and seedling growth at the USDA Forest Service JW Toumey Nursery in Watersmeet, MI. Pine sawdust (red pine, Pinus resinosa), hardwood sawdust (maple [Acer spp.] and aspen [Populus spp.]), and peat were individually incorporated into a loamy sand nursery soil in August 2006, and soil properties...

Thermal properties of degraded lowland peat-moorsh soils

NASA Astrophysics Data System (ADS)

Gnatowski, Tomasz

2016-04-01

Soil thermal properties, i.e.: specific heat capacity (c), thermal conductivity (K), volumetric heat capacity (C) govern the thermal environment and heat transport through the soil. Hence the precise knowledge and accurate predictions of these properties for peaty soils with high amount of organic matter are especially important for the proper forecasting of soil temperature and thus it may lead to a better assessment of the greenhouse gas emissions created by microbiological activity of the peatlands. The objective of the study was to develop the predictive models of the selected thermal parameters of peat-moorsh soils in terms of their potential applicability for forecasting changes of soil temperature in degraded ecosystems of the Middle Biebrza River Valley area. Evaluation of the soil thermal properties was conducted for the parameters: specific heat capacity (c), volumetric heat capacities of the dry and saturated soil (Cdry, Csat) and thermal conductivities of the dry and saturated soil (Kdry, Ksat). The thermal parameters were measured using the dual-needle probe (KD2-Pro) on soil samples collected from seven peaty soils, representing total 24 horizons. The surface layers were characterized by different degrees of advancement of soil degradation dependent on intensiveness of the cultivation practises (peaty and humic moorsh). The underlying soil layers contain peat deposits of different botanical composition (peat-moss, sedge-reed, reed and alder) and varying degrees of decomposition of the organic matter, from H1 to H7 (von Post scale). Based on the research results it has been shown that the specific heat capacity of the soils differs depending on the type of soil (type of moorsh and type of peat). The range of changes varied from 1276 J.kg-1.K-1 in the humic moorsh soil to 1944 J.kg-1.K-1 in the low decomposed sedge-moss peat. It has also been stated that in degraded peat soils with the increasing of the ash content in the soil the value of specific heat has decreased in a non-linear manner. Thermal parameters of the dry mass of the studied soils (Kdry, Cdry) were characterised by the mean value of approximately 0.11±0.028 W.m-1.K-1 and 0.781±0.220 MJ.m-3.K-1. The application of the correlation analysis showed that the most significant predictor of these properties of soils is the soil bulk density which, respectively explains: 54.6% and 67.1% of their variation. The increase of the accuracy in determining Kdry and Cdry was obtained by developing regression models, which apart from the bulk density also include the chemical properties of the peat soils. In the fully saturated soil the Ksat value ranged from 0.47 to 0.63 W.m-1.K-1, and the Csat varied from 3.200 to 3.995 MJ.m-3.K-1. The variation coefficients of these soil thermal features are at the level of approx. 5%. The obtained results allowed to conclude that the significant diversity of studied soils doesn't cause the significant differences in thermal soil parameters in fully saturated soils. The developed statistical relationships indicate that parameters Ksat and Csat were poorly correlated with saturated moisture content.

Examination of soil contaminated by coal-liquids by size exclusion chromatography in 1-methyl-2-pyrrolidinone solution to evaluate interference from humic and fulvic acids and extracts from peat.

PubMed

Morgan, T J; Herod, A A; Brain, S A; Chambers, F M; Kandiyoti, R

2005-11-18

Soil from a redundant coke oven site has been examined by extraction of soluble materials using 1-methyl-2-pyrrolidinone (NMP) followed by size exclusion chromatography (SEC) of the extracted material. The extracted material was found to closely resemble a high temperature coal tar pitch. Standard humic and fulvic acids were also examined since these materials are very soluble in NMP and would be extracted with pitch if present in the soil. Humic substances derived from peat samples and NMP-extracts of peats were also examined. The results show that the humic and fulvic substances were not extracted directly by NMP from peats. They were extracted using caustic soda solution and were different from the peat extracts in NMP. These results indicate that humic and fulvic acids were soluble in NMP in the protonated polyelectrolyte form but not in the original native polyelectrolyte form. The extraction of soil using NMP followed by SEC appears to be a promising method for identifying contamination by coal-based industries.

Effectiveness of submerged drains in reducing subsidence of peat soils in agricultural use, and their effects on water management and nutrient loading of surface water: modelling of a case study in the western peat soil area of The Netherlands

NASA Astrophysics Data System (ADS)

Hendriks, Rob F. A.; van den Akker, Jan J. A.

2017-04-01

Effectiveness of submerged drains in reducing subsidence of peat soils in agricultural use, and their effects on water management and nutrient loading of surface water: modelling of a case study in the western peat soil area of The Netherlands In the Netherlands, about 8% of the area is covered by peat soils. Most of these soils are in use for dairy farming and, consequently, are drained. Drainage causes decomposition of peat by oxidation and accordingly leads to surface subsidence and greenhouse gas emission. Submerged drains that enhance submerged infiltration of water from ditches during the dry and warm summer half year were, and are still, studied in The Netherlands as a promising tool for reducing peat decomposition by raising groundwater levels. For this purpose, several pilot field studies in the Western part of the Dutch peat area were conducted. Besides the effectiveness of submerged drains in reducing peat decomposition and subsidence by raising groundwater tables, some other relevant or expected effects of these drains were studied. Most important of these are water management and loading of surface water with nutrients nitrogen, phosphorus and sulphate. Because most of these parameters are not easy to assess and all of them are strongly depending on the meteorological conditions during the field studies some of these studies were modelled. The SWAP model was used for evaluating the hydrological results on groundwater table and water discharge and recharge. Effects of submerged drains were assessed by comparing the results of fields with and without drains. An empirical relation between deepest groundwater table and subsidence was used to convert effects on groundwater table to effects on subsidence. With the SWAP-ANIMO model nutrient loading of surface water was modelled on the basis of field results on nutrient concentrations . Calibrated models were used to assess effects in the present situation, as thirty-year averages, under extreme weather conditions and for two extreme climate scenarios of the Royal Netherlands Meteorological Institute. In this study the model results of one of the pilot studies are presented. The case study 'de Krimpenerwaard' is situated in the peat area in the "Green Heart" between the major cities of Amsterdam, The Hague, Rotterdam and Utrecht. Model results show a halving of soil subsidence, a strong increase of water recharge but a lower increase of water discharge, and generally small to moderate effects on nutrient loading , all depending (strongly) on meteorological conditions.

Iron and silicon isotope behaviour accompanying weathering in Icelandic soils, and the implications for iron export from peatlands

NASA Astrophysics Data System (ADS)

Opfergelt, S.; Williams, H. M.; Cornelis, J. T.; Guicharnaud, R. A.; Georg, R. B.; Siebert, C.; Gislason, S. R.; Halliday, A. N.; Burton, K. W.

2017-11-01

Incipient warming of peatlands at high latitudes is expected to modify soil drainage and hence the redox conditions, which has implications for Fe export from soils. This study uses Fe isotopes to assess the processes controlling Fe export in a range of Icelandic soils including peat soils derived from the same parent basalt, where Fe isotope variations principally reflect differences in weathering and drainage. In poorly weathered, well-drained soils (non-peat soils), the limited Fe isotope fractionation in soil solutions relative to the bulk soil (Δ57Fesolution-soil = -0.11 ± 0.12‰) is attributed to proton-promoted mineral dissolution. In the more weathered poorly drained soils (peat soils), the soil solutions are usually lighter than the bulk soil (Δ57Fesolution-soil = -0.41 ± 0.32‰), which indicates that Fe has been mobilised by reductive mineral dissolution and/or ligand-controlled dissolution. The results highlight the presence of Fe-organic complexes in solution in anoxic conditions. An additional constraint on soil weathering is provided by Si isotopes. The Si isotope composition of the soil solutions relative to the soil (Δ30Sisolution-soil = 0.92 ± 0.26‰) generally reflects the incorporation of light Si isotopes in secondary aluminosilicates. Under anoxic conditions in peat soils, the largest Si isotope fractionation in soil solutions relative to the bulk soil is observed (Δ30Sisolution-soil = 1.63 ± 0.40‰) and attributed to the cumulative contribution of secondary clay minerals and amorphous silica precipitation. Si supersaturation in solution with respect to amorphous silica is reached upon freezing when Al availability to form aluminosilicates is limited by the affinity of Al for metal-organic complexes. Therefore, the precipitation of amorphous silica in peat soils indirectly supports the formation of metal-organic complexes in poorly drained soils. These observations highlight that in a scenario of decreasing soil drainage with warming high latitude peatlands, Fe export from soils as Fe-organic complexes will increase, which in turn has implications for Fe transport in rivers, and ultimately the delivery of Fe to the oceans.

Critical evaluation of the use of the hydroxyapatite as a stabilizing agent to reduce the mobility of Zn and Ni in sewage sludge amended soils.

PubMed

Zupancic, Marija; Bukovec, Peter; Milacic, Radmila; Scancar, Janez

2006-01-01

The leachability of zinc (Zn) and nickel (Ni) was investigated in various soil types amended with sewage sludge and sewage sludge treated with hydroxyapatite. Sandy, clay and peat soils were investigated. For leachability tests, plastic columns (diameter 9 cm, height 50 cm) were filled with moist samples up to a height of 25 cm. Sewage sludge (1 kg) was mixed with 4.6 kg of clay and sandy soils and with 6.7 kg of peat soil. For sewage sludge mixtures treated with hydroxyapatite, 0.5 kg of the hydroxyapatite was added to 1 kg of the sewage sludge. Neutral (pH 7) and acid precipitation (pH 3.5) were applied. Acid precipitation was prepared from concentrated HNO(3), H(2)SO(4) and fresh doubly distilled water. The amount of precipitation corresponded to the average annual precipitation for the city of Ljubljana, Slovenia. It was divided into eight equal portions and applied sequentially on the top of the columns. The results indicated that the leachabilities of Zn in sewage sludge amended peat and clay soils were low (below 0.3% of total Zn content) and of Ni in sewage sludge amended sandy, clay and peat soil below 1.9% of total Ni content. In sewage sludge amended sandy soil, the leachability of Zn was higher (11% of Zn content). The pH of precipitation had no influence on the leachability of either metal. Treatment of sewage sludge with hydroxyapatite efficiently reduced the leachability of Zn in sewage sludge amended sandy soil (from 11% to 0.2% of total Zn content). In clay and peat sewage sludge amended soils, soil characteristics rather than hydroxyapatite treatment dominate Zn mobility.

Imaging tropical peatlands in Indonesia using ground-penetrating radar (GPR) and electrical resistivity imaging (ERI): implications for carbon stock estimates and peat soil characterization

Treesearch

X. Comas; N. Terry; M. Warren; R. Kolka; A. Kristiyono; N. Sudiana; D. Nurjaman; T. Darusman

2015-01-01

Current estimates of carbon (C) storage in peatland systems worldwide indicate that tropical peatlands comprise about 15% of the global peat carbon pool. Such estimates are uncertain due to data gaps regarding organic peat soil thickness, volume and C content. We combined a set of indirect geophysical methods (ground-penetrating radar, GPR, and electrical resistivity...

Physical and chemical characteristics of fibrous peat

NASA Astrophysics Data System (ADS)

Sutejo, Yulindasari; Saggaff, Anis; Rahayu, Wiwik; Hanafiah

2017-11-01

Banyuasin is one of the regency in South Sumatera which has an area of 200.000 Ha of peat land. Peat soil are characterized by high compressibility parameters and low initial shear strength. Block sampling method was used to obtain undisturbed sample. The results of this paper describe the characteristics of peat soil from physical and chemical testing. The physical and chemical characteristics of peat include water content (ω), specific gravity (Gs), Acidity (pH), unit weight (γ), and ignition loss tests. SEM and EDS test was done to determine the differences in fiber content and to analyze chemical elements of the specimen. The average results ω, Gs, and pH are 263.538 %, 1.847, and 3.353. Peat is classified in H4 (by Von Post). The results of organic content (OC), ash content (AC), and fiber content (FC) are found 78.693 %, 21.310 %, and 73.703 %. From the results of physical and chemical tests, the peat in Banyuasin is classified as fibrous peat. All the results of the characteristics and classification of fibrous peat compared with published data were close.

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

NASA Astrophysics Data System (ADS)

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

2012-04-01

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

Peat fires as source of polycyclic aromatic hydrocarbons in soils

NASA Astrophysics Data System (ADS)

Tsibart, Anna

2013-04-01

Polycyclic aromatic hydrocarbons (PAHs) arrive from pyrogenic sources including volcanism and the combustion of oil products and plant materials. The production of PAHs during the combustion of plant materials was considered in a number of publications, but their results were mainly obtained in laboratory experiments. Insufficient data are available on the hightemperature production of PAHs in environmental objects. For example, natural fires are frequently related to the PAH sources in landscapes, but very little factual data are available on this topic. On Polistovskii reserve (Russia, Pskov region) the soil series were separated depending on the damage to the plants; these series included soils of plots subjected to fires of different intensities, as well as soils of the background plots. The series of organic and organomineral soils significantly differed in their PAH distributions. In this series, the concentration of PAHs in the upper horizons of the peat soils little varied or slightly decreased, but their accumulation occurred at a depth of 5-10 or 10-20 cm in the soils after the fires. For example, in the series of high moor soils, the content of PAHs in the upper horizons remained almost constant; significant differences were observed in the subsurface horizons: from 2 ng/g in the background soil to 70 ng/g after the fire. In the upper horizons of the oligotrophic peat soils under pine forests, the total PAH content also varied only slightly. At the same time, the content of PAHs in the soil series increased from 15 to 90 ng/g with the increasing pyrogenic damage to the plot. No clear trends of the PAH accumulation were recorded in the organomineral soils. The content of PAHs in the soddy-podzolic soil subjected to fire slightly decreased (from 20 to 10 ng/g) compared to the less damaged soil. In peat fires, the access of oxygen to the fire zone is lower than in forest fires. The oxygen deficit acts as a factor of the organic fragments recombination and PAH production; therefore, larger amounts of PAHs are formed in peat fires. In addition, the peat fires occur directly in the soil layer; therefore, larger amounts of the resulting polyarenes remain in the soils of the fire sites. PAHs also can be formed at the heating of organic matter on the areas adjacent to the fire sites. After the combustion of peat in fires, phenanthrene, chrysene, benz[a]pyrene, and tetraphene accumulate in soils. This is mainly the group of 4-nuclear compounds with the participation of 3-nuclear phenanthrene and 5-nuclear benz[a]pyrene. The formation of high-molecular weight compounds like benz[a]pyrene and, in some places, benzo[ghi]perylene is possible during smoldering under a low oxygen supply.

Age Determination of the Remaining Peat in the Sacramento-San Joaquin Delta, California, USA

USGS Publications Warehouse

Drexler, Judith Z.; de Fontaine, Christian S.; Knifong, Donna L.

2007-01-01

Introduction The Sacramento-San Joaquin Delta of California was once a 1,400 square kilometer (km2) tidal marsh, which contained a vast layer of peat ranging up to 15 meters (m) thick (Atwater and Belknap, 1980). Because of its favorable climate and highly fertile peat soils, the majority of the Delta was drained and reclaimed for agriculture during the late 1800s and early 1900s. Drainage of the peat soils changed the conditions in the surface layers of peat from anaerobic (having no free oxygen present) to aerobic (exposed to the atmosphere). This change in conditions greatly increased the decomposition rate of the peat, which consists largely of organic (plant) matter. Thus began the process of land-surface subsidence, which initially was a result of peat shrinkage and compaction, and later largely was a result of oxidation by which organic carbon in the peat essentially vaporized to carbon dioxide (Deverel and others, 1998; Ingebritsen and Ikehara, 1999). Because of subsidence, the land-surface elevation on farmed islands in the Delta has decreased from a few meters to as much as 8 m below local mean sea level (California Department of Water Resources, 1995; Steve Deverel, Hydrofocus, Inc., written commun., 2007). The USGS, in collaboration with the University of California at Davis, and Hydrofocus Inc. of Davis, California, has been studying the formation of the Delta and the impact of wetland reclamation on the peat column as part of a project called Rates and Evolution of Peat Accretion through Time (REPEAT). The purpose of this report is to provide results on the age of the remaining peat soils on four farmed islands in the Delta.

High Throughput Sequencing to Detect Differences in Methanotrophic Methylococcaceae and Methylocystaceae in Surface Peat, Forest Soil, and Sphagnum Moss in Cranesville Swamp Preserve, West Virginia, USA

PubMed Central

Lau, Evan; Nolan, Edward J.; Dillard, Zachary W.; Dague, Ryan D.; Semple, Amanda L.; Wentzell, Wendi L.

2015-01-01

Northern temperate forest soils and Sphagnum-dominated peatlands are a major source and sink of methane. In these ecosystems, methane is mainly oxidized by aerobic methanotrophic bacteria, which are typically found in aerated forest soils, surface peat, and Sphagnum moss. We contrasted methanotrophic bacterial diversity and abundances from the (i) organic horizon of forest soil; (ii) surface peat; and (iii) submerged Sphagnum moss from Cranesville Swamp Preserve, West Virginia, using multiplex sequencing of bacterial 16S rRNA (V3 region) gene amplicons. From ~1 million reads, >50,000 unique OTUs (Operational Taxonomic Units), 29 and 34 unique sequences were detected in the Methylococcaceae and Methylocystaceae, respectively, and 24 potential methanotrophs in the Beijerinckiaceae were also identified. Methylacidiphilum-like methanotrophs were not detected. Proteobacterial methanotrophic bacteria constitute <2% of microbiota in these environments, with the Methylocystaceae one to two orders of magnitude more abundant than the Methylococcaceae in all environments sampled. The Methylococcaceae are also less diverse in forest soil compared to the other two habitats. Nonmetric multidimensional scaling analyses indicated that the majority of methanotrophs from the Methylococcaceae and Methylocystaceae tend to occur in one habitat only (peat or Sphagnum moss) or co-occurred in both Sphagnum moss and peat. This study provides insights into the structure of methanotrophic communities in relationship to habitat type, and suggests that peat and Sphagnum moss can influence methanotroph community structure and biogeography. PMID:27682082

Heterogeneity of carbon loss and its temperature sensitivity in East-European subarctic tundra soils.

PubMed

Diáková, Kateřina; Čapek, Petr; Kohoutová, Iva; Mpamah, Promise A; Bárta, Jiří; Biasi, Christina; Martikainen, Pertti J; Šantrůčková, Hana

2016-09-01

Arctic peatlands store large stocks of organic carbon which are vulnerable to the climate change but their fate is uncertain. There is increasing evidence that a part of it will be lost as a result of faster microbial mineralization. We studied the vulnerability of 3500-5900 years old bare peat uplifted from permafrost layers by cryogenic processes to the surface of an arctic peat plateau. We aimed to find biotic and abiotic drivers of CLOSS from old peat and compare them with those of adjacent, young vegetated soils of the peat plateau and mineral tundra. The soils were incubated in laboratory at three temperatures (4°C, 12°C and 20°C) and two oxygen levels (aerobic, anaerobic). CLOSS was monitored and soil parameters (organic carbon quality, nutrient availability, microbial activity, biomass and stoichiometry, and extracellular oxidative and hydrolytic enzyme pools) were determined. We found that CLOSS from the old peat was constrained by low microbial biomass representing only 0.22% of organic carbon. CLOSS was only slightly reduced by the absence of oxygen and exponentially increased with temperature, showing the same temperature sensitivity under both aerobic and anaerobic conditions. We conclude that carbon in the old bare peat is stabilized by a combination of physical, chemical and biological controls including soil compaction, organic carbon quality, low microbial biomass and the absence of plants. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Microbial Activity in Peat Soil Treated With Ordinary Portland Cement (OPC) and Coal Ashes

NASA Astrophysics Data System (ADS)

Rahman, J. A.; Mohamed, R. M. S. R.; Al-Gheethi, A. A.

2018-04-01

Peat soil is a cumulative of decayed plant fragment which developed as a result of microbial activity. The microbes degrade the organic matter in the peat soils by the production of hydrolysis enzyme. The least decomposed peat, known as fibric peat has big particles and retain lots of water. This made peat having high moisture content, up to 1500 %. The most decomposed peat known as sapric peat having fines particles and less void ratio. The present study aimed to understand the effects of solidification process on the bacterial growth and cellulase (CMCase) enzyme activity. Two types of mixing were designed for fibric, hemic and sapric peats; (i) Ordinary Portland cement (OPC) at an equal amount of dry peat, with 25 % of fly ash (FA) and total of coarse particle, a combination of bottom ash and fibre of 22 – 34 %, (ii) fibric peat was using water-to-binder ratio (w/b) = 1, 50% OPC, 25 % bottom ash (BA) and 25 % FA. For hemic and sapric peat, w/b=3 with 50 % OPC and 50 % BA were used. All samples were prepared triplicates, and were cured for 7, 14, 28 and 56 days in a closed container at room temperature. The results revealed that the first mix design giving a continuous strength development. However, the second mix design shows a decreased in strength pattern after day 28. The influence of the environment factors such as alkaline pH, reduction of the water content and peat temperature has no significant on the reduction amount of native microbes in the peat. The microbes survived in the solidified peat but the amount of microbes were found reduced for all types of mixing Fibric Mixed 1 (FM1), Hemic Mixed 1(HM1) and Sapric Mixed 1 (SM1) were having good strength increment for about 330 – 1427 % with enzymatic activity recorded even after D56. Nevertheless, with increase in the strength development through curing days, the enzymatic activities were reduced. For the time being, it can be concluded that the microbes have the ability to adapt with new environment. The reactivity of the microbes relates with the strength of solidified peat.

Calibrated Hydrothermal Parameters, Barrow, Alaska, 2013

DOE Data Explorer

Atchley, Adam; Painter, Scott; Harp, Dylan; Coon, Ethan; Wilson, Cathy; Liljedahl, Anna; Romanovsky, Vladimir

2015-01-29

A model-observation-experiment process (ModEx) is used to generate three 1D models of characteristic micro-topographical land-formations, which are capable of simulating present active thaw layer (ALT) from current climate conditions. Each column was used in a coupled calibration to identify moss, peat and mineral soil hydrothermal properties to be used in up-scaled simulations. Observational soil temperature data from a tundra site located near Barrow, AK (Area C) is used to calibrate thermal properties of moss, peat, and sandy loam soil to be used in the multiphysics Advanced Terrestrial Simulator (ATS) models. Simulation results are a list of calibrated hydrothermal parameters for moss, peat, and mineral soil hydrothermal parameters.

Sorption of selected organic compounds from water to a peat soil and its humic-acid and humin fractions: Potential sources of the sorption nonlinearity

USGS Publications Warehouse

Chiou, C.T.; Kile, D.E.; Rutherford, D.W.; Sheng, G.; Boyd, S.A.

2000-01-01

The sorption isotherms of ethylene dibromide (EDB), diuron (DUN), and 3,5-dichlorophenol (DCP) from water on the humic acid and humin fractions of a peat soil and on the humic-acid of a muck soil have been measured. The data were compared with those of the solutes with the whole peat from which the humic-acid (HA) and humin (HM) fractions were derived and on which the sorption of the solutes exhibited varying extents of nonlinear capacities at low relative concentrations (C(e)/S(w)). The HA fraction as prepared by the density-fractionated method is relatively pure and presumably free of high- surface-area carbonaceous material (HSACM) that is considered to be responsible for the observed nonlinear sorption for nonpolar solutes (e.g., EDB) on the peat; conversely, the base-insoluble HM fraction as prepared is presumed to be enriched with HSACM, as manifested by the greatly higher BET- (N2) surface area than that of the whole peat. The sorption of EDB on HA exhibits no visible nonlinear effect, whereas the sorption on HM shows an enhanced nonlinearity over that on the whole peat. The sorption of polar DUN and DCP on HA and HM display nonlinear effects comparable with those on the whole peat; the effects are much more significant than those with nonpolar EDB. These results conform to the hypothesis that adsorption onto a small amount of strongly adsorbing HSACM is largely responsible for the nonlinear sorption of nonpolar solutes on soils and that additional specific interactions with the active groups of soil organic matter are responsible for the generally higher nonlinear sorption of the polar solutes.

Biochar as a Substitute for Peat in Greenhouse Growing Media: Soil Water Characteristics and Carbon Leaching Dynamics

NASA Astrophysics Data System (ADS)

Johnson, M. S.; Hilbert, I.; Jollymore, A. J.

2012-12-01

Biochar (charcoal derived from waste biomass via pyrolysis) has the potential to be used as part of regional scale carbon sequestration strategies. By providing a stable form of carbon that is resistant to decay in soils, biochar can be utilized in a wide range of applications to improve the sustainability of land use management practices. Due to its high water holding capacity, surface area and charge density, it could provide a substitute for peat that is widely used in horticultural activities. Globally, peat production in 2010 amounted to 23.4 Mt, with more than a third of this used for horticulture. In Canada, essentially all peat produced is used for horticulture, with each ton of peat extracted also contributing about 0.7 t CO2e in combined greenhouse gas emissions related to production, transportation and use of peat. We evaluated biochar produced on farm from red alder as a peat substitute in terms of soil water characteristics and carbon leaching in greenhouse growing media (e.g. potting mix). Biochar mixing ratios of 10% (v/v) and greater provided water holding capacity equivalent to peat-based potting mixes. We also present results from a laboratory wetting experiment in which we characterized leachate for dissolved organic carbon (DOC) concentration and DOC characteristics using spectral methods (uV-Vis and fluorescence spectroscopy).

The Characteristics of Peats and Co2 Emission Due to Fire in Industrial Plant Forests

NASA Astrophysics Data System (ADS)

Ratnaningsih, Ambar Tri; Rayahu Prasytaningsih, Sri

2017-12-01

Riau Province has a high threat to forest fire in peat soils, especially in industrial forest areas. The impact of fires will produce carbon (CO2) emissions in the atmosphere. The magnitude of carbon losses from the burning of peatlands can be estimated by knowing the characteristics of the fire peat and estimating CO2 emissions produced. The objectives of the study are to find out the characteristics of fire-burning peat, and to estimate carbon storage and CO2 emissions. The location of the research is in the area of industrial forest plantations located in Bengkalis Regency, Riau Province. The method used to measure peat carbon is the method of lost in ignation. The results showed that the research location has a peat depth of 600-800 cm which is considered very deep. The Peat fiber content ranges from 38 to 75, classified as hemic peat. The average bulk density was 0.253 gram cm-3 (0.087-0,896 gram cm-3). The soil ash content is 2.24% and the stored peat carbon stock with 8 meter peat thickness is 10723,69 ton ha-1. Forest fire was predicted to burn peat to a depth of 100 cm and produced CO2 emissions of 6,355,809 tons ha-1.

Applied K fertilizer use efficiency in pineapples grown on a tropical peat soil under residues removal.

PubMed

Ahmed, Osumanu H; Ahmad, Husni M H; Musa, Hanafi M; Rahim, Anuar A; Rastan, Syed Omar S

2005-01-21

In Malaysia, pineapples are grown on peat soils, but most K fertilizer recommendations do not take into account K loss through leaching. The objective of this study was to determine applied K use efficiency under a conventionally recommended fertilization regime in pineapple cultivation with residues removal. Results showed that K recovery from applied K fertilizer in pineapple cultivation on tropical peat soil was low, estimated at 28%. At a depth of 0-10 cm, there was a sharp decrease of soil total K, exchangeable K, and soil solution K days after planting (DAP) for plots with K fertilizer. This decline continued until the end of the study. Soil total, exchangeable, and solution K at the end of the study were generally lower than prior values before the study. There was no significant accumulation of K at depths of 10-25 and 25-45 cm. However, K concentrations throughout the study period were generally lower or equal to their initial status in the soil indicating leaching of the applied K and partly explained the low K recovery. Potassium losses through leaching in pineapple cultivation on tropical peat soils need to be considered in fertilizer recommendations for efficient recovery of applied K.

Peat

USGS Publications Warehouse

Apodaca, Lori E.

2013-01-01

The article looks at the U.S. peat market as of July 2013. Peat is produced from deposits of plant organic materials in wetlands and includes varieties such as reed-sedge, sphagnum moss, and humus. Use for peat include horticultural soil additives, filtration, and adsorbents. Other topics include effects of environmental protection regulations on peat extraction, competition from products such as coir, composted organic waste, and wood products, and peatland carbon sinks.

Development of new index for forest fire risk using satellite images in Indonesia through the direct spectral measurements of soil

NASA Astrophysics Data System (ADS)

Hashimoto, A.; Akita, M.; Takahashi, Y.; Suzuki, H.; Hasegawa, Y.; Ogino, Y.; Naruse, N.; Takahashi, Y.

2016-12-01

In recent years, the smoke caused by the forest fires in Indonesia has become a serious problem. Most of the land in Indonesia is covered with peat moss, which occurs the expanding of fires due to the burning itself. Thus, the surface soil water, reflecting the amount of precipitation in the area, can become the indication of the risk of fires. This study aims to develop a new index reflecting the risk of forest fires in Indonesia using satellite remote sensing through the direct spectral measurements of peat moss soil.We have prepared the peat moss in 7 steps of soil water content measured at an accuracy of ±15 percent (Field pro, WD-3). We obtained spectra between 400nm and 1050nm (Source: halogen lamp, spectroscope: self-made space time, spectral analysis kit) from the peat moss.The obtained spectra show the difference from the previous spectral measurement for the soil in various water content. There are the features, especially, in the wavelength range of ultraviolet (400-450nm) and infrared (530-800nm) as shown in the figure; the more the soil water increases, the lower the reflectance becomes. We have developed a new index using the New deep blue band (433 453nm and NIR band 845 885nm of Landsat 8. The resulting satellite images calculated by our original index appears to reflect the risk of forest fires rather than well-known indices such as Normalized Difference Water Index and Normalized difference Soil Index.In conclusion, we have created a new index that highly reflects to the degree of soil water of a peat soil in Indonesia.

Analysis of volatile organic compound from Elaeis guineensis inflorescences planted on different soil types in Malaysia

NASA Astrophysics Data System (ADS)

Muhamad Fahmi, M. H.; Ahmad Bukhary, A. K.; Norma, H.; Idris, A. B.

2016-11-01

The main attractant compound for Eleidobius kamerunicus to male spikelet Elaeis guineensis (oil palm) were determined by analyzing volatile organic compound extracted from E. guineenses inflorescences planted on different soil types namely peat soil, clay soil and sandy soil. Anthesizing male oil palm inflorescences were randomly choosen from palm aged between 4-5 years old age. Extraction of the volatiles from the oil palm inflorescences were performed by Accelerated Solvent Extraction method (ASE). The extracted volatile compound were determined by using gas chromatography-mass spectrometry. Out of ten identified compound, estragole was found to be a major compound in sandy soil (37.49%), clay soil (30.71%) and peat soil (27.79%). Other compound such as 9,12-octadecadieonic acid and n-hexadecanoic acid were found as major compound in peat soil (27.18%) and (7.45%); sandy soil (14.15 %) and (9.31%); and clay soil (30.23%) and (4.99%). This study shows that estragole was the predominant volatile compound detected in oil palm inflorescences with highly concentrated in palm planted in sandy soil type.

The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources

NASA Astrophysics Data System (ADS)

Ritson, Jonathan P.; Brazier, Richard E.; Graham, Nigel J. D.; Freeman, Chris; Templeton, Michael R.; Clark, Joanna M.

2017-06-01

Drought conditions are expected to increase in frequency and severity as the climate changes, representing a threat to carbon sequestered in peat soils. Downstream water treatment works are also at risk of regulatory compliance failures and higher treatment costs due to the increase in riverine dissolved organic carbon (DOC) often observed after droughts. More frequent droughts may also shift dominant vegetation in peatlands from Sphagnum moss to more drought-tolerant species. This paper examines the impact of drought on the production and treatability of DOC from four vegetation litters (Calluna vulgaris, Juncus effusus, Molinia caerulea and Sphagnum spp.) and a peat soil. We found that mild droughts caused a 39.6 % increase in DOC production from peat and that peat DOC that had been exposed to oxygen was harder to remove by conventional water treatment processes (coagulation/flocculation). Drought had no effect on the amount of DOC production from vegetation litters; however large variation was observed between typical peatland species (Sphagnum and Calluna) and drought-tolerant grassland species (Juncus and Molinia), with the latter producing more DOC per unit weight. This would therefore suggest the increase in riverine DOC often observed post-drought is due entirely to soil microbial processes and DOC solubility rather than litter layer effects. Long-term shifts in species diversity may, therefore, be the most important impact of drought on litter layer DOC flux, whereas pulses related to drought may be observed in peat soils and are likely to become more common in the future. These results provide evidence in support of catchment management which increases the resilience of peat soils to drought, such as ditch blocking to raise water tables.

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

NASA Astrophysics Data System (ADS)

Vlček, Lukáš; Falátková, Kristýna; Schneider, Philipp

2017-06-01

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

Bearing capacity of helical pile foundation in peat soil from different, diameter and spacing of helical plates

NASA Astrophysics Data System (ADS)

Fatnanta, F.; Satibi, S.; Muhardi

2018-03-01

In an area dominated by thick peat soil layers, driven piles foundation is often used. These piles are generally skin friction piles where the pile tips do not reach hard stratum. Since the bearing capacity of the piles rely on the resistance of their smooth skin, the bearing capacity of the piles are generally low. One way to increase the bearing capacity of the piles is by installing helical plates around the pile tips. Many research has been performed on helical pile foundation. However, literature on the use of helical pile foundation on peat soil is still hardly found. This research focus on the study of axial bearing capacity of helical pile foundation in peat soil, especially in Riau Province. These full-scale tests on helical pile foundation were performed in a rectangular box partially embedded into the ground. The box is filled with peat soil, which was taken from Rimbo Panjang area in the district of Kampar, Riau Province. Several helical piles with different number, diameter and spacing of the helical plates have been tested and analysed. The tests result show that helical pile with three helical plates of uniform diameter has better bearing capacity compared to other helical piles with varying diameter and different number of helical plates. The bearing capacity of helical pile foundation is affected by the spacing between helical plates. It is found that the effective helical plates spacing for helical pile foundation with diameter of 15cm to 35cm is between 20cm to 30cm. This behaviour may be considered to apply to other type of helical pile foundations in peat soil.

Phenol oxidase activity in secondary transformed peat-moorsh soils

NASA Astrophysics Data System (ADS)

Styła, K.; Szajdak, L.

2009-04-01

The chemical composition of peat depends on the geobotanical conditions of its formation and on the depth of sampling. The evolution of hydrogenic peat soils is closely related to the genesis of peat and to the changes in water conditions. Due to a number of factors including oscillation of ground water level, different redox potential, changes of aerobic conditions, different plant communities, and root exudes, and products of the degradation of plant remains, peat-moorsh soils may undergo a process of secondary transformation conditions (Sokolowska et al. 2005; Szajdak et al. 2007). Phenol oxidase is one of the few enzymes able to degrade recalcitrant phenolic materials as lignin (Freeman et al. 2004). Phenol oxidase enzymes catalyze polyphenol oxidation in the presence of oxygen (O2) by removing phenolic hydrogen or hydrogenes to from radicals or quinines. These products undergo nucleophilic addition reactions in the presence or absence of free - NH2 group with the eventual production of humic acid-like polymers. The presence of phenol oxidase in soil environments is important in the formation of humic substances a desirable process because the carbon is stored in a stable form (Matocha et al. 2004). The investigations were carried out on the transect of peatland 4.5 km long, located in the Agroecological Landscape Park host D. Chlapowski in Turew (40 km South-West of Poznań, West Polish Lowland). The sites of investigation were located along Wyskoć ditch. The following material was taken from four chosen sites marked as Zbechy, Bridge, Shelterbelt and Hirudo in two layers: cartel (0-50cm) and cattle (50-100cm). The object of this study was to characterize the biochemical properties by the determination of the phenol oxidize activity in two layers of the four different peat-moors soils used as meadow. The phenol oxidase activity was determined spectrophotometrically by measuring quinone formation at λmax=525 nm with catechol as substrate by method of Perucci et al. (2000). In peat the highest activities of phenol oxidase was observed in the combinations marked as Shelterbelt and whereas the lowest - in Zbechy, Bridge and Hirudo. Activities of this enzyme in peat ranged from 15.35 to 38.33 μmol h-1g d.m soil. Increased activities of phenol oxidase have been recorded on the depth 50-100cm - catotelm (21.74-38.33 μmol h-1g d.m soil) in comparison with the depth 0-50cm - acrotelm (15.35-28.32 μmol h-1g d.m soil). References Freeman, C., Ostle N.J., Fener, N., Kang H. 2004. A regulatory role for phenol oxidase during decomposition in peatlands. Soil Biology and Biochemistry, 36, 1663-1667. Matocha Ch.J., Haszler G.R., Grove J.H. 2004. Nitrogen fertilization suppresses soil phenol oxidase enzyme activity in no-tillage systems. Soil Science, 169/10, 708-714. Perucci P., Casucci C., Dumontet S. 2000. An improved method to evaluate the o-diphenol oxidase activity of soil. Soil Biology and Biochemistry, 32, 1927-1933. Sokolowska Z., Szajdak L., Matyka-Sarzyńska D. 2005. Impact of the degree of secondary transformation on amid-base properties of organic compounds in mucks. Geoderma, 127, 80-90. Szajdak L., Szczepański M., Bogacz A. 2007. Impact of secondary transformation of peat-moorsh soils on the decrease of nitrogen and carbon compounds in ground water. Agronomy Research, 5/2, 189-200.

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

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

Armentano, T. V.

1982-01-01

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

Nitrite fixation by humic substances: Nitrogen-15 nuclear magnetic resonance evidence for potential intermediates in chemodenitrification

USGS Publications Warehouse

Thorn, K.A.; Mikita, M.A.

2000-01-01

Studies have suggested that NO2/-, produced during nitrification and denitrification, can become incorporated into soil organic matter and, in one of the processes associated with chemodenitrification, react with organic matter to form trace N gases, including N2O. To gain an understanding of the nitrosation chemistry on a molecular level, soil and aquatic humic substances were reacted with 15N-labeled NaNO2, and analyzed by liquid phase 15N and 13C nuclear magnetic resonance (NMR). The International Humic Substances Society (IHSS) Pahokee peat and peat humic acid were also reacted with Na15NO2 and analyzed by solid-state 15N NMR. In Suwannee River, Armadale, and Laurentian fulvic acids, phenolic rings and activated methylene groups underwent nitrosation to form nitrosophenols (quinone monoximes) and ketoximes, respectively. The oximes underwent Beckmann rearrangements to 2??amides, and Beckmann fragmentations to nitriles. The nitriles in turn underwent hydrolysis to 1??amides. Peaks tentatively identified as imine, indophenol, or azoxybenzene nitrogens were clearly present in spectra of samples nitrosated at pH 6 but diminished at pH 3. The 15N NMR spectrum of the peat humic acid exhibited peaks corresponding with N-nitroso groups in addition to nitrosophenols, ketoximes, and secondary Beckmann reaction products. Formation of N-nitroso groups was more significant in the whole peat compared with the peat humic acid. Carbon-13 NMR analyses also indicated the occurrence of nitrosative demethoxylation in peat and soil humic acids. Reaction of 15N-NH3 fixated fulvic acid with unlabeled NO2/- resulted in nitrosative deamination of aminohydroquinone N, suggesting a previously unrecognized pathway for production of N2 gas in soils fertilized with NH3.Studies have suggested that NO2-, produced during nitrification and denitrification, can become incorporated into soil organic matter and, in one of the processes associated with chemodenitrification, react with organic matter to form trace N gases, including N2O. To gain an understanding of the nitrosation chemistry on a molecular level, soil and aquatic humic substances were reacted with 15N-labeled NaNO2, and analyzed by liquid phase 15N and 13C nuclear magnetic resonance (NMR). The International Humic Substances Society (IHSS) Pahokee peat and peat humic acid were also reacted with Na15NO2 and analyzed by solid-state 15N NMR. In Suwannee River, Armadale, and Laurentian fulvic acids, phenolic rings and activated methylene groups underwent nitrosation to form nitrosophenols (quinone monoximes) and ketoximes, respectively. The oximes underwent Beckmann rearrangements to 2?? amides, and Beckmann fragmentations to nitriles. The nitriles in turn underwent hydrolysis to 1?? amides. Peaks tentatively identified as imine, indophenol, or azoxybenzene nitrogens were dearly present in spectra of samples nitrosated at pH 6 but diminished at pH 3. The 15N NMR spectrum of the peat humic acid exhibited peaks corresponding with N-nitroso groups in addition to nitrosophenols, ketoximes, and secondary Beckmann reaction products. Formation of N-nitroso groups was more significant in the whole peat compared with the peat humic acid. Carbon-13 NMR analyses also indicated the occurrence of nitrosative demethoxylation in peat and soil humic acids. Reaction of 15N-NH3 fixated fulvic acids with unlabeled NO2- resulted in nitrosative deamination of aminohydroquinone N, suggesting a previously unrecognized pathway for production of N2 gas in soils fertilized with NH3.

Modulation of hexavalent chromium toxicity on Οriganum vulgare in an acidic soil amended with peat, lime, and zeolite.

PubMed

Antoniadis, Vasileios; Zanni, Anna A; Levizou, Efi; Shaheen, Sabry M; Dimirkou, Anthoula; Bolan, Nanthi; Rinklebe, Jörg

2018-03-01

Dynamics of chromate (Cr(VI)) in contaminated soils may be modulated by decreasing its phytoavailability via the addition of organic matter-rich amendments, which might accelerate Cr(VI) reduction to inert chromite (Cr(III)) or high-cation exchange capacity amendments. We studied Cr(VI) phytoavailability of oregano in a Cr(VI)-spiked acidic soil non-treated (S) and treated with peat (SP), lime (SL), and zeolite (SZ). The addition of Cr(VI) increased the concentrations of Cr(VI) and Cr(III) in soils and plants, especially in the lime-amended soil. The plant biomass decreased in the lime-amended soil compared to the un-spiked soil (control) due to decreased plant phosphorus concentrations and high Cr(VI) concentrations in root at that treatment. Oregano in the peat-amended soil exhibited significantly less toxic effects, due to the role of organic matter in reducing toxic Cr(VI) to Cr(III) and boosted plant vigour in this treatment. In the lime-amended soil, the parameters of soil Cr(VI), soil Cr(III), and root Cr(III) increased significantly compared to the non-amended soil, indicating that Cr(VI) reduction to Cr(III) was accelerated at high pH. Added zeolite failed to decreased Cr(VI) level to soil and plant. Oregano achieved a total uptake of Cr(III) and Cr(VI) of 0.275 mg in plant kg -1 soil in a pot in the non-amended soil. We conclude that peat as soil amendment might be considered as a suitable option for decreasing Cr(VI) toxicity in soil and plant, and that oregano as tolerant plant species has a certain potential to be used as a Cr accumulator. Copyright © 2017 Elsevier Ltd. All rights reserved.

Function of peatland located on secondary transformed peat-moorsh soils on the purification processes of groundwater and the impact of pH on the rates of the elution of organic matter

NASA Astrophysics Data System (ADS)

Wojciech Szajdak, Lech; Szczepański, Marek

2010-05-01

The investigation of peatland is used to show the water quality functioning with respect to different forms of nitrogen and carbon. The purification of ground water by the transect of 4.5 km long consisting organic soils (peat-moorsh soils) was estimated. This transect is located in the Agroecological Landscape Park in Turew, 40 km South-West of Poznan, West Polish Lowland. There is this transect along Wyskoć ditch. pH, the contents of total and dissolved organic carbon, total nitrogen, N-NO3-, N-NH4+ was measured. Additionally C/N factors of peats were estimated. The investigation has shown the impact of the peatland located on the secondary transformed peat - moorsh soils on the lowering of total nitrogen, ammonium, and nitrates as well as total and dissolved organic carbon in ground water. Peat-moorsh soils were described and classified according to Polish hydrogenic soil classification and World Reference Base Soil Notation. There are four investigated points along to Wyskoc ditch. Two times a month during entire vegetation season the following material was taken from this four chosen sites: samples of peat, from the depth of 0-20 cm, samples of water from the ditch, samples of ground water from wells established for this investigation. Samples of peat-moorsh soils were collected at the depth 0-20 cm. Soils were sampled two times a month from 10 sites of each site. Samples were air dried and crushed to pass a 1 mm-mesh sieve. These 10 sub-samples were mixed for the reason of preparing a 'mean sample', which used for the determination of pH (in 1M KCl), dissolved organic carbon (DOC), total organic carbon (TOC), total nitrogen (Ntotal), and N-NO3- as well as N-NH4+. In water from Wyskoć ditch pH, Ntotal, N-NO3-, N-NH4+, DTC (dissolved total carbon) and DOC (dissolved organic carbon) was measured. Ground water samples were collected from four wells established for this investigation. The water was filtered by the middle velocity separation and pH, N-total, N-NO3-, N-NH4+, DTC (dissolved total carbon) and DOC (dissolved organic carbon) ware measured. Peatland located on the secondary transformed peat - moorsh soils has revealed the lowering in ground water: nitrates 38.5%, N-organic 10%, N-total 24.5%, ammonium 38.7%, dissolved total carbon 33.1%, dissolved total inorganic carbon 10%, and dissolved organic carbon 57.5%. The elution of soil organic matter from peat-moorsh soils in broad range of pH and ionic strength was investigated. The rates of the reaction were calculated from the kinetics of first order reaction model. All experiments were repeated at different pH 6.0, 6.5, 7.0, 8.0, 8.5 of 0.5 M ammonium acetate buffer solution. The investigations have shown the impact of the properties of secondary transformed peat-moorsh soils on the rates of the dissolution of organic matter. The rates of organic matter elution for all samples of peats were significant different at four used wavelengths λ=272 nm, λ=320 nm, λ=465 nm, and λ=665 nm. It was observed that the rates increased between λ=272 nm and λ=320 nm and decreased from λ=465 nm to λ=665 nm. Although, the lowest values of the pseudo first-order rate constants measured at λ=665 nm for all samples of peats from four places ranged from 1.9524 10-4 s-1 to 2.7361 10-4 s-1. Therefore, the highest values of t0.5 ranged from 42.2 to 59.2 min for all samples from Zbęchy, Shelterbelt, Mostek and Hirudo. This work was supported by a grant No. N N305 3204 36 founded by Polish Ministry of Education.

Microbiological profile of selected mucks

NASA Astrophysics Data System (ADS)

Dąbek-Szreniawska, M.; Wyczółkowski, A. I.

2009-04-01

INTRODUCTION Matyka-Sarzynska and Sokolowska (2000) emphasize that peats and peat soils comprise large areas of Poland. The creation of soil begins when the formation of swamp has ended. Gawlik (2000) states that the degree of influence of the mucky process of organic soils on the differentiations of the conditions of growth and development of plants is mainly connected with the changes of moisture-retentive properties of mucks which constitute the material for these soils, and the loss of their wetting capacities. The above-mentioned changes, which usually occur gradually and show a clear connection with the extent of dehydration and, at times, with its duration, intensify significantly when the soils are under cultivation. The mucky process of peat soils leads to transformations of their physical, chemical and biological properties. The main ingredient of peat soils is organic substance. The substance is maintained inside them by the protective activity of water. The process of land improvement reduces the humidity of the environment, and that Intensifies the pace of the activity of soil microorganisms which cause the decay of organic substance. The decay takes place in the direction of two parallel processes: mineralization and humification. All groups of chemical substances constituting peat undergo mineralization. Special attention should be called to the mineralization of carbon and nitrogen compounds, which constitute a large percentage of theorganic substance of the peat organic mass. Okruszko (1976) has examined scientificbases of the classification of peat soils depending on the intensity of the muck process. The aim of this publication was to conduct a microbiological characteristic of selected mucky material. METHODS AND MATERIALS Soil samples used in the experiments were acquired from the Leczynsko-Wlodawski Lake Region, a large area of which constitutes a part of the Poleski National Park, which is covered to a large extent with high peat bogs. It was a mucky-peat soil with different degrees of muck process, described by Gawlik (2000) as MtI - first step of muck process, and MtII - second step of muck process. The numbers of selected groups of microorganisms were established using the cultivation method. The total number of microorganisms, zymogenic, aerobic and anaerobic microorganisms (Fred, Waksman 1928), oligotrophic microorganisms, the number of fungi (Parkinson 1982), ammonifiers (Parkinson et al 1971), nitrogen reducers and amolytic microorganisms (Pochon and Tardieux 1962), were determined. RESULTS The interpretation of the obtained results should take into consideration not only the characteristics of the studied objects, but also the characteristics of the methods used and of the examined microorganisms. As a result of the experiments that were carried out, significant differences of the numbers of the examined groups of microorganisms, depending on the degree of the muck process, have been observed. The number of the examined groups was significantly higher in the soil at the first step muck process than the second step of muck process. Amylolytic bacteria were an exception. Probably, during the muck process, ammonification, nitrification and nitrogen reduction process take place at the same time, which is indicated by the number of individual groups of examined microorganisms. CONCLUSIONS During the muck process, the number of microorganisms in the soil decreases. It can be presupposed that during the muck process, the basic process realized by microorganisms is the degradation of organic substance, using nitrates as oxidizers. Dąbek-Szreniawska M.: 1992 Results of microbiological analysis related to soil physical properties. Zesz. Probl. Post. Nauk Roln., 398, 1-6. Fred E.B., Waksman S.A.: 1928 Laboratory manual of general microbiology. Mc Graw-Hill Book Company, New York - London pp. 145. Gawlik J.: 2000 Division of differently silted peat formations into classes according to their state of secondary transformations. Acta Agrophysica, 26, 17-24. Maciak F.: 1985 MateriaŁ y do ćwiczeń z rekultywacji teren

Effect of mixing geopolymer and peat on bearing capacity in Ogan Komering Ilir (OKI) by California bearing ratio (CBR) test

NASA Astrophysics Data System (ADS)

Raharja, Danang S.; Hadiwardoyo, Sigit P.; Rahayu, Wiwik; Zain, Nasuhi

2017-06-01

Geopolymer is binder material that consists of solid material and the activator solution. Geopolymer material has successfully replaced cement in the manufacture of concrete with aluminosilicate bonding system. Geopolymer concrete has properties similar to cement concrete with high compressive strength, low shrinkage value, relatively low creep value, as well as acid-resistant. Based on these, the addition of polymers in peat soils is expected to improve the bearing capacity of peat soils. A study on the influence of geopolymer addition in peat soils was done by comparing before and after the peat soil was mixed with geopolymer using CBR (California Bearing Ratio) test in unsoaked and soaked conditions. 10% mixture content of the peat dry was used, weighted with a variety of curing time 4 hours, 5 days, and 10 days. There were two methods of mixing: first, peat was mixed with fly ash geopolymer activators and mixed solution (waterglass, NaOH, water), and second, peat was mixed with fly ash and mixed geopolymer (waterglass, NaOH, water, fly ash). Changes were observed in specific gravity, dry density, acidity (pH), and the microscopic structure with Scanning Electron Microscope (SEM). Curing time did not significantly affect the CBR value. It even shows a tendency to decline with longer curing time. The first type mixture obtained CBR value of: 5.4% for 4 hours curing, 4.6% for 5 days curing and 3.6% for 10 days curing. The second type mixture obtained CBR value of: 6.1% for 4 hours curing, 5.2% for 5 days curing and 5.2% for 10 days curing. Furthermore, the specific gravity value, dry density, pH near neutral and swelling percentage increased. From both variants, the second type mixture shows better results than the first type mixture. The results of SEM (Scanning Electron Microscopy) show the structure of the peat which became denser with the fly ash particles filling the peat microporous. Also, the reaction of fly ash with geopolymer is indicated by the solid agglomerates that are larger than normal fly ash particle size.

The legacy of wetland drainage on the remaining peat in the Sacramento-San Joaquin Delta, California, USA

USGS Publications Warehouse

Drexler, Judith Z.; Christian S. de Fontaine,; Steven J. Deverel,

2009-01-01

Throughout the world, many extensive wetlands, such as the Sacramento-San Joaquin Delta of California (hereafter, the Delta), have been drained for agriculture, resulting in land-surface subsidence of peat soils. The purpose of this project was to study the in situ effects of wetland drainage on the remaining peat in the Delta. Peat cores were retrieved from four drained, farmed islands and four relatively undisturbed, marsh islands. Core samples were analyzed for bulk density and percent organic carbon. Macrofossils in the peat were dated using radiocarbon age determination. The peat from the farmed islands is highly distinct from marsh island peat. Bulk density of peat from the farmed islands is generally greater than that of the marsh islands at a given organic carbon content. On the farmed islands, increased bulk density, which is an indication of compaction, decreases with depth within the unoxidized peat zone, whereas, on the marsh islands, bulk density is generally constant with depth except near the surface. Approximately 55–80% of the original peat layer on the farmed islands has been lost due to landsurface subsidence. For the center regions of the farmed islands, this translates into an estimated loss of between 2900-5700 metric tons of organic carbon/hectare. Most of the intact peat just below the currently farmed soil layer is over 4000 years old. Peat loss will continue as long as the artificial water table on the farmed islands is held below the land surface.

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

PubMed

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

2015-01-01

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

Phosphorus mobilization in rewetted fens: the effect of altered peat properties and implications for their restoration.

PubMed

Zak, Dominik; Wagner, Carola; Payer, Brian; Augustin, Jürgen; Gelbrecht, Jörg

2010-07-01

Rewetting of drained fens is necessary to stop further soil degradation and to reestablish important ecological functions. However, substantial changes of peat characteristics in the upper soil layers, due to drainage and land use, could counteract their recovery as nutrient-poor systems for an unknown period. We assessed the importance of altered peat properties, such as the degree of peat decomposition and the amount of redox-sensitive phosphorus (P) compounds, for P mobilization in different degraded fens. An experimental design involving 63 intact peat cores from fens with varying drainage and land-use histories was developed to quantify the mobilization of P, as well as that of iron (Fe), ammonium, carbon dioxide, and methane, all indicators of organic-matter decomposition and/or P-releasing processes. We found that net P release rates in peat cores with highly decomposed peat (range: 0.1-52.3 mg P x m(-2) x d(-1)) were significantly correlated to the amount of P bound to redox-sensitive compounds and the molar Fe:P as well as Al:P ratios of peat. We conclude that the following general rules apply for P mobilization in rewetted fens: (1) elevated levels of P release rates and P concentrations in pore water up to three orders of magnitude larger than under natural reference conditions can only be expected for rewetted fens whose surface soil layers consist of highly decomposed peat; (2) peat characteristics, such as the amount of P bound to redox-sensitive Fe(III) compounds (positive correlation) and molar ratios of Fe:P or Al:P (negative correlations), explain the high range of P release rates; and (3) a critical P export to adjacent lakes or rivers can only be expected if molar Fe:P ratios of highly decomposed peat are less than 10.

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

NASA Astrophysics Data System (ADS)

Vlcek, Lukas; Schneider, Philipp; Falatkova, Kristyna

2017-04-01

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

Effect of Different Peat Size and Pre-Consolidation Pressure of Reconstituted Peat on Effective Undrained Shear Strength Properties

NASA Astrophysics Data System (ADS)

Azhar, ATS; Norhaliza, W.; Ismail, B.; Ezree, AM; Nizam, ZM

2017-08-01

Shear strength of the soil is one of the most important parameters in engineering design, especially during the pre- or post-construction periods, since it is mainly used to measure and evaluate the foundation or slope stability of soil. Peat normally known as a soil that has a very low value of shear strength, and in order to determine and understand the shear strength of the peat, it is a difficult task in geotechnical engineering due to several factors such as types of fabrics, the origin of the soil, water content, organic matter and the degree of humification. The aim of this study is to determine the effective undrained shear strength properties of reconstituted peat of different sizes. All the reconstituted peat samples were formed with the size that passed the opening sieve of 0.425 mm (

Is it clean or contaminated soil? Using petrogenic versus biogenic GC-FID chromatogram patterns to mathematically resolve false petroleum hydrocarbon detections in clean organic soils: a crude oil-spiked peat microcosm experiment.

PubMed

Kelly-Hooper, Francine; Farwell, Andrea J; Pike, Glenna; Kennedy, Jocelyn; Wang, Zhendi; Grunsky, Eric C; Dixon, D George

2013-10-01

The Canadian Council of Ministers of the Environment (CCME) reference method for the Canada-wide standard (CWS) for petroleum hydrocarbon (PHC) in soil provides chemistry analysis standards and guidelines for the management of contaminated sites. However, these methods can coextract natural biogenic organic compounds (BOCs) from organic soils, causing false exceedences of toxicity guidelines. The present 300-d microcosm experiment used CWS PHC tier 1 soil extraction and gas chromatography-flame ionization detector (GC-FID) analysis to develop a new tier 2 mathematical approach to resolving this problem. Carbon fractions F2 (C10-C16), F3 (C16-C34), and F4 (>C34) as well as subfractions F3a (C16-C22) and F3b (C22-C34) were studied in peat and sand spiked once with Federated crude oil. These carbon ranges were also studied in 14 light to heavy crude oils. The F3 range in the clean peat was dominated by F3b, whereas the crude oils had approximately equal F3a and F3b distributions. The F2 was nondetectable in the clean peat but was a significant component in crude oil. The crude oil–spiked peat had elevated F2 and F3a distributions. The BOC-adjusted PHC F3 calculation estimated the true PHC concentrations in the spiked peat. The F2:F3b ratio of less than 0.10 indicated PHC absence in the clean peat, and the ratio of greater than or equal to 0.10 indicated PHC presence in the spiked peat and sand. Validation studies are required to confirm whether this new tier 2 approach is applicable to real-case scenarios. Potential adoption of this approach could minimize unnecessary ecological disruptions of thousands of peatlands throughout Canada while also saving millions of dollars in management costs. © 2013 SETAC.

What controls the oxidative ratio of UK peats? A multi-site study of elemental CHNO concentrations in peat cores

NASA Astrophysics Data System (ADS)

Clay, Gareth; Worrall, Fred; Masiello, Carrie

2013-04-01

The oxidative ratio (OR) is the amount of CO2 sequestered in the terrestrial biosphere for each mol of O2 produced. The OR governs the effectiveness of a terrestrial biome to mitigate the impact of anthropogenic CO2 emissions and it has been used to calculate the balance of terrestrial and oceanic carbon sinks across the globe. However, few studies have investigated the controls of the variability in OR. What factors affect OR - climate? Soil type? Vegetation type? N deposition? Land use? Land use change? Small shifts in OR could have important implications in the global partitioning of CO2 between the atmosphere, biosphere, and oceans. This study looks at peat soils from a series of sites representing a climatic transect across the UK. Duplicate peat cores were taken, along with samples of above-ground vegetation and litter, from sites in northern Scotland (Forsinard), southern Scotland (Auchencorth), northern England (Moor House; Thorne Moor) through the Welsh borders (Whixhall Moss) and Somerset levels (Westhay Moor) to Dartmoor and Bodmin Moor in the south west of England. Sub-samples of the cores were analysed for their CHNO concentrations using a Costech ECS 4010 Elemental combustion system. Using the method of Masiello et al. (2008), OR values could be calculated from these elemental concentrations. Results show that OR values of UK peats varied between 0.82 and 1.27 with a median value of 1.08 which is within the range of world soils. There were significant differences in OR of the peat between sites with the data falling into two broad groupings - Group 1: Forsinard, Auchencorth, Dartmoor and Bodmin Moor; Group 2: Moor House, Thorne Moor, Westhay Moor, Whixhall Moss. Whilst there were significant changes (p < 0.05) in elemental ratios with increasing peat depth (increasing C:N ratio and decreasing O:C ratio) there was no significant difference overall in OR with depth. This paper will explore some of the possible controlling factors on these ratios. Local vegetation was also sampled along with agricultural soils from the local area of the peat cores to compare the relative differences in different mediums. Significant differences (p < 0.01) between vegetation, agricultural soils and surface peat layers were found where vegetation had OR values of 1.03 ± 0.04 and agricultural soils had OR values of 1.15 ± 0.04. Further discussion of these results from these comparisons is also presented in this study.

Assessing the Impact of Land Management on Organic Matter Composition in Peat Soils

NASA Astrophysics Data System (ADS)

Savage, A.; Holden, J.; Wainwright, J.

2010-05-01

Peatlands are seen as important stores of terrestrial carbon, accounting for up to one-third of global soil carbon stocks. In some cases peatlands are shown to be emitters of carbon, in other cases carbon sinks depending on the site conditions and nature of degradation. However, carbon budget calculations carried out to date have a number of uncertainties associated with them and the composition of the carbon is generally not considered when determining carbon budgets. Carbon cycling in peat is driven by four key factors (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). Land management is also recognised as an additional driver, but the impacts of many types of management are poorly understood. Among the four drivers listed by Laiho (2006) substrate quality is seen as the most significant. To date, little work has been carried out to characterise the quality of organic matter in peat soils; rather crude estimates have been made as to the quantity of carbon that is stored in peatlands, yet without understanding the composition of the peat, limitations are imposed on calculations of rates of carbon loss from peatlands. This work seeks to examine how variations in the chemical composition of organic matter in peat varies with land use. The method published by Wieder and Starr (1998) was followed to determine eight fractions: soluble fats and waxes, hot water soluble, hollocellulose, cellulose, soluble phenolics, acid insoluble carbohydrates, water soluble carbohydrates and lignin. Samples were taken from burnt, grazed, drained, afforested and undisturbed sites at the Moor House UNESCO Biosphere Reserve in Northern England. The method was used to identify if differences were present in the recalcitrance of the peat and linked to gaseous carbon emissions data collected during fortnightly monitoring. R. Laiho (2006) Decomposition in peatlands: Reconciling seemingly contrasting results on the impacts of lowered water levels Soil Biology & Biochemistry, 38, 2011-2024. R.K. Wieder & S.T. Starr (1998) Quantitative determination of organic fractions in highly organic, Sphagnum peat soils Communications in Soil Science and Plant Analysis, 29, 847-857.

Analysis and Characterization of Organic Carbon in Early Holocene Wetland Paleosols using Ramped Pyrolysis 14C and Biomarkers

NASA Astrophysics Data System (ADS)

Vetter, L.; Schreiner, K. M.; Fernandez, A.; Rosenheim, B. E.; Tornqvist, T. E.

2014-12-01

Radiocarbon analyses are a key tool for quantifying the dynamics of carbon cycling and storage in both modern soils and Quaternary paleosols. Frequently, bulk 14C dates of paleosol organic carbon provide ages older than the time of soil burial, and 14C dates of geochemical fractions such as alkali and acid extracts (operationally defined as humic acids) can provide anomalously old ages when compared to coeval plant macrofossil dates. Ramped pyrolysis radiocarbon analysis of sedimentary organic material has been employed as a tool for investigating 14C age spectra in sediments with multiple organic carbon sources. Here we combine ramped pyrolysis 14C analysis and biomarker analysis (lignin-phenols and other cupric oxide products) to provide information on the source and diagenetic state of the paleosol organic carbon. We apply these techniques to immature early Holocene brackish wetland entisols from three sediment cores in southeastern Louisiana, along with overlying basal peats. Surprisingly, we find narrow 14C age spectra across all thermal aliquots from both paleosols and peats. The weighted bulk 14C ages from paleosols and overlying peats are within analytical error, and are comparable to independently analyzed 14C AMS dates from charcoal fragments and other plant macrofossils from each peat bed. Our results suggest high turnover rates of carbon in soils relative to input of exogenous carbon sources. These data raise broader questions about processes within the active soil and during pedogenesis and burial of paleosols that can effectively homogenize radiocarbon content in soils across the thermochemical spectrum. The concurrence of paleosol and peat 14C ages also suggests that, in the absence of peats with identifiable plant macrofossils, ramped pyrolysis 14C analyses of paleosols may be used to provide ages for sea-level indicators.

Determination of low methylmercury concentrations in peat soil samples by isotope dilution GC-ICP-MS using distillation and solvent extraction methods.

PubMed

Pietilä, Heidi; Perämäki, Paavo; Piispanen, Juha; Starr, Mike; Nieminen, Tiina; Kantola, Marjatta; Ukonmaanaho, Liisa

2015-04-01

Most often, only total mercury concentrations in soil samples are determined in environmental studies. However, the determination of extremely toxic methylmercury (MeHg) in addition to the total mercury is critical to understand the biogeochemistry of mercury in the environment. In this study, N2-assisted distillation and acidic KBr/CuSO4 solvent extraction methods were applied to isolate MeHg from wet peat soil samples collected from boreal forest catchments. Determination of MeHg was performed using a purge and trap GC-ICP-MS technique with a species-specific isotope dilution quantification. Distillation is known to be more prone to artificial MeHg formation compared to solvent extraction which may result in the erroneous MeHg results, especially with samples containing high amounts of inorganic mercury. However, methylation of inorganic mercury during the distillation step had no effect on the reliability of the final MeHg results when natural peat soil samples were distilled. MeHg concentrations determined in peat soil samples after distillation were compared to those determined after the solvent extraction method. MeHg concentrations in peat soil samples varied from 0.8 to 18 μg kg(-1) (dry weight) and the results obtained with the two different methods did not differ significantly (p=0.05). The distillation method with an isotope dilution GC-ICP-MS was shown to be a reliable method for the determination of low MeHg concentrations in unpolluted soil samples. Furthermore, the distillation method is solvent-free and less time-consuming and labor-intensive when compared to the solvent extraction method. Copyright © 2014 Elsevier Ltd. All rights reserved.

Use of Computer-Aided Tomography (CT) Imaging for Quantifying Coarse Roots, Rhizomes, Peat, and Particle Densities in Marsh Soils

EPA Science Inventory

Computer-aided Tomography (CT) imaging was utilized to quantify wet mass of coarse roots, rhizomes, and peat in cores collected from organic-rich (Jamaica Bay, NY) and mineral (North Inlet, SC) Spartina alterniflora soils. Calibration rods composed of materials with standard dens...

[Oil degradation by basidiomycetes in soil and peat at low temperatures].

PubMed

Kulikova, N A; Klein, O I; Pivchenko, D V; Landesman, E O; Pozdnyakova, N N; Turkovskaya, O V; Zaichik, B Ts; Ruzhitskii, A O; Koroleva, O V

2016-01-01

A total of 17 basidiomycete strains causing white rot and growing on oil-contaminated substrates have been screened. Three strains with high (Steccherinum murashkinskyi), average (Trametes maxima), and low (Pleurotus ostreatus) capacities for the colonization of oil-contaminated substrates have been selected. The potential for degrading crude oil hydrocarbons has been assessed with the use of fungi grown on nonsterile soil and peat at low temperatures. Candida sp. and Rhodococcus sp. commercial strains have been used as reference organisms with oil-degrading ability. All microorganisms introduced in oil-contaminated soil have proved to be ineffective, whereas the inoculation of peat with basidiomycetes and oil-degrading microorganisms accelerated the destruction of oil hydrocarbons. The greatest degradation potential of oil-aliphatic hydrocarbons has been found in S. murashlinskyi. T. maxima turned out to be the most successful in degrading aromatic hydrocarbons. It has been suggested that aboriginal microflora contributes importantly to the effectiveness of oil-destructing microorganisms. T. maxima and S. murashkinskyi strains are promising for further study as oil-oxidizing agents during bioremediation of oil-contaminated peat soil under conditions of low temperatures.

Peat Depth Assessment Using Airborne Geophysical Data for Carbon Stock Modelling

NASA Astrophysics Data System (ADS)

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

2013-04-01

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

The legacy of wetland drainage on the remaining peat in the Sacramento San Joaquin Delta, California, USA

USGS Publications Warehouse

Drexler, J.Z.; De Fontaine, C. S.; Deverel, S.J.

2009-01-01

Throughout the world, many extensive wetlands, such as the Sacramento-San Joaquin Delta of California (hereafter, the Delta), have been drained for agriculture, resulting in land-surface subsidence of peat soils. The purpose of this project was to study the in situ effects of wetland drainage on the remaining peat in the Delta. Peat cores were retrieved from four drained, farmed islands and four relatively undisturbed, marsh islands. Core samples were analyzed for bulk density and percent organic carbon. Macrofossils in the peat were dated using radiocarbon age determination. The peat from the farmed islands is highly distinct from marsh island peat. Bulk density of peat from the farmed islands is generally greater than that of the marsh islands at a given organic carbon content. On the farmed islands, increased bulk density, which is an indication of compaction, decreases with depth within the unoxidized peat zone, whereas, on the marsh islands, bulk density is generally constant with depth except near the surface. Approximately 5580 of the original peat layer on the farmed islands has been lost due to land-surface subsidence. For the center regions of the farmed islands, this translates into an estimated loss of between 29005700 metric tons of organic carbon/hectare. Most of the intact peat just below the currently farmed soil layer is over 4000 years old. Peat loss will continue as long as the artificial water table on the farmed islands is held below the land surface. ?? 2009 The Society of Wetland Scientists.

Actinobacterial Nitrate Reducers and Proteobacterial Denitrifiers Are Abundant in N2O-Metabolizing Palsa Peat

PubMed Central

Palmer, Katharina

2012-01-01

Palsa peats are characterized by elevated, circular frost heaves (peat soil on top of a permanently frozen ice lens) and are strong to moderate sources or even temporary sinks for the greenhouse gas nitrous oxide (N2O). Palsa peats are predicted to react sensitively to global warming. The acidic palsa peat Skalluvaara (approximate pH 4.4) is located in the discontinuous permafrost zone in northwestern Finnish Lapland. In situ N2O fluxes were spatially variable, ranging from 0.01 to −0.02 μmol of N2O m−2 h−1. Fertilization with nitrate stimulated in situ N2O emissions and N2O production in anoxic microcosms without apparent delay. N2O was subsequently consumed in microcosms. Maximal reaction velocities (vmax) of nitrate-dependent denitrification approximated 3 and 1 nmol of N2O per h per gram (dry weight [gDW]) in soil from 0 to 20 cm and below 20 cm of depth, respectively. vmax values of nitrite-dependent denitrification were 2- to 5-fold higher than the vmax nitrate-dependent denitrification, and vmax of N2O consumption was 1- to 6-fold higher than that of nitrite-dependent denitrification, highlighting a high N2O consumption potential. Up to 12 species-level operational taxonomic units (OTUs) of narG, nirK and nirS, and nosZ were retrieved. Detected OTUs suggested the presence of diverse uncultured soil denitrifiers and dissimilatory nitrate reducers, hitherto undetected species, as well as Actino-, Alpha-, and Betaproteobacteria. Copy numbers of nirS always outnumbered those of nirK by 2 orders of magnitude. Copy numbers of nirS tended to be higher, while copy numbers of narG and nosZ tended to be lower in 0- to 20-cm soil than in soil below 20 cm. The collective data suggest that (i) the source and sink functions of palsa peat soils for N2O are associated with denitrification, (ii) actinobacterial nitrate reducers and nirS-type and nosZ-harboring proteobacterial denitrifiers are important players, and (iii) acidic soils like palsa peats represent reservoirs of diverse acid-tolerant denitrifiers associated with N2O fluxes. PMID:22660709

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

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

Peat soil composition as indicator of plants growth environment

NASA Astrophysics Data System (ADS)

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

2009-04-01

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

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

EPA Science Inventory

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

Important physical properties of peat materials

Treesearch

D.H. Boelter

1968-01-01

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

Post-fire fluxes and sources of carbon in previously burnt tropical swamp peatlands, Brunei

NASA Astrophysics Data System (ADS)

Lupascu, M.; Akhtar, H.; Smith, T. E. L.; Sukmaria binti Hj Sukri, R.

2017-12-01

Tropical peatlands hold about 15-19% of the global organic carbon (C) pool of which 77% in Southeast Asia. Nonetheless Southeast Asian peatlands have been exploited for timber and land for agriculture leading to rapid deforestation, extensive drainage and frequent fires. Direct C-emissions through peat combustion must be quantified to examine the impact of peat fires on global and regional C-budgets, however it is also essential to evaluate oxidative decomposition of peat after fires for a complete understanding of ecosystem-scale fire impact. This kind of investigation is necessary also to understand the effect of peat burning on peat decomposition, because burning effects on the belowground environment are variable, depending on burnt frequency and fire severity. After a fire, ecosystems act as a C-source for months-to-years as ecosystem-respiration (Reco) exceeds photosynthesis. Furthermore during fires, the surface peat with a higher proportion of the more modern rapidly-cycled C burns preferentially. The loss of the surface peat possibly can reduce oxidative soil CO2 emissions, as the deeper, older peat, has more recalcitrant compounds. However, CO2emissions from this old C pool are a net flux to the atmosphere compared to the modern C. Within this context, we are quantifying the magnitudes and patterns of ecosystem-atmosphere fluxes of carbon dioxide (CO2) and methane (CH4) through cavity-ring spectroscopy in different transects of an intact tropical peat swamp forest and in two degraded forest areas affected by two and six fires over the last 40 years in Brunei, on the island of Borneo. We are using natural tracers such as δ13C and 14C to investigate the age and sources (auto- and heterotrophic) of C contributing to Reco and we are continuously monitoring soil temperature and water table level. Preliminary data show a similar magnitude of CO2 efflux between the intact (5.3 µmol CO2 m-2 s-1) and burnt areas (6.4 µmol CO2 m-2 s-1), with higher soil temperature in the latter. Our results will give a deeper insight into the vulnerability of the C pool in tropical peat swamp forest after fire events and aim at improving terrestrial soil C budget.

Logged peat swamp forest supports greater macrofungal biodiversity than large-scale oil palm plantations and smallholdings.

PubMed

Shuhada, Siti Noor; Salim, Sabiha; Nobilly, Frisco; Zubaid, Akbar; Azhar, Badrul

2017-09-01

Intensive land expansion of commercial oil palm agricultural lands results in reducing the size of peat swamp forests, particularly in Southeast Asia. The effect of this land conversion on macrofungal biodiversity is, however, understudied. We quantified macrofungal biodiversity by identifying mushroom sporocarps throughout four different habitats; logged peat swamp forest, large-scale oil palm plantation, monoculture, and polyculture smallholdings. We recorded a total of 757 clusters of macrofungi belonging to 127 morphospecies and found that substrates for growing macrofungi were abundant in peat swamp forest; hence, morphospecies richness and macrofungal clusters were significantly greater in logged peat swamp forest than converted oil palm agriculture lands. Environmental factors that influence macrofungi in logged peat swamp forests such as air temperature, humidity, wind speed, soil pH, and soil moisture were different from those in oil palm plantations and smallholdings. We conclude that peat swamp forests are irreplaceable with respect to macrofungal biodiversity. They host much greater macrofungal biodiversity than any of the oil palm agricultural lands. It is imperative that further expansion of oil palm plantation into remaining peat swamp forests should be prohibited in palm oil producing countries. These results imply that macrofungal distribution reflects changes in microclimate between habitats and reduced macrofungal biodiversity may adversely affect decomposition in human-modified landscapes.

A Database and Synthesis of Northern Peatland Soil Properties and Holocene Carbon and Nitrogen Accumulation

NASA Technical Reports Server (NTRS)

Loisel, Julie; Yu, Zicheng; Beilman, David W.; Camill, Philip; Alm, Jukka; Amesbury, Matthew J.; Anderson, David; Andersson, Sofia; Bochicchio, Christopher; Barber, Keith;

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.

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

NASA Astrophysics Data System (ADS)

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

2017-07-01

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

Nitrogen and phosphorus loading from drained wetlands adjacent to Upper Klamath and Agency lakes, Oregon

USGS Publications Warehouse

Snyder, Daniel T.; Morace, Jennifer L.

1997-01-01

The results of this study could be useful in helping to prioritize which drained wetlands may provide the greatest benefits with regard to reducing nutrient loads to the lake if restoration or land-use modifications are instituted. Recent acquisition and planned restoration of drained wetland areas at the Wood River and Williamson River North properties may produce significant reduction in the quantity of nutrients released by the decomposition of peat soils of these areas. If the water table rises to predrainage levels, the peats soils may become inundated most of the year, resulting in the continued long-term storage of nutrients within the peat soils by reducing aerobic decomposition. The maximum benefit, in terms of decreasing potential nutrient loss due to peat decomposition, could be the reduction of total nitrogen and total phosphorus loss to about one-half that of the 1994–95 annual loss estimated for all the drained wetlands sampled for this study.

The influence of aeration and temperature on the structure of bacterial complexes in high-moor peat soil

NASA Astrophysics Data System (ADS)

Kukharenko, O. S.; Pavlova, N. S.; Dobrovol'Skaya, T. G.; Golovchenko, A. V.; Pochatkova, T. N.; Zenova, G. M.; Zvyagintsev, D. G.

2010-05-01

The number and taxonomic structure of the heterotrophic block of aerobic and facultative anaerobic bacteria were studied in monoliths from a high-moor peat (stored at room temperature and in a refrigerator) and in the peat horizons mixed in laboratory vessels. The monitoring lasted for a year. In the T0 horizon, spirilla predominated at room and low temperatures; in the T1 and T2 horizons, bacilli were the dominants. The continuous mixing of the peat layers increased the oxygen concentration and the peat decomposition; hence, the shares of actinomycetes and bacilli (bacteria of the hydrolytic complex) increased. In the peat studied, the bacilli were in the active state; i.e., vegetative cells predominated, whose amount ranged from 65 to 90%. The representatives of the main species of bacilli (the facultative anaerobic forms prevailed) hydrolyzed starch, pectin, and carboxymethylcellulose. Thus, precisely sporiferous bacteria can actively participate in the decomposition of plant polysaccharides in high-moor peat soils that are characterized by low temperatures and an oxygen deficit. The development of actinomycetes is inhibited by low temperatures; they can develop only under elevated temperature and better aeration.

Detecting Dewatering of Peatland Pastures Using Sentinel-1 Satellite Radar Interferometry.

NASA Astrophysics Data System (ADS)

Heuff, F.; Samiei-Esfahany, S.; van Leijen, F. J.; Hanssen, R. F.

2017-12-01

The Netherlands are famous for their polders and the draining of soils to be used as pastures. Around 30% of the pastures are situated on peat soils, mostly in the western part of the Netherlands. Peat is composed of organic materials that oxidize and emit greenhouse gases when exposed to air. Oxidation of peat soils results in volume reduction and subsequent subsidence. As a result, the groundwater level rises relative to the surface. Consequently, the soil needs to be dewatered to keep it sufficiently dry for farming, resulting in more oxidation, and therefore more subsidence. This process is bound to continue until the peat soils have disappeared completely. The societal cost of land subsidence due to peat soils are estimated to be 5200 million euro for urban areas and 200 million euro for peatland pastures, for a period until 2050. Measuring the subsidence is not straightforward, if not impossible, with conventional geodetic means as soft soils make it impossible to install fixed benchmarks for repeated surveying. Also, due to the very fast temporal decorrelation over pastures, conventional InSAR approaches cannot measure a signal due to loss of coherence. Here we deploy a complete set of available SAR data from Sentinel-1, Radarsat-2 and TerraSAR-X to estimate the spatio-temporally varying subsidence signal due to the dewatering of peatland pastures over the western part of the Netherlands. We compute the InSAR coherence matrix for all possible interferometric combination, and compute an equivalent single-master stack to estimate the subsidence. Using terrain and land-use defined coherence estimation areas we optimize the phase estimation over areas severely affected by temporal decorrelation. This leads to a first estimate of deformation signals correlated with ancient shallow soil structures due to fluviatile structures. We use the methodology to investigate the effect of advanced local drainage schemes to slow down the subsidence phenomena.

Transformation of peat horizon in swampy southern taiga forests under the impact of surface drainage

NASA Astrophysics Data System (ADS)

Vomperskii, S. E.; Vomperskaya, M. I.; Glukhova, T. V.; Valyaeva, N. A.

2017-10-01

The results of stationary studies of swampy southern taiga forests in Yaroslavl oblast are presented. Estimates of changes in the thickness of peat horizon in peat podzolic gley soils (Folic Albeluvisols) of forests subjected to clearcutting and further intensive forest management in the past 30 years are given. The mean annual precipitation in these three decades has been 116 mm higher than that during the preceding three decades, which has led to a progressive swamping of spruce stands on heavy loamy soils within virtually flat (with slopes up to 0.0035) surfaces and an increase in the organic matter storage in the peat soil horizon with the mean annual rate of 22-68 g/m2. On more pronounced slopes (0.0050), no swamping of spruce and pine stands growing on sandy soils has taken place. Surface drainage of swampy forests through the network of shallow ditches has led to an increase in the productivity of forests; in most cases, the pool of organic matter in the peat horizon has been decreasing with the mean annual rate of 32-46 g/m2. This attests to the reversible character of swamping in dependence on climatic fluctuations and forestry measures. Changes in the carbon pool of swampy soils during short (several years) excessively wet or excessively dry periods may be significantly higher than the average values for 30 years in different types of forests. This allows us to consider swampy forests as the source of significant errors in the estimates of the current contribution of biota to the carbon cycle, because their role (as well as the role of other forests) is assessed without taking into account considerable short-term fluctuations in the carbon pool of their soils.

The xanthine oxidase activity in different of secondary transformed peat-moorsh soils

NASA Astrophysics Data System (ADS)

Styła, Katarzyna; Wojciech Szajdak, Lech

2010-05-01

The investigations were carried out on the transect of peatland 4.5 km long, located in the Agroecological Landscape Park host D. Chlapowski in Turew (40 km South-West of Poznań, West Polish Lowland). The sites investigation were located along Wyskoć ditch. The following material was taken from four chosen sites marked as Zbęchy, Bridge, Shelterbelt and Hirudo in two layers: acrotelm (0-50 cm) and catotelm (50-100 cm). The object of this study was to characterize the biochemical properties by the determination of the xanthine oxidase activity in two layers (acrotelm and catotelm) of the four different peat-moorsh soils used as meadow. The xanthine oxidase activity was determined spectrophotometrically by measuring uric acid formation at λmax=290 nm with xanthine as substrate. In peat-moorsh soil the highest activities of xanthine oxidasewas observed in the Shelterbelt and whereas the lowest - in Zbęchy, Bridge and Hirudo. Activities of this enzyme in peat-moorsh soil ranged from 5.96 to 19.51 μmol h-1g d.m soil. Increased activities of xanthine oxidase have been recorded on the depth 50-100 cm - catotelm (from 11.71 to 19.51 μmol h-1g d.m soil) in comparison with the depth 0-50 cm - acrotelm (from 5.96 to 14.64 μmol h-1g d.m soil). This work was supported by a grant No. N N305 3204 36 founded by Polish Ministry of Education.

Estonian soil classification as a tool for recording information on soil cover and its matching with local site types, plant covers and humus forms classifications

NASA Astrophysics Data System (ADS)

Kõlli, Raimo; Tõnutare, Tõnu; Rannik, Kaire; Krebstein, Kadri

2015-04-01

Estonian soil classification (ESC) has been used successfully during more than half of century in soil survey, teaching of soil science, generalization of soil databases, arrangement of soils sustainable management and others. The Estonian normally developed (postlithogenic) mineral soils (form 72.4% from total area) are characterized by mean of genetic-functional schema, where the pedo-ecological position of soils (ie. location among other soils) is given by means of three scalars: (i) 8 stage lithic-genetic scalar (from rendzina to podzols) separates soils each from other by parent material, lithic properties, calcareousness, character of soil processes and others, (ii) 6 stage moisture and aeration conditions scalar (from aridic or well aerated to permanently wet or reductic conditions), and (iii) 2-3 stage soil development scalar, which characterizes the intensity of soil forming processes (accumulation of humus, podzolization). The organic soils pedo-ecological schema, which links with histic postlithogenic soils, is elaborated for characterizing of peatlands superficial mantle (form 23.7% from whole soil cover). The position each peat soil species among others on this organic (peat) soil matrix schema is determined by mean of 3 scalars: (i) peat thickness, (ii) type of paludification or peat forming peculiarities, and (iii) stage of peat decomposition or peat type. On the matrix of abnormally developed (synlithogenic) soils (all together 3.9%) the soil species are positioned (i) by proceeding in actual time geological processes as erosion, fluvial processes (at vicinity of rivers, lakes or sea) or transforming by anthropogenic and technological processes, and (ii) by 7 stage moisture conditions (from aridic to subaqual) of soils. The most important functions of soil cover are: (i) being a suitable environment for plant productivity; (ii) forming adequate conditions for decomposition, transformation and conversion of falling litter (characterized by humus cover type); (iii) being compartment for deposition of humus, individual organic compounds, plant nutrition elements, air and water, and (iv) forming (bio)chemically variegated active space for soil type specific edaphon. For studying of ESC matching with others ecosystem compartments classifications the comparative analysis of corresponding classification schemas was done. It may be concluded that forest and natural grasslands site types as well the plant associations of forests and grasslands correlate (match) well with ESC and therefore these compartments may be adequately expressed on soil cover matrixes. Special interest merits humus cover (in many countries known as humus form), which is by the issue natural body between plant and soil or plant cover and soil cover. The humus cover, which lied on superficial part of soil cover, has been formed by functional interrelationships of plants and soils, reflects very well the local pedo-ecological conditions (both productivity and decomposition cycles) and, therefore, the humus cover types are good indicators for characterizing of local pedo-ecological conditions. The classification of humus covers (humus forms) should be bound with soil classifications. It is important to develop a pedocentric approach in treating of fabric and functioning of natural and agro-ecosystems. Such, based on soil properties, ecosystem approach to management and protection natural resources is highly recommended at least in temperate climatic regions. The sound matching of soil and plant cover is of decisive importance for sustainable functioning of ecosystem and in attaining a good environmental status of the area.

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

NASA Astrophysics Data System (ADS)

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

2016-12-01

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

Effect of soil type and moisture availability on the foraging behavior of the Formosan subterranean termite (Isoptera: Rhinotermitidae).

PubMed

Cornelius, Mary L; Osbrink, Weste L A

2010-06-01

This study examined the influence of soil type and moisture availability on termite foraging behavior. Physical properties of the soil affected both tunneling behavior and shelter tube construction. Termites tunneled through sand faster than top soil and clay. In containers with top soil and clay, termites built shelter tubes on the sides of the containers. In containers with sand, termites built shelter tubes directly into the air and covered the sides of the container with a layer of sand. The interaction of soil type and moisture availability affected termite movement, feeding, and survival. In assays with moist soils, termites were more likely to aggregate in top soil over potting soil and peat moss. However, termites were more likely to move into containers with dry peat moss and potting soil than containers with dry sand and clay. Termites were also significantly more likely to move into containers with dry potting soil than dry top soil. In the assay with dry soils, termite mortality was high even though termites were able to travel freely between moist sand and dry soil, possibly due to desiccation caused by contact with dry soil. Evaporation from potting soil and peat moss resulted in significant mortality, whereas termites were able to retain enough moisture in top soil, sand, and clay to survive for 25 d. The interaction of soil type and moisture availability influences the distribution of foraging termites in microhabitats.

Mass tree mortality leads to mangrove peat collapse at Bay Islands, Honduras after Hurricane Mitch

USGS Publications Warehouse

Cahoon, D.R.; Hensel, P.; Rybczyk, J.; McKee, K.L.; Proffitt, C.E.; Perez, B.C.

2003-01-01

We measured sediment elevation and accretion dynamics in mangrove forests on the islands of Guanaja and Roatan, Honduras, impacted by Hurricane Mitch in 1998 to determine if collapse of underlying peat was occurring as a result of mass tree mortality. Little is known about the balance between production and decomposition of soil organic matter in the maintenance of sediment elevation of mangrove forests with biogenic soils. Sediment elevation change measured with the rod surface elevation table from 18 months to 33 months after the storm differed significantly among low, medium and high wind impact sites. Mangrove forests suffering minimal to partial mortality gained elevation at a rate (5 mm yeara??1) greater than vertical accretion (2 mm yeara??1) measured from artificial soil marker horizons, suggesting that root production contributed to sediment elevation. Basin forests that suffered mass tree mortality experienced peat collapse of about 11 mm yeara??1 as a result of decomposition of dead root material and sediment compaction. Low soil shear strength and lack of root growth accompanied elevation decreases. Model simulations using the Relative Elevation Model indicate that peat collapse in the high impact basin mangrove forest would be 37 mm yeara??1 for the 2 years immediately after the storm, as root material decomposed. In the absence of renewed root growth, the model predicts that peat collapse will continue for at least 8 more years at a rate (7 mm yeara??1) similar to that measured (11 mm yeara??1). Mass tree mortality caused rapid elevation loss. Few trees survived and recovery of the high impact forest will thus depend primarily on seedling recruitment. Because seedling establishment is controlled in large part by sediment elevation in relation to tide height, continued peat collapse could further impair recovery rates.

Enhanced Dissipation of Selected Herbicides in a Simulated Organic Matrix Biobed: A System to Control On-Farm Point-Source Pollution.

PubMed

Chu, Bei; Eivazi, Frieda

2018-03-01

Most farms have a centralized location to fill spray tanks with pesticides and to flush and clean application equipment. These sites, depending on the frequency of use, could be significant sources of surface and groundwater contamination. One approach to minimize this contamination is to install a treatment system, such as a biobed. This study sought to construct a biobed and test the effects of different biomix materials in enhancing the dissipation of herbicides widely used in crop production. The four types of biomix evaluated had mixing ratios by volume of (1) 12.5% straw:62.5% soil:25% peat, (2) 25% straw:50% soil:25% peat, (3) 12.5% straw:62.5% soil:25% compost, and (4) 25% straw:50% soil:25% compost. The dissipation rates of acetochlor, atrazine, pendimethalin, and trifluralin at different incubation times over 90 d were evaluated. The dissipation of atrazine and pendimethalin in the biomixes were faster than in soil. The half-lives for atrazine were 27.8 d in soil and 14.3 to 20.2 d in the biomixes and those of pendimethalin were 25.5 d in soil and 11.9 to 14.8 d in the biomixes. The dissipation rates and half-lives of acetochlor were similar to those in soil; the trifluralin dissipation rates were slower in the biomixes. The phenol oxidase activity was higher in the peat biomixes than in those containing compost. The results showed that biobed materials, especially those with peat, are effective in degrading selected herbicides. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Determination of the water retention of peat soils in the range of the permanent wilting point.

NASA Astrophysics Data System (ADS)

Nünning, Lena; Bechtold, Michel; Dettmann, Ullrich; Piayda, Arndt; Tiemeyer, Bärbel; Durner, Wolfgang

2017-04-01

Global coverage of peatlands decreases due to the use of peat for horticulture and to the drainage of peatlands for agriculture and forestry. While alternatives for peat in horticulture exist, profitable agriculture on peatlands and climate protection are far more difficult to combine. A controlled water management that is optimized to stabilize yields while reducing peat degradation provides a promising path in this direction. For this goal, profound knowledge of hydraulic properties of organic soil is essential, for which, however, literature is scarce. This study aimed to compare different methods to determine the water retention of organic soils in the dry range (pF 3 to 4.5). Three common methods were compared: two pressure based apparatus (ceramic plate vs. membrane, Eijkelkamp) and a dew point potentiameter (WP4C, Decagon Devices), which is based on the equilibrium of soil water potential and air humidity. Two different types of organic soil samples were analyzed: i) samples wet from the field and ii) samples that were rewetted after oven-drying. Additional WP4C measurements were performed at samples from standard evaporation experiments directly after they have been finished. Results were: 1) no systematic differences between pressure apparatus and WP4C measurements, 2) however, high moisture variability of the samples from the pressure apparatus as well as high variability of the WP4C measurements at these samples when they were removed from these devices which indicated that applied pressure did not establish well in all samples, 3) rewetted oven-dried samples resulted in up to three times lower soil moistures even after long equilibrium times, i.e. there was a strong and long-lasting hysteresis effect that was highest for less degraded peat samples, 4) and highly consistent WP4C measurements at samples from the end of the evaporation experiment. Results provide useful information for deriving reliable water retention characteristics for organic soils.

Magnetic susceptibility and dielectric properties of peat in Central Kalimantan, Indonesia

NASA Astrophysics Data System (ADS)

Budi, Pranitha Septiana; Zulaikah, Siti; Hidayat, Arif; Azzahro, Rosyida

2017-07-01

Peatlands dominate almost all regions of Borneo, yet its utilization has not been developed optimally. Any information in this field could be obtained using soil magnetization methods by determining the magnetic succeptibility in terms of magnetic susceptibility value that could describe the source and type of magnetic minerals which could describe the source and type of magnetic minerals. Moreover, the dielectric properties of peat soil were also investigated to determine the level of water content by using the dielectric constant value. Samples was taken at six different locations along Pulang pisau to Berengbengkel. Magnetic susceptibility mass value at these locations ranged between -0.0009 - 0.712 (×10-6 m3/kg). Based on the average magnetic susceptibility value, samples that were taken from T1, T3 and T5 belonged to the type of paramagnetic mineral, while samples which were taken from T2, T4 and T6 belonged to the group of diamagnetic mineral. The low value of magnetic susceptibility of peat was probably derived from the pedogenic process. The average value of peat soil in six locations has a large dielectric constant value that is 28.2 which indicated that there was considerable moisture content due to the hydrophilic nature of peatland which means that the ability of peat in water binding is considerably high.

Estimating Carbon Stocks Along Depressional Wetlands Using Ground Penetrating Radar (GPR) in the Disney Wilderness Preserve (Orlando, Florida)

NASA Astrophysics Data System (ADS)

McClellan, M. D.; Comas, X.; Wright, W. J.; Mount, G. J.

2014-12-01

Peat soils store a large fraction of the global carbon (C) in soil. It is estimated that 95% of carbon in peatlands is stored in the peat soil, while less than 5% occurs in the vegetation. The majority of studies related to C stocks in peatlands have taken place in northern latitudes leaving the tropical and subtropical latitudes clearly understudied. In this study we use a combination of indirect non-invasive geophysical methods (mainly ground penetrating radar, GPR) as well as direct measurements (direct coring) to calculate total C stocks within subtropical depressional wetlands in the Disney Wilderness Preserve (DWP, Orlando, FL). A set of three-dimensional (3D) GPR surveys were used to detect variability of the peat layer thickness and the underlying peat-sand mix layer across several depressional wetlands. Direct samples collected at selected locations were used to confirm depth of each interface and to estimate C content in the laboratory. Layer thickness estimated from GPR and direct C content were used to estimate total peat volume and C content for the entire depressional wetland. Through the use of aerial photos a relationship between surface area along the depressional wetlands and total peat thickness (and thus C content) was established for the depressions surveyed and applied throughout the entire preserve. This work shows the importance of depressional wetlands as critical contributors of the C budget at the DWP.

Dissolved Organic Carbon and Disinfection By-Product Precursor Release from Managed Peat Soils

USGS Publications Warehouse

Fleck, J.A.; Bossio, D.A.; Fujii, R.

2004-01-01

A wetland restoration demonstration project examined the effects of a permanently flooded wetland on subsidence of peat soils. The project, started in 1997, was done on Twitchell Island, in the Sacramento-San Joaquin Delta of California. Conversion of agricultural land to a wetland has changed many of the biogeochemical processes controlling dissolved organic carbon (DOC) release from the peat soils, relative to the previous land use. Dissolved organic C in delta waters is a concern because it reacts with chlorine, added as a disinfectant in municipal drinking waters, to form carcinogenic disinfection byproducts (DBPs), including trihalomethanes (THMs) and haloacetic acids (HAAs). This study explores the effects of peat soil biogeochemistry on DOC and DBP release under agricultural and wetland management. Results indicate that organic matter source, extent of soil organic matter decomposition, and decomposition pathways all are factors in THM formation. The results show that historical management practices dominate the release of DOC and THM precursors. However, within-site differences indicate that recent management decisions can contribute to changes in DOC quality and THM precursor formation. Not all aromatic forms of carbon are highly reactive and certain environmental conditions produce the specific carbon structures that form THMs. Both HAA and THM precursors are elevated in the DOC released under wetland conditions. The findings of this study emphasize the need to further investigate the roles of organic matter sources, microbial decomposition pathways, and decomposition status of soil organic matter in the release of DOC and DBP precursors from delta soils under varying land-use practices.

Dissolved organic carbon and major and trace elements in peat porewater of sporadic, discontinuous, and continuous permafrost zones of western Siberia

NASA Astrophysics Data System (ADS)

Raudina, Tatiana V.; Loiko, Sergey V.; Lim, Artyom G.; Krickov, Ivan V.; Shirokova, Liudmila S.; Istigechev, Georgy I.; Kuzmina, Daria M.; Kulizhsky, Sergey P.; Vorobyev, Sergey N.; Pokrovsky, Oleg S.

2017-07-01

Mobilization of dissolved organic carbon (DOC) and related trace elements (TEs) from the frozen peat to surface waters in the permafrost zone is expected to enhance under ongoing permafrost thaw and active layer thickness (ALT) deepening in high-latitude regions. The interstitial soil solutions are efficient tracers of ongoing bio-geochemical processes in the critical zone and can help to decipher the intensity of carbon and metals migration from the soil to the rivers and further to the ocean. To this end, we collected, across a 640 km latitudinal transect of the sporadic to continuous permafrost zone of western Siberia peatlands, soil porewaters from 30 cm depth using suction cups and we analyzed DOC, dissolved inorganic carbon (DIC), and 40 major elements and TEs in 0.45 µm filtered fraction of 80 soil porewaters. Despite an expected decrease in the intensity of DOC and TE mobilization from the soil and vegetation litter to the interstitial fluids with the increase in the permafrost coverage and a decrease in the annual temperature and ALT, the DOC and many major and trace elements did not exhibit any distinct decrease in concentration along the latitudinal transect from 62.2 to 67.4° N. The DOC demonstrated a maximum of concentration at 66° N, on the border of the discontinuous/continuous permafrost zone, whereas the DOC concentration in peat soil solutions from the continuous permafrost zone was equal to or higher than that in the sporadic/discontinuous permafrost zone. Moreover, a number of major (Ca, Mg) and trace (Al, Ti, Sr, Ga, rare earth elements (REEs), Zr, Hf, Th) elements exhibited an increasing, not decreasing, northward concentration trend. We hypothesize that the effects of temperature and thickness of the ALT are of secondary importance relative to the leaching capacity of peat, which is in turn controlled by the water saturation of the peat core. The water residence time in peat pores also plays a role in enriching the fluids in some elements: the DOC, V, Cu, Pb, REEs, and Th were a factor of 1.5 to 2.0 higher in mounds relative to hollows. As such, it is possible that the time of reaction between the peat and downward infiltrating waters essentially controls the degree of peat porewater enrichments in DOC and other solutes. A 2° northward shift in the position of the permafrost boundaries may bring about a factor of 1.3 ± 0.2 decrease in Ca, Mg, Sr, Al, Fe, Ti, Mn, Ni, Co, V, Zr, Hf, Th, and REE porewater concentration in continuous and discontinuous permafrost zones, and a possible decrease in DOC, specific ultraviolet absorbency (SUVA), Ca, Mg, Fe, and Sr will not exceed 20 % of their current values. The projected increase in ALT and vegetation density, northward migration of the permafrost boundary, or the change of hydrological regime is unlikely to modify chemical composition of peat porewater fluids larger than their natural variations within different micro-landscapes, i.e., within a factor of 2. The decrease in DOC and metal delivery to small rivers and lakes by peat soil leachate may also decrease the overall export of dissolved components from the continuous permafrost zone to the Arctic Ocean. This challenges the current paradigm on the increase in DOC export from the land to the ocean under climate warming in high latitudes.

Frozen peatlands: carbon store and the climate change

NASA Astrophysics Data System (ADS)

Ogneva, Olga; Matyshak, George; Tarkhov, Matvey

2017-04-01

Peatlands soils in the northern permafrost region store approximately 40% of total Earth's soils carbon. These soils develop under the influence of cryogenic processes especially such as freeze-thaw and cryoturbations. Climate change predictions suggest that the frequency of soil freeze-thaw cycles (FTCs) will increase in cool temperate and other high-latitude regions. This trend may cause a response in organic matter decomposition rate - that will result in significant changes of greenhouse gases emission (CO2, CH4). For further predictions improvement of soils response to global climate changes it is necessary to estimate the impact of FTCs in permafrost soils on organic matter decomposition. We investigated the effects of FTCs on microbial biomass, basal respiration, metabolic quotient and dissolved organic matter (DOM) content (carbon - DOC and nitrogen - DON) in frozen peatlands soils by laboratory modelling experiment. Frozen peatlands from the north of Western Siberia in Nadym area (N65°19', E72°53'), in a zone of discontinuous permafrost were studied. The soil cover of these formations is represented by a complex of Typic Histoturbels (Turbic Cryosol) and Typic Historthels (Cryic Histosols). Peat profiles of both soil types were divided into horizons due to decomposition degree (from 15 to 55-60%), age (from 1000 to 5700 yrs) and botanic composition (oligotrophic, mesotrophic, eutrophic). During the experiment, first group of samples of peat horizons (field moisture content) were subjected for 10 times to 3-day FTCs at the temperature of -10 and +4 ° C. In the second group of peat samples were incubated at +4 ° C (with no freeze-thaw). It was established that all studied microbial properties were inversely proportional with decomposition degree of peat, except metabolic quotient. Our results illustrate that microbial activity, estimated by BR, shows resistance to FTCs and doesn't significantly differ after FTCs an average. Microbial biomass (carbon and nitrogen) as well as BR doesn't differ too. The most intensive response to FTCs shows DOM content value which was 1.5 times higher on average in samples after FTCs in comparison with control samples. We suppose that increase of FTCs frequency in soil will result in significant acceleration mineralization of peat. Because these processes exert disruptive effects on soil organic matter, provide converting carbon from pool into forms available for microbial communities, thus involving stored carbon into the carbon turnover.

ALOS2-Indonesia REDD+ Experiment (AIREX): Soil Pool Carbon Application

NASA Astrophysics Data System (ADS)

Raimadoya, M.; Kristijono, A.; Sudiana, N.; Sumawinata, B.; Suwardi; Santoso, E.; Mahargo, D.; Sudarman, S.; Mattikainen, M.

2015-04-01

The bilateral REDD+ agreement between Indonesia and Norway [1] has scheduled that performance based result phase will be started in 2014. Therefore, a transparent and reliable Monitoring, Reporting and V erification (MRV) system for the following carbon pools: (1) biomass, (2) dead organic matter (DOM), and (3) soil, is required to be ready prior to the performance based phase. While the biomass pool could be acquired by space-borne radar (SAR) application i.e. SAR Interferometry (In-SAR) and Polarimetric SAR Interferometry (Pol-InSAR), the method for soil pool is still needed to be developed.A study was implemented in a test site located in the pulp plantation concession of Teluk Meranti Estate, Riau Andalan Pulp and Paper (RAPP), Pelalawan District, Riau Province, Indonesia. The study was intended to evaluate the possibility to estimate soil pool carbon with radar technology. For this purpose, a combination of spaceborne SAR (ALOS/PALSAR) and Ground Penetrating Radar (200 MHz IDS 200 MHz IDS GPR) were used in this exercise.The initial result this study provides a promising outcome for improved soil pool carbon estimation in tropical peat forest condition. The volume estimation of peat soil could be measured from the combination of spaceborne SAR and GPR. Based on this volume, total carbon content can be generated. However, the application of this approach has several limitation such as: (1) GPR survey can only be implemented during the dry season, (2) Rugged Terrain Antenna (RTA) type of GPR should be used for smooth GPR survey in the surface of peat soil which covered by DOM, and (3) the map of peat soil extent by spaceborne SAR need to be improved.

How does conversion from peat swamp forest to oil palm plantation affect emissions of nitrous oxide from the soil? A case study in Jambi, Indonesia

NASA Astrophysics Data System (ADS)

Hartill, Jodie; Hergoualc'h, Kristell; Comeau, Louis-Pierre; Jo, Smith; Lou, Verchot

2017-04-01

Half of the peatlands across Peninsular Malaysia, Borneo and Sumatra are 'managed'. Conversion of peat swamp forest to workable oil palm plantation requires a drastic, potentially irreversible, change to the landscape, to which fertilizers are then routinely applied. A combination of these factors is now widely thought to increase soil nitrous oxide (N2O) emissions, although there is high uncertainty due to gaps in the knowledge, both regionally and nationally. Despite the widespread use of fertilizers in plantations on peats, studies observing their effects remain very limited. Therefore, there is a need for in situ studies to evaluate how environmental parameters (edaphic properties, climate, soil moisture and N availability indicators) influence soil emissions. This 18 month study was located in plots local to each other, representing the start, intermediate and end of the land conversion process; namely mixed peat swamp forest, drained and logged forest and industrial oil palm plantation. Spatial variability was taken into account by differentiating the hollows and hummocks in the mixed peat swamp forest, and the fertilized zone and the zone without fertilizer addition in the oil palm plantation. Gas samples were collected each month from static chambers at the same time as key environmental parameters were measured. Intensive sampling was performed during a 35 day period following two fertilizer applications, in which urea was applied to palms at rates of 0.5 and 1 kg urea palm-1. Soil N2O emissions (kg N ha-1 y-1 ± SE) were low overall, but they were greater in the oil palm plantation (0.8 ± 0.1) than in the mixed peat swamp forest (0.3 ± 0.0) and the drained/logged forest (0.2 ± 0.0). In the mixed peat swamp forest, monthly average fluxes of N2O (g N ha-1 d-1 ± SE) were similar in the hollows (0.6 ± 0.2) and the hummocks (0.3 ± 0.1), whereas in the oil palm plantation they were consistently higher in the zone without fertilizer (2.5 ± 0.4) than in the fertilized zone (0.5 ± 0.1), even after fertilizer application. In the fertilized zones, the N2O fluxes following the two fertilizer applications were 2.4 and 4.5 times higher respectively than fluxes observed in the absence of fertilizers. No change in emissions was observed in the neighboring unfertilized zone at the time of fertilizer application. Soil N2O emissions were related to changes in air and soil temperature in the mixed peat swamp forest, air temperature and water table depth in the drained and logged forest, and rainfall on the day of measurement in the oil palm plantation. This research confirms that peat forest conversion to oil palm plantation has negative consequences on the emissions of N2O. It also corroborates an increase in emission due to fertilizer application, with a magnitude comparable to the emission factor provided by the IPCC guidelines, but this is restricted to the limited area of fertilizer application.

Stability of mercury concentration measurements in archived soil and peat samples

USGS Publications Warehouse

Navrátil, Tomáš; Burns, Douglas; Nováková, Tereza; Kaňa, Jiří; Rohovec, Jan; Roll, Michal; Ettler, Vojtěch

2018-01-01

Archived soil samples can provide important information on the history of environmental contamination and by comparison with recently collected samples, temporal trends can be inferred. Little previous work has addressed whether mercury (Hg) concentrations in soil samples are stable with long-term storage under standard laboratory conditions. In this study, we have re-analyzed using cold vapor atomic adsorption spectroscopy a set of archived soil samples that ranged from relatively pristine mountainous sites to a polluted site near a non-ferrous metal smelter with a wide range of Hg concentrations (6 - 6485 µg kg-1). Samples included organic and mineral soils and peats with a carbon content that ranged from 0.2 to 47.7%. Soil samples were stored in polyethylene bags or bottles and held in laboratory rooms where temperature was not kept to a constant value. Mercury concentrations in four subsets of samples were originally measured in 2000, 2005, 2006 and 2007, and re-analyzed in 2017, i.e. after 17, 12, 11 and 10 years of storage. Statistical analyses of either separated or lumped data yielded no significant differences between the original and current Hg concentrations. Based on these analyses, we show that archived soil and peat samples can be used to evaluate historical soil mercury contamination.

Impact of electromagnetic microwaves on the germination of spores of Streptomyces xanthochromogenes in a peat soil and in a liquid nutrient medium

NASA Astrophysics Data System (ADS)

Komarova, A. S.; Likhacheva, A. A.; Lapygina, E. V.; Maksimova, I. A.; Pozdnyakov, A. I.

2010-01-01

The impact of microwaves on the germination of spores of Streptomyces xanthochromogenes in a liquid nutrient medium and in a peat soil was studied. The treatment of inoculums with microwave radiation affected the development of the microorganisms from the stage of spore germination to the stage of the formation of microcolonies of actinomycetes upon the spore cultivation in the liquid medium. Typical hypnum-herbaceous peat was used to study the rate of germination of the actinomycetal spores in soil. The study of the dynamics of the Streptomyces xanthochromogenes population in the control soil (without treatment with microwaves) showed that the most active development of the culture took place in the soil moistened to 60% of the maximum water capacity. When the soil was moistened to the minimum adsorption capacity, the streptomyces did not complete their full cycle of development. The stimulation of the spore germination and mycelium growth with microwaves in the soil medium required a longer period in comparison with that for the liquid medium. The stimulation of the spore germination was observed in the liquid nutrient medium in the case of 30-s treatment and in the soil in the case of 60-s treatment.

Climate mitigation scenarios of drained peat soils

NASA Astrophysics Data System (ADS)

Kasimir Klemedtsson, Åsa; Coria, Jessica; He, Hongxing; Liu, Xiangping; Nordén, Anna

2014-05-01

The national inventory reports (NIR) submitted to the UNFCCC show Sweden - which as many other countries has wetlands where parts have been drained for agriculture and forestry purposes, - to annually emit 12 million tonnes carbon dioxide equivalents, which is more GHG'es than industrial energy use release in Sweden. Similar conditions can be found in other northern countries, having cool and wet conditions, naturally promoting peat accumulation, and where land use management over the last centuries have promoted draining activities. These drained peatland, though covering only 2% of the land area, have emissions corresponding to 20% of the total reported NIR emissions. This substantial emission contribution, however, is hidden within the Land Use Land Use Change and Forestry sector (LULUCF) where the forest Carbon uptake is even larger, which causes the peat soil emissions become invisible. The only drained soil emission accounted in the Swedish Kyoto reporting is the N2O emission from agricultural drained organic soils of the size 0.5 million tonnes CO2e yr-1. This lack of visibility has made incentives for land use change and management neither implemented nor suggested, however with large potential. Rewetting has the potential to decrease soil mineralization, why CO2 and N2O emissions are mitigated. However if the soil becomes very wet CH4 emission will increase together with hampered plant growth. By ecological modeling, using the CoupModel the climate change mitigation potential have been estimated for four different land use scenarios; 1, Drained peat soil with Spruce (business as usual scenario), 2, raised ground water level to 20 cm depth and Willow plantation, 3, raised ground water level to 10 cm depth and Reed Canary Grass, and 4, rewetting to an average water level in the soil surface with recolonizing wetland plants and mosses. We calculate the volume of biomass production per year, peat decomposition, N2O emission together with nitrate and DOC/POC leakage. Based on the modelling results a cost benefit analysis is performed (economics), guiding to the design of environmental policies needed for land use change to come true.

Effect of past peat cultivation practices on present dynamics of dissolved organic carbon.

PubMed

Frank, S; Tiemeyer, B; Bechtold, M; Lücke, A; Bol, R

2017-01-01

Peatlands are a major source of dissolved organic carbon (DOC) for aquatic ecosystems. Naturally high DOC concentrations in peatlands may be increased further by drainage. For agricultural purposes, peat has frequently been mixed with sand, but the effect of this measure on the release and cycling of DOC has rarely been investigated. This study examined the effects of (i) mixing peat with sand and (ii) water table depth (WTD) on DOC concentrations at three grassland sites on shallow organic soils. The soil solution was sampled bi-weekly for two years with suction plates at 15, 30 and 60cm depth. Selected samples were analysed for dissolved organic nitrogen (DON), δ 13 C DOM and δ 15 N DOM . Average DOC concentrations were surprisingly high, ranging from 161 to 192mgl -1 . There was no significant impact of soil organic carbon (SOC) content or WTD on mean DOC concentrations. At all sites, DOC concentrations were highest at the boundary between the SOC-rich horizon and the mineral subsoil. In contrast to the mean concentrations, the temporal patterns of DOC concentrations, their drivers and the properties of dissolved organic matter (DOM) differed between peat-sand mixtures and peat. DOC concentrations responded to changes in environmental conditions, but only after a lag period of a few weeks. At the sites with a peat-sand mixture, temperature and therefore probably biological activity determined the DOC concentrations. At the peat site, the contribution of vegetation-derived DOM was higher. The highest concentrations occurred during long, cool periods of waterlogging, suggesting a stronger physicochemical-based DOC mobilisation. Overall, these results indicate that mixing peat with sand does not improve water quality and may result in DOC losses of around 200kg DOCha -1 a -1 . Copyright © 2016 Office national des forêts. Published by Elsevier B.V. All rights reserved.

Soil organic matter mineralization of permafrost peat lands and sensitivity to temperature and lack of oxygen

NASA Astrophysics Data System (ADS)

Lamprecht, Richard E.; Diáková, Kateřina; Voigt, Carolina; Šantrůčková, Hana; Martikainen, Pertti; Biasi, Christina

2017-04-01

Globally, a significant pool of soil organic carbon (SOC) (Tarnocai et al. 2009) is stored in arctic peatlands where extensive permafrost prevents the decomposition of old soil organic matter (SOM). Vulnerability of ancient organic depositions in changing environment becomes a considerable issue in future climate models. Palsa mires, a typical cryogenic peatland type in subarctic tundra, are not only an important SOC pool but also have been reported as a source of nitrous oxide (N2O) (Marushchak et al. 2011). Microbial SOM mineralization and its sensitivity to changing environmental conditions are crucial to understand future C losses and greenhouse gas (GHG) fluxes in this abundant landform of subarctic region. The purpose of this experiment was to determine potential SOM mineralization in different layers of deep soil cores from an Arctic peatland. First, we aimed to define a response of C losses and GHG exchange rates to temperature and aerobic/anaerobic conditions in different peat layers down to the permafrost and beyond. Secondly, we sought for relations among SOM mineralization, nutrient availability and parameters of indigenous microbial community. Finally, we attempted to link the potential SOM mineralization of the different peat layers with surface GHG fluxes from a proceeding study conducted with the same, intact soil cores. Five deep peat soil cores were separated into five layers (0 20, 20 40, 40 60 cm, permafrost interface and permafrost layer). Homogenized peat was incubated in a factorial set-up of three temperatures (4, 10, and 16 °C) under aerobic and anaerobic conditions. At the beginning and the end of the total 5.5-months incubation period, we determined C and N availability, microbial biomass and potential activities of extracellular enzymes. Heterotrophic respiration (CO2), methane (CH4) and nitrous oxide (N2O) emissions were monitored weekly at the initial phase and biweekly later during the incubation. First results show that C-loss from aerobic decomposition dominated over C-loss from anaerobic decomposition with clear temperature sensitivities in different peat layers. Moreover, the peat layers showed definite patterns especially to N2O losses, less for CO2 losses. This study addresses the essential question to which extent deeper soil horizons of subarctic organic depositions contribute to the total soil GHG fluxes, and whether the nutrient availability, microbial community and environmental factors (i.e. temperature, O2 availability) constrain the SOM mineralization. REFERENCES Marushchak ME, Pitkämäki A, Koponen H, Biasi C, Seppälä M, Martikainen PJ (2011) Hot spots for nitrous oxide emissions found in different types of permafrost peatlands. Global Change Biol 17:2601-2614 Tarnocai C, Canadell JG, Schuur EAG, Kuhry P, Mazhitova G, Zimov S (2009) Soil organic carbon pools in the northern circumpolar permafrost region. Global Biogeochem Cycles 23

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Soils of the Southwestern Part of the Pacific Coast of Russia

NASA Astrophysics Data System (ADS)

Kostenkov, N. M.; Zharikova, E. A.

2018-02-01

The diversity of soils in the southwestern part of the Pacific coast of Russia (Primorie region) is discussed. Overall, 17 soil types belonging to 8 soil orders have been described in this region, and their morphology and properties have been studied. The diversity of plant communities, geomorphic conditions, and parent materials and relatively mild (as compared with other parts of the Far East region of Russia) specify the great variability of soil cover patterns. Low sea terraces are occupied by various peat, organo-accumulative, and gley soils; poorly drained medium-high terraces are the areas of various dark-humus and darkhumus gleyed soils. Typical and gleyic dark-humus podbels, dark-humus, and dark-humus gleyed soils formed on the high sea terraces. Residual elevations are occupied by brown forest (burozemic) soils, including typical burozems, dark-humus burozems, and gleyic dark-humus burozems and by dark-humus podbels. Various alluvial, gleyic gray-humus, and mucky gley soils are developed on riverine plains. On general, darkhumus soils with the high (>10%) humus content predominate; the area of dark-humus podbels us estimated at about 20%, and the area of dark-humus burozems is about 12%. All the soils in this region are specified by increased acidity values. The exchangeable sodium content is often high in the upper soil horizons with maximum values (0.71-1.19 cmol(c)/kg) in the peat gleyzems, peaty dark-humus soils, mucky-gley soils, and eutrophic peat soils of sea terraces. The grouping of the soils with respect to their physicochemical and agrochemical properties is suggested.

Land use of drained peatlands: Greenhouse gas fluxes, plant production, and economics.

PubMed

Kasimir, Åsa; He, Hongxing; Coria, Jessica; Nordén, Anna

2017-10-10

Drained peatlands are hotspots for greenhouse gas (GHG) emissions, which could be mitigated by rewetting and land use change. We performed an ecological/economic analysis of rewetting drained fertile peatlands in a hemiboreal climate using different land use strategies over 80 years. Vegetation, soil processes, and total GHG emissions were modeled using the CoupModel for four scenarios: (1) business as usual-Norway spruce with average soil water table of -40 cm; (2) willow with groundwater at -20 cm; (3) reed canary grass with groundwater at -10 cm; and (4) a fully rewetted peatland. The predictions were based on previous model calibrations with several high-resolution datasets consisting of water, heat, carbon, and nitrogen cycling. Spruce growth was calibrated by tree-ring data that extended the time period covered. The GHG balance of four scenarios, including vegetation and soil, were 4.7, 7.1, 9.1, and 6.2 Mg CO 2 eq ha -1  year -1 , respectively. The total soil emissions (including litter and peat respiration CO 2 + N 2 O + CH 4 ) were 33.1, 19.3, 15.3, and 11.0 Mg CO 2 eq ha -1  year -1 , respectively, of which the peat loss contributed 35%, 24%, and 7% of the soil emissions for the three drained scenarios, respectively. No peat was lost for the wet peatland. It was also found that draining increases vegetation growth, but not as drastically as peat respiration does. The cost-benefit analysis (CBA) is sensitive to time frame, discount rate, and carbon price. Our results indicate that the net benefit was greater with a somewhat higher soil water table and when the peatland was vegetated with willow and reed canary grass (Scenarios 2 and 3). We conclude that saving peat and avoiding methane release using fairly wet conditions can significantly reduce GHG emissions, and that this strategy should be considered for land use planning and policy-making. © 2017 John Wiley & Sons Ltd.

Dissolved organic carbon concentrations and compositions, and trihalomethane formation potentials in waters from agricultural peat soils, Sacramento-San Joaquin Delta, California; implications for drinking-water quality

USGS Publications Warehouse

Fujii, Roger; Ranalli, Anthony J.; Aiken, George R.; Bergamaschi, Brian A.

1998-01-01

Water exported from the Sacramento-San Joaquin River delta (Delta) is an important drinking-water source for more than 20 million people in California. At times, this water contains elevated concentrations of dissolved organic carbon and bromide, and exceeds the U.S. Environmental Protection Agency's maximum contaminant level for trihalomethanes of 0.100 milligrams per liter if chlorinated for drinking water. About 20 to 50 percent of the trihalomethane precursors to Delta waters originates from drainage water from peat soils on Delta islands. This report elucidates some of the factors and processes controlling and affecting the concentration and quality of dissolved organic carbon released from peat soils and relates the propensity of dissolved organic carbon to form trihalomethanes to its chemical composition.Soil water was sampled from near-surface, oxidized, well-decomposed peat soil (upper soil zone) and deeper, reduced, fibrous peat soil (lower soil zone) from one agricultural field in the west central Delta over 1 year. Concentrations of dissolved organic carbon in the upper soil zone were highly variable, with median concentrations ranging from 46.4 to 83.2 milligrams per liter. Concentrations of dissolved organic carbon in samples from the lower soil zone were much less variable and generally slightly higher than samples from the upper soil zone, with median concentrations ranging from 49.3 to 82.3 milligrams per liter. The dissolved organic carbon from the lower soil zone had significantly higher aromaticity (as measured by specific ultraviolet absorbance) and contained significantly greater amounts of aromatic humic substances (as measured by XAD resin fractionation and carbon-13 nuclear magnetic resonance analysis of XAD isolates) than the dissolved organic carbon from the upper soil zone. These results support the conclusion that more aromatic forms of dissolved organic carbon are produced under anaerobic conditions compared to aerobic conditions. Dissolved organic carbon concentration, trihalomethane formation potential, and ultraviolet absorbance were all highly correlated, showing that trihalomethane precursors increased with increasing dissolved organic carbon and ultraviolet absorbance for whole water samples. Contrary to the generally accepted conceptual model for trihalomethane formation that assumes that aromatic forms of carbon are primary precursors to trihalomethanes, results from this study indicate that dissolved organic carbon aromaticity appears unrelated to trihalomethane formation on a carbon-normalized basis. Thus, dissolved organic carbon aromaticity alone cannot fully explain or predict trihalomethane precursor content, and further investigation of aromatic and nonaromatic forms of carbon will be needed to better identify trihalomethane precursors.

Introducing global peat-specific temperature and pH calibrations based on brGDGT bacterial lipids

NASA Astrophysics Data System (ADS)

Naafs, B. D. A.; Inglis, G. N.; Zheng, Y.; Amesbury, M. J.; Biester, H.; Bindler, R.; Blewett, J.; Burrows, M. A.; del Castillo Torres, D.; Chambers, F. M.; Cohen, A. D.; Evershed, R. P.; Feakins, S. J.; Gałka, M.; Gallego-Sala, A.; Gandois, L.; Gray, D. M.; Hatcher, P. G.; Honorio Coronado, E. N.; Hughes, P. D. M.; Huguet, A.; Könönen, M.; Laggoun-Défarge, F.; Lähteenoja, O.; Lamentowicz, M.; Marchant, R.; McClymont, E.; Pontevedra-Pombal, X.; Ponton, C.; Pourmand, A.; Rizzuti, A. M.; Rochefort, L.; Schellekens, J.; De Vleeschouwer, F.; Pancost, R. D.

2017-07-01

Glycerol dialkyl glycerol tetraethers (GDGTs) are membrane-spanning lipids from Bacteria and Archaea that are ubiquitous in a range of natural archives and especially abundant in peat. Previous work demonstrated that the distribution of bacterial branched GDGTs (brGDGTs) in mineral soils is correlated to environmental factors such as mean annual air temperature (MAAT) and soil pH. However, the influence of these parameters on brGDGT distributions in peat is largely unknown. Here we investigate the distribution of brGDGTs in 470 samples from 96 peatlands around the world with a broad mean annual air temperature (-8 to 27 °C) and pH (3-8) range and present the first peat-specific brGDGT-based temperature and pH calibrations. Our results demonstrate that the degree of cyclisation of brGDGTs in peat is positively correlated with pH, pH = 2.49 × CBTpeat + 8.07 (n = 51, R2 = 0.58, RMSE = 0.8) and the degree of methylation of brGDGTs is positively correlated with MAAT, MAATpeat (°C) = 52.18 × MBT5me‧ - 23.05 (n = 96, R2 = 0.76, RMSE = 4.7 °C). These peat-specific calibrations are distinct from the available mineral soil calibrations. In light of the error in the temperature calibration (∼4.7 °C), we urge caution in any application to reconstruct late Holocene climate variability, where the climatic signals are relatively small, and the duration of excursions could be brief. Instead, these proxies are well-suited to reconstruct large amplitude, longer-term shifts in climate such as deglacial transitions. Indeed, when applied to a peat deposit spanning the late glacial period (∼15.2 kyr), we demonstrate that MAATpeat yields absolute temperatures and relative temperature changes that are consistent with those from other proxies. In addition, the application of MAATpeat to fossil peat (i.e. lignites) has the potential to reconstruct terrestrial climate during the Cenozoic. We conclude that there is clear potential to use brGDGTs in peats and lignites to reconstruct past terrestrial climate.

Study on Magnesium in Rainwater and Fertilizer Infiltration to Solidified Peat

NASA Astrophysics Data System (ADS)

Tajuddin, S. A. M.; Rahman, J. A.; Mohamed, R. M. S. R.

2018-04-01

Magnesium is a component of several primary and secondary minerals in the soil which are essentially insoluble for agricultural purpose. The presence of water infiltrate in the soil allows magnesium to dissolve together into the groundwater. In fertilizers, magnesium is categorized as secondary macronutrient which supplies food and encouraging for plants growth. The main objective of this study was to determine the concentration of magnesium in fibric peat when applied the solidification under different conditions. Physical model was used as a mechanism for the analysis of the experimental data using a soil column as an equipment to produce water leaching. In this investigation, there were four outlets in the soil column which were prepared from the top of the column to the bottom with the purpose of identifying the concentration of magnesium for each soil level. The water leaching of each outlet was tested using atomic absorption spectroscopy (AAS). The results obtained showed that the highest concentrations of magnesium for flush and control condition at outlet 4 was 12.50 ppm and 1.29 ppm respectively. Similarly, fibric with solidified peat under rainwater recorded the highest value of 3.16 at outlet 1 for wet condition while for dry condition at outlet 4 of 1.33 ppm. However, the difference in fibric with solidified peat under rainwater and fertilizer condition showed that the highest value for the wet condition was achieved at outlet 1 with 5.43 ppm while highest value of 1.26 ppm was obtained for the dry condition at the outlet 4. It was concluded that the outlets in the soil column gave a detailed analysis of the concentration of magnesium in the soil which was influenced by the environmental conditions.

A cost-efficient method to assess carbon stocks in tropical peat soil

NASA Astrophysics Data System (ADS)

Warren, M. W.; Kauffman, J. B.; Murdiyarso, D.; Anshari, G.; Hergoualc'h, K.; Kurnianto, S.; Purbopuspito, J.; Gusmayanti, E.; Afifudin, M.; Rahajoe, J.; Alhamd, L.; Limin, S.; Iswandi, A.

2012-11-01

Estimation of belowground carbon stocks in tropical wetland forests requires funding for laboratory analyses and suitable facilities, which are often lacking in developing nations where most tropical wetlands are found. It is therefore beneficial to develop simple analytical tools to assist belowground carbon estimation where financial and technical limitations are common. Here we use published and original data to describe soil carbon density (kgC m-3; Cd) as a function of bulk density (gC cm-3; Bd), which can be used to rapidly estimate belowground carbon storage using Bd measurements only. Predicted carbon densities and stocks are compared with those obtained from direct carbon analysis for ten peat swamp forest stands in three national parks of Indonesia. Analysis of soil carbon density and bulk density from the literature indicated a strong linear relationship (Cd = Bd × 495.14 + 5.41, R2 = 0.93, n = 151) for soils with organic C content > 40%. As organic C content decreases, the relationship between Cd and Bd becomes less predictable as soil texture becomes an important determinant of Cd. The equation predicted belowground C stocks to within 0.92% to 9.57% of observed values. Average bulk density of collected peat samples was 0.127 g cm-3, which is in the upper range of previous reports for Southeast Asian peatlands. When original data were included, the revised equation Cd = Bd × 468.76 + 5.82, with R2 = 0.95 and n = 712, was slightly below the lower 95% confidence interval of the original equation, and tended to decrease Cd estimates. We recommend this last equation for a rapid estimation of soil C stocks for well-developed peat soils where C content > 40%.

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

NASA Astrophysics Data System (ADS)

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

2010-09-01

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

Mapping Soil Carbon in the Yukon Kuskokwim River Delta Alaska

NASA Astrophysics Data System (ADS)

Natali, S.; Fiske, G.; Schade, J. D.; Mann, P. J.; Holmes, R. M.; Ludwig, S.; Melton, S.; Sae-lim, N.; Jardine, L. E.; Navarro-Perez, E.

2017-12-01

Arctic river deltas are hotspots for carbon storage, occupying <1% of the pan-Arctic watershed but containing >10% of carbon stored in arctic permafrost. The Yukon Kuskokwim (YK) Delta, Alaska is located in the lower latitudinal range of the northern permafrost region in an area of relatively warm permafrost that is particularly vulnerable to warming climate. Active layer depths range from 50 cm on peat plateaus to >100 cm in wetland and aquatic ecosystems. The size of the soil organic carbon pool and vulnerability of the carbon in the YK Delta is a major unknown and is critically important as climate warming and increasing fire frequency may make this carbon vulnerable to transport to aquatic and marine systems and the atmosphere. To characterize the size and distribution of soil carbon pools in the YK Delta, we mapped the land cover of a 1910 km2 watershed located in a region of the YK Delta that was impacted by fire in 2015. The map product was the result of an unsupervised classification using the Weka K Means clustering algorithm implemented in Google's Earth Engine. Inputs to the classification were Worldview2 resolution optical imagery (1m), Arctic DEM (5m), and Sentinel 2 level 1C multispectral imagery, including NDVI, (10 m). We collected 100 soil cores (0-30 cm) from sites of different land cover and landscape position, including moist and dry peat plateaus, high and low intensity burned plateaus, fens, and drained lakes; 13 lake sediment cores (0-50 cm); and 20 surface permafrost cores (to 100 cm) from burned and unburned peat plateaus. Active layer and permafrost soils were analyzed for organic matter content, soil moisture content, and carbon and nitrogen pools (30 and 100 cm). Soil carbon content varied across the landscape; average carbon content values for lake sediments were 12% (5- 17% range), fens 26% (9-44%), unburned peat plateaus 41% (34-44%), burned peat plateaus 19% (7-34%). These values will be used to estimate soil carbon pools, which will be applied to the spatial extent of each landcover class in our map, yielding a watershed-wide and spatially explicit map of soil carbon in the YK Delta. This map will provide the basis for understanding where carbon is stored in the watershed and the vulnerability of that carbon to climate change and fire.

Climate changes, lead pollution and soil erosion in south Greenland over the past 700 years

NASA Astrophysics Data System (ADS)

Silva-Sánchez, Noemí; Schofield, J. Edward; Mighall, Tim M.; Martínez Cortizas, Antonio; Edwards, Kevin J.; Foster, Ian

2015-09-01

A peat core from southern Greenland provided a rare opportunity to investigate human-environment interactions, climate change and atmospheric pollution over the last ~ 700 years. X-ray fluorescence, gas chromatography-combustion, isotope ratio mass spectrometry, peat humification and fourier-transform infrared spectroscopy were applied and combined with palynological and archaeological evidence. Variations in peat mineral content seem to be related to soil erosion linked with human activity during the late Norse period (13th-14th centuries AD) and the modern era (20th century). Cooler conditions during the Little Ice Age (LIA) are reflected by both slow rates of peat growth and carbon accumulation, and by low bromine (Br) concentrations. Spörer and Maunder minima in solar activity may be indicated by further declines in Br and enrichment in easily degradable compounds such as polysaccharides. Peat organic matter composition was also influenced by vegetation changes at the end of the LIA when the expansion of oceanic heath was associated with polysaccharide enrichment. Atmospheric lead pollution was recorded in the peat after ~ AD 1845, and peak values occurred in the 1970s. There is indirect support for a predominantly North American lead source, but further Pb isotopic analysis would be needed to confirm this hypothesis.

Impact of managed moorland burning on peat nutrient and base cation status

NASA Astrophysics Data System (ADS)

Palmer, Sheila; Gilpin, Martin; Wearing, Catherine; Johnston, Kerrylyn; Holden, Joseph; Brown, Lee

2013-04-01

Controlled 'patch' burning of moorland vegetation has been used for decades in the UK to stimulate growth of heather (Calluna vulgaris) for game bird habitat and livestock grazing. Typically small patches (300-900 m2) are burned in rotations of 8-25 years. However, our understanding of the short-to-medium term environmental impacts of the practice on these sensitive upland areas has so far been limited by a lack of scientific data. In particular the effect of burning on concentrations of base cations and acid-base status of these highly organic soils has implications both for ecosystem nutrient status and for buffering of acidic waters. As part of the EMBER project peat chemistry data were collected in ten upland blanket peat catchments in the UK. Five catchments were subject to a history of prescribed rotational patch burning. The other five catchments acted as controls which were not subject to burning, nor confounded by other detrimental activities such as drainage or forestry. Soil solution chemistry was also monitored at two intensively studied sites (one regularly burned and one control). Fifty-centimetre soil cores, sectioned into 5-cm intervals, were collected from triplicate patches of four burn ages at each burned site, and from twelve locations at similar hillslope positions at each control site. At the two intensively monitored sites, soil solution chemistry was monitored at four depths in each patch. Across all sites, burned plots had significantly smaller cation exchange capacities, lower concentrations of exchangeable base cations and increased concentrations of exchangeable H+ and Al3+ in near-surface soil. C/N ratios were also lower in burned compared to unburned surface soils. There was no consistent trend between burn age and peat chemistry across all burned sites, possibly reflecting local controls on post-burn recovery rates or external influences on burn management decisions. At the intensively monitored site, plots burned less than two years prior to sampling had significantly smaller exchange capacities and lower concentrations of soil base cations in surface soils relative to plots burned 15-25 years previously. In contrast, surface soil solutions in recently burned plots were enriched in base cations relative to older plots and relative to the control site, possibly due to enhanced leaching at bare soil surfaces. The results offer evidence for an impact of burning on peat nutrient and acid-base status, but suggest that soils recover given time with no further burning.

Do storage dynamics in hydropedological units control hydrological connectivity? (Invited)

NASA Astrophysics Data System (ADS)

Tetzlaff, D.; Birkel, C.; Dick, J.; Geris, J.; Soulsby, C.

2013-12-01

In many northern landscapes, peat-dominated riparian wetlands often characterise the zone of connection between terrestrial drainage and the river network. In order to understand the relationship between connectivity and stream flow generation in a montane headwater catchment, we examined the storage dynamics and isotopic composition of soil water in major hydropedological units. These formed a classic catena sequence for northern catchments from free-draining podzols on steep upper hillslopes through to peaty gleysols in lower receiving slopes to deeper peats (Histosols) in the riparian zone. The peaty gleys and peats remained saturated throughout the year, whilst the podzols showed distinct wetting and drying cycles. In this climatic region, most precipitation events are less than 10mm in magnitude, storm runoff is mainly generated from the Histosols and Gleysols, with runoff coefficients (RCs) typically <10%. In larger events the podzolic soils become strongly connected to the saturated areas and RCs can exceed 40%. Isotopic variations in precipitation are significantly damped in the organic-rich surface horizons of the soils due to mixing with larger volumes of stored water. This damping is accentuated in the deeper soil profile and groundwater. Consequently, the isotopic composition of stream water is also damped, but the strongly reflects that of the near surface waters in the riparian peats. Old 'pre-event' water generally accounts for >80% of flow, even in large events, mainly reflecting the displacement of water stored in the riparian peats and peaty gleys. These riparian areas appear to be the dominant zone where different catchment source waters mix; acting as an 'isostat' that regulates the isotopic composition of stream waters and integrates the Transit Time Distribution (TTD) for the catchment.

Site Simulation of Solidified Peat: Lab Monitoring

NASA Astrophysics Data System (ADS)

Durahim, N. H. Ab; Rahman, J. Abd; Tajuddin, S. F. Mohd; Mohamed, R. M. S. R.; Al-Gheethi, A. A.; Kassim, A. H. Mohd

2018-04-01

In the present research, the solidified peat on site simulation is conducted to obtain soil leaching from soil column study. Few raw materials used in testing such as Ordinary Portland Cement (OPC), Fly ash (FA) and bottom ash (BA) which containing in solidified peat (SP), fertilizer (F), and rainwater (RW) are also admixed in soil column in order to assess their effects. This research was conducted in two conditions which dry and wet condition. Distilled water used to represent rainfall during flushing process while rainwater used to gain leaching during dry and wet condition. The first testing made after leaching process done was Moisture Content (MC). Secondly, Unconfined Compressive Strength (UCS) will be conducted on SP to know the ability of SP strength. These MC and UCS were made before and after SP were applied in soil column. Hence, the both results were compared to see the reliability occur on SP. All leachate samples were tested using Absorption Atomic Spectroscopy (AAS), Ion Chromatography (IC) and Inductively-Coupled Plasma Spectrophotometry (ICP-MS) testing to know the anion and cation present in it.

Surfactant-Modified Soil Amendments Reduce Nitrogen and Phosphorus Leaching in a Sand-Based Rootzone.

PubMed

Shaddox, Travis W; Kruse, Jason K; Miller, Grady L; Nkedi-Kizza, Peter; Sartain, Jerry B

2016-09-01

United States Golf Association putting greens are susceptible to nitrogen (N) and phosphorus (P) leaching. Inorganic soil amendments are used to increase moisture and nutrient retention and may influence N and P leaching. This study was conducted to determine whether N and P leaching could be reduced using soil amendments and surfactant-modified soil amendments. Treatments included a control (sand), sand-peat, zeolite, calcined clay, hexadecyltrimethylammonium-zeolite, and hexadecyltrimethylammonium-calcined clay. Lysimeters were filled with a 30-cm rootzone layer of sand-peat (85:15 by volume), below which a 5-cm treatment layer of amendments was placed. A solution of NO-N, NH-N, and orthophosphate-P (2300, 2480, and 4400 μg mL, respectively) was injected at the top of each lysimeter, and leachate was collected using an autocollector set to collect a 10-mL sample every min until four pore volumes were collected. Uncoated amendments, sand, and peat had no influence on NO-N retention, whereas hexadecyltrimethylammonium-coated amendments reduced NO-N leaching to below detectable limits. Both coated and uncoated amendments reduced NH-N leaching, with zeolite reducing NH-N leached to near zero regardless of hexadecyltrimethylammonium coating. Pure sand resulted in a 13% reduction of applied orthophosphate-P leaching, whereas peat contributed to orthophosphate-P leaching. Surfactant-modified amendments reduced orthophosphate-P leaching by as much as 97%. Surfactant-modified soil amendments can reduce NO-N, NH-N, and orthophosphate-P leaching and, thus, may be a viable option for removing leached N and P before they enter surface or ground waters. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

High Diversity of Planctomycetes in Soils of Two Lichen-Dominated Sub-Arctic Ecosystems of Northwestern Siberia

PubMed Central

Ivanova, Anastasia A.; Kulichevskaya, Irina S.; Merkel, Alexander Y.; Toshchakov, Stepan V.; Dedysh, Svetlana N.

2016-01-01

A wide variety of terrestrial ecosystems in tundra have a ground vegetation cover composed of reindeer lichens (genera Cladonia and Cetraria). The microbial communities of two lichen-dominated ecosystems typical of the sub-arctic zone of northwestern Siberia, that is a forested tundra soil and a shallow acidic peatland, were examined in our study. As revealed by molecular analyses, soil and peat layers just beneath the lichen cover were abundantly colonized by bacteria from the phylum Planctomycetes. Highest abundance of planctomycetes detected by fluorescence in situ hybridization was in the range 2.2–2.7 × 107 cells per gram of wet weight. 16S rRNA gene fragments from the Planctomycetes comprised 8–13% of total 16S rRNA gene reads retrieved using Illumina pair-end sequencing from the soil and peat samples. Lichen-associated assemblages of planctomycetes displayed unexpectedly high diversity, with a total of 89,662 reads representing 1723 operational taxonomic units determined at 97% sequence identity. The soil of forested tundra was dominated by uncultivated members of the family Planctomycetaceae (53–71% of total Planctomycetes-like reads), while sequences affiliated with the Phycisphaera-related group WD2101 (recently assigned to the order Tepidisphaerales) were most abundant in peat (28–51% of total reads). Representatives of the Isosphaera–Singulisphaera group (14–28% of total reads) and the lineages defined by the genera Gemmata (1–4%) and Planctopirus–Rubinisphaera (1–3%) were present in both habitats. Two strains of Singulisphaera-like bacteria were isolated from studied soil and peat samples. These planctomycetes displayed good tolerance of low temperatures (4–15°C) and were capable of growth on a number of polysaccharides, including lichenan, a characteristic component of lichen-derived phytomass. PMID:28066382

Storage dynamics in hydropedological units control hillslope connectivity, runoff generation, and the evolution of catchment transit time distributions

PubMed Central

Tetzlaff, D; Birkel, C; Dick, J; Geris, J; Soulsby, C

2014-01-01

We examined the storage dynamics and isotopic composition of soil water over 12 months in three hydropedological units in order to understand runoff generation in a montane catchment. The units form classic catena sequences from freely draining podzols on steep upper hillslopes through peaty gleys in shallower lower slopes to deeper peats in the riparian zone. The peaty gleys and peats remained saturated throughout the year, while the podzols showed distinct wetting and drying cycles. In this region, most precipitation events are <10 mm in magnitude, and storm runoff is mainly generated from the peats and peaty gleys, with runoff coefficients (RCs) typically <10%. In larger events the podzolic soils become strongly connected to the saturated areas, and RCs can exceed 40%. Isotopic variations in precipitation are significantly damped in the organic-rich soil surface horizons due to mixing with larger volumes of stored water. This damping is accentuated in the deeper soil profile and groundwater. Consequently, the isotopic composition of stream water is also damped, but the dynamics strongly reflect those of the near-surface waters in the riparian peats. “pre-event” water typically accounts for >80% of flow, even in large events, reflecting the displacement of water from the riparian soils that has been stored in the catchment for >2 years. These riparian areas are the key zone where different source waters mix. Our study is novel in showing that they act as “isostats,” not only regulating the isotopic composition of stream water, but also integrating the transit time distribution for the catchment. Key Points Hillslope connectivity is controlled by small storage changes in soil units Different catchment source waters mix in large riparian wetland storage Isotopes show riparian wetlands set the catchment transit time distribution PMID:25506098

Storage dynamics in hydropedological units control hillslope connectivity, runoff generation, and the evolution of catchment transit time distributions.

PubMed

Tetzlaff, D; Birkel, C; Dick, J; Geris, J; Soulsby, C

2014-02-01

We examined the storage dynamics and isotopic composition of soil water over 12 months in three hydropedological units in order to understand runoff generation in a montane catchment. The units form classic catena sequences from freely draining podzols on steep upper hillslopes through peaty gleys in shallower lower slopes to deeper peats in the riparian zone. The peaty gleys and peats remained saturated throughout the year, while the podzols showed distinct wetting and drying cycles. In this region, most precipitation events are <10 mm in magnitude, and storm runoff is mainly generated from the peats and peaty gleys, with runoff coefficients (RCs) typically <10%. In larger events the podzolic soils become strongly connected to the saturated areas, and RCs can exceed 40%. Isotopic variations in precipitation are significantly damped in the organic-rich soil surface horizons due to mixing with larger volumes of stored water. This damping is accentuated in the deeper soil profile and groundwater. Consequently, the isotopic composition of stream water is also damped, but the dynamics strongly reflect those of the near-surface waters in the riparian peats. "pre-event" water typically accounts for >80% of flow, even in large events, reflecting the displacement of water from the riparian soils that has been stored in the catchment for >2 years. These riparian areas are the key zone where different source waters mix. Our study is novel in showing that they act as "isostats," not only regulating the isotopic composition of stream water, but also integrating the transit time distribution for the catchment. Hillslope connectivity is controlled by small storage changes in soil unitsDifferent catchment source waters mix in large riparian wetland storageIsotopes show riparian wetlands set the catchment transit time distribution.

The impact of sheep grazing on the carbon balance of a peatland

NASA Astrophysics Data System (ADS)

Fred, F.; Clay, G. D.

2012-04-01

This study estimates the greenhouse gas (GHG) fluxes resulting from sheep grazing upon upland peat soils. Previous studies have been limited to individual flux pathways or to comparing the presence to the absence of sheep grazing. Therefore, this study combines a model of the physical impact of grazing with models of: biomass production; energy usage in sheep; and peat accumulation. These combined modelling approaches enables this study to consider the indirect and direct impacts of sheep upon the carbon and greenhouse gas balance of a peatland at different grazing intensities as well as the changes between states of grazing. The study considered four vegetation scenarios (Calluna sp., Molinia sp.; reseeded grasses, and Agrostis-Festuca grassland) and a mixed vegetation scenario based upon the vegetation typical of upland peat ecosystems in northern England. Each scenario was considered for altitudes between 350 and 900 m above sea level and for grazing intensities between 0.1 and 2 ewes/ha. The study can show that the total GHG flux at the vegetative carrying capacity tended to decline with increasing altitude for all vegetation scenarios considered except for Molinia sp. The average total GHG flux for all scenarios was 1350 kg CO2eq/ha/yr/ewe/ha, and on average 91% of the fluxes were directly from the sheep and not from the soil ,and are therefore not unique to a peat soil environment. The study suggests that emissions factors for upland sheep have been greatly underestimated. By comparing the total flux due to grazers to the flux to or from the soil allows the study to define a GHG carry capacity. i.e. the grazing intensity at which the flux due to grazing is equal to the sink represented by the peat soils, this GHG carrying capacity varies between 0.2 and 1.7 ewes/ha with this capacity declining with increasing altitude for all model scenarios.

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

PubMed

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

2003-01-01

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

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

PubMed

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

2005-01-01

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

Peat decomposability in managed organic soils in relation to land use, organic matter composition and temperature

NASA Astrophysics Data System (ADS)

Bader, Cédric; Müller, Moritz; Schulin, Rainer; Leifeld, Jens

2018-02-01

Organic soils comprise a large yet fragile carbon (C) store in the global C cycle. Drainage, necessary for agriculture and forestry, triggers rapid decomposition of soil organic matter (SOM), typically increasing in the order forest < grassland < cropland. However, there is also large variation in decomposition due to differences in hydrological conditions, climate and specific management. Here we studied the role of SOM composition on peat decomposability in a variety of differently managed drained organic soils. We collected a total of 560 samples from 21 organic cropland, grassland and forest soils in Switzerland, monitored their CO2 emission rates in lab incubation experiments over 6 months at two temperatures (10 and 20 °C) and related them to various soil characteristics, including bulk density, pH, soil organic carbon (SOC) content and elemental ratios (C / N, H / C and O / C). CO2 release ranged from 6 to 195 mg CO2-C g-1 SOC at 10 °C and from 12 to 423 mg g-1 at 20 °C. This variation occurring under controlled conditions suggests that besides soil water regime, weather and management, SOM composition may be an underestimated factor that determines CO2 fluxes measured in field experiments. However, correlations between the investigated chemical SOM characteristics and CO2 emissions were weak. The latter also did not show a dependence on land-use type, although peat under forest was decomposed the least. High CO2 emissions in some topsoils were probably related to the accrual of labile crop residues. A comparison with published CO2 rates from incubated mineral soils indicated no difference in SOM decomposability between these soil classes, suggesting that accumulation of recent, labile plant materials that presumably account for most of the evolved CO2 is not systematically different between mineral and organic soils. In our data set, temperature sensitivity of decomposition (Q10 on average 2.57 ± 0.05) was the same for all land uses but lowest below 60 cm in croplands and grasslands. This, in turn, indicates a relative accumulation of recalcitrant peat in topsoils.

Ideas and perspectives: why Holocene thermokarst sediments of the Yedoma region do not increase the northern peatland carbon pool

NASA Astrophysics Data System (ADS)

Hugelius, G.; Kuhry, P.; Tarnocai, C.

2015-11-01

Permafrost deposits in the Beringian Yedoma region store large amounts of organic carbon (OC). Walter Anthony et al. (2014) describe a previously unrecognized pool of 159 Pg OC accumulated in Holocene thermokarst sediments deposited in Yedoma region alases (thermokarst depressions). They claim that these alas sediments increase the previously recognized circumpolar permafrost peat OC pool by 50 %. It is stated that previous integrated studies of the permafrost OC pool have failed to account for these deposits because the Northern Circumpolar Soil Carbon Database (NCSCD) is biased towards non-alas field sites and that the soil maps used in the NCSCD underestimate coverage of organic permafrost soils. Here we evaluate these statements against a brief literature review, existing datasets on Yedoma region soil OC storage and independent field-based and geospatial datasets of peat soil distribution in the Siberian Yedoma region. Our findings are summarised in three main points. Firstly, the sediments described by Walter Anthony et al. are primarily mineral lake sediments and do not match widely used international scientific definitions of peat or organic soils. They can therefore not be considered an addition to the circumpolar peat carbon pool. Secondly, independent field data and geospatial analyses show that the Siberian Yedoma regions is dominated by mineral soils, not peatlands. Thus, there is no evidence to suggest any systematic bias in the NCSCD field data or maps. Thirdly, there is spatial overlap between these Holocene thermokarst sediments and previous estimates of permafrost soil and sediment OC stocks. These carbon stocks were already accounted for by previous studies and cannot be added to the permafrost OC count. We suggest that statements made in Walter Anthony et al. (2014) resulted from misunderstandings caused by conflicting definitions and terminologies across different geoscientific disciplines. A careful cross-disciplinary review of terminologies would help future studies to appropriately harmonize definitions between different fields.

Modelling the effect of the physical and chemical characteristics of the materials used as casing layers on the production parameters of Agaricus bisporus.

PubMed

Pardo, Arturo; Emilio Pardo, J; de Juan, J Arturo; Zied, Diego Cunha

2010-12-01

The aim of this research was to show the mathematical data obtained through the correlations found between the physical and chemical characteristics of casing layers and the final mushrooms' properties. For this purpose, 8 casing layers were used: soil, soil + peat moss, soil + black peat, soil + composted pine bark, soil + coconut fibre pith, soil + wood fibre, soil + composted vine shoots and, finally, the casing of La Rioja subjected to the ruffling practice. The conclusion that interplays in the fructification process with only the physical and chemical characteristics of casing are complicated was drawn. The mathematical data obtained in earliness could be explained in non-ruffled cultivation. The variability observed for the mushroom weight and the mushroom diameter variables could be explained in both ruffled and non-ruffled cultivations. Finally, the properties of the final quality of mushrooms were established by regression analysis.

The lignin component of humic substances: Distribution among soil and sedimentary humic, fulvic, and base-insoluble fractions

NASA Astrophysics Data System (ADS)

Ertel, John R.; Hedges, John I.

1984-10-01

Vanillyl, syringyl and cinnamyl phenols occur as CuO oxidation products of humic, fulvic and base-insoluble residual fractions from soils, peat and nearshore marine sediments. However, none of these lignin-derived phenols were released by CuO oxidation of deepsea sediment or its base-extractable organic fractions. Lignin analysis indicated that peat and coastal marine sediments contained significantly higher levels of recognizable vascular plant carbon (20-50%) than soils and offshore marine sediments (0-10%). Although accounting for less than 20% of the total sedimentary (bulk) lignin, lignin components of humic acid fractions compositionally and quantitatively resembled the corresponding bulk samples and baseinsoluble residues. Recognizable lignin, presumably present as intact phenylpropanoid units, accounted for up to 5% of the carbon in peat and coastal humic acids but less than 1% in soil humic acids. Fulvic acid fractions uniformly yielded less lignin-derived phenols in mixtures that were depleted in syringyl and cinnamyl phenols relative to the corresponding humic acid fractions. Within the vanillyl and syringyl families the relative distribution of acidic and aldehydic phenols is a sensitive measure of the degree of oxidative alteration of the lignin component The high acid/aldehyde ratios and the low phenol yields of soils and their humic fractions compared to peat and coastal sediments indicate extensive degradation of the lignin source material. Likewise, the progressively higher acid/aldehyde ratios and lower phenol yields along the sequence: plant tissues (plant debris)-humic acids-fulvic acids suggest that this pattern represents the diagenetic sequence for the aerobic degradation of lignin biopolymers.

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

NASA Astrophysics Data System (ADS)

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

2013-04-01

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

Subsurface structures and properties of a medium-scale peatland area by means of hydrogeophysical methods

NASA Astrophysics Data System (ADS)

Altdorff, Daniel; van der Kruk, Jan; Bechtold, Michel; Tiemeyer, Bärbel; Huismann, Sander

2013-04-01

Intact peatlands are natural sinks of climate-relevant atmospheric CO2 and they are able to store high amounts of organic carbon (C). In addition, intact peatlands are increasingly important given positive effects on biodiversity, hydrological processes and corresponding management issues. Nevertheless, large parts of peatlands in populated areas were modified by human activity during the last centuries. In Germany, more than 90% of the peatlands are drained, mainly for agricultural use. Due to the recent recognition of the positive effects of intact peatlands, there are presently several initiatives for re-wetting parts of these peatlands. However, a restoration to nearly natural conditions needs an evaluation of the current situation as well as an assessment of the restoration potential. Therefore, soil properties like peat layer thickness, bulk density and moisture content need to be known. Non-invasive hydrogeophysical methods offer the possibility for a time and cost-effective characterization of peatlands. In this study, we investigated a medium-scale peatland area (approximately 35 ha) of the 3000 ha large 'Großes Moor' peatland. We present apparent conductivity (ECa) values obtained from Electromagnetic Induction (EMI) measurements representative for three investigation depths (approximately 0.25, 0.5, and 1m). We selected zones with dissimilar ECa to identify areas where strong changes in the subsoil properties with depth are expected (i.e. shallow peat soil on top of sand). Within these areas, additional measurements were made using Ground Penetration Radar (GPR) and soil sampling was performed. In total, six 30 m long GPR profiles and corresponding common midpoint (CMP) measurements were recorded. Additionally, 15 soil cores were taken down to a depth of 0.9 m in order to obtain peat thickness, water content, pore water EC, bulk density (BD), as well as C and N content. Each core was divided into several 5 to 20 cm thick layers to obtain information on the vertical variation of these soil properties with depth. Our results indicate that the peat layer is generally characterized by lower BD, higher pore water EC, higher C content, and higher water contents compared to the underlying sand layer. Preliminary EMI results indicate a ECa - C content correlation that decreases with EMI investigation depth from 0.25 to 1 m. Regarding all soil core properties, the strongest contrast occurs at the peat-sand interface. This contrast also clearly appears in some of the GPR results. The EMI apparent conductivities are positively correlated with soil water content and peat thickness obtained from the soil cores. Preliminary GPR results confirm an increased thickness of the upper layer in areas with increased ECa values. The EMI results also reveal clear patterns linked over several fields with different land use history that represent natural structures in the subsurface.

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

PubMed

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

2018-03-20

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

Hydrogeological and geophysical investigations to evaluate groundwater influences on GHG emissions at the national research site Skogaryd

NASA Astrophysics Data System (ADS)

Banzhaf, Stefan; Klemedtsson, Leif; Sturkell, Erik; Nyström, Elin; Barthel, Roland

2015-04-01

The overall objective of the presented study is to explore the impact of groundwater fluctuations on greenhouse gas (GHG) emissions from peatlands and in particular from drained organic soils. The hypothesis is that drained organic soils react sensitively to changing water content, i.e. that frequent changes of groundwater level enhance the emissions of GHG from these soils and thus contribute significantly to global warming. The area under investigation is based at the Skogaryd Research Catchment (within Swedish Infrastructure for Ecosystem Sciences, SITES) in western Sweden (Meyer, et al., 2013), which was recently assigned the status of a national research site by the Swedish research council (www.vr.se). Skogaryd is a unique place in Sweden for doing research on organic soils as the area was simultaneously afforested in the 1960s and the drained fertile soils have a different land-use history. The ditching for drainage purposes throughout the entire area has had and still has a huge influence on groundwater level, which in turn is assumed to trigger GHG emissions from the organic soils at Skogaryd. To address the influence of groundwater dynamics on GHG emissions in this system, a characterisation of the subsurface using electrical resistivity and Ground Penetrating Radar (GPR) measurements was carried out. These geophysical measurements were combined with drilling along them to allow for ground truthing. An average peat thickness of around 3 m was estimated for the field site. Below the peat follows a fine sand layer, which reaches a maximum thickness of around 1.0 m right at the valley borders and thins out significantly towards the middle of the valley. Below the fine sand layer follows a layer of marine clay, which extends down to the bedrock at depths between 12 and 15 m below ground surface. The results show that the peat layer in Skogaryd forms an isolated hydraulic system without interaction with deeper or regional groundwater systems. The continuously extending clay layer hinders water moving downward or upward crossing the border of peat and clay. The peat layer is a fast reacting hydraulic system that shows immediate reaction to precipitation or drought and is independent from regional groundwater levels. The study of groundwater controls on the GHG from the drained organic soils at Skogaryd can thus focus on the fast reacting peat layer. Future investigations will show if this conclusion can be generalized for similar situations in Sweden. Geophysical measurements have proved to be a valuable method for estimating the peat thickness over a large area. Meyer A, Tarvainen L, Nousratpour A, Björk RG, Ernfors M, Grelle A, Kasimir Klemedtsson Å, Lindroth A, Räntfors M, Rütting T, Wallin G, Weslien P, Klemedtsson L (2013) A fertile peatland forest does not constitute a major greenhouse gas sink. Biogeosciences 10: 7739-7758 DOI 10.5194/bg-10-7739-2013

Assessing tungsten transport in the vadose zone: from dissolution studies to soil columns.

PubMed

Tuna, Gulsah Sen; Braida, Washington; Ogundipe, Adebayo; Strickland, David

2012-03-01

This study investigates the dissolution, sorption, leachability, and plant uptake of tungsten and alloying metals from canister round munitions in the presence of model, well characterized soils. The source of tungsten was canister round munitions, composed mainly of tungsten (95%) with iron and nickel making up the remaining fraction. Three soils were chosen for the lysimeter studies while four model soils were selected for the adsorption studies. Lysimeter soils were representatives of the typical range of soils across the continental USA; muck-peat, clay-loamy and sandy-quartzose soil. Adsorption equilibrium data on the four model soils were modeled with Langmuir and linear isotherms and the model parameters were obtained. The adsorption affinity of soils for tungsten follows the order: Pahokee peat>kaolinite>montmorillonite>illite. A canister round munition dissolution study was also performed. After 24 d, the measured dissolved concentrations were: 61.97, 3.56, 15.83 mg L(-1) for tungsten, iron and nickel, respectively. Lysimeter transport studies show muck peat and sandy quartzose soils having higher tungsten concentration, up to 150 mg kg(-1) in the upper layers of the lysimeters and a sharp decline with depth suggesting strong retardation processes along the soil profile. The concentrations of tungsten, iron and nickel in soil lysimeter effluents were very low in terms of posing any environmental concern; although no regulatory limits have been established for tungsten in natural waters. The substantial uptake of tungsten and nickel by ryegrass after 120 d of exposure to soils containing canister round munition suggests the possibility of tungsten and nickel entering the food chain. Copyright © 2011 Elsevier Ltd. All rights reserved.

Alfred P. Dachnowski and the scientific study of peats

USGS Publications Warehouse

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

2011-01-01

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

Microbial communities and transformation of carbon compounds in bog soils of the taiga zone (Tomsk oblast)

NASA Astrophysics Data System (ADS)

Grodnitskaya, I. D.; Trusova, M. Yu.

2009-09-01

Two types of bogs were studied in Tomsk oblast—Maloe Zhukovskoe (an eutrophic peat low-moor bog) and Ozernoe (an oligotrophic peat high-moor bog). The gram-negative forms of Proteobacteria were found to be dominant and amounted to more than 40% of the total population of the microorganisms investigated. In the peat bogs, the population and diversity of the hydrolytic microbial complex, especially of the number of micromycetes, were lower than those in the mineral soils. The changes in the quantitative indices of the total microbiological activity of the bogs were established. The microbial biomass and the intensity of its respiration differed and were also related to the depth of the sampling. In the Zhukovskoe peat low-moor bog, the maximal biomass of heterotrophic microorganisms (154 μg of C/g of peat) was found in the aerobic zone at a depth of 0 to 10 cm. In the Ozernoe bog, the maximal biomass was determined in the zone of anaerobiosis at a depth of 300 cm (1947 μ g of C/g of peat). The molecular-genetic method was used for the determination of the spectrum of the methanogens. Seven unidentified dominant forms were revealed. The species diversity of the methanogens was higher in the oligotrophic high-moor bog than in the eutrophic low-moor bog.

Lateral carbon fluxes and CO2 outgassing from a tropical peat-draining river

NASA Astrophysics Data System (ADS)

Müller, D.; Warneke, T.; Rixen, T.; Müller, M.; Jamahari, S.; Denis, N.; Mujahid, A.; Notholt, J.

2015-07-01

Tropical peatlands play an important role in the global carbon cycle due to their immense carbon storage capacity. However, pristine peat swamp forests are vanishing due to deforestation and peatland degradation, especially in Southeast Asia. CO2 emissions associated with this land use change might not only come from the peat soil directly, but also from peat-draining rivers. So far, though, this has been mere speculation, since there was no data from undisturbed reference sites. We present the first combined assessment of lateral organic carbon fluxes and CO2 outgassing from an undisturbed tropical peat-draining river. Two sampling campaigns were undertaken on the Maludam river in Sarawak, Malaysia. The river catchment is covered by protected peat swamp forest, offering a unique opportunity to study a peat-draining river in its natural state, without any influence from tributaries with different characteristics. The two campaigns yielded consistent results. Dissolved organic carbon (DOC) concentrations ranged between 3222 and 6218 μmol L-1 and accounted for more than 99 % of the total organic carbon (TOC). Radiocarbon dating revealed that the riverine DOC was of recent origin, suggesting that it derives from the top soil layers and surface runoff. We observed strong oxygen depletion, implying high rates of organic matter decomposition and consequently CO2 production. The measured median pCO2 was 7795 and 8400 μatm during the two campaigns, respectively. Overall, we found that only 26 ± 15 % of the carbon was exported by CO2 evasion, while the rest was exported by discharge. CO2 outgassing seemed to be moderated by the short water residence time. Since most Southeast Asian peatlands are located at the coast, this is probably an important limiting factor for CO2 outgassing from most of its peat-draining rivers.

Stocks and fluxes of carbon associated with land use change in Southeast Asian tropical peatlands: A review

NASA Astrophysics Data System (ADS)

Hergoualc'h, Kristell; Verchot, Louis V.

2011-06-01

The increasing and alarming trend of degradation and deforestation of tropical peat swamp forests may contribute greatly to climate change. Estimates of carbon (C) losses associated with land use change in tropical peatlands are needed. To assess these losses we examined C stocks and peat C fluxes in virgin peat swamp forests and tropical peatlands affected by six common types of land use. Phytomass C loss from the conversion of virgin peat swamp forest to logged forest, fire-damaged forest, mixed croplands and shrublands, rice field, oil palm plantation, and Acacia plantation were calculated using the stock difference method and estimated at 116.9 ± 39.8, 151.6 ± 36.0, 204.1 ± 28.6, 214.9 ± 28.4, 188.1 ± 29.8, and 191.7 ± 28.5 Mg C ha-1, respectively. Total C loss from uncontrolled fires ranged from 289.5 ± 68.1 Mg C ha-1 in rice fields to 436.2 ± 77.0 Mg C ha-1 in virgin peat swamp forest. We assessed the effects of land use change on C stocks in the peat by looking at how the change in vegetation cover altered the main C inputs (litterfall and root mortality) and outputs (heterotrophic respiration, CH4 flux, fires, and soluble and physical removal) before and after conversion. The difference between the soil input-output balances in the virgin peat swamp forest and in the oil palm plantation gave an estimate of peat C loss of 10.8 ± 3.5 Mg C ha-1 yr-1. Peat C loss from other land use conversions could not be assessed due to lack of data, principally on soil heterotrophic respiration rates. Over 25 years, the conversion of tropical virgin peat swamp forest into oil palm plantation represents a total C loss from both biomass and peat of 427.2 ± 90.7 Mg C ha-1 or 17.1 ± 3.6 Mg C ha-1 yr-1. In all situations, peat C loss contributed more than 63% to total C loss, demonstrating the urgent need in terms of the atmospheric greenhouse gas burden to protect tropical virgin peat swamp forests from land use change and fires.

Effects of a raised water table on greenhouse gas emissions and celery yield from agricultural peat under climate warming conditions

NASA Astrophysics Data System (ADS)

Matysek, Magdalena; Zona, Donatella; Leake, Jonathan; Banwart, Steven

2017-04-01

Peatlands are globally important areas for carbon preservation: covering only 3% of world's land, they store 30% of total soil carbon. At the same time, peat soils are widely utilised in agriculture: in Europe 14% of peatland area is under cultivation, 40% of UK peatlands have been drained for agricultural use and 24% of deep peat area in England is being farmed. One of the most important regions for crop production on lowland peats in the UK are the East Anglian Fenlands (the Fens): an area of drained peatlands in East England. 88% of the Fenland area is cultivated, sustaining around 4000 farms and supplying 37% of total vegetable production in England. The soils of the area are fertile (89% of agricultural land being classified as grade 1 or 2) and so crops with high nutritional demands tend to dominate. It is estimated that Fenland peats store 41 Tg of Carbon, which is lost from the ecosystem at a rate of 0.4 Tg C/yr. The Fens are at risk due to continued drainage-induced volume loss of the peat layer via shrinkage, compaction and oxidation, which are estimated to result in wastage rate of 2.1 cm/yr. Cultivation of peat soil requires drainage as most crops are intolerant of root-zone anoxia: this leads to creation of oxic conditions in which organic matter becomes vulnerable to mineralisation by aerobic microorganisms. It is, therefore, crucial to find a water table level which would minimise peat loss and at the same time allow for economically viable crop growth. Despite the importance of preservation of agricultural peats, there is a lack of studies which attempt to find water table level that strikes a balance between crop yield and greenhouse gas production. The future of the Fens is overshadowed by another uncertainty: increases in temperature brought by the climate change. It is estimated that average global temperature increase expected by the end of this century (relative to 1986-2005) would be within the range of 0.3-4.8°C, depending on the scenario. Rising temperatures should accelerate the rate of organic matter mineralisation, which will lead to higher emissions of greenhouse gases as well as enhanced plant growth due to better availability of nutrients. The effects of higher temperatures on crop growth and greenhouse gas emission have not been properly investigated in the context of agriculturally-utilised peatlands. This study was conducted on peat cores excavated from a field in the Fens and focused on the following objectives: 1. To examine effects of climate change-induced temperature rises on celery productivity and peat CO2 and CH4 emissions. 2. To find the field water table level that reduces peat emissions of CO2 and CH4 while maintaining celery productivity. The research found higher CO2 emissions from the elevated (+5°C) temperature treatment and lower CO2 emissions from the higher (-30cm) water table level, however, noted no effect on CH4 emissions of any of the treatments. The higher water table decreased aboveground celery biomass. There was no effect of increased temperature on aboveground celery yield.

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

USDA-ARS?s Scientific Manuscript database

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

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

USDA-ARS?s Scientific Manuscript database

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

Reduction of trichloroethylene and nitrate by zero-valent iron with peat.

PubMed

Min, Jee-Eun; Kim, Meejeong; Pardue, John H; Park, Jae-Woo

2008-02-01

The feasibility of using zero-valent iron (ZVI) and peat mixture as in situ barriers for contaminated sediments and groundwater was investigated. Trichloroethylene (TCE) and nitrate (NO(3)(-)), redox sensitive contaminants were reduced by ZVI and peat soil mixture under anaerobic condition. Peat was used to support the sorption of TCE, microbial activity for biodegradation of TCE and denitrification while TCE and nitrate were reduced by ZVI. Decreases in TCE concentrations were mainly due to ZVI, while peat supported denitrifying microbes and further affected the sorption of TCE. Due to the competition of electrons, nitrate reduction was inhibited by TCE, while TCE reduction was not affected by nitrate. From the results of peat and sterilized peat, it can be concluded that peat was involved in both dechlorination and denitrification but biological reduction of TCE was negligible compared to that of nitrate. The results from hydrogen and methane gas analyses confirmed that hydrogen utilization by microbes and methanogenic process had occurred in the ZVI-peat system. Even though effect of the peat on TCE reduction were quantitatively small, ZVI and peat contributed to the removal of TCE and nitrate independently. The 16S rRNA analysis revealed that viable bacterial diversity was narrow and the most frequently observed genera were Bacillus and Staphylococcus spp.

The change of soil properties after wildfires in drained peatlands (Moscow region, Russia)

NASA Astrophysics Data System (ADS)

Koshovskii, Timur; Tsibart, Anna; Smirnova, Maria; Valentina, Gavrilova; Anna, Kiseleva

2014-05-01

The peat fires differ from the forest and grassland fires, because the soil organic matter acts as burning material. The deep peat horizons are heated or burned during smoldering fires, causing the dramatic change in soil properties. But the most of available data are devoted to changes in organo-mineral soils. In addition, the alteration in hydrological regime, for instance drainage, makes landscapes and soils very vulnerable to wildfires. Drained peatlands are widespread in the European part of Russia and they are affected to extreme wildfires of 2010. So there is a need of post-fire peat soils investigations in this region. During current research the soils of drained peatlands of Moscow Region (Russia) subjected to wildfires of 2002 and 2010 were studied. A total of 14 profiles including background and post-pyrogenic histosols and histic podsols were investigated. Soil samples were taken from genetic horizons and from every 10 cm in cases of thick horizons. The morfological properties of soil profiles were studied and the samples were analysed on macroelements content and organic carbon. The total organic carbon contentrations were detected with spectrofotometric method and the concentrations of macroelements were analysed with X-ray fluorescence method. After wildfires on drained peatlands morfological and physico-chemical properties of soils were changed, the horizons of ash (up to 5 cm) and char (up to 3 cm) instead of organic layers were formed. In addition, the plots of post-pirogenic landscape were characterized by high variability of soil properties. For instance, the thickness of organic layer changed from 5 to 30 cm in a small plot of 5X5 m. The changes in element composition were detected. The peat horizons of background histosols had 80-90% of SiO2, 9-5,8% of Al2O3,1,5-5,6% of Fe2O3, 3,7-6,3% of CaO, 0,7-2,8 % of MnO. Background histic podsols contained 88-90% of SiO2, to 4,8% of Al2O3, and the proportion of Fe2O3 and MnO was about 2,3%. After the fire ash horizons had elevated concentrations of Al2O3 (9-17%), Fe2O3 (4-11%), P2O3 (1-1,8 %), CaO (1,9-2,8 %) and K2O (0,1-1,9%). The char horizons had composition similar to background peat. On the one hand the loss of organic matter took place after burning. But on the other hand after the fire new stage of humus formation started and in 2 years after the burning the content of organic carbon reached up to 10 % in upper horizons.

The effect of wood ash fertilization on soil respiration and tree stand growth in boreal peatland forests

NASA Astrophysics Data System (ADS)

Liimatainen, Maarit; Maljanen, Marja; Hytönen, Jyrki

2017-04-01

Out of Finland's original 10 million hectares of peatlands over half has been drained for forestry. Natural peatlands act as a sink for carbon but when peatland is drained, increased oxygen concentration in the peat accelerates the aerobic decomposition of the old organic matter of the peat leading to carbon dioxide (CO2) emissions to atmosphere. Increasing use of bioenergy increases also the amount of ash produced as a byproduct in power plants. Wood ash contains all essential nutrients for trees to grow except nitrogen. Therefore, wood ash is ideal fertilizer for nitrogen rich peatland forests where lack of phosphorus or potassium may restrict tree growth. At the moment, wood ash is the only available PK-fertilizer for peatland forests in Finland and areas of peatland forests fertilized with ash are increasing annually. The effects of wood ash on vegetation, soil properties and tree growth are rather well known although most of the studies have been made using fine ash whereas nowadays mostly stabilized ash (e.g. granulated) is used. Transporting and spreading of stabilized ash is easier than that of dusty fine ash. Also, slower leaching rate of nutrients is environmentally beneficial and prolongs the fertilizer effect. The knowledge on the impact of granulated wood ash on greenhouse gas emissions is still very limited. The aim of this study was to examine the effects of granulated wood ash on CO2 emissions from peat and tree stand growth. Field measurements were done in two boreal peatland forests in 2011 and 2012. One of the sites is more nutrient rich with soil carbon to nitrogen ratio (C/N) of 18 whereas the other site is nutrient poor with C/N ratio of 82. Both sites were fertilized with granulated wood ash in 2003 (5000 kg ha-1). The effect of fertilization was followed with tree stand measurements conducted 0, 5 and 10 years after the fertilization. The CO2 emissions of the decomposing peat (heterotrophic respiration) were measured from study plots where vegetation and litter were removed to eliminate respiration by vegetation (autotrophic respiration). Roots were cut by installing aluminum tubes into the depth of 30 cm. Emissions were measured with chamber method using portable CO2 analyzer. Soil temperature was measured simultaneously with gas measurements manually from the depth of 5 cm as well as continuously with data loggers embedded into the peat. Annual soil respiration was modelled assuming that emissions change as a function of temperature. According to preliminary results, fertilization with granulated wood ash increased CO2 emissions of the peat significantly, especially in nutrient poor site. Ash fertilization increased also strongly the accumulation of carbon into the trees. Nonetheless, in both sites CO2emissions from decomposing peat where higher than carbon that was stored in biomass. This was the case especially in the nutrient poor site where trees are growing poorly and due to low peat nitrogen content the area is not considered suitable for ash fertilization. However, at the more fertile site both stand C sequestration and soil C efflux increased similarly.

Rheological Properties of Automorphic and Semihydromorphic Cryometamorphic Northern Taiga Soils in Northeastern European Russia (Komi Republic)

NASA Astrophysics Data System (ADS)

Kholopov, Yu. V.; Khaidapova, D. D.; Lapteva, E. M.

2018-04-01

Soil pastes at the water content corresponding to the maximum swelling of samples from different genetic horizons of cryometamorphic soils―surface-gleyic iron-illuvial svetlozem (Folic Albic Stagnosol) and peaty and peat humus-impregnated gleyic svetlozems (Histic Gleyic Stagnosols)―have been studied with an MCR-302 modular rheometer (Anton Paar, Austria). It has been found that the strongest interparticle bonds are formed in the horizons of cryometamorphic soils characterized by high contents of humic substances and organomineral Al-Fe-humus compounds. These are horizons of podzol microprofile (Eg and BHF) in iron-illuvial svetlozem and a humus-impregnated horizon (ELhi,g) in peaty and peat svetlozems. Organomineral Al-Fe-humus compounds, as well as the seasonal freezing of soils, determine the elastic-brittle character of interparticle interactions. The contents of clay fractions, exchangeable bases, and organic and organomineral substances impart viscoelastic properties to these contacts. An enhancement of elastic-brittle properties of soil is observed under the impact of gleying and freezing. The threefold decrease of the structural interaction parameter (∫ Z) when going from automorphic to semihydromorphic conditions indicates a decrease in the resistance of peaty and peat svetlozems to mechanical loads under increasing hydromorphism compared to iron-illuvial svetlozems.

Ideas and perspectives: Holocene thermokarst sediments of the Yedoma permafrost region do not increase the northern peatland carbon pool

NASA Astrophysics Data System (ADS)

Hugelius, Gustaf; Kuhry, Peter; Tarnocai, Charles

2016-04-01

Permafrost deposits in the Beringian Yedoma region store large amounts of organic carbon (OC). Walter Anthony et al. (2014) describe a previously unrecognized pool of 159 Pg OC accumulated in Holocene thermokarst sediments deposited in Yedoma region alases (thermokarst depressions). They claim that these alas sediments increase the previously recognized circumpolar permafrost peat OC pool by 50 %. It is stated that previous integrated studies of the permafrost OC pool have failed to account for these deposits because the Northern Circumpolar Soil Carbon Database (NCSCD) is biased towards non-alas field sites and that the soil maps used in the NCSCD underestimate coverage of organic permafrost soils. Here we evaluate these statements against a brief literature review, existing data sets on Yedoma region soil OC storage and independent field-based and geospatial data sets of peat soil distribution in the Siberian Yedoma region. Our findings are summarized in three main points. Firstly, the sediments described by Walter Anthony et al. (2014) are primarily mineral lake sediments and do not match widely used international scientific definitions of peat or organic soils. They can therefore not be considered an addition to the circumpolar peat carbon pool. We also emphasize that a clear distinction between mineral and organic soil types is important since they show very different vulnerability trajectories under climate change. Secondly, independent field data and geospatial analyses show that the Siberian Yedoma region is dominated by mineral soils, not peatlands. Thus, there is no evidence to suggest any systematic bias in the NCSCD field data or maps. Thirdly, there is spatial overlap between these Holocene thermokarst sediments and previous estimates of permafrost soil and sediment OC stocks. These carbon stocks were already accounted for by previous studies and they do not significantly increase the known circumpolar OC pool. We suggest that these inaccurate statements made in Walter Anthony et al. (2014) mainly resulted from misunderstandings caused by conflicting definitions and terminologies across different geoscientific disciplines. A careful cross-disciplinary review of terminologies would help future studies to appropriately harmonize definitions between different fields.

Oribatid mites in soil toxicity testing-the use of Oppia nitens (C.L. Koch) as a new test species.

PubMed

Princz, Juliska I; Behan-Pelletier, Valerie M; Scroggins, Richard P; Siciliano, Steven D

2010-04-01

Few soil invertebrate species are available for the toxic assessment of soils from boreal or other northern ecozones, yet these soils cover the majority of Canada's landmass as well as significant portions of Eurasia. Oppia nitens (C.L. Koch) is an herbivorous and fungivorous oribatid mite found in soil throughout Holarctic regions, including Canada. Soil tests using O. nitens were performed using 15 different forest soil types and horizons to investigate test variability in adult survival and reproduction. Adult survival (86.1 +/- 1.1%) was consistent across soil types, with a coefficient of variation (CV) of 15%. However, reproduction varied significantly, ranging from 2.9 (+/-1.1) to 86.2 (+/-11.7) individuals, with a corresponding CV of 118 and 30%, respectively. Of the soil factors assessed (NH(3), NO(3), pH, phosphorus [P], organic matter content (OM), carbon:nitrogen (C:N), sand, silt, clay, and sodium adsorption ratio), soil organic matter (OM) explained 68% of the variation observed for reproduction. Increasing the OM using Sphagnum sp. peat moss resulted in optimal reproduction at 7% OM (8% peat content) with the lowest variability (CV of 20%). When assessing the toxicity of a reference chemical, boric acid, the effect of peat amendment reduced lethality to adults with no observable difference on reproduction. The use an age-synchronized culture reduced the test variability for reproduction relative to the use of unsynchronized cultures. Oppia nitens is a good candidate species for a standardized test design, with adult survival easily assessed in a relatively simple design. A long-term reproduction test with O. nitens will require the use of a synchronized population and, on occasion, OM amendment when testing soils with low organic matter content. (c) 2009 SETAC.

Bacterial and Fungal Communities in a Degraded Ombrotrophic Peatland Undergoing Natural and Managed Re-Vegetation

PubMed Central

Elliott, David R.; Caporn, Simon J. M.; Nwaishi, Felix; Nilsson, R. Henrik; Sen, Robin

2015-01-01

The UK hosts 15–19% of global upland ombrotrophic (rain fed) peatlands that are estimated to store 3.2 billion tonnes of carbon and represent a critical upland habitat with regard to biodiversity and ecosystem services provision. Net production is dependent on an imbalance between growth of peat-forming Sphagnum mosses and microbial decomposition by microorganisms that are limited by cold, acidic, and anaerobic conditions. In the Southern Pennines, land-use change, drainage, and over 200 years of anthropogenic N and heavy metal deposition have contributed to severe peatland degradation manifested as a loss of vegetation leaving bare peat susceptible to erosion and deep gullying. A restoration programme designed to regain peat hydrology, stability and functionality has involved re-vegetation through nurse grass, dwarf shrub and Sphagnum re-introduction. Our aim was to characterise bacterial and fungal communities, via high-throughput rRNA gene sequencing, in the surface acrotelm/mesotelm of degraded bare peat, long-term stable vegetated peat, and natural and managed restorations. Compared to long-term vegetated areas the bare peat microbiome had significantly higher levels of oligotrophic marker phyla (Acidobacteria, Verrucomicrobia, TM6) and lower Bacteroidetes and Actinobacteria, together with much higher ligninolytic Basidiomycota. Fewer distinct microbial sequences and significantly fewer cultivable microbes were detected in bare peat compared to other areas. Microbial community structure was linked to restoration activity and correlated with soil edaphic variables (e.g. moisture and heavy metals). Although rapid community changes were evident following restoration activity, restored bare peat did not approach a similar microbial community structure to non-eroded areas even after 25 years, which may be related to the stabilisation of historic deposited heavy metals pollution in long-term stable areas. These primary findings are discussed in relation to bare peat oligotrophy, re-vegetation recalcitrance, rhizosphere-microbe-soil interactions, C, N and P cycling, trajectory of restoration, and ecosystem service implications for peatland restoration. PMID:25969988

Bacterial and fungal communities in a degraded ombrotrophic peatland undergoing natural and managed re-vegetation.

PubMed

Elliott, David R; Caporn, Simon J M; Nwaishi, Felix; Nilsson, R Henrik; Sen, Robin

2015-01-01

The UK hosts 15-19% of global upland ombrotrophic (rain fed) peatlands that are estimated to store 3.2 billion tonnes of carbon and represent a critical upland habitat with regard to biodiversity and ecosystem services provision. Net production is dependent on an imbalance between growth of peat-forming Sphagnum mosses and microbial decomposition by microorganisms that are limited by cold, acidic, and anaerobic conditions. In the Southern Pennines, land-use change, drainage, and over 200 years of anthropogenic N and heavy metal deposition have contributed to severe peatland degradation manifested as a loss of vegetation leaving bare peat susceptible to erosion and deep gullying. A restoration programme designed to regain peat hydrology, stability and functionality has involved re-vegetation through nurse grass, dwarf shrub and Sphagnum re-introduction. Our aim was to characterise bacterial and fungal communities, via high-throughput rRNA gene sequencing, in the surface acrotelm/mesotelm of degraded bare peat, long-term stable vegetated peat, and natural and managed restorations. Compared to long-term vegetated areas the bare peat microbiome had significantly higher levels of oligotrophic marker phyla (Acidobacteria, Verrucomicrobia, TM6) and lower Bacteroidetes and Actinobacteria, together with much higher ligninolytic Basidiomycota. Fewer distinct microbial sequences and significantly fewer cultivable microbes were detected in bare peat compared to other areas. Microbial community structure was linked to restoration activity and correlated with soil edaphic variables (e.g. moisture and heavy metals). Although rapid community changes were evident following restoration activity, restored bare peat did not approach a similar microbial community structure to non-eroded areas even after 25 years, which may be related to the stabilisation of historic deposited heavy metals pollution in long-term stable areas. These primary findings are discussed in relation to bare peat oligotrophy, re-vegetation recalcitrance, rhizosphere-microbe-soil interactions, C, N and P cycling, trajectory of restoration, and ecosystem service implications for peatland restoration.

Deviations from sorption linearity on soils of polar and nonpolar organic compounds at low relative concentrations

USGS Publications Warehouse

Chiou, C.T.; Kile, D.E.

1998-01-01

A series of single-solute and binary-solute sorption data have been obtained on representative samples of polar compounds (substituted ureas and phenolic compounds) and of nonpolar compounds (e.g., EDB and TCE) on a peat soil and a mineral (Woodburn) soil; the data extend to low relative solute concentrations (C(e)/S(w)). At relatively low C(e)/S(w), both the nonpolar and the polar solutes exhibit nonlinear sorption. The sorption nonlinearity approaches apparent saturation at about C(e)/S(w) = 0.010-0.015 for the nonpolar solutes and at about C(e)/S(w) = 0.10-0.13 for the polar solutes; above these C(e)/S(w) regions, the isotherms are practically linear. The nonlinear sorption capacities are greater for polar solutes than for nonpolar solutes and the peat soil shows a greater effect than the Woodburn soil. The small nonlinear sorption capacity for a nonpolar solute is suppressed indiscriminately by either a nonpolar or a polar cosolute at relatively low C(e)/S(w) of the cosolute. By contrast, the abilities of different cosolutes to suppress the nonlinear capacity of a nominal polar solute differ drastically. For polar solutes, a nonpolar cosolute exhibits a limited suppression even at high cosolute C(e)/S(w); effective suppression occurs when the cosolute is relatively polar and at various C(e)/S(w). These differences suggest that more than a single mechanism is required to account for the nonlinear sorption of both nonpolar and polar compounds at low C(e)/S(w). Mechanistic processes consistent with these observations and with soil surface areas are discussed along with other suggested models. Some important consequences of the nonlinear competitive sorption to the behavior of contaminants in natural systems are discussed.A number of conceptual models was postulated to account for the nonlinear solute sorption on soils of significant soil organic matter. A series of single-solute and binary-route sorption data was obtained representing samples of polar compounds of substituted ureas and phenolic compounds, and of nonpolar compounds of EDB and trichloroethylene on a peat soil and a mineral on a Woodburn soil. The nonlinear sorption capacities are greater for polar solutes than for nonpolar solutes and the peat soil shows a greater effect than the Woodburn soil.

Soil property effects on wind erosion of organic soils

USDA-ARS?s Scientific Manuscript database

Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (>20%) in half or more of the upper 80 cm. Forty four states have a total of 21 million ha of histosols in the United States. These soils, when intensively cropped, are subject to wind erosion r...

Soil Property Effects on Wind Erosion of Organic Soils

USDA-ARS?s Scientific Manuscript database

Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (>20%) in half or more of the upper 80 cm. Forty four states have a total of 21 million ha of histosols in the United States. These soils, when intensively cropped, are subject to wind erosion r...

Changing of Sumatra backswamp peat properties by seawater and zeolite application

NASA Astrophysics Data System (ADS)

Sarifuddin; Nasution, Z.; Rauf, A.; Mulyanto, B.

2018-02-01

This research attempts to improve the properties of backswamp peatsoil originated from Asahan District, North Sumatra Indonesia by adding sea water and zeolite using factorial randomized block design with volume of sea water as first factor, consisting of without seawater, 500 ml, 1000 ml and 1500 ml and second factor are dosages of zeolite consisting of without zeolite, 100 g, 200 g each 10 kgs of wet peat soil. at green house in faculty of agriculture University of Sumatra Utara (USU) Medan, Indonesia. The result showed that the application of seawater decreased pH, C/N and Cation Exchange Capacity and increased of base saturation of peat soil. Adding of zeolite minerals can buffered the increasing of acidity and Electric Conductivity caused by sea water application. Interaction seawater + zeolite decreased of C/N and increased of percent of base saturation.

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.

Patterns and drivers of fungal community depth stratification in Sphagnum peat

USDA-ARS?s Scientific Manuscript database

Peatlands store an immense pool of soil carbon vulnerable to microbial oxidation due to drought and intentional draining. We used amplicon sequencing and quantitative PCR to 1) examine how fungi are influenced by depth in the peat profile, water table (WT) and plant functional group (PFG) at the ons...

Forest condition in Latvia

Treesearch

Madis Sipols

1998-01-01

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

Use of Computed Tomography Imaging for Qualifying Coarse Roots, Rhizomes, Peat, and Particle Densities in Marsh Soils

EPA Science Inventory

Computed tomography (CT) imaging has been used to describe and quantify subtidal, benthic animals such as polychaetes, amphipods, and shrimp. Here, for the first time, CT imaging is used to successfully quantify wet mass of coarse roots, rhizomes, and peat in cores collected from...

Erosion of Northern Hemisphere blanket peatlands under 21st-century climate change

NASA Astrophysics Data System (ADS)

Li, Pengfei; Holden, Joseph; Irvine, Brian; Mu, Xingmin

2017-04-01

Peatlands are important terrestrial carbon stores particularly in the Northern Hemisphere. Many peatlands, such as those in the British Isles, Sweden, and Canada, have undergone increased erosion, resulting in degraded water quality and depleted soil carbon stocks. It is unclear how climate change may impact future peat erosion. Here we use a physically based erosion model (Pan-European Soil Erosion Risk Assessment-PEAT), driven by seven different global climate models (GCMs), to predict fluvial blanket peat erosion in the Northern Hemisphere under 21st-century climate change. After an initial decline, total hemispheric blanket peat erosion rates are found to increase during 2070-2099 (2080s) compared with the baseline period (1961-1990) for most of the GCMs. Regional erosion variability is high with changes to baseline ranging between -1.27 and +21.63 t ha-1 yr-1 in the 2080s. These responses are driven by effects of temperature (generally more dominant) and precipitation change on weathering processes. Low-latitude and warm blanket peatlands are at most risk to fluvial erosion under 21st-century climate change.

Transition from a warm and dry to a cold and wet climate in NE China across the Holocene

NASA Astrophysics Data System (ADS)

Zheng, Yanhong; Pancost, Richard D.; Naafs, B. David A.; Li, Qiyuan; Liu, Zhao; Yang, Huan

2018-07-01

Northeast (NE) China lies in the northernmost part of the East Asian Summer monsoon (EASM) region. Although a series of Holocene climatic records have been obtained from lakes and peats in this region, the Holocene hydrological history and its controls remain unclear. More specifically, it is currently debated whether NE China experienced a dry or wet climate during the early Holocene. Here we reconstruct changes in mean annual air temperature and peat soil moisture across the last ∼13,000 year BP using samples from the Gushantun and Hani peat, located in NE China. Our approach is based on the distribution of bacterial branched glycerol dialkyl glycerol tetraethers (brGDGTs) and the abundance of the archaeal isoprenoidal (iso)GDGT crenarchaeol. Using the recently developed peat-specific MAATpeat temperature calibration we find that NE China experienced a relatively warm early Holocene (∼5-7 °C warmer than today), followed by a cooling trend towards modern-day values during the mid- and late Holocene. Moreover, crenarchaeol concentrations, brGDGT-based pH values, and the distribution of 6-methyl brGDGTs, all indicate an increase in soil moisture content from the early to late Holocene in both peats, which is largely consistent with other data from NE China. This trend towards increasing soil moisture/wetter conditions across the Holocene in NE China records contrasts with the trends observed in other parts of the EASM region, which exhibit an early and/or mid-Holocene moisture/precipitation maximum. However, the Holocene soil moisture variations and temperature-moisture relationships (warm-dry and cold-wet) observed in NE China are similar to those observed in the core area of arid central Asia which is dominated by the westerlies. We therefore propose that an increase in the intensity of the westerlies across the Holocene, driven by increasing winter insolation, expanding Arctic sea ice extent and the enhanced Okhotsk High, caused an increase in moisture during the late Holocene in NE China.

Effects of addition of straw, chitin and manure to new or recycled biofilters on their pesticides retention and degradation properties.

PubMed

Genot, P; Van Huynh, N; Debongnie, Ph; Pussemier, L

2002-01-01

Pollution of surface and groundwater by pesticides is an increasing problem that needs to be addressed by the authorities as well as by the farmers themselves. Nowadays, some researchers are considering the numerous small spillages at the farm sites as a relevant entry route to be taken into account for predicting surface and groundwater pollution. In order to tackle this problem, several solutions exist for limiting the disposal of pesticide wastes into the environment. One such system is biopurification of farm wastes by biobed, biofilter or phytobac. In this study, the results of pesticides retention by biofilters under outdoor conditions are presented. The biofilters were filled with a mixture of a soil + peat constituent (25% by volume for each of them) and the rest (50%) with straw or with composted manure ot with chitin (in this later case at the rate of 5 g chitin per liter of substrate). The soil + peat constituent was made either of a material already challenged by pesticides (= recycled biofilters) or of untreated material (new biofilters). Selected pesticides (atrazine, carbofuran, chloridazon, chlortoluron, cyanazine, isoproturon and lenacil) were applied onto biofilters and the eluates were collected and analyzed. Two successive injections of pesticides into the biofilters were conducted. After the first pesticides application, the recycled biofilters made of soil + peat previously treated with pesticides had better retention and degradation rates than the new biofilters. Adding manure also improved these properties of biofilters. Columns made of unchallenged soil + peat and straw (new biofilters) were the least satisfactory: up to 25% of carbofuran were lost. Biofilters made of unchallenged soil + peat and chitin retained the least lenacil. Atrazine was the most retained by biofilters (either new or recycled) with added chitin. Cyanazine was almost absent in the percolates of all biofilters. After the second application of carbofuran and isoproturon, all biofilters improved to the point where (with the exception the new biofilters made of chitin) they retained the totality of the pesticides.

Utilization of peatlands as possible land resource for low-input agriculture: cultivation of Vaccinium species as an example

NASA Astrophysics Data System (ADS)

Tonutare, Tonu; Rodima, Ako; Rannik, Kaire; Shanskiy, Merrit

2013-04-01

The best way of soil protection is its sustainable and expedient use, which secures soils ecological functioning. Recent years, by exploitation of peat soils for their different use, has raised important issues concerning their input to global climate change as important source of greenhouse gases (GHG) emitters. The dynamics of GHG are determined by different factors as: site specific conditions including hydrology, soil type, vegetation, area management, including meteorological and climatic conditions. Therefore, in this current paper we are presenting the study results were we estimated CO2, CH4 and N2O emissions from exhausted cultivated peatland with Vaccinium species and determined the soil chemical composition. For comparision a virgin state peatland was observed. The main goals of the paper are: (1) to present the experimental results of greenhouse gases generation and peat chemical composition (antioxidant activity of peat, C/N ratio, fiber content, water extractable phenolics) relationships on different microsites either on natural plant cover or Vaccinium species cultivation area on exhausted milled peat area; (2) to discuss how peat soil quality contributes to greenhouse gases emission; (3) and what kind of relationship reveals between low input agricultural system in which Vaccinium species are cultivated on exhausted milled peat area. The study are is located in nearby Ilmatsalu (58°23'N, 26°31'E) in South Estonia, inside of which the three microsites are determined. Microsites are different from each other by exploitation and plant cover type. 1). Natural plant cover, 2). Cultivated area with Vaccinium angustifolium x V. corymbosum, 3). Cultivated area with Vaccinium angustifolium. The determined soil type according to WRB was Fibri Dystric Histosol. The main part of study focuses on the analyses of greenhouse gases. For this purpose the closed chamber method was used. The greenhouse gas samples were collected from spring to autumn 2011 throughout the vegetation period and analyzed in laboratory by GC. In June 2011 the soil samples were collected and chemical composition analyzed for Ntot, Corg, and related plant available nutrients, dry matter and ash content. Also, the water extractable phenolics were measured and the cellulose and lignin content was determined. Along the microsites the ratios of carbon to nitrogen (C/N) and of lignin to nitrogen (L/N) were calculated.. The higher CO2 emission rate in the period from June to August was obtained from the natural plant cover area (range from 322 up to 517 mg/m2h). The emission rate from cultivated area with Vaccinium angustifolium x V. corymbosum was 67-305, from area with Vaccinium angustifolium was 17 - 324 mg/m2h. The maximum emission in October (67 mg/m2h) was recorded from the cultivated area with Vaccinium angustifolium x V. corymbosum plant cover area. During the whole period of measurements the higher methane emission rate was observed from area with natural plant cover - 18-189 μg/m2h. In the same time the lowest emission of N2O was produced on the natural plant cover area. Based on preliminary results we may conclude that greenhouse gas emissions from peat is dependent on the specific pedo-ecological conditions.

High emissions of greenhouse gases from grasslands on peat and other organic soils.

PubMed

Tiemeyer, Bärbel; Albiac Borraz, Elisa; Augustin, Jürgen; Bechtold, Michel; Beetz, Sascha; Beyer, Colja; Drösler, Matthias; Ebli, Martin; Eickenscheidt, Tim; Fiedler, Sabine; Förster, Christoph; Freibauer, Annette; Giebels, Michael; Glatzel, Stephan; Heinichen, Jan; Hoffmann, Mathias; Höper, Heinrich; Jurasinski, Gerald; Leiber-Sauheitl, Katharina; Peichl-Brak, Mandy; Roßkopf, Niko; Sommer, Michael; Zeitz, Jutta

2016-12-01

Drainage has turned peatlands from a carbon sink into one of the world's largest greenhouse gas (GHG) sources from cultivated soils. We analyzed a unique data set (12 peatlands, 48 sites and 122 annual budgets) of mainly unpublished GHG emissions from grasslands on bog and fen peat as well as other soils rich in soil organic carbon (SOC) in Germany. Emissions and environmental variables were measured with identical methods. Site-averaged GHG budgets were surprisingly variable (29.2 ± 17.4 t CO 2 -eq. ha -1  yr -1 ) and partially higher than all published data and the IPCC default emission factors for GHG inventories. Generally, CO 2 (27.7 ± 17.3 t CO 2  ha -1  yr -1 ) dominated the GHG budget. Nitrous oxide (2.3 ± 2.4 kg N 2 O-N ha -1  yr -1 ) and methane emissions (30.8 ± 69.8 kg CH 4 -C ha -1  yr -1 ) were lower than expected except for CH 4 emissions from nutrient-poor acidic sites. At single peatlands, CO 2 emissions clearly increased with deeper mean water table depth (WTD), but there was no general dependency of CO 2 on WTD for the complete data set. Thus, regionalization of CO 2 emissions by WTD only will remain uncertain. WTD dynamics explained some of the differences between peatlands as sites which became very dry during summer showed lower emissions. We introduced the aerated nitrogen stock (N air ) as a variable combining soil nitrogen stocks with WTD. CO 2 increased with N air across peatlands. Soils with comparatively low SOC concentrations showed as high CO 2 emissions as true peat soils because N air was similar. N 2 O emissions were controlled by the WTD dynamics and the nitrogen content of the topsoil. CH 4 emissions can be well described by WTD and ponding duration during summer. Our results can help both to improve GHG emission reporting and to prioritize and plan emission reduction measures for peat and similar soils at different scales. © 2016 John Wiley & Sons Ltd.

Utilization of subsurface microbial electrochemical systems to elucidate the mechanisms of competition between methanogenesis and microbial iron(III)/humic acid reduction in Arctic peat soils

NASA Astrophysics Data System (ADS)

Friedman, E. S.; Miller, K.; Lipson, D.; Angenent, L. T.

2012-12-01

High-latitude peat soils are a major carbon reservoir, and there is growing concern that previously dormant carbon from this reservoir could be released to the atmosphere as a result of continued climate change. Microbial processes, such as methanogenesis and carbon dioxide production via iron(III) or humic acid reduction, are at the heart of the carbon cycle in Arctic peat soils [1]. A deeper understanding of the factors governing microbial dominance in these soils is crucial for predicting the effects of continued climate change. In previous years, we have demonstrated the viability of a potentiostatically-controlled subsurface microbial electrochemical system-based biosensor that measures microbial respiration via exocellular electron transfer [2]. This system utilizes a graphite working electrode poised at 0.1 V NHE to mimic ferric iron and humic acid compounds. Microbes that would normally utilize these compounds as electron acceptors donate electrons to the electrode instead. The resulting current is a measure of microbial respiration with the electrode and is recorded with respect to time. Here, we examine the mechanistic relationship between methanogenesis and iron(III)- or humic acid-reduction by using these same microbial-three electrode systems to provide an inexhaustible source of alternate electron acceptor to microbes in these soils. Chamber-based carbon dioxide and methane fluxes were measured from soil collars with and without microbial three-electrode systems over a period of four weeks. In addition, in some collars we simulated increased fermentation by applying acetate treatments to understand possible effects of continued climate change on microbial processes in these carbon-rich soils. The results from this work aim to increase our fundamental understanding of competition between electron acceptors, and will provide valuable data for climate modeling scenarios. 1. Lipson, D.A., et al., Reduction of iron (III) and humic substances plays a major role in anaerobic respiration in an Arctic peat soil. Journal of Geophysical Research-Biogeosciences, 2010. 115. 2. Friedman, E.S., et al., A cost-effective and field-ready potentiostat that poises subsurface electrodes to monitor bacterial respiration. Biosensors and Bioelectronics, 2012. 32(1): p. 309-313.

Relationship between selected physicochemical properties of peaty-mucks soils and main absorbance bands of its FTIR spectra*

NASA Astrophysics Data System (ADS)

Boguta, Patrycja; Sokolowska, Zofia

2013-04-01

Peatlands are a large reservoir of organic matter that is responsible for sorption properties, structure of soils and microbial activity. However, most of the peatlands in Poland have been drained and subjected to agricultural use. Processes of such kind cause acceleration of peat mass transformation to mucks. Changes in peat evolution under melioration processes are mostly characterised by mineralisation and humification. The above processes lead to changes in the morphological, chemical, biological and physical properties of peat soils. Knowledge about changes of these parameters is very important in suitable application of conditions and fertilisers in order to improve agricultural value of soil. One of the indicators which could describe the changes in peat mass could be the water holding capacity index proposed by Gawlik. This parameter characterises the secondary transformation processes taking place in soils. Mucking processes are also well described by humification indexes and organic/inorganic carbon content. However, changes of above physical and physicochemical properties of soils are also connected with changes of chemical structure of organic matter contained in soil material. Organic matter is a significant component of organic soils and it influences such important parameters of all soil like sorptivity. So that, it is also valuable to control state of functional groups which determine sorption capacity of soil. One of the methods which could be applied in this case is observation of absorbance values of functional groups in infrared spectra of samples. This is quick and method but it could be used only in approximate way because of some content of ash and inorganic parts. Main aim of this work was attempt to find relationships beetwen selected physicochemical properties of peats soils and height of the most important infrared bands of these materials. 11 peaty-muck soils were taken from different places in Eastern part of Poland from deph 0-20cm. After homogenizing, selected parameters were determined for all samples. Content of organic carbon was investigated using TOC analyzer (MultiNC 2000, Analityk Jena), water holding capacity indexes were determined via centrifugation/ weighting method proposed by Gawlik, humification index was calculated using colorimetric method proposed by Springer. Infrared spectra were recorded for samples in form of pellets with KBr. Absorbance of the most important bands were measured: carboxylic for COO- as. (1619-1639cm-1), COO- sym. (1383 - 1387cm-1), COOH sym. (1240 - 1266cm-1) and phenolic groups for (~3389-3401cm-1). After this, relationships between all parameters were found. Results showed presence of statistically significant correlation between absorbance of functional groups and organic carbon content. This relation indicated that increase in organic carbon caused increase in functional groups of organic matter. No statistically significant correlation was found for relation of bands height and water holding capacity and humification index. *This work was partly supported by the National Science Centre in Poland, grant No. UMO-2011/03/N/NZ9/04239.

Carbon stocks and fluxes in managed peatlands in northern Borneo

NASA Astrophysics Data System (ADS)

Arn Teh, Yit; Manning, Frances; Cook, Sarah; Zin Zawawi, Norliyana; Sii, Longwin; Hill, Timothy; Page, Susan; Whelan, Mick; Evans, Chris; Gauci, Vincent; Chocholek, Melanie; Khoon Kho, Lip

2017-04-01

Oil palm is the largest agricultural crop in the tropics and accounts for 13 % of current tropical land area. Patterns of land-atmosphere exchange from oil palm ecosystems therefore have potentially important implications for regional and global C budgets due to the large scale of land conversion. This is particularly true for oil palm plantations on peat because of the large C stocks held by tropical peat soils that are potential sensitivity to human disturbance. Here we report preliminary findings on C stocks and fluxes from a long-term, multi-scale project in Sarawak, Malaysia that aims to quantify the impacts of oil palm conversion on C and greenhouse gas fluxes from oil palm recently established on peat. Land-atmosphere fluxes were determined using a combination of top-down and bottom-up methods (eddy covariance, canopy/stem and soil flux measurements, net primary productivity). Fluvial fluxes were determined by quantifying rates of dissolved and particulate organic C export. Ecosystem C dynamics were determined using the intensive C plot method, which quantified all major C stocks and fluxes, including plant and soil stocks, leaf litterfall, aboveground biomass production, root production, stem/canopy respiration, root-rhizosphere respiration, and heterotrophic soil respiration. Preliminary analysis indicates that vegetative aboveground biomass in these 7 year old plantations was 8.9-11.9 Mg C ha-1, or approximately one-quarter of adjacent secondary forest. Belowground biomass was 5.6-6.5 Mg C ha-1; on par with secondary forests. Soil C stocks in the 0-30 cm depth was 233.1-240.8 Mg C ha-1, or 32-36% greater than soil C stocks in secondary forests at the same depth (176.8 Mg C ha-1). Estimates of vegetative aboveground and belowground net primary productivity were 1.3-1.7 Mg C ha-1 yr-1 and 0.8-0.9 Mg C ha-1 yr-1, respectively. Fruit brunch production was approximately 67 Mg C ha-1over 7 yearsor 9.6 Mg C ha-1 yr-1. Total soil respiration rates were 18 Mg C ha-1 yr-1, with 26 % accounted for by root-rhizosphere respiration and 74 % from heterotrophic soil respiration. This translates to a peat mineralization rate of 10 to 17 Mg C ha-1 yr-1 in the upper 35 cm soil depth above the water table. Fluvial C fluxes were 1.9 Mg C ha-1yr-1, or roughly three times the flux from secondary forest. Findings from the partitioned soil respiration and fluvial flux measurements indicate that peat mineralization may be occurring. However, it is unclear if this represents a net loss of C from the ecosystem, due to the apparent increase in soil C stocks following land conversion, rather than an expected net reduction in soil C. This unexpected finding implies that other processes may be offsetting C losses from heterotrophic decay and fluvial exchange.

Soil Organic Matter and Soil Productivity: Searching for the Missing Link

Treesearch

Felipe G. Sanchez

1998-01-01

Soil-organic matter (SOM) is a complex array of components including soil fauna and flora at different stages of decomposition (Berg et al., 1982). Its concentration in soils can vary from 0.5% in mineral soils to almost 100% in peat soils (Brady, 1974). Organic matter (OM) in the surface mineral soil is considered a major determinant of forest ecosystem productivity...

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

PubMed

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

2017-01-01

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

Estimation of carbon emission from peatland fires using Landsat-8 OLI imagery in Siak District, Riau Province

NASA Astrophysics Data System (ADS)

Aisyah Fadhillah Hafni, Dinda; Syaufina, Lailan; Puspaningsih, Nining; Prasasti, Indah

2018-05-01

The study was conducted in three land cover conditions (secondary peat forest, shrub land, and palm plantation) that were burned in the Siak District, Riau Province, Indonesia year 2015. Measurement and calculation carbon emission from soil and vegetation of peatland should be done accurately to be implemented on climate change mitigation or greenhouse gases mitigation. The objective of the study was to estimate the carbon emission caused peatland fires in the Siak District, Riau Province, Indonesia year 2015. Estimated carbon emissions were performed using visual method and digital method. The visual method was a method that uses on-screen digitization assisted by hotspot data, the presence of smoke, and fire suppression data. The digital method was a method that uses the Normalized Burn Ratio (NBR) index. The estimated carbon emissions were calculated using the equation that was developed from IPCC 2006 in Verified Carbon Standard 2015. The results showed that the estimation of carbon emissions from fires from above the peat soil surface were higher than the carbon emissions from the peat soil. Carbon emissions above the peat soil surface of 1376.51 ton C/ha were obtained by visual method while 3984.33 ton C/ha were obtained by digital method. Peatland carbon emissions of 6.6 x 10-4 ton C/ha were obtained by visual method, whereas 2.84 x 10-3 ton C/ha was obtained by digital method. Visual method and digital method using remote sensing must be combined and developed in order to carbon emission values will be more accurate.

Caribbean mangroves adjust to rising sea level through biotic controls on change in soil elevation

USGS Publications Warehouse

McKee, K.L.; Cahoon, D.R.; Feller, Ilka C.

2007-01-01

Aim The long-term stability of coastal ecosystems such as mangroves and salt marshes depends upon the maintenance of soil elevations within the intertidal habitat as sea level changes. We examined the rates and processes of peat formation by mangroves of the Caribbean Region to better understand biological controls on habitat stability. Location Mangrove-dominated islands on the Caribbean coasts of Belize, Honduras and Panama were selected as study sites. Methods Biological processes controlling mangrove peat formation were manipulated (in Belize) by the addition of nutrients (nitrogen or phosphorus) to Rhizophora mangle (red mangrove), and the effects on the dynamics of soil elevation were determined over a 3-year period using rod surface elevation tables (RSET) and marker horizons. Peat composition and geological accretion rates were determined at all sites using radiocarbon-dated cores. Results The addition of nutrients to mangroves caused significant changes in rates of mangrove root accumulation, which influenced both the rate and direction of change in elevation. Areas with low root input lost elevation and those with high rates gained elevation. These findings were consistent with peat analyses at multiple Caribbean sites showing that deposits (up to 10 m in depth) were composed primarily of mangrove root matter. Comparison of radiocarbon-dated cores at the study sites with a sea-level curve for the western Atlantic indicated a tight coupling between peat building in Caribbean mangroves and sea-level rise over the Holocene. Main conclusions Mangroves common to the Caribbean region have adjusted to changing sea level mainly through subsurface accumulation of refractory mangrove roots. Without root and other organic inputs, submergence of these tidal forests is inevitable due to peat decomposition, physical compaction and eustatic sea-level rise. These findings have relevance for predicting the effects of sea-level rise and biophysical processes on tropical mangrove ecosystems.

Can carbon offsetting pay for upland ecological restoration?

NASA Astrophysics Data System (ADS)

Worrall, F.

2012-04-01

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. However, not all interventions resulted in a benefit; some resulted in increased losses of CO2 equivalents. 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. However, this percentage is very dependent upon the price of carbon used.

Complexes of the antimicrobial ciprofloxacin with soil, peat, and aquatic humic substances.

PubMed

Aristilde, Ludmilla; Sposito, Garrison

2013-07-01

Natural organic matter (NOM) is implicated in the binding of antibiotics by particles in soils and waters. The authors' previous computational study revealed structural rearrangement of both hydrophilic and hydrophobic moieties of NOM to favor H-bonding and other intermolecular interactions, as well as both competition with ion-exchange reactions and bridging interactions by NOM-bound divalent cations. The importance of these interactions was investigated using fluorescence-quenching spectroscopy to study the adsorption of ciprofloxacin (Cipro), a fluoroquinolone antibiotic, on 4 reference humic substances (HSs): Elliott soil humic acid (HA), Pahokee peat HA, and Suwannee river HA and fulvic acid. A simple affinity spectrum HS model was developed to characterize the cation-exchange capacity and the amount of H-bond donor moieties as a function of pH. The adsorption results stress the influence of both pH conditions and the type of HS: both soil HA and peat HA exhibited up to 3 times higher sorption capacity than the aquatic HS at pH ≥ 6, normalizing to the aromatic C content accounted for the differences among the terrestrial HS, and increasing the concentration of divalent cations led to a decrease in adsorption on aquatic HA but not on soil HA. In addition, the pH-dependent speciation models of the Cipro-HS complexes illustrate an increase in complexation due to an increase in deprotonation of HS ligands with increasing pH and, at circumneutral and alkaline pH, enhanced complexation of zwitterionic Cipro only in the presence of soil HA and peat HA. The findings of the present study imply that, in addition to electrostatic interactions, van der Waals interactions as facilitated by aromatic structures and H-bond donating moieties in terrestrial HS may facilitate a favorable binding environment. Environ Toxicol Chem 2013;32:1467-1478. © 2013 SETAC. Copyright © 2013 SETAC.

Innovative biocatalytic production of soil substrate from green waste compost as a sustainable peat substitute.

PubMed

Kazamias, Georgios; Roulia, Maria; Kapsimali, Ioanna; Chassapis, Konstantinos

2017-12-01

In the present work, a new simple and quick eco-friendly method is discussed to handle effectively the green wastes and produce a sustainable peat substitute of high quality on the large scale. Principal physicochemical parameters, i.e., temperature, moisture, specific weight, pH, electrical conductivity and, also, microorganisms, organic matter, humic substances, total Kjeldahl nitrogen and total organic carbon, C/N ratio, ash, metal content and phytotoxicity, were monitored systematically. Humic substances content values were interrelated to both C/N ratio and pH values and, similarly, bulk density, TOC, TKN, C/N, GI, ash and organic matter were found interconnected to each other. A novel biocatalyst, extremely rich in soil microorganisms, prepared from compost extracts and peaty lignite, accelerated the biotransformation. Zeolite was also employed. The compost does not demonstrate any phytotoxicity throughout the entire biotransformation process and has increased humic substances content. Both humic substances content and germination index can be employed as maturation indices of the compost. Addition of compost, processed for 60 days only, in cultivations of grass plants led to a significant increase in the stem mass and root size, annotating the significant contribution of the compost to both growth and germination. The product obtained is comparable to peat humus, useful as peat substitute and can be classified as a first class soil conditioner suitable for organic farming. Copyright © 2016 Elsevier Ltd. All rights reserved.

Soil Carbon Chemistry and Greenhouse Gas Production in Global Peatlands

NASA Astrophysics Data System (ADS)

Normand, A. E.; Turner, B. L.; Lamit, L. J.; Smith, A. N.; Baiser, B.; Clark, M. W.; Hazlett, C.; Lilleskov, E.; Long, J.; Grover, S.; Reddy, K. R.

2017-12-01

Peatlands play a critical role in the global carbon cycle because they contain approximately 30% of the 1500 Pg of carbon stored in soils worldwide. However, the stability of these vast stores of carbon is under threat from climate and land-use change, with important consequences for global climate. Ecosystem models predict the impact of peatland perturbation on carbon fluxes based on total soil carbon pools, but responses could vary markedly depending on the chemical composition of soil organic matter. Here we combine experimental and observational studies to quantify the chemical nature and response to perturbation of soil organic matter in peatlands worldwide. We quantified carbon functional groups in a global sample of 125 freshwater peatlands using solid-state 13C nuclear magnetic resonance (NMR) spectroscopy to determine the drivers of molecular composition of soil organic matter. We then incubated a representative subset of the soils under aerobic and anaerobic conditions to determine how organic matter composition influences carbon dioxide (CO2) and methane (CH4) emissions following drainage or flooding. The functional chemistry of peat varied markedly at large and small spatial scales, due to long-term land use change, mean annual temperature, nutrient status, and vegetation, but not pH. Despite this variation, we found predictable responses of greenhouse gas production following drainage based on soil carbon chemistry, defined by a novel Global Peat Stability Index, with greater CO2 and CH4 fluxes from soils enriched in oxygen-containing organic carbon (O-alkyl C) and depleted in aromatic and hydrophobic compounds. Incorporation of the Global Peat Stability Index of peatland organic matter into earth system models and management strategies, which will improve estimates of GHG fluxes from peatlands and ultimately advance management to reduce carbon loss from these sensitive ecosystems.

Below the disappearing marshes of an urban estuary: historic nitrogen trends and soil structure

USGS Publications Warehouse

Wigand, Cathleen; Roman, Charles T.; Davey, Earl; Stolt, Mark; Johnson, Roxanne; Hanson, Alana; Watson, Elizabeth B.; Moran, S. Bradley; Cahoon, Donald R.; Lynch, James C.; Rafferty, Patricia

2014-01-01

Marshes in the urban Jamaica Bay Estuary, New York, USA are disappearing at an average rate of 13 ha/yr, and multiple stressors (e.g., wastewater inputs, dredging activities, groundwater removal, and global warming) may be contributing to marsh losses. Among these stressors, wastewater nutrients are suspected to be an important contributing cause of marsh deterioration. We used census data, radiometric dating, stable nitrogen isotopes, and soil surveys to examine the temporal relationships between human population growth and soil nitrogen; and we evaluated soil structure with computer-aided tomography, surface elevation and sediment accretion trends, carbon dioxide emissions, and soil shear strength to examine differences among disappearing (Black Bank and Big Egg) and stable marshes (JoCo). Radiometric dating and nitrogen isotope analyses suggested a rapid increase in human wastewater nutrients beginning in the late 1840s, and a tapering off beginning in the 1930s when wastewater treatment plants (WWTPs) were first installed. Current WWTPs nutrient loads to Jamaica Bay are approximately 13 995 kg N/d and 2767 kg P/d. At Black Bank, the biomass and abundance of roots and rhizomes and percentage of organic matter on soil were significantly lower, rhizomes larger in diameter, carbon dioxide emission rates and peat particle density significantly greater, and soil strength significantly lower compared to the stable JoCo Marsh, suggesting Black Bank has elevated decomposition rates, more decomposed peat, and highly waterlogged peat. Despite these differences, the rates of accretion and surface elevation change were similar for both marshes, and the rates of elevation change approximated the long term relative rate of sea level rise estimated from tide gauge data at nearby Sandy Hook, New Jersey. We hypothesize that Black Bank marsh kept pace with sea level rise by the accretion of material on the marsh surface, and the maintenance of soil volume through production of larger diameter rhizomes and swelling (dilation) of waterlogged peat. JoCo Marsh kept pace with sea-level rise through surface accretion and soil organic matter accumulation. Understanding the effects of multiple stressors, including nutrient enrichment, on soil structure, organic matter accumulation, and elevation change will better inform management decisions aimed at maintaining and restoring coastal marshes.

Below the disappearing marshes of an urban estuary: historic nitrogen trends and soil structure.

PubMed

Wigand, Cathleen; Roman, Charles T; Davey, Earl; Stolt, Mark; Johnson, Roxanne; Hanson, Alana; Watson, Elizabeth B; Moran, S Bradley; Cahoon, Donald R; Lynch, James C; Rafferty, Patricia

2014-06-01

Marshes in the urban Jamaica Bay Estuary, New York, USA are disappearing at an average rate of 13 ha/yr, and multiple stressors (e.g., wastewater inputs, dredging activities, groundwater removal, and global warming) may be contributing to marsh losses. Among these stressors, wastewater nutrients are suspected to be an important contributing cause of marsh deterioration. We used census data, radiometric dating, stable nitrogen isotopes, and soil surveys to examine the temporal relationships between human population growth and soil nitrogen; and we evaluated soil structure with computer-aided tomography, surface elevation and sediment accretion trends, carbon dioxide emissions, and soil shear strength to examine differences among disappearing (Black Bank and Big Egg) and stable marshes (JoCo). Radiometric dating and nitrogen isotope analyses suggested a rapid increase in human wastewater nutrients beginning in the late 1840s, and a tapering off beginning in the 1930s when wastewater treatment plants (WWTPs) were first installed. Current WWTPs nutrient loads to Jamaica Bay are approximately 13 995 kg N/d and 2767 kg P/d. At Black Bank, the biomass and abundance of roots and rhizomes and percentage of organic matter on soil were significantly lower, rhizomes larger in diameter, carbon dioxide emission rates and peat particle density significantly greater, and soil strength significantly lower compared to the stable JoCo Marsh, suggesting Black Bank has elevated decomposition rates, more decomposed peat, and highly waterlogged peat. Despite these differences, the rates of accretion and surface elevation change were similar for both marshes, and the rates of elevation change approximated the long-term relative rate of sea level rise estimated from tide gauge data at nearby Sandy Hook, New Jersey. We hypothesize that Black Bank marsh kept pace with sea level rise by the accretion of material on the marsh surface, and the maintenance of soil volume through production of larger diameter rhizomes and swelling (dilation) of waterlogged peat. JoCo Marsh kept pace with sea-level rise through surface accretion and soil organic matter accumulation. Understanding the effects of multiple stressors, including nutrient enrichment, on soil structure, organic matter accumulation, and elevation change will better inform management decisions aimed at maintaining and restoring coastal marshes.

Thermal diffusivity of peat, sand and their mixtures at different water contents

NASA Astrophysics Data System (ADS)

Gvozdkova, Anna; Arkhangelskaya, Tatiana

2014-05-01

Thermal diffusivity of peat, sand and their mixtures at different water contents was studied using the unsteady-state method described in (Parikh et al., 1979). Volume sand content in studied samples was 0 % (pure peat), 5, 10, 15, 20, 30, 40, 50, 55 and 62 % (pure sand). Thermal diffusivity of air-dry samples varied from 0.6×10-7m2s-1 for pure peat to 7.0×10-7m2s-1 for pure sand. Adding 5 and 10 vol. % of sand didn't change the thermal diffusivity of studied mixture as compared with that of the pure air-dry peat. Adding 15 % of sand resulted in significant increase of thermal diffusivity by approximately 1.5 times: from 0.6×10-7m2s-1 to 0.9×10-7m2s-1. It means that small amounts of sand with separate sand particles distributed within the peat don't contribute much to the heat transfer through the studied media. And there is a kind of threshold between the 10 and 15 vol. % of sand, after which the continuous sandy chains are formed within the peat, which can serve as preferential paths of heat transport. Adding 20 and 30 % of sand resulted in further increase of thermal diffusivity to 1.3×10-7m2s-1 and 1.7×10-7m2s-1, which is more than two and three times greater than the initial value for pure peat. Thermal diffusivity vs. moisture content dependencies had different shapes. For sand contents of 0 to 40 vol. % the thermal diffusivity increased with water content in the whole studied range from air-dry samples to the capillary moistened ones. For pure peat the experimental curves were almost linear; the more sand was added the more pronounced became the S-shape of the curves. For sand contents of 50 % and more the curves had a pronounced maximum within the range of water contents between 0.10 and 0.25 m3m-3 and then decreased. The experimental k(θ) curves, where k is soil thermal diffusivity, θ is water content, were parameterized with a 4-parameter approximating function (Arkhangelskaya, 2009, 2014). The suggested approximation has an advantage of clear physical interpretation: the parameters are (1) the thermal diffusivity of the dry sample; (2) the difference between the highest thermal diffusivity at some optional water content and that of the dry sample; (3) the optional water content at which the thermal diffusivity reaches its maximum; (4) half-width of the peak of the k(θ) curve. The increase of sand contents in studied mixtures was accompanied by the increase of the parameters (1), (2) and (4) and the decrease of the parameter (3). References Parikh R.J., Havens J.A., Scott H.D., 1979. Thermal diffusivity and conductivity of moist porous media. Soil Science Society of America Journal 43, 1050-1052. Arkhangel'skaya T.A., 2009. Parameterization and mathematical modeling of the dependence of soil thermal diffusivity on the water content. Eurasian Soil Science 42 (2), 162-172. doi: 10.1134/S1064229309020070 Arkhangelskaya T.A., 2014. Diversity of thermal conditions within the paleocryogenic soil complexes of the East European Plain: The discussion of key factors and mathematical modeling // Geoderma. Vol. 213. P. 608-616. doi 10.1016/j.geoderma.2013.04.001

Forests on drained agricultural peatland are potentially large sources of greenhouse gases - insights from a full rotation period simulation

NASA Astrophysics Data System (ADS)

He, Hongxing; Jansson, Per-Erik; Svensson, Magnus; Björklund, Jesper; Tarvainen, Lasse; Klemedtsson, Leif; Kasimir, Åsa

2016-04-01

The CoupModel was used to simulate a Norway spruce forest on fertile drained peat over 60 years, from planting in 1951 until 2011, describing abiotic, biotic and greenhouse gas (GHG) emissions (CO2 and N2O). By calibrating the model against tree ring data a "vegetation fitted" model was obtained by which we were able to describe the fluxes and controlling factors over the 60 years. We discuss some conceptual issues relevant to improving the model in order to better understand peat soil simulations. However, the present model was able to describe the most important ecosystem dynamics such as the plant biomass development and GHG emissions. The GHG fluxes are composed of two important quantities, the spruce forest carbon (C) uptake, 413 g C m-2 yr-1 and the decomposition of peat soil, 399 g C m-2 yr-1. N2O emissions contribute to the GHG emissions by up to 0.7 g N m-2 yr-1, corresponding to 76 g C m-2 yr-1. The 60-year old spruce forest has an accumulated biomass of 16.0 kg C m-2 (corresponding to 60 kg CO2 m-2). However, over this period, 26.4 kg C m-2 (97 kg CO2eq m-2) has been added to the atmosphere, as both CO2 and N2O originating from the peat soil and, indirectly, from forest thinning products, which we assume have a short lifetime. We conclude that after harvest at an age of 80 years, most of the stored biomass carbon is liable to be released, the system having captured C only temporarily and with a cost of disappeared peat, adding CO2 to the atmosphere.

Forests on drained agricultural peatland are potentially large sources of greenhouse gases - insights from a full rotation period simulation

NASA Astrophysics Data System (ADS)

He, H.; Jansson, P.-E.; Svensson, M.; Björklund, J.; Tarvainen, L.; Klemedtsson, L.; Kasimir, Å.

2015-12-01

The CoupModel was used to simulate a Norway Spruce forest on fertile drained peat over 60 years, from planting in 1951 until 2011, describing abiotic, biotic and greenhouse gas (GHG) emissions (CO2 and N2O). By calibrating the model against tree ring data we obtained a "reference" model by which we were able to describe the fluxes and controlling factors over the 60 years. We discuss some conceptual issues relevant to improving the model in order to better understand peat soil simulations. However, the present model was able to describe the most important ecosystem dynamics such as the plant biomass development and GHG emissions. The GHG fluxes are composed of two important quantities, the forest carbon (C) uptake, 405 g C m-2 yr-1 and the decomposition of peat soil, 396 g C m-2 yr-1. N2O emissions contribute to the GHG emissions by 0.5 g N m-2 yr-1, corresponding to 56.8 g C m-2 yr-1. The 60-year-old Spruce forest has an accumulated biomass of 164 Mg C ha-1. However, over this period 208 Mg C ha-1 GHG has been added to the atmosphere, which means a net addition of GHG emissions. The main losses are from the peat soil and, indirectly, from forest thinning products, which we assume have a short lifetime. We conclude that after harvest at an age of 80 years, most of the stored biomass carbon is liable to be released, the system having captured C only temporarily and with a cost of disappeared peat, adding CO2 to the atmosphere.

High Temporal Resolution Measurements to Investigate Carbon Dynamics in Subtropical Peat Soils Using Automated Ground Penetrating Radar (GPR) Measurements at the Laboratory Scale

NASA Astrophysics Data System (ADS)

McClellan, M. D.; Wright, W. J.; Job, M. J.; Comas, X.

2015-12-01

Peatlands have the capability to produce and release significant amounts of free phase biogenic gasses (CO2, CH4) into the atmosphere and are thus regarded as key contributors of greenhouse gases into the atmosphere. Many studies throughout the past two decades have investigated gas flux dynamics in peat soils; however a high resolution temporal understanding in the variability of these fluxes (particularly at the matrix scale) is still lacking. This study implements an array of hydrogeophysical methods to investigate the temporal variability in biogenic gas accumulation and release in high resolution for a large 0.073 m3 peat monolith from the Blue Cypress Preserve in central Florida. An autonomous rail system was constructed in order to estimate gas content variability (i.e. build-up and release) within the peat matrix using a series of continuous, uninterrupted ground penetrating radar (GPR) transects along the sample. This system ran non-stop implementing a 0.01 m shot interval using high frequency (1.2 GHz) antennas. GPR measurements were constrained with an array of 6 gas traps fitted with time-lapse cameras in order to capture gas releases at 15 minute intervals. A gas chromatograph was used to determine CH4 and CO2 content of the gas collected in the gas traps. The aim of this study is to investigate the temporal variability in the accumulation and release of biogenic gases in subtropical peat soils at the lab scale at a high resolution. This work has implications for better understanding carbon dynamics in subtropical freshwater peatlands and how climate change may alter such dynamics.

How does whole ecosystem warming of a peatland affect methane production and consumption?

NASA Astrophysics Data System (ADS)

Hopple, A.; Brunik, K.; Keller, J.; Pfeifer-Meister, L.; Woerndle, G.; Zalman, C.; Hanson, P.; Bridgham, S. D.

2017-12-01

Peatlands are among Earth's most important terrestrial ecosystems due to their massive soil carbon (C) stores and significant release of methane (CH4) into the atmosphere. Methane has a sustained-flux global warming potential 45-times greater than carbon dioxide (CO2), and the accuracy of Earth system model projections relies on our mechanistic understanding of peatland CH4 cycling in the context of environmental change. The objective of this study was to determine, under in situ conditions, how heating of the peat profile affects ecosystem-level anaerobic C cycling. We assessed the response of CO2 and CH4 production, as well as the anaerobic oxidation of CH4 (AOM), in a boreal peatland following 13 months of deep peat heating (DPH) and 16 months of subsequent whole-ecosystem warming (surface and deep heating; WEW) as part of the Spruce and Peatland Responses Under Changing Environments (SPRUCE) project in northern Minnesota, USA. The study uses a regression-based experimental design including 5 temperature treatments that warmed the entire 2 m peat profile from 0 to +9 °C above ambient temperature. Soil cores were collected at multiple depths (25-200 cm) from each experimental chamber at the SPRUCE site and anaerobically incubated at in situ temperatures for 1-2 weeks. Methane and CO2 production in surface peat were positively correlated with elevated temperature, but no consistent temperature response was found at depth (75-200 cm) following DPH. However, during WEW, we observed significant increases in both surface and deep peat methanogenesis with increasing temperature. Surface peat had greater CH4 production rates than deeper peat, implying that the increased CH4 emissions observed in the field were largely driven by surface peat warming. The CO2:CH4 ratio was inversely correlated with temperature across all depths following 16 months of WEW, indicating that the entire peat profile is becoming more methanogenic with warming. We also observed AOM throughout the whole peat profile, with the highest rates observed at the surface and initial data suggesting a positive correlation with increasing temperature. While SPRUCE will continue for many years, our initial results suggest that the vast C stores at depth in peatlands are minimally responsive to warming and any response will be driven largely by surface peat.

Are colorimetric assays appropriate for measuring phenol oxidase activity in peat soils?

Treesearch

Magdalena M. Wiedermann; Evan S. Kane; Timothy J. Veverica; Erik A. Lilleskov

2017-01-01

The activity of extracellular phenol oxidases is believed to play a critical role in decomposition processes in peatlands. The water logged, acidic conditions, and recalcitrant litter from the peatland vegetation, lead to exceptionally high phenolics in the peat. In order to quantify the activity of oxidative enzymes involved in the modification and break down of...

Stability of peatland carbon to rising temperatures

Treesearch

R. M. Wilson; A. M. Hopple; M. M. Tfaily; S. D. Sebestyen; C. W. Schadt; L. Pfeifer-Meister; C. Medvedeff; K. J. McFarlane; J. E. Kostka; M. Kolton; R.K. Kolka; L. A. Kluber; J. K. Keller; T. P. Guilderson; N. A. Griffiths; J. P. Chanton; S. D. Bridgham; P. J. Hanson

2016-01-01

Peatlands contain one-third of soil carbon (C), mostly buried in deep, saturated anoxic zones (catotelm). The response of catotelm C to climate forcing is uncertain, because prior experiments have focused on surface warming. We show that deep peat heating of a 2 m-thick peat column results in an exponential increase in CH4 emissions. However,...

Substitution of peat, fertiliser and manure by compost in hobby gardening: user surveys and case studies.

PubMed

Andersen, Jacob K; Christensen, Thomas H; Scheutz, Charlotte

2010-12-01

Four user surveys were performed at recycle centres (RCs) in the Municipalities of Aarhus and Copenhagen, Denmark, to get general information on compost use and to examine the substitution of peat, fertiliser and manure by compost in hobby gardening. The average driving distance between the users' households and the RCs was found to be 4.3 km and the average amount of compost picked up was estimated at 800 kg per compost user per year. The application layer of the compost varied (between 1 and 50 cm) depending on the type of use. The estimated substitution (given as a fraction of the compost users that substitute peat, fertiliser and manure with compost) was 22% for peat, 12% for fertiliser and 7% for manure (41% in total) from the survey in Aarhus (n=74). The estimate from the survey in Copenhagen (n=1832) was 19% for peat, 24% for fertiliser and 15% for manure (58% in total). This is the first time, to the authors' knowledge, that the substitution of peat, fertiliser and manure with compost has been assessed for application in hobby gardening. Six case studies were performed as home visits in addition to the Aarhus surveys. From the user surveys and the case studies it was obvious that the total substitution of peat, fertiliser and manure was not 100%, as is often assumed when assigning environmental credits to compost. It was more likely around 50% and thus there is great potential for improvement. It was indicated that compost was used for a lot of purposes in hobby gardening. Apart from substitution of peat, fertiliser and manure, compost was used to improve soil quality and as a filling material (as a substitute for soil). Benefits from these types of application are, however, difficult to assess and thereby quantify. Copyright © 2010 Elsevier Ltd. All rights reserved.

Lateral carbon fluxes and CO2 outgassing from a tropical peat-draining river

NASA Astrophysics Data System (ADS)

Müller, D.; Warneke, T.; Rixen, T.; Müller, M.; Jamahari, S.; Denis, N.; Mujahid, A.; Notholt, J.

2015-10-01

Tropical peatlands play an important role in the global carbon cycle due to their immense carbon storage capacity. However, pristine peat swamp forests are vanishing due to deforestation and peatland degradation, especially in Southeast Asia. CO2 emissions associated with this land use change might not only come from the peat soil directly but also from peat-draining rivers. So far, though, this has been mere speculation, since there has been no data from undisturbed reference sites. We present the first combined assessment of lateral organic carbon fluxes and CO2 outgassing from an undisturbed tropical peat-draining river. Two sampling campaigns were undertaken on the Maludam River in Sarawak, Malaysia. The river catchment is covered by protected peat swamp forest, offering a unique opportunity to study a peat-draining river in its natural state, without any influence from tributaries with different characteristics. The two campaigns yielded consistent results. Dissolved organic carbon (DOC) concentrations ranged between 3222 and 6218 μmol L-1 and accounted for more than 99 % of the total organic carbon (TOC). Radiocarbon dating revealed that the riverine DOC was of recent origin, suggesting that it derives from the top soil layers and surface runoff. We observed strong oxygen depletion, implying high rates of organic matter decomposition and consequently CO2 production. The measured median pCO2 was 7795 and 8400 μatm during the first and second campaign, respectively. Overall, we found that only 32 ± 19 % of the carbon was exported by CO2 evasion, while the rest was exported by discharge. CO2 outgassing seemed to be moderated by the short water residence time. Since most Southeast Asian peatlands are located at the coast, this is probably an important limiting factor for CO2 outgassing from most of its peat-draining rivers.

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

DTIC Science & Technology

1981-02-01

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

The peats of Costa Rica

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

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

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

Investigation of smoldering combustion propagation of dried peat

NASA Astrophysics Data System (ADS)

Palamba, Pither; Ramadhan, M. L.; Imran, F. A.; Kosasih, E. A.; Nugroho, Y. S.

2017-03-01

Smoldering is a form of combustion characterised by flameless burning of porous materials. Smoldering combustion of porous and organic soil such as peat, is considered as a major contributor to haze problem during wildland fires in Sumatra and Kalimantan, Indonesia. With almost half of tropical peatland worldwide, and vast area that resulted in its rich agricultural diversity, Indonesia possessed many variants of peat throughout the region. Thus, further highlighting the importance of characterizing the thermal properties of different varieties of peats for further analysis. An experimental test method was built to analyse the differences of varying peats from different parts of Indonesia, regarding its smoldering combustion propagation. In this case, peat from Papua and South Sumatera were analysed. A cylindrical wire meshed container of 190 cm3 in volume, was filled with dried peat. The temperature data and mass loss during the smoldering combustion was gathered using thermocouples and a DAQ system. After the experimental apparatus was set, a smoldering combustion of the dried peats was initiated at the top of the container using an electric heater. The results of the experiment showed a smoldering temperature of about 600°C and with a smoldering propagation rate of about 4.50 to 4.75 cm/h for both peat samples.

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

NASA Astrophysics Data System (ADS)

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

2013-12-01

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

Degradation potentials of dissolved organic carbon (DOC) from thawed permafrost peat

PubMed Central

Panneer Selvam, Balathandayuthabani; Lapierre, Jean-François; Guillemette, Francois; Voigt, Carolina; Lamprecht, Richard E.; Biasi, Christina; Christensen, Torben R.; Martikainen, Pertti J.; Berggren, Martin

2017-01-01

Global warming can substantially affect the export of dissolved organic carbon (DOC) from peat-permafrost to aquatic systems. The direct degradability of such peat-derived DOC, however, is poorly constrained because previous permafrost thaw studies have mainly addressed mineral soil catchments or DOC pools that have already been processed in surface waters. We incubated peat cores from a palsa mire to compare an active layer and an experimentally thawed permafrost layer with regard to DOC composition and degradation potentials of pore water DOC. Our results show that DOC from the thawed permafrost layer had high initial degradation potentials compared with DOC from the active layer. In fact, the DOC that showed the highest bio- and photo-degradability, respectively, originated in the thawed permafrost layer. Our study sheds new light on the DOC composition of peat-permafrost directly upon thaw and suggests that past estimates of carbon-dioxide emissions from thawed peat permafrost may be biased as they have overlooked the initial mineralization potential of the exported DOC. PMID:28378792

Effect of Palygorskite Clay, Fertilizers, and Lime on the Degradation of Oil Products in Oligotrophic Peat Soil under Laboratory Experimental Conditions

NASA Astrophysics Data System (ADS)

Tolpeshta, I. I.; Erkenova, M. I.

2018-02-01

The effect of native palygorskite clay and that modified with dodecyltrimethylammonium chloride on the degradation of oil products in an oligotrophic peat soil under complete flooding at the application of lime and mineral fertilizers has been studied under laboratory conditions. It has been shown that the incubation of oil-contaminated soil with unmodified clay and fertilizers at the application of lime under complete flooding with water affects the dynamics of pH and Eh and slows the development of reducing conditions compared to the use of clay without fertilizers. The addition of organoclay under similar conditions favors the formation of potential-determining system with a high redox capacity, which is capable of retaining the potential on a level of 100-200 mV at pH ˜ 7 for two months. It has been found that, under the experimental conditions, unmodified and modified clay, which has no toxic effect on the bacterial complex, does not increase the biodegradation efficiency of oil products in the oligotrophic peat soil compared to the experimental treatments without clay addition. Possible reasons for no positive effect of palygorskite clay on the biodegradation rate of oil products under experimental conditions have been analyzed.

Mapping SOC content and bulk density of a disturbed peatland relict with electromagnetic induction and DEM data

NASA Astrophysics Data System (ADS)

Altdorff, Daniel; Bechtold, Michel; van der Kruk, Jan; Tiemeyer, Bärbel; von Hebel, Christian; Huisman, Johan Alexander

2014-05-01

Peatlands represent a huge storage of soil organic carbon (SOC), and there is considerable interest to assess the total amount of carbon stored in these ecosystems. However, reliable field-scale information about peat properties, particularly SOC content and bulk density (BD) necessary to estimate C stocks, remains difficult to obtain. A potential way to acquire information on these properties and its spatial variation is the non-invasive mapping of easily recordable physical variables that correlate with peat properties, such as bulk electrical conductivity (ECa) measured with electromagnetic induction (EMI). However, ECa depends on a range of soil properties, including BD, soil and water chemistry, and water content, and thus results often show complex and site-specific relationships. Therefore, a reliable prediction of SOC and BD from ECa data is not necessarily given. In this study, we aim to explore the usefulness of Multiple Linear Regression (MLR) models to predict the peat soil properties SOC and BD from multi-offset EMI and high-resolution DEM data. The quality of the MLR models is assessed by cross-validation. We use data from a medium-scale disturbed peat relict (approximately 35ha) in Northern Germany. The potential explanatory variables considered in MLR were: EMI data of six different integral depths (approximately 0.25, 0.5, 0.6, 0.9, 1, and 1.80 m), their vertical heterogeneity, as well as several topographical variables extracted from the DEM. Ground truth information for SOC, BD content and peat layer thickness was obtained from 34 soil cores of 1 m depth. Each core was divided into several 5 to 20 cm thick layers so that integral information of the upper 0.25, 0.5, and 1 m as well as from the total peat layer was obtained. For cross-validation of results, we clustered the 34 soil cores into 4 classes using K-means clustering and selected 8 cores for validation from the clusters with a probability that depended on the size of the cluster. With the remaining 26 samples, we performed a stepwise MLR and generated separate models for each depth and soil property. Preliminary results indicate reliable model predictions for SOC and BD (R² = 0.83- 0.95). The RMSE values of the validation ranged between 3.5 and 7.2 vol. % for SOC and 0.13 and 0.37 g/cm³ for BD for the independent samples. This equates roughly the quality of SOC predictions obtained by field application of vis-NIR (visible-near infrared) presented in literature for a similar peatland setting. However, the EMI approach offers the potential to derive information from deeper depths and allows non-invasive mapping of BD variability, which is not possible with vis-NIR. Therefore, this new approach potentially provides a more useful tool for total carbon stock assessment in peatlands.

Carbon balance of a drained forested bog in southern Finland

NASA Astrophysics Data System (ADS)

Minkkinen, Kari; Penttilä, Timo; Ojanen, Paavo; Lohila, Annalea

2016-04-01

Carbon and greenhouse gas (GHG) dynamics of a drained forested peatland in southern Finland were measured over multiple years, including one with severe drought during growing season. Net ecosystem carbon dioxide exchange (NEE) was measured with an eddy covariance method from a tower above the forest. Soil and forest floor CO2, CH4 and N2O fluxes were measured from the strips and from ditches with closed chambers. Biomasses and litter production were sampled, and soil subsidence was measured by consequtive levelings of the peat surface. The data were used to estimate the ecosystem C pools and annual fluxes of carbon and GHGs of the peatland and to analyse the impact of periodical drought on the carbon fluxes. The drained peatland was a strong sink of carbon dioxide in all studied years. Soil CO2 balance was estimated by subtracting the carbon sink of the growing tree stand from NEE, and it showed that also the soil was a sink of carbon in all studied years. A drought period in one summer significantly decreased the sink through decreased GPP. Drought also decreased the ecosystem respiration, including soil respiration. Decreasing water table thus did not increase, but rather decreased CO2 efflux from the peat soil. The site was a small sink for CH4, even when emissions from ditches were included. N2O emissions were small from all surfaces. Despite of the continuous carbon sink, peat surface subsided slightly (1.4 mm a-1) during the 10-year measurement period, which is interpreted to mean mainly compaction, rather than oxidation of the peat. It is concluded that this drained peatland acts as a continuous soil C sink similarly to an undrained peatland. The reason may be the relatively small water-level drawdown compared to an undrained situation, the consequently rather small changes in plant community structure and the significantly improved tree stand growth and litter production. The consequences of continuing production forestry vs. restoration of the site on the GHG fluxes and climate impact will be discussed.

Permafrost thaw and climate warming may decrease the CO2, carbon, and metal concentration in peat soil waters of the Western Siberia Lowland.

PubMed

Raudina, T V; Loiko, S V; Lim, A; Manasypov, R M; Shirokova, L S; Istigechev, G I; Kuzmina, D M; Kulizhsky, S P; Vorobyev, S N; Pokrovsky, O S

2018-09-01

Soil pore waters are a vital component of the ecosystem as they are efficient tracers of mineral weathering, plant litter leaching, and nutrient uptake by vegetation. In the permafrost environment, maximal hydraulic connectivity and element transport from soils to rivers and lakes occurs via supra-permafrost flow (i.e. water, gases, suspended matter, and solutes migration over the permafrost table). To assess possible consequences of permafrost thaw and climate warming on carbon and Green House gases (GHG) dynamics we used a "substituting space for time" approach in the largest frozen peatland of the world. We sampled stagnant supra-permafrost (active layer) waters in peat columns of western Siberia Lowland (WSL) across substantial gradients of climate (-4.0 to -9.1°C mean annual temperature, 360 to 600mm annual precipitation), active layer thickness (ALT) (>300 to 40cm), and permafrost coverage (sporadic, discontinuous and continuous). We analyzed CO 2 , CH 4 , dissolved carbon, and major and trace elements (TE) in 93 soil pit samples corresponding to several typical micro landscapes constituting the WSL territory (peat mounds, hollows, and permafrost subsidences and depressions). We expected a decrease in intensity of DOC and TE mobilization from soil and vegetation litter to the supra-permafrost water with increasing permafrost coverage, decreasing annual temperature and ALT along a latitudinal transect from 62.3°N to 67.4°N. However, a number of solutes (DOC, CO 2 , alkaline earth metals, Si, trivalent and tetravalent hydrolysates, and micronutrients (Mn, Co, Ni, Cu, V, Mo) exhibited a northward increasing trend with highest concentrations within the continuous permafrost zone. Within the "substituting space for time" climate change scenario and northward shift of the permafrost boundary, our results suggest that CO 2 , DOC, and many major and trace elements will decrease their concentration in soil supra-permafrost waters at the boundary between thaw and frozen layers. As a result, export of DOC and elements from peat soil to lakes and rivers of the WSL (and further to the Arctic Ocean) may decrease. Copyright © 2018 Elsevier B.V. All rights reserved.

Past Peatland Distribution as an Indicator of Hydroclimate and Temperature

NASA Astrophysics Data System (ADS)

Treat, C. C.; Jones, M.; Lacourse, T.; Payne, R.; Peteet, D. M.; Sannel, B.; Stelling, J.; Talbot, J.; Williams, C. J.; Kleinen, T.; Grosse, G.; Yu, Z.; Finkelstein, S. A.; Broothaerts, N.; Dommain, R.; Kuhry, P.; Lähteenoja, O.; Dalton, A.; Notebaert, B.; Swindles, G. T.; Tarnocai, C.; Verstraeten, G.; Xia, Z.; Brovkin, V.

2016-12-01

Peatlands, wetlands with > 30 cm of organic sediment, cover more than 3 x 106 km2 of the earth surface and have been accumulating carbon and sediments throughout the Holocene. The location of peatland formation and accumulation has been dynamic over time, as peat formation in areas like Alaska and the West Siberian Lowlands preceded peat formation in Fennoscandia and Eastern North America due to more favorable climate for peat formation. Using the geographic distribution of peatlands in the past can indicate general climatic conditions, including hydroclimate, given that the underlying geology is well understood. Peatlands form under a variety of climatic conditions and landscape positions but do not persist under arid conditions, instead requiring either humid conditions or cold temperatures. However, peatlands may have existed in the past in areas not currently suitable for peatland formation and persistence, but where peats can be found at depth within the sediment column. Here we map the locations of histic paleosols, relict peat, and buried peats since the Last Glacial Maximum using a compilation of sites from previous studies. We compare these records of past peatland distribution to present-day peatland distribution. We evaluate regional differences in timing of peatland development in these buried peatlands to the development of extant peatlands. Finally, we compare the timing of past peatland extent to the to modeled paleoclimate during the Quaternary. In addition to implications for paleoclimate, these past peatlands are not well accounted for in present-day soil carbon stocks but could be an important component of deep soil carbon pools.

Computer-Controlled Microwave Drying of Potentially Difficult Organic and Inorganic Soils

DTIC Science & Technology

1990-12-01

materials, fly ash, gypsum rich soils, calcite rich soils, organic clay,, peat, and halloysite rich soils. Because specimen sizes too large to be...measurement Field monitoring equipment User’s manual 19. A3STRACT (Continued). materials, organic clay, fly ash, and calcite rich soils are demonstrated...39 Factors Influencing Dehydration ..................................... 42 PART X: STUDIES OF CALCITE

SPRUCE Deep Peat Heating Manipulations: in situ Methods to Characterize the Response of Deep Peat to Warming

NASA Astrophysics Data System (ADS)

Hanson, P. J.; Riggs, J. S.; Barbier, C. N.; Nettles, W. R., IV; Phillips, J. R.; Hook, L.

2014-12-01

Deep soil heating infrastructure was completed in 2014 for a peatland whole-ecosystem warming study that will include air warming starting in 2015 (SPRUCE; http://mnspruce.ornl.gov). In June 2014, we initiated deep soil heating to test the responsiveness of deep peat carbon stocks, microbial communities and biogeochemical cycling processes to heating at 4 warming levels (+2.25, +4.5, +6.75 and +9 °C; 2 replicate plots) compared to fully-constructed control plots (+0 °C; 2 replicate plots). The warming treatments were deployed over eight 113 m2 areas using circular arrays of low-wattage (W) electrical resistance heaters. Perimeter heating was achieved by an exterior circle of 48 100W heaters that apply heat from the surface to a depth of 3 meters. Heating within the study area was accomplished utilizing three zones of 100W "deep only" heaters: an intermediate circle of 12 units, an interior circle of 6 units and one unit placed at the plot center. Heating elements inside the study area apply heat only from -2 to -3 m to keep active heater surfaces away from measured peat volumes. With an average peat depth of 2.5 meters this system was able to warm approximately 113 of the 282 m3 of peat within each target plot. In the absence of the air warming cap, in situ deep peat heating is only effective at sustaining warming in the deep peat layers. Warming levels at depth were achieved over a 25-day (+ 2.25 °C) to a 60-day (+9 °C) period depending on the target treatment temperatures in agreement with a priori energy balance model simulations. Homogeneous temperature distributions between heaters at a given depth interval continued to develop after these targets were reached. Biological and biogeochemical responses to these manipulations are being actively assessed. After one month of transient heating, data for ground-level surface flux of CO2 and CH4 had not shown changes from deep peat heating, but they continue to be tracked and will be summarized in this and related talks.

Effect of granulated wood ash fertilization on N2O emissions in boreal peat forests

NASA Astrophysics Data System (ADS)

Liimatainen, Maarit; Martikainen, Pertti J.; Hytönen, Jyrki; Maljanen, Marja

2016-04-01

Peatlands cover one third of the land surface area in Finland and over half of that are drained for forestry. Natural peatlands are either small sources of nitrous oxide (N2O) or they can also act as a sinks of N2O. When peatlands are drained, oxygen concentration in the peat increases, organic matter decomposition accelerates and N2O emissions may increase significantly, especially in nutrient rich peat soils. Hence drainage and land-use changes can have a big impact on N2O fluxes in peatlands. The annual consumption of wood chips is to be increased to 13.5 M m3 from the present 8.7 M m3 in Finland. This will also increase the amount of wood ash in the power plants. Wood ash contains considerable amounts of mineral nutrients but lacks nitrogen. Therefore, it has been used as a fertilizer in nitrogen rich peatland forests lacking other nutrients. Recycling of ash would also return the nutrients lost during biomass harvesting back to the forests. We studied the effects of granulated wood ash as a fertilizer in peat soils drained for forestry. Ash is nowadays granulated mainly to facilitate its handling and spreading. Granulation also stabilizes the ash decreasing the solubility of most of the nutrients and minimizing harmful effects of ash spread over the vegetation. Granulated wood ash increases soil pH less than loose ash. Drainage of peatland forests increases microbial activity in the soil which is furthermore intensified with the addition of ash promoting organic matter decomposition and possibly affecting N2O emissions. We studied the effect of granulated wood ash on N2O fluxes in three different peat forests in Finland in both field and laboratory experiments. In the field, N2O emissions were not affected by granulated wood ash fertilization but the soil respiration rate increased. However, in the laboratory studies we observed a clear decrease in N2O production due to wood ash addition, although changes in pH values were only minor. We studied what could explain this decrease in N2O production. Despite of the granulation process some nutrients (e.g. K, Na, B, S) still leach quickly from the ash in form of ions, which was observed as an increased electrical conductivity. Granulated ash contains a high concentration of sulfates and we created in the laboratory experiments with the addition of K2SO4 or (NH4)2SO4 similar decrease in N2O production as observed with the addition of granulated wood ash. Our results indicate that quickly leaching ions inhibit nitrification in peat. In the field experiments the same phenomena was not observed, probably due to leaching of the nutrients (ions) deeper into the soil and due to the competition of vegetation which outcompetes microbes for available nutrients. In conclusion, the use of granulated wood ash does not increase N2O emissions in boreal peat forests.

Forests on drained agricultural peatland are potentially large sources of greenhouse gases - insights from a full rotation period simulation

NASA Astrophysics Data System (ADS)

He, Hongxing; Jansson, Per-Erik; Svensson, Magnus; Björklund, Jesper; Tarvainen, Lasse; Klemedtsson, Leif; Kasimir, Åsa

2016-04-01

The CoupModel was used to simulate a Norway Spruce forest on fertile drained peat over 60 years, from planting in 1951 until 2011, describing abiotic, biotic and greenhouse gas (GHG) emissions (CO2 and N2O). By calibrating the model against tree ring derived biomass data and measured 6 year abiotic data we obtained a "reference" model by which we were able to describe the GHG fluxes and controlling factors over the 60 years. The GHG fluxes are composed of two important quantities, the forest carbon (C) uptake, 405 g C m-2 yr-1 and the decomposition of peat soil, 396 g C m-2 yr-1. N2O emissions contribute to the GHG emissions by 0.5 g N m-2 yr-1, corresponding to 56.8 g C m-2 yr-1. The 60-year-old Spruce forest has an accumulated biomass of 164 Mg C ha-1. However, over this period 208 Mg C ha-1 GHG has been added to the atmosphere, which means a net addition of GHG emissions. The main losses are from the peat soil and, indirectly, from forest thinning products, which we assume have a short lifetime. Model sensitivity analysis by changing initial soil C, drainage depth and initial soil C/N ratio also confirms that forests on drained agricultural peatland are a GHG source. We conclude that after harvest at an age of 80 years, most of the stored biomass carbon is liable to be released, the system having captured C only temporarily and with a cost of disappeared peat, adding both CO2 and N2O to the atmosphere.

Evolution of soil and vegetation cover on the bottom of drained thermokarst lake (a case study in the European Northeast of Russia)

NASA Astrophysics Data System (ADS)

Kaverin, Dmitry; Pastukhov, Alexander

2015-04-01

The evolution of soils and landscapes has been studied in a lake bed of former thermokarst lake, which was totally drained in 1979. Melioration of thermokarst lakes was conducted experimentally and locally under Soviet economics program during 1970-s. The aim of the program was to increase in biomass productivity of virgin tundra permafrost-thermokarst sites under agricultural activities. The former thermokarst lake "Opytnoe" located in the Bolshezemelskaya Tundra, Russian European Northeast. The lake bed is covered by peat-mineral sediments, which serves as soil-forming sediments favoring subsequent permafrost aggradation and cryogenic processes as well. Initially, after drainage, swampy meadows had been developed almost all over the lake bed. Further on, succession of landscape went diversely, typical and uncommon tundra landscapes formed. When activated, cryogenic processes favored the formation of peat mounds under dwarf shrub - lichen vegetation (7% of the area). Frost cracks and peat circles affected flat mounds all over the former lake bottom. On drained peat sites, with no active cryogenic processes, specific grass meadows on Cryic Sapric Histosols were developed. Totally, permafrost-affected soils occupy 77% of the area (2011). In some part of the lake bed further development of waterlogging leads to the formation of marshy meadows and willow communities where Gleysols prevail. During last twenty years, permafrost degradation has occurred under tall shrub communities, and it will progress in future. Water erosion processes in the drained lake bottom promoted the formation of local hydrographic network. In the stream floodplain grassy willow-stands formed on Fluvisols (3% of the area). The study has been conducted under Clima-East & RFBR 14-05-31111 projects.

Transport of lead and diesel fuel through a peat soil near Juneau, AK: a pilot study.

Treesearch

Julian Deiss; Carl Byers; Dave Clover; Dave D' Amore; Alan Love; Malcolm A. Menzies; J. Powell; Todd M. Walter

2004-01-01

A set of peat column experiments was used to determine the transport potential of lead (Pb) and diesel range organics (DRO) in palustrine slope wetlands near Juneau, AK. This project is important to southeast Alaskan communities because limited land resources are forcing development of regional wetlands. This study was instigated by concerns that proposed modifications...

Patterns and drivers of fungal community depth stratification in Sphagnum peat

Treesearch

Louis J. Lamit; Karl J. Romanowicz; Lynette R. Potvin; Adam R. Rivers; Kanwar Singh; Jay T. Lennon; Susannah G. Tringe; Evan S. Kane; Erik A. Lilleskov

2017-01-01

Peatlands store an immense pool of soil carbon vulnerable to microbial oxidation due to drought and intentional draining. We used amplicon sequencing and quantitative PCR to (i) examine how fungi are influenced by depth in the peat profile, water table and plant functional group at the onset of a multiyear mesocosm experiment, and (ii) test if fungi are correlated with...

Mineral Soils as Carriers for Rhizobium Inoculants

PubMed Central

Chao, W.-L.; Alexander, Martin

1984-01-01

Mineral soil-based inoculants of Rhizobium meliloti and Rhizobium phaseoli survived better at 4°C than at higher temperatures, but ca. 15% of the cells were viable at 37°C after 27 days. Soil-based inoculants of R. meliloti, R. phaseoli, Rhizobium japonicum, and a cowpea Rhizobium sp. applied to seeds of their host legumes also survived better at low temperatures, but the percent survival of such inoculants was higher than peat-based inoculants at 35°C. Survival of R. phaseoli, R. japonicum, and cowpea rhizobia was not markedly improved when the cells were suspended in sugar solutions before drying them in soil. Nodulation was abundant on Phaseolus vulgaris derived from seeds that had been coated with a soil-based inoculant and stored for 165 days at 25°C. The increase in yield and nitrogen content of Phaseolus angularis grown in the greenhouse was the same with soil-and peat-based inoculants. We suggest that certain mineral soils can be useful and readily available carriers for legume inoculants containing desiccation-resistant Rhizobium strains. PMID:16346460

The influence of organic matter content and media compaction on the dispersal of entomopathogenic nematodes with different foraging strategies.

PubMed

Kapranas, Apostolos; Maher, Abigail M D; Griffin, Christine T

2017-12-01

In laboratory experiments, we investigated how media with varying ratio of peat:sand and two levels of compaction influence dispersal success of entomopathogenic nematode (EPN) species with different foraging strategies: Steinernema carpocapsae (ambusher), Heterorhabditis downesi (cruiser) and Steinernema feltiae (intermediate). Success was measured by the numbers of nematodes moving through a 4 cm column and invading a wax moth larva. We found that both compaction and increasing peat content generally decreased EPN infective juvenile (IJ) success for all three species. Of the three species, H. downesi was the least affected by peat content, and S. carpocapsae was the most adversely influenced by compaction. In addition, sex ratios of the invading IJs of the two Steinernema species were differentially influenced by peat content, and in the case of S. feltiae, sex ratio was also affected by compaction. This indicates that dispersal of male and female IJs is differentially affected by soil parameters and that this differentiation is species-specific. In conclusion, our study shows that organic matter: sand ratio and soil compaction have a marked influence on EPN foraging behaviour with implications for harnessing them as biological pest control agents.

Soil amendments and planting techniques : campsite restoration in the Eagle Cap Wilderness, Oregon

Treesearch

David N. Cole; David R. Spildie

2000-01-01

Results of the first three years of revegetation research on closed wilderness campsites are described. Experimental treatments involved soil scarification, an organic soil amendment (a mix of locally collected organic materials and peat moss and an inoculation of native undisturbed soil), an organic matter and composted sewage sludge treatment and surface application...

The effects of engineering fabric in street pavement on low bearing capacity soil in New Orleans : executive summary.

DOT National Transportation Integrated Search

1985-07-01

Subsurface soil in the New Orleans area is generally composed of peat and clay. The low bearing capacity of the soft natural soil has caused early deterioration of asphaltic concrete pavements which typically fail prior to carrying their designed loa...

Enhanced greenhouse gas emissions from the Arctic with experimental warming

NASA Astrophysics Data System (ADS)

Voigt, Carolina; Lamprecht, Richard E.; Marushchak, Maija E.; Lind, Saara E.; Novakovskiy, Alexander; Aurela, Mika; Martikainen, Pertti J.; Biasi, Christina

2017-04-01

Temperatures in the Arctic are projected to increase more rapidly than in lower latitudes. With temperature being a key factor for regulating biogeochemical processes in ecosystems, even a subtle temperature increase might promote the release of greenhouse gases (GHGs) to the atmosphere. Usually, carbon dioxide (CO2) and methane (CH4) are the GHGs dominating the climatic impact of tundra. However, bare, patterned ground features in the Arctic have recently been identified as hot spots for nitrous oxide (N2O). N2O is a potent greenhouse gas, which is almost 300 times more effective in its global warming potential than CO2; but studies on arctic N2O fluxes are rare. In this study we examined the impact of temperature increase on the seasonal GHG balance of all three important GHGs (CO2, CH4 and N2O) from three tundra surface types (vegetated peat soils, unvegetated peat soils, upland mineral soils) in the Russian Arctic (67˚ 03' N 62˚ 55' E), during the course of two growing seasons. We deployed open-top chambers (OTCs), inducing air and soil surface warming, thus mimicking predicted warming scenarios. We combined detailed CO2, CH4 and N2O flux studies with concentration measurements of these gases within the soil profile down to the active layer-permafrost interface, and complemented these GHG measurements with detailed soil nutrient (nitrate and ammonium) and dissolved organic carbon (DOC) measurements in the soil pore water profile. In our study, gentle air warming (˜1.0 ˚ C) increased the seasonal GHG release of all dominant surface types: the GHG budget of vegetated peat and mineral soils, which together cover more than 80 % of the land area in our study region, shifted from a sink to a source of -300 to 144 g CO2-eq m-2 and from -198 to 105 g CO2-eq m-2, respectively. While the positive warming response was governed by CO2, we provide here the first in situ evidence that warming increases arctic N2O emissions: Warming did not only enhance N2O emissions from the known arctic N2O hot spots (bare peat soils; maximum seasonal release with warming: 87 mg N2O m-2), but also from the vegetated peat surfaces, not emitting N2O under present climate. These surfaces showed signs of a hampered plant growth, leading to reduced soil N uptake with warming, indicating that plants are regulating arctic N2O emissions. The warming treatment was limited to temperature of air and upper soil surface, and did not alter thaw depth. Nonetheless, we observed a clear increase of all three GHGs deep in the soil profile, and attribute this to downward leaching of labile organic substances from the surface soil and/or plants, fueling microbial activity at depth. Our study thus highlights the tight interlinkage between the surface soil, vegetation, and deeper soil layers, which could lead to losses of all three GHGs, including N2O, with subtle temperature increase. We therefore emphasize that indirect effects caused by warming, such as leaching processes, as well as arctic N2O emissions, need to be taken into account when attempting to project feedbacks between the arctic and the global climate system.

Utilization of forest slash to sequester carbon in loblolly pine plantations in the lower coastal plain

Treesearch

F. Sanchez; E.A. Carter; W. Edwards

2002-01-01

Soil-organic matter (SOM) is a complex array of components including soil fauna and flora at different stages of decomposition (Berg et al., 1982). Its concentration in soils can vary from 0.5% in mineral soils to almost 100% in peat soils (Brady, 1974). Organic matter (OM) in the surface mineral soil is considered a major determinant of forest ecosystem productivity...

Influence of soil organic matter composition on the partition of organic compounds

USGS Publications Warehouse

Rutherford, D.W.; Chiou, C.T.; Klle, D.E.

1992-01-01

The sorption at room temperature of benzene and carbon tetrachloride from water on three high-organic-content soils (muck, peat, and extracted peat) and on cellulose was determined in order to evaluate the effect of sorbent polarity on the solute partition coefficients. The isotherms are highly linear for both solutes on all the organic matter samples, which is consistent with a partition model. For both solutes, the extracted peat shows the greatest sorption capacity while the cellulose shows the lowest capacity; the difference correlates with the polar-to-nonpolar group ratio [(O + N)/C] of the sorbent samples. The relative increase of solute partition coefficient (Kom) with a decrease of sample polar content is similar for both solutes, and the limiting sorption capacity on a given organic matter sample is comparable between the solutes. This observation suggests that one can estimate the polarity effect of a sample of soil organic matter (SOM) on Kom of various nonpolar solutes by determining the partition coefficient of single nonpolar solute when compositional analysis of the SOM is not available. The observed dependence of Kom on sample polarity is used to account for the variation of Kom values of individual compounds on different soils that results from change in the polar group content of SOM. On the assumption that the carbon content of SOM in "ordinary soils" is 53-63%, the calculated variation of Kom is a factor of ???3. This value is in agreement with the limit of variation of most Kom data with soils of relatively high SOM contents.

Effects of rice husks and their chars from hydrothermal carbonization on the germination rate and root length of Lepidium sativum

NASA Astrophysics Data System (ADS)

Kern, Jürgen; Mukhina, Irina; Dicke, Christiane; Lanza, Giacomo; Kalderis, Dimitrios

2015-04-01

Currently, char substrates gain a lot of interest, since they are being discussed as a component in growing media, which may become one option for the replacement of peat. Among different thermal conversion processes of biomass hydrothermal carbonization (HTC) has been found to produce chars with similar acidic pH values like peat. The question however is, if these hydrochars, which may contain toxic phenolic compounds are suitable to be introduced as a new substitute for peat in horticulture. In this study rice husk were hydrothermally carbonized at 200° C for 6 hours, yielding in hydrochars containing organic contaminants such as phenols and furfurals, which may affect plants and soil organisms. We investigated potential toxic effects on the germination rate and the root length of cress salad (Lepidium sativum) in four fractions: i) soil control, ii) raw rice husk + soil, iii) unwashed rice char + soil and iv) acetone/water washed rice char + soil. It could be shown that phenols and furfurals, which were removed from the hydrochar after washing by 80 to 96% did not affect the germination rate and the root length of the cress plants. The lowest germination rate and root length were found in the soil control, the highest in the non-washed hydrochar treatment, indicating a fertilization effect and growth stimulation of cress salad by hydrochar. If this result can be confirmed for other target and non-target organisms in future studies, a new strategy for the production of growing media may be developed.

Artificial soils from alluvial tin mining wastes in Malaysia--a study of soil chemistry following experimental treatments and the impact of mycorrhizal treatment on growth and foliar chemistry.

PubMed

Tompkins, David S; Bakar, Baki B; Hill, Steve J

2012-01-01

For decades Malaysia was the world's largest producer of Sn, but now the vast open cast mining operations have left a legacy of some 100,000 ha of what is effectively wasteland, covered with a mosaic of tailings and lagoons. Few plants naturally recolonise these areas. The demand for such land for both urban expansion and agricultural use has presented an urgent need for better characterisation. This study reports on the formation of artificial soils from alluvial Sn mining waste with a focus on the effects of experimental treatments on soil chemistry. Soil organic matter, clay, and pH were manipulated in a controlled environment. Adding both clay tailings and peat enhanced the cation exchange capacity of sand tailings but also reduced the pH. The addition of peat reduced the extractable levels of some elements but increased the availability of Ca and Mg, thus proving beneficial. The use of clay tailings increased the levels of macro and micronutrients but also released Al, As, La, Pb and U. Additionally, the effects of soil mix and mycorrhizal treatments on growth and foliar chemistry were studied. Two plant species were selected: Panicum milicaeum and Pueraria phaseoloides. Different growth patterns were observed with respect to the additions of peat and clay. The results for mycorrhizal treatment (live inoculum or sterile carrier medium) are more complex, but both resulted in improved growth. The use of mycorrhizal fungi could greatly enhance rehabilitation efforts on sand tailings.

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

USGS Publications Warehouse

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

2007-01-01

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

[Distribution of soil organic carbon storage and carbon density in Gahai Wetland ecosystem].

PubMed

Ma, Wei-Wei; Wang, Hui; Huang, Rong; Li, Jun-Zhen; Li, De-Yu

2014-03-01

The profile distribution and accumulation characteristics of organic carbon of four typical marshes (herbaceous peat, marsh wetland, mountain wetland, subalpine meadow) were studied in Gahai Wetlands of Gannan in July 2011. The results showed that the soil bulk densities of the four typical marshes ranged from 0.22 to 1.29 g x cm(-3). The content of soil organic carbon in the herbaceous peat was higher than in other types, with its average content of organic carbon (286. 80 g x kg(-1)) being about 2.91, 4.99, 7.31 times as much as that of the marsh wetland, mountain wetland and subalpine meadow, respectively. The average organic carbon densities were in order of herbaceous peat > subalpine meadow > marsh wetland > mountain wetland, with the highest in the 0-10 cm layer. The change of organic carbon density along the soil profile was basically in accordance with the organic carbon content in the four typical marshes, but fluctuated with soil depth. There were obviously two carbon storage layers (0-10 and 20-40 cm, respectively) in the four typical marshes. The amounts of organic carbon stored in the 0-60 cm layer of the four typical marshes were 369.46, 278.83, 276.16, 292.23 t x hm(-2), respectively. The total amount of organic carbon stored in the 0-60 cm of the four typical marshes was about 9.50 x 10(6) t.

Quantifying soil carbon loss and uncertainty from a peatland wildfire using multi-temporal LiDAR

USGS Publications Warehouse

Reddy, Ashwan D.; Hawbaker, Todd J.; Wurster, F.; Zhu, Zhiliang; Ward, S.; Newcomb, Doug; Murray, R.

2015-01-01

Peatlands are a major reservoir of global soil carbon, yet account for just 3% of global land cover. Human impacts like draining can hinder the ability of peatlands to sequester carbon and expose their soils to fire under dry conditions. Estimating soil carbon loss from peat fires can be challenging due to uncertainty about pre-fire surface elevations. This study uses multi-temporal LiDAR to obtain pre- and post-fire elevations and estimate soil carbon loss caused by the 2011 Lateral West fire in the Great Dismal Swamp National Wildlife Refuge, VA, USA. We also determine how LiDAR elevation error affects uncertainty in our carbon loss estimate by randomly perturbing the LiDAR point elevations and recalculating elevation change and carbon loss, iterating this process 1000 times. We calculated a total loss using LiDAR of 1.10 Tg C across the 25 km2 burned area. The fire burned an average of 47 cm deep, equivalent to 44 kg C/m2, a value larger than the 1997 Indonesian peat fires (29 kg C/m2). Carbon loss via the First-Order Fire Effects Model (FOFEM) was estimated to be 0.06 Tg C. Propagating the LiDAR elevation error to the carbon loss estimates, we calculated a standard deviation of 0.00009 Tg C, equivalent to 0.008% of total carbon loss. We conclude that LiDAR elevation error is not a significant contributor to uncertainty in soil carbon loss under severe fire conditions with substantial peat consumption. However, uncertainties may be more substantial when soil elevation loss is of a similar or smaller magnitude than the reported LiDAR error.

Investigating carbon flux variability in subtropical peat soils of the Everglades using hydrogeophysical methods

NASA Astrophysics Data System (ADS)

Comas, Xavier; Wright, William

2014-08-01

The spatial and temporal variability in accumulation and release of greenhouse gases (mainly methane and carbon dioxide) to the atmosphere from peat soils remains very uncertain. The use of near-surface geophysical methods such as ground penetrating radar (GPR) has proven useful during the last decade to expand scales of measurement as related to in situ gas distribution and dynamics beyond traditional methods (i.e., gas chambers). However, this approach has focused exclusively on boreal peatlands, while no studies in subtropical systems like the Everglades using these techniques exist. In this paper GPR is combined with gas traps, time-lapse cameras, gas chromatography, and surface deformation measurements to explore biogenic gas dynamics (mainly gas buildup and release) in two locations in the Everglades. Similar to previous studies in northern peatlands, our data in the Everglades show a statistically significant correlation between the following: (1) GPR-estimated gas content and gas fluxes, (2) GPR-estimated gas content and surface deformation, and (3) atmospheric pressure and both GPR-estimated gas content and gas flux. From these results several gas-releasing events ranging between 33.8 and 718.8 mg CH4 m-2 d-1 were detected as identified by the following: (1) decreases in GPR-estimated gas content within the peat matrix, (2) increases in gas fluxes captured by gas traps and time-lapse cameras, and (3) decreases in surface deformation. Furthermore, gas-releasing events corresponded to periods of high atmospheric pressure. Changes in gas accumulation and release were attributed to differences in seasonality and peat soil type between sites. These results suggest that biogenic gas releases in the Everglades are spatially and temporarily variable. For example, flux events measured at hourly scales were up to threefold larger when compared to daily fluxes, therefore suggesting that flux measurements decline when averaged over longer time spans. This research therefore questions what the appropriate spatial and temporal scale of measurement is necessary to properly capture the dynamics of biogenic gas release in subtropical peat soils.

Controls on the methane released through ebullition affected by permafrost degradation

Treesearch

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

2014-01-01

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

Reservoir-flooded river mouth areas as sediment traps revealing erosion from peat mining areas - Jukajoki case study in eastern Finland

NASA Astrophysics Data System (ADS)

Tahvanainen, Teemu; Meriläinen, Henna-Kaisa; Haraguchi, Akira; Simola, Heikki

2016-04-01

Many types of soil-disturbing land use have caused excess sedimentation in Finnish lakes. Identification and quantification of catchment sources of sediment material is crucial in cases where demands for remediation measures are considered. We studied recent (50 yr) sediments of four small rivers, all draining to a reservoir impounded in 1971. Catchments of two of the rivers had had peat mining activities from early 1980s until recently, exposing large areas of peat surfaces to erosion. The water level of the reservoir had risen to the river mouth areas of all rivers, while in each case, the river mouth areas still form riverine narrows separable from the main reservoir, hence collecting sedimentation from their own catchments. The original soils under the reservoir water level could readily be observed in core samples, providing a dated horizon under recent sediments. In addition, we used 137Cs-stratigraphies for dating of samples from original river bed locations. As expected, recent sediments of rivers with peat mining influence differed from others e.g. by high organic content and C:N ratios. Stable isotopes 13C and 15N both correlated with C:N (r = 0.799 and r = -0.717, respectively) and they also differentiated the peat-mining influenced samples from other river sediments. Principal components of the physical-chemical variables revealed clearer distinction than any variables separately. Light-microscopy revealed abundance of leafs of Sphagnum mosses in peat-mining influenced river sediments that were nearly absent from other rivers. Spores of Sphagnum were, however, abundant in all river sediments indicating their predominantly airborne origin. We find that combination of several physical-chemical characters rather than any single variable and microscopy of plant remains can result in reliable recognition of peatland-origin of sediment material when non-impacted sites are available for comparison. Dating of disturbed recent sediments is challenging. River-mouth areas with reservoir history can be particularly useful as the terrestrial soil strata provides a dated horizon under recent sediments.

ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO2, water, and energy fluxes on daily to annual scales

NASA Astrophysics Data System (ADS)

Qiu, Chunjing; Zhu, Dan; Ciais, Philippe; Guenet, Bertrand; Krinner, Gerhard; Peng, Shushi; Aurela, Mika; Bernhofer, Christian; Brümmer, Christian; Bret-Harte, Syndonia; Chu, Housen; Chen, Jiquan; Desai, Ankur R.; Dušek, Jiří; Euskirchen, Eugénie S.; Fortuniak, Krzysztof; Flanagan, Lawrence B.; Friborg, Thomas; Grygoruk, Mateusz; Gogo, Sébastien; Grünwald, Thomas; Hansen, Birger U.; Holl, David; Humphreys, Elyn; Hurkuck, Miriam; Kiely, Gerard; Klatt, Janina; Kutzbach, Lars; Largeron, Chloé; Laggoun-Défarge, Fatima; Lund, Magnus; Lafleur, Peter M.; Li, Xuefei; Mammarella, Ivan; Merbold, Lutz; Nilsson, Mats B.; Olejnik, Janusz; Ottosson-Löfvenius, Mikaell; Oechel, Walter; Parmentier, Frans-Jan W.; Peichl, Matthias; Pirk, Norbert; Peltola, Olli; Pawlak, Włodzimierz; Rasse, Daniel; Rinne, Janne; Shaver, Gaius; Schmid, Hans Peter; Sottocornola, Matteo; Steinbrecher, Rainer; Sachs, Torsten; Urbaniak, Marek; Zona, Donatella; Ziemblinska, Klaudia

2018-02-01

Peatlands store substantial amounts of carbon and are vulnerable to climate change. We present a modified version of the Organising Carbon and Hydrology In Dynamic Ecosystems (ORCHIDEE) land surface model for simulating the hydrology, surface energy, and CO2 fluxes of peatlands on daily to annual timescales. The model includes a separate soil tile in each 0.5° grid cell, defined from a global peatland map and identified with peat-specific soil hydraulic properties. Runoff from non-peat vegetation within a grid cell containing a fraction of peat is routed to this peat soil tile, which maintains shallow water tables. The water table position separates oxic from anoxic decomposition. The model was evaluated against eddy-covariance (EC) observations from 30 northern peatland sites, with the maximum rate of carboxylation (Vcmax) being optimized at each site. Regarding short-term day-to-day variations, the model performance was good for gross primary production (GPP) (r2 = 0.76; Nash-Sutcliffe modeling efficiency, MEF = 0.76) and ecosystem respiration (ER, r2 = 0.78, MEF = 0.75), with lesser accuracy for latent heat fluxes (LE, r2 = 0.42, MEF = 0.14) and and net ecosystem CO2 exchange (NEE, r2 = 0.38, MEF = 0.26). Seasonal variations in GPP, ER, NEE, and energy fluxes on monthly scales showed moderate to high r2 values (0.57-0.86). For spatial across-site gradients of annual mean GPP, ER, NEE, and LE, r2 values of 0.93, 0.89, 0.27, and 0.71 were achieved, respectively. Water table (WT) variation was not well predicted (r2 < 0.1), likely due to the uncertain water input to the peat from surrounding areas. However, the poor performance of WT simulation did not greatly affect predictions of ER and NEE. We found a significant relationship between optimized Vcmax and latitude (temperature), which better reflects the spatial gradients of annual NEE than using an average Vcmax value.

Monitoring the effects of manure policy in the Peat region, Netherlands

NASA Astrophysics Data System (ADS)

Hooijboer, Arno; Buis, Eke; Fraters, Dico; Boumans, Leo; Lukacs, Saskia; Vrijhoef, Astrid

2014-05-01

Total N concentrations in farm ditches in the Peat region of the Netherlands are on the average twice as high as the Good Ecological Potential value of the Water Framework Directive. Since ditches are connected to regional surface water, they may contribute to eutrophication. The minerals policy aims to improve the water quality. In the Netherlands, the effectiveness of the minerals policy on water quality is evaluated with data from the National Minerals Policy Monitoring Programme (LMM). This regards farm data on the quality of water leaching from the root zone and on farm practices. The soil balance nitrogen surpluses decreased between 1996 and 2003 on dairy farms in the Peat region. However, no effect on root zone leaching was found. This study aims to show how monitoring in the Peat region can be improved in order to link water quality to agricultural practice. Contrary to the other Dutch regions, nitrate concentrations in root zone leaching on farms in the Peat region are often very low (90% of the farms below 25 mg/l) due to the reduction of nitrate (denitrification). The main nitrogen (N) components in the peat region waters are ammonium and organic N. Total N is therefore a better measure for N concentrations in the Peat region. The ammonium concentration in groundwater in Dutch peat soils increases with depth. It is assumed that the deeper ammonia-rich water is older and relates to anaerobic peat decomposition instead of agricultural practice. Recent infiltrated low-ammonium water, lies like a thin freshwater lens on the older water. In the Peat region, root zone leaching is monitored by taking samples from the upper meter of groundwater. Unintended, often both lens water and older water are sampled and this distorts the relation between agricultural practice and water quality. In the Peat region, the N surplus is transported with the precipitation surplus to ditches. The relation between the N surplus and the total N in ditch water is therefore better than between N surplus and total N in root zone leaching. The precipitation surplus flows to ditches directly or via open field drains. However, the ditches may be fed partly with older water (seepage of groundwater). In the open field drain only recent water will occur. We expect that monitoring the water quality of the open field drains may even better reflect changes in agricultural practices. These data may also improve the understanding of contribution of agricultural nitrogen and natural nitrogen, necessary to develop measures to decrease the total-N concentration in ditch water.

Profile distribution of polycyclic aromatic hydrocarbons in soils of drained peatlands after wildfires (Moscow region, Russia)

NASA Astrophysics Data System (ADS)

Tsibart, Anna; Gennadiev, Alexander; Koshovskii, Timur; Kovach, Roman

2014-05-01

Polycyclic aromatic compounds (PAHs) are formed in different natural and anthropogenic processes and could be found in many landscape components. These compounds are carcinogenic and belong to the group of persistent organic pollutants. The anthropogenic sources of PAHs are well-studied, but insufficient data are available on the hightemperature production of PAHs in natural processes. For example, natural fires are frequently related to the PAHs sources in landscapes, but very little factual data are on this topic. The soils of drained peatlands affected by catastrophic wildfires of 2010 and 2002 were studied in the Eastern part of Moscow Region (Russia). A total of 14 profiles of histosols and histic podsols were investigated. These series included soils of plots subjected to fires of different intensities and age, as well as soils of the background plots. Soil samples were taken from genetic horizons and from every 10 cm. The samples were analyzed for the contents of 14 prevailing individual compounds: fluorene, naphthalene, phenanthrene, chrysene, pyrene, anthracene, tetraphene, benz[a]pyrene, benzo[ghi]perylene, benzo[e]pyrene, coronene, dibenztiophene, triphenilene, benz(k)fluorantene. Morfological properties of soils after wildfires on drained peatlands were changed dramatically, the horizons of ash and char instead of organic layers were formed. These new horizons differ in the capability of PAHs accumulation. The char horizons have the highest concentrations of PAHs - up to 300 ng/g because of incomplete burning of organic matter in this sites, and the ash horizons, where the complete burning occured, contain only 10 ng/g PAHs. The highest concentrations of PAHs in soil profiles were detected after recent fires, and in cases of thick peat layers. After the combustion of peat chrysene, benz[a]pyrene, benz[e]pyrene, benzo[ghi]perylene, benz(k)fluorantene and tetraphene accumulated in soils. This is mainly the group of 4-6-nuclear compounds. The formation of high-molecular weight compounds is possible during smoldering process under a low oxygen supply. The oxygen deficit acts as a factor of the organic fragments recombination and PAHs production; therefore, relatively large amounts of PAHs are formed in peat fires. Moreover the peat fires occur directly in the soil layer; therefore, larger amounts of the resulting PAHs remain in the soils of the fire sites. The migration of low-molecular weight compounds occures in histic podsols, in histosols PAHs accumalate only in upper organic horizons. The research was conducted with the support of Russian Geographical Society.

Factors affecting sustained smouldering in organic soils from pocasin and pond pine woodland wetlands

Treesearch

James Reardon; Roger Hungerford; Kevin Ryan

2007-01-01

The smouldering combustion of peat and muck soil plays an important role in the creation and maintenance of wetland communities. This experimental study was conducted to improve our understanding of how moisture and mineral content constrain smouldering in organic soil. Laboratory burning was conducted with root mat and muck soil samples from pocosin and pond pine...

Seasonally frozen layer in natural and drained peatlands at the South of West Siberia, Russia

NASA Astrophysics Data System (ADS)

Dyukarev, Egor; Kiselev, Maxim; Voropay, Nadezhda; Preis, Yulia

2017-04-01

The temperature regime of soils in natural and drained peatlands at Bakchar bog located in the South Taiga zone of West Siberia is studied. Soil temperature for depths up to 320 cm was registered using autonomous temperature profile recorder during the period from August 2010 to September 2016. Maximal and minimal temperatures were registered at surface in July and February, consequently. Extreme soil temperatures at 320 cm depth shifts to December (maximum) and July (minimum) reducing absolute values. Annual peat soil temperature amplitude decrease with depth from 21,8 °C on surface to 1,1 °C at 320 cm. The analysis of daily, month and annual mean data of temperature in peat soil has shown that seasonally frozen layer was registered up to 20-60 cm depth. The duration of seasonally freeze layer existence varies from 130 to 180 days. Drained peatlands with the lowest water table have highest freeze depth. Soil at water-logged sedge-sphagnum fen in winter is warmer than soil in ryam ecosystem and mineral soil at upland. Maximal freezing depth in peatlands is up to 3 times lower than at drain areas.

Degradation of Malaysian peatlands decreases levels of phenolics in soil and in leaves of Macaranga pruinosa

NASA Astrophysics Data System (ADS)

Yule, Catherine; Lim, Yau; Lim, Tse

2016-04-01

Indo-Malaysian tropical peat swamp forests (PSF) sequester enormous stores of carbon in the form of phenolic compounds, particularly lignin as well as tannins. These phenolic compounds are crucial for ecosystem functioning in PSF through their inter-related roles in peat formation and plant defenses. Disturbance of PSF causes destruction of the peat substrate, but the specific impact of disturbance on phenolic compounds in peat and its associated vegetation has not previously been examined. A scale was developed to score peatland degradation based on the three major human impacts that affect tropical PSF - logging, drainage and fire. The objectives of this study were to compare the amount of phenolic compounds in Macaranga pruinosa, a common PSF tree, and in the peat substrate along a gradient of peatland degradation from pristine peat swamp forest to cleared, drained and burnt peatlands. We examined phenolic compounds in M. pruinosa and in peat and found that levels of total phenolic compounds and total tannins decrease in the leaves of M.pruinosa and also in the surface peat layers with an increase in peatland degradation. We conclude that waterlogged conditions preserve the concentration of phenolic compounds in peat, and that even PSF that has been previously logged but which has recovered a full canopy cover will have high levels of total phenolic content (TPC) in peat. High levels of TPC in peat and in the flora are vital for the inhibition of decomposition of organic matter and this is crucial for the accretion of peat and the sequestration of carbon. Thus regional PSF flourish despite the phenolic rich, toxic, waterlogged, nutrient poor, conditions, and reversal of such conditions is a sign of degradation.

Comparing geophysical measurements to theoretical estimates for soil mixtures at low pressures

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

Wildenschild, D; Berge, P A; Berryman, K G

1999-01-15

The authors obtained good estimates of measured velocities of sand-peat samples at low pressures by using a theoretical method, the self-consistent theory of Berryman (1980), using sand and porous peat to represent the microstructure of the mixture. They were unable to obtain useful estimates with several other theoretical approaches, because the properties of the quartz, air and peat components of the samples vary over several orders of magnitude. Methods that are useful for consolidated rock cannot be applied directly to unconsolidated materials. Instead, careful consideration of microstructure is necessary to adapt the methods successfully. Future work includes comparison of themore » measured velocity values to additional theoretical estimates, investigation of Vp/Vs ratios and wave amplitudes, as well as modeling of dry and saturated sand-clay mixtures (e.g., Bonner et al., 1997, 1998). The results suggest that field data can be interpreted by comparing laboratory measurements of soil velocities to theoretical estimates of velocities in order to establish a systematic method for predicting velocities for a full range of sand-organic material mixtures at various pressures. Once the theoretical relationship is obtained, it can be used to estimate the soil composition at various depths from field measurements of seismic velocities. Additional refining of the method for relating velocities to soil characteristics is useful for development inversion algorithms.« less

The Dependence of Peat Soil Hydraulic Conductivity on Dominant Vegetation Type in Mountain Fens

NASA Astrophysics Data System (ADS)

Crockett, A. C.; Ronayne, M. J.; Cooper, D. J.

2014-12-01

The peat soil within fen wetlands provides water storage that can substantially influence the hydrology of mountain watersheds. In this study, we investigated the relationship between hydraulic conductivity and vegetation type for fens occurring in Rocky Mountain National Park (RMNP), Colorado, USA. Vegetation in RMNP fens can be dominated by woody plants and shrubs, such as willows; by mosses; or by herbaceous plants such as sedges. Fens dominated by each vegetation type were selected for study. Six fens were investigated, all of which are in the Colorado River watershed on the west side of RMNP. For each site, soil hydraulic conductivity was measured at multiple locations using a single-ring infiltrometer. As a result of the shallow water table in these fens (the water table was always within 10 cm of the surface), horizontal hydraulic gradients were produced during the field tests. The measured infiltration rates were analyzed using the numerical model HYDRUS. In order to determine the hydraulic conductivity, a parameter estimation problem was solved using HYDRUS as the forward simulator. Horizontal flow was explicitly accounted for in the model. This approach produced more accurate estimates of hydraulic conductivity than would be obtained using an analytical solution that assumes strictly vertical flow. Significant differences in hydraulic properties between fens appear to result at least in part from the effects of different dominant vegetation types on peat soil formation.

Uplifting of palsa peatlands by permafrost identified by stable isotope depth profiles

NASA Astrophysics Data System (ADS)

Krüger, Jan Paul; Conen, Franz; Leifeld, Jens; Alewell, Christine

2015-04-01

Natural abundances of stable isotopes are a widespread tool to investigate biogeochemical processes in soils. Palsas are peatlands with an ice core and are common in the discontinuous permafrost region. Elevated parts of palsa peatlands, called hummocks, were uplifted by permafrost out of the influence of groundwater. Here we used the combination of δ15N values and C/N ratio along depth profiles to identify perturbation of these soils. In the years 2009 and 2012 we took in total 14 peat cores from hummocks in two palsa peatlands near Abisko, northern Sweden. Peat samples were analysed in 2 to 4 cm layers for stable isotope ratios and concentrations of C and N. The uplifting of the hummocks by permafrost could be detected by stable isotope depth patterns with the highest δ15N value at permafrost onset, a so-called turning point. Regression analyses indicated in 11 of 14 peat cores increasing δ15N values above and decreasing values below the turning point. This is in accordance with the depth patterns of δ13C values and C/N ratios in these palsa peatlands. Onset of permafrost aggradation identified by the highest δ15N value in the profile and calculated from peat accumulation rates show ages ranging from 80 to 545 years and indicate a mean (±SD) peat age at the turning points of 242 (±66) years for Stordalen and 365 (±53) years for Storflaket peatland. The mean peat ages at turning points are within the period of the Little Ice Age. Furthermore, we tested if the disturbance, in this case the uplifting of the peat material, can be displayed in the relation of δ15N and C/N ratio following the concept of Conen et al. (2013). In unperturbed sites soil δ15N values cover a relatively narrow range at any particular C/N ratio. Changes in N cycling, i.e. N loss or gain, results in the loss or gain of 15N depleted forms. This leads to larger or smaller δ15N values than usual at the observed C/N ratio. All, except one, turning point show a perturbation in the depth profile, with most of the adjacent sampling points also indicating perturbation. This perturbation shows the changes in N cycling, in this case N loss, from these depths due to permafrost aggradation. Deeper parts of some profiles at Stordalen peatland indicate with the same approach an N gain, maybe due to lateral N input to these nutrient poor ecosystems. Most of the uppermost samples in the δ15N depth profiles show no perturbation, potentially due to the adaptation of these soils to the new conditions. Both stable isotope (δ15N and δ13C) depth profiles are suitable to detect palsa uplifting by permafrost. The perturbation of the peat by uplifting as well as the potential nutrient input can be detected by δ15N when related to the C/N ratio. Conen, F., Yakutin, M. V., Carle, N., and Alewell, C. (2013): δ15N natural abundance may directly disclose perturbed soil when related to C:N ratio. Rapid Commun. Mass Spectrom. 27: 1101-1104.

Modeling the Impact of Forest and Peat Fires on Carbon-Isotopic Compositions of Cretaceous Atmosphere and Vegetation

NASA Astrophysics Data System (ADS)

Finkelstein, D. B.; Pratt, L. M.

2004-12-01

Prevalence of wildfires or peat fires associated with seasonally dry conditions in the Cretaceous is supported by recent studies documenting the widespread presence of pyrolytic polycyclic aromatic hydrocarbons and fusinite. Potential roles of CO2 emissions from fire have been overlooked in many discussions of Cretaceous carbon-isotope excursions (excluding K-P boundary discussions). Enhanced atmospheric CO2 levels could increase fire frequency through elevated lightning activity. When biomass or peat is combusted, emissions of CO2 are more negative than atmospheric CO2. Five reservoirs (atmosphere, vegetation, soil, and shallow and deep oceans), and five fluxes (productivity, respiration, litter fall, atmosphere-ocean exchange, and surface-deep ocean exchange) were modeled as a closed system. The size of the Cretaceous peat reservoir was estimated by compilation of published early Cretaceous coal resources. Initial pCO2 was assumed to be 2x pre-industrial atmospheric levels (P.A.L.). Critical variables in the model are burning efficiency and post-fire growth rates. Assuming 1% of standing terrestrial biomass is consumed by wildfires each year for ten years (without combustion of peat), an increase of atmospheric CO2 (from 2.0 to 2.2x P.A.L.) and a negative carbon isotope excursion (-1.2 ‰ ) are recorded by both atmosphere and new growth. Net primary productivity linked to the residence time of the vegetation and soil reservoirs results in a negative isotope shift followed by a broad positive isotope excursion. Decreasing the rate of re-growth dampens this trailing positive shift and increases the duration of the excursion. Post-fire pCO2 and new growth returned to initial values after 72 years. Both negative and positive isotope excursions are recorded in the model in surface ocean waters. Exchange of CO2 with the surface- and deep-ocean dampens the isotopic shift of the atmosphere. Excursions are first recorded in the atmosphere (and new growth), followed by the ocean, vegetation, and soil reservoirs. Ten to twenty five-year cycles of drought and fire are not recorded as individual excursions in the soil reservoir as the rate of transfer between the vegetation and soil reservoirs homogenizes the signal. A wildfire-modeled excursion does not propagate a geologically significant excursion through time. Combustion of a peat reservoir is necessary to drive and validate a geologically and isotopically significant excursion. Assuming 0.5% of the standing early Cretaceous peat reservoir is consumed by fire for each year for ten years coupled with the earlier scenario, the atmospheric CO2 increases from 2.0 to 3.1x P.A.L., atmosphere, vegetation, and the surface ocean record a negative carbon isotope excursion of -5.1 ‰ , -3.8 ‰ and -1.8 ‰ respectively, with a duration of 741 years. Increasing the size of the vegetation reservoir translates the excursions from the centennial to millennial scale. For example, doubling the vegetation reservoir (from 1.4 to 2.8E+16 gC) for a 25 year global peat conflagration (0.5% combusted each year) results in a CO2 increase from 2.0 to 4.0x P.A.L., and the atmosphere, vegetation, and the surface ocean reservoirs with a negative carbon isotope excursion of -5.7 ‰ , -8.7 ‰ and -2.3 ‰ respectively. Addition of carbonaceous aerosols (black carbon and polycyclic aromatic hydrocarbons) to pelagic marine sediments could potentially serve as a high-resolution record of ancient fires and firmly tie isotopic shifts to paleofires.

Drain blocking: an effective treatment for reducing dissolved organic carbon loss and water discolouration in a drained peatland.

PubMed

Wallage, Zoe E; Holden, Joseph; McDonald, Adrian T

2006-08-31

Peatlands are an important terrestrial carbon store. However, heightened levels of degradation in response to environmental change have resulted in an increased loss of dissolved organic carbon (DOC) and an associated rise in the level of discolouration in catchment waters. A significant threat to peatland sustainability has been the installation of artificial drainage ditches. However, recent restoration schemes have pursued drain blocking as a possible strategy for reducing degradation, fluvial carbon loss and water discolouration. This paper investigates the effect of open cut drainage and the impact of drain blocking on DOC and colour dynamics in blanket peat soil-water solutions. Three treatments (intact peat, drained peat and drain-blocked peat) were monitored in an upland blanket peat catchment in the UK. DOC and colour values were significantly higher on the drained slopes compared with those of the intact peat, which in turn had greater DOC and colour values than the drain-blocked slopes. Consequently, drain blocking is shown to be a highly successful technique in reducing both the DOC concentration and level of discolouration in soil waters, even to values lower than those observed for the intact site, which suggests a process of store exhaustion and flushing may operate. The colour per carbon unit (C/C) ratio was significantly higher at the drain-blocked site than either the intact or the drained treatments, while the E4/E6 ratio (fulvic acid/humic acid) was significantly lower at the blocked site compared to the two other treatments. The high C/C and low E4/E6 ratios indicate that drain blocking also modifies the composition of DOC, such that darker-coloured humic substances become more dominant compared to the intact site. This implies disturbance to DOC production and/or transportation processes operating within the peat.

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.; Hsieh, I. F.; Giasson, M. A.

2016-12-01

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. Here we report soil iCO2 and iCH4 flux responses to the first year of belowground warming and the first season of whole ecosystem warming and elevated CO2 treatments. We find that peat methane fluxes are more sensitive to warming treatments than peat CO2 fluxes, particularly in hollow peat microforms. Surface CO2:CH4 flux ratios decreased across warming treatments, suggesting that the temperature sensitivity of methane production overshadows the effect of peat drying and surface aeration in the short term. δ13C of the emitted methane was more depleted in the early and late growing season, indicating a transition from hydrogenotrophic to acetoclastic methanogenesis during periods of high photosynthetic input. The measurement record demonstrates that belowground warming has measureable impacts on the nature of peat greenhouse gas emission within one year of treatment.

Using Multitemporal and Multispectral Airborne Lidar to Assess Depth of Peat Loss and Correspondence With a New Active Normalized Burn Ratio for Wildfires

NASA Astrophysics Data System (ADS)

Chasmer, L. E.; Hopkinson, C. D.; Petrone, R. M.; Sitar, M.

2017-12-01

Accuracy of depth of burn (an indicator of consumption) in peatland soils using prefire and postfire airborne light detection and ranging (lidar) data is determined within a wetland-upland forest environment near Fort McMurray, Alberta, Canada. The relationship between peat soil burn depth and an "active" normalized burn ratio (ANBR) is also examined beneath partially and fully burned forest and understory canopies using state-of-the-art active reflectance from a multispectral lidar compared with normalized burn ratio (NBR) derived from Landsat 7 ETM+. We find significant correspondence between depth of burn, lidar-derived ANBR, and difference NBR (dNBR) from Landsat. However, low-resolution optical imagery excludes peatland burn losses in transition zones, which are highly sensitive to peat loss via combustion. The findings presented here illustrate the utility of this new remote sensing technology for expanding an area of research where it has previously been challenging to spatially detect and quantify such wildfire burn losses.

A comparative study on the influence of different organic amendments on trace element mobility and microbial functionality of a polluted mine soil.

PubMed

Abad-Valle, P; Iglesias-Jiménez, E; Álvarez-Ayuso, E

2017-03-01

A mine soil heavily polluted with zinc and cadmium was employed to evaluate the capacity of organic amendments of different origin to simultaneously reduce soil trace element mobility and enhance soil microbial functionality. With this aim, four organic products, namely olive processing solid waste (OPSW), municipal solid waste compost (MSWC), leonardite and peat, were applied individually at different doses (0, 1, 2 and 5%) to mine soil under controlled laboratory conditions. Extraction studies and analysis of soil microbiological parameters (basal soil respiration and dehydrogenase, β-glucosidase, urease, arylsulfatase and acid and alkaline phosphatase activities) were performed to assess the effect of such amendments on soil restoration. Their ability to decrease mine soil mobile trace element contents followed the sequence MSWC > OPSW > peat > leonardite, with the former achieving reduction levels of 78 and 73% for Zn and Cd, respectively, when applied at a dose of 5%. This amendment also showed a good performance to restore soil microbial functionality. Thus, basal soil respiration and dehydrogenase, urease and alkaline phosphatase activities experienced increases of 187, 79, 42 and 26%, respectively, when mine soil was treated with 5% MSWC. Among tested organic products, MSWC proved to be the best amendment to perform both the chemical and the microbial soil remediation. Copyright © 2016 Elsevier Ltd. All rights reserved.

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...

Stability of peatland carbon to rising temperatures

DOE PAGES

Wilson, R. M.; Hopple, A. M.; Tfaily, M. M.; ...

2016-12-13

Peatlands contain one-third of soil carbon (C), mostly buried in deep, saturated anoxic zones (catotelm). The response of catotelm C to climate forcing is uncertain, because prior experiments have focused on surface warming. Here, we show that deep peat heating of a 2 m-thick peat column results in an exponential increase in CH 4 emissions. But, this response is due solely to surface processes and not degradation of catotelm peat. Incubations show that only the top 20–30 cm of peat from experimental plots have higher CH 4 production rates at elevated temperatures. Radiocarbon analyses demonstrate that CH 4 and COmore » 2 are produced primarily from decomposition of surface-derived modern photosynthate, not catotelm C. Furthermore, there are no differences in microbial abundances, dissolved organic matter concentrations or degradative enzyme activities among treatments. Our results suggest that although surface peat will respond to increasing temperature, the large reservoir of catotelm C is stable under current anoxic conditions.« less

Stability of peatland carbon to rising temperatures

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

Wilson, R. M.; Hopple, A. M.; Tfaily, M. M.

Peatlands contain one-third of soil carbon (C), mostly buried in deep, saturated anoxic zones (catotelm). The response of catotelm C to climate forcing is uncertain, because prior experiments have focused on surface warming. Here, we show that deep peat heating of a 2 m-thick peat column results in an exponential increase in CH 4 emissions. But, this response is due solely to surface processes and not degradation of catotelm peat. Incubations show that only the top 20–30 cm of peat from experimental plots have higher CH 4 production rates at elevated temperatures. Radiocarbon analyses demonstrate that CH 4 and COmore » 2 are produced primarily from decomposition of surface-derived modern photosynthate, not catotelm C. Furthermore, there are no differences in microbial abundances, dissolved organic matter concentrations or degradative enzyme activities among treatments. Our results suggest that although surface peat will respond to increasing temperature, the large reservoir of catotelm C is stable under current anoxic conditions.« less

Use of CT imaging to examine the coarse roots, rhizomes, and peat associated with creek bank Spartina alterniflora in fertilized and control creeks in Plum Island (MA)

EPA Science Inventory

We used computer-aided tomography (CT) to quantify the wet mass, abundance, and diameter of coarse roots and rhizomes as well as the wet mass and particle density of marsh peat in 7-year fertilized and control creeks in Plum Island (MA). In shallow soils (0 – 10 cm) and at dep...

CO2 emissions from organic soils under agricultural use

NASA Astrophysics Data System (ADS)

Bader, Cédric; Leifeld, Jens; Müller, Moritz; Schulin, Rainer

2015-04-01

The organic soils of peatlands represent a major global sink for terrestrial carbon. Agricultural use of organic soils requires drainage, changing conditions in these soils from anoxic to oxic. As a consequence, the organic carbon that had been accumulated often over millennia is rapidly mineralized, so that these soils then are no longer a sink but become a source of CO2. The aim of our study is to analyse the amount and origin of CO2 emitted from organic soils under three land-use types (forest, arable cropland and grassland). Our study area is located in the Bernese Lakeland (CH). The peatlands of this region were drained in the 1870ies, and the site as well as the surrounding area are now managed by a state prison. Since decades our study site is under the same land-use. In Oktober 2013 we took 4 replicate soil cores of all land-uses with respect to a certain distance from a major drainage ditch. Each core was analysed for its bulk density and carbon content. 9 soil samples from a depth of 20-30 cm were analysed for their F14C and δ13C values and later divided into 18 subsamples. Half of them were mixed with 0.2-0.4 g of labelled corn stalk enriched in δ13C (δ13C=2000) in order to mimic plant residue inputs in the field. The moisture content of these samples was equilibrated at a pF-value of 2 before incubating the samples in a Respicond VII analyser for several weeks at 20° C. By trapping the respired CO2 in NaOH and precipitating it as BaCO3 we were able to analyse its F14C and δ13C value. This enabled us to determine to what extent the CO2 originated from old peat, young plant residues or the added maize stalk. Generally the cropland samples showed the highest respiration rates, lowest F14C values and highest carbon stocks. The organic soils under the forest were degraded the most and showed low respiration rates. Analyzing the F14C values of the CO2 revealed that peat contributes most to the respiration and its degradation is fastest in the cropland. Our findings suggest that peat respiration must have been more intense under forest during the past 140 years. The addition of fresh plant material resulted in increased respiration rates but supressed the respiration of old peat in the cropland and grassland (negative priming).

Peat accumulation in drained thermokarst lake basins in continuous, ice-rich permafrost, northern Seward Peninsula, Alaska

USGS Publications Warehouse

Jones, Miriam C.; Grosse, Guido; Jones, Benjamin M.; Anthony, Katey Walter

2012-01-01

Thermokarst lakes and peat-accumulating drained lake basins cover a substantial portion of Arctic lowland landscapes, yet the role of thermokarst lake drainage and ensuing peat formation in landscape-scale carbon (C) budgets remains understudied. Here we use measurements of terrestrial peat thickness, bulk density, organic matter content, and basal radiocarbon age from permafrost cores, soil pits, and exposures in vegetated, drained lake basins to characterize regional lake drainage chronology, C accumulation rates, and the role of thermokarst-lake cycling in carbon dynamics throughout the Holocene on the northern Seward Peninsula, Alaska. Most detectable lake drainage events occurred within the last 4,000 years with the highest drainage frequency during the medieval climate anomaly. Peat accumulation rates were highest in young (50–500 years) drained lake basins (35.2 g C m−2 yr−1) and decreased exponentially with time since drainage to 9 g C m−2 yr−1 in the oldest basins. Spatial analyses of terrestrial peat depth, basal peat radiocarbon ages, basin geomorphology, and satellite-derived land surface properties (Normalized Difference Vegetation Index (NDVI); Minimum Noise Fraction (MNF)) from Landsat satellite data revealed significant relationships between peat thickness and mean basin NDVI or MNF. By upscaling observed relationships, we infer that drained thermokarst lake basins, covering 391 km2 (76%) of the 515 km2 study region, store 6.4–6.6 Tg organic C in drained lake basin terrestrial peat. Peat accumulation in drained lake basins likely serves to offset greenhouse gas release from thermokarst-impacted landscapes and should be incorporated in landscape-scale C budgets.

Evaluation of a peat moss plus soybean oil (PMSO) technology for reducing explosive residue transport to groundwater at military training ranges under field conditions.

PubMed

Fuller, Mark E; Schaefer, Charles E; Steffan, Robert J

2009-11-01

An evaluation of peat moss plus crude soybean oil (PMSO) for mitigation of explosive contamination of soil at military facilities was performed using large soil lysimeters under field conditions. Actual range soils were used, and two PMSO preparations with different ratios of peat moss:soybean oil (1:1, PO1; 1:2, PO2) were compared to a control lysimeter that received no PMSO. PMSO was applied as a 10 cm layer on top of the soil, and Composition B detonation residues from a 55-mm mortar round were applied at the surface of each of the lysimeters. Dissolution of the residues occurred during natural precipitation events over the course of 18 months. Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) emanating from the Composition B residues were significantly reduced by the PO2 PMSO material compared to the untreated control. Soil pore water RDX concentrations and RDX fluxes were reduced over 100-fold compared to the control plots at comparable depths. Residual RDX in the soil profile was also significantly lower in the PMSO treated plots. PO1 PMSO resulted in lower reductions in RDX transport than the PO2 PMSO. The transport of the RDX breakdown product hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) was also greatly reduced by the PMSO materials. Results were in general agreement with a previously developed fate and transport model describing PMSO effectiveness. These results demonstrate the potential effectiveness of the inexpensive and environmentally benign PMSO technology for reducing the subsurface loading of explosives at training ranges and other military facilities.

7 CFR 301.85 - Quarantine; restriction on interstate movement of specified regulated articles.

Code of Federal Regulations, 2013 CFR

2013-01-01

...) Soil, compost, humus, muck, peat, and decomposed manure, separately or with other things. (2) Plants with roots, except soil-free aquatic plants. (3) Grass sod. (4) Plant crowns and roots for propagation... measurement by a sizing screen or sizing chain, each is substantially free of soil as a result of grading (a...

7 CFR 301.85 - Quarantine; restriction on interstate movement of specified regulated articles.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) Soil, compost, humus, muck, peat, and decomposed manure, separately or with other things. (2) Plants with roots, except soil-free aquatic plants. (3) Grass sod. (4) Plant crowns and roots for propagation... measurement by a sizing screen or sizing chain, each is substantially free of soil as a result of grading (a...

7 CFR 301.85 - Quarantine; restriction on interstate movement of specified regulated articles.

Code of Federal Regulations, 2012 CFR

2012-01-01

...) Soil, compost, humus, muck, peat, and decomposed manure, separately or with other things. (2) Plants with roots, except soil-free aquatic plants. (3) Grass sod. (4) Plant crowns and roots for propagation... measurement by a sizing screen or sizing chain, each is substantially free of soil as a result of grading (a...

7 CFR 301.85 - Quarantine; restriction on interstate movement of specified regulated articles.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) Soil, compost, humus, muck, peat, and decomposed manure, separately or with other things. (2) Plants with roots, except soil-free aquatic plants. (3) Grass sod. (4) Plant crowns and roots for propagation... measurement by a sizing screen or sizing chain, each is substantially free of soil as a result of grading (a...

7 CFR 301.85 - Quarantine; restriction on interstate movement of specified regulated articles.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) Soil, compost, humus, muck, peat, and decomposed manure, separately or with other things. (2) Plants with roots, except soil-free aquatic plants. (3) Grass sod. (4) Plant crowns and roots for propagation... measurement by a sizing screen or sizing chain, each is substantially free of soil as a result of grading (a...

Physical properties of organic soils. Chapter 5.

Treesearch

Elon S. Verry; Don H. Boelter; Juhani Paivanen; Dale S. Nichols; Tom Malterer; Avi Gafni

2011-01-01

Compared with research on mineral soils, the study of the physical properties of organic soils in the United States is relatively new. A comprehensive series of studies on peat physical properties were conducted by Don Boelter (1959-1975), first at the Marcell Experimental Forest (MEF) and later throughout the northern Lakes States to investigate how to express bulk...

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

NASA Astrophysics Data System (ADS)

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

2012-04-01

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

Distribution and mobility of lead (Pb), copper (Cu), zinc (Zn), and antimony (Sb) from ammunition residues on shooting ranges for small arms located on mires.

PubMed

Mariussen, Espen; Johnsen, Ida Vaa; Strømseng, Arnljot Einride

2017-04-01

An environmental survey was performed on shooting ranges for small arms located on minerotrophic mires. The highest mean concentrations of Pb (13 g/kg), Cu (5.2 g/kg), Zn (1.1 g/kg), and Sb (0.83 g/kg) in the top soil were from a range located on a poor minerotrophic and acidic mire. This range had also the highest concentrations of Pb, Cu, Zn, and Sb in discharge water (0.18 mg/L Pb, 0.42 mg/L Cu, 0.63 mg/L Zn, and 65 μg/L Sb) and subsurface soil water (2.5 mg/L Pb, 0.9 mg/L Cu, 1.6 mg/L Zn, and 0.15 mg/L Sb). No clear differences in the discharge of ammunition residues between the mires were observed based on the characteristics of the mires. In surface water with high pH (pH ~7), there was a trend with high concentrations of Sb and lower relative concentrations of Cu and Pb. The relatively low concentrations of ammunition residues both in the soil and soil water, 20 cm below the top soil, indicates limited vertical migration in the soil. Channels in the mires, made by plant roots or soil layer of less decomposed materials, may increase the rate of transport of contaminated surface water into deeper soil layers and ground water. A large portion of both Cu and Sb were associated to the oxidizable components in the peat, which may imply that these elements form inner-sphere complexes with organic matter. The largest portion of Pb and Zn were associated with the exchangeable and pH-sensitive components in the peat, which may imply that these elements form outer-sphere complexes with the peat.

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

NASA Astrophysics Data System (ADS)

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

2016-12-01

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

Secondary successions of biota in oil-polluted peat soil upon different biological remediation methods

NASA Astrophysics Data System (ADS)

Melekhina, E. N.; Markarova, M. Yu.; Shchemelinina, T. N.; Anchugova, E. M.; Kanev, V. A.

2015-06-01

The effects of different bioremediation methods on restoration of the oil-polluted peat soil (Histosol) in the northernmost taiga subzone of European Russia was studied. The population dynamics of microorganisms belonging to different trophic groups (hydrocarbon-oxidizing, ammonifying, nitrifying, and oligonitrophilic) were analyzed together with data on the soil enzyme (catalase and dehydrogenase) activities, population densities of soil microfauna groups, their structures, and states of phytocenoses during a sevenyear-long succession. The remediation with biopreparations Roder composed of oil-oxidizing microorganisms-Roder with Rhodococcus rubber and R. erythropolis and Universal with Rhodotorula glutinis and Rhodococcus sp.-was more efficient than the agrochemical and technical remediation. It was concluded that the biopreparations activate microbiological oil destruction, thereby accelerating restoration succession of phytocenosis and zoocenosis. The succession of dominant microfauna groups was observed: the dipteran larvae and Mesostigmata mites predominant at the early stages were replaced by collembolans at later stages. The pioneer oribatid mite species were Tectocepheus velatus, Oppiella nova, Liochthonius sellnicki, Oribatula tibialis, and Eupelops sp.

Designing the ideal habitat for entomopathogen use in nursery production.

PubMed

Nielsen, Anne L; Lewis, Edwin E

2012-07-01

Greenhouse and nursery producers use entomopathogens (nematodes and fungi) to control soil pests. Although it is known that the physical and chemical properties of mineral soil significantly impact upon soil pathogens, the influence of soilless media used for plant production on entomopathogen performance is poorly understood. Survival and foraging distance were differently affected by sand:peat, bark and sawdust media for entomopathogenic nematodes, but not for the immobile fungus Metarhizium anisopliae. Redwood sawdust medium consistently had a negative impact upon entomopathogenic nematodes. Dividing media into individual components supported the hypothesis that redwood sawdust reduced foraging and infection abilities of S. riobrave and H. bacteriophora. Physically altering the components by adding sand significantly improved foraging and infection success for S. riobrave in media not optimum for foraging. This study is the first to highlight the importance of selecting the appropriate soilless media and pathogen species combinations to increase efficacy of biological control. H. bacteriophora was able to find hosts in a wider diversity of medium components than S. riobrave, although both nematode species performed well in peat moss and recycled plant material. These results suggest that peat moss, recycled plant material and hardwood bark are components amenable to EPN biological control programs. Copyright © 2012 Society of Chemical Industry.

Physicochemical and Microbiological Characteristics of Tundra Soils on the Rybachii Peninsula

NASA Astrophysics Data System (ADS)

Evdokimova, G. A.; Mozgova, N. P.; Myazin, V. A.

2018-01-01

The Rybachii Peninsula is composed of Proterozoic sedimentary rocks and differs sharply from the rest of the Kola Peninsula in its geological structure, topographic forms, and parent rocks. It is dominated by Al-Fe-humus soils formed on moraines with an admixture of local rock fragments, including slates. Organic horizons of tundra soils in the peninsula are less acid than those on granitoids of adjacent mainland of the Kola Peninsula. The content of exchangeable calcium in the organic horizons varies from 17.4 to 68.0 cmolc/kg, and the content of water-soluble carbon reaches 400 mg/100 g amounting to 1-2% of the total soil organic matter content. The total number of bacteria in the organic horizons of tundra soils varies from 3.5 × 109 to 4.8 × 109 cells/g; and bacterial biomass varies from 0.14 to 0.19 mg/g. The length of fungal mycelium and its biomass in the organic horizons are significant (>1000 m/g soil). The biomass of fungal mycelium in the organic horizons exceeds the bacterial biomass by seven times in podzols (Albic Podzols) and by ten times in podbur (Entic Podzol), dry-peat soil (Folic Histosol), and low-moor peat soil (Sapric Histosol).

Development of new peat based growing media by addition of pruning waste and biochars

NASA Astrophysics Data System (ADS)

Nieto, Aurora; Gascó, Gabriel; Paz-Ferreiro, Jorge; Plaza, César; Fernández, José Manuel; Méndez, Ana

2015-04-01

In the last years, several researches have been performed to find high quality and low cost substrates from different organic wastes in order to decrease peat consumption since the indiscriminate exploitation of peat lands is exhausting this non-renewable useful resource and destroying endangered wetland ecosystems worldwide. The use of organic wastes as soil amendments or possible peat substitute could be improved by pyrolysis treatment, leading to biochar, a carbon-rich material that has attached important attention. Our research group has been worked in the formulation of new based-growing media by peat substitution in 50 and 75 vol% of pruning waste (PW), commercial charcoal (CC), biochar from PW at 300°C (B300) and 500°C (B500). Growing media show adequate physicochemical and hydrophysical properties. Experiments performed with lettuce germination show that PW addition in a 75vol% reduces germination index probably due to their high content on phenolic compounds. Lettuce growing experiments were performed during 5 weeks and show that addition of PW and CC to peat decreases biomass production whereas; B300 and specially, B500 addition significantly increases the lettuce biomass.

Soil Nitrification and N2O Production: the connection with N concentration and Soil Water Content

NASA Astrophysics Data System (ADS)

Zhu-Barker, X.; Horwath, W. R.

2016-12-01

The development of mitigation strategies to reduce nitrous oxide (N2O) emission from soils is dependent on explicating the biophysical factors affecting different N2O production pathways. Ammonia oxidation and heterotrophic denitrification are the main pathways of N2O production, depending on soil conditions such as soil moisture content, oxygen (O2) content and N substrate. Many researchers have reported that N2O production increased as substrate concentration and soil moisture content increased. However, less understood is how N fertilizer concentration and moisture content interact to affect N2O production pathways. To investigate interaction and its effect on O2 consumption, we incubated three agricultural soils (clay, sandy loam, and peat) with different concentrations of (NH4)2SO4 (0-1000 µg N g-1) under 50 %, 75%, and 100% of water holding capacity. All treatments received 15N -KNO3 to bring the concentrations of NO3-_N in soils to 50 mg kg-1 soil and the NO3- pool to an enrichment of 10 atom% 15N. In all soils, the total amount of O2 consumption and N2O production increased as soil ammonical N concentration increased. The increased soil moisture significantly promoted N2O production in sandy loam and clay loam soils, compared to the peat soil. These results indicate that N2O production increased as substrate concentration increased likely due to the onset of O2 limitation caused by ammonia oxidation.

Polycyclic aromatic hydrocarbons in post-fire soils of drained peatlands in western Meshchera (Moscow region, Russia)

NASA Astrophysics Data System (ADS)

Tsibart, A.; Gennadiev, A.; Koshovskii, T.; Watts, A.

2014-12-01

Polycyclic aromatic hydrocarbons (PAHs) are priority pollutants that arrive in the environment from numerous anthropogenic and natural sources, but the data on their natural sources including wildfires remain insufficient. The level of contamination and the composition of PAHs in soils of the areas affected by wildfires were studied in this work. The study was conducted in the Moscow region (Russia) in areas occupied by drained peatland and strongly damaged by fires in 2002, 2010 and 2012. The features of PAH accumulation and the profile distributions in histosols and histic podzols after the fires of different times were analyzed. It was shown that new soil horizons formed after the fires - Cpir, Hpir and incipient O horizons - and that these horizons differ in PAH accumulation rate. Maximal total concentrations of 14 PAHs were detected in charred peat horizons Hpir (up to 330 ng g-1) and in post-fire incipient O horizons (up to 180 ng g-1), but the high-molecular-weight PAHs (benz(ghi)perylene, benz(a)pyrene, benz(k)fluoranthene) were revealed only in charry peat horizons. The trends of higher PAH concentrations were found in cases when smoldering combustion resulted in rather thick residual peat horizons. In cases of almost complete pyrogenic destruction of He horizons, total PAH concentrations were no more than 50 ng g-1. Also, PAH accumulation in upper horizons of soils near the sites of the latest fires was observed.

Polycyclic aromatic hydrocarbons in post-pyrogenic soils of drained peatlands in West Meshchera (Moscow Region, Russia)

NASA Astrophysics Data System (ADS)

Tsibart, A. S.; Gennadiev, A. N.; Koshovskii, T. S.

2014-05-01

Polycyclic aromatic hydrocarbons (PAHs) are priority pollutants and they arrive to the environment from numerous anthropogenic and natural sources, but the data on their natural sources which include wildfires remains insufficient. The level of contamination and the composition of PAHs in soils of the areas affected by wildfires were studied in this work. The study was conducted in Moscow Region (Russia) on the territories occupied with drained peatland and strongly damaged by fires of 2002, 2010 and 2012. The features of PAHs accumulation and profile distribution in histosols and histic podzols after the fires of different time were analyzed. It was shown that new soil horizon form after the fires - Cpir, Hpir and incipient O horizons, and these horizons differ in PAHs accumulation rate. Maximal total concentrations of 14 PAHs were detected in charry peat horizons Hpir (up to 330 ng g-1) and in post-pyrogenic incipient O horizons (up to 180 ng g-1), but the high-molecular weight PAHs (benz(ghi)perylene, benz(a)pyrene, benz(k)fluoranthene) were revealed only in charry peat horizons. The trends to higher PAHs concentrations were found in cases of incomplete burning out of peat horizons while in cases of almost complete pyrogenic destruction of He horizons total PAHs concentration were no more than 50 ng g-1. Also the PAHs accumulation in upper horizons of soils near the sites of latest fires was observed.

A Few Issues on the Peat Research in the Altai Mountains

NASA Astrophysics Data System (ADS)

Inisheva, Lydia I.; Larina, Galina; Shurova, Maya

2010-05-01

At the present time we carry out complex research of marsh ecosystems in various areas of Gorny Altai to reveal the perspective deposits of peat in the Altai Mountains with the purpose of its use in the medical and recreational spheres. The peat deposits of the Northeastern Altai, Central Altai, and Southeastern Altai are surveyed; the selective chemical analysis of peat and marsh waters is carried out. The group structure of organic substance of various samples of peat is investigated by the method of Institutes of Peat. The toxic metals of Cd, Pb, Hg, Cu, Zn, and As were defined by the method of stripping voltammetry. The region of the Altai Mountains is characterized by the contrastive distribution of some heavy metals and arsenic in a soil cover. This is caused by a variety of petrography and granulometry of soil forming material, and also by a landscape and geochemical situation in the system of vertical zoning. The sources of natural accumulation of heavy metals in the ground might be the deposits of polymetals. In this connection the content of the specified toxic elements in the peat under research has been identified. The peat of the Turochak deposit is characterized by a significant ash content - up to 41,9%; the increased ash content is typical of the Kutyush deposit: from 6,1% up to 19, %. The peat of the Northeastern Altai is referred to non-bitumunous: the content of bitumen makes up less than 5%. In comparison with the European peat the peat under study of the transitive and lowland type is characterized by the significant content of easy hydrolysable substances in the amount of 24,8-41,1%. The amount of the non-hydrolysable rest makes up around 4,3 - 7,4 %. The total content of fulvic acids is less than the content of humic acids by 2,9 - 5,8 times. The high content of humic acids which can reach up to 58 % is characteristic of certain deposits. Humic acids extracted from the peat are characterized, as a rule, by similar IR-spectra. The distinctions are shown in an unequal intensity of characteristic absorption bands, in their spreading and some shifts. It is revealed that humic acids of peat with the increase in a degree of decomposition are exposed to transformation; therefore the increase in their structure of functional groups is observed. As a result of the research which was carried out the following elements among heavy metals in the lowland peat of the Altai Mountains are revealed: Cd (2,7 - 30)> Hg (0,67)> Zn (0,22) ~Pb (0,21)> Cu (0,13)> As (0,03). The degree of mobility of chemical elements in the peat varies within the limits of 1,3 - 36%. According to the degree of their mobility these elements form the following line: Zn (36 %)> Pb (18,1 %)> Cd (9,6 %)> Cu (1,3 %). The content and the character of distribution of the heavy metals under study and arsenic in the peat of the Altai Mountains have their unique features in comparison with the same valley analogues. The mountain peat of the Central Altai contains much less Hg than the West Siberian one: 0,078 mg/g and 0,69 mg/g accordingly. Cd represents itself as the concentrator in the lowland peat of the Northeastern and Central Altai, its content is actually the same and makes up approximately 0,3 mg/kg. The lowland Altai and West Siberian peat has the same amount of Pb: 4-5 mg/kg; they have smaller amounts of Zn and Cu in comparison with the European and West Siberian peat. The revealed features of distribution of some toxic metals are the display of specificity of peat genesis in the conditions of a mountain relief. The complex of the data received by us allows to consider the peat of the Altai Mountains as a non-polluting raw source concerning the amount of some natural toxic substances. The possible perspective directions of practical application of the mountain peat can be medicine, veterinary science, and agriculture.

Management effects on greenhouse gas emissions from a fen covered with riverine silt

NASA Astrophysics Data System (ADS)

Bräuer, Melanie; Gatersleben, Peter; Tiemeyer, Bärbel

2017-04-01

Drainage is necessary to use peatlands for conventional agriculture, but this practice causes high emissions of the greenhouse gases carbon dioxide (CO2) and nitrous oxide (N2O). The effect of hydrological conditions and management on greenhouse gas (GHG) emissions from "true" peat soils is relatively well examined, but there is little data on GHG emissions from organic soils covered with mineral soil. Such a cover may either be man-made to improve the trafficability of the fields or natural, e.g. due to the deposition of riverine silt. Such mineral covers are widespread in North-Western Germany and other regions with intensively used peatlands. Here, we aim to evaluate the effect of management, water table depth and properties of the mineral cover on the emissions of CO2, N2O and methane (CH4). As the majority of peatlands in North-Western Germany, the study area is used as grassland. The area is artificially drained and intensively used (4 to 5 cuts per year, annual nitrogen fertilisation of 112 to 157 kg/ha). The fen peat with a thickness of 0.6 to 1.50 m is covered by riverine silt deposited by the river Weser. Six measurement sites have been chosen to represent typical agricultural management, soil properties and hydrological conditions of one hydrological management unit. The sites differ in the soil organic carbon (SOC) content of the riverine silt (4 - 15 % SOC), the occurrence of a ploughed horizon as well as water and agricultural management. We use static closed chambers to measure CO2, CH4 and N2O fluxes. CO2 measurement campaigns using transparent and opaque chambers and a portable IRGA take place every third or fourth week depending on season. CH4 and N2O samples are taken every second week and, in addition, on the first, third and seventh day after fertilizer application. Samples are analyzed by gas chromatography. First results show negligible CH4 fluxes due to low groundwater levels. Total N2O emissions reflected mainly the different fertilizer application rates although there were rarely specific N2O peaks directly after fertilizer application, probably due to low soil moisture during these periods. Estimated from the first six months of data, N2O emissions from peat soils covered with riverine silt are in the same range as emissions from true peat soils with comparable fertilisation rates. First results on CO2 emissions will be presented as well.

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

NASA Astrophysics Data System (ADS)

McGlone, M. S.

2002-02-01

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

Contaminated lead environments of man: reviewing the lead isotopic evidence in sediments, peat, and soils for the temporal and spatial patterns of atmospheric lead pollution in Sweden.

PubMed

Bindler, Richard

2011-08-01

Clair Patterson and colleagues demonstrated already four decades ago that the lead cycle was greatly altered on a global scale by humans. Moreover, this change occurred long before the implementation of monitoring programs designed to study lead and other trace metals. Patterson and colleagues also developed stable lead isotope analyses as a tool to differentiate between natural and pollution-derived lead. Since then, stable isotope analyses of sediment, peat, herbaria collections, soils, and forest plants have given us new insights into lead biogeochemical cycling in space and time. Three important conclusions from our studies of lead in the Swedish environment conducted over the past 15 years, which are well supported by extensive results from elsewhere in Europe and in North America, are: (1) lead deposition rates at sites removed from major point sources during the twentieth century were about 1,000 times higher than natural background deposition rates a few thousand years ago (~10 mg Pb m(-2) year(-1) vs. 0.01 mg Pb m(-2) year(-1)), and even today (~1 mg Pb m(-2) year(-1)) are still almost 100 times greater than natural rates. This increase from natural background to maximum fluxes is similar to estimated changes in body burdens of lead from ancient times to the twentieth century. (2) Stable lead isotopes ((206)Pb/(207)Pb ratios shown in this paper) are an effective tool to distinguish anthropogenic lead from the natural lead present in sediments, peat, and soils for both the majority of sites receiving diffuse inputs from long range and regional sources and for sites in close proximity to point sources. In sediments >3,500 years and in the parent soil material of the C-horizon, (206)Pb/(207)Pb ratios are higher, 1.3 to >2.0, whereas pollution sources and surface soils and peat have lower ratios that have been in the range 1.14-1.18. (3) Using stable lead isotopes, we have estimated that in southern Sweden the cumulative anthropogenic burden of atmospherically deposited lead is ~2-5 g Pb m(-2) and ~1 g Pb m(-2) in the "pristine" north. Half of this cumulative total was deposited before industrialization. (4) In the vicinity of the Rönnskär smelter in northern Sweden, a major point source during the twentieth century, there is an isotopic pattern that deviates from the general trends elsewhere, reflecting the particular history of ore usage at Rönnskär, which further demonstrates the chronological record of lead loading recorded in peat and in soil mor horizons.

Revegetation processes and environmental conditions in abandoned peat production fields in Estonia

NASA Astrophysics Data System (ADS)

Orru, M.; Orru, H.

2009-04-01

As a result of peat extraction, peat production has been finished in Estonia at different times in 154 peat production areas and 9,500 ha (~1% of peatlands) are abandoned, although the peat reserves are not exhausted yet; besides, several areas are not properly recultivated. In addition 12,000 ha of fens (oligotrophic peat layers) are drained and used as grasslands. If the abandoned and non-recultivated peat production areas are not vegetated, their CO2 emission is considerable and peat mineralises in such areas. The aim of the study was to find out specific ecological and geological factors, which affect recovering of peatlands and influence the recultivation. During the revision the amount and quality of the remained reserves, as well as the state of water regime, drainage network and revegetation was assessed in all 154 abandoned peat production areas. The study showed that the state of them is very variable. Some of them are covered with forest, prevailingly with birches at former drainage ditches, later supplemented by pine trees. In the others predominate grasses among plants, and various species of moss (Cladonia rei, Bryum caespiticum, Sphagnum ripariuma, Sphagnum squarrosum) occur as well. Besides, some abandoned areas are completely overgrown with cotton grass. Open abandoned peat areas, which are not covered by vegetation, are much rarer. We found out, that water regime among the factors plays most important role. Moreover abandoned peat production fields, where the environmental conditions have changed - are appropriate for growth of several moss species, which cannot inhabit the areas already occupied by other species. The most interesting discovers were: second growing site of Polia elongata in West-Estonia and Ephemerum serratum, last found in Estonia in the middle of the 19th century, was identified in central Estonia. Also Campylopus introflexus, what was unknown in Estonia. However, the changes in environmental conditions influence the peat layers structure and technical characteristics of organic soils that affect the vegetation of peatlands.

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

NASA Astrophysics Data System (ADS)

Loisel, Julie; Yu, Zicheng

2014-05-01

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

Experimental determination of soil heat storage for the simulation of heat transport in a coastal wetland

NASA Astrophysics Data System (ADS)

Swain, Michael; Swain, Matthew; Lohmann, Melinda; Swain, Eric

2012-02-01

SummaryTwo physical experiments were developed to better define the thermal interaction of wetland water and the underlying soil layer. This information is important to numerical models of flow and heat transport that have been developed to support biological studies in the South Florida coastal wetland areas. The experimental apparatus consists of two 1.32 m diameter by 0.99 m tall, trailer-mounted, well-insulated tanks filled with soil and water. A peat-sand-soil mixture was used to represent the wetland soil, and artificial plants were used as a surrogate for emergent wetland vegetation based on size and density observed in the field. The tanks are instrumented with thermocouples to measure vertical and horizontal temperature variations and were placed in an outdoor environment subject to solar radiation, wind, and other factors affecting the heat transfer. Instruments also measure solar radiation, relative humidity, and wind speed. Tests indicate that heat transfer through the sides and bottoms of the tanks is negligible, so the experiments represent vertical heat transfer effects only. The temperature fluctuations measured in the vertical profile through the soil and water are used to calibrate a one-dimensional heat-transport model. The model was used to calculate the thermal conductivity of the soil. Additionally, the model was used to calculate the total heat stored in the soil. This information was then used in a lumped parameter model to calculate an effective depth of soil which provides the appropriate heat storage to be combined with the heat storage in the water column. An effective depth, in the model, of 5.1 cm of wetland soil represents the heat storage needed to match the data taken in the tank containing 55.9 cm of peat/sand/soil mix. The artificial low-density laboratory sawgrass reduced the solar energy absorbed by the 35.6 cm of water and 55.9 cm of soil at midday by less than 5%. The maximum heat transfer into the underlying peat-sand-soil mix lags behind maximum solar radiation by approximately 2 h. A slightly longer temperature lag was observed between the maximum solar radiation and maximum water temperature both with and without soil.

Experimental determination of soil heat storage for the simulation of heat transport in a coastal wetland

USGS Publications Warehouse

Swain, Michael; Swain, Matthew; Lohmann, Melinda; Swain, Eric

2012-01-01

Two physical experiments were developed to better define the thermal interaction of wetland water and the underlying soil layer. This information is important to numerical models of flow and heat transport that have been developed to support biological studies in the South Florida coastal wetland areas. The experimental apparatus consists of two 1.32. m diameter by 0.99. m tall, trailer-mounted, well-insulated tanks filled with soil and water. A peat-sand-soil mixture was used to represent the wetland soil, and artificial plants were used as a surrogate for emergent wetland vegetation based on size and density observed in the field. The tanks are instrumented with thermocouples to measure vertical and horizontal temperature variations and were placed in an outdoor environment subject to solar radiation, wind, and other factors affecting the heat transfer. Instruments also measure solar radiation, relative humidity, and wind speed.Tests indicate that heat transfer through the sides and bottoms of the tanks is negligible, so the experiments represent vertical heat transfer effects only. The temperature fluctuations measured in the vertical profile through the soil and water are used to calibrate a one-dimensional heat-transport model. The model was used to calculate the thermal conductivity of the soil. Additionally, the model was used to calculate the total heat stored in the soil. This information was then used in a lumped parameter model to calculate an effective depth of soil which provides the appropriate heat storage to be combined with the heat storage in the water column. An effective depth, in the model, of 5.1. cm of wetland soil represents the heat storage needed to match the data taken in the tank containing 55.9. cm of peat/sand/soil mix. The artificial low-density laboratory sawgrass reduced the solar energy absorbed by the 35.6. cm of water and 55.9. cm of soil at midday by less than 5%. The maximum heat transfer into the underlying peat-sand-soil mix lags behind maximum solar radiation by approximately 2. h. A slightly longer temperature lag was observed between the maximum solar radiation and maximum water temperature both with and without soil. ?? 2012 Elsevier B.V.

Predicting organic matter, nitrogen, and phosphorus concentrations in runoff from peat extraction sites using partial least squares regression

NASA Astrophysics Data System (ADS)

Tuukkanen, T.; Marttila, H.; Kløve, B.

2017-07-01

Organic matter and nutrient export from drained peatlands is affected by complex hydrological and biogeochemical interactions. Here partial least squares regression (PLSR) was used to relate various soil and catchment characteristics to variations in chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) concentrations in runoff. Peat core samples and water quality data were collected from 15 peat extraction sites in Finland. PLSR models constructed by cross-validation and variable selection routines predicted 92, 88, and 95% of the variation in mean COD, TN, and TP concentration in runoff, respectively. The results showed that variations in COD were mainly related to net production (temperature and water-extractable dissolved organic carbon (DOC)), hydrology (topographical relief), and solubility of dissolved organic matter (peat sulfur (S) and calcium (Ca) concentrations). Negative correlations for peat S and runoff COD indicated that acidity from oxidation of organic S stored in peat may be an important mechanism suppressing organic matter leaching. Moreover, runoff COD was associated with peat aluminum (Al), P, and sodium (Na) concentrations. Hydrological controls on TN and COD were similar (i.e., related to topography), whereas degree of humification, bulk density, and water-extractable COD and Al provided additional explanations for TN concentration. Variations in runoff TP concentration were attributed to erosion of particulate P, as indicated by a positive correlation with suspended sediment concentration (SSC), and factors associated with metal-humic complexation and P adsorption (peat Al, water-extractable P, and water-extractable iron (Fe)).

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...

CH4 production via CO2 reduction in a temperate bog - A source of (C-13)-depleted CH4

NASA Technical Reports Server (NTRS)

Lansdown, J. M.; Quay, P. D.; King, S. L.

1992-01-01

The paper reports measurements, taken over two annual cycles, of the flux and delta(C-13) of CH4 released from an acidic peat bog located in the foothills of the Cascade Range in Washington state, U.S. Measurements of the rate of aceticlastic methanogenesis and CO2 reduction in peat soil, using (C-14)-labeled acetate and sodium bicarbonate, show that acetate was not an important CH4 precursor and that CO2 reduction could account for all of the CH4 production. The in situ kinetic isotope effect for CO2 reduction, calculated using the delta-(C-13) of soil water CO2 and CH4 flux, was 0.932 +/- 0.007.

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 insoluble material (AIM) and AIM/N were significant predictors of decomposition. However, when limited to individual peatland features or bryophyte species, soluble proximate fractions were better predictors of organic matter decay. This suggests that decomposition within single litter or peat types is controlled by the size of relatively small, labile carbon pools. As peatlands store the majority of soil carbon in the boreal forest, the influences of peat quality on carbon storage and turnover should be considered in understanding the fate of carbon in northern ecosystems.

In Place Soil Treatments for Prevention of Explosives Contamination

DTIC Science & Technology

2010-01-01

gallon plastic drums. Treatment Layer Preparation The PMSO mixture was prepared in a ratio of peat moss and crude soybean oil of 1:1 (w:w). The...PMSO was prepared in batches using a small tow-behind plastic drum gas cement mixer (9 cu. ft capacity). Peat moss bags were weighed, and then emptied...wrap (or other applicable shipping materials) and shipped in plastic coolers by a commercial carrier priority overnight in ice. Holding Times

Fe(III)-EDDHA and -EDDHMA sorption on Ca-montmorillonite, ferrihydrite, and peat.

PubMed

Hernández-Apaolaza, L; Lucena, J J

2001-11-01

The effectiveness of Fe chelates as Fe sources and carriers in soil can be severely limited by the adsorption of Fe chelates or chelating agents in the solid phase. To study this phenomenon, well-characterized peat, Ca-montmorillonite, and ferrihydrite were used as model compounds, and the adsorption of Fe-EDDHA and Fe-EDDHMA chelates were studied. Sorption isotherms for the meso and racemic isomers of these chelates on the soil materials are described. The variability of sorption with pH in peat and ferrihydrite was also determined because both have variable surface charge at different pH values. In montmorillonite, at low concentrations, the retention of Fe from the Fe-EDDHMA chelate is greater than the one of the Fe-EDDHA chelate. As well as the concentration increased, the inverse situation occurs. The behavior of both meso and racemic isomers of chelates in contact with Ca-montmorillonite is similar. The Fe-meso-EDDHA isomer was highly adsorbed on ferrihydrite, but the racemic isomer is not significantly retained by this oxide. For Fe-EDDHMA isomers, the racemic isomer was more retained by the oxide, but a small sorption of the racemic isomer was also observed. Results suggest that Fe-EDDHA chelates were more retained in peat than Fe-EDDHMA chelates. The most retained isomer of Fe-EDDHA was the meso isomer. For Fe-EDDHMA, the adsorption was very low for both racemic and meso isomers.

Gaseous mercury fluxes in peatlands and the potential influence of climate change

NASA Astrophysics Data System (ADS)

Haynes, Kristine M.; Kane, Evan S.; Potvin, Lynette; Lilleskov, Erik A.; Kolka, Randall K.; Mitchell, Carl P. J.

2017-04-01

Climate change has the potential to significantly impact the stability of large stocks of mercury (Hg) stored in peatland systems due to increasing temperatures, altered water table regimes and subsequent shifts in vascular plant communities. However, the Hg exchange dynamics between the atmosphere and peatlands are not well understood. At the PEATcosm Mesocosm Facility in Houghton, Michigan, total gaseous Hg (TGM) fluxes were monitored in a subset of 1-m3 peat monoliths with altered water table positions (high and low) and vascular plant functional groups (sedge only, Ericaceae only or unmanipulated control) above the Sphagnum moss layer. At the SPRUCE bog in north-central Minnesota, TGM fluxes were measured from plots subjected to deep peat soil warming (up to +9 °C above ambient at a depth of 2 m). At PEATcosm, the strongest depositional trend was observed with the Low WT - sedge only treatment mesocosms with a mean TGM flux of -73.7 ± 6.3 ng m-2 d-1, likely due to shuttling of Hg to the peat at depth by aerenchymous tissues. The highest total leaf surface and tissue Hg concentrations were observed with the Ericaceae shrubs. A negative correlation between TGM flux and Ericaceae total leaf surface area suggests an influence of shrubs in controlling Hg exchange through stomatal uptake, surface sorption and potentially, peat shading. Surface peat total Hg concentrations are highest in treatments with greatest deposition suggesting deposition controls Hg accumulation in surface peat. Fluxes in the SPRUCE plots ranged from -45.9 ± 93.8 ng m-2 d-1 prior to the implementation of the deep warming treatments to -1.41 ± 27.1 ng m-2 d-1 once warming targets were achieved at depth and +10.2 ± 44.6 ng m-2 d-1 following prolonged deep soil warming. While these intervals did not differ significantly, a significant positive increase in the slope of the regression between flux and surface temperature was observed across the pre-treatment and warming periods. Shifts in vascular vegetation cover and peat warming as a result of climate change may significantly affect the dynamics of TGM fluxes between peatlands and the atmosphere.

Quantifying spatial variability of depth of peat burn in wetlands in relation to antecedent characteristics using field data, multi-temporal and multi-spectral LiDAR

NASA Astrophysics Data System (ADS)

Chasmer, L.; Flade, L.; Virk, R.; Montgomery, J. S.; Hopkinson, C.; Thompson, D. K.; Petrone, R. M.; Devito, K.

2017-12-01

Landscape changes in the hydrological characteristics of wetlands in some parts of the Boreal region of Canada are occurring as a result of climate-induced feedbacks and anthropogenic disturbance. Wetlands are largely resilient to wildfire, however, natural, climatic and anthropogenic disturbances can change surface water regimes and predispose wetlands to greater depth of peat burn. Over broad areas, peat loss contributes to significant pollution emissions, which can affect community health. In this study, we a) quantify depth of peat burn and relationships to antecedent conditions (species type, topography, surficial geology) within three classified wetlands found in the Boreal Plains ecoregion of western Canada; and b) examine the impacts of wildfire on post-fire ground surface energy balance to determine how peat loss might affect local hydro-climatology and surface water feedbacks. High-resolution optical imagery, pre- and post-burn multi-spectral Light Detection And Ranging (LiDAR), airborne thermal infrared imagery, and field validation data products are integrated to identify multiple complex interactions within the study wetlands. LiDAR-derived depth of peat burn is within 1 cm (average) compared with measured (RMSE = 9 cm over the control surface), demonstrating the utility of LiDAR with high point return density. Depth of burn also correlates strongly with variations in Normalised Burn Ratio (NBR) determined for ground surfaces only. Antecedent conditions including topographic position, soil moisture, soil type and wetland species also have complex interactions with depth of peat loss within wetlands observed in other studies. However, while field measurements are important for validation and understanding eco-hydrological processes, results from remote sensing are spatially continuous. Temporal LiDAR data illustrate the full range of variability in depth of burn and wetland characteristics following fire. Finally, measurements of instantaneous surface temperature indicate that the temperatures of burned wetlands are significantly warmer by up to 10oC compared to non-burned wetlands, altering locally variable sensible vs. latent energy exchanges and implications for further post-fire evaporative losses.

Saturated and unsaturated salt transport in peat from a constructed fen

NASA Astrophysics Data System (ADS)

Simhayov, Reuven B.; Weber, Tobias K. D.; Price, Jonathan S.

2018-02-01

The underlying processes governing solute transport in peat from an experimentally constructed fen peatland were analyzed by performing saturated and unsaturated solute breakthrough experiments using Na+ and Cl- as reactive and non-reactive solutes, respectively. We tested the performance of three solute transport models, including the classical equilibrium convection-dispersion equation (CDE), a chemical non-equilibrium one-site adsorption model (OSA) and a model to account for physical non-equilibrium, the mobile-immobile (MIM) phases. The selection was motivated by the fact that the applicability of the MIM in peat soils finds a wide consensus. However, results from inverse modeling and a robust statistical evaluation of this peat provide evidence that the measured breakthrough of the conservative tracer, Cl-, could be simulated well using the CDE. Furthermore, the very high Damköhler number (which approaches infinity) suggests instantaneous equilibration between the mobile and immobile phases underscoring the redundancy of the MIM approach for this particular peat. Scanning electron microscope images of the peat show the typical multi-pore size distribution structures have been homogenized sufficiently by decomposition, such that physical non-equilibrium solute transport no longer governs the transport process. This result is corroborated by the fact the soil hydraulic properties were adequately described using a unimodal van Genuchten-Mualem model between saturation and a pressure head of ˜ -1000 cm of water. Hence, MIM was not the most suitable choice, and the long tailing of the Na+ breakthrough curve was caused by chemical non-equilibrium. Successful description was possible using the OSA model. To test our results for the unsaturated case, we conducted an unsaturated steady-state evaporation experiment to drive Na+ and Cl- transport. Using the parameterized transport models from the saturated experiments, we could numerically simulate the unsaturated transport using Hydrus-1-D. The simulation showed a good prediction of observed values, confirming the suitability of the parameters for use in a slightly unsaturated transport simulation. The findings improve the understanding of solute redistribution in the constructed fen and imply that MIM should not be automatically assumed for solute transport in peat but rather should be evidence based.

Identity of active methanotrophs in landfill cover soil as revealed by DNA-stable isotope probing.

PubMed

Cébron, Aurélie; Bodrossy, Levente; Chen, Yin; Singer, Andrew C; Thompson, Ian P; Prosser, James I; Murrell, J Colin

2007-10-01

A considerable amount of methane produced during decomposition of landfill waste can be oxidized in landfill cover soil by methane-oxidizing bacteria (methanotrophs) thus reducing greenhouse gas emissions to the atmosphere. The identity of active methanotrophs in Roscommon landfill cover soil, a slightly acidic peat soil, was assessed by DNA-stable isotope probing (SIP). Landfill cover soil slurries were incubated with (13)C-labelled methane and under either nutrient-rich nitrate mineral salt medium or water. The identity of active methanotrophs was revealed by analysis of (13)C-labelled DNA fractions. The diversity of functional genes (pmoA and mmoX) and 16S rRNA genes was analyzed using clone libraries, microarrays and denaturing gradient gel electrophoresis. 16S rRNA gene analysis revealed that the cover soil was mainly dominated by Type II methanotrophs closely related to the genera Methylocella and Methylocapsa and to Methylocystis species. These results were supported by analysis of mmoX genes in (13)C-DNA. Analysis of pmoA gene diversity indicated that a significant proportion of active bacteria were also closely related to the Type I methanotrophs, Methylobacter and Methylomonas species. Environmental conditions in the slightly acidic peat soil from Roscommon landfill cover allow establishment of both Type I and Type II methanotrophs.

In-situ molecular-level elucidation of organofluorine binding sites in a whole peat soil.

PubMed

Longstaffe, James G; Courtier-Murias, Denis; Soong, Ronald; Simpson, Myrna J; Maas, Werner E; Fey, Michael; Hutchins, Howard; Krishnamurthy, Sridevi; Struppe, Jochem; Alaee, Mehran; Kumar, Rajeev; Monette, Martine; Stronks, Henry J; Simpson, André J

2012-10-02

The chemical nature of xenobiotic binding sites in soils is of vital importance to environmental biogeochemistry. Interactions between xenobiotics and the naturally occurring organic constituents of soils are strongly correlated to environmental persistence, bioaccessibility, and ecotoxicity. Nevertheless, because of the complex structural and chemical heterogeneity of soils, studies of these interactions are most commonly performed indirectly, using correlative methods, fractionation, or chemical modification. Here we identify the organic components of an unmodified peat soil where some organofluorine xenobiotic compounds interact using direct molecular-level methods. Using (19)F→(1)H cross-polarization magic angle spinning (CP-MAS) nuclear magnetic resonance (NMR) spectroscopy, the (19)F nuclei of organofluorine compounds are used to induce observable transverse magnetization in the (1)H nuclei of organic components of the soil with which they interact after sorption. The observed (19)F→(1)H CP-MAS spectra and dynamics are compared to those produced using model soil organic compounds, lignin and albumin. It is found that lignin-like components can account for the interactions observed in this soil for heptafluoronaphthol (HFNap) while protein structures can account for the interactions observed for perfluorooctanoic acid (PFOA). This study employs novel comprehensive multi-phase (CMP) NMR technology that permits the application of solution-, gel-, and solid-state NMR experiments on intact soil samples in their swollen state.

Mangrove peat analysis and reconstruction of vegetation history at the Pelican Cays, Belize

USGS Publications Warehouse

McKee, K.L.; Faulkner, P.L.

2000-01-01

The substrate beneath mangrove forests in the Pelican Cays complex is predominately peat composed mainly of mangrove roots. Leaves and wood account for less than 20% of the peat mass. At Cat Cay, the depth of the peat ranges from 0.2 m along the shoreline to 1.65 m in the island center, indicating that the island has expanded horizontally as well as vertically through below-ground, biogenic processes. Mangrove roots thus play a critical role in the soil formation, vertical accretion, and stability of these mangrove cays. The species composition of fossil roots changes markedly with depth: Rhizophora mangle (red mangrove) was the initial colonizer on a coral base, followed by Avicennia germinans (black mangrove), which increased in abundance and expanded radially from the center of the island. The center of the Avicennia stand ultimately died, leaving an unvegetated, shallow pond. The peat thus retains a record of mangrove development, succession, and deterioration in response to sea-level change and concomitant hydroedaphic conditions controlling dispersal, establishment, growth, and mortality of mangroves on oceanic islands in Belize.

Effect of climate changes in the holocene on the distribution of humic substances in the profile of forest-tundra peat mounds

NASA Astrophysics Data System (ADS)

Vasilevich, R. S.; Beznosikov, V. A.

2017-11-01

The molecular composition of humic substances in permafrost peatlands of the forest-tundra zone in northeastern European Russia has been characterized for the first time on the basis of systematic studies. Changes in the molar x(H): x(C) ratio along the peat profiles have been revealed, which is due to the activation of cryogenic processes in the upper part of the seasonally thawing layer, the natural selection of condensed humic molecules, and the botanical composition and degree of degradation of peat, which reflect the climatic features of the area in the Holocene. Dry-peat soils of mounds are worse heated during the summer period because of the buffering effect of moss litter, which results in a lower degree of condensation of humic and fulvic acid molecules in the peat horizons down to the permafrost table. Transformation of quantitative and qualitative parameters of specific organic compounds occurs at the permafrost boundary of peatlands, which can serve as an indicator of recent climate changes in high latitudes.

Analysis of ecological factors limiting the destruction of high-moor peat

NASA Astrophysics Data System (ADS)

Dobrovol'skaya, T. G.; Golovchenko, A. V.; Zvyagintsev, D. G.

2014-03-01

This review presents an analysis of literature data and original studies by the authors aimed at revealing the factors inhibiting the destruction of high-moor (oligotrophic) peat. Each of the ecological factors that prevent the decomposition of the high-moor peat by different groups of microorganisms is considered. The acid reaction, low temperatures, and lack of nutrients were found not to be the primary factors inhibiting the destruction of the peat. The limited content of oxygen in the peatbogs leads to a drastic decrease in the number of mycelial microorganisms and a reduction of the activity of hydrolytic and oxidizing enzymes. The main factor inhibiting the decomposition of sphagnum is its mechanical and chemical stability, since animals crushing sphagnum are absent in the soil, and this moss has polysaccharides of special composition. The toxicity of phenol compounds, which is manifested under the aerobic conditions, prevents the activity of all the hydrolytic enzymes. This is the main reason for the slow decomposition of sphagnum peat and the long-term preservation of the residues of bodies and food in high-moor peatlands.

Climatic triggers for peatland initiation

NASA Astrophysics Data System (ADS)

Morris, Paul J.; Swindles, Graeme T.; Valdes, Paul J.; Ivanovic, Ruza F.; Gregoire, Lauren J.; Smith, Mark W.; Tarasov, Lev; Haywood, Alan M.; Bacon, Karen L.

2017-04-01

Peatlands are carbon-dense wetlands characterised by waterlogged, organic-rich soils. Modern-day peatlands have formed mainly since the Last Glacial Maximum (LGM), and despite covering only 3 % of the Earth's land surface are thought to store more than a third of all global soil carbon in the form of poorly decomposed plant detritus. Concern exists that this globally important carbon store may be vulnerable to near-future warming and changes in precipitation patterns, although the links between peatland development and climate are contested. The climatic and other environmental conditions that facilitate the initiation of peat are particularly poorly understood. We present the results of a novel, global study into the climate space of peat initiation since the LGM. We compiled a catalogue of radiocarbon dates of peat initiation from 942 sites that span a range of latitudes and biomes. We used the locations and ages of these peatlands to interrogate downscaled climate hindcasts at 500-yr intervals from a coupled atmosphere-ocean-vegetation general circulation model, HadCM3. This powerful combination of modelling and observational data provides a globally-consistent, temporally-extensive estimate of the climate spaces of peat initiation. In particular, it allows us to identify local and regional climatic changes that may have acted as triggers for peat formation. Peatlands in mid- and high-latitudes of both hemispheres, particularly in maritime locations, developed shortly after local increases in the time integral of growing season temperatures, and were seemingly not influenced by rainfall regime. Peat initiation at such sites appears to have been stimulated by temperature-driven increases in plant productivity in cold, postglacial landscapes, and was not water limited. The exception is the large peatland complex of the Western Siberian Lowlands, which was not glaciated during the last glacial period, and which appears to have been prompted instead by a strong increase in effective precipitation, leading to extensive paludification. Peat initiation in the tropics appears only weakly related to climate, suggesting that other environmental factors such as drainage network evolution and relative sea level change due to tectonic subsidence were more important there. Our model-data fusion also provides valuable context for projected future climate change. In particular, projected temperature increases for the 21st Century, even under modest emissions scenarios, far exceed those experienced by current peatland locations during the course of peat development, and therefore seem likely to exceed these ecosystems' capacities for resistance and resilience.

Age, extent and carbon storage of the central Congo Basin peatland complex.

PubMed

Dargie, Greta C; Lewis, Simon L; Lawson, Ian T; Mitchard, Edward T A; Page, Susan E; Bocko, Yannick E; Ifo, Suspense A

2017-02-02

Peatlands are carbon-rich ecosystems that cover just three per cent of Earth's land surface, but store one-third of soil carbon. Peat soils are formed by the build-up of partially decomposed organic matter under waterlogged anoxic conditions. Most peat is found in cool climatic regions where unimpeded decomposition is slower, but deposits are also found under some tropical swamp forests. Here we present field measurements from one of the world's most extensive regions of swamp forest, the Cuvette Centrale depression in the central Congo Basin. We find extensive peat deposits beneath the swamp forest vegetation (peat defined as material with an organic matter content of at least 65 per cent to a depth of at least 0.3 metres). Radiocarbon dates indicate that peat began accumulating from about 10,600 years ago, coincident with the onset of more humid conditions in central Africa at the beginning of the Holocene. The peatlands occupy large interfluvial basins, and seem to be largely rain-fed and ombrotrophic-like (of low nutrient status) systems. Although the peat layer is relatively shallow (with a maximum depth of 5.9 metres and a median depth of 2.0 metres), by combining in situ and remotely sensed data, we estimate the area of peat to be approximately 145,500 square kilometres (95 per cent confidence interval of 131,900-156,400 square kilometres), making the Cuvette Centrale the most extensive peatland complex in the tropics. This area is more than five times the maximum possible area reported for the Congo Basin in a recent synthesis of pantropical peat extent. We estimate that the peatlands store approximately 30.6 petagrams (30.6 × 10 15  grams) of carbon belowground (95 per cent confidence interval of 6.3-46.8 petagrams of carbon)-a quantity that is similar to the above-ground carbon stocks of the tropical forests of the entire Congo Basin. Our result for the Cuvette Centrale increases the best estimate of global tropical peatland carbon stocks by 36 per cent, to 104.7 petagrams of carbon (minimum estimate of 69.6 petagrams of carbon; maximum estimate of 129.8 petagrams of carbon). This stored carbon is vulnerable to land-use change and any future reduction in precipitation.

Trace metal mobilization by organic soil amendments: insights gained from analyses of solid and solution phase complexation of cadmium, nickel and zinc.

PubMed

Welikala, Dharshika; Hucker, Cameron; Hartland, Adam; Robinson, Brett H; Lehto, Niklas J

2018-05-01

The accumulation of Cd in soils worldwide has increased the demand for methods to reduce the metal's plant bioavailability. Organic matter rich soil amendments have been shown to be effective in achieving this. However, it is not known how long these amendments can retain the Cd, and whether dissolved organic matter (DOM) released from them can enhance the metal's mobility in the environment. In this study we sought to test the Cd binding capacity of various organic soil amendments, and evaluate differences in characteristics of the DOM released to see if they can explain the lability of the Cd-DOM complexes. We collected ten organic soil amendments from around New Zealand: five different composts, biosolids from two sources, two types of peat and spent coffee grounds. We characterised the amendments' elemental composition and their ability to bind the Cd. We then selected two composts and two peats for further tests, where we measured the sorption of Ni or Zn by the amendments. We analysed the quality of the extracted DOM from the four amendments using 3D Excitation Emission Matrix analysis, and tested the lability of the metal-DOM complexes using an adapted diffusive gradients in thin-films (DGT) method. We found that composts bound the most Cd and that the emergent Cd-DOM complexes were less labile than those from the peats. Ni-DOM complexes were the least labile. The aromaticity of the extracted DOM appears to be an important factor in determining the lability of Ni complexes, but less so for Zn and Cd. Copyright © 2018 Elsevier Ltd. All rights reserved.

Surface covering of downed logs: drivers of a neglected process in dead wood ecology.

PubMed

Dynesius, Mats; Gibb, Heloise; Hjältén, Joakim

2010-10-07

Many species use coarse woody debris (CWD) and are disadvantaged by the forestry-induced loss of this resource. A neglected process affecting CWD is the covering of the surfaces of downed logs caused by sinking into the ground (increasing soil contact, mostly covering the underside of the log), and dense overgrowth by ground vegetation. Such cover is likely to profoundly influence the quality and accessibility of CWD for wood-inhabiting organisms, but the factors affecting covering are largely unknown. In a five-year experiment we determined predictors of covering rate of fresh logs in boreal forests and clear-cuts. Logs with branches were little covered because they had low longitudinal ground contact. For branchless logs, longitudinal ground contact was most strongly related to estimated peat depth (positive relation). The strongest predictor for total cover of branchless logs was longitudinal ground contact. To evaluate the effect on cover of factors other than longitudinal ground contact, we separately analyzed data from only those log sections that were in contact with the ground. Four factors were prominent predictors of percentage cover of such log sections: estimated peat depth, canopy shade (both increasing cover), potential solar radiation calculated from slope and slope aspect, and diameter of the log (both reducing cover). Peat increased cover directly through its low resistance, which allowed logs to sink and soil contact to increase. High moisture and low temperatures in pole-ward facing slopes and under a canopy favor peat formation through lowered decomposition and enhanced growth of peat-forming mosses, which also proved to rapidly overgrow logs. We found that in some boreal forests, peat and fast-growing mosses can rapidly cover logs lying on the ground. When actively introducing CWD for conservation purposes, we recommend that such rapid covering is avoided, thereby most likely improving the CWD's longevity as habitat for many species.

Thermodynamic constrains on the flux of organic matter through a peatland ecosystem

NASA Astrophysics Data System (ADS)

Worrall, Fred; Moody, Catherine; Clay, Gareth; Kettridge, Nick; Burt, Tim

2017-04-01

The transformations and transitions of organic matter into, through and out of a peatland ecosystem must obey the 2nd law of thermodynamics. Beer and Blodau (Geochimica Cosmochimica Acta, 2007, 71, 12, 2989-3002) showed that the evolution of CH4 in peatlands was constrained by equilibrium occurring at depth in the peat as the pore water became a closed system. However, that study did not consider the transition in the solid components of the organic matter flux through the entire ecosystem. For this study, organic matter samples were taken from each organic matter reservoir and fluvial transfer pathway and analysed the samples by elemental analysis and bomb calorimetry. The samples analysed were: above- and below-ground biomass, heather, mosses, sedges, plant litter layer, peat soil, 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, and plant protein. It was possible to calculate ∆H_f^OM ∆S_f^OM and ∆G_f^OM for each of the samples and standards. By assuming that each thermodynamic property can be expressed per g C and that any increase in ∆G_f^OM can be balanced by the production of CO2, DOM or CH4 then it is possible to predict the consequences of the fixation of 1 g of carbon in a peatland soil. The value of ∆G_f^OMincreases from glucose to components of the biomass: 1g of C fixed as glucose by photosynthesis would result in 0.68 g C as biomass and 0.32 g C as CO2. The transition from biomass to litter could occur spontaneously but the transition from surface to 1m depth in the peat profile would release 0.18 g C as CO2 per 1 g of carbon entering the peat profile. Therefore, for every 1 g of carbon fixed from photosynthesis then 0.44g of C would be released as CO2 and 0.54 g C would be present at 1 m depth. Alternatively, if DOM only were released in transition down the peat profile then for every 1 g of carbon fixed by photosynthesis 0.32 g C would be released as CO2 and 0.22 g C would be lost as DOM and leaving 0.46 g C as residual peat at 1m depth. If the variation in ∆G_f^OM of the DOM were considered then for every 1 g of C produced as DOM then between 0 and 0.57g C would be lost as CO2. At median value of DOM loss then for every 1g of carbon fixed as photosynthesis 0.39 g C would be lost as CO2 and 0.15 g lost as DOM with 0.46 g C as residual peat. Alternatively, if CH4 only were released down the soil profile then no organic matter would be left in the peat profile, i.e. CH4 is not an efficient method of transferring Gibbs free energy. The measured carbon budget for this catchment is that 1 g C fixed as photosynthesis resulted in 0.42 g C as CO2; 0.29 g C as DOM; 0.04 g C as CH4 and 0.24 g C as residual peat at 1m depth.

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

NASA Astrophysics Data System (ADS)

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

2013-04-01

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

Can we Ecohydrologically Rehabilitate Disturbed Peatlands? From "Wetlands of Mass Decomposition" to "Yes We Can"

NASA Astrophysics Data System (ADS)

Waddington, J. M.; Cagampan, J.; Lucchese, M.; Thompson, D. K.; Duval, T. P.

2009-05-01

The natural carbon storage function of peatland ecosystems can be severely affected by human and natural disturbances such as drainage, peat extraction, drought and wildfire. Cutover peatands, for example, become a large and persistent source of atmospheric CO2 following peat extraction. The recovery (rehabilitation, re- establishment, restoration) of disturbed peatlands to a net carbon sink depends to a large extent on the rate of recovery of the surface peat layer referred to as the acrotelm. The acrotelm serves to stabilize water table variation providing ideal conditions for vegetation re-establishment, particularly peat forming Sphagnum moss. Here we present results from several ecosystem-scale field experiments where we examined the change in hydrophysical properties of peat following peat extraction and subsequent restoration and discuss how this affects peatland-atmosphere CO2. We found that moisture retention properties of a new peat layer at a restored peatland were distinct from near- by natural and naturally regenerated sites. Despite considerable biomass accumulation and increase in peat thickness, the new peat layer differed with respect to its moisture retention properties, an indication that factors other than growth have an impact on the restoration of the returning moss layer. Similarly in an acrotelm transplant experiment we determined that the restored peatland experienced high variability in volumetric moisture content (VMC) in the capitula zone (upper 2 cm) where large diurnal changes in VMC (~30%) were observed, suggesting possible disturbance to the peat matrix structure during the extraction-restoration process. However, soil - water retention analysis and physical peat properties (porosity and bulk density) suggest that no significant differences existed between the natural and restored sites. A simple hydrologic model demonstrated that the new peat layer will become an acrotelm in ~20 years when ~20 cm of peat has accumulated, an approach which may aid in designing a long-term sampling strategy for assessing the long- term effects of restoration of disturbed peatlands on peatland hydrology and ecology. Applications of these findings to a new research collaboration on the effects of wildfire on peatland ecohydrology will be discussed.

Mitigating climate change through the understanding of Nitrous Oxide (N2O) consumption processes in peat lands

NASA Astrophysics Data System (ADS)

Akrami, N.; Barker, X. Z.; Horwath, W. R.

2017-12-01

Nitrous Oxide (N2O) with global warming potential of 298 over a 100-year horizon is one of the most potent green house gases. In the United States, agriculture share to N2O emissions is over 70%. Peat lands, however, are being considered as both sources and sinks of greenhouse gases. N2O emissions are a product of both production and consumption processes. However, there is still a lack of understanding of N2O consumption processes in soils. In this work, the potential of re-wetted peat lands planted to rice in Sacramento-San Joaquin Delta, California, to act as a potential sink for N2O is being evaluated. Four peat land soils with 1%, 5%, 11% and 23% of organic carbon have been anaerobically incubated with different water contents (15%, 30%, 50%, 75% and 100% of their water holding capacity). 15N-N2O gas has been injected to the headspace of experiment jars and the production and consumption rate of 15N-N2O, 15N-N2 and production rate of Carbon Dioxide (CO2) and Methane (CH4) along with dissolved Nitrate (NO3-), Nitrite (NO2-), Ammonium (NH4+), Iron (II) and Iron (III) concentration has been quantified. Our results show promising N2O consumption rates under high carbon content and relatively high water content treatments. This research introduces organic carbon and water content as two major criteria in N2O consumption processes in peat lands that make it a potential hotspot for climate changes mitigation through adopting effective management practices to decrease greenhouse gas emissions.

Smouldering Combustion of Soil Organic Matter: Inverse Modelling of the Thermal and Oxidative Degradation Kinetics

NASA Astrophysics Data System (ADS)

Huang, Xinyan; Rein, Guillermo

2013-04-01

Smouldering combustion of soil organic matter (SOM) such as peatlands leads to the largest fires on Earth and posses a possible positive feedback mechanism to climate change. In this work, a kinetic model, including 3-step chemical reactions and 1-step water evaporation is proposed to describe drying, pyrolysis and oxidation behaviour of peat. Peat is chosen as the most important type of SOM susceptible to smoudering, and a Chinese boreal peat sample is selected from the literature. A lumped model of mass loss based on four Arrhenius-type reactions is developed to predict its thermal and oxidative degradation under a range of heating rates. A genetic algorithm is used to solve the inverse problem, and find a group of kinetic and stoichiometric parameters for this peat that provides the best match to the thermogravimetric (TG) data from literature. A multi-objective fitness function is defined using the measurements of both mass loss and mass-loss rate in inert and normal atmospheres under a range of heating rates. Piece-wise optimization is conducted to separate the low temperature drying (<450 K) from the higher temperature pyrolysis and oxidation reaction (>450 K). Modelling results shows the proposed 3-step chemistry is the unique simplest scheme to satisfy all given TG data of this particular peat type. Afterward, this kinetic model and its kinetic parameters are incorporated into a simple one-dimensional species model to study the relative position of each reaction inside a smoulder front. Computational results show that the species model agrees with experimental observations. This is the first time that the smouldering kinetics of SOM is explained and predicted, thus helping to understanding this important natural and widespread phenomenon.

The Effects of Light Intensity, Casing Layers, and Layering Styles on Royal Sun Medicinal Mushroom, Agaricus brasiliensis (Higher Basidiomycetes) Cultivation in Turkey.

PubMed

Adanacioglu, Neşe; Boztok, Kaya; Akdeniz, Ramazan Cengiz

2015-01-01

The aim of this research is to evaluate the effects of light intensity, casing layers, and layering styles on the production of the culinary-medicinal mushroom Agaricus brasiliensis in Turkey. The experiments were designed in split-split plots and replicated twice. Three different light intensities-I1, 350 lux; I2, 450 lux; and I3, 750 lux-were used in main plots as environmental factors. A mixture of 4 different casing layers- peat (100%), peat-perlite (75%:25%), peat-clinoptilolite (75%:25%), and peat-perlite-clinoptilolite (60%:20%:20%)-were used at split plots and at split plots. S1, a flat, 3-cm casing layer; S2, a flat, 5-cm casing layer; and S3, casing soil ridges 10 cm wide × 4 cm high, 10 cm apart, were deposited on top of 1-cm overall soil casing layers. At the end of the harvest phase, the total yield was estimated per 100 kg of substrate. Biological efficiency (percentage) was determined from the fresh weight of the mushrooms and the dry weight of the compost at the end of the harvesting period. The highest total yield (7.2 kg/100 kg compost) and biological efficiency (27.63%) were achieved from I2 × peat-perlite-clinoptilolite × S2 treatment. Influence of light intensity, casing layer, layering style, and their interaction in treatments with color values (L*, a*, b*, chroma*, and hue*) also were examined. It has been shown that within color values, chroma* (saturation) values of mushroom caps were affected by light intensity, casing layer, and layering style treatments and light intensity × casing layer treatments and the brightness of mushroom caps tended to increase as light intensity increased.

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.

The decomposition of vegetation and soil in marginal peat-forming landscapes: climate simulations to quantify gaseous and dissolved carbon fluxes and the effects on peat accumulation and drinking water treatment

NASA Astrophysics Data System (ADS)

Ritson, J.; Bell, M.; Clark, J. M.; Graham, N.; Templeton, M.; Brazier, R.; Verhoef, A.; Freeman, C.

2013-12-01

Peatlands in the UK represent a large proportion of the soil carbon store, however there is concern that some systems may be switching from sinks to sources of carbon. The accumulation of organic material in peatlands results from the slow rates of decomposition typically occurring in these regions. Climate change may lead to faster decomposition which, if not matched by an equivalent increase in net primary productivity and litter fall, may tip the balance between source and sink. Recent trends have seen a greater flux of dissolved organic matter (DOM) from peatlands to surface waters and a change in DOM character, presenting challenges to water treatment, for example in terms of increased production of disinfectant by-products (DBPs). Peat systems border a large proportion of reservoirs in the UK so uncertainty regarding DOM quantity and quality is a concern for water utilities. This study considered five peatland vegetation types (Sphagnum spp., Calluna vulgaris, Molinea caerulea, peat soil and mixed litter) collected from the Exmoor National Park, UK where it is hypothesised that peat formation may be strongly affected by future changes to climate. A factorial experiment design to simulate climate was used, considering vegetation type, temperature and rainfall amount using a current baseline and predictions from the UKCP09 model. Gaseous fluxes of carbon were monitored over a two month period to quantify the effect on carbon mineralisation rates while 13C NMR analysis was employed to track which classes of compounds decayed preferentially. The DOM collected was characterised using UV and fluorescence techniques before being subject to standard drinking water treatment processes (coagulation/flocculation followed by chlorination). The effect of the experimental factors on DOM amenability to removal and propensity to form DBPs was then considered, with both trihalomethane (THM) and haloacetonitrile (HAN) DBP classes monitored. Initial results have shown a statistically significant (Mann-Whitney U) difference in THM formation (p<0.05) as well as the amount of DOM produced and specific UV absorption at 254nm (p<0.01) between vegetation classes.

Isolation, characterization, and formulation of antagonistic bacteria for the management of seedlings damping-off and root rot disease of cucumber.

PubMed

Khabbaz, Salah Eddin; Abbasi, Pervaiz A

2014-01-01

Antagonistic bacteria are common soil inhabitants with potential to be developed into biofungicides for the management of seedling damping-off, root rot, and other soil-borne diseases of various crops. In this study, antagonistic bacteria were isolated from a commercial potato field and screened for their growth inhibition of fungal and oomycete pathogens in laboratory tests. The biocontrol potential of the 3 most effective antagonistic bacteria from the in vitro tests was evaluated against seedling damping-off and root rot of cucumber caused by Pythium ultimum. Based on phenotypic characteristics, biochemical tests, and sequence analysis of 16S-23S rDNA gene, the 3 antagonistic bacteria were identified as Pseudomonas fluorescens (isolate 9A-14), Pseudomonas sp. (isolate 8D-45), and Bacillus subtilis (isolate 8B-1). All 3 bacteria promoted plant growth and suppressed Pythium damping-off and root rot of cucumber seedlings in growth-room assays. Both pre- and post-planting application of these bacteria to an infested peat mix significantly increased plant fresh masses by 113%-184% and percentage of healthy seedlings by 100%-290%, and decreased damping-off and root rot severity by 27%-50%. The peat and talc formulations of these antagonistic bacteria applied as seed or amendment treatments to the infested peat mix effectively controlled Pythium damping-off and root rot of cucumber seedlings and enhanced plant growth. The survival of all 3 antagonistic bacteria in peat and talc formulations decreased over time at room temperature, but the populations remained above 10(8) CFU/g during the 180-day storage period. The peat formulation of a mixture of 3 bacteria was the best seed treatment, significantly increasing the plant fresh masses by 245% as compared with the Pythium control, and by 61.4% as compared with the noninfested control. This study suggests that the indigenous bacteria from agricultural soils can be developed and formulated as biofungicides for minimizing the early crop losses caused by seedling damping-off and root rot diseases.

Influence of pine bark particle size and pH on cation exchange capacity

USDA-ARS?s Scientific Manuscript database

Cation exchange capacity (CEC) describes the maximum quantity of cations a soil or substrate can hold while being exchangeable with the soil solution. While CEC has been studied for peat-based substrates, relatively little work has documented factors that affect CEC of pine bark substrates. The ob...

Growing media [Chapter 5

Treesearch

Douglass F. Jacobs; Thomas D. Landis; Tara Luna

2009-01-01

Selecting the proper growing medium is one of the most important considerations in nursery plant production. A growing medium can be defined as a substance through which roots grow and extract water and nutrients. In native plant nurseries, a growing medium can consist of native soil but is more commonly an "artificial soil" composed of materials such as peat...

Initial Response of the Nitrogen Cycle to Soil Warming and Elevated CO2 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 an...

7 CFR 319.37-8 - Growing media.

Code of Federal Regulations, 2013 CFR

2013-01-01

... shall be free of sand, soil, earth, and other growing media, except as provided in paragraph (b), (c..., coir, cork, glass wool, organic and inorganic fibers, peat, perlite, phenol formaldehyde, plastic... greenhouse must be free from sand and soil and must have screening with openings of not more than 0.6 mm (0.2...

7 CFR 319.37-8 - Growing media.

Code of Federal Regulations, 2014 CFR

2014-01-01

... shall be free of sand, soil, earth, and other growing media, except as provided in paragraph (b), (c..., coir, cork, glass wool, organic and inorganic fibers, peat, perlite, phenol formaldehyde, plastic... greenhouse must be free from sand and soil and must have screening with openings of not more than 0.6 mm (0.2...

7 CFR 319.37-8 - Growing media.

Code of Federal Regulations, 2012 CFR

2012-01-01

... shall be free of sand, soil, earth, and other growing media, except as provided in paragraph (b), (c..., coir, cork, glass wool, organic and inorganic fibers, peat, perlite, phenol formaldehyde, plastic... greenhouse must be free from sand and soil and must have screening with openings of not more than 0.6 mm (0.2...

Influence of different kind of peats on some physic-chemical properties, biochemical activity, the content of different forms of nitrogen and fractions of humic substances of The Great Vasyugan Mire

NASA Astrophysics Data System (ADS)

Inisheva, L. I.; Szajdak, L.

2009-04-01

Mires, or peatlands belong to the wetlands ecosystems where carbon is bounded in primary production and deposited as peat in water saturated, anoxic conditions. In those conditions, the rate of the supply of new organic matter has exceeded that the decomposition, resulting in carbon accumulation. Place of sampling belongs to an oligotrophic landscapes of the river Klyuch basin in spurs of Vasyugan mire. The catchment represents reference system for Bokchar swampy area (political district of Tomsk region). Landscape profile crosses main kinds of swampy biogeocoenosis (BGC) toward the mire center: paludal tall mixed forest, pine undershrub Sphagnum (high riam, trans-accumulative part of a profile, P2), pine-undershrub Sphagnum (low riam, transit part, P3), sedge-moss swamp (eluvial part, P5). The latter represents an eluvial part of a slope of watershed massif where it is accomplished discharge of excess, surface, soil-mire waters. The depth of peat deposit of sedge-moss swamp reaches 2,5m. To the depth of 0,6m there is a layer of Sphagnum raised bog peat, then it is a mesotrophic Scheuchzeria Sphagnum layer and at the bottom there is a thick layer of low-mire horsetail peat. The samples of peats were taken from two places (P2 and P3), both from the depth 0-75 cm of the great Vasyugan Mire. These materials represent (P2) Sphagnum fuscum peat (ash content ranged from 10.8 to 15.1%), but samples P3 belong to low-moor sedge peat (ash content ranged from 4.5-4.8%). The differences in water level, redox potential, pH, degree of degradation, bulk density, number of microorganisms, activity of enzymes, different kinds of nitrogen and humic substances were studied in two different peat soils characterized by different type of peat. In general in P2 the redox potential changed from 858 to /-140/ mV, higher activity of xanthine oxidase and peroxidase, different kinds of microorganisms (ammonifing bacteria and cellulose decomposing microorganisms) and different kinds of nitrogen (mineral, easily hydrolysable, hardly hydrolysable and non-hydrolyzable), bitumines, 3 fractions of humic acids and 3 fractions of fulvic acids were determined in the deep 0-25 cm than in 50-75 cm. The ratio HA/FA in the depth 0-25 cm was equal to from 1.87, but in the depth 50-75 cm was equal to 7.66. Contrary was observed for P3. For this peat with the increase of the deep of sampling the decrease of total nitrogen, activity of enzymes (xanthine oxidase and peroxidase) is connected with the changes of Fe+2/Fe+3 and lower difference of redox potential than in P2. The ratio HA/FA in the depth 0-25 cm was equal to 0.56, but in the depth 50-70 cm was equal to 0.84.

Use of Lightweight Cellular Mats to Reduce the Settlement of Structure on Soft Soil

NASA Astrophysics Data System (ADS)

Ganasan, R.; Lim, A. J. M. S.; Wijeyesekera, D. C.

2016-07-01

Construction of structures on soft soils gives rise to some difficulties in Malaysia and other country especially in settlement both in short and long term. The focus of this research is to minimize the differential and non-uniform settlement on peat soil with the use of an innovative cellular mat. The behaviour and performance of the lightweight geo-material (in block form) is critically investigated and in particular the use as a fill in embankment on soft ground. Hemic peat soil, sponge and innovative cellular mat will be used as the main material in this study. The monitoring in settlement behavior from this part of research will be done as laboratory testing only. The uneven settlement in this problem was uniquely monitored photographically using spot markers. In the end of the research, it is seen that the innovative cellular mat has reduce the excessive and differential settlement up to 50% compare to flexible and rigid foundations. This had improve the stiffness of soils as well as the porous contain in cellular structure which help in allowing water/moisture to flow through in or out thus resulting in prevent the condition of floating.

Reconciling Harvest Intensity and Plant Diversity in Boreal Ecosystems: Does Intensification Influence Understory Plant Diversity?

PubMed

Kershaw, H Maureen; Morris, Dave M; Fleming, Robert L; Luckai, Nancy J

2015-11-01

Overall demand for forest products in the boreal forest is increasing to supply growing bio-energy demands in addition to traditional forest products. As a result, there is a need to refine current forest policies to reconcile production and ecosystem function within the context of ecologically sustainable management. This study assessed understory plants' richness, evenness, and diversity in six harvested boreal black spruce-dominated stands situated on loam, sand, and peat site types 15 years after the application of four harvest treatments of increasing biomass removals. Treatments included uncut, stem-only harvest, full-tree harvest, and full-tree harvest + blading of O horizon. Following canopy removal, species richness and diversity (Shannon's and Simpson's indices) increased on all soil types. The more than doubling of slash loading on the stem-only treatment plots compared to the full-tree plots led to significantly lower species diversity on loam sites; however, the reverse was observed on peat sites where the slash provided warmer, drier microsites facilitating the establishment of a broader array of species. Preexisting ericaceous shrub and sphagnum components continued to dominate on the peat sites. Compositional shifts were most evident for the full-tree + bladed treatment on all soil types, with increases in herbaceous cover including ruderal species. The results suggest that the intensification of harvesting on plant diversity varies with soil type, and these differential results should be considered in the refinement of forest biomass-harvesting guidelines to ensure ecological sustainability and biodiversity conservation over a broad suite of soil types.

Can a novel combination of organic chemical analysis and inverse modeling help reconstruct the past upper forest line in the Ecuadorian Andes?

NASA Astrophysics Data System (ADS)

Jansen, B.; van Loon, E. E.; Nierop, K. G. J.

2009-04-01

The higher parts of the Ecuadorian Andes consist of fragile ecosystems characterized by páramo grasslands and montane cloud forests. Natural climatic change and human interference (i.a. burning and clear-cutting) are believed to have dramatically lowered the UFL in the area to the point that its natural position in the absence of disturbance is now uncertain. This is impeding our understanding of the response of the UFL to global climate change and hindering a correct strategy to reforest areas in the frame of Kyoto Protocol driven activities to fix carbon dioxide. An important cause of the uncertainty is that the traditional method of pollen analysis from peat or sediment deposits alone does not suffice to reconstruct shifts in the UFL. Reasons are the spatial uncertainty caused by wind-blown dispersal of pollen and the limited availability of peat or sediment deposits at all altitudes of interest. The RUFLE* program tackles this problem by combining traditional pollen and vegetation analyses with a novel biomarker approach. In the latter, plant species typical for specific vegetation zones are examined for the presence of biomarkers, defined as plant-specific (combinations of) organic chemical components. Our results show that the leaves and roots of the higher plants responsible for the dominant biomass input in our study area in the Eastern Cordillera in the Northern Ecuadorian Andes contain unique combinations of n-alkanes and n-alcohols in the carbon number range of C20-C36(1). Furthermore, we found these compounds to be well preserved in peat deposits and soils in chronological order for extended time periods (>6000 14C years B.P.)(2,3). As such they offer great potential to serve as biomarkers for past vegetation dynamics, including UFL shifts. However, since it are unique combinations of otherwise ubiquitous n-alkanes, n-alcohols of various carbon chain-lengths that constitute our biomarkers, unraveling the mixed signal of various plants accumulated in soils and peat sediment over time poses a major challenge. To tackle this problem, we developed the VERHIB model that describes the accumulation of biomarkers in soils and peat sediments(4). By inversion the most likely vegetation composition leading to the mixed biomarker signal in the soil or peat sediment in question can be derived. Here we describe the results of the first application of the model in a peat core and several soil monoliths at various altitudes from our study area. Our results show that biomarker analysis using the VERHIB model can indeed serve as a new proxy to reconstruct historic vegetation compositions including the UFL in the Ecuadorian Andes, yielding information that is highly complementary to that which can be obtained through traditional pollen analysis. This is a significant breakthrough from a paleo-ecological point of view as it means an additional proxy is available to be used in combination with traditional pollen- and vegetation analysis. In addition, it is a very promising result from an applied point of view as the information gained will aid the Ecuadorian government in its strategic decisions concerning reforestation of possibly degraded natural areas. 1)Jansen, B. Nierop, K.G.J., Hageman, J.A., Cleef, A.M. & Verstraten, J.M. 2006. The straight chain lipid biomarker composition of plant species responsible for the dominant biomass production along two altitudinal transects in the Ecuadorian Andes. Organic Geochemistry 37: 1514-1536. 2)Jansen, B. & Nierop, K.G.J. 2008. Methyl ketones in high altitude Ecuadorian Andosols confirm excellent conservation of plant-specific n-alkane patterns. Organic Geochemistry (in press). 3)Tonneijck, F.H. & Jongmans, A.G. 2008. The influence of bioturbation on the vertical distribution of soil organic matter in volcanic ash soils: a case study in Northern Ecuador. European Journal of Soil Science 59: 1063-1075. 4)Jansen, B., Van Loon, E.E., Hooghiemstra, H. & Verstraten, J.M. 2008. Analysis of plant biomarkers greatly improves reconstruction of palaeo-environments. Geology (submitted). *RUFLE stands for Reconstruction of the Upper Forest Line in Ecuador

The Use of Hotspot Spatial Clustering and Multitemporal Satellite Imagery to Facilitate Peat Land Degradation in West Kalimantan, Indonesia (Case Study in Mensiku Miniwatershed of Kapuas River)

NASA Astrophysics Data System (ADS)

Yanuarsyah, I.; Suwarno, Y.; Hudjimartsu, S.

2016-11-01

Peat land in Indonesia is currently a matter of interest to economic activity. In addition to having the uniqueness of the ecosystem which is reserve a huge of biodiversity and carbon storage, peat land is grow an alternative expansion of agriculture and plantation. Mensiku miniwatershed is a subset of Kapuas Watershed with the domination of the peat soil type. It located in the upstream from the Kapuas River and supporting for the continuation of the river ecosystem. The research objective is to facilitate peat land degradation by using hotspot spatial clustering and multitemporal satellite imagery. There have three main processes which are image processing, geoprocessing and statistical process using DBSCAN to determine hotspot clustering. The trend of LUC changes for 14 years (2002 to 2016) shows that the downward occurred in secondary peat forest (0.9% per year) and swampy shrub (0.6% per year). The upward occurred in mixed farms (0.6% per year) and plantations (0.8% per year). degradation rate of peat land over 14 years about 4.6 km2 per year. Hotspot predominantly occurrence in secondary peat forest with 200-250 centimeter depth and Saprists type. DBSCAN clustering obtain 2 clusters in 2002, obtain 4 clusters in 2009 and obtain 1 clusters in 2016. Regarding LUC platform, average density value over 14 years about 0.063 hotspot per km2. DBSCAN is common used to examine the cluster and perform the distribution and density with spatial analysis

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

NASA Astrophysics Data System (ADS)

Gosch, Lennart; Janssen, Manon; Lennartz, Bernd

2017-04-01

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

Biogeochemical plant-soil microbe feedback in response to climate warming in peatlands

NASA Astrophysics Data System (ADS)

Bragazza, Luca; Parisod, Julien; Buttler, Alexandre; Bardgett, Richard D.

2013-03-01

Peatlands act as global sinks of atmospheric carbon (C) through the accumulation of organic matter, primarily made up of decay-resistant litter of peat mosses. However, climate warming has been shown to promote vascular plant growth in peatlands, especially ericaceous shrubs. A change in vegetation cover is in turn expected to modify above-ground/below-ground interactions, but the biogeochemical mechanisms involved remain unknown. Here, by selecting peatlands at different altitudes to simulate a natural gradient of soil temperature, we show that the expansion of ericaceous shrubs with warming is associated with an increase of polyphenol content in both plant litter and pore water. In turn, this retards the release of nitrogen (N) from decomposing litter, increases the amount of dissolved organic N and reduces N immobilization by soil microbes. A decrease of soil water content with increasing temperature promotes the growth of fungi, which feeds back positively on ericaceous shrubs by facilitating the symbiotic acquisition of dissolved organic N. We also observed a higher release of labile C from vascular plant roots at higher soil temperatures, which promotes the microbial investment in C-degrading enzymes. Our data suggest that climate-induced changes in plant cover can reduce the productivity of peat mosses and potentially prime the decomposition of organic matter by affecting the stoichiometry of soil enzymatic activity.

Association of 16 priority polycyclic aromatic hydrocarbons with humic acid and humin fractions in a peat soil and implications for their long-term retention.

PubMed

Chen, Weixiao; Wang, Hui; Gao, Qian; Chen, Yin; Li, Senlin; Yang, Yu; Werner, David; Tao, Shu; Wang, Xilong

2017-11-01

To elucidate the environmental fate of polycyclic aromatic hydrocarbons (PAHs) once released into soil, sixteen humic acids (HAs) and one humin (HM) fractions were sequentially extracted from a peat soil, and sixteen priority PAHs in these humic substances (HSs) were analyzed. It was found that the total concentration of 16 PAHs (∑16PAHs) increased evidently from HA1 to HA16, and then dramatically reached the highest value in HM. The trend of ∑16PAHs in HAs relates to surface carbon and C-H/C-C contents, the bulk aliphatic carbon content and aliphaticity, as well as the condensation enhancement of carbon domains, which were derived from elemental composition, XPS, 13 C NMR, as well as thermal analyses. HM was identified to be the dominant sink of 16 PAHs retention in soil, due to its aliphatic carbon-rich chemical composition and the highly condensed physical makeup of its carbon domains. This study highlights the joint roles of the physical and chemical properties of HSs in retention of PAHs in soil and the associated mechanisms; the results are of significance for PAH-polluted soil risk assessment and remediation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Long-Term Uptake of Phenol-Water Vapor Follows Similar Sigmoid Kinetics on Prehydrated Organic Matter- and Clay-Rich Soil Sorbents.

PubMed

Borisover, Mikhail; Bukhanovsky, Nadezhda; Lado, Marcos

2017-09-19

Typical experimental time frames allowed for equilibrating water-organic vapors with soil sorbents might lead to overlooking slow chemical reactions finally controlling a thermodynamically stable state. In this work, long-term gravimetric examination of kinetics covering about 4000 h was performed for phenol-water vapor interacting with four materials pre-equilibrated at three levels of air relative humidity (RHs 52, 73, and 92%). The four contrasting sorbents included an organic matter (OM)-rich peat soil, an OM-poor clay soil, a hydrophilic Aldrich humic acid salt, and water-insoluble leonardite. Monitoring phenol-water vapor interactions with the prehydrated sorbents, as compared with the sorbent samples in phenol-free atmosphere at the same RH, showed, for the first time, a sigmoid kinetics of phenol-induced mass uptake typical for second-order autocatalytic reactions. The apparent rate constants were similar for all the sorbents, RHs and phenol activities studied. A significant part of sorbed phenol resisted extraction, which was attributed to its abiotic oxidative coupling. Phenol uptake by peat and clay soils was also associated with a significant enhancement of water retention. The delayed development of the sigmoidal kinetics in phenol-water uptake demonstrates that long-run abiotic interactions of water-organic vapor with soil may be overlooked, based on short-term examination.

Warming of subarctic tundra increases emissions of all three important greenhouse gases - carbon dioxide, methane, and nitrous oxide.

PubMed

Voigt, Carolina; Lamprecht, Richard E; Marushchak, Maija E; Lind, Saara E; Novakovskiy, Alexander; Aurela, Mika; Martikainen, Pertti J; Biasi, Christina

2017-08-01

Rapidly rising temperatures in the Arctic might cause a greater release of greenhouse gases (GHGs) to the atmosphere. To study the effect of warming on GHG dynamics, we deployed open-top chambers in a subarctic tundra site in Northeast European Russia. We determined carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) fluxes as well as the concentration of those gases, inorganic nitrogen (N) and dissolved organic carbon (DOC) along the soil profile. Studied tundra surfaces ranged from mineral to organic soils and from vegetated to unvegetated areas. As a result of air warming, the seasonal GHG budget of the vegetated tundra surfaces shifted from a GHG sink of -300 to -198 g CO 2 -eq m -2 to a source of 105 to 144 g CO 2 -eq m -2 . At bare peat surfaces, we observed increased release of all three GHGs. While the positive warming response was dominated by CO 2 , we provide here the first in situ evidence of increasing N 2 O emissions from tundra soils with warming. Warming promoted N 2 O release not only from bare peat, previously identified as a strong N 2 O source, but also from the abundant, vegetated peat surfaces that do not emit N 2 O under present climate. At these surfaces, elevated temperatures had an adverse effect on plant growth, resulting in lower plant N uptake and, consequently, better N availability for soil microbes. Although the warming was limited to the soil surface and did not alter thaw depth, it increased concentrations of DOC, CO 2, and CH 4 in the soil down to the permafrost table. This can be attributed to downward DOC leaching, fueling microbial activity at depth. Taken together, our results emphasize the tight linkages between plant and soil processes, and different soil layers, which need to be taken into account when predicting the climate change feedback of the Arctic. © 2016 John Wiley & Sons Ltd.

The sensitivity of peat soil and peatland vegetation to drought: release of dissolved organic carbon (DOC) on rewetting

NASA Astrophysics Data System (ADS)

Ritson, Jonathan; Graham, Nigel; Templeton, Michael; Freeman, Christopher; Clark, Joanna

2015-04-01

Organic rich peat soils are a major store of carbon worldwide. Their existence is predicated on high year-round water tables which create an anoxic environment, thus limiting decay, and also to the recalcitrance of plant litter (dead plant material) commonly found in peatland areas. Climate change threatens the stability of peat soils by altering the biogeochemical cycles which control plant decay, lowering water tables so that oxic degradation can occur and by changing habitat niches such that less recalcitrant species can thrive in peatlands. One of the major fluxes of carbon from peatlands is through dissolved organic carbon (DOC) in surface waters. As peatland areas in the UK are often used as source waters for drinking water supply this presents a problem to water utilities as DOC must be effectively removed to limit colour, odour and the formation of potentially carcinogenic by-products on disinfection. Changes in catchment vegetation may occur due to climate change, nutrient deposition and changing bioclimatic envelopes. How different peatland vegetation contribute to DOC flux and how this may change in the future is therefore of interest. A six week laboratory simulation was performed on typical peatland litter (Sphagnum spp., Calluna vulgaris, Molinea caerulea, Juncus effusus) and a peat soil collected from Exmoor National Park, UK. The simulation monitored DOC flux from the decaying litter/soil and considered the impact of different drought severities using the 50th, 25th, 10th and 5th percentiles of the mean July/August monthly rainfall for Exmoor. On rewetting following the drought, all sources produced significantly different amounts of DOC (Tukey HSD p<0.05) in the order Molinia>Juncus>Calluna>Sphagnum>peat. The source also had a significant (ANOVA p<0.001) effect on coagulation removal efficiency, a typical method of removing DOC during drinking water treatment, with Juncus DOC proving the easiest to remove whilst Sphagnum DOC was the most difficult. Sphagnum DOC had the lowest ratio of humic-like to protein-like fluorescence, which is indicative of DOC which is poorly removed by coagulation. An interactive effect was noted between DOC source and the drought treatment which was explored further using a one-way ANOVA with a Holm-Šidák correction. This suggested peat will produce significantly more DOC when affected by drought (p=0.010), possibly explained by increased oxygenation engaging the 'enzymatic latch' mechanism. A similar analysis was performed on the interaction between drought and DOC source for the specific UV absorbance at 254nm (SUVA) value (a measure of aromaticity). This suggested that Molinea caerulea produces DOC of significantly (p=0.001) higher aromaticity following periods of drought. Comparisons between drought and DOC source factors suggest the source in more important than climatic conditions of decay which is consistent with our previously published findings. These results have implications for marginal peatlands which may be at risk from increased water table drawdown in the future as climate changes and where Molinea caerulea, typically a fen species, is encroaching on bog communities.

Development of a multidisciplinary method for mapping spatial extent and C-content of tropical ombrotrophic peatlands

NASA Astrophysics Data System (ADS)

Illés, Gábor; Kristijono, Agus; Pfeifer, Norbert; Pásztor, László; Shandhyavitri, Ari; Szatmári, Gábor; Sutikno, Sigit; Molnár, Gábor; László, Péter; Árvai, Mátyás; Mészáros, János; Koós, Sándor; Bakacsi, Zsófia; Takács, Katalin; Király, Géza; Székely, Balázs

2017-04-01

One of the world's most worrying environmental problems is the peat land CO2 emission problem of Indonesia: peat lands developed during the Quaternary are now under strong human influence; the artificial lowering of the natural water table leads to rapid drying and compaction of the peat layer, which then becomes vulnerable to subsurface fire. The emitted CO2 of this process is assessed to be 0.5 billion tonnes from Indonesia that is slightly higher than total emission of e.g. United Kingdom in 2014 (0.42 billion tonnes). To cope with the problem it is inevitable to assess the extents of peat lands and volumetric estimation of the potentially affected layers. Methods suitable for mapping of the peat lands (current situation and as far as possible retrospectively), thickness determination and partly thickness estimation of the peat layer are integrated in an advanced geostatistical approach building upon geomorphic, ecological, remote sensing, and geophysical methods to provide information on peat matrix attributes such as peat thickness of organo-mineral horizons between peat and underlying substrate, the presence of buried wood, buttressed trees or tip-up pools and soil type. In order to cope with the problem, our research group is developing a multidisciplinary methodology making use of our experience in soil science, GIS, remote sensing for forestry and ecology, geomorphometry, geophysics, LiDAR remote sensing, parameter estimation and geostatistical methods. The methodology is based largely on GIS data integration, but also applies technologies of 'big data' processing. Our integrative attitude ensures the holistic consideration of the problem, analyzing its origins, temporal development and varying spatial extent, its subprocesses in a multi-scale, inter- and transdisciplinary approach. At the same time practical problems, feasibility, costs, and human resource need consideration in order to design a viable solution. In the development of the solution, elements of gathered experience is integrated acquired in previous similar projects in Hungary, in the Pannonian Basin and in Indonesia, in southern Kalimantan and Indragiri Hilir, Sumatra. The pointwise and profilewise data acquisition of peat forms is converted to mapping methods augmented with a sophisticated sampling strategy. Besides the similarities - freshwater, ombrotrophic peatlands - we also have to focus on remarkable dissimilarities - e.g., herbaceous vs. woody peat material. In the case of the Pannonian Basin the peat occurrences have been developed as the filling up of the floodplains. In the Indonesian case, however, only the basin flanks are partly comparable to that generation mechanism, whereas see level changes play an important role in the development of the vast Indonesian peat occurrences. Geomorphometric approach helps in designing the sample strategy, remote sensing tools are responsible to deliver high-resolution topographic data as input. The varying thickness is assessed with geophysical measurements and shallow boreholes deployed at sampling points and profiles dictated by the sophisticated sampling strategy. During the measurement and sampling the experience gathered is fed back to the sampling strategy giving a dynamic plan for the continuation of the sampling. The advanced evaluation and visualization techniques applied result in a digital map system that also contains estimates on its quality and accuracy in the spatial context. This new approach brings us closer to the understanding of Indonesian peatland development that may also be used elsewhere in similar environmental contexts.

Compositional and functional stability of aerobic methane consuming communities in drained and rewetted peat meadows.

PubMed

Krause, Sascha; Niklaus, Pascal A; Badwan Morcillo, Sara; Meima Franke, Marion; Lüke, Claudia; Reim, Andreas; Bodelier, Paul L E

2015-11-01

The restoration of peatlands is an important strategy to counteract subsidence and loss of biodiversity. However, responses of important microbial soil processes are poorly understood. We assessed functioning, diversity and spatial organization of methanotrophic communities in drained and rewetted peat meadows with different water table management and agricultural practice. Results show that the methanotrophic diversity was similar between drained and rewetted sites with a remarkable dominance of the genus Methylocystis. Enzyme kinetics depicted no major differences, indicating flexibility in the methane (CH4) concentrations that can be used by the methanotrophic community. Short-term flooding led to temporary elevated CH4 emission but to neither major changes in abundances of methane-oxidizing bacteria (MOB) nor major changes in CH4 consumption kinetics in drained agriculturally used peat meadows. Radiolabeling and autoradiographic imaging of intact soil cores revealed a markedly different spatial arrangement of the CH4 consuming zone in cores exposed to near-atmospheric and elevated CH4. The observed spatial patterns of CH4 consumption in drained peat meadows with and without short-term flooding highlighted the spatial complexity and responsiveness of the CH4 consuming zone upon environmental change. The methanotrophic microbial community is not generally altered and harbors MOB that can cover a large range of CH4 concentrations offered due to water-table fluctuations, effectively mitigating CH4 emissions. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

3D modelling of mechanical peat properties in the Holocene coastal-deltaic sequence of the Netherlands

NASA Astrophysics Data System (ADS)

Koster, Kay; Stouthamer, Esther; Cohen, Kim; Stafleu, Jan; Busschers, Freek; Middelkoop, Hans

2016-04-01

Peat is abundantly present within the Holocene coastal-deltaic sequence of the Netherlands, where it is alternating with clastic fluvial, estuarine and lagoonal deposits. The areas that are rich in peat are vulnerable to land subsidence, resulting from consolidation and oxidation, due to loading by overlying deposits, infrastructure and buildings, as well as excessive artificial drainage. The physical properties of the peat are very heterogeneous, with variable clastic admixture up to 80% of its mass and rapid decrease in porosity with increasing effective stress. Mapping the spatial distribution of the peat properties is essential for identifying areas most susceptible to future land subsidence, as mineral content determines volume loss by oxidation, and porosity influences the rate of consolidation. Here we present the outline of a study focusing on mapping mechanical peat properties in relation to density and amount of admixed clastic constituents of Holocene peat layers (in 3D). In this study we use a staged approach: 1) Identifying soil mechanical properties in two large datasets that are managed by Utrecht University and the Geological Survey. 2) Determining relations between these properties and palaeogeographical development of the area by evaluating these properties against known geological concepts such as distance to clastic source (river, estuary etc.). 3) Implementing the obtained relations in GeoTOP, which is a 3D geological subsurface model of the Netherlands developed by the Geological Survey. The model will be used, among others, to assess the susceptibility of different areas to peat related land subsidence and load bearing capacity of the subsurface. So far, our analysis has focused stage 1, by establishing empirical relations between mechanical peat properties in ~70 paired (piezometer) cone penetration tests and continuously cored boreholes with LOI measurements. Results show strong correlations between net cone resistance (qn), excess pore water (u1-u0), and total vertical stress (σvo), suggesting that the overburden strongly controls the vertical differential susceptibility of peat layers to consolidation.

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

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

Investigation of dielectric constant variations for Malaysians soil species towards its natural background dose

NASA Astrophysics Data System (ADS)

Jafery, Khawarizmi Mohd; Embong, Zaidi; Khee, Yee See; Haimi Dahlan, Samsul; Tajudin, Saiful Azhar Ahmad; Ahmad, Salawati; Kudnie Sahari, Siti; Maxwell, Omeje

2018-01-01

The correlation of natural background gamma radiation and real part of the complex relative permittivity (dielectric constant) for various species Malaysian soils was investigated in this research. The sampling sites were chosen randomly according to soils groups that consist of sedentary, alluvial and miscellaneous soil which covered the area of Batu Pahat, Kluang and Johor Bahru, Johor state of Malaysia. There are 11 types of Malaysian soil species that have been studied; namely Peat, Linau-Sedu, Selangor-Kangkong, Kranji, Telemong-Akob-Local Alluvium, Holyrood-Lunas, Batu Anam-Melaka-Tavy, Harimau Tampoi, Kulai-Yong Peng, Rengam-Jerangau, and Steepland soils. In-situ exposure rates of each soil species were measured by using portable gamma survey meter and ex-situ analysis of real part of relative permittivity was performed by using DAK (Dielectric Assessment Kit assist by network analyser). Results revealed that the highest and the lowest background dose rate were 94 ± 26.28 μR hr-1 and 7 ± 0.67 μR hr-1 contributed by Rengam Jerangau and Peat soil species respectively. Meanwhile, dielectric constant measurement, it was performed in the range of frequency between 100 MHz to 3 GHz. The measurements of each soils species dielectric constant are in the range of 1 to 3. At the lower frequencies in the range of 100 MHz to 600 MHz, it was observed that the dielectric constant for each soil species fluctuated and inconsistent. But it remained consistent in plateau form of signal at higher frequency at range above 600 MHz. From the comparison of dielectric properties of each soil at above 600 MHz of frequency, it was found that Rengam-Jerangau soil species give the highest reading and followed by Selangor-Kangkong species. The average dielectric measurement for both Selangor-Kangkong and Rengam-Jerangau soil species are 2.34 and 2.35 respectively. Meanwhile, peat soil species exhibits the lowest dielectric measurement of 1.83. It can be clearly seen that the pattern of dielectric measurement for every soil at the frequency above 600 MHz demonstrated a specific distribution which can be classified into two main regions which are higher and lower between the ranges of 1.83 to 2.35. Pearson correlation analysis between the frequency of 100 MHz and 2.6 GHz with respect to exposure rate for every soil species was r = 0.38 and r = 0.51, respectively. This indicates that there was no strong correlation between both parameter, natural background dose and soils dielectric for each soils sample. This factor could be contributed by major and minor elements contained in each soils sample species, especially Ferum, Fe and Silica, Si.

Developing and evaluating rapid field methods to estimate peat carbon

Treesearch

Rodney A. Chimner; Cassandra A. Ott; Charles H. Perry; Randall K. Kolka

2014-01-01

Many international protocols (e.g., REDD+) are developing inventories of ecosystem carbon stocks and fluxes at country and regional scales, which can include peatlands. As the only nationally implemented field inventory and remeasurement of forest soils in the US, the USDA Forest Service Forest Inventory and Analysis Program (FIA) samples the top 20 cm of organic soils...

Controls on boreal peat combustion and resulting emissions of carbon and mercury

NASA Astrophysics Data System (ADS)

Kohlenberg, Andrew J.; Turetsky, Merritt R.; Thompson, Dan K.; Branfireun, Brian A.; Mitchell, Carl P. J.

2018-03-01

Warming in the boreal forest region has already led to changes in the fire regime. This may result in increasing fire frequency or severity in peatlands, which could cause these ecosystems to shift from a net sink of carbon (C) to a net source of C to the atmosphere. Similar to C cycling, peatlands serve as a net sink for mercury (Hg), which binds strongly to organic matter and accumulates in peat over time. This stored Hg is also susceptible to re-release to the atmosphere during peat fires. Here we investigate the physical properties that influence depth of burn in experimental peat columns and the resulting emissions of CO, CO2, CH4, and gaseous and particulate Hg. As expected, bulk density and soil moisture content were important controls on depth of burn, CO2 emissions, and CO emissions. However, our results show that CH4 and Hg emissions are insensitive to combustion temperature or fuel moisture content. Emissions during the burning of peat, across a wide range of moisture conditions, were associated with low particulate Hg and high gaseous Hg release. Due to strong correlations between total Hg and CO emissions and because high Hg emissions occurred despite incomplete combustion of total C, our results suggest that Hg release during peat burning is governed by the thermodynamics of Hg reduction more so than by the release of Hg associated with peat combustion. Our measured emissions ratios, particularly for CH4:CO2, are higher than values typically used in the upscaling of boreal forest or peatland fire emissions. These emission ratios have important implications not only for our understanding of smouldering chemistry, but also for potential influences of peat fires on the Earth’s climate system.

Hybrid biosorbents for removal of pollutants and remediation

NASA Astrophysics Data System (ADS)

Burlakovs, Juris; Klavins, Maris; Robalds, Artis; Ansone, Linda

2014-05-01

For remediation of soils and purification of polluted waters, wastewaters, biosorbents might be considered as prospective groups of materials. Amongst them peat have a special role due to low cost, biodegradability, high number of functional groups, well developed surface area and combination of hydrophilic/hydrophobic structural elements. Peat as sorbent have good application potential for removal of trace metals, and we have demonstrated peat sorption capacities, sorption kinetics, thermodynamics in respect to metals with different valencies - Tl(I), Cu(II), Cr(III). However, peat sorption capacity in respect to nonmetallic (anionic species) elements is low. Also peat mechanical properties do not support application in large scale column processes thereby, to expand peat application sphere, the approach of biomass based hybrid sorbents has been elaborated. The concept "hybrid sorbent" in understanding of biosorbent means natural, biomass based modified material, covered with another sorbent material, thus combining properties of both such as sorbent functionalities, surface properties etc. As the "covering layer" both inorganic substances, mineral phases (iron oxohydroxides, oxyappatite) and organic polymers (using graft polymerization) were used. The obtained sorbents were characterised by their spectral properties, surface area and elemental composition. The obtained hybrid sorbents were tested for sorption of compounds in anionic speciation forms, for example of arsenic, antimony, tellurium and phosphorous compounds in comparison with weakly basic anionites. The highest sorption capacity was observed when peat sorbents modified with iron compounds were used. Sorption of different arsenic speciation forms onto iron-modified peat sorbents was investigated as a function of pH and temperature. It was established that sorption capacity increases with a rise in temperature as the calculation of sorption process thermodynamic parameters indicates the spontaneity of sorption process and its endothermic nature. The recycling options of obtained compounds after their saturation with metal or non-metallic species are suggested.

Two dimensional hydrological simulation in elastic swelling/shrinking peat soils

NASA Astrophysics Data System (ADS)

Camporese, M.; Ferraris, S.; Paniconi, C.; Putti, M.; Salandin, P.; Teatini, P.

2005-12-01

Peatlands respond to natural hydrologic cycles of precipitation and evapotranspiration with reversible deformations due to variations of water content in both the unsaturated and saturated zone. This phenomenon results in short-term vertical displacements of the soil surface that superimpose to the irreversible long-term subsidence naturally occurring in drained cropped peatlands because of bio-oxidation of the organic matter. The yearly sinking rates due to the irreversible process are usually comparable with the short-term deformation (swelling/shrinkage) and the latter must be evaluated to achieve a thorough understanding of the whole phenomenon. A mathematical model describing swelling/shrinkage dynamics in peat soils under unsaturated conditions has been derived from simple physical considerations, and validated by comparison with laboratory shrinkage data. The two-parameter model relates together the void and moisture ratios of the soil. This approach is implemented in a subsurface flow model describing variably saturated porous media flow (Richards' equation), by means of an appropriate modification of the general storage term. The contribution of the saturated zone to total deformation is considered by using information from the elastic storage coefficient. Simulations have been carried out for a drained cropped peatland south of the Venice Lagoon (Italy), for which a large data set of hydrological and deformation measurements has been collected since the end of 2001. The considered domain is representative of a field section bounded by ditches, subject to rainfall and evapotranspiration. The comparison between simulated and measured quantities demonstrates the capability of the model to accurately reproduce both the hydrological and deformation dynamics of peat, with values of the relevant parameters that are in good agreement with the literature.

Arsenic Transport and Transformation Associated with MSMA Application on a Golf Course Green

PubMed Central

Feng, Min; Schrlau, Jill E.; Snyder, Raymond; Snyder, George H.; Chen, Ming; Cisar, John L.; Cai, Yong

2008-01-01

The impact of extensively used arsenic-containing herbicides on groundwater beneath golf courses has become a topic of interest. Although currently used organoarsenicals are less toxic, their application into the environment may produce the more toxic inorganic arsenicals. The objective of this work was to understand the behavior of arsenic species in percolate water from monosodium methanearsonate (MSMA) applied golf course greens, as well as to determine the influences of root-zone media for United State Golf Association (USGA) putting green construction on arsenic retention and species conversion. The field test was established at the Fort Lauderdale Research and Education Center (FLREC), University of Florida. Percolate water was collected after MSMA application for speciation and total arsenic analyses. The results showed that the substrate composition significantly influenced arsenic mobility and arsenic species transformation in the percolate water. In comparison to uncoated sands (S) and uncoated sands and peat (S + P), naturally coated sands and peat (NS + P) showed a higher capacity of preventing arsenic from leaching into percolate water, implying that the coatings of sands with clay reduce arsenic leaching. Arsenic species transformation occurred in soil, resulting in co-occurrence of four arsenic species, arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in percolate water. The results indicated that substrate composition can significantly affect both arsenic retention in soil and arsenic speciation in percolate water. The clay coatings on the soil particles and the addition of peat in the soil changed the arsenic bioavailability, which in turn controlled the microorganism-mediated arsenic transformation. To better explain and understand arsenic transformation and transport after applying MSMA in golf green, a conceptual model was proposed. PMID:15853401

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

NASA Astrophysics Data System (ADS)

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

2014-12-01

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

AmeriFlux US-Snd Sherman Island

DOE Data Explorer

Baldocchi, Dennis [University of California, Berkeley

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-Snd Sherman Island. Site Description - The Sherman Island site is a 38-ha peatland pasture, west of the Delta, that is owned by the state and managed by the California Department of Water Resources. The site is degraded and heavily grazed with ~100 cattle in the area that circumscribes the main field and fetch. The island has been drained and farmed since the late 1800s. The soils of the Delta overlay deep peat that was sequestered over the Holocene period as sea-level rose and flooding of archaic wetlands prevented decomposition of roots and stems. Hence, the upper 10 m of peatland has been lost to decomposition, compaction, and subsidence. Today a mineral soil overlays a peat layer, which coincides with the general depth of the water table.

Investigating the relationship between peat biogeochemistry and above-ground plant phenology with remote sensing along a gradient of permafrost thaw.

NASA Astrophysics Data System (ADS)

Garnello, A.; Dye, D. G.; Bogle, R.; Hough, M.; Raab, N.; Dominguez, S.; Rich, V. I.; Crill, P. M.; Saleska, S. R.

2016-12-01

Global climate models predict a 50% - 85% decrease in permafrost area in northern regions by 2100 due to increased temperature and precipitation variability, potentially releasing large stores of carbon as greenhouse gases (GHG) due to microbial activity. Linking belowground biogeochemical processes with observable above ground plant dynamics would greatly increase the ability to track and model GHG emissions from permafrost thaw, but current research has yet to satisfactorily develop this link. We hypothesized that seasonal patterns in peatland biogeochemistry manifests itself as observable plant phenology due to the tight coupling resulting from plant-microbial interactions. We tested this by using an automated, tower-based camera to acquire daily composite (red, green, blue) and near infrared (NIR) images of a thawing permafrost peatland site near Abisko, Sweden. The images encompassed a range of exposures which were merged into high-dynamic-range images, a novel application to remote sensing of plant phenology. The 2016 growing season camera images are accompanied by mid-to-late season CH4 and CO2 fluxes measured from soil collars, and by early-mid-late season peat core samples of the composition of microbial communities and key metabolic genes, and of the organic matter and trace gas composition of peat porewater. Additionally, nearby automated gas flux chambers measured sub-hourly fluxes of CO2 and CH4 from the peat, which will also be incorporated into analysis of relationships between seasonal camera-derived vegetation indices and gas fluxes from habitats with different vegetation types. While remote sensing is a proven method in observing plant phenology, this technology has yet to be combined with soil biogeochemical and microbial community data in regions of permafrost thaw. Establishing a high resolution phenology monitoring system linked to soil biogeochemical processes in subarctic peatlands will advance the understanding of how observable patterns in plant phenology can be used to monitor permafrost thaw and ecosystem carbon cycling.

The sustainable management of ameliorated peatlands on changed land use conditions; scenarios of constrains and possibilities

NASA Astrophysics Data System (ADS)

Shanskiy, , Merrit; Vollmer, Elis; Penu, Priit

2015-04-01

The utilization of organic soils for forestry or agriculture requires the land amelioration that could result on the peat losses from 15 to 20 t ha-1 in a year on following five years. After five years, the peat losses will be 5 - 15 t ha-1 in a year. The agricultural land resource on different types of organic soils (including ameliorated bogs) in Estonia is 360 000 ha that comprises 41% of total agricultural land area. The landscape iself is a valuable resource that considered to be a set of characteristics that satisfy needs of people using the landscape: economical or non-economical value; ecological, social, recreational, aesthetical, educational, scientific or even protective value. More diverse landscapes have higher biodiversity and yield more services to public, they are also seen as more sustainable and resilient to short-term changes. In order to maintain landscape diversity, sustainable maintenance is important. The purpose of current study was to estimate the land use potential on three different ameliorated peat areas and to develop the methodology for the futher sustainable utilization in order to secure the best ecological functioning of soil while taking into account maintaining and increasing landscape value. Therefore, site specific soil sampling (n=77) was carried out on predetermined eight study sites. Soil samples were analyzed for main agrochemical parameters (n=17; pHKCl, P, K, C%, N%, S%, ash, main anions and cations). This enables determing site-specific best suitable crops and land use scenarios. For the land resource description (soils type, topology) the digital soil map (1: 10,000) and field sudy based database were used for describing the model areas. For more specific identification of the field layers the Agricultural Registers and Information Board (ARIB) and databases of the Common Agricultural Policy (CAP) payments were used for subsidy schemes chekout. Estonian Nature Information System map tool was used to specify the restrictions on study sites by nature conversation on the maps data about nature protected objects and buffer zones or forming restricted areas around those objects. The results will indicate the utilization possibility and most sustainable scenarios for different land use cases. Moreover, the possible changes in soil functioning accordingly to site specific soil conditions will be discussed and presented.

The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

USGS Publications Warehouse

Kirwanm, M.L.; Langley, J.A.; Guntenspergen, Gleen R.; Megonigal, J.P.

2013-01-01

The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

NASA Astrophysics Data System (ADS)

Kirwan, M. L.; Langley, J. A.; Guntenspergen, G. R.; Megonigal, J. P.

2013-03-01

The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

NASA Astrophysics Data System (ADS)

Kirwan, M. L.; Langley, J. A.; Guntenspergen, G. R.; Megonigal, J. P.

2012-10-01

The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

Size and XAD fractionations of trihalomethane precursors from soils.

PubMed

Chow, Alex T; Guo, Fengmao; Gao, Suduan; Breuer, Richard S

2006-03-01

Soil organic matter is an important source of allochthonous dissolved organic matter inputs to the Sacramento-San Joaquin Delta waterways, which is a drinking water source for 22 million people in California, USA. Knowledge of trihalomethane (THM) formation potential of soil-derived organic carbon is important for developing effective strategies for organic carbon removal in drinking water treatment. In this study, soil organic carbon was extracted with electrolytes (deionized H2O and Na- or Ca-based electrolytes) of electrical conductivity bracketing those found in Delta leaching and runoff conditions. The extracts were physically and chemically separated into different fractions: colloidal organic carbon (0.45-0.1 microm), fine colloidal organic carbon (0.1-0.025 microm), and dissolved organic carbon (DOC) (<0.025 microm); hydrophobic acid (HPOA), transphilic acid, and hydrophilic acid. Two representative Delta soils, Rindge Muck (a peat soil) and Scribner Clay Loam (a mineral soil) were examined. Results showed that less than 2% of soil organic carbon was electrolyte-extractable and heterogeneous organic fractions with distinct THM reactivity existed. Regardless of soil and electrolytes, DOC and HPOA fractions were dominant in terms of total concentration and THMFP. The amounts of extractable organic carbon and THMFP were dependent on the cation and to a lesser extent on electrical conductivity of electrolytes. Along with our previous study on temperature and moisture effects on DOC production, we propose a conceptual model to describe the impacts of agricultural practices on DOC production in the Delta. DOC is mainly produced in the surface peat soils during the summer and is immobilized by accumulated salt in the soils. DOC is leached from soils to drainage ditches and finally to the Delta channels during winter salt leaching practices.

Long-term effects of peatland cultivation on soil physical and hydraulic properties: Case study in Canada

Treesearch

Dennis W. Hallema; Jonathan A. Lafond; Yann Périard; Silvio J. Gumiere; Ge Sun; Jean Caron

2015-01-01

Organic soils are an excellent substrate for commercial lettuce (Lactuca sativa L.) farming; however, drainage accelerates oxidation of the surface layer and reduces the water holding capacity, which is often lethal for crops that are sensitive to water stress. In this case study, we analyzed 942 peat samples from a large cultivated peatland complex...

Measurement of Physical and Hydraulic Properties of Organic Soil Using Computed Tomographic Imagery

NASA Astrophysics Data System (ADS)

Blais, K. E.; Quinton, W. L.; Heck, R. J.; Price, J. S.; Schmidt, M. G.

2005-12-01

The Lower Liard River valley is located within the continental northern boreal region and the zone of discontinuous permafrost. Lying in the centre of the Mackenzie basin, this valley is an extensive flat headwater region with a high density of open water and peatlands. Several standard methods of measuring the physical properties of organic soils exist, although many of them have several drawbacks that limit their use. Organic soils, in particular, have unique properties that require special attention to ensure that the measured hydrological characteristics are represented as they exist in nature. The goal of this research was to devise an improved method of analyzing and measuring the physical and hydraulic properties of organic soil using MicroCT imagery. Specifically, this research seeks to determine if two and three-dimensional images of peat can be used to accurately characterize air-filled porosity, active porosity, pore size distribution, pore saturated area and capillarity of porous Sphagnum cells. Results indicate that measurements derived from these images are consistent with current literature. They also suggest that this non-destructive method is a valuable tool for measuring peat physical and hydraulic properties and that there is potential for additional research using CT technology.

Speciation of sulfur in humic and fulvic acids using X-ray absorption near-edge structure (XANES) spectroscopy

NASA Astrophysics Data System (ADS)

Morra, Matthew J.; Fendorf, Scott E.; Brown, Paul D.

1997-02-01

Sulfur species in soils and sediments have previously been determined indirectly using destructive techniques. A direct and more accurate method for S speciation would improve our understanding of S biogeochemistry. X-ray absorption near edge structure (XANES) spectroscopy was performed on purified humic and fulvic acids from terrestrial and aquatic environments. This methodology allows direct determination of S species using the relationship that exists with the energy required for core electron transitions and in some cases, correlation with additional spectral features. Soil, peat, and aquatic humic acids were dominated by sulfonates with an oxidation state of +5, but also contained ester-bonded sulfates with an oxidation state of +6. Leonardite humic acid contained ester-bonded sulfate and an unidentified S compound with an oxidation state of +4.0. In contrast, high-valent S in soil, peat, and aquatic fulvic acids was exclusively in the form of sulfonic acids. Reduced S species were also present in both humic and fulvic acids. XANES is a valuable method for the speciation of S in humic materials and of potential use in S speciation of unfractionated soils.

Peat hybrid sorbents for treatment of wastewaters and remediation of polluted environment

NASA Astrophysics Data System (ADS)

Klavins, Maris; Burlakovs, Juris; Robalds, Artis; Ansone-Bertina, Linda

2015-04-01

For remediation of soils and purification of polluted waters, wastewaters, sorbents might be considered as an prospective group of materials and amongst them peat have a special role due to low cost, biodegradability, high number of functional groups, well developed surface area and combination of hydrophilic/hydrophobic structural elements. Peat as sorbent have good application potential for removal of trace metals, and we have demonstrated peat sorption capacities, sorption kinetics, thermodynamics in respect to metals with different valencies - Tl(I), Cu(II), Cr(III). However peat sorption capacity in respect to nonmetallic (anionic species) elements is low. Also peat mechanical properties do not support application in large scale column processes. To expand peat application possibilities the approach of biomass based hybrid sorbents has been elaborated. The concept "hybrid sorbent" in our understanding means natural, biomass based sorbent modified, covered with another sorbent material, thus combining two types of sorbent properties, sorbent functionalities, surface properties etc. As the "covering layer" both inorganic substances, mineral phases (iron oxohydroxides, oxyapatite) both organic polymers (using graft polymerization) were used. The obtained sorbents were characterised by their spectral properties, surface area, elemental composition. The obtained hybrid sorbents were tested for sorption of compounds in anionic speciation forms, for example of arsenic, antimony, tellurium and phosphorous compounds in comparison with weakly basic anionites. The highest sorption capacity was observed when peat sorbents modified with iron compounds were used. Sorption of different arsenic speciation forms onto iron-modified peat sorbents was investigated as a function of pH and temperature. It was established that sorption capacity increases with a rise in temperature, and the calculation of sorption process thermodynamic parameters indicates the spontaneity of sorption process and its endothermic nature. The recycling options of obtained compounds after their saturation with metal or non-metallic species are suggested. Acknowledgement: Support from a project 2014/0009/1DP/1.1.1.2.0/13/APIA/VIAA/044

The response of soil carbon storage and microbially mediated carbon turnover to simulated climatic disturbance in a northern peatland forest. Revisiting the concept of soil organic matter recalcitrance

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

Kostka, Joel

The goal of this project was to investigate changes in the structure of dissolved and solid phase organic matter, the production of CO 2 and CH 4, and the composition of decomposer microbial communities in response to the climatic forcing of environmental processes that determine the balance between carbon gas production versus storage and sequestration in peatlands. Cutting-edge analytical chemistry and next generation sequencing of microbial genes were been applied to habitats at the Marcell Experimental Forest (MEF), where the US DOE’s Oak Ridge National Laboratory and the USDA Forest Service are constructing a large-scale ecosystem study entitled, “Spruce andmore » Peatland Responses Under Climatic and Environmental Change”(SPRUCE). Our study represented a comprehensive characterization of the sources, transformation, and decomposition of organic matter in the S1 bog at MEF. Multiple lines of evidence point to distinct, vertical zones of organic matter transformation: 1) the acrotelm consisting of living mosses, root material, and newly formed litter (0-30 cm), 2) the mesotelm, a mid-depth transition zone (30-75 cm) characterized by labile organic C compounds and intense decomposition, and 3) the underlying catotelm (below 75cm) characterized by refractory organic compounds as well as relatively low decomposition rates. These zones are in part defined by physical changes in hydraulic conductivity and water table depth. O-alkyl-C, which represents the carbohydrate fraction in the peat, was shown to be an excellent proxy for soil decomposition rates. The carbon cycle in deep peat was shown to be fueled by modern carbon sources further indicating that hydrology and surface vegetation play a role in belowground carbon cycling. We provide the first metagenomic study of an ombrotrophic peat bog, with novel insights into microbial specialization and functions in this unique terrestrial ecosystem. Vertical structuring of microbial communities closely paralleled the chemical evolution of peat, with large shifts in microbial populations occurring in the biogeochemical hotspot, the mesotelm, where the highest rates of decomposition were detected. Stable isotope geochemistry and potential rates of methane production paralleled vertical changes in methanogen community composition to indicate a predominance of acetoclastic methanogenesis mediated by the Methanosarcinales in the mesotelm, while hydrogen-utilizing methanogens dominated in the deeper catotelm. Evidence pointed to the availability of phosphorus as well as nitrogen limiting the microbially-mediated turnover of organic carbon at MEF. Prior to initiation of the experimental treatments, our study provided key baseline data for the SPRUCE site on the vertical stratification of peat decomposition, key enzymatic pathways, and microbial taxa containing these pathways. The sensitivity of soil carbon turnover to climate change is strongly linked to recalcitrant carbon stocks and the temperature sensitivity of decomposition is thought to increase with increasing molecular complexity of carbon substrates. This project delivered results on how climate change perturbations impact the microbially-mediated turnover of recalcitrant organic matter in peatland forest soils, both under controlled conditions in the laboratory and at the ecosystem-scale in the field. This project revisited the concept of “recalcitrance” in the regulation of soil carbon turnover using a combination of natural abundance radiocarbon and optical spectroscopic measurements on bulk DOM, and high resolution molecular characterization of DOM. The project elucidated how organic matter reactivity and decomposition will respond to climate change in a both a qualitative (organic matter lability) and quantitiative (increased rates) manner. An Aromaticity Index was developed to represent a more direct and accurate parameter for modeling of DOM reactivity in peatlands. The abundance and community composition of soil microorganisms that mediate C cycling were interrogated with depth in the peat, with season, and in manipulated climate enclosures at unprecedented resolution. Therefore this project delivered strategic new insights on the functioning of peatland ecosystems that collectively store approximately one-third of the world's soil carbon. Furthermore, results from the detailed characterization of DOM lability and microbial community structure/ function will be employed to further develop biogeochemical models to include microbial respiration pathways as well as to track carbon flow with a term that incorporates relative reactivity based on aromaticity index. As it stands now, detailed soil organic matter structure and microbial parameters are not included in Earth system models.« less

Atmospheric Deposition of Trace Elements in Ombrotrophic Peat as a Result of Anthropic Activities

NASA Astrophysics Data System (ADS)

Fabio Lourençato, Lucio; Cabral Teixeira, Daniel; Vieira Silva-Filho, Emmanoel

2014-05-01

Ombrotrophic peat can be defined as a soil rich in organic matter, formed from the partial decomposition of vegetable organic material in a humid and anoxic environment, where the accumulation of material is necessarily faster than the decomposition. From the physical-chemical point of view, it is a porous and highly polar material with high adsorption capacity and cation exchange. The high ability of trace elements to undergo complexation by humic substances happens due to the presence of large amounts of oxygenated functional groups in these substances. Since the beginning of industrialization human activities have scattered a large amount of trace elements in the environment. Soil contamination by atmospheric deposition can be expressed as a sum of site contamination by past/present human activities and atmospheric long-range transport of trace elements. Ombrotrophic peat records can provide valuable information about the entries of trace metals into the atmosphere and that are subsequently deposited on the soil. These trace elements are toxic, non-biodegradable and accumulate in the food chain, even in relatively low quantities. Thus studies on the increase of trace elements in the environment due to human activities are necessary, particularly in the southern hemisphere, where these data are scarce. The aims of this study is to evaluate the concentrations of mercury in ombrotrophic peat altomontanas coming from atmospheric deposition. The study is conducted in the Itatiaia National Park, Brazilian conservation unit, situated between the southeastern state of Rio de Janeiro, São Paulo and Minas Gerais. An ombrotrophic peat core is being sampled in altitude (1980m), to measure the trace elements concentrations of this material. As it is conservation area, the trace elements found in the samples is mainly from atmospheric deposition, since in Brazil don't exist significant lithology of trace elements. The samples are characterized by organic matter content which is determined by calcination and pH. For the determination of mercury, an aliquot of 10 mL of sample with 5 mL of the reducing agent 2 % SnCl2, purged with air by atomic absorption spectrophotometry by cold vapor, EAAVF is being used. The determination of other trace elements (Zn, Cd and Pb) is analyzed by flame atomic absorption spectroscopy (FAAS).

A Molecular Budget for a Peatland Based Upon 13C Solid-State Nuclear Magnetic Resonance

NASA Astrophysics Data System (ADS)

Moody, Catherine S.; Worrall, Fred; Clay, Gareth D.; Burt, Tim P.; Apperley, David C.; Rose, Rob

2018-02-01

Peatlands can accumulate organic matter into long-term carbon (C) storage within the soil profile. This study used solid-state 13C nuclear magnetic resonance (13C-NMR) to investigate the transit of organic C through a peatland ecosystem to understand the molecular budget that accompanies the long-term accumulation of C. Samples of biomass, litter, peat soil profile, particulate organic matter, and dissolved organic matter (DOM) were taken from the Moor House National Nature Reserve, a peat-covered catchment in northern England where both the dry matter and C budget for the ecosystem were known. The results showed that: The interpretation of the 13C-NMR spectra shows that polysaccharides are preferentially removed through the ecosystem, while lignin components are preferentially retained and come to dominate the organic matter accumulated at depth in the profile. The DOM is derived from the oxidation of both biomass and the degradation of lignin, while the particulate organic matter is derived from erosion of the peat profile. The DOM is differentiated by its proportion of oxidized functional groups and not by its aromatic content. The changes in functionality leading to DOM production suggest side chain oxidation resulting in C-C cleavage/depolymerisation of lignin, a common reaction within white rot fungi. The 13C-NMR budget shows that O-alkyl functional groups are disproportionately lost between primary production and accumulation in the deep peat, while C-alkyl functional groups are disproportionately preserved. The carbon lost as gases (CO2 and CH4) was estimated to be composed of 93% polysaccharide-derived carbon and 7% lignin-derived carbon.

Linking pulses of atmospheric deposition to DOC release in an upland peat-covered catchment

NASA Astrophysics Data System (ADS)

Worrall, F.; Burt, T. P.; Adamson, J. K.

2008-12-01

Changes in atmospheric deposition have been proposed as one possible explanation of the widespread increase in DOC concentration observed in many Northern Hemisphere catchments. This study uses detailed, long-term, monthly monitoring records of pH, conductivity SO4, and DOC in precipitation, soil water, and runoff chemistry from an upland peat-covered catchment in northern England. By deriving impulse transfer functions this study explores whether changes in deposition lead to significant changes in the occurrence of each component in the soil and runoff water; especially significant changes in DOC. The study shows that (1) impulses in the deposition of acidity have no significant effect upon pH or DOC in soil water or runoff. (2) DOC in soil water and runoff is responsive to impulses in SO4 and conductivity, but only when those impulses are changes in soil water chemistry and not when they are in atmospheric deposition. (3) The effects of changes in SO4 and/or conductivity can easily be overemphasized if memory effects are not accounted for, and their effect is limited to only 1 or 2 months after a severe drought. This study can support the view that changes in ionic strength can result in changes in DOC concentration in soil water or runoff, but the system studied is unresponsive to changes in atmospheric deposition. Impulses in soil water SO4 do not lead to increases in DOC concentrations, and so this mechanism does not provide an explanation for DOC increases.

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

NASA Astrophysics Data System (ADS)

Shotyk, William

2010-05-01

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

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.

The flux of organic matter through a peatland ecosystem: The role of cellulose, lignin, and their control of the ecosystem oxidation state

NASA Astrophysics Data System (ADS)

Worrall, Fred; Moody, Catherine S.; Clay, Gareth D.; Burt, Tim P.; Rose, Rob

2017-07-01

This study used thermogravimetric analysis (TGA) to study the transit of organic C through a peatland ecosystem. The biomass, litter, peat soil profile, particulate organic matter (POM), and dissolved organic matter (DOM) fluxes were sampled from the Moor House National Nature Reserve, a peat-covered catchment in northern England where both the dry matter and carbon budget for the catchment were known. The study showed that although TGA traces showed distinct differences between organic matter reservoirs and fluxes, the traces could not readily be associated with particular functionalities or elemental properties. The TGA trace shows that polysaccharides are preferentially removed by humification and degradation with residual peat being dominated by lignin compositions. The DOM is derived from the degradation of lignin while the POM is derived from erosion of the peat profile. The carbon lost as gases (CO2 and CH4) was estimated to be composed of 92 to 95% polysaccharide carbon. The composition of the organic matter lost from the peat ecosystem means that the oxidative ratio (OR) of the ecosystem experienced by the atmosphere was between 0.96 and 0.99: currently, the Intergovernmental Panel on Climate Change uses an OR value of 1.1 for all ecosystems.

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.

Layered storage of biogenic methane-enriched gas bubbles in peat: A lumped capacitance model controlled by soil structure

NASA Astrophysics Data System (ADS)

Chen, X.; Comas, X.; Binley, A. M.; Slater, L. D.

2017-12-01

Methane can accumulate in the gaseous phase in peats, and enter the atmosphere as gas bubbles with a mass flux higher than that via diffusion and plant-mediated pathways. A complete understanding of the mechanisms regulating bubble storage in peats remains incomplete. We developed a layered model to quantify the storage of gas bubbles over a peat column based on a general lumped capacitance model. This conceptual model was applied to explain the effects of peat structure on bubble storage at different depths observed in a laboratory experiment. A peat monolith was collected from the Everglades, a subtropical wetland located in Florida (USA), and kept submerged in a cuboid chamber over 102 days until gas bubble saturation was achieved. Time-lapse ground-penetrating radar (GPR) was used to estimate changes in gas content of each layer and the corresponding average dimensions of stored gas bubbles. The results highlight a hotspot layer of bubble accumulation at depths between 5 and 10 cm below the monolith surface. Bubbles in this shallow hotspot layer were larger relative to those in deeper layers, whilst the degree of decomposition of the upper layers was generally smaller than that of the lower layers based on von Post humification tests. X-ray Computer tomography (CT) was applied to resin-impregnated peat sections from different depths and the results showed that a higher porosity promotes bubbles storage. The stored gas bubbles were released by changing water levels and the air CH4 concentrations above the peat monolith were measured using a flow-through chamber system to confirm the high CH4 concentration in the stored bubbles. Our findings suggest that bubble capacitance is related to the difference in size between gas bubbles and peat pores. This work has implications for better understanding how changes in water table elevation associated with climate change and sea level rise (particularly for freshwater wetlands near coastal areas like the Everglades) may potentially alter bubble sizes, thus bubble storage in peats.

Effect of biobed composition, moisture, and temperature on the degradation of pesticides.

PubMed

del Pilar Castillo, Maria; Torstensson, Lennart

2007-07-11

Biobeds retain and degrade pesticides through the presence of a biobed mixture consisting of straw, peat, and soil. The effects of biobed composition, moisture content, and temperature on pesticide degradation were investigated in laboratory studies. Straw produced the main microbial activity in the biobed mixtures as strong positive correlations were observed between straw, respiration, and phenoloxidase content. Most pesticides investigated were dissipated by cometabolic processes, and their dissipation was correlated with respiration and/ or phenoloxidase content. More pesticides were more dissipated at biobed moisture levels of 60% water holding capacity (WHC) than at 30% and 90% WHC, while 20 degrees C gave higher dissipation rates than 2 and 10 degrees C. A straw:peat:soil ratio of 50:25:25% v/v is recommended in field biobeds since this produces high microbial activity and low pH, favorable for lignin-degrading fungi and phenoloxidase activity.

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.

Spectral Assessment of Soil Properties: Standoff Quantification of Soil Organic Matter Content in Surface Mineral Soils and Alaskan Peat

DTIC Science & Technology

2017-08-01

ER D C TR -1 7- 9 ERDC 6.1 Geospatial Research and Engineering (GRE) and ERDC 6.2 GRE ARTEMIS STO-R DRTSPORE Spectral Assessment of...The U.S. Army Engineer Research and Development Center (ERDC) solves the nation’s toughest engineering and environmental challenges. ERDC...published by ERDC, visit the ERDC online library at http://acwc.sdp.sirsi.net/client/default. ERDC 6.1 Geospatial Research and Engineering (GRE) and

Effects of permafrost melting on CO2 and CH4 exchange of a poorly drained black spruce lowland

USGS Publications Warehouse

Wickland, K.P.; Striegl, Robert G.; Neff, J.C.; Sachs, T.

2006-01-01

Permafrost melting is occurring in areas of the boreal forest region where large amounts of carbon (C) are stored in organic soils. We measured soil respiration, net CO2 flux, and net CH4 flux during May-September 2003 and March 2004 in a black spruce lowland in interior Alaska to better understand how permafrost thaw in poorly drained landscapes affects land-atmosphere CO2 and CH4 exchange. Sites included peat soils underlain by permafrost at ???0.4 m depth (permafrost plateau, PP), four thermokarst wetlands (TW) having no permafrost in the upper 2.2 m, and peat soils bordering the thermokarst wetlands having permafi7ost at ???0.5 in depth (thermokarst edges, TE). Soil respiration rates were not significantly different among the sites, and 5-cm soil temperature explained 50-91% of the seasonal variability in soil respiration within the sites. Groundcover vegetation photosynthesis (calculated as net CO2 minus soil respiration) was significantly different among the sites (TW > TE > PP), which can be partly attributed to the difference in photosynthetically active radiation reaching the ground at each site type. Methane emission rates were 15 to 28 times greater fi7om TW than from TE and PP. We modeled annual soil respiration and groundcover vegetation photosynthesis using soil temperature and radiation data, and CH4 flux by linear interpolation. We estimated all sites as net C gas sources to the atmosphere (not including tree CO2 uptake at PP and TE), although the ranges in estimates when accounting for errors were large enough that TE and TW may have been net C sinks. Copyright 2006 by the American Geophysical Union.

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

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

Spontaneous plant colonization of brownfield soil and sludges and effects on substrate properties and pollutants mobility

NASA Astrophysics Data System (ADS)

Rocco, Claudia; Agrelli, Diana; Gonzalez, Maria Isabel; Mingo, Antonio; Motti, Riccardo; Stinca, Adriano; Coppola, Ida; Adamo, Paola

2017-04-01

This work was done on brownfield soil and sludges from a dismantled steel plant, moderately polluted by heavy metals (mainly Pb and Zn), 1) to analyzed the effects of substrate properties and environmental conditions on spontaneous vegetation; 2) to assess changes in the chemical properties of soils and sludges, with particular reference to the mobility and bioavailability of pollutants, induced by spontaneous plants revegetation. From 2006 to 2011, spontaneous plant colonization was monitored in the presence or absence of acidic peat both inside the degraded brownfield site and after transferal into a nearby Oak Park environment. During the five experimental years the vegetation growth was monitored using phytosociological method and data analyzed statistically. Both substrates, before and after plant growth, were analyzed for main chemical properties. Metals mobility and bioavailability was assessed using single (H2O; DTPA) and sequential extractions (EU-BCR). At the end of the experiment, plant ability to uptake metal was evaluated on selected species. Overall, 57 plant species grew healthily on the substrates. The combination of soil and sludges with peat resulted in an effective revegetation with a sensible increasing of plants biomass. Most of the species were found in the park (91%), showing plant colonization was mainly affected by the immediate environment rather than by substrate properties. Furthermore, after the five years, the substrate properties (pH, O.C.) were slightly affected by plant growth and, although metal pollutants in both substrates are characterized by low water solubility and DTPA availability, after plants growth an increase (even if not significant) of rhizospheric Cu, Fe, Mn and Zn solubility in H2O was detected. Metals speciation indicated a low risk of Pb and Zn mobility being either largely trapped in the mineralogical structure of oxides and silicates and occluded in easily reducible manganese or iron oxides. Restricted metal uptake and tissue accumulation by selected plants were measured, with only Daucus carota showing a higher ability to translocate metals to shoots (shoot/root metal concentration quotient >1 with peat). Water always underestimated plant uptake, while DTPA and sequential extractions better predicted Pb and Zn uptake. Phytostabilization with native plant species can be an efficient, environmentally appropriate and low cost technology for rehabilitation of industrial sites. The addition of organic matter may help the spontaneous re-vegetation and could facilitate the recovery of degraded environment. However, the changing induced by peat and plants might induced a solubilization of metal pollutants. A continuous monitoring of the potential changes of pollutants mobility-bioavailability by plants is crucial to prevent risks to the environment and human health. Key words: Heavy metals, phytoremediation, Peat addition, bioavailability, sequential extractions

Metabolic and trophic interactions modulate methane production by Arctic peat microbiota in response to warming

PubMed Central

Tveit, Alexander Tøsdal; Urich, Tim; Frenzel, Peter; Svenning, Mette Marianne

2015-01-01

Arctic permafrost soils store large amounts of soil organic carbon (SOC) that could be released into the atmosphere as methane (CH4) in a future warmer climate. How warming affects the complex microbial network decomposing SOC is not understood. We studied CH4 production of Arctic peat soil microbiota in anoxic microcosms over a temperature gradient from 1 to 30 °C, combining metatranscriptomic, metagenomic, and targeted metabolic profiling. The CH4 production rate at 4 °C was 25% of that at 25 °C and increased rapidly with temperature, driven by fast adaptations of microbial community structure, metabolic network of SOC decomposition, and trophic interactions. Below 7 °C, syntrophic propionate oxidation was the rate-limiting step for CH4 production; above this threshold temperature, polysaccharide hydrolysis became rate limiting. This change was associated with a shift within the functional guild for syntrophic propionate oxidation, with Firmicutes being replaced by Bacteroidetes. Correspondingly, there was a shift from the formate- and H2-using Methanobacteriales to Methanomicrobiales and from the acetotrophic Methanosarcinaceae to Methanosaetaceae. Methanogenesis from methylamines, probably stemming from degradation of bacterial cells, became more important with increasing temperature and corresponded with an increased relative abundance of predatory protists of the phylum Cercozoa. We concluded that Arctic peat microbiota responds rapidly to increased temperatures by modulating metabolic and trophic interactions so that CH4 is always highly produced: The microbial community adapts through taxonomic shifts, and cascade effects of substrate availability cause replacement of functional guilds and functional changes within taxa. PMID:25918393

Degradation and adsorption of pesticides in compost-based biomixtures as potential substrates for biobeds in southern Europe.

PubMed

Karanasios, Evangelos; Tsiropoulos, Nikolaos G; Karpouzas, Dimitrios G; Ehaliotis, Constantinos

2010-08-25

Biobeds have been used in northern Europe for minimizing point source contamination of water resources by pesticides. However, little is known regarding their use in southern Europe where edaphoclimatic conditions and agriculture practices significantly differ. A first step toward their adaptation in southern Europe is the use of low-cost and easily available substrates as biomixture components. This study investigated the possibility of replacing peat with agricultural composts in the biomixture. Five composts from local substrates including olive leaves, cotton crop residues, cotton seeds, spent mushroom substrate, and commercial sea wrack were mixed with topsoil and straw (1:1:2). Degradation of a mixture of pesticides (dimethoate, indoxacarb, buprofezin, terbuthylazine, metribuzin, metalaxyl-M, iprodione, azoxystrobin) at two dose rates was tested in the compost biomixtures (BX), in corresponding peat biomixtures (OBX), and in soil. Adsorption-desorption of selected pesticides were also studied. Pesticide residues were determined by gas chromatography with nitrogen-phosphorus detector, except indoxacarb, which was determined with a microelectron capture detector. Overall, BX degraded the studied pesticides at rates markedly higher than those observed in soil and OBX, in which the slowest degradation rates were evident. Overall, the olive leaf compost biomixture showed the highest degradation capacity. Adsorption studies showed that OBX and BX had higher adsorption affinity compared to soil. Desorption experiments revealed that pesticide adsorption in biomixtures was not entirely reversible. The results suggest that substitution of peat with local composts will lead to optimization of the biobed system for use in Mediterranean countries.

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

NASA Astrophysics Data System (ADS)

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

2010-12-01

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

Nitrosation and nitration of fulvic acid, peat and coal with nitric acid

USGS Publications Warehouse

Thorn, Kevin A.; Cox, Larry G.

2016-01-01

Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture. The nitration chemistry however is incompletely understood. Moreover, there is a need to understand the reaction of nitric acid with natural organic matter (NOM) in general, in the context of a variety of environmental and biogeochemical processes. Suwannee River NOM, Suwannee River fulvic acid, and Pahokee Peat fulvic acid were treated with 15N-labeled nitric acid at concentrations ranging from 15% to 22% and analyzed by liquid and solid state 15N NMR spectroscopy. Bulk Pahokee peat and Illinois #6 coal were also treated with nitric acid, at 29% and 40% respectively, and analyzed by solid state 15N NMR spectroscopy. In addition to nitro groups from nitration of aromatic carbon, the 15N NMR spectra of all five samples exhibited peaks attributable to nitrosation reactions. These include nitrosophenol peaks in the peat fulvic acid and Suwannee River samples, from nitrosation of phenolic rings, and N-nitroso groups in the peat samples, from nitrosation of secondary amides or amines, the latter consistent with the peat samples having the highest naturally abundant nitrogen contents. Peaks attributable to Beckmann and secondary reactions of the initially formed oximes were present in all spectra, including primary amide, secondary amide, lactam, and nitrile nitrogens. The degree of secondary reaction product formation resulting from nitrosation reactions appeared to correlate inversely with the 13C aromaticities of the samples. The nitrosation reactions are most plausibly effected by nitrous acid formed from the reduction of nitric acid by oxidizable substrates in the NOM and coal samples.

Nitrosation and Nitration of Fulvic Acid, Peat and Coal with Nitric Acid

PubMed Central

Thorn, Kevin A.; Cox, Larry G.

2016-01-01

Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture. The nitration chemistry however is incompletely understood. Moreover, there is a need to understand the reaction of nitric acid with natural organic matter (NOM) in general, in the context of a variety of environmental and biogeochemical processes. Suwannee River NOM, Suwannee River fulvic acid, and Pahokee Peat fulvic acid were treated with 15N-labeled nitric acid at concentrations ranging from 15% to 22% and analyzed by liquid and solid state 15N NMR spectroscopy. Bulk Pahokee peat and Illinois #6 coal were also treated with nitric acid, at 29% and 40% respectively, and analyzed by solid state 15N NMR spectroscopy. In addition to nitro groups from nitration of aromatic carbon, the 15N NMR spectra of all five samples exhibited peaks attributable to nitrosation reactions. These include nitrosophenol peaks in the peat fulvic acid and Suwannee River samples, from nitrosation of phenolic rings, and N-nitroso groups in the peat samples, from nitrosation of secondary amides or amines, the latter consistent with the peat samples having the highest naturally abundant nitrogen contents. Peaks attributable to Beckmann and secondary reactions of the initially formed oximes were present in all spectra, including primary amide, secondary amide, lactam, and nitrile nitrogens. The degree of secondary reaction product formation resulting from nitrosation reactions appeared to correlate inversely with the 13C aromaticities of the samples. The nitrosation reactions are most plausibly effected by nitrous acid formed from the reduction of nitric acid by oxidizable substrates in the NOM and coal samples. PMID:27175784

Growing Media Affect Size of Container-Grown Red Pine

Treesearch

Howard M. Phipps

1974-01-01

Red pine seedlings were grown in nine different soil media and in two types of containers in a greenhouse. Growth differed significantly among the media after 16 weeks, with the largest seedlings produced in a peat-vermiculite mix

HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

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

Raivonen, Maarit; Smolander, Sampo; Backman, Leif

Wetlands are one of the most significant natural sources of methane (CH 4) to the atmosphere. They emit CH 4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH 4, in addition to carbon dioxide (CO 2). Production of CH 4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH 4 emissions are thus needed for upscaling observations to estimate present CH 4 emissions and for producing scenarios of future atmospheric CH 4 concentrations. Aiming at a CH 4 model that can bemore » added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH 4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH 4, CO 2, and oxygen (O 2) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH 4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH 4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH 4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of the total CH 4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O 2 concentrations that affect the CH 4 production and oxidation rates; (4) with given input respiration, the peat column description does not significantly affect the simulated CH 4 emissions in this model version.« less

HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

NASA Astrophysics Data System (ADS)

Raivonen, Maarit; Smolander, Sampo; Backman, Leif; Susiluoto, Jouni; Aalto, Tuula; Markkanen, Tiina; Mäkelä, Jarmo; Rinne, Janne; Peltola, Olli; Aurela, Mika; Lohila, Annalea; Tomasic, Marin; Li, Xuefei; Larmola, Tuula; Juutinen, Sari; Tuittila, Eeva-Stiina; Heimann, Martin; Sevanto, Sanna; Kleinen, Thomas; Brovkin, Victor; Vesala, Timo

2017-12-01

Wetlands are one of the most significant natural sources of methane (CH4) to the atmosphere. They emit CH4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH4, in addition to carbon dioxide (CO2). Production of CH4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH4 emissions are thus needed for upscaling observations to estimate present CH4 emissions and for producing scenarios of future atmospheric CH4 concentrations. Aiming at a CH4 model that can be added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH4, CO2, and oxygen (O2) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of the total CH4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O2 concentrations that affect the CH4 production and oxidation rates; (4) with given input respiration, the peat column description does not significantly affect the simulated CH4 emissions in this model version.

HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

DOE PAGES

Raivonen, Maarit; Smolander, Sampo; Backman, Leif; ...

2017-12-22

Wetlands are one of the most significant natural sources of methane (CH 4) to the atmosphere. They emit CH 4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH 4, in addition to carbon dioxide (CO 2). Production of CH 4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH 4 emissions are thus needed for upscaling observations to estimate present CH 4 emissions and for producing scenarios of future atmospheric CH 4 concentrations. Aiming at a CH 4 model that can bemore » added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH 4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH 4, CO 2, and oxygen (O 2) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH 4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH 4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH 4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of the total CH 4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O 2 concentrations that affect the CH 4 production and oxidation rates; (4) with given input respiration, the peat column description does not significantly affect the simulated CH 4 emissions in this model version.« less

Changes in the geodiversity of Dutch peatlands inferred from 19th and 20th century landscape paintings

NASA Astrophysics Data System (ADS)

Jungerius, Pieter Dirk; van den Ancker, Hanneke; Wevers, Nina

2013-04-01

Geodiversity is the natural and cultural range of geological, geomorphological and soil features. We analysed the large database of 19th and early 20th century paintings of Simonis and Buunk (www.Simonis-Buunk.com) to track changes in the geodiversity of Dutch peatlands since pre-photographic times. Peat dominated in two of the eight main landscapes of the Netherlands: the Lowland peats in the Holocene west and the Highland peats in the sandy Pleistocene eastern parts. Painters were mainly attracted by the lowland peats. Since more than thousand years, peat plays a major role in Dutch military security, economy, ecology and cultural life. Natural variety and cultural use resulted in a geodiversity that is unique in Europe. There are more than 100 place names with 'veen' (= peat), and surnames with 'veen' are common. Proof of the exploitation of peat for salt and fuel exists from the Roman times onwards. In the 9th century, peatlands were drained and reclaimed for growing wheat. Already in the 11th century, it was necessary to build dikes to prevent flooding, to control waterlevels to avoid further oxidation, and to convert landuse to grassland. But subsidence continued, and in the 14th century windmills were needed to drain the lands and pump the water out. In the 16th century industrial peat exploitation fuelled the rise of industries and cities. All this draining and digging caused the peat surface to shrink. The few remaining living peats are conserved by nature organisations. Geodiversity and landscape paintings In the peat landscapes, popular painting motives were high water levels, the grasslands of the 'Green Heart', the winding streams and remaining lakes. The paintings of landscapes where peat had been removed, show watermanagement adaptations: wind mills, different water levels, canals made for the transport of fuel, bridges, tow paths and the 'plassen', i.e. the lakes left after peat exploitation. The droogmakerijen (reclaimed lakes), now 2 to 5 m below sealevel, were less inspiring. Examples of geodiversity changes illustrated by the landscape paintings • Peat extraction stopped • Land use changed e.g. the deforestation of the 'Bovenlanden' • Erosion by waves and boats caused the collapse of peat islands in the artificial lakes • Peat polders of the Green Heart were sacrificed for building projects • 90% of the original wind mills were replaced by electrical and motor pumps • Horse traction was replaced by motor vehicles, which made tow paths and high wooden bridges redundant. • Dam burst risk increased and skating scenes disappeared with climate change, References Jungerius, P.D., 2010. Sea level rise and the response of the Dutch people - Adaptive strategies based on geomorphologic principles give sustainable solutions. In: Martini I.P.& Chesworth, W.(eds.) Landscapes and Societies. Springer Verlag.

Chemical characteristics of dissolved organic matter (DOM) in relation to heavy metal concentrations in soil water from boreal peatlands after clear-cut harvesting

NASA Astrophysics Data System (ADS)

Kiikkilä, O.; Nieminen, T.; Starr, M.; Ukonmaanaho, L.

2012-04-01

Boreal peatlands form an important terrestrial carbon reserve and are a major source of dissolved organic matter (DOM) to surface waters, particularly when disturbed through forestry practices such as draining or timber harvesting. Heavy metals show a strong affinity to organic matter and so, along with DOM, heavy metals can be mobilized and transported from the soil to surface waters and sediments where they may become toxic to aquatic organisms and pass up the food chain. The complexation of heavy metals with DOM can be expected to be related and determined by the chemical characteristics of DOM and oxidation/reducing conditions in the peat. We extracted interstitial water from peat samples and determined the concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and Al, Cu, Zn and Fe in various fractions of DOM isolated by adsorption properties (XAD-8 fractionation) and molecular-weight (ultrafiltration). The peat samples were taken from 0-30 and 30-50 cm depth in drained peatland catchments two years after whole-tree or stem-only clear-cut harvesting (Scots pine or Norway spruce) had been carried out. The samples from the upper layer had been subject to alternating saturation/aeration conditions while the deeper layer had been continuously under the water table. The fractionation of DOC and DON according to both adsorption properties and molecular-weight fractions clearly differed between the upper and lower peat layers. While the hydrophobic acid fraction contained proportionally more DOC and DON than the hydrophilic acid fraction in the upper peat layer the results were vice versa in the lower peat layer. High-molecular-weight compounds (> 100 kDa) were proportionally more abundant in the upper and low-molecular-weight compounds (< 1 kDa) in the lower peat layer. These differences are assumed to reflect differences in the aerobic/ anaerobic conditions and degree of decomposition between the two layers. The concentrations of Zn, Al, Fe and DON correlated positively with DOC concentrations whereas the concentration Cu did not correlate with DOC concentrations. Heavy metal concentrations in different molecular-weight fractions indicated that Al, Cu, Zn and Fe were mostly associated with high-molecular-weight compounds and only a small fraction existed as free metal ions in solution. There were no clear differences in the chemical characteristics of DOC or DON or heavy metal concentrations between the two harvesting treatments.

Plant diversity affects GHG fluxes in an ecological engineering experiment in a disturbed Sphagnum peatland (La Guette, France)

NASA Astrophysics Data System (ADS)

Gogo, Sébastien; Laggoun-Défarge, Fatima; Leroy, Fabien; Guimbaud, Christophe; Bernard-Jannin, Léonard

2017-04-01

Many Sphagnum peatlands are experiencing vegetation change caused mainly by hydrological disturbances. In the context of these direct and indirect modifications, greenhouse gases (GHG) fluxes are affected by peat oxygenation, changes in litter composition (and thus decomposition) and rhizospheric processes (such as root exudates). This could lead a C sink system to switch to a source. To restore peatland functioning, ecological engineering works can be undertaken. Our study site, La Guette peatland (central France) is invaded by Molinia caerulea because a drain at the output decreased the water table depth. It was shown that it functioned as a source of C. In 2014, hydrological works were undertaken: 8 dams were installed, ditches were dug perpendicular to the water flow and back-filled with a mixture of shales and bentonite. In addition, a biodiversity experiment with 2 identical experimental stations was implemented: "downstream", close to the hydraulic works (relatively wet), "upstream", (relatively dry), with types of 3 vegetation plot (2m x 2m, n=4): 1) "control": intact vegetation (Molinia caerulea, Erica tetralix), 2) "bare" peat: vegetation and 5cm of peat were removed, 3) "Sphagnum": bare peat+Sphagnum. Our study aims to assess the effect of the vegetation treatment on the GHG fluxes. CO2 (ecosystem respiration or ER, Gross Primary Production or GPP, and Net Ecosystem Exchange) and CH4 fluxes (manual accumulation chamber), air and soil temperature, water table level, soil moisture were measured. After 18 months, half of the surface of "bare" and "Sphagnum" plots were covered by vegetation (Eriophorum angustifolium, Rynchospora alba, Trichophorum cespitosum). With time, as succession unfolds in these 2 types of station, ER and GPP increased. The sensitivity of ER to temperature increased sharply in "bare" and "Sphagnum" plots with years and became higher than the sensitivity in "control" plots. GPP increased with the total vegetation percentage cover, especially in "bare" peat plots. NEE were still lower in the "bare" and "sphagnum" peat plots than in "control". However, the difference tends to decrease. In November 2015, the "sphagnum" peat plots were still functioning as a sink of C, whereas the other plots functioned as a source. As a conclusion, the "bare" and "sphagnum" treatments, after 3 years, were not able to store C as much as the control during the daytime measurements undertaken. C budget for each treatment still have to be calculated to determine the sink or source functioning of the different treatment.

Transport, anoxia and energy control on anaerobic respiration and methanogenesis in anoxic peat soils

NASA Astrophysics Data System (ADS)

Bonaiuti, Simona; Blodau, Christian; Knorr, Klaus-Holger

2017-04-01

In deep and permanently water saturated peat deposits, extremely low diffusive transport and concomitant build-up of metabolic end-products, i.e of dissolved inorganic carbon (DIC) and methane (CH4), have been found to slow-down anaerobic respiration and methanogenesis. Such accumulation of DIC and CH4 lowers the Gibbs free energy yield of terminal respiration and methanogenesis, which can inhibit the course of anaerobic metabolic processes. In particular, this affects terminal steps of the breakdown of organic carbon (C), such as methanogenesis, acetogenesis and fermentation processes, which occur near thermodynamic minimum energy thresholds. This effect is thus of critical importance for the long-term C sequestration, as the slow-down of decomposition ultimately regulates the long-term fate of C in deep peat deposits. The exact controls of this observed slow-down of organic matter mineralization are not yet fully understood. Moreover, altered patterns of water or gas transport due to predicted changes in climate may affect these controls in peat soils. Therefore, the aim of this study was to investigate how burial of peat leads to an inactivation of anaerobic decomposition and to investigate the effects of advective water transport and persistently anoxic conditions on anaerobic decomposition, temporal evolution of thermodynamic energy yields to methanogenesis and methanogenic pathways. To this end, we conducted a column experiment with homogenized, ombrotrophic peat over a period of 300 days at 20˚ C. We tested i) a control treatment under diffusive transport only, ii) an advective flow treatment with a flow of 10 mm d-1, and iv) an anoxic treatment to evaluate changes in decomposition in absence of oxygen in the unsaturated zone of the cores. A slow-down of anaerobic respiration and methanogenesis generally set in at larger depths after 150 days at CH4 concentrations of 0.6-0.9 mmol L-1 and DIC concentrations of 6-12 mmol L-1. This effect occurred at higher concentration levels and faster than previously observed. Advective water transport effectively extended the zone of methanogenesis down to 40 cm depth until inhibiting conditions were reached, although net turnover at greater depths was not affected. Strictly anoxic conditions in the unsaturated zone, where diffusive transport is high, had little effect on accelerating anaerobic decomposition. The slow-down of net production rates of CO2 and CH4 agreed well with the decline over time of Gibbs free energies available to methanogenesis, supporting a thermodynamic constraint on decomposition in deeper peat deposits. Keywords: Peatlands; Anaerobic decomposition; Methanogenesis; Production rates; Advection; Anoxia; Thermodynamic calculations.

[Trace element supply to ruminants in the German Democratic Republic. 2. Supply of copper].

PubMed

Anke, M; Groppel, B; Lüdke, H; Grün, M; Kleemann, J

1975-06-01

The supply of copper to ruminants as influenced by and depending on the geological origin of soils was investigated in different parts of the GDR by using the hair test. Red clovers (meadow clover and field clover) were used as indicator plants. The following results were obtained: Data on the Cu content of clovers grown on soils of the same geological origin were found to correlate with r = 0,81. After eliminating the effects of Cu antagonists resulting from industrial pollution it was possible to establish numerical relations (B = 0.39 and B = 0.89) between the relative values (specific for the particular location) for the Cu content of the indicator plants and the percentage of cows suffering from Cu deficiencies (6.0 and 5.0 ppm Cu in hair). The lowest percentages of Cu supply to the ruminants (established on the basis of the Cu content of red clovers) were found on diluvial sandy soils, glacial loams and peat and bog soils whereas the highest percentages of Cu were found on weathered soils (of phyllite, gneiss, shell limestone, red marl soils and porphyry). Secondary Cu deficiencies in ruminants may arise, independent of the geological origin of the soil material, in places exposed to the main direction of the winds from major industrial areas (emission of SO2, Cd and Mo). Due to primary and/or secondary deficiencies the supply of Cu to ruminants in various locations (syenite, granite, red sandstone, gneiss, loess; peat soils, diluvial sandy soils) may be insufficient. A detailed description is given of areas where Cu deficiency is likely to occur and recommendations are given on how to use mineral mixtures containing a high proportion of Cu (1.00 g Cu per kg).

Biologically Active Organic Matter in Soils of European Russia

NASA Astrophysics Data System (ADS)

Semenov, V. M.; Kogut, B. M.; Zinyakova, N. B.; Masyutenko, N. P.; Malyukova, L. S.; Lebedeva, T. N.; Tulina, A. S.

2018-04-01

Experimental and literature data on the contents and stocks of active organic matter in 200 soil samples from the forest-tundra, southern-taiga, deciduous-forest, forest-steppe, dry-steppe, semidesert, and subtropical zones have been generalized. Natural lands, agrocenoses, treatments of long-term field experiments (bare fallow, unfertilized and fertilized crop rotations, perennial plantations), and different layers of soil profile are presented. Sphagnum peat and humus-peat soil in the tundra and forest-tundra zones are characterized by a very high content of active organic matter (300-600 mg C/100 g). Among the zonal soils, the content of active organic matter increases from the medium (75-150 mg C/100 g) to the high (150-300 mg C/100 g) level when going from soddy-podzolic soil to gray forest and dark-gray forest soils and then to leached chernozem. In the series from typical chernozem to ordinary and southern chernozem and chestnut and brown semidesert soils, a decrease in the content of active organic matter to the low (35-75 mg C/100 g) and very low (<35 mg C/100 g) levels is observed. Acid brown forest soil in the subtropical zone is characterized by a medium supply with active organic matter. Most arable soils are mainly characterized by low or very low contents of active organic matter. In the upper layers of soils, active organic matter makes up 1.2-11.1% of total Corg. The profile distribution of active organic matter in the studied soils coincides with that of Corg: their contents appreciably decrease with depth, except for brown semidesert soil. The stocks of active organic matter vary from 0.4 to 5.4 t/ha in the layer of 0-20 cm and from 1.0 to 12.4/ha in the layer of 0-50 cm of different soil types.

Interactive effects of wildfire and permafrost thaw on peatland carbon cycling

NASA Astrophysics Data System (ADS)

Olefeldt, David; Heffernan, William; Gibson, Carolyn; Burd, Katheryn; Estop-Aragones, Cristian

2017-04-01

Boreal peatland complexes in western Canada are fine-scale mosaics of permafrost affected peat plateaus interspersed with Sphagnum dominated thermokarst bogs where permafrost is absent. Wildfire further affects landscape patterning of peatland complexes, where virtually all peat plateaus are in a stage of secondary succession following wildfire. With climate change we expect both permafrost thaw and wildfire activity to increase in these landscapes, and to have important impacts on carbon cycling. In a number of studies, we have used soil chamber techniques to assess the influence of both permafrost thaw and wildfire on soil respiration, net ecosystem exchange and methane emissions. We used chronosequences to assess the influence of time since both permafrost thaw (3 - 15 years) and wildfire (20 - 150 years). Radiocarbon signatures of soil respiration in both burned and thawed locations was used to determine the contribution of aged soil carbon to soil respiration. We furthermore characterized individual and interactive effects of fire and thaw on microbial and photochemical lability of dissolved organic matter. At many field sites it was clear that recent wildfire had accelerated permafrost thaw, and we combined field observations of soil thermal regimes with remote sensing approaches to assess the role of wildfire for accelerating permafrost thaw over the last 50 years at a regional scale. Overall, our results highlight the need to consider both individual and interacting effects of thaw and fire for projections of the future carbon cycling at the regional level.

Psychrotolerant bacteria for remediation of oil-contaminated soils in the Arctic

NASA Astrophysics Data System (ADS)

Svarovskaya, L. I.; Altunina, L. K.

2017-12-01

Samples of oil-contaminated peat soil are collected in the region of the Barents Sea in Arctic Kolguyev Island. A model experiment on biodegradation of polluting hydrocarbons by natural microflora exhibiting psychrophilic properties is carried out at +10°C. The geochemical activity of pure hydrocarbon-oxidizing Acinetobacter, Pseudomonas, Bacillus and Rhodococcus cultures isolated from the soil is studied at a lower temperature. The concentration of soil contamination is determined within the range 18-57 g/kg. The biodegradation of oil by natural microflora is 60% under the conditions of a model experiment.

Could managed burning of peatlands lead to carbon storage?

NASA Astrophysics Data System (ADS)

Clay, G.; Worrall, F.

2007-12-01

Peatlands are the UK's largest single terrestrial carbon store with carbon stored in UK peatlands than in forests of Britain and France combined. Unlike most northern peatlands in the peat soils of the UK are heavily managed for recreation and agriculture and due to their proximity to major centres of population are under more anthropogenic pressure than most peatlands. A typical management strategy on UK upland peats is the use of managed fire to restrict vegetation. Fires are used upon a 10-25 year rotation and are described as "cool" as they remove the crown of the vegetation without scorching the litter layer or the underlying soil. In this case the fire destroys primary productivity and limits litter production but produces char. Char is a low volume, highly refractory, high carbon content product while litter is a high volume, decomposable, lower carbon content product. Therefore, the question is if there are fire conditions underwhich the production of char causes more carbon to be stored in the peat than would have been stored if no fire management had been employed. This study uses detailed vegetation studies from a long term monitoring site in order to assess litter and biomass production; in laboratory experimental burns were undertaken in order to assess the amount and controls upon char production and the carbon content of that char. Results of field and laboratory observations are used to model carbon accumulation under s aseries of fire management scenarios and the modelling shows that cools burns at long rotations could lead to higher carbon storage than if no fire had occurred, further than in several cases more carbon accumulation occurred even if less depth of peat was generated.

Could managed burning of peatlands lead to enhanced carbon storage?

NASA Astrophysics Data System (ADS)

Worrall, F.; Clay, G. D.

2009-04-01

Peatlands are the UK's largest single terrestrial carbon store with carbon stored in UK peatlands than in forests of Britain and France combined. Unlike most northern peatlands in the peat soils of the UK are heavily managed for recreation and agriculture and due to their proximity to major centres of population are under more anthropogenic pressure than most peatlands. A typical management strategy on UK upland peats is the use of managed fire to restrict vegetation. Fires are used upon a 10-25 year rotation and are described as "cool" as they are designed to remove the crown of the vegetation without scorching the litter layer or the underlying soil. In this case the fire destroys primary productivity and limits litter production but produces char. Char is a low volume, highly refractory, high carbon content product while litter is a high volume, decomposable, lower carbon content product. Therefore, the question is if there are fire conditions under which the production of char causes more carbon to be stored in the peat than would have been stored if no fire management had been employed. This study combines field studies of recent managed burns and wildfires along with detailed vegetation studies from a long term monitoring site in order to assess litter, biomass and black carbon production. In the laboratory experimental burns were undertaken in order to assess the amount and controls upon char production and the carbon content of that char. Results of field and laboratory observations are used to model carbon accumulation under a series of fire management scenarios and the modelling shows that cools burns at long rotations could lead to higher carbon storage than if no fire had occurred, further in several cases more carbon accumulation occurred even if less depth of peat was generated.

Testing hypotheses for the use of Icelandic volcanic ashes as low cost, natural fertilizers

NASA Astrophysics Data System (ADS)

Seward, W.; Edwards, B.

2012-04-01

Andisols are soils derived from tephra/volcanic bedrock and are generally considered to be fertile for plant growth (cf. University of Hawaii at Manoa, CTAHR). However, few studies have been published examining the immediate effects of the addition of volcanic ash to soils immediately after an eruption. Our research is motivated by unpublished accounts from Icelandic farmers that the growing season following the 2010 Eyjafjallajökull eruption ended with unusually high yields in areas that were covered by ash from the eruption early in the spring. To test the hypothesis that addition of volcanic ash to soil would have no immediate effect on plant growth, we conducted a ~6 week growth experiment in at controlled environment at the Dickinson College Farm. The experiment used relatively fast growing grain seeds as a test crop, controlled watering, known quantities of peat as an organic base, and the following general experimental design: peat was mixed in known but systematically differing proportions with 1) commercial quartz sand, 2) basaltic ash from the 2004 Grimsvötn eruption, and 3) trachyandesite ash from the 2010 Eyjafjallajökull eruption. For all experiments, the seeds growing in the simulated soil created with the two different composition volcanic ash had higher germination rates, higher growth rates, and produced plants that were healthier in appearance than the soil made from peat mixed with quartz sand. Some differences were also noted between the germination and grow rates between the basaltic and trachyandesitic ash experiments as well. Working hypotheses to explain these results include (1) shard shapes and vesicles from volcanic ash provide better water retention than quartz, allowing water to be stored longer and increasing average soil moisture, and (2) chemical nutrients from the ash facilitate germination and growth of plants. Documenting the potential benefits of fresh volcanic ash as a fertilizer is important as use of fresh ash fertlizer could lower the cost of raising crops in countries disrupted by explosive volcanic eruptions and turn a short-term negative associated with volcanic eruptions (ash fall) into a societal benefit (local source of inexpensive fertilizer). However, long term studies are also important to document how changes to ash during pedogenesis might affect long term soil structure and fertility.

Influence of Potassium on Sapric Peat under Different Environmental Conditions

NASA Astrophysics Data System (ADS)

Tajuddin, Syafik Akmal Mohd; Rahman, Junita Abdul; Rahim, Nor Haakmal Abd; Saphira Radin Mohamed, Radin Maya; Saeed Abduh Algheethi, Adel Ali, Dr

2018-04-01

Potassium is mainly present in soil in the natural form known as the K-bearing mineral. Potassium is also available in fertilizer as a supplement to plants and can be categorized as macronutrient. The application of potassium improves the texture and structure of the soil beside to improves plant growth. The main objective of this study was to determine the concentration of potassium in sapric peat under different conditions. Physical model was used as a mechanism for the analysis of the experimental data using a soil column as an equipment to produce water leaching. In this investigation, there were four outlets in the soil column which were prepared from the top of the column to the bottom with the purpose of identifying the concentration of potassium for each soil level. The water leaching of each outlet was tested using atomic absorption spectroscopy (AAS). The results obtained showed that the highest concentrations of potassium for flush condition at outlet 4 was 13.58 ppm. Similarly, sapric under rainwater condition recorded the highest value of 13.32 and 12.34 ppm respectively at outlet 4 for wet and dry condition. However, the difference in Sapric, rainwater and fertilizer category showed that the highest value for the wet condition was achieved at outlet 2 with 13.99 ppm while highest value of 14.82 ppm was obtained for the dry condition at the outlet 3. It was concluded that the outlets in the soil column gave a detailed analysis of the concentration of potassium in the soil which was influenced by the environmental conditions.

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

NASA Astrophysics Data System (ADS)

Shotyk, William

2013-04-01

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

Dissolved organic carbon export and its contribution to the carbon budget in a boreal peat landscape undergoing rapid permafrost thaw

NASA Astrophysics Data System (ADS)

Sonnentag, O.; Fouche, J.; Helbig, M.; Karoline, W.; Hould Gosselin, G.; Hanisch, J.; Quinton, W. L.; Moore, T. R.

2017-12-01

Northern permafrost soils store 1035 ± 150 Pg of organic carbon in the first 3 m. In boreal lowlands with warm and thin isolated, sporadic and discontinuous permafrost, increasing temperatures cause a thaw-induced expansion of permafrost-free wetlands at the expense of forested permafrost peat plateaus. Permafrost thaw associated with warmer soils may enhance microbial decomposition of near-surface and deeper organic matter but also increase dissolved organic carbon (DOC) export to aquatic systems. Recent studies suggest that, under a warmer climate, the current net CO2 sink strength of boreal peat landscapes may decline over the next few decades, eventually turning them into net CO2 sources. DOC export from these organic-rich landscapes undergoing rapid permafrost thaw may play a non-negligible role for the carbon budget in a warmer climate. In this study, we quantify the DOC export from a boreal peat landscape in the southern Northwest Territories (Canada). We use half-hourly discharge measurements and DOC concentrations sampled at the outlets of three small catchments ( 0.1 km2) to quantify runoff and DOC export from April to August 2014, 2015 and 2016. We estimate the DOC export contribution to the overall carbon budget using concurrent eddy covariance measurements of net CO2 and methane exchanges. The primary control of DOC export is discharge. In 2016, 70% of the DOC was exported during the two weeks of the spring freshet in early May. DOC export from the three catchments was 3g C m-2 from April to August, which accounted for 15% of the annual net ecosystem exchange. For the same period, the cumulative methane emissions were 6 g C-CH4 m-2. Our findings suggest that thawing boreal peat landscapes along the southern limit of permafrost currently act as net carbon sinks with 11 g C m-2 y-1. Investigating the optical properties of the dissolved organic matter across the different landforms (e.g., transition between forested permafrost peat plateau and permafrost-free wetland) will allow us to assess the different contributions to catchment DOC export and better forecast the changes in DOC lability with permafrost thaw and wetland expansion. Associated with a more rainfall-controlled runoff regime, changes in DOC export with warming may affect the carbon budget in the southern boundaries of the permafrost region.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Patterns and drivers of fungal community depth stratification in Sphagnum peat.

PubMed

Lamit, Louis J; Romanowicz, Karl J; Potvin, Lynette R; Rivers, Adam R; Singh, Kanwar; Lennon, Jay T; Tringe, Susannah G; Kane, Evan S; Lilleskov, Erik A

2017-07-01

Peatlands store an immense pool of soil carbon vulnerable to microbial oxidation due to drought and intentional draining. We used amplicon sequencing and quantitative PCR to (i) examine how fungi are influenced by depth in the peat profile, water table and plant functional group at the onset of a multiyear mesocosm experiment, and (ii) test if fungi are correlated with abiotic variables of peat and pore water. We hypothesized that each factor influenced fungi, but that depth would have the strongest effect early in the experiment. We found that (i) communities were strongly depth stratified; fungi were four times more abundant in the upper (10-20 cm) than the lower (30-40 cm) depth, and dominance shifted from ericoid mycorrhizal fungi to saprotrophs and endophytes with increasing depth; (ii) the influence of plant functional group was depth dependent, with Ericaceae structuring the community in the upper peat only; (iii) water table had minor influences; and (iv) communities strongly covaried with abiotic variables, including indices of peat and pore water carbon quality. Our results highlight the importance of vertical stratification to peatland fungi, and the depth dependency of plant functional group effects, which must be considered when elucidating the role of fungi in peatland carbon dynamics. Published by Oxford University Press on behalf of FEMS 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Classifying and mapping wetlands and peat resources using digital cartography

USGS Publications Warehouse

Cameron, Cornelia C.; Emery, David A.

1992-01-01

Digital cartography allows the portrayal of spatial associations among diverse data types and is ideally suited for land use and resource analysis. We have developed methodology that uses digital cartography for the classification of wetlands and their associated peat resources and applied it to a 1:24 000 scale map area in New Hampshire. Classifying and mapping wetlands involves integrating the spatial distribution of wetlands types with depth variations in associated peat quality and character. A hierarchically structured classification that integrates the spatial distribution of variations in (1) vegetation, (2) soil type, (3) hydrology, (4) geologic aspects, and (5) peat characteristics has been developed and can be used to build digital cartographic files for resource and land use analysis. The first three parameters are the bases used by the National Wetlands Inventory to classify wetlands and deepwater habitats of the United States. The fourth parameter, geological aspects, includes slope, relief, depth of wetland (from surface to underlying rock or substrate), wetland stratigraphy, and the type and structure of solid and unconsolidated rock surrounding and underlying the wetland. The fifth parameter, peat characteristics, includes the subsurface variation in ash, acidity, moisture, heating value (Btu), sulfur content, and other chemical properties as shown in specimens obtained from core holes. These parameters can be shown as a series of map data overlays with tables that can be integrated for resource or land use analysis.

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.

Organic Matter Transformation in the Peat Column at Marcell Experimental Forest: Humification and Vertical Stratification

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

Tfaily, Malak; Cooper, Bill; Kostka,

2014-01-01

A large-scale ecosystem manipulation (Spruce and Peatland Responses under Climatic and Environmental Change, SPRUCE) is being constructed in the Marcell Experimental Forest, Minnesota, USA, to determine the effects of climatic forcing on ecosystem processes in northern peatlands. Prior to the initiation of the manipulation, we characterized the solid-phase peat to a depth of 2 meters using a variety of techniques, including peat C:N ratios, 13C and 15N isotopic composition, Fourier Transform Infrared (FT IR), and 13C Nuclear Magnetic Resonance spectroscopy (13C NMR). FT IR determined peat humification-levels increased rapidly between and 75 cm, indicating a highly reactive zone. We observedmore » a rapid drop in the abundance of O-alkyl-C, carboxyl-C, and other oxygenated functionalities within this zone and a concomitant increase in the abundance of alkyl- and nitrogen-containing compounds. Below 75-cm, minimal change was observed except that aromatic functionalities accumulated with depth. Incubation studies revealed the highest methane production rates and greatest CH4:CO2 ratios within this and 75 cm zone. Hydrology and surface vegetation played a role in belowground carbon cycling. Radiocarbon signatures of microbial respiration products in deeper porewaters resembled the signatures of dissolved organic carbon rather than solid phase peat, indicating that more recently photosynthesized organic matter fueled the bulk of subsurface microbial respiration. Oxygen-containing functionalities, especially O-alkyl-C, appear to serve as an excellent proxy for soil decomposition rate, and in addition should be a sensitive indicator of the response of the solid phase peat to the climatic manipulation.« less

Shallow Ground-Water Flux Beneath a Restored Wetland Using Two-Dimensional Simulation of Ground-Water Flow and Heat Transport

NASA Astrophysics Data System (ADS)

Burow, K. R.; Gamble, J. M.; Fujii, R.; Constantz, J.

2001-12-01

Water flowing through the Sacramento-San Joaquin River Delta supplies drinking water to more than 20 million people in California. Delta water contains elevated concentrations of dissolved organic carbon (DOC) from drainage through the delta peat soils, forming trihalomethanes when the water is chlorinated for drinking. Land subsidence caused by oxidation of the peat soils has led to increased pumping of drainage water from delta islands to maintain arable land. An agricultural field on Twitchell Island was flooded in 1997 to evaluate continuous flooding as a technique to mitigate subsidence. The effects of shallow flooding on DOC loads to the drain water must be determined to evaluate the feasibility of this technique. In this study, heat is used as a nonconservative tracer to determine shallow ground-water flux and calculate DOC loads to an adjacent drainage ditch. Temperature profiles and water levels were measured in 12 wells installed beneath the pond, in the pond, and in an adjacent drainage ditch from May 2000 to June 2001. The range in seasonal temperatures decreased with depth, but seasonal temperature variation was evident in wells screened as deep as 10 to 12 feet below land surface. A constant temperature of 17 degrees C was measured in wells 25 feet beneath the pond. Ground-water flux beneath the pond was quantified in a two-dimensional simulation of water and heat exchange using the SUTRA flow and transport model. The effective vertical hydraulic conductivity of the peat soils underlying the pond was estimated through model calibration. Calibrated hydraulic conductivity is higher (1E-5 m/sec) than estimates from slug tests (2E-6 m/sec). Modeled pond seepage is similar to that estimated from a water budget, although the total seepage determined from the water budget is within the range of error of the instrumentation. Overall, model results indicate that recharge from the pond flows along shallow flow paths and that travel times through the peat to the drainage ditch may be on the order of decades.

Carbon Turnover in Organic Soils of Central Saskatchewan: Insights From a Core-Based Decomposition Study

NASA Astrophysics Data System (ADS)

Bauer, I. E.; Bhatti, J. S.; Hurdle, P. A.

2004-05-01

Field-based decomposition studies that examine several site types tend to use one of two approaches: Either the decay of one (or more) standard litters is examined in all sites, or litters native to each site type are incubated in the environment they came from. The first of these approaches examines effects of environment on decay, whereas the latter determines rates of mass loss characteristic of each site type. Both methods are usually restricted to a limited number of litters, and neither allows for a direct estimate of ecosystem-level parameters (e.g. heterotrophic respiration). In order to examine changes in total organic matter turnover along forest - peatland gradients in central Saskatchewan, we measured mass loss of native peat samples from six different depths (surface to 50 cm) over one year. Samples were obtained by sectioning short peat cores, and cores and samples were returned to their original position after determining the initial weight of each sample. A standard litter (birch popsicle sticks) was included at each depth, and water tables and soil temperature were monitored over the growing season. After one year, average mass loss in surface peat samples was similar to published values from litter bag studies, ranging from 12 to 21 percent in the environments examined. Native peat mass loss showed few systematic differences between sites or along the forest - peatland gradient, with over 60 percent of the total variability explained by depth alone. Mass loss of standard litter samples was highly variable, with high values in areas at the transition between upland and peatland that may have experienced recent disturbance. In combination, these results suggest strong litter-based control over natural rates of organic matter turnover. Estimates of heterotrophic respiration calculated from the mass loss data are higher than values obtained by eddy covariance or static chamber techniques, probably reflecting loss of material during the handling of samples or increased mass loss from manipulated profiles. Nevertheless, the core-based method is a useful tool in examining carbon dynamics of organic soils, since it provides a good relative index of organic matter turnover, and allows for separate examination of environmental and litter-based effects.

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 fluxes between hollow and hummock locations, δ13CH4 was more depleted in the early and late growing season, indicating a transition from hydrogenotrophic to acetoclastic methanogenesis during periods of high photosynthetic input.

Mobile geophysical study of peat deposits in Fuhrberger Field, Germany

NASA Astrophysics Data System (ADS)

Wunderlich, T.; Petersen, H.; Hagrey, S. A. al; Rabbel, W.

2012-04-01

In the water protection area of Fuhrberger Field, north of Hanover, geophysical techniques were applied to study the stakeholder problem of the source detection for nitrate accumulations in the ground water. We used our mobile multisensor platform to conduct measurements using Ground Penetrating Radar (GPR, 200 MHz antenna) and Electromagnetic Induction (EMI, EM31). This aims to study the subsurface occurrences of peat deposits (surplus of organic carbon) supposed to be a source of nitrate emissions due to the aeration and the drawdown of groundwater levels (e.g. by pumping, drainage etc.). Resulting EMI and GPR signals show high data quality. Measured apparent electrical conductivity shows very low values (<10 mS/m) due to the mainly sandy subsurface. For this medium, both methods are expected to penetrate down to 3-5 m depth. GPR radargrams, time slices of GPR reflection energy and EMI apparent electrical conductivities are plotted on aerial photographs and compared to each other's and with vegetation intensity. We could separate areas characterized by low reflection energy and high conductivity, and vice versa. Briefly, organic rich sediments such as peats are assumed to have a relative high conductivity and thus low GPR reflectivity. Some areas of local conductivity increase correspond to a deep reflection interface (as seen in the radargrams), which even vanishes due to the high attenuation caused by the high conductivity. This implies that the upper layer is more conductive than the lower layer. Several local areas with these characteristics are found at the study sites. We recommend shallow drillings at representative points to deliver the necessary confirmation with ground truth information. Acknowledgments: iSOIL (Interactions between soil related sciences - Linking geophysics, soil science and digital soil mapping) is a Collaborative Project (Grant Agreement number 211386) co-funded by the Research DG of the European Commission within the RTD activities of the FP7 Thematic Priority Environment.

N-15 NMR spectra of naturally abundant nitrogen in soil and aquatic natural organic matter samples of the International Humic Substances Society

USGS Publications Warehouse

Thorn, K.A.; Cox, L.G.

2009-01-01

The naturally abundant nitrogen in soil and aquatic NOM samples from the International Humic Substances Society has been characterized by solid state CP/MAS 15N NMR. Soil samples include humic and fulvic acids from the Elliot soil, Minnesota Waskish peat and Florida Pahokee peat, as well as the Summit Hill soil humic acid and the Leonardite humic acid. Aquatic samples include Suwannee River humic, fulvic and reverse osmosis isolates, Nordic humic and fulvic acids and Pony Lake fulvic acid. Additionally, Nordic and Suwannee River XAD-4 acids and Suwannee River hydrophobic neutral fractions were analyzed. Similar to literature reports, amide/aminoquinone nitrogens comprised the major peaks in the solid state spectra of the soil humic and fulvic acids, along with heterocyclic and amino sugar/terminal amino acid nitrogens. Spectra of aquatic samples, including the XAD-4 acids, contain resolved heterocyclic nitrogen peaks in addition to the amide nitrogens. The spectrum of the nitrogen enriched, microbially derived Pony Lake, Antarctica fulvic acid, appeared to contain resonances in the region of pyrazine, imine and/or pyridine nitrogens, which have not been observed previously in soil or aquatic humic substances by 15N NMR. Liquid state 15N NMR experiments were also recorded on the Elliot soil humic acid and Pony Lake fulvic acid, both to examine the feasibility of the techniques, and to determine whether improvements in resolution over the solid state could be realized. For both samples, polarization transfer (DEPT) and indirect detection (1H-15N gHSQC) spectra revealed greater resolution among nitrogens directly bonded to protons. The amide/aminoquinone nitrogens could also be observed by direct detection experiments.

N-15 NMR spectra of naturally abundant nitrogen in soil and aquatic natural organic matter samples of the International Humic Substances Society

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

Thorn, Kevin A.; Cox, Larry G.

2009-02-28

The naturally abundant nitrogen in soil and aquatic NOM samples from the International Humic Substances Society has been characterized by solid state CP/MAS ¹⁵N NMR. Soil samples include humic and fulvic acids from the Elliot soil, Minnesota Waskish peat and Florida Pahokee peat, as well as the Summit Hill soil humic acid and the Leonardite humic acid. Aquatic samples include Suwannee River humic, fulvic and reverse osmosis isolates, Nordic humic and fulvic acids and Pony Lake fulvic acid. Additionally, Nordic and Suwannee River XAD-4 acids and Suwannee River hydrophobic neutral fractions were analyzed. Similar to literature reports, amide/aminoquinone nitrogens comprisedmore » the major peaks in the solid state spectra of the soil humic and fulvic acids, along with heterocyclic and amino sugar/terminal amino acid nitrogens. Spectra of aquatic samples, including the XAD-4 acids, contain resolved heterocyclic nitrogen peaks in addition to the amide nitrogens. The spectrum of the nitrogen enriched, microbially derived Pony Lake, Antarctica fulvic acid, appeared to contain resonances in the region of pyrazine, imine and/or pyridine nitrogens, which have not been observed previously in soil or aquatic humic substances by ¹⁵N NMR. Liquid state ¹⁵N NMR experiments were also recorded on the Elliot soil humic acid and Pony Lake fulvic acid, both to examine the feasibility of the techniques, and to determine whether improvements in resolution over the solid state could be realized. For both samples, polarization transfer (DEPT) and indirect detection (¹H–¹⁵N gHSQC) spectra revealed greater resolution among nitrogens directly bonded to protons. The amide/aminoquinone nitrogens could also be observed by direct detection experiments.« less

Causes and effects of poor drainage in cranberry farms

USDA-ARS?s Scientific Manuscript database

Soils that support the growth of cranberries often cap geologic deposits of organic sediment, such as peat. However, low-permeability organic sediments may result in inadequate drainage that diminishes plant productivity and enhances fruit rot. Consequently, new constructions of cranberry farms are ...

Biochemical processes of oligotrophic peat deposits of Vasyugan Mire

NASA Astrophysics Data System (ADS)

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

2009-04-01

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

Global peatland initiation driven by regionally asynchronous warming.

PubMed

Morris, Paul J; Swindles, Graeme T; Valdes, Paul J; Ivanovic, Ruza F; Gregoire, Lauren J; Smith, Mark W; Tarasov, Lev; Haywood, Alan M; Bacon, Karen L

2018-05-08

Widespread establishment of peatlands since the Last Glacial Maximum represents the activation of a globally important carbon sink, but the drivers of peat initiation are unclear. The role of climate in peat initiation is particularly poorly understood. We used a general circulation model to simulate local changes in climate during the initiation of 1,097 peatlands around the world. We find that peat initiation in deglaciated landscapes in both hemispheres was driven primarily by warming growing seasons, likely through enhanced plant productivity, rather than by any increase in effective precipitation. In Western Siberia, which remained ice-free throughout the last glacial period, the initiation of the world's largest peatland complex was globally unique in that it was triggered by an increase in effective precipitation that inhibited soil respiration and allowed wetland plant communities to establish. Peat initiation in the tropics was only weakly related to climate change, and appears to have been driven primarily by nonclimatic mechanisms such as waterlogging due to tectonic subsidence. Our findings shed light on the genesis and Holocene climate space of one of the world's most carbon-dense ecosystem types, with implications for understanding trajectories of ecological change under changing future climates.

A method for measuring losses of soil carbon by heterotrophic respiration from peat soils under oil palms

NASA Astrophysics Data System (ADS)

Farmer, Jenny; Manning, Frances; Smith, Jo; Arn Teh, Yit

2017-04-01

The effects of drainage and deforestation of South East Asian peat swamp forests for the development of oil palm plantations has received considerable attention in both mainstream media and academia, and is the source of significant discussion and debate. However, data on the long-term carbon losses from these peat soils as a result of this land use change is still limited and the methods with which to collect this data are still developing. Here we present the ongoing evolution and implementation of a method for separating autotrophic and heterotrophic respiration by sampling carbon dioxide emissions at increasing distance from palm trees. We present the limitations of the method, modelling approaches and results from our studies. In 2011 we trialled this method in Sumatra, Indonesia and collected rate measurements over a six day period in three ages of oil palm. In the four year oil palm site there were thirteen collars that had no roots present and from these the peat based carbon losses were recorded to be 0.44 g CO2 m2 hr-1 [0.34; 0.57] (equivalent to 39 t CO2 ha-1 yr-1 [30; 50]) with a mean water table depth of 0.40 m, or 63% of the measured total respiration across the plot. In the two older palm sites of six and seven years, only one collar out of 100 had no roots present, and thus a linear random effects model was developed to calculate heterotrophic emissions for different distances from the palm tree. This model suggested that heterotrophic respiration was between 37 - 59% of total respiration in the six year old plantation and 39 - 56% in the seven year old plantation. We applied this method in 2014 to a seven year old plantation, in Sarawak, Malaysia, modifying the method to include the heterotrophic contribution from beneath frond piles and weed covered areas. These results indicated peat based carbon losses to be 0.42 g CO2 m2 hr-1 [0.27;0.59] (equivalent to 37 t CO2 ha-1 yr-1 [24; 52]) at an average water table depth of 0.35 m, 47% of the measured total respiration of the plot. We conclude that, despite a few limitations, it is possible to use a linear modelling approach to partition heterotrophic respiration from the total respiration in oil palm plantations.

Subsidence due to peat oxidation and impact on drainage infrastructures in a farmland catchment south of the Venice Lagoon

NASA Astrophysics Data System (ADS)

Gambolati, G.; Putti, M.; Teatini, P.; Gasparetto Stori, G.

2006-03-01

Large agricultural areas reclaimed in the past century, south of the Venice Lagoon, have experienced significant land subsidence due to oxidation of peat organic soils. This has exposed the region to flood hazard particularly during severe storms and has contributed to increase the marginal management cost of the infrastructures (ditches, levees, pumping stations) designed to operate the drainage system. Direct measurements and indirect evidence from the channel network suggest a land settlement between 1.5 and 2 m over the past 70 years. This paper provides an overview of the problem with important information on its most recent evolution.

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

NASA Astrophysics Data System (ADS)

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

2015-04-01

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

Greenhouse gas efflux from an impacted Malaysian tropical peat swamp (Invited)

NASA Astrophysics Data System (ADS)

Waldron, S.; Vihermaa, L. E.; Evers, S.; Garnett, M.; Newton, J.; Padfield, R.

2013-12-01

Tropical peatlands constitute ~11% of global peatland area and ~12% of the global peat C pool. Malaysia alone contains 10% of tropical peats. Due to rising global demands for food and biofuels, SE-Asia peat swamp forest ecosystems are threatened by increasing amounts of drainage, fire and conversion to plantation. These processes can change the GHG emissions and thus net ecosystem C balance. However, in comparison to temperate and boreal peatlands, there is a lack of data on terrestrial-aquatic-atmospheric carbon transfer from tropical peatlands, both those that are little disturbed and those facing anthropogenic pressures. Lateral transport of soil-respired carbon, and fluvial respiration or UV-oxidation of terrestrial DOC primes atmospheric carbon dioxide efflux. We now know that DOC lost from disturbed tropical peat swamp forests can be centuries to millennia old and originates deep within the peat column - this carbon may fuel efflux of old carbon dioxide and so anthropogenic land-use change renders the older, slower carbon cycles shorter and faster. Currently we have no knowledge of how significant ';older-slower' terrestrial-aquatic-atmospheric cycles are in disturbed tropical peatlands. Further, in some areas for commercial reasons, or by conservation bodies trying to minimise peat habitat loss, logged peats have been left to regenerate. Consequently, unpicking the legacy of multiple land uses on magnitude, age and source of GHG emissions is challenging but required to support land management decisions and projections of response to a changing climate. Here, we present the results of our first field campaign in July 2013 to the Raja Musa and Sungai Karang Peat Swamp Forest Reserves in North Selangor, Malaysia. This is one of Malaysia's largest oceanic peat swamps, and has been selectively logged and drained for 80 years, but is now subject to a 30 year logging ban to aid forest regeneration and build up wood stocks. From sites subject to different land use, we will present measurements of i) spatial variation in fluvial carbon dioxide and methane concentrations and associated efflux rates, and ii) the stable carbon isotopic composition of DIC and novel determination of the age of the effluxed carbon dioxide. From this we can consider if younger-faster or older-slower carbon cycling dominates the terrestrial-aquatic-atmospheric C transfer during this dry period sampling.

Geophysical surveying in the Sacramento Delta for earthquake hazard assessment and measurement of peat thickness

NASA Astrophysics Data System (ADS)

Craig, M. S.; Kundariya, N.; Hayashi, K.; Srinivas, A.; Burnham, M.; Oikawa, P.

2017-12-01

Near surface geophysical surveys were conducted in the Sacramento-San Joaquin Delta for earthquake hazard assessment and to provide estimates of peat thickness for use in carbon models. Delta islands have experienced 3-8 meters of subsidence during the past century due to oxidation and compaction of peat. Projected sea level rise over the next century will contribute to an ongoing landward shift of the freshwater-saltwater interface, and increase the risk of flooding due to levee failure or overtopping. Seismic shear wave velocity (VS) was measured in the upper 30 meters to determine Uniform Building Code (UBC)/ National Earthquake Hazard Reduction Program (NEHRP) site class. Both seismic and ground penetrating radar (GPR) methods were employed to estimate peat thickness. Seismic surface wave surveys were conducted at eight sites on three islands and GPR surveys were conducted at two of the sites. Combined with sites surveyed in 2015, the new work brings the total number of sites surveyed in the Delta to twenty.Soil boreholes were made at several locations using a hand auger, and peat thickness ranged from 2.1 to 5.5 meters. Seismic surveys were conducted using the multichannel analysis of surface wave (MASW) method and the microtremor array method (MAM). On Bouldin Island, VS of the surficial peat layer was 32 m/s at a site with pure peat and 63 m/s at a site peat with higher clay and silt content. Velocities at these sites reached a similar value, about 125 m/s, at a depth of 10 m. GPR surveys were performed at two sites on Sherman Island using 100 MHz antennas, and indicated the base of the peat layer at a depth of about 4 meters, consistent with nearby auger holes.The results of this work include VS depth profiles and UBC/NEHRP site classifications. Seismic and GPR methods may be used in a complementary fashion to estimate peat thickness. The seismic surface wave method is a relatively robust method and more effective than GPR in many areas with high clay content or where surface sediments have been disturbed by human activities. GPR does however provide significantly higher resolution and better depth control in areas with suitable recording conditions.

Hydrologic processes governing near surface saturation of alpine wetlands in the Canadian Rockies

NASA Astrophysics Data System (ADS)

Westbrook, C.; Mercer, J.

2016-12-01

Alpine wetlands are vital for habitat, biodiversity, carbon cycling and water storage, but little is known about their hydrologic condition. Climate trends toward smaller mountain snowpacks that melt earlier are thought to pose a threat to the continued provision of alpine wetland ecological functions, and their existence, as it is believed they derive their water mainly from snowmelt. Our objective was to determine the hydrologic processes governing near surface saturation in alpine wetlands. We monitored the water table dynamics of three alpine wetlands in contrasting hydrogeomorphic landscape positions for two summers in Banff National Park, Canada. We concurrently monitored water balance components, and analyzed soil properties and source water geochemistry. Despite very different snow conditions between the two study years, water tables remained near the surface and relatively stable in both years, indicating wetlands are more hydrologically buffered from snowpack variations than expected. We did not find convincing evidence of hydrogeomorphic position influencing wetland water table dynamics. Instead, peat thickness seemed to be critical in regulating water table as the wetland with the thickest peat soil (>1 m) maintained water tables closest to the ground surface for the longest period of time. Thicker peat deposits may develop under convergent hydrologic flow path conditions. Our results indicate that alpine wetlands are more resilient to shifting environmental conditions than previously reported.

Cultivation of a bacterial consortium with the potential to degrade total petroleum hydrocarbon using waste activated sludge.

PubMed

Sivakumar, S; Song, Y C; Kim, S H; Jang, S H

2015-11-01

Waste activated sludge was aerobically treated to demonstrate multiple uses such as cultivating an oil degrading bacterial consortium; studying the influence of a bulking agent (peat moss) and total petroleum hydrocarbon concentration on bacterial growth and producing a soil conditioner using waste activated sludge. After 30 days of incubation, the concentration of oil-degrading bacteria was 4.3 x 10(8) CFU g(-1) and 4.5 x 10(8) CFU g(-1) for 5 and 10 g of total petroleum hydrocarbon, respectively, in a mixture of waste activated sludge (1 kg) and peat moss (0.1 kg). This accounts for approximately 88.4 and 91.1%, respectively, of the total heterotrophic bacteria (total-HB). The addition of bulking agent enhanced total-HB population and total petroleum hydrocarbon-degrading bacterial population. Over 90% of total petroleum hydrocarbon degradation was achieved by the mixture of waste activated sludge, bulking agent and total petroleum hydrocarbon. The results of physico-chemical parameters of the compost (waste activated sludge with and without added peat moss compost) and a substantial reduction in E. coli showed that the use of this final product did not exhibit risk when used as soil conditioner. Finally, the present study demonstrated that cultivation of total petroleum hydrocarbon-degrading bacterial consortium and production of compost from waste activated sludge by aerobic treatment was feasible.

Nitrate turnover in a peat soil under drained and rewetted conditions: results from a [(15)N]nitrate-bromide double-tracer study.

PubMed

Russow, Rolf; Tauchnitz, Nadine; Spott, Oliver; Mothes, Sibylle; Bernsdorf, Sabine; Meissner, Ralph

2013-01-01

Under natural conditions, peatlands are generally nitrate-limited. However, recent concerns about an additional N input into peatlands by atmospheric N deposition have highlighted the risk of an increased denitrification activity and hence the likelihood of a rise of emissions of the greenhouse gas nitrous oxide. Therefore, the aim of the present study was to investigate the turnover of added nitrate in a drained and a rewetted peatland using a [(15)N]nitrate-bromide double-tracer method. The double-tracer method allows a separation between physical effects (dilution, dispersion and dislocation) and microbial and chemical nitrate transformation by comparing with the conservative Br(-) tracer. In the drained peat site, low NO3(-) consumption rates have been observed. In contrast, NO3(-) consumption at the rewetted peat site rises rapidly to about 100% within 4 days after tracer application. Concomitantly, the (15)N abundances of nitrite and ammonium in soil water increased and lead to the conclusion that, besides commonly known NO3(-) reduction to nitrite (i.e. denitrification), a dissimilatory nitrate reduction to ammonium has simultaneously taken place. The present study reveals that increasing NO3(-) inputs into rewetted peatlands via atmospheric deposition results in a rapid NO3(-) consumption, which could lead to an increase in N2O emissions into the atmosphere.

Effects of polar and nonpolar groups on the solubility of organic compounds in soil organic matter

USGS Publications Warehouse

Chiou, C.T.; Kile, D.E.

1994-01-01

Vapor sorption capacities on a high-organic-content peat, a model for soil organic matter (SOM), were determined at room temperature for the following liquids: n-hexane, 1,4-dioxane, nitroethane, acetone, acetonitrile, 1-propanol, ethanol, and methanol. The linear organic vapor sorption is in keeping with the dominance of vapor partition in peat SOM. These data and similar results of carbon tetrachloride (CT), trichloroethylene (TCE), benzene, ethylene glycol monoethyl ether (EGME), and water on the same peat from earlier studies are used to evaluate the effect of polarity on the vapor partition in SOM. The extrapolated liquid solubility from the vapor isotherm increases sharply from 3-6 wt % for low-polarity liquids (hexane, CT, and benzene) to 62 wt % for polar methanol and correlates positively with the liquid's component solubility parameters for polar interaction (??P) and hydrogen bonding (??h). The same polarity effect may be expected to influence the relative solubilities of a variety of contaminants in SOM and, therefore, the relative deviations between the SOM-water partition coefficients (Kom) and corresponding octanol-water partition coefficients (Kow) for different classes of compounds. The large solubility disparity in SOM between polar and nonpolar solutes suggests that the accurate prediction of Kom from Kow or Sw (solute water solubility) would be limited to compounds of similar polarity.

Quantifying soil carbon accumulation in Alaskan terrestrial ecosystems during the last 15 000 years

DOE PAGES

Wang, Sirui; Zhuang, Qianlai; Yu, Zicheng

2016-11-25

Northern high latitudes contain large amounts of soil organic carbon (SOC), of which Alaskan terrestrial ecosystems account for a substantial proportion. In this study, the SOC accumulation in Alaskan terrestrial ecosystems over the last 15 000 years was simulated using a process-based biogeochemistry model for both peatland and non-peatland ecosystems. Comparable with the previous estimates of 25–70 Pg C in peatland and 13–22 Pg C in non-peatland soils within 1 m depth in Alaska using peat-core data, our model estimated a total SOC of 36–63 Pg C at present, including 27–48 Pg C in peatland soils and 9–15 Pg C in non-peatland soils. Current vegetation stored 2.5–3.7 Pg C in Alaska, with 0.3–0.6 Pg C in peatlandsmore » and 2.2–3.1 Pg C in non-peatlands. The simulated average rate of peat C accumulation was 2.3 Tg C yr −1, with a peak value of 5.1 Tg C yr −1 during the Holocene Thermal Maximum (HTM) in the early Holocene, 4-fold higher than the average rate of 1.4 Tg C yr −1 over the rest of the Holocene. The SOC accumulation slowed down, or even ceased, during the neoglacial climate cooling after the mid-Holocene, but increased again in the 20th century. The model-estimated peat depths ranged from 1.1 to 2.7 m, similar to the field-based estimate of 2.29 m for the region. We found that the changes in vegetation and their distributions were the main factors in determining the spatial variations of SOC accumulation during different time periods. Warmer summer temperature and stronger radiation seasonality, along with higher precipitation in the HTM and the 20th century, might have resulted in the extensive peatland expansion and carbon accumulation.« less

Quantifying soil carbon accumulation in Alaskan terrestrial ecosystems during the last 15 000 years

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

Wang, Sirui; Zhuang, Qianlai; Yu, Zicheng

Northern high latitudes contain large amounts of soil organic carbon (SOC), of which Alaskan terrestrial ecosystems account for a substantial proportion. In this study, the SOC accumulation in Alaskan terrestrial ecosystems over the last 15 000 years was simulated using a process-based biogeochemistry model for both peatland and non-peatland ecosystems. Comparable with the previous estimates of 25–70 Pg C in peatland and 13–22 Pg C in non-peatland soils within 1 m depth in Alaska using peat-core data, our model estimated a total SOC of 36–63 Pg C at present, including 27–48 Pg C in peatland soils and 9–15 Pg C in non-peatland soils. Current vegetation stored 2.5–3.7 Pg C in Alaska, with 0.3–0.6 Pg C in peatlandsmore » and 2.2–3.1 Pg C in non-peatlands. The simulated average rate of peat C accumulation was 2.3 Tg C yr −1, with a peak value of 5.1 Tg C yr −1 during the Holocene Thermal Maximum (HTM) in the early Holocene, 4-fold higher than the average rate of 1.4 Tg C yr −1 over the rest of the Holocene. The SOC accumulation slowed down, or even ceased, during the neoglacial climate cooling after the mid-Holocene, but increased again in the 20th century. The model-estimated peat depths ranged from 1.1 to 2.7 m, similar to the field-based estimate of 2.29 m for the region. We found that the changes in vegetation and their distributions were the main factors in determining the spatial variations of SOC accumulation during different time periods. Warmer summer temperature and stronger radiation seasonality, along with higher precipitation in the HTM and the 20th century, might have resulted in the extensive peatland expansion and carbon accumulation.« less

Carbon balance of a fertile forestry-drained peatland in southern Finland

NASA Astrophysics Data System (ADS)

Lohila, Annalea; Korkiakoski, Mika; Tuovinen, Juha-Pekka; Minkkinen, Kari; Penttilä, Timo; Ojanen, Paavo; Launiainen, Samuli; Laurila, Tuomas

2016-04-01

Forestry on peatlands is a significant land use form and has been economically important during the last decades particularly in the Nordic countries. While nutrient-poor forests are generally able to maintain their carbon sink status even after drainage, the peat soil at the fertile sites is typically considered as a large carbon dioxide (CO2) source. This means that despite of high timber production capacity, the fertile peatland forests gradually lose their peat carbon store. In addition, many of the nutrient-rich sites emit considerable amount of nitrous oxide (N2O) into the atmosphere. While the current estimates of the greenhouse gas (GHG) balance of forestry-drained peatlands are largely based on soil inventories or on data combining soil GHG fluxes and tree growth litter input measurements and modelling, only few studies have utilized the high-resolution, continuous eddy covariance (EC) data to address the short-term dynamics of the net CO2 fluxes covering both the soil, forest floor vegetation and the trees. Hence, little is known about the factors which control the year-to-year variation in fluxes. Here we present a 5-year dataset of CO2 fluxes measured with the EC method above a nutrient-rich forestry-drained peatland in southern Finland. The site, drained in the beginning of 1970's, is a well growing pine forest with some spruces and birches, the tree volume and carbon fixation rate equaling 8.0 kg C m-2 and 0.273 kg C m-2 yr-1, respectively. The average summer-time water level depth is -50 cm. By combining the gap-filled half-hourly net ecosystem exchange (NEE) data, the tree growth measurements, and the measurements on dissolved organic carbon (DOC) losses and soil methane (CH4) exchange, we will in this presentation estimate the total annual loss of peat carbon of this fertile peatland forest. In addition, using the N2O flux data we will estimate the contribution of different gases to the total GHG balance. Factors controlling the carbon balance and its seasonal and inter-annual variation are discussed.

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

NASA Astrophysics Data System (ADS)

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

2003-04-01

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

Consortia of low-abundance bacteria drive sulfate reduction-dependent degradation of fermentation products in peat soil microcosms

DOE PAGES

Hausmann, Bela; Knorr, Klaus-Holger; Schreck, Katharina; ...

2016-03-25

A cryptic sulfur cycle and effectively competes with methanogenic degradation pathways sustains dissimilatory sulfate reduction in peatlands. In a series of peat soil microcosms incubated over 50 days, we identified bacterial consortia that responded to small, periodic additions of individual fermentation products (formate, acetate, propionate, lactate or butyrate) in the presence or absence of sulfate. Under sulfate supplementation, net sulfate turnover (ST) steadily increased to 16–174 nmol cm –3 per day and almost completely blocked methanogenesis. 16S rRNA gene and cDNA amplicon sequencing identified microorganisms whose increases in ribosome numbers strongly correlated to ST. Natively abundant (greater than or equalmore » to0.1% estimated genome abundance) species-level operational taxonomic units (OTUs) showed no significant response to sulfate. In contrast, low-abundance OTUs responded significantly to sulfate in incubations with propionate, lactate and butyrate. These OTUs included members of recognized sulfate-reducing taxa (Desulfosporosinus, Desulfopila, Desulfomonile, Desulfovibrio) and also members of taxa that are either yet unknown sulfate reducers or metabolic interaction partners thereof. The most responsive OTUs markedly increased their ribosome content but only weakly increased in abundance. Responsive Desulfosporosinus OTUs even maintained a constantly low population size throughout 50 days, which suggests a novel strategy of rare biosphere members to display activity. Interestingly, two OTUs of the non-sulfate-reducing genus Telmatospirillum (Alphaproteobacteria) showed strongly contrasting preferences towards sulfate in butyrate-amended microcosms, corroborating that closely related microorganisms are not necessarily ecologically coherent. We show that diverse consortia of low-abundance microorganisms can perform peat soil sulfate reduction, a process that exerts control on methane production in these climate-relevant ecosystems.« less

Adaptation of biomixtures for carbofuran degradation in on-farm biopurification systems in tropical regions.

PubMed

Chin-Pampillo, Juan Salvador; Ruiz-Hidalgo, Karla; Masís-Mora, Mario; Carazo-Rojas, Elizabeth; Rodríguez-Rodríguez, Carlos E

2015-07-01

A biomixture constitutes the active core of the on-farm biopurification systems, employed for the detoxification of pesticide-containing wastewaters. As biomixtures should be prepared considering the available local materials, the present work aimed to evaluate the performance of ten different biomixtures elaborated with by-products from local farming, in the degradation of the insecticide/nematicide carbofuran (CFN), in order to identify suitable autochthonous biomixtures to be used in the tropics. Five different lignocellulosic materials mixed with either compost or peat and soil were employed in the preparation of the biomixtures. The comprehensive evaluation of the biomixtures included removal of the parent compound, formation of transformation products, mineralization of radiolabeled CFN, and determination of the residual toxicity of the process. Detoxification capacity of the matrices was high, and compost-based biomixtures showed better performance than peat-based biomixtures. CFN removal over 98.5% was achieved within 16 days (eight out of ten biomixtures), with half-lives below 5 days in most of the cases. 3-Hydroxycarbofuran and 3-ketocarbofuran were found as transformation products at very low concentrations suggesting their further degradation. Mineralization of CFN was also achieved after 64 days (2.9 to 15.1%); several biomixtures presented higher mineralization than the soil itself. Acute toxicity determinations with Daphnia magna revealed a marked detoxification in the matrices at the end of the process; low residual toxicity was observed only in two of the peat-based biomixtures. Overall best efficiency was achieved with the biomixture composed of coconut fiber-compost-soil; however, results suggest that in the case of unavailability of coconut fiber, other biomixtures may be employed with similar performance.

Time-Lapse Geophysical Measurements targeting Spatial and Temporal Variability in Biogenic Gas Production from Peat Soils in a Hydrologically Controlled Wetland in the Florida Everglades

NASA Astrophysics Data System (ADS)

Wright, W. J.; Shahan, T.; Sharp, N.; Comas, X.

2015-12-01

Peat soils are known to release globally significant amounts of methane (CH4) and carbon dioxide (CO2) to the atmosphere. However, uncertainties still remain regarding the spatio-temporal distribution of gas accumulations and triggering mechanisms of gas releasing events. Furthermore, most research on peatland gas dynamics has traditionally been focused on high latitude peatlands. Therefore, understanding gas dynamics in low-latitude peatlands (e.g. the Florida Everglades) is key to global climate research. Recent studies in the Everglades have demonstrated that biogenic gas flux values may vary when considering different temporal and spatial scales of measurements. The work presented here targets spatial variability in gas production and release at the plot scale in an approximately 85 m2 area, and targets temporal variability with data collected during the spring months of two different years. This study is located in the Loxahatchee Impoundment Landscape Assessment (LILA), a hydrologically controlled, landscape scale (30 Ha) model of the Florida Everglades. Ground penetrating radar (GPR) has been used in the past to investigate biogenic gas dynamics in peat soils, and is used in this study to monitor changes of in situ gas storage. Each year, a grid of GPR profiles was collected to image changes in gas distribution in 2d on a weekly basis, and several flux chambers outfitted with time-lapse cameras captured high resolution (hourly) gas flux measurements inside the GPR grid. Combining these methods allows us to use a mass balance approach to estimate spatial variability in gas production rates, and capture temporal variability in gas flux rates.

Heterotrophic respiration in drained tropical peat temperatures influenced by shading gradient

NASA Astrophysics Data System (ADS)

Jauhiainen, Jyrki; Kerojoki, Otto; Silvennoinen, Hanna; Limin, Suwido; Vasander, Harri

2015-04-01

Lowland peatlands in Southeast Asia constitute a highly concentrated carbon (C) pool of global significance. These peatlands have formed over periods of several millennia by forest vegetation tolerant to flooding and poor substrates. Uncontrollable drainage and reoccurring wild fires in lack of management after removal of forest cover has impaired the C-storing functions in large reclaimed areas. Intergovernmental Panel on Climate Change (IPCC) reporting sees drained tropical organic soils as one of the largest greenhouse gas emissions releasing terrestrial systems. Vast areas of deforested tropical peatlands do not receive noteworthy shading by vegetation, which increases the amount of solar radiation reaching the peat surface. We studied heterotrophic carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) fluxes in tropical peat in conditions, where; (i) peat temperatures were modified by artificial shading (no shade, 28%, 51% and 90% from the full sun exposure), (ii) root respiration was minimized, (iii) nutrient availability for peat decomposer community was changed (NPK fertilization of 0 and 313 kg ha-1). The experiment was repeated at two over 20 years ago drained fallow agricultural- and degraded sites in Central Kalimantan, Indonesia. Enhanced shading created a lasting decrease in peat temperatures, and decreased diurnal temperature fluctuations, in comparison to less shaded plots. The largest peat temperature difference was between the unshaded and 90% shaded peat surface, where the average temperatures within the topmost 50-cm peat profile differed 3 °C, and diurnal temperatures at 5 cm depth varied up to 4.2 °C in the unshaded and 0.4 °C in the 90% shaded conditions. Highest impacts on the heterotrophic CO2 fluxes caused by the treatments were on agricultural land, where 90% shading from the full exposure resulted in a 33% lower CO2 emission average on the unfertilised plots and a 66% lower emission average on the fertilised plots. Correlation between peat temperature and CO2 flux suggested an approximately 8% (unfertilised) and 25% (fertilised) emissions change for each 1 °C temperature change at 5 cm depth on the agricultural land. CO2 flux responses to the treatments remained low or were inconsistent over the peat temperature range.. Fertilised conditions negatively correlated with N2O efflux with increases in temperature, suggesting a 12-36% lower efflux for each 1 °C increase in peat temperature (at 5 cm depth) at the sites. Despite the apparently similar landscapes of fallow agricultural land and degraded peatland sites, the differences in greenhouse gas dynamics are expected to be an outcome of the long-term management differences. Based on the results it is possible to seek management practices that prolong timespan for using drained tropical peat for cultivation, simultaneously reduce negative climate impacts created from peat substrate carbon loss, and also improve greenhouse gas monitoring techniques at field.

Reorganization of vegetation, hydrology and soil carbon after permafrost degradation across heterogeneous boreal landscapes

USGS Publications Warehouse

Jorgenson, M. Torre; Harden, Jennifer; Kanevskiy, Mikhail; O'Donnell, Jonathan; Wickland, Kim; Ewing, Stephanie; Manies, Kristen; Zhuang, Qianlai; Shur, Yuri; Striegl, Robert G.; Koch, Joshua C.

2013-01-01

The diversity of ecosystems across boreal landscapes, successional changes after disturbance and complicated permafrost histories, present enormous challenges for assessing how vegetation, water and soil carbon may respond to climate change in boreal regions. To address this complexity, we used a chronosequence approach to assess changes in vegetation composition, water storage and soil organic carbon (SOC) stocks along successional gradients within four landscapes: (1) rocky uplands on ice-poor hillside colluvium, (2) silty uplands on extremely ice-rich loess, (3) gravelly–sandy lowlands on ice-poor eolian sand and (4) peaty–silty lowlands on thick ice-rich peat deposits over reworked lowland loess. In rocky uplands, after fire permafrost thawed rapidly due to low ice contents, soils became well drained and SOC stocks decreased slightly. In silty uplands, after fire permafrost persisted, soils remained saturated and SOC decreased slightly. In gravelly–sandy lowlands where permafrost persisted in drier forest soils, loss of deeper permafrost around lakes has allowed recent widespread drainage of lakes that has exposed limnic material with high SOC to aerobic decomposition. In peaty–silty lowlands, 2–4 m of thaw settlement led to fragmented drainage patterns in isolated thermokarst bogs and flooding of soils, and surface soils accumulated new bog peat. We were not able to detect SOC changes in deeper soils, however, due to high variability. Complicated soil stratigraphy revealed that permafrost has repeatedly aggraded and degraded in all landscapes during the Holocene, although in silty uplands only the upper permafrost was affected. Overall, permafrost thaw has led to the reorganization of vegetation, water storage and flow paths, and patterns of SOC accumulation. However, changes have occurred over different timescales among landscapes: over decades in rocky uplands and gravelly–sandy lowlands in response to fire and lake drainage, over decades to centuries in peaty–silty lowlands with a legacy of complicated Holocene changes, and over centuries in silty uplands where ice-rich soil and ecological recovery protect permafrost.

Prediction of the effects of soil-based countermeasures on soil solution chemistry of soils contaminated with radiocesium using the hydrogeochemical code PHREEQC.

PubMed

Hormann, Volker; Kirchner, Gerald

2002-04-22

For agriculturally used areas, which are contaminated by the debris from a nuclear accident, the use of chemical amendmends (e.g. potassium chloride and lime) is among the most common soil-based countermeasures. These countermeasures are intended to reduce the plant uptake of radionuclides (mainly 137Cs and 90Sr) by competitive inhibition by chemically similar ions. So far, the impacts of countermeasures on soil solution composition - and thus, their effectiveness - have almost exclusively been established experimentally, since they depend on mineral composition and chemical characteristics of the soil affected. In this study, which focuses on caesium contamination, the well-established code PHREEQC was used as a geochemical model to calculate the changes in the ionic compositions of soil solutions, which result from the application of potassium or ammonium in batch equilibrium experiments. The simple ion exchange model used by PHREEQC was improved by taking into account selective sorption of Cs+, NH4+ and K+ by clay minerals. Calculations were performed with three different initial soil solution compositions, corresponding to particular soil types (loam, sand, peat). For loamy and sandy soils, our calculational results agree well with experimental data reported by Nisbet (Effectiveness of soil-based countermeasures six months and one year after contamination of five diverse soil types with caesium-134 and strontium-90. Contract Report NRPB-M546, National Radiation Protection Board, Chilton, 1995.). For peat, discrepancies were found indicating that for organic soils a reliable set of exchange constants of the relevant cations still has to be determined experimentally. For cesium, however, these discrepancies almost disappeared if selective sites were assumed to be inaccessible. Additionally, results of sensitivity analyses are presented by which the influence of the main soil parameters on Cs+ concentrations in solution after soil treatment has been systematically studied. It is shown that calculating the impacts of soil-based chemical countermeasures on soil solution chemistry using geochemical codes such as PHREEQC offers an attractive alternative to establishing these impacts by often time-consuming and site-specific experiments.

Effects of Eriophorum vaginatum on N_{2}O emissions at a restored peatland

NASA Astrophysics Data System (ADS)

Brummell, Martin; Lazcano, Cristina; Strack, Maria

2016-04-01

Restoration of peatlands extracted for horticultural peat production includes both deliberate and accidental introduction of a wide range of plant species, including vascular plants and bryophytes. The roots of vascular plants provide a channel for the movement of greenhouse gases (GHG) including N2O in many soil ecosystems, and may stimulate production of N2O or have other effects via the release of root exudates that are then taken up by soil microorganisms such as heterotrophic denitrifiers. Here we carried out a field study in order to evaluate the effects of Eriophorum vaginatum, an abundant sedge at the harvested peatland at Seba Beach, Alberta, Canada, (53° 27'17.2"N 114° 52'52.0"W) where restoration efforts began in late 2012, and is the dominant ground cover in some areas. We hypothesized that E. vaginatum would increase net N2O production from peat compared to areas of bare peat or moss. We measured net GHG exchange for CO2, CH4, and N2O over one growing season (May-September 2015) using static chambers within this peatland to compare between plots containing E. vaginatum and plots lacking vascular plants. Plots were located along a transect of increasing water table, in order to discriminate between the effects of E. vaginatum and the prevailing hydrological conditions on N2O fluxes. Net fluxes of N2O from the peat to the atmosphere were observed throughout the experimental area, as well as fluxes in the opposite direction, in which the peat removed N2O from the atmosphere inside the chamber. Non-zero fluxes were highly variable in both occurrence and magnitude, though a small number of plots accounted for the majority of measured fluxes. Neither aboveground biomass of E. vaginatum nor its presence in a plot was correlated with either frequency or direction of N2O flux measurements. Other factors, such as water table fluctuations and temperature may be stronger drivers of these microbially-mediated processes than vegetation at this stage of the restoration.

MOELCULAR SIZE EXCLUSION BY SOIL ORGANIC MATERIALS ESTIMATED FROM THEIR SWELLING IN ORGANIC SOLVENTS

EPA Science Inventory

A published method previously developed to measure the swelling characteristics of pow dered coal samples has been adapted for swelling measurements on various peat, pollen, chain, and cellulose samples The swelling of these macromolecular materials is the volumetric manifestatio...

MOLECULAR SIZE EXCLUSION BY SOIL ORGANIC MATERIALS ESTIMATED FROM THEIR SWELLING IN ORGANIC SOLVENTS

EPA Science Inventory

A published method previously developed to measure the swelling characteristics of powdered coal samples has been adapted for swelling measurements on various peat, pollen, chitin, and cellulose samples. he swelling of these macromolecular materials is the volumetric manifestatio...

Assessment of potential climate change impacts on peatland dissolved organic carbon release and drinking water treatment from laboratory experiments.

PubMed

Tang, R; Clark, J M; Bond, T; Graham, N; Hughes, D; Freeman, C

2013-02-01

Catchments draining peat soils provide the majority of drinking water in the UK. Over the past decades, concentrations of dissolved organic carbon (DOC) have increased in surface waters. Residual DOC can cause harmful carcinogenic disinfection by-products to form during water treatment processes. Increased frequency and severity of droughts combined with and increased temperatures expected as the climate changes, have potentials to change water quality. We used a novel approach to investigate links between climate change, DOC release and subsequent effects on drinking water treatment. We designed a climate manipulation experiment to simulate projected climate changes and monitored releases from peat soil and litter, then simulated coagulation used in water treatment. We showed that the 'drought' simulation was the dominant factor altering DOC release and affected the ability to remove DOC. Our results imply that future short-term drought events could have a greater impact than increased temperature on DOC treatability. Copyright © 2012 Elsevier Ltd. All rights reserved.

Carbon stocks and fluxes in the high latitudes: using site-level data to evaluate Earth system models

NASA Astrophysics Data System (ADS)

Chadburn, Sarah E.; Krinner, Gerhard; Porada, Philipp; Bartsch, Annett; Beer, Christian; Belelli Marchesini, Luca; Boike, Julia; Ekici, Altug; Elberling, Bo; Friborg, Thomas; Hugelius, Gustaf; Johansson, Margareta; Kuhry, Peter; Kutzbach, Lars; Langer, Moritz; Lund, Magnus; Parmentier, Frans-Jan W.; Peng, Shushi; Van Huissteden, Ko; Wang, Tao; Westermann, Sebastian; Zhu, Dan; Burke, Eleanor J.

2017-11-01

It is important that climate models can accurately simulate the terrestrial carbon cycle in the Arctic due to the large and potentially labile carbon stocks found in permafrost-affected environments, which can lead to a positive climate feedback, along with the possibility of future carbon sinks from northward expansion of vegetation under climate warming. Here we evaluate the simulation of tundra carbon stocks and fluxes in three land surface schemes that each form part of major Earth system models (JSBACH, Germany; JULES, UK; ORCHIDEE, France). We use a site-level approach in which comprehensive, high-frequency datasets allow us to disentangle the importance of different processes. The models have improved physical permafrost processes and there is a reasonable correspondence between the simulated and measured physical variables, including soil temperature, soil moisture and snow. We show that if the models simulate the correct leaf area index (LAI), the standard C3 photosynthesis schemes produce the correct order of magnitude of carbon fluxes. Therefore, simulating the correct LAI is one of the first priorities. LAI depends quite strongly on climatic variables alone, as we see by the fact that the dynamic vegetation model can simulate most of the differences in LAI between sites, based almost entirely on climate inputs. However, we also identify an influence from nutrient limitation as the LAI becomes too large at some of the more nutrient-limited sites. We conclude that including moss as well as vascular plants is of primary importance to the carbon budget, as moss contributes a large fraction to the seasonal CO2 flux in nutrient-limited conditions. Moss photosynthetic activity can be strongly influenced by the moisture content of moss, and the carbon uptake can be significantly different from vascular plants with a similar LAI. The soil carbon stocks depend strongly on the rate of input of carbon from the vegetation to the soil, and our analysis suggests that an improved simulation of photosynthesis would also lead to an improved simulation of soil carbon stocks. However, the stocks are also influenced by soil carbon burial (e.g. through cryoturbation) and the rate of heterotrophic respiration, which depends on the soil physical state. More detailed below-ground measurements are needed to fully evaluate biological and physical soil processes. Furthermore, even if these processes are well modelled, the soil carbon profiles cannot resemble peat layers as peat accumulation processes are not represented in the models. Thus, we identify three priority areas for model development: (1) dynamic vegetation including (a) climate and (b) nutrient limitation effects; (2) adding moss as a plant functional type; and an (3) improved vertical profile of soil carbon including peat processes.

The Role of Low-severity Fire and Thermal Alteration of Soil Organic Matter in Carbon Preservation and GHG Flux From Global Peatlands

NASA Astrophysics Data System (ADS)

Flanagan, N. E.; Wang, H.; Hodgkins, S. B.; Richardson, C. J.

2017-12-01

Many global peatlands are dominated by fire-adapted plant communities and are subject to frequent wildfires with return intervals ranging between 3 to 100 years. Wildfires in peatlands are typically low-severity events that occur in winter and spring when vegetation is desiccated and soil moisture content is high. As a result, most wildfires consume aboveground fuels in a matter of minutes without igniting the nearly saturated peat. In such fires, surface soil layers are subjected to flash heating with a rapid loss of soil moisture but little loss of soil organic matter (SOM). Such fires have the potential to alter the chemical structure of SOM, even in the absence of combustion, through Maillard's Reaction and similar chemical processes, and through structural changes that protect SOM from decomposition. This study examines the effects of low-intensity surface fires on the recalcitrance of SOM from fire-adapted communities located in subtropical, temperate and sub-boreal peatlands. In addition, soil from a non-fire-adapted Peruvian palm peatland was examined for response to thermal alteration. The timing and temperatures of low-intensity fires were measured in the field during prescribed burns and replicated in simulated fires. The effects of fire on the chemical structure of SOM were examined with FTIR, SEM and XPS. Burned and unburned peat replicates were incubated at three temperatures (5oC, 15oC, 25oC) in controlled chambers for more than six months. Burned replicates initially showed higher CO2, CH4 and NO2 emissions. Yet, within four weeks emissions from the burned replicates dropped below those of unburned replicates and remained significantly lower (10-50%) for the duration of the experiment. In addition, thermal alteration significantly reduced the temperature sensitivity (Q10) of thermally altered peat. After accounting for small initial losses of organic matter (<10 %) during the fire simulations, thermal alteration of SOM resulted in a net long-term reduction in carbon losses to microbial respiration. Such thermal alteration of SOM might be an underestimated factor influencing carbon accretion in frequently burned peatlands and could be globally relevant if climate change increases fire frequency in boreal peatlands.

The Influence of Hydrophobicity, Inorganic Amendments and Surfactants on Turfgrass Establishment, Growth and Quality in Constructed Root Zone Mixes

NASA Astrophysics Data System (ADS)

McMillan, Mica Franklin

Soil water repellency (SWR) negatively affects turfgrass growth and quality and impedes uniform distribution of water, particularly in sand-based rootzones. Surfactants and soil amendments such as calcined clay are two approaches to improving soil hydrological properties affected by SWR. However, studying SWR in the field is difficult due to the extreme spatial variability in the soil profile. An objective of this dissertation was to assess two methods to impart SWR on sand and examine SWR amelioration strategies using these procedures under a plant environment and deficit irrigation. To determine effectiveness of artificial hydrophobicity, two methods produced severely hydrophobic substrates: stearic acid sand (HSS) and sand:peat (90:10 sand:peat v/v)(HSP). Greenhouse studies compared the effects of substrates HSS, HSP, 100% sand (SAND), sand:peat (90:10 v/v) (SP), sand:calcined clay (90:10 v/v) (CC) and naturally water repellent sand (NWRS) on bermudagrass [Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt Davy] establishment and growth. Results indicate that HSS and HSP were not toxic to turfgrass but initially, hindered bermudagrass growth. At trials end, SWR had declined in both soils. A second greenhouse study assessed surfactant chemistry on substrates. After three dry downs, surfactants generally improved turfgrass quality in SAND and CC but had no significant effect in HSP and SP. Water drop penetration tests deemed CC and SAND wettable and HSP and SP nonwettable. Contact angle analysis found CC and SAND to be subcritically water repellent while HSP and SP were water repellent. Both HSP and HSS could be used to evaluate the influence of SWR on plant growth. However, both methods have disadvantages. CC remained wettable after several dry downs. In another greenhouse study, perennial ryegrass (Lolium perenne) seeds coated with 10% w/w alkyl-terminated block copolymer surfactant seed coating (SC) were evaluated as an amelioration strategy. Seed treated with surfactant yielded similar or greater percent coverage, shoot growth, root weight and increased volumetric water in the majority of substrates when compared to substrates sown with untreated seed. Coating seeds with surfactant may be used as a method to improve seed germination, establishment and enhance soil moisture, particularly under deficit irrigation.

Soil catenas on denudation plains in the forest-tundra and northern taiga zones of the Kola Peninsula

NASA Astrophysics Data System (ADS)

Urusevskaya, I. S.

2017-07-01

Morphogenetic features of soils of two catenas developed on sandy to loamy sandy moraine deposits in the forest-tundra and northern taiga zones on denudation plains of the Kola Peninsula are discussed. It is shown that these catenas are similar with respect to the major directions of soil formation, regularities of soil distribution by the elements of mesotopography, and the factors of the soil cover differentiation. The differences between the catenas are of quantitative character and are related to the intensities of manifestation of the particular processes and features. Both catenas are characterized by the pronounced differentiation of soils with respect to their moistening with hydromorphic peat bog soils in the subordinate positions and Al-Fe-humus podzols in the automorphic positions.

Effects of Sea Level Rise and Coastal Marsh Transgression on Soil Organic Matter in a Chesapeake Bay Salt Marsh

NASA Astrophysics Data System (ADS)

Van Allen, R.; Schreiner, K. M.; Guntenspergen, G. R.

2016-12-01

Salt marsh, mangrove swamp, and seagrass bed ecosystems comprise a global carbon stock known as "blue carbon." While vegetated coastal ecosystems have a small global areal extent, their total carbon burial rates are comparable to global marine carbon burial rates. Under global climate change-induced sea level rise, the role of these systems in the global carbon cycle could change significantly. This study aims to develop a more complete view of how coastal marsh transgression into terrestrial upland environments impacts soil organic matter characteristics. A US Geological Survey study site in Blackwater National Wildlife Refuge on the eastern coast of Chesapeake Bay, Maryland was chosen for this study. This marsh has undergone transgression into adjacent upland forest as local relative sea level has risen, making it an ideal location to study the source and stability of organic matter underlying the shifting marsh-forest boundary. Peat cores and vegetation samples were collected from the study site in May 2015 and June 2016. Care was taken to sample marsh soils underlying a range of elevations and vegetation types from the intertidal zone through the transition to upland forest. Radiocarbon and lead-210 dating give age estimates for basal peat layers within the cores. Analysis of stable carbon isotopes in bulk soils in this site suggests a broad shift towards C4-dominated marsh vegetation. Finally, cupric oxide oxidation products of soil organic matter provide information about the changing molecular organic geochemistry of the marsh soils as sea level rises and the marsh transgresses. This represents a novel molecular-level study of the changing organic geochemistry of marsh soils with sea level rise and resulting vegetation changes.

Derivation of greenhouse gas emission factors for peatlands managed for extraction in the Republic of Ireland and the United Kingdom

NASA Astrophysics Data System (ADS)

Wilson, D.; Dixon, S. D.; Artz, R. R. E.; Smith, T. E. L.; Evans, C. D.; Owen, H. J. F.; Archer, E.; Renou-Wilson, F.

2015-09-01

Drained peatlands are significant hotspots of carbon dioxide (CO2) emissions and may also be more vulnerable to fire with its associated gaseous emissions. Under the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol, greenhouse gas (GHG) emissions from peatlands managed for extraction are reported on an annual basis. However, the Tier 1 (default) emission factors (EFs) provided in the IPCC 2013 Wetlands Supplement for this land use category may not be representative in all cases and countries are encouraged to move to higher-tier reporting levels with reduced uncertainty levels based on country- or regional-specific data. In this study, we quantified (1) CO2-C emissions from nine peat extraction sites in the Republic of Ireland and the United Kingdom, which were initially disaggregated by land use type (industrial versus domestic peat extraction), and (2) a range of GHGs that are released to the atmosphere with the burning of peat. Drainage-related methane (CH4) and nitrous oxide (N2O) emissions as well as CO2-C emissions associated with the off-site decomposition of horticultural peat were not included here. Our results show that net CO2-C emissions were strongly controlled by soil temperature at the industrial sites (bare peat) and by soil temperature and leaf area index at the vegetated domestic sites. Our derived EFs of 1.70 (±0.47) and 1.64 (±0.44) t CO2-C ha-1 yr-1 for the industrial and domestic sites respectively are considerably lower than the Tier 1 EF (2.8 ± 1.7 t CO2-C ha-1 yr-1) provided in the Wetlands Supplement. We propose that the difference between our derived values and the Wetlands Supplement value is due to differences in peat quality and, consequently, decomposition rates. Emissions from burning of the peat (g kg-1 dry fuel burned) were estimated to be approximately 1346 CO2, 8.35 methane (CH4), 218 carbon monoxide (CO), 1.53 ethane (C2H6), 1.74 ethylene (C2H4), 0.60 methanol (CH3OH), 2.21 hydrogen cyanide (HCN) and 0.73 ammonia (NH3), and this emphasises the importance of understanding the full suite of trace gas emissions from biomass burning. Our results highlight the importance of generating reliable Tier 2 values for different regions and land use categories. Furthermore, given that the IPCC Tier 1 EF was only based on 20 sites (all from Canada and Fennoscandia), we suggest that data from another 9 sites significantly expand the global data set, as well as adding a new region.

Estimating the water budget for a peat filter treating septic tank effluent in the field

NASA Astrophysics Data System (ADS)

Van Geel, Paul J.; Parker, Wayne J.

2003-02-01

The use of peat as a filter medium for the treatment of a variety of liquid and gas waste streams has increased over the past decade. Peat has been used as an alternate treatment medium to treat septic tank effluent (STE) from domestic and small communal systems. Very little research has been completed to study the hydraulics and water budget of a peat filter operating in the field. This study evaluated the water budget of a peat filter operating at an elementary school near Ottawa, Canada. The peat filter was instrumented with tensiometers to measure the pore water pressures within the filter and a weather station to collect weather data required to estimate potential evapotranspiration. A one-dimensional unsaturated flow model, SoilCover, was calibrated using the pressure data and weather data collected in the field. The calibrated model was use to estimate the water budget for the filter operating with and without STE loading. The calibrated model predicted that the annual precipitation exceeded evapotranspiration for both scenarios. For the filter treating 50 mm/day of STE, there was a slight dilution due to the infiltration resulting in a net dilution factor of 0.97 (loading divided by the loading plus infiltration). The largest rainfall event of 49.9 mm resulted in a dilution factor of approximately 0.87, which corresponded to an approximate decrease in the hydraulic retention time (HRT) of between 12 and 33% depending on the calculation used to determine the HRT. When the filter does not receive STE, the precipitation exceeds evapotranspiration and hence the filter should not dry out when the filter is not in use.

The association of uranium with organic matter in Holocene peat: An experimental leaching study

USGS Publications Warehouse

Zielinski, R.A.; Meier, A.L.

1988-01-01

Uraniferous peat was sampled from surface layers of a Holocene U deposit in northeastern Washington State. Dried, sized, and homogenized peat that contained 5980 ??307 ppm U was subjected to a variety of leaching conditions to determine the nature and strength of U-organic bonding in recently accumulated organic matter. The results complement previous experimental studies of U uptake on peat and suggest some natural or anthropogenic disturbances that are favorable for remobilizing U. The fraction of U leached in 24 h experiments at 25??C ranged from 0 to 95%. The most effective leach solutions contained anions capable of forming stable dissolved complexes with uranyl (UO2+2) cation. These included H2SO4 (pH = 1.5) and concentrated (>0.01 M) solutions of sodium bicarbonate-carbonate (pH = 7.0-10.0), or sodium pyrophosphate (pH = 10). Effective leaching by carbonate and pyrophosphate in the absence of added oxidant, and the insignificant effect of added oxidant (as pressurized O2) strongly suggest that U is initially fixed on organic matter as an oxidized U(VI) species. Uranium is more strongly bound than some other polyvalent cations, based on its resistance to exchange in the presence of large excesses of dissolved Ca2+ and Cu2+. Measurements of the rate of U leaching indicate faster rates in acid solution compared to carbonate solution, and are consisten with simultaneous attack of sites with different affinities for U. Sulfuric acid appears a good choice for commercial extraction of U from mined peat. In situ disturbances such as overliming of peat soils, addition of fertilizers containing pyrophosphate, or incursions of natural carbonate-rich waters could produce significant remobilization of U, and possibly compromise the quality of local domestic water supplies. ?? 1988.

The composition and character of DOM from an upland peat catchment - sources, roles and fate

NASA Astrophysics Data System (ADS)

Worrall, F.; Moody, C.; Clay, G.; Boothroyd, I.; Burt, T. P.

2017-12-01

The fluvial fluxes of dissolved organic carbon (DOC) from peatlands form an important part of that ecosystem's carbon cycle, contributing approximately 35% of the overall peatland carbon budget. The source, role and fate of this component of the carbon cycle was explored for a peat covered catchment in the north east of England with dissolved organic matter (DOM) being sampled from both a first-order peat-hosted stream and soil water at two depths within the peat profile. All DOM samples were analysed within the context of analysing the particulate organic matter (POM) from the catchment; the peat profile; and biomass. All samples were analysed using: elemental analysis (C, H, N, O, P and S); bomb calorimetry; thermogravimetric analysis (TGA); 13C solid state NMR; and S isotopes. Furthermore, the degradation of fresh DOC was examined over periods of 70 hours every month for 23 months. The analysis has shown that: DOM is highly oxidised compared to all other organic in the ecosystem and DOM did not exist until [C]/[O] < 1.44. The DOM was dominantly the product of lignin breakdown and not the processing of proteins or carbohydrates, i.e. it was not an intermediate of oxidation to CO2. DOM could only be sourced from high in the peat profile at most above 41 cm depth. Thermodynamic inhibition shows that only DOM from the surface layers could be reactive in the catotelmic layers of the peat. There was a significant role for the composition of the DOM in controlling degradation with degradation rates significantly increasing with the proportion of aldehyde and carboxylic acid functional groups but decreasing with the proportion of N-alkyl functional groups. The study meant that is was possible to consider the behaviour of DOM in terms of its thermodynamic properties (DH, DS & DG) for both formation and reaction.

Northern Peatland Shifts Under Changing Climate and Their Impact on Permafrost

NASA Astrophysics Data System (ADS)

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

2014-12-01

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

Recovery of microbial diversity and activity during bioremediation following chemical oxidation of diesel contaminated soils.

PubMed

Sutton, Nora B; Langenhoff, Alette A M; Lasso, Daniel Hidalgo; van der Zaan, Bas; van Gaans, Pauline; Maphosa, Farai; Smidt, Hauke; Grotenhuis, Tim; Rijnaarts, Huub H M

2014-03-01

To improve the coupling of in situ chemical oxidation and in situ bioremediation, a systematic analysis was performed of the effect of chemical oxidation with Fenton's reagent, modified Fenton's reagent, permanganate, or persulfate, on microbial diversity and activity during 8 weeks of incubation in two diesel-contaminated soils (peat and fill). Chemical oxidant and soil type affected the microbial community diversity and biodegradation activity; however, this was only observed following treatment with Fenton's reagent and modified Fenton's reagent, and in the biotic control without oxidation. Differences in the highest overall removal efficiencies of 69 % for peat (biotic control) and 59 % for fill (Fenton's reagent) were partially explained by changes in contaminant soil properties upon oxidation. Molecular analysis of 16S rRNA and alkane monooxygenase (alkB) gene abundances indicated that oxidation with Fenton's reagent and modified Fenton's reagent negatively affected microbial abundance. However, regeneration occurred, and final relative alkB abundances were 1-2 orders of magnitude higher in chemically treated microcosms than in the biotic control. 16S rRNA gene fragment fingerprinting with DGGE and prominent band sequencing illuminated microbial community composition and diversity differences between treatments and identified a variety of phylotypes within Alpha-, Beta-, and Gammaproteobacteria. Understanding microbial community dynamics during coupled chemical oxidation and bioremediation is integral to improved biphasic field application.

Degradation of isoproturon and bentazone in peat- and compost-based biomixtures.

PubMed

Coppola, Laura; Pilar Castillo, Maria Del; Vischetti, Costantino

2011-01-01

The composition and properties of a biomixture used in a biobed are decisive for pesticide sorption and degradation. This study was performed to investigate the capability of compost-based substrates in mixtures with citrus peel and vine branch straw and peat-based substrates in mixtures with soil and vine branch straw at different levels in order to degrade isoproturon and bentazone. Dissipation and mineralisation rates of both pesticides were determined, and metabolic activity was followed as respiration. Compost-based substrates showed faster pesticide dissipation in the presence of lignocellulosic materials, as in garden compost and vine branch straw. The increasing content of vine branch straw in peat-based substrates does not seem to affect dissipation of the parent compounds. Low mineralisation rate was observed in all treatments. Higher pesticide degradation was observed in the lignocellulosic substrates, probably because of the development of lignin-degrading microorganisms which have shown to be robust and are able to degrade recalcitrant pesticides. Copyright © 2010 Society of Chemical Industry. Copyright © 2010 Society of Chemical Industry.

Soil-atmosphere trace gas exchange from tropical oil palm plantations on peat

NASA Astrophysics Data System (ADS)

Arn Teh, Yit; Manning, Frances; Zin Zawawi, Norliyana; Hill, Timothy; Chocholek, Melanie; Khoon Kho, Lip

2015-04-01

Oil palm is the largest agricultural crop in the tropics, accounting for 13 % of all tropical land cover. Due to its large areal extent, oil palm cultivation may have important implications not only for terrestrial stores of C and N, but may also impact regional and global exchanges of material and energy, including fluxes of trace gases and water vapor. In particular, recent expansion of oil palm into tropical peatlands has raised concerns over enhanced soil C emissions from degradation of peat, and elevated N-gas fluxes linked to N fertilizer application. Here we report our preliminary findings on soil carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes from a long-term, multi-scale project investigating the C, N and greenhouse gas (GHG) dynamics of oil palm ecosystems established on peat soils in Sarawak, Malaysian Borneo. Flux chamber measurements indicate that soil CO2, CH4 and N2O fluxes averaged 20.0 ± 16.0 Mg CO2-C ha-1 yr-1, 37.4 ± 29.9 kg CH4-C ha-1 yr-1 and 4.7 ± 4.2 g N2O-N ha-1 yr-1, respectively. Soil CO2 fluxes were on par with other drained tropical peatlands; whereas CH4 fluxes exceeded observations from similar study sites elsewhere. Nitrous oxide fluxes were in a similar range to fluxes from other drained tropical peatlands, but lower than emissions from mineral-soil plantations by up to three orders of magnitude. Fluxes of soil CO2 and N2O were spatially stratified, and contingent upon the distribution of plants, deposited harvest residues, and soil moisture. Soil CO2 fluxes were most heavily influenced by the distribution of palms and their roots. On average, autotrophic (root) respiration accounted for approximately 78 % of total soil CO2 flux, and total soil respiration declined steeply away from palms; e.g. soil CO2 fluxes in the immediate 1 m radius around palms were up to 6 times greater than fluxes in inter-palm spaces due to higher densities of roots. Placement of harvest residues played an important - but secondary - role in modulating soil CO2 fluxes; soil respiration rates doubled in areas where harvest residues were deposited, reflecting an enhanced input of labile organic matter for decomposition. In contrast, N2O fluxes were best-predicted by the distribution of harvest residues, and were only weakly related to plant distributions or soil moisture. For example, N2O fluxes from harvest residue piles were up to twice of the overall plot-average. In contrast, N2O fluxes showed no clear pattern around palms or in inter-palm spaces; this finding is surprising because N fertilizers are applied within the 1 m radius around palms, and we expected to observe enhanced N2O fluxes in areas of greater fertilizer input. This suggests that palms may be a strong competitor for N in these ecosystems, and that fertilizer application may more closely match overall plant demand than in mineral-soil plantations. Overall, the spatial patterning of soil CO2 and N2O fluxes implies that soil biogeochemical processes are predictably distributed in space, potentially making it easier to model and constrain fluxes of these soil-derived GHGs.

Recycling of phenolic compounds in Borneo's tropical peat swamp forests.

PubMed

Yule, Catherine M; Lim, Yau Yan; Lim, Tse Yuen

2018-02-07

Tropical peat swamp forests (TPSF) are globally significant carbon stores, sequestering carbon mainly as phenolic polymers and phenolic compounds (particularly as lignin and its derivatives) in peat layers, in plants, and in the acidic blackwaters. Previous studies show that TPSF plants have particularly high levels of phenolic compounds which inhibit the decomposition of organic matter and thus promote peat accumulation. The studies of phenolic compounds are thus crucial to further understand how TPSF function with respect to carbon sequestration. Here we present a study of cycling of phenolic compounds in five forests in Borneo differing in flooding and acidity, leaching of phenolic compounds from senescent Macaranga pruinosa leaves, and absorption of phenolics by M. pruinosa seedlings. The results of the study show that total phenolic content (TPC) in soil and leaves of three species of Macaranga were highest in TPSF followed by freshwater swamp forest and flooded limestone forest, then dry land sites. Highest TPC values were associated with acidity (in TPSF) and waterlogging (in flooded forests). Moreover, phenolic compounds are rapidly leached from fallen senescent leaves, and could be reabsorbed by tree roots and converted into more complex phenolics within the leaves. Extreme conditions-waterlogging and acidity-may facilitate uptake and synthesis of protective phenolic compounds which are essential for impeded decomposition of organic matter in TPSF. Conversely, the ongoing drainage and degradation of TPSF, particularly for conversion to oil palm plantations, reverses the conditions necessary for peat accretion and carbon sequestration.

Native nematodes as new bio-insecticides for cranberries

USDA-ARS?s Scientific Manuscript database

In the summer of 2015, an effort was made in central Wisconsin to find an entomopathogenic nematode capable controlling Wisconsin’s cranberry pests. Using a standard baiting method, a nematode of the Oscheius genus was collected from the mossy, sandy, peat-filled soils of a wild cranberry marsh. Thi...

Carbon dioxide emissions from peat soils under potato cultivation in Uganda

NASA Astrophysics Data System (ADS)

Farmer, Jenny; Langan, Charlie; Smith, Jo

2017-04-01

Organic wetland soils in south western Uganda are found in valley bottom wetlands, surrounded by steep, mineral soil hill slopes. Land use change in these papyrus dominated wetlands has taken place over the past forty years, seeing wetland areas cleared of papyrus, rudimentary drainage channel systems dug, and soil cultivated and planted with crops, predominantly potatoes. There has been little research into the cultivation of organic wetlands soils in Uganda, or the impacts on soil carbon dynamics and associated carbon dioxide (CO2) emissions. This study used two rounds of farmer interviews to capture the land management practices on these soils and how they vary over the period of a year. Three potato fields were also randomly selected and sampled for CO2 emissions at four points in time during the year; 1) just after the potato beds had been dug, 2) during the potato growing period, 3) after the potato harvest, and 4) at the end of the fallow season. Carbon dioxide emissions, soil and air temperatures, water table depth, vegetation cover and land use were all recorded in situ in each field on each sampling occasion, from both the raised potato beds and the trenches in between them. There appeared to be a delay in the disturbance effect of digging the peat, with heterotrophic CO2 emissions from the raised beds not immediately increasing after being exposed to the air. Excluding these results, there was a significant linear relationship between mean emissions and water table depth from the raised beds and trenches in each field over time (p<0.001, r2=0.85), as well as between emissions and soil moisture content (p<0.001, r2=0.85). Temporal variability was observed, with significant differences in the means of emissions measured at the different sampling times (p<0.001, one-way ANOVA); this was the case in both raised beds and trenches in all fields studied, except for the trenches in one field which showed no significant difference between sampling times (p=0.55). Mean emissions from the raised beds were highest during the potato growing season (1.74 ± 0.07 g m-2 hr-1 (± shows standard error)) and lowest at the time when the beds had been freshly dug (0.67 ± 0.17 g m-2 hr-1). Mean emissions from the trenches were highest at the end of the fallow period (0.37 ± 0.02 g m-2 hr-1) and lowest at the time when the beds had been freshly dug (0.20 ± 0.05 g m-2 hr-1). As the first of its kind on Uganda's peat soils, this study has provided some insight into the use of these soils and impacts on CO2 emissions which can be used to inform Uganda's national emissions scenarios, whilst highlighting some of the fundamental data gaps which need to be addressed with future studies.

The influence of the sorptive properties of organic soils on the migration rate of 137Cs.

PubMed

Chibowski, S; Zygmunt, J

2002-01-01

Using a compartment model, the migration rates of 137Cs were calculated for two types of organic soils: a low peat-muck soil and a black earth. The migration rates of 137Cs in the tested soils turned out to be significantly higher than in mineral types examined earlier and ranged from 0.6 to 12.3 cm/year. The partition coefficients (Kd) were also determined for samples with varying organic matter content (OM) that were taken from different layers of the studied soils. The experimental results indicate that there is a clear relationship between Kd values and OM. The investigation was widened by microcalorimetric measurements which confirmed that the adsorption of 137Cs on the organic soils is low.

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

PubMed

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

2006-08-01

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

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

USGS Publications Warehouse

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

2014-01-01

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

The effects of fire on greenhouse gas fluxes from mosses and lichen patches in the Yukon Kuskokwim Delta, AK.

NASA Astrophysics Data System (ADS)

Navarro-Perez, E.; Natali, S.; Schade, J. D.; Holmes, R. M.; Mann, P. J.

2017-12-01

Climate change has altered patterns of temperature, emissions of greenhouse gases and increased fire frequencies, especially in the Artic. Until recently, the Arctic has been a carbon (C) sink, but have begun releasing C in recent years, likely in response to warming temperatures, permafrost thaw and resulting changes in microbial processes. In addition, increases in fire frequency and intensity are changing vegetation patterns, particularly the relative importance of mosses and lichens. These changes alter soil temperatures, nutrient availability, and moisture, consequently affecting microbial processes and the release of greenhouse gases (GHG) such as N2O, CO2 and CH4. The objective of this research was to understand how recent fires in the Yukon-Kuskokwim River Delta in southwest Alaska are affecting the emission of GHGs from peat plateau soils. We hypothesized that the presence of mosses and lichen would change soil moisture and temperature, leading to changes in GHG production after fire. We also hypothesized that fire would increase soil nutrient availability, which would increase microbial process rates and GHG emissions. To test these hypotheses, we measured N2O, CH4 and CO2 fluxes from moss and lichen patches in three burned and unburned areas and collected soil cores for analyses of gravimetric soil moisture, carbon and nitrogen concentrations, and N mineralization rates. Soil temperatures were measured in the field with a thermocouple. Results demonstrated low but measurable CH4 emissions from all patches, suggesting peat plateaus in the YK Delta may be CH4 sources. In addition, CO2 emissions were higher in soils under lichen patches in burned areas than unburned controls. Finally, results suggest that burned areas have higher concentrations of extractable NH4 and NO3, and that increased N may be increasing soil respiration.

Partitioning of soil CO2 efflux in un-manipulated and experimentally flooded plots of a temperate fen

NASA Astrophysics Data System (ADS)

Wunderlich, S.; Borken, W.

2012-05-01

Peatlands store large amounts of organic carbon, but the carbon stock is sensitive to changes in precipitation or water table manipulations. Restoration of drained peatlands by drain blocking and flooding is a common measure to conserve and augment the carbon stock of peatland soils. Here, we report to what extent flooding affected the contribution of heterotrophic and rhizosphere respiration to soil CO2 efflux in a grass-dominated mountain fen, Germany. Soil CO2 efflux was measured in three un-manipulated control plots and three flooded plots in two consecutive years. Flooding was achieved by permanent irrigation during the growing seasons. Radiocarbon signatures of CO2 from different sources including soil CO2 efflux, incubated peat cores and live grass roots were repeatedly analyzed for partitioning of soil CO2 efflux. Additionally, heterotrophic respiration and its radiocarbon signature were determined by eliminating rhizosphere respiration in trenched subplots (only control). In the control plots, rhizosphere respiration determined by 14C signatures contributed between 47 and 61% during the growing season, but was small (4%) immediately before budding. Trenching revealed a smaller rhizosphere contribution of 33% (2009) and 22% (2010) during growing seasons. Flooding reduced annual soil CO2 efflux of the fen by 42% in 2009 and by 30% in 2010. The reduction was smaller in 2010 mainly through naturally elevated water level in the control plots. A 1-week interruption of irrigation caused a strong short-lived increase in soil CO2 efflux, demonstrating the sensitivity of the fen to water table drawdown near the peat surface. The reduction in soil CO2 efflux in the flooded plots diminished the relative proportion of rhizosphere respiration from 56 to 46%, suggesting that rhizosphere respiration was slightly more sensitive to flooding than heterotrophic respiration. We conclude that the moderate decrease in rhizosphere respiration following flooding arises from a gradual change in vegetation in this fen ecosystem.

Partitioning of soil CO2 efflux in un-manipulated and experimentally flooded plots of a temperate fen

NASA Astrophysics Data System (ADS)

Wunderlich, S.; Borken, W.

2012-08-01

Peatlands store large amounts of organic carbon, but the carbon stock is sensitive to changes in precipitation or water table manipulations. Restoration of drained peatlands by drain blocking and flooding is a common measure to conserve and augment the carbon stock of peatland soils. Here, we report to what extent flooding affected the contribution of heterotrophic and rhizosphere respiration to soil CO2 efflux in a grass-dominated mountain fen in Germany. Soil CO2 efflux was measured in three un-manipulated control plots and three flooded plots in two consecutive years. Flooding was achieved by permanent irrigation during the growing seasons. Radiocarbon signatures of CO2 from different sources including soil CO2 efflux, incubated peat cores and live grass roots were repeatedly analyzed for partitioning of soil CO2 efflux. Additionally, heterotrophic respiration and its radiocarbon signature were determined by eliminating rhizosphere respiration in trenched subplots (only control). In the control plots, rhizosphere respiration determined by 14C signatures contributed between 47 and 61% during the growing season, but was small (4 ± 8%) immediately before budding. Trenching revealed a smaller rhizosphere contribution of 33 ± 8% (2009) and 22 ± 9% (2010) during growing seasons. Flooding reduced annual soil CO2 efflux of the fen by 42% in 2009 and by 30% in 2010. The reduction was smaller in 2010 mainly through naturally elevated water level in the control plots. A one-week interruption of irrigation caused a strong short-lived increase in soil CO2 efflux, demonstrating the sensitivity of the fen to water table drawdown near the peat surface. The reduction in soil CO2 efflux in the flooded plots diminished the relative proportion of rhizosphere respiration from 56 to 46%, suggesting that rhizosphere respiration was slightly more sensitive to flooding than heterotrophic respiration.

Cone Penetration Testing, a new approach to quantify coastal-deltaic land subsidence by peat consolidation

NASA Astrophysics Data System (ADS)

Koster, Kay; Erkens, Gilles; Zwanenburg, Cor

2016-04-01

It is undisputed that land subsidence threatens coastal-deltaic lowlands all over the world. Any loss of elevation (on top of sea level rise) increases flood risk in these lowlands, and differential subsidence may cause damage to infrastructure and constructions. Many of these settings embed substantial amounts of peat, which is, due to its mechanically weak organic composition, one of the main drivers of subsidence. Peat is very susceptible to volume reduction by loading and drainage induced consolidation, which dissipates pore water, resulting in a tighter packing of the organic components. Often, the current state of consolidation of peat embedded within coastal-deltaic subsidence hotspots (e.g. Venice lagoon, Mississippi delta, San Joaquin delta, Kalimantan peatlands), is somewhere between its initial (natural) and maximum compressed stage. Quantifying the current state regarding peat volume loss, is of utmost importance to predict potential (near) future subsidence when draining or loading an area. The processes of subsidence often afflict large areas (>103 km2), thus demanding large datasets to assess the current state of the subsurface. In contrast to data describing the vertical motions of the actual surface (geodesy, satellite imagery), subsurface information applicable for subsidence analysis are often lacking in subsiding deltas. This calls for new initiatives to bridge that gap. Here we introduce Cone Penetration Testing (CPT) to quantify the amount of volume loss peat layers embedded within the Holland coastal plain (the Netherlands) experienced. CPT measures soil mechanical strength, and hundreds of thousands of CPTs are conducted each year on all continents. We analyzed 28 coupled CPT-borehole observations, and found strong empirical relations between volume loss and increased peat mechanical strength. The peat lost between ~20 - 95% of its initial thickness by dissipation of excess pore water. An increase in 0.1 - 0.4 MPa of peat strength is accountable for 20 - 75 % of the volume loss, and 0.4 - 0.7 MPa for 75 - 95 % volume loss. This indicates that large amounts of volume by water dissipation has to be lost, before peat experiences a serious increase in strength, which subsequently continuous to increase with only small amount of volume loss. To demonstrate the robustness of our approach to the international field of land subsidence, we applied the obtained empirical relations to previously published CPT logs deriving from the peat-rich San Joaquin-Sacramento delta and the Kalimantan peatlands, and found volume losses that correspond with previously published results. Furthermore, we used the obtained results to predict maximum surface lowering for these areas by consolidation. In conclusion, these promising results and its worldwide popularity yielding large datasets, open the door for CPT as a generic method to contribute to quantifying the imminent threat of coastal-deltaic land subsidence.

Modelling carbon cycle in boreal wetlands with the Earth System Model ECHAM6/MPIOM

NASA Astrophysics Data System (ADS)

Getzieh, Robert J.; Brovkin, Victor; Kleinen, Thomas; Raivonen, Maarit; Sevanto, Sanna

2010-05-01

Wetlands of the northern high latitudes provide excellent conditions for peat accumulation and methanogenesis. High moisture and low O2 content in the soils lead to effective preservation of soil organic matter and methane emissions. Boreal Wetlands contain about 450 PgC and currently constitute a significant natural source of methane (CH4) even though they cover only 3% of the global land surface. While storing carbon and removing CO2 from the atmosphere, boreal wetlands have contributed to global cooling on millennial timescales. Undisturbed boreal wetlands are likely to continue functioning as a net carbon sink. On the other hand these carbon pools might be destabilised in future since they are sensitive to climate change. Given that processes of peat accumulation and decay are closely dependent on hydrology and temperature, this balance may be altered significantly in the future. As a result, northern wetlands could have a large impact on carbon cycle-climate feedback mechanisms and therefore play an important role in global carbon cycle dynamics. However global biogeochemistry models used for simulations of CO2 dynamics in past and future climates usually neglect carbon cycle in wetlands. We investigate the potential for positive or negative feedbacks to the climate system through fluxes of greenhouse gases (CO2 and CH4) with the general circulation model ECHAM6/MPIOM. A generic model of peat accumulation and decay has been developed and implemented into the land surface module JSBACH. We consider anaerobic biogeochemical processes which lead to formation of thick organic soils. Furthermore we consider specific wetland plant functional types (PFTs) in our model such as vascular plants (sedges) which impact methane transport and oxidation processes and non vascular plants (sphagnum mosses) which are promoting peat growth. As prototypes we use the modelling approaches by Frolking et al. (2001) as well as Walter & Heimann (2001) for the peat dynamics, and the wetland model by Wania (2008) for vegetation cover and methane emissions. An initial distribution of wetlands follows the GLWD-3 map by Lehner and Döll (2004). A dynamical wetlands hydrology scheme (T. Stacke) and a methane transport and emission model (M. Raivonen) are at the moment also under development at the MPI for Meteorology respectively in close cooperation with the University of Helsinki. First results of our modelling approach will be presented. REFERENCES S. Frolking et al., Ecosystems 4, 479-498 (2001). B. Lehner et al., Journal of Hydrology 296, 1-22 (2004). B. P. Walter et al., J. Geophys. Res. 106, D24, 34189-34206 and 34207-34219 (2001). R. Wania et al., Global Biogeochem. Cycles 23, GB3014 and GB3015 (2009).

The Impact of Climate Change on Microbial Communities and Carbon Cycling in High Arctic Permafrost Soil from Spitsbergen, Northern Norway

NASA Astrophysics Data System (ADS)

de Leon, K. C.; Schwery, D.; Yoshikawa, K.; Christiansen, H. H.; Pearce, D.

2014-12-01

Permafrost-affected soils are among the most fragile ecosystems in which current microbial controls on organic matter decomposition are changing as a result of climate change. Warmer conditions in the high Arctic will lead to a deepening of the seasonal active layer of permafrost, provoking changes in microbial processes and possibly resulting in exacerbated carbon degradation under increasing anoxic conditions. The viable and non-viable fractions of the microbial community in a permafrost soil from Adventdalen, Spitsbergen, Norway were subjected to a comprehensive investigation using culture-dependent and culture-independent methods. Molecular analyses using FISH (with CTC-DAPI) and amplified rDNA restriction analysis (ARDRA) on a 257cm deep core, revealed the presence of all major microbial soil groups, with the active layer having more viable cells, and a higher microbial community diversity. Carbon dioxide (CO2) and methane (CH4) flux measurements were performed to show the amount of C stored in the sample. We demonstrated that the microbial community composition from the soil in the center of the core was most likely influenced by small scale variations in environmental conditions. Community structure showed distinct shift of presence of bacterial groups along the vertical temperature gradient profile and microbial counts and diversity was found to be highest in the surface layers, decreasing with depth. It was observed that soil properties driving microbial diversity and functional potential varied across the permafrost table. Data on the variability of CO2 and CH4 distribution described in peat structure heterogeneity are important for modeling emissions on a larger scale. Furthermore, linking microbial biomass to gas distribution may elucidate the cause of peak CO2 and CH4 and their changes in relation to environmental change and peat composition.

Hydrology and Geostatistics of a Vermont, USA Kettlehole Peatland

NASA Astrophysics Data System (ADS)

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

2005-01-01

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

Impact of fire on macropore flow and the hydraulic conductivity of near-surface blanket peat

NASA Astrophysics Data System (ADS)

Holden, Joseph; Wearing, Catherine; Palmer, Sheila; Jackson, Benjamin; Johnston, Kerrylyn; Brown, Lee

2013-04-01

Peatlands can be subject to wildfire or deliberate burning in many locations. Wildfires are known to impact soil properties and runoff production in most soil types but relatively little work has been conducted on peatlands. Furthermore in large parts of the UK uplands prescribed vegetation burning on peat has taken place at regular intervals (e.g. every 8-25 years) on patches of around 300-900 sq. metres over the past century to support increased grouse populations for sport shooting. However, there have been few studies on how these prescribed fires influence near-surface hydrology. It is known that macropores transport a large proportion of flow in near-surface peat layers and we investigated their role in flow transport for fire sites using tension infiltrometers. Measurements were performed, at replicated hillslope positions to control for slope position effects, on unburnt peat (U) and where prescribed burning had taken place two years (P2), four years (P4) and >15 years (P15+) prior to sampling. For the prescribed burning plots, vegetation burning had also occurred at around a 15-20 year interval for most of the past century. We also sampled a nearby wildfire site (W) with the same sampling design where wildfire had occurred four months prior to sampling. Both the contribution of macropore flow to overall infiltration, and the saturated hydraulic conductivity, were significantly lower in the recently burnt sites (W, P2, P4), compared to P15+ and U. There was no significant difference in macropore flow contributions, effective macroporosity and saturated hydraulic conductivity between P15+ and U. The results suggest fire influences the near-surface hydrological functioning of peatlands but that 'recovery' for some hydrological processes to prescribed vegetation burning may be possible within two decades if there are no further fires.

The production of black carbon during managed burning of UK peatlands: could managed burning of peatlands lead to enhanced carbon storage?

NASA Astrophysics Data System (ADS)

Clay, G.; Worrall, F.

2008-12-01

Peatlands are the UK's largest single terrestrial carbon store with carbon stored in UK peatlands than in forests of Britain and France combined. Unlike most northern peatlands in the peat soils of the UK are heavily managed for recreation and agriculture and due to their proximity to major centres of population are under more anthropogenic pressure than most peatlands. A typical management strategy on UK upland peats is the use of managed fire to restrict vegetation. Fires are used upon a 10-25 year rotation and are described as "cool" as they are designed to remove the crown of the vegetation without scorching the litter layer or the underlying soil. In this case the fire destroys primary productivity and limits litter production but produces char. Char is a low volume, highly refractory, high carbon content product while litter is a high volume, decomposable, lower carbon content product. Therefore, the question is if there are fire conditions under which the production of char causes more carbon to be stored in the peat than would have been stored if no fire management had been employed. This study combines field studies of recent managed burns and wildfires along with detailed vegetation studies from a long term monitoring site in order to assess litter, biomass and black carbon production. In the laboratory experimental burns were undertaken in order to assess the amount and controls upon char production and the carbon content of that char. Results of field and laboratory observations are used to model carbon accumulation under a series of fire management scenarios and the modelling shows that cools burns at long rotations could lead to higher carbon storage than if no fire had occurred, further in several cases more carbon accumulation occurred even if less depth of peat was generated.

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

Hornibrook, E.R.C.; Longstaffe, F.J.; Fyfe, W.S.

The identity and distribution of substrates that support CH{sub 4} production in wetlands is poorly known at present. Organic compounds are the primary methanogenic precursor at all depths within anoxic wetland soils; however, the distribution of microbial processes by which these compounds are ultimately converted to CH{sub 4} is uncertain. Based on stable isotope measurements of CH{sub 4} and {Sigma}CO{sub 2} extracted from soil porewaters in two temperate zone wetlands, we present evidence that a systematic spatial distribution of microbial methanogenic pathways can exist in certain anoxic, organic-rich soils. CH{sub 4} production by the acetate fermentation pathway is favored inmore » the shallow subsurface. while methanogenesis from the reduction of CO{sub 2} with H{sub 2} becomes more predominant in older, less reactive peat at depth. This distribution can account for many of the reported CH{sub 4} emission characteristics of wetlands, in particular, their sensitivity to changes in primary productivity, temperature, and hydrology. These factors play an important role in controlling the short-term supply of labile substrates to fermentive methanogens in the shallow subsurface where the most intense CH{sub 4} production occurs. Predominance of the CO{sub 2}-reduction pathway at depth may help to explain reports of CH{sub 4} with a semifossil age in lower peat layers. 60 refs., 7 figs., 1 tab.« less

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

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

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

1982-11-01

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

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

NASA Astrophysics Data System (ADS)

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

2016-12-01

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

Detection of high concentrations of organic acids in fish emulsion and their role in pathogen or disease suppression.

PubMed

Abbasi, Pervaiz A; Lazarovits, George; Jabaji-Hare, Suha

2009-03-01

Fish emulsion (FE) added to a sandy-loam soil at 1 and 2% rates reduced the viability of Verticillium dahliae microsclerotia by 39 and 74% in 1 day, 87 and 98% in 3 days, and 95 and 99% in 6 days, respectively. The immediate kill of microsclerotia indicated that FE contains toxic substances. We found in FE high concentrations (400 mmol/liter) of organic acids, including some known toxicants. Glycolic, acetic, formic, n-butyric, and propionic acids were the major organic acids detected in FE at the proportions of 52.5, 26.9, 7.9, 7.2, and 4.7%, respectively. In solution assays, the viability of V. dahliae microsclerotia treated for 24 h in 1, 2, 5, and 10% FE (pH 3.6 to 3.0) or a mixture of organic acids (pH 4.1 to 3.9) equivalent to the proportions in FE was reduced by 74, 94, 97, and 99% or 81, 91, 98, and 99%, respectively. The viability of microsclerotia was increased when the treatment solutions were buffered to pH 6.0. The organic acids mixtures and formic (0.025%) and acetic (0.1%) acids were toxic to Pythium ultimum. A mixture of organic acids (1, 2, and 4%) provided immediate protection of cucumber seedlings from damping-off in P. ultimum-infested muck and sandy-loam soils but not in peat-based mix. FE (1 and 2%) provided immediate protection of cucumber seedlings from damping-off in an infested muck soil, and disease protection was consistent when planting was delayed for 7, 14, and 28 days after adding FE. FE (1, 2, and 4%) did not provide immediate protection of cucumber seedlings from damping-off in a P. ultimum-infested peat-based mix; however, disease suppression was evident when planting was delayed for 7, 14, and 21 days after adding FE. Real-time polymerase chain reaction analyses of the peat-based mix indicated that the P. ultimum populations in the FE-amended mix declined over time. This study suggests that these organic acids in FE played a major role in pathogen or disease suppression, depending on the soil and substrate.

An immunological approach to quantifying the saprotrophic growth dynamics of Trichoderma species during antagonistic interactions with Rhizoctonia solani in a soil-less mix.

PubMed

Thornton, Christopher R

2004-04-01

Studies of the saprotrophic growth dynamics of Trichoderma species and their fungal hosts during antagonistic interactions are severely hampered by the absence of methods that allow the unambiguous identification and quantification of individual genera in complex environments such as soil or compost containing mixed populations of fungi. Furthermore, methods are required that allow discrimination between active hyphal growth and other components of fungal biomass such as quiescent spores that are produced in large numbers by Trichoderma species. This study details the use of monoclonal antibodies to quantify the saprotrophic growth dynamics of the soil-borne plant pathogen Rhizoctonia solani and biological control strains of Trichoderma asperellum and Trichoderma harzianum during antagonistic interactions in peat-based microcosms. Quantification was based on the immunological detection of constitutive, extracellular antigens that are secreted from the growing tip of Rhizoctonia and Trichoderma mycelium and, in the case of Trichoderma harzianum, from quiescent phialoconidia also. The Trichoderma-specific monoclonal antibody (MF2) binds to a protein epitope of the enzyme glucoamylase, which was shown by immunofluorescence and immunogold electron gold microscopy studies of Trichoderma virens in vitro to be produced at the origin of germ tube emergence in phialoconidia and from the growing tip of germ tubes. In addition, a non-destructive immunoblotting technique showed that the enzyme was secreted during active growth of Trichoderma asperellum mycelium in peat. The Rhizoctonia solani-specific monoclonal antibody (EH2) similarly binds to a protein epitope of a glycoprotein that is secreted during active mycelial growth. Extracts derived from lyophilized mycelium were used as a quantifiable and repeatable source of antigens for construction of calibration curves. These curves were used to convert the absorbance values obtained in ELISA tests of peat extracts to biomass equivalents, which allowed comparisons of the saprotrophic growth dynamics of the pathogen and antagonists to be made in single or mixed species microcosms. Trichoderma species were able to compete successfully with R. solani for nutrients and to prevent saprotrophic growth of the pathogen. Specificity of the Trichoderma quantitative assay was tested in non-sterile soil-based microcosms artificially inoculated with T. asperellum. The assay was highly specific and only detected T. asperellum population dynamics. No cross-reactivity was found with extracts from soil samples containing contaminant fungi.

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

McNicol, Gavin

Wetlands cover only a small fraction of the Earth’s land surface, but have a disproportionately large influence on global climate. Low oxygen conditions in wetland soils slows down decomposition, leading to net carbon dioxide sequestration over long timescales, while also favoring the production of redox sensitive gases such as nitrous oxide and methane. Freshwater marshes in particular sustain large exchanges of greenhouse gases under temperate or tropical climates and favorable nutrient regimes, yet have rarely been studied, leading to poor constraints on the magnitude of marsh gas sources, and the biogeochemical drivers of flux variability. The Sacramento-San Joaquin Delta inmore » California was once a great expanse of tidal and freshwater marshes but underwent drainage for agriculture during the last two centuries. The resulting landscape is unsustainable with extreme rates of land subsidence and oxidation of peat soils lowering the surface elevation of much of the Delta below sea level. Wetland restoration has been proposed as a means to slow further subsidence and rebuild peat however the balance of greenhouse gas exchange in these novel ecosystems is still poorly described. In this dissertation I first explore oxygen availability as a control on the composition and magnitude of greenhouse gas emissions from drained wetland soils. In two separate experiments I quantify both the temporal dynamics of greenhouse gas emission and the kinetic sensitivity of gas production to a wide range of oxygen concentrations. This work demonstrated the very high sensitivity of carbon dioxide, methane, and nitrous oxide production to oxygen availability, in carbon rich wetland soils. I also found the temporal dynamics of gas production to follow a sequence predicted by thermodynamics and observed spatially in other soil or sediment systems. In the latter part of my dissertation I conduct two field studies to quantify greenhouse gas exchange and understand the carbon sources for decomposition in a 1 km2 restored wetland in the Sacramento Delta. By coupling flux measurements at multiple-scales with remote sensing imagery I showed that large methane emissions produce an overall climate warming effect from the wetland for the next several centuries, despite relatively high productivity. I also used radiocarbon analyses of wetland sediment carbon dioxide and methane to show that both bulk peat and recently fixed carbon contribute to decomposition in the wetland, and that their relative importance is regulated by proximity to, and the phenological cycles of, emergent vegetation.« less

Forestry Best Management Practices for Wetlands in Minnesota

Treesearch

Michael J. Phillips

1997-01-01

Wetlands are a common landscape feature in Minnesota in spite of significant losses of wetlands to agriculture and development. Prior to European settlement, Minnesota contained 7.5 million ha of wetlands, including both wet, mineral and peat soils. These wetlands covered approximately 35 percent of the state. The current extent of wetlands for Minnesota is...

Design of a Field Raised-Bed Trough System using Soilless Substrates for Strawberry Production in California

USDA-ARS?s Scientific Manuscript database

There are a number of approaches for producing strawberry fruit on a commercial scale without fumigants. One possible approach is to grow strawberries using raised-bed troughs filled with non soil based substrate media. Field trials were conducted using peat, perlite, coir, rice hull, and a redwoo...

n-Alkane distributions as indicators of novel ecosystem development in western boreal forest soils

NASA Astrophysics Data System (ADS)

Norris, Charlotte; Dungait, Jennifer; Quideau, Sylvie

2013-04-01

Novel ecosystem development is occurring within the western boreal forest of Canada due to land reclamation following surface mining in the Athabasca Oil Sands Region. Sphagnum peat is the primary organic matter amendment used to reconstruct soils in the novel ecosystems. We hypothesised that ecosystem recovery would be indicated by an increasing similarity in the biomolecular characteristics of novel reconstructed soil organic matter (SOM) derived from peat to those of natural boreal ecosystems. In this study, we evaluated the use of the homologous series of very long chain (>C20) n-alkanes with odd-over-even predominance as biomarker signatures to monitor the re-establishment of boreal forests on reconstructed soils. The lipids were extracted from dominant vegetation inputs and SOM from a series of natural and novel ecosystem reference plots. We observed unique very long n-alkane signatures of the source vegetation, e.g. Sphagnum sp. was dominated by C31 and aspen (Populus tremuloides Michx.) leaves by C25. Greater concentrations of very long chain n-alkanes were extracted from natural than novel ecosystem SOM (p<0.01), and their distribution differed between the two systems (p<0.001) and reflected the dominant vegetation input. Our results indicate that further research is required to clarify the influence of vegetation or disturbance on the signature of very long chain n-alkanes in SOM; however, the use of n-alkanes as biomarkers of ecosystem development is a promising method.

Ubiquitous production of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in global marine environments: a new source indicator for brGDGTs

NASA Astrophysics Data System (ADS)

Xiao, Wenjie; Wang, Yinghui; Zhou, Shangzhe; Hu, Limin; Yang, Huan; Xu, Yunping

2016-10-01

Presumed source specificity of branched glycerol dialkyl glycerol tetraethers (brGDGTs) from bacteria thriving in soil/peat and isoprenoid GDGTs (iGDGTs) from aquatic organisms led to the development of several biomarker proxies for biogeochemical cycle and paleoenvironmental reconstructions. However, recent studies reveal that brGDGTs are also produced in aquatic environments besides soils and peat. Here we examined three cores from the Bohai Sea, and found distinct difference in brGDGT compositions varying with the distance from the Yellow River mouth. We thus propose an abundance ratio of hexamethylated to pentamethylated brGDGT (IIIa / IIa) to evaluate brGDGT sources. The compilation of globally distributed 1354 marine sediments and 589 soils shows that the IIIa / IIa ratio is generally < 0.59 in soils and 0.59-0.92 and > 0.92 in marine sediments with and without significant terrestrial inputs, respectively. Such disparity confirms the existence of two sources for brGDGTs, a terrestrial origin with lower IIIa / IIa and a marine origin with higher IIIa / IIa, which is likely attributed to a generally higher pH and the production of brGDGTs in cold deep water in marine waters. The application of the IIIa / IIa ratio to the East Siberian Arctic Shelf proves it to be a sensitive source indicator for brGDGTs, which is helpful for accurate estimation of organic carbon source and paleoclimates in marine settings.

Vanadium in landscape components of western Transbaikalia

NASA Astrophysics Data System (ADS)

Kashin, V. K.

2017-10-01

Vanadium in soil-forming rocks, soils, and vegetation of forest-steppe, steppe, and dry-steppe landscapes of Transbaikalia has been studied. The mean element contents in rocks and soils are equal to its mean natural abundances (clarke values). The content of vanadium in soils is strictly determined by its content in parent materials; its dependence on the vanadium concentration in plants and on the soil pH and humus is less pronounced. With respect to the coefficient of biological uptake by plants, vanadium is assigned to the group of elements of slight accumulation (0.10-0.33) on mineral soils and of moderate accumulation (1.1-1.5) on peat bog soils. The mean vanadium concentration in steppe, meadow, and cultivated vegetation exceeds the norm for animals by 1.7-2.6 times but does not rich toxic levels. Vanadium uptake by plants is most intensive in meadow cenoses and is less intensive in dry-steppe cenoses.

Coal ball formation and a soil extinction near the P-Tr boundary

NASA Astrophysics Data System (ADS)

Breecker, D.; Royer, D. L.

2017-12-01

Coal balls are calcium carbonate accumulations that commonly permineralize paleotropical PermoCarboniferous coal deposits and preserve exceptional specimens of the coal swamp flora. A widely applicable model for the origin of coal balls is lacking despite the study of these deposits for over a century. Two characteristics of coal balls have been particularly challenging to explain: 1) their temporal range is restricted to the PermoCarboniferous and 2) their typical oxygen isotope and elemental compositions paradoxically indicate freshwater and marine origins, respectively. We propose a new model for coal ball formation. The first step in our model is the episodic delivery of seawater and marine carbonate sediment to coastal mires. Next, these waters are diluted by freshwater and the carbonates dissolve at the elevated pCO2 of the mire subsurface. Finally, as waters flow laterally through stands of arborescent lycopsids, aqueous CO2 in the pore spaces of the peat escapes by diffusion through the air-filled lycopsid rootlets into the overlying water column, where some rootlets are thought to have extended. The CO2 escape drives calcite precipitation in the soil zone. This model explains the narrow temporal occurrence of coal balls, which coincides with the peak diversity of arborescent lycopsids. It also resolves the geochemical conundrum; dilution by freshwater can result in relatively low pore water δ18O values without preventing high-Mg calcite formation. Furthermore, we show mathematically that for published densities of arborescent lycopsid root mats and for reasonable rates of lateral water flow and vertical peat accumulation, CO2 could escape rapidly enough through the rootlets to fill >35% of the porosity with calcite before substantial burial (top several decimeters of peat), explaining the exceptional preservation of coal swamp flora. Therefore, we suggest that coal balls are pedogenic in origin and that their disappearance from the rock record represents the first documented soil extinction on a vegetated planet.

Short-Term Summer Inundation as a Measure to Counteract Acidification in Rich Fens

PubMed Central

Mettrop, Ivan S.; Cusell, Casper; Kooijman, Annemieke M.; Lamers, Leon P. M.

2015-01-01

In regions with intensive agriculture, water level fluctuation in wetlands has generally become constricted within narrow limits. Water authorities are, however, considering the re-establishment of fluctuating water levels as a management tool in biodiverse, base-rich fens (‘rich fens’). This includes temporary inundation with surface water from ditches, which may play an important role in counteracting acidification in order to conserve and restore biodiversity. Inundation may result in an increased acid neutralizing capacity (ANC) for two reasons: infiltration of base-rich inundation water into peat soils, and microbial alkalinity generation under anaerobic conditions. The main objectives of this study were to test whether short-term (2 weeks) summer inundation is more effective than short-term winter inundation to restore the ANC in the upper 10 cm of non-floating peat soils, and to explain potential differences. Large-scale field experiments were conducted for five years in base-rich fens and Sphagnum-dominated poor fens. Winter inundation did not result in increased porewater ANC, because infiltration was inhibited in the waterlogged peat and evapotranspiration rates were relatively low. Also, low temperatures limit microbial alkalinity generation. In summer, however, when temperature and evapotranspiration rates are higher, inundation resulted in increased porewater Ca and HCO3 - concentrations, but only in areas with characteristic rich fen bryophytes. This increase was not only due to stronger infiltration into the soil, but also to higher microbial alkalinity generation under anaerobic conditions. In contrast, porewater ANC did not increase in Sphagnum-plots as a result of the ability of Sphagnum spp. to acidify their environment. In both rich and poor fens, flooding-induced P-mobilization remained sufficiently low to safeguard P-limited vegetation. NO3 - and NH4 + dynamics showed no considerable changes either. In conclusion, short-term summer inundation with base-rich and nutrient-poor surface water is considered beneficial in the management of non-floating rich fens, and much more effective than winter inundation. PMID:26637121

Controls on the chemistry of runoff from an upland peat catchment

NASA Astrophysics Data System (ADS)

Worrall, Fred; Burt, Tim; Adamson, John

2003-07-01

This study uses 2 years of data from a detailed weekly water sampling programme in a 11·4 km2 upland peat catchment in the Northern Pennines, UK. The sampling comprised precipitation, soil-water samples and a number of streams, including the basin outlet. Samples were analysed for: pH, conductivity, alkalinity, Na, K, Ca, Mg, Fe, Al, Total N, SO4, Cl and colour. Principal component analysis (PCA) was used to identify end-members and compositional trends in order to identify controls on the development of water composition. The study showed that the direct use of PCA had several advantages over the use of end-member mixing analysis (EMMA) as it combines an analysis of mixing and evolving waters without the assumption of having to know the compositional sources of the water. In its application to an upland peat catchment, the study supports the view that shallow throughflow at the catotelm/acrotelm boundary is responsible for storm runoff generation and shows that baseflow is controlled by cation exchange in the catotelm and mixing with a base-rich groundwater.

Mitigating Settlement of Structures founded on Peat

NASA Astrophysics Data System (ADS)

Wijeyesekera, D. C.; Numbikannu, L.; Ismail, T. N. H. T.; Bakar, I.

2016-07-01

Observations made of two common failures of structures founded on peat/organic soil in Johor, Malaysia is presented. Critical evaluation of current lightweight fill technology to mitigate such settlement is also discussed. Lightweight technology, such as Expanded Polystyrene (EPS), has been used in construction on soft yielding ground for decades. Regrettably, some published information of EPS failures to perform on construction sites are also cited in this paper. This paper outlines some concepts leading to the development of an alternative innovative lightweight fill is that the idealised cellular structure of the GCM permit free flow of water and complemented by the mat structure which evens out any differential settlement A further highlight of this paper is the monitoring of the field performance of this lightweight fill (GCM) as a feasible alternative to fill weight reduction on yielding ground.. Hence, a prime research objective was to compare the fill settlements observed with 1m high fill of surcharge loading on peat ground (comparison of the case of using a partial 0.6m high GCM and that of a total of 1m of conventional sand backfill).

Plant regulation of greenhouse gas emissions and carbon lability in a Neotropical peatland

NASA Astrophysics Data System (ADS)

Girkin, Nicholas; Vane, Christopher; Turner, Benjamin; Ostle, Nicholas; Sjogersten, Sofie

2017-04-01

Tropical peatlands are under significant threat from land use changes but there remains a significant knowledge gap regarding the influences of contrasting plant types on greenhouse gas emissions and belowground carbon dynamics. We investigated differences in surface CO2 and CH4 fluxes and differences in soil organic carbon chemistry under contrasting surface vegetation types, a palm (Raphia taedigera) and a broadleaved evergreen tree (Campnosperma panamensis), in a Neotropical peatland. CO2 and CH4 production differed significantly between species, with higher fluxes measured under R. taedigera. There were significant differences in peat carbon properties under each species as revealed by Rock-Eval pyrolysis. Peat from under each species showed contrasting trends in degradation inside and outside the rooting zone, and strong differences in the presence of the most labile fractions of carbon. These results highlight the strong impacts that surface vegetation can have on surface gas emissions as well as the influences exerted on peat carbon chemistry within a tropical forested peatland, with implications for our understanding of changes in land use type across the tropics.

River Export of Dissolved and Particulate Organic Carbon from Permafrost and Peat Deposits across the Siberian Arctic

NASA Astrophysics Data System (ADS)

Wild, B.; Andersson, A.; Bröder, L.; Vonk, J.; Hugelius, G.; McClelland, J. W.; Raymond, P. A.; Gustafsson, O.

2017-12-01

Permafrost and peat deposits of northern high latitudes store more than 1300 Pg of organic carbon. This carbon has been preserved for thousands of years by cold and moist conditions, but is now increasingly mobilized as temperatures rise. While part will be degraded to CO2 and CH4 and amplify global warming, part will be exported by rivers to the Arctic Ocean where it can be degraded or re-buried by sedimentation. We here use the four large Siberian rivers Ob, Yenisey, Lena, and Kolyma as natural integrators of carbon mobilization in their catchments. We apply isotope based source apportionments and Markov Chain Monte Carlo Simulations to quantify contributions of organic carbon from permafrost and peat deposits to organic carbon exported by these rivers. More specifically, we compare the 14C signatures of dissolved and particulate organic carbon (DOC, POC) sampled close to the river mouths with those of five potential carbon sources; (1) recent aquatic and (2) terrestrial primary production, (3) the active layer of permafrost soils, (4) deep Holocene deposits (including thermokarst and peat deposits) and (5) Ice Complex Deposits. 14C signatures of these endmembers were constrained based on extensive literature review. We estimate that the four rivers together exported 2.4-4.5 Tg organic carbon from permafrost and peat deposits per year. While total organic carbon export was dominated by DOC (90%), the export of organic carbon from permafrost and peat deposits was more equally distributed between DOC (56%) and POC (44%). Recent models predict that ca. 200 Pg carbon will be lost as CO2 or CH4 by 2100 (RCP8.5) from the circumarctic permafrost area, of which roughly a quarter is drained by the Ob, Yenisey, Lena, and Kolyma rivers. Our comparatively low estimates of river carbon export thus suggest limited transfer of organic carbon from permafrost and peat deposits to high latitude rivers, or its rapid degradation within rivers. Our findings highlight the importance of both DOC and POC, and its degradation, for the fate of carbon mobilized from high latitude deposits under global warming, and indicate a low potential for its stabilization in the Arctic Ocean.

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 oxidation-reduction (redox) status, and mercury methylation potential, of the peat in response to warming and enhanced carbon dioxide.

An expert system model for mapping tropical wetlands and peatlands reveals South America as the largest contributor.

PubMed

Gumbricht, Thomas; Roman-Cuesta, Rosa Maria; Verchot, Louis; Herold, Martin; Wittmann, Florian; Householder, Ethan; Herold, Nadine; Murdiyarso, Daniel

2017-09-01

Wetlands are important providers of ecosystem services and key regulators of climate change. They positively contribute to global warming through their greenhouse gas emissions, and negatively through the accumulation of organic material in histosols, particularly in peatlands. Our understanding of wetlands' services is currently constrained by limited knowledge on their distribution, extent, volume, interannual flood variability and disturbance levels. We present an expert system approach to estimate wetland and peatland areas, depths and volumes, which relies on three biophysical indices related to wetland and peat formation: (1) long-term water supply exceeding atmospheric water demand; (2) annually or seasonally water-logged soils; and (3) a geomorphological position where water is supplied and retained. Tropical and subtropical wetlands estimates reach 4.7 million km 2 (Mkm 2 ). In line with current understanding, the American continent is the major contributor (45%), and Brazil, with its Amazonian interfluvial region, contains the largest tropical wetland area (800,720 km 2 ). Our model suggests, however, unprecedented extents and volumes of peatland in the tropics (1.7 Mkm 2 and 7,268 (6,076-7,368) km 3 ), which more than threefold current estimates. Unlike current understanding, our estimates suggest that South America and not Asia contributes the most to tropical peatland area and volume (ca. 44% for both) partly related to some yet unaccounted extended deep deposits but mainly to extended but shallow peat in the Amazon Basin. Brazil leads the peatland area and volume contribution. Asia hosts 38% of both tropical peat area and volume with Indonesia as the main regional contributor and still the holder of the deepest and most extended peat areas in the tropics. Africa hosts more peat than previously reported but climatic and topographic contexts leave it as the least peat-forming continent. Our results suggest large biases in our current understanding of the distribution, area and volumes of tropical peat and their continental contributions. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Experimental modeling of thaw lake water evolution in discontinuous permafrost zone: Role of peat, lichen leaching and ground fire.

PubMed

Manasypov, Rinat M; Shirokova, Liudmila S; Pokrovsky, Oleg S

2017-02-15

Thaw of frozen peat in discontinuous permafrost zone produces a significant number of thermokarst lakes, which are known to contribute to Green House Gases (GHG) emission in the atmosphere. In palsa peatland of western Siberia, the thermokarst lake formation includes soil subsidences, lichen submergence and peat abrasion, leading to lateral spreading of the lake border, often intensified by ground fires. Mesocosm experiments were conducted during 3weeks on two thermokarst lake waters interacting in 30-L tanks with surface horizon of peat, the dominant ground vegetation (lichen Cladonia sp.) and the ash produced by lichen burning at 450°C. The obtained results allowed a better understanding of physico-chemical factors controlling the enrichment of thermokarst lake water in organic carbon and metals, and evaluating CO 2 sequestration/emission potential. The changes of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC), major element and divalent metal concentration in response to peat and lichen biomass addition were less than a factor of 2 over full duration of the experiment. Iron (Fe) concentration in the lake water decreased by a factor of 2 to 3 after the addition of peat and lichen biomass. The concentration of low-soluble trivalent and tetravalent hydrolysates decreased by ca. 30 to 50%, presumably due to their co-precipitation with Fe hydroxide. The dissolved carbon dioxide (CO 2 ) in tank with lichen increased by a factor of 5.5±0.5, likely due to respiration of algal component in closed environment. Strong enrichment of the lake water in DIC, P, K, Ca, Mg, Si, Al, Ti, Mn, Mo, Rb, As, Sb and U upon the ash addition persisted over full duration of experiments and was significant (p<0.0001) compared to peat and lichen biomass treatments. These elements may serve as indicators of ground fire impact on thermokarst lake water's chemistry. The overall effect of ash leaching on aquatic ecosystems after ground fire of frozen Siberian peatland is predicted to be much stronger than that currently recognized for non-permafrost regions. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of diversity of diazotrophic bacteria associated with the rhizosphere of a tropical Arbor, Melastoma malabathricum L.

PubMed

Sato, Atsuya; Watanabe, Toshihiro; Unno, Yusuke; Purnomo, Erry; Osaki, Mitsuru; Shinano, Takuro

2009-01-01

The diversity of diazotrophic bacteria in the rhizosphere of Melastoma malabathricum L. was investigated by cloning-sequencing of the nifH gene directly amplified from DNA extracted from soil. Samples were obtained from the rhizosphere and bulk soil of M. malabathricum growing in three different soil types (acid sulfate, peat and sandy clay soils) located very close to each other in south Kalimantan, Indonesia. Six clone libraries were constructed, generated from bulk and rhizosphere soil samples, and 300 nifH clones were produced, then assembled into 29 operational taxonomic units (OTUs) based on percent identity values. Our results suggested that nifH gene diversity is mainly dependent on soil properties, and did not differ remarkably between the rhizosphere and bulk soil of M. malabathricum except in acid sulfate soil. In acid sulfate soil, as the Shannon diversity index was lower in rhizosphere than in bulk soil, it is suggested that particular bacterial species might accumulate in the rhizosphere.

Vulnerability of North American Boreal Peatlands to Interactions between Climate, Hydrology, and Wildland Fires

NASA Astrophysics Data System (ADS)

Bourgeau-Chavez, L. L.; Jenkins, L. K.; Kasischke, E. S.; Turetsky, M.; Benscoter, B.; Banda, E. J.; Boren, E. J.; Endres, S. L.; Billmire, M.

2013-12-01

North American boreal peatland sites of Alaska, Alberta Canada, and the southern limit of the boreal ecoregion (Michigan's Upper Peninsula) are the focus of an ongoing project to better understand the fire weather, hydrology, and climatic controls on boreal peatland fires. The overall goal of the research project is to reduce uncertainties of the role of northern high latitude ecosystems in the global carbon cycle and to improve carbon emission estimates from boreal fires. Boreal peatlands store tremendous reservoirs of soil carbon that are likely to become increasingly vulnerable to fire as climate change lowers water tables and exposes C-rich peat to burning. Increasing fire activity in peatlands could cause these ecosystems to become net sources of C to the atmosphere, which is likely to have large influences on atmospheric carbon concentrations through positive feedbacks that enhance climate warming. Remote sensing is key to monitoring, understanding and quantifying changes occurring in boreal peatlands. Remote sensing methods are being developed to: 1) map and classify peatland cover types; 2) characterize seasonal and inter-annual variations in the moisture content of surface peat (fuel) layers; 3) map the extent and seasonal timing of fires in peatlands; and 4) discriminate different levels of fuel consumption/burn severity in peat fires. A hybrid radar and optical infrared methodology has been developed to map peatland types (bog vs. fen) and level of biomass (open herbaceous, shrubby, forested). This methodology relies on multi-season data to detect phenological changes in hydrology which characterize the different ecosystem types. Landsat data are being used to discriminate burn severity classes in the peatland types using standard dNBR methods as well as individual bands. Cross referencing the peatland maps and burn severity maps will allow for assessment of the distribution of upland and peatland ecosystems affected by fire and quantitative analysis of emissions. Radar imagery from multiple platforms (L-band PALSAR, C-band ERS-2, Envisat, and Radarsat-2) is being used to develop soil moisture extraction algorithms to monitor changes (drying - wetting) through time and to develop a standard method for soil moisture assessment. Using data from the 1990s (ERS-1 and 2) through the present (Radarsat-2) will allow for determination of patterns of wetting and drying across the landscape. All the remote sensing analysis is supported with field work which has been coordinated with that of Canadian scientists. Field collection includes vegetation and hydrology data to validate peatland distribution maps, collection of water table depths and peat moisture content data to aid in algorithm development for radar organic soil moisture retrieval, and characterization of variations in depth of burning and carbon consumption during peatland fires to use in burn severity mapping and fire emissions modeling.

Observational and modeling constraints on global anthropogenic enrichment of mercury.

PubMed

Amos, Helen M; Sonke, Jeroen E; Obrist, Daniel; Robins, Nicholas; Hagan, Nicole; Horowitz, Hannah M; Mason, Robert P; Witt, Melanie; Hedgecock, Ian M; Corbitt, Elizabeth S; Sunderland, Elsie M

2015-04-07

Centuries of anthropogenic releases have resulted in a global legacy of mercury (Hg) contamination. Here we use a global model to quantify the impact of uncertainty in Hg atmospheric emissions and cycling on anthropogenic enrichment and discuss implications for future Hg levels. The plausibility of sensitivity simulations is evaluated against multiple independent lines of observation, including natural archives and direct measurements of present-day environmental Hg concentrations. It has been previously reported that pre-industrial enrichment recorded in sediment and peat disagree by more than a factor of 10. We find this difference is largely erroneous and caused by comparing peat and sediment against different reference time periods. After correcting this inconsistency, median enrichment in Hg accumulation since pre-industrial 1760 to 1880 is a factor of 4.3 for peat and 3.0 for sediment. Pre-industrial accumulation in peat and sediment is a factor of ∼ 5 greater than the precolonial era (3000 BC to 1550 AD). Model scenarios that omit atmospheric emissions of Hg from early mining are inconsistent with observational constraints on the present-day atmospheric, oceanic, and soil Hg reservoirs, as well as the magnitude of enrichment in archives. Future reductions in anthropogenic emissions will initiate a decline in atmospheric concentrations within 1 year, but stabilization of subsurface and deep ocean Hg levels requires aggressive controls. These findings are robust to the ranges of uncertainty in past emissions and Hg cycling.

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.

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

NASA Astrophysics Data System (ADS)

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

2014-01-01

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

Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates

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

Bhattacharyya, Amrita; Schmidt, Michael P.; Stavitski, Eli

The speciation of iron (Fe) in organic matter (OM)-rich environments under in situ variable redox conditions is largely unresolved. Peatlands provide a natural setting to study Fe–OM interactions. Utilizing chemical, spectroscopic and theoretical modeling approaches, we report the chemical forms, oxidation states and local coordination environment of naturally occurring Fe in the vertically redox-stratified Manning peatlands of western New York. In addition, we report dominant carbon, sulfur and nitrogen species that can potentially stabilize the various Fe species present in these peatlands. Our results provide clear direct and indirect evidence for the co-occurrence of ferrous (Fe 2+) and ferric (Femore » 3+) iron species in peats under both oxic and anoxic conditions. Iron is mostly present within the operationally defined organic and amorphous (i.e., short range ordered, SRO) fractions; ferric iron primarily as magnetically isolated paramagnetic Fe 3+ in Fe(III)-organic complexes, but also in mineral forms such as ferrihydrite; ferrous iron in tetrahedral coordination in Fe(II)-organic complexes with minor contribution from pyrite. All of the Fe species identified stabilize Fe(III) and/or Fe(II) in anoxic and oxic peats. Fundamental differences are also observed in the relative proportion of C, S and N functionalities of OM in oxic and anoxic peats. Aromatic C=C, ester, phenol and anomeric C (R-O-C-O-R), as well as thiol, sulfide and heterocyclic N functionalities are more prevalent in anoxic peats. Collectively, our experimental evidence suggests iron forms coordination complexes with O-, S- and N-containing functional groups of OM. We posit the co-occurrence of organic and mineral forms of Fe(II) and Fe(III) in both oxic and anoxic peat layers results from dynamic complexation and hydrolysis-precipitation reactions that occur under variable redox conditions. In conclusion, our findings aid in understanding the crucial role OM plays in determining Fe species in soils and sediments.« less

Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates

DOE PAGES

Bhattacharyya, Amrita; Schmidt, Michael P.; Stavitski, Eli; ...

2017-10-31

The speciation of iron (Fe) in organic matter (OM)-rich environments under in situ variable redox conditions is largely unresolved. Peatlands provide a natural setting to study Fe–OM interactions. Utilizing chemical, spectroscopic and theoretical modeling approaches, we report the chemical forms, oxidation states and local coordination environment of naturally occurring Fe in the vertically redox-stratified Manning peatlands of western New York. In addition, we report dominant carbon, sulfur and nitrogen species that can potentially stabilize the various Fe species present in these peatlands. Our results provide clear direct and indirect evidence for the co-occurrence of ferrous (Fe 2+) and ferric (Femore » 3+) iron species in peats under both oxic and anoxic conditions. Iron is mostly present within the operationally defined organic and amorphous (i.e., short range ordered, SRO) fractions; ferric iron primarily as magnetically isolated paramagnetic Fe 3+ in Fe(III)-organic complexes, but also in mineral forms such as ferrihydrite; ferrous iron in tetrahedral coordination in Fe(II)-organic complexes with minor contribution from pyrite. All of the Fe species identified stabilize Fe(III) and/or Fe(II) in anoxic and oxic peats. Fundamental differences are also observed in the relative proportion of C, S and N functionalities of OM in oxic and anoxic peats. Aromatic C=C, ester, phenol and anomeric C (R-O-C-O-R), as well as thiol, sulfide and heterocyclic N functionalities are more prevalent in anoxic peats. Collectively, our experimental evidence suggests iron forms coordination complexes with O-, S- and N-containing functional groups of OM. We posit the co-occurrence of organic and mineral forms of Fe(II) and Fe(III) in both oxic and anoxic peat layers results from dynamic complexation and hydrolysis-precipitation reactions that occur under variable redox conditions. In conclusion, our findings aid in understanding the crucial role OM plays in determining Fe species in soils and sediments.« less

Organic matter transformation in the peat column at Marcell Experimental Forest: Humification and vertical stratification

NASA Astrophysics Data System (ADS)

Tfaily, Malak M.; Cooper, William T.; Kostka, Joel E.; Chanton, Patrick R.; Schadt, Christopher W.; Hanson, Paul J.; Iversen, Colleen M.; Chanton, Jeffrey P.

2014-04-01

We characterized peat decomposition at the Marcell Experimental Forest (MEF), Minnesota, USA, to a depth of 2 m to ascertain the underlying chemical changes using Fourier transform infrared (FT IR) and 13C nuclear magnetic resonance (NMR) spectroscopy) and related these changes to decomposition proxies C:N ratio, δ13C and δ15N, bulk density, and water content. FT IR determined that peat humification increased rapidly between 30 and 75 cm, indicating a highly reactive intermediate-depth zone consistent with changes in C:N ratio, δ13C and δ15N, bulk density, and water content. Peat decomposition at the MEF, especially in the intermediate-depth zone, is mainly characterized by preferential utilization of O-alkyl-C, carboxyl-C, and other oxygenated functionalities with a concomitant increase in the abundance of alkyl- and nitrogen-containing compounds. Below 75 cm, less change was observed but aromatic functionalities and lignin accumulated with depth. Significant correlations with humification indices, identified by FT IR spectroscopy, were found for C:N ratios. Incubation studies at 22°C revealed the highest methane production rates, greatest CH4:CO2 production ratios, and significant O-alkyl-C utilization within this 30 and 75 cm zone. Oxygen-containing functionalities, especially O-alkyl-C, appear to serve as excellent proxies for soil decomposition rate and should be a sensitive indicator of the response of the solid phase peat to increased temperatures caused by climate change and the field study manipulations that are planned to occur at this site. Radiocarbon signatures of microbial respiration products in deeper pore waters at the MEF resembled the signatures of more modern dissolved organic carbon rather than solid phase peat, indicating that recently photosynthesized organic matter fueled the bulk of subsurface microbial respiration. These results indicate that carbon cycling at depth at the MEF is not isolated from surface processes.

Simulated climate change impact on summer dissolved organic carbon release from peat and surface vegetation: implications for drinking water treatment.

PubMed

Ritson, Jonathan P; Bell, Michael; Graham, Nigel J D; Templeton, Michael R; Brazier, Richard E; Verhoef, Anne; Freeman, Chris; Clark, Joanna M

2014-12-15

Uncertainty regarding changes in dissolved organic carbon (DOC) quantity and quality has created interest in managing peatlands for their ecosystem services such as drinking water provision. The evidence base for such interventions is, however, sometimes contradictory. We performed a laboratory climate manipulation using a factorial design on two dominant peatland vegetation types (Calluna vulgaris and Sphagnum Spp.) and a peat soil collected from a drinking water catchment in Exmoor National Park, UK. Temperature and rainfall were set to represent baseline and future conditions under the UKCP09 2080s high emissions scenario for July and August. DOC leachate then underwent standard water treatment of coagulation/flocculation before chlorination. C. vulgaris leached more DOC than Sphagnum Spp. (7.17 versus 3.00 mg g(-1)) with higher specific ultraviolet (SUVA) values and a greater sensitivity to climate, leaching more DOC under simulated future conditions. The peat soil leached less DOC (0.37 mg g(-1)) than the vegetation and was less sensitive to climate. Differences in coagulation removal efficiency between the DOC sources appears to be driven by relative solubilisation of protein-like DOC, observed through the fluorescence peak C/T. Post-coagulation only differences between vegetation types were detected for the regulated disinfection by-products (DBPs), suggesting climate change influence at this scale can be removed via coagulation. Our results suggest current biodiversity restoration programmes to encourage Sphagnum Spp. will result in lower DOC concentrations and SUVA values, particularly with warmer and drier summers. Copyright © 2014 Elsevier Ltd. All rights reserved.

Spatiotemporal variability in biogenic gas dynamics in a subtropical peat soil at the laboratory scale is revealed using high-resolution ground-penetrating radar

NASA Astrophysics Data System (ADS)

Mustasaar, Mario; Comas, Xavier

2017-09-01

The importance of peatlands as sources of greenhouse gas emissions has been demonstrated in many studies during the last two decades. While most studies have shown the heterogeneous distribution of biogenic gas in peat soils at the field scale (sampling volumes in the order of meters), little information exists for submeter scales, particularly relevant to properly capture the dynamics of hot spots for gas accumulation and release when designing sampling routines with methods that use smaller (i.e., submeter) sampling volumes like flux chambers. In this study, ground-penetrating radar is used at the laboratory scale to evaluate biogenic gas dynamics at high spatial resolution (i.e., cm) in a peat monolith from the Everglades. The results indicate sharp changes (both spatially and temporally) in the dynamics of gas accumulation and release, representing hot spots for production and release of biogenic gases with surface areas ranging between 5 to 10 cm diameter and are associated with increases in porosity. Furthermore, changes in gas composition and inferred methane (CH4) and carbon dioxide (CO2) fluxes also displayed a high spatiotemporal variability associated with hot spots, resulting in CH4 and CO2 flux estimates showing differences up to 1 order of magnitude during the same day for different parts of the sample. This work follows on recent studies in the Everglades and questions the appropriateness of spatial and temporal scales of measurement when defining gas dynamics by showing how flux values may change both spatially and temporarily even when considering submeter spatial scales.

A pore-size classification for peat bogs derived from unsaturated hydraulic properties

NASA Astrophysics Data System (ADS)

Weber, Tobias Karl David; Iden, Sascha Christian; Durner, Wolfgang

2017-12-01

In ombrotrophic peatlands, the moisture content of the acrotelm (vadoze zone) controls oxygen diffusion rates, redox state, and the turnover of organic matter. Thus, variably saturated flow processes determine whether peatlands act as sinks or sources of atmospheric carbon, and modelling these processes is crucial to assess effects of changed environmental conditions on the future development of these ecosystems. We show that the Richards equation can be used to accurately describe the moisture dynamics under evaporative conditions in variably saturated peat soil, encompassing the transition from the topmost living moss layer to the decomposed peat as part of the vadose zone. Soil hydraulic properties (SHP) were identified by inverse simulation of evaporation experiments on samples from the entire acrotelm. To obtain consistent descriptions of the observations, the traditional van Genuchten-Mualem model was extended to account for non-capillary water storage and flow. We found that the SHP of the uppermost moss layer reflect a pore-size distribution (PSD) that combines three distinct pore systems of the Sphagnum moss. For deeper samples, acrotelm pedogenesis changes the shape of the SHP due to the collapse of inter-plant pores and an infill with smaller particles. This leads to gradually more homogeneous and bi-modal PSDs with increasing depth, which in turn can serve as a proxy for increasing state of pedogenesis in peatlands. From this, we derive a nomenclature and size classification for the pore spaces of Sphagnum mosses and define inter-, intra-, and inner-plant pore spaces, with effective pore diameters of > 300, 300-30, and 30-10 µm, respectively.

The geology, botany and chemistry of selected peat-forming environments from temperate and tropical latitudes

USGS Publications Warehouse

Cameron, C.C.; Esterle, J.S.; Palmer, C.A.

1989-01-01

Peat has been studied in several geologic settings: (1) glaciated terrain in cold temperate Maine and Minnesota, U.S.A.; (2) an island in the Atlantic Ocean off the coast of Maine, where sea level is rising; (3) the warm temperate U.S. Atlantic and Gulf Coastal Plains, where sea level has changed often; and (4) the tropical coast of Sarawak, Malaysia, and the tropical delta of the Batang Hari River, Sumatra, Indonesia. Most of these deposits are domed (ombrotrophic or partly ombrotrophic) bogs in which peat accumulation continued above the surface of the surrounding soil. However, the bogs of the U.S. Atlantic and Gulf Coastal Plains are comparatively not as domed, and many have almost level surfaces. In some bogs, aquatic or semi-aquatic plant materials accumulated, replaced water in the depressions, and formed a surface on which marsh or swamp vegetation could subsequently live, die, and accumulate. In others, the plant materials accumulated initially on level silt or sand surfaces supporting marshes or swamps. As the peat dome formed, plants growing on it changed from luxuriant ones near the base of the dome, where nutrients were brought into the bog by surface and ground water, to stunted ones at the top of the dome, where the raised bogs are fed by nutrient-poor precipitation. The physical and chemical changes that take place in the sequence of environments from the pond stage of deposit development, through the grassy marsh stage, through the forested swamp stage, and finally through the heath dome stage can be measured in terms of acidity and ash, volatile matter, carbon, hydrogen, nitrogen, sulfur and oxygen contents, as well as in the kind and distribution of trace elements. The organic and inorganic contents of the deposits relate to geomorphology, and geomorphology relates to their settings. As models of coal formation, some domed peat deposits may help in solving problems of distribution and character of ancient coal beds. But clearly not all peat deposits are precursors of coal. Most Holocene peat deposits are subject to destruction by erosion, fire and decomposition through microbial and chemical oxidation before burial. The best environments for coal precursors have biomass accumulation, a continuously rising water table within the mass, and minimum influx of clay and silt until preservation by burial. The most suitable settings for future economic coal deposits are domed bogs that accumulate thick, widespread peat having low ash and low sulfur contents. The ombrotrophic peat deposits of tropical Sarawak and Sumatra are thick and extensive, contain low-ash and low-sulfur peat, and have high heating values. They are considered to be the best tropical coal analogs because of their extent and chances of preservation; the base of the peat is below adjacent river levels, and chemical and structural conditions are favorable for accumulation. ?? 1989.

Forms and accumulation of soil P in natural and recently restored peatlands - Upper Klamath Lake, Oregon, USA

USGS Publications Warehouse

Graham, S.A.; Craft, C.B.; McCormick, P.V.; Aldous, A.

2005-01-01

Forms, amounts, and accumulation of soil phosphorus (P) were measured in natural and recently restored marshes surrounding Upper Klamath Lake located in south-central Oregon, USA to determine rates of P accumulation in natural marshes and to assess changes in P pools caused by long-term drainage in recently restored marshes. Soil cores were collected from three natural marshes and radiometrically dated to determine recent (l37Cs-based) and long-term (210Pb-based) rates of peat accretion and P accumulation. A second set of soil cores collected from the three natural marshes and from three recently restored marshes was analyzed using a modification of the Hedley procedure to determine the forms and amounts of soil P. Total P in the recently restored marshes (222 to 311 ??g cm-3) was 2-3 times greater than in the natural marshes (103 to 117 ??g cm-3), primarily due to greater bulk density caused by soil subsidence, a consequence of long-term marsh drainage. Occluded Fe- and Al-bound Pi, calcium-bound Pi and residual P were 4 times, 22 times, and 5 times greater, respectively, in the recently restored marshes. More than 67% of the P pool in both the natural and recently restored marshes was present in recalcitrant forms (humic-acid P o and residual P) that provide long-term P storage in peat. Phosphorus accumulation in the natural marshes averaged 0.45 g m-2 yr-1 (137Cs) and 0.40 g m-2 yr-1 (210Pb), providing a benchmark for optimizing P sequestration in the recently restored marshes. Effective P sequestration in the recently restored marshes, however, will depend on re-establishing equilibrium between the P-enriched soils and the P concentration of floodwaters and a hydrologie regime similar to the natural marshes. ?? 2005, The Society of Wetland Scientists.

Ecohydrology of the wetland-forestland interface: hydrophobicity in leaf litter and its potential effect on surface evaporation

NASA Astrophysics Data System (ADS)

Probert, Samantha; Kettridge, Nicholas; Devito, Kevin; Hurley, Alexander

2017-04-01

Riparian wetlands represent an important ecotone at the interface of peatlands and forests within the Western Boreal Plain of Canada. Water storage and negative feedbacks to evaporation in these systems is crucial for the conservation and redistribution of water during dry periods and providing ecosystem resilience to disturbance. Litter cover can alter the relative importance of the physical processes that drive soil evaporation. Negative feedbacks to drying are created as the hydrophysical properties of the litter and soil override atmospheric controls on evaporation in dry conditions, subsequently dampening the effects of external forcings on the wetland moisture balance. In this study, water repellency in leaf litter has been shown to significantly correlate with surface-atmosphere interactions, whereby severely hydrophobic leaf litter is linked to the highest surface resistances to evaporation, and therefore lowest instantaneous evaporation. Decreasing moisture is associated with increasing hydrophobicity, which may reduce the evaporative flux further as the dry hydrophobic litter creates a hydrological disconnect between soil moisture and the atmosphere. In contrast, hydrophilic litter layers exhibited higher litter moistures, which is associated with reduced resistances to evaporation and enhanced evaporative fluxes. Water repellency of the litter layer has a greater control on evaporation than the presence or absence of litter itself. Litter removal had no significant effect on instantaneous evaporation or surface resistance to evaporation except under the highest evaporation conditions, where litter layers produced higher resistance values than bare peat soils. However, litter removal modified the dominant physical controls on evaporation: moisture loss in plots with leaf litter was driven by leaf and soil hydrophysical properties. Contrastingly, bare peat soils following litter removal exhibited cooler, wetter surfaces and were more strongly correlated to atmospheric controls. The interaction between evaporation, hydrophobicity and moisture of the soil surface, or litter, presents a potentially significant negative feedback to drying across wetland-forestland interfaces.

Identifying sources of acidity and spatial distribution of acid sulfate soils in the Anglesea River catchment, southern Australia

NASA Astrophysics Data System (ADS)

Wong, Vanessa; Yau, Chin; Kennedy, David

2015-04-01

Globally, coastal and estuarine floodplains are frequently underlain by sulfidic sediments. When exposed to oxygen, sulfidic sediments oxidise to form acid sulfate soils, adversely impacting on floodplain health and adjacent aquatic ecoystems. In eastern Australia, our understanding of the formation of these coastal and estuarine floodplains, and hence, spatial distribution of acid sulfate soils, is relatively well established. These soils have largely formed as a result of sedimentation of coastal river valleys approximately 6000 years BP when sea levels were one to two metres higher. However, our understanding of the evolution of estuarine systems and acid sulfate soil formation, and hence, distribution, in southern Australia remains limited. The Anglesea River, in southern Australia, is subjected to frequent episodes of poor water quality and low pH resulting in closure of the river and, in extreme cases, large fish kill events. This region is heavily reliant on tourism and host to a number of iconic features, including the Great Ocean Road and Twelve Apostles. Poor water quality has been linked to acid leakage from mining activities and Tertiary-aged coal seams, peat swamps and acid sulfate soils in the region. However, our understanding of the sources of acidity and distribution of acid sulfate soils in this region remains poor. In this study, four sites on the Anglesea River floodplain were sampled, representative of the main vegetation communities. Peat swamps and intertidal marshes were both significant sources of acidity on the floodplain in the lower catchment. However, acid neutralising capacity provided by carbonate sands suggests that there are additional sources of acidity higher in the catchment. This pilot study has highlighted the complexity in the links between the floodplain, upper catchment and waterways with further research required to understand these links for targeted acid management strategies.