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Sample records for boreal peatland buffer

  1. Methane flux from boreal peatlands

    International Nuclear Information System (INIS)

    Crill, P.; Bartlett, K.; Roulet, N.

    1992-01-01

    The peatlands in the boreal zone (roughly 45 deg - 60 degN) store a significant reservoir of carbon, much of which is potentially available for exchange with the atmosphere. The anaerobic conditions that cause these soils to accumulate carbon also makes wet, boreal peatlands significant sources of methane to the global troposphere. It is estimated that boreal wetlands contribute approximately 19.5 Tg methane per year. The data available on the magnitude of boreal methane emissions have rapidly accumulated in the past twenty years. This paper offers a short review of the flux measured (with range roughly 1 - 2000 mg methane/m2d), considers environmental controls of the flux and briefly discusses how climate change might affect future fluxes

  2. Russian boreal peatlands dominate the natural European methane budget

    International Nuclear Information System (INIS)

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

    2016-01-01

    About 60% of the European wetlands are located in the European part of Russia. Nevertheless, data on methane emissions from wetlands of that area are absent. Here we present results of methane emission measurements for two climatically different years from a boreal peatland complex in European Russia. Winter fluxes were well within the range of what has been reported for the peatlands of other boreal regions before, but summer fluxes greatly exceeded the average range of 5–80 mg CH 4 m −2 d −1 for the circumpolar boreal zone. Half of the measured fluxes ranged between 150 and 450 mg CH 4 m −2 d −1 . Extrapolation of our data to the whole boreal zone of European Russia shows that theses emissions could amount to up to 2.7 ± 1.1 Tg CH 4 a −1 , corresponding to 69% of the annual emissions from European wetlands or 33% of the total annual natural European methane emission. In 2008, climatic conditions corresponded to the long term mean, whereas the summer of 2011 was warmer and noticeably drier. Counterintuitively, these conditions led to even higher CH 4 emissions, with peaks up to two times higher than the values measured in 2008. As Russian peatlands dominate the areal extend of wetlands in Europe and are characterized by very high methane fluxes to the atmosphere, it is evident, that sound European methane budgeting will only be achieved with more insight into Russian peatlands. (letter)

  3. Dominant Tree Species and Soil Type Affect the Fungal Community Structure in a Boreal Peatland Forest

    Science.gov (United States)

    Terhonen, Eeva; Kovalchuk, Andriy; Tuovila, Hanna; Chen, Hongxin; Oghenekaro, Abbot O.; Heinonsalo, Jussi; Kohler, Annegret; Kasanen, Risto; Vasander, Harri; Asiegbu, Fred O.

    2016-01-01

    Boreal peatlands play a crucial role in global carbon cycling, acting as an important carbon reservoir. However, little information is available on how peatland microbial communities are influenced by natural variability or human-induced disturbances. In this study, we have investigated the fungal diversity and community structure of both the organic soil layer and buried wood in boreal forest soils using high-throughput sequencing of the internal transcribed spacer (ITS) region. We have also compared the fungal communities during the primary colonization of wood with those of the surrounding soils. A permutational multivariate analysis of variance (PERMANOVA) confirmed that the community composition significantly differed between soil types (P peatlands; it further provides a baseline for the investigation of the dynamics of the fungal community in the boreal peatlands. PMID:26896139

  4. Mercury evasion from a boreal peatland shortens the timeline for recovery from legacy pollution.

    Science.gov (United States)

    Osterwalder, Stefan; Bishop, Kevin; Alewell, Christine; Fritsche, Johannes; Laudon, Hjalmar; Åkerblom, Staffan; Nilsson, Mats B

    2017-11-22

    Peatlands are a major source of methylmercury that contaminates downstream aquatic food webs. The large store of mercury (Hg) in peatlands could be a source of Hg for over a century even if deposition is dramatically reduced. However, the reliability of Hg mass balances can be questioned due to missing long-term land-atmosphere flux measurements. We used a novel micrometeorological system for continuous measurement of Hg peatland-atmosphere exchange to derive the first annual Hg budget for a peatland. The evasion of Hg (9.4 µg m -2 yr -1 ) over the course of a year was seven times greater than stream Hg export, and over two times greater than wet bulk deposition to the boreal peatland. Measurements of dissolved gaseous Hg in the peat pore water also indicate Hg evasion. The net efflux may result from recent declines in atmospheric Hg concentrations that have turned the peatland from a net sink into a source of atmospheric Hg. This net Hg loss suggests that open boreal peatlands and downstream ecosystems can recover more rapidly from past atmospheric Hg deposition than previously assumed. This has important implications for future levels of methylmercury in boreal freshwater fish and the estimation of historical Hg accumulation rates from peat profiles.

  5. Methylmercury declines in a boreal peatland when experimental sulfate deposition decreases

    Science.gov (United States)

    Jill K. Coleman Wasik; Carl P.J. Mitchell; Daniel R. Engstrom; Edward B. Swain; Bruce A. Monson; Steven J. Balogh; Jeffrey D. Jeremiason; Brian A. Branfireun; Susan L. Eggert; Randall K. Kolka; James E. Almendinger

    2012-01-01

    Between 2001 and 2008 we experimentally manipulated atmospheric sulfate-loading to a small boreal peatland and monitored the resulting short and long-term changes in methylmercury (MeHg) production. MeHg concentrations and %MeHg (fraction of total-Hg (HgT) present as MeHg) in the porewaters of the experimental treatment reached peak values within...

  6. Contribution of vegetation and water table on isoprene emission from boreal peatland microcosms

    DEFF Research Database (Denmark)

    Tiiva, Päivi; Faubert, Patrick; Räty, Sanna

    2009-01-01

    emission in these naturally wet ecosystems, although water table is predicted to decline due to climate warming. We studied the relative contribution of mosses vs. vascular plants to isoprene emission in boreal peatland microcosms in growth chambers by removing either vascular vegetation or both vascular...... hollows with intact vegetation, 45 ± 6 µg m-2 h-1, was decreased by 25% under water table drawdown. However, water table drawdown reduced net ecosystem carbon dioxide (CO2) exchange more dramatically than isoprene emission. Isoprene emission strongly correlated with both CO2 exchange and methane emission......Boreal peatlands are substantial sources of isoprene, a reactive hydrocarbon. However, it is not known how much mosses, vascular plants and peat each contribute to isoprene emission from peatlands. Furthermore, there is no information on the effects of declining water table depth on isoprene...

  7. Characterizing Early Succession Following Wildfires at Different Severities in Boreal Bog and Fen Peatlands

    Science.gov (United States)

    Ernst, E. J.; Bourgeau-Chavez, L. L.; Kane, E. S.; Wagenbrenner, J. W.; Endres, S.

    2016-12-01

    The Arctic-boreal region is experiencing changes in climate, trending toward warmer summers, resulting in a greater occurrence of wildfires with longer burning periods and higher intensities. Drought-like conditions have dried surface fuels, leading to a higher probability of ignition, even in lowland peatlands. Previous work has been done to characterize post-fire succession rates in Arctic-boreal upland sites, but much less is known of fire effects and early successional dynamics in lowlands. Wildland fires are the number one disturbance in Canada's Northwest Territories (NWT), which characteristically burn at high intensities with large flame fronts, and result in some of the biggest wildfires in the world. Areas surrounding the Great Slave Lake, NWT—including parts of the Taiga Plains, Taiga Shield, and Boreal Plains ecozones—experienced exceptional wildfire activity in 2014 and 2015. We characterized burn severity of the bog and fen peat surface and canopy layers at several burned sites. To determine if the severe ground or crown wildfires were stand-replacing events, we characterized post-fire vegetation in peatlands in 2015 and 2016 based on seedling regeneration. We stratified sites according to estimated water residence times across the three ecozones and made comparisons between data collected at the same sites across years. This work adds much needed context for post-fire succession in boreal peatland ecosystems, as the susceptibility of these systems to burning will continue to increase with a warming climate.

  8. Dominant Tree Species and Soil Type Affect the Fungal Community Structure in a Boreal Peatland Forest.

    Science.gov (United States)

    Sun, Hui; Terhonen, Eeva; Kovalchuk, Andriy; Tuovila, Hanna; Chen, Hongxin; Oghenekaro, Abbot O; Heinonsalo, Jussi; Kohler, Annegret; Kasanen, Risto; Vasander, Harri; Asiegbu, Fred O

    2016-05-01

    Boreal peatlands play a crucial role in global carbon cycling, acting as an important carbon reservoir. However, little information is available on how peatland microbial communities are influenced by natural variability or human-induced disturbances. In this study, we have investigated the fungal diversity and community structure of both the organic soil layer and buried wood in boreal forest soils using high-throughput sequencing of the internal transcribed spacer (ITS) region. We have also compared the fungal communities during the primary colonization of wood with those of the surrounding soils. A permutational multivariate analysis of variance (PERMANOVA) confirmed that the community composition significantly differed between soil types (P< 0.001) and tree species (P< 0.001). The distance-based linear models analysis showed that environmental variables were significantly correlated with community structure (P< 0.04). The availability of soil nutrients (Ca [P= 0.002], Fe [P= 0.003], and P [P= 0.003]) within the site was an important factor in the fungal community composition. The species richness in wood was significantly lower than in the corresponding soil (P< 0.004). The results of the molecular identification were supplemented by fruiting body surveys. Seven of the genera of Agaricomycotina identified in our surveys were among the top 20 genera observed in pyrosequencing data. Our study is the first, to our knowledge, fungal high-throughput next-generation sequencing study performed on peatlands; it further provides a baseline for the investigation of the dynamics of the fungal community in the boreal peatlands. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  9. Rain events decrease boreal peatland net CO2 uptake through reduced light availability.

    Science.gov (United States)

    Nijp, Jelmer J; Limpens, Juul; Metselaar, Klaas; Peichl, Matthias; Nilsson, Mats B; van der Zee, Sjoerd E A T M; Berendse, Frank

    2015-06-01

    Boreal peatlands store large amounts of carbon, reflecting their important role in the global carbon cycle. The short-term exchange and the long-term storage of atmospheric carbon dioxide (CO2 ) in these ecosystems are closely associated with the permanently wet surface conditions and are susceptible to drought. Especially, the single most important peat forming plant genus, Sphagnum, depends heavily on surface wetness for its primary production. Changes in rainfall patterns are expected to affect surface wetness, but how this transient rewetting affects net ecosystem exchange of CO2 (NEE) remains unknown. This study explores how the timing and characteristics of rain events during photosynthetic active periods, that is daytime, affect peatland NEE and whether rain event associated changes in environmental conditions modify this response (e.g. water table, radiation, vapour pressure deficit, temperature). We analysed an 11-year time series of half-hourly eddy covariance and meteorological measurements from Degerö Stormyr, a boreal peatland in northern Sweden. Our results show that daytime rain events systematically decreased the sink strength of peatlands for atmospheric CO2 . The decrease was best explained by rain associated reduction in light, rather than by rain characteristics or drought length. An average daytime growing season rain event reduced net ecosystem CO2 uptake by 0.23-0.54 gC m(-2) . On an annual basis, this reduction of net CO2 uptake corresponds to 24% of the annual net CO2 uptake (NEE) of the study site, equivalent to a 4.4% reduction of gross primary production (GPP) during the growing season. We conclude that reduced light availability associated with rain events is more important in explaining the NEE response to rain events than rain characteristics and changes in water availability. This suggests that peatland CO2 uptake is highly sensitive to changes in cloud cover formation and to altered rainfall regimes, a process hitherto largely

  10. Microtopography and methane flux in boreal peatlands, northern Ontario, Canada

    International Nuclear Information System (INIS)

    Bubier, J.; Costello, A.; Moore, T.R.; Roulet, N.T.; Savage, K.

    1993-01-01

    Peatlands act as a major sink of carbon dioxide and a source of methane. Fluxes of methane were measured by a static chamber technique at hummock, hollow, and lawn microtopographic locations in 12 peatland sites near Cochrane, northern Ontario, from May to October 1991. Average fluxes (mg/m 2 /d) were 2.3 at hummocks, 44.4 at hollows, and 15.6 at lawns. Methane flux was negatively correlated with average water table position based on the 36 locations, with hummocks having a smaller flux than hollows or lawns, where the water table depth was <25 cm. Peat samples from a bog hummock and hollow failed to produce methane during anaerobic incubations in the laboratory; samples from a poor fen hollow produced <1.4 μg/g/d. The production decreased with depth but was greater than the rates observed during incubation of samples from an adjacent hummock. Rates of methane consumption during aerobic incubations ranged from 1 to 55 μg/g/d and were greatest in the surface layers and decreased with depth. Differences in methane emissions between hummocks and hollows appear to be controlled primarily by greater methane production rates in hollows compared with hummocks. Of secondary importance are the capacity of the peat profiles to consume methane during its transport to the peat surface and warmer temperatures at the water table beneath hollows compared with hummocks. 29 refs., 4 figs., 2 tabs

  11. Ozone effects on Sphagnum mosses, carbon dioxide exchange and methane emission in boreal peatland microcosms

    International Nuclear Information System (INIS)

    Niemi, Riikka; Holopainen, Toini; Martikainen, Pertti J.; Silvola, Jouko

    2002-01-01

    Microcosms of a boreal peatland originating from an oligotrophic fen in Eastern Finland were fumigated under four ozone concentrations (0, 50, 100 and 150 ppb O 3 ) in laboratory growth chambers during two separate experiments (autumn and summer) for 4 and 6 weeks, respectively. Ozone effects on Sphagnum mosses and the fluxes of carbon dioxide and methane were evaluated. In both experiments, the three Sphagnum species studied showed only a few significant responses to ozone. In the autumn experiment, membrane permeability of S. angustifolium, measured as conductivity and magnesium leakage, was significantly higher under ozone fumigation (P=0.005 and 2 exchange during the 6-week-long summer experiment, but dark ecosystem respiration was transiently increased by ozone concentration of 100 ppb after 14 days of exposure (P<0.05). Fumigation with 100 ppb of ozone, however, more than doubled (P<0.05) methane emission from the peatland monoliths. Our results suggest that increasing tropospheric ozone concentration may cause substantial changes in the carbon gas cycling of boreal peatlands, even though these changes are not closely associated with the changes in Sphagnum vegetation

  12. Aerobic carbon-cycle related microbial communities in boreal peatlands: responses to water-level drawdown

    Energy Technology Data Exchange (ETDEWEB)

    Peltoniemi, K

    2010-07-01

    Boreal peatlands represent a considerable portion of the global carbon (C) pool. Water-level drawdown (WLD) causes peatland drying and induces a vegetation change, which affects the decomposition of soil organic matter and the release of greenhouse gases (CO{sub 2} and CH{sub 4}). The objective of this thesis was to study the microbial communities related to the C cycle and their response to WLD in two boreal peatlands. Both sampling depth and site type had a strong impact on all microbial communities. In general, bacteria dominated the deeper layers of the nutrient-rich fen and the wettest surfaces of the nutrient-poor bog sites, whereas fungi seemed more abundant in the drier surfaces of the bog. WLD clearly affected the microbial communities but the effect was dependent on site type. The fungal and methane-oxidizing bacteria (MOB) community composition changed at all sites but the actinobacterial community response was apparent only in the fen after WLD. Microbial communities became more similar among sites after long-term WLD. Litter quality had a large impact on community composition, whereas the effects of site type and WLD were relatively minor. The decomposition rate of fresh organic matter was influenced slightly by actinobacteria, but not at all by fungi. Field respiration measurements in the northern fen indicated that WLD accelerates the decomposition of soil organic matter. In addition, a correlation between activity and certain fungal sequences indicated that community composition affects the decomposition of older organic matter in deeper peat layers. WLD had a negative impact on CH{sub 4} oxidation, especially in the oligotrophic fen. Fungal sequences were matched to taxa capable of utilizing a broad range of substrates. Most of the actinobacterial sequences could not be matched to characterized taxa in reference databases. This thesis represents the first investigation of microbial communities and their response to WLD among a variety of boreal

  13. Remote Sensing of Light Use Efficiency in a Boreal Forest and Peatland in James Bay, Quebec

    Science.gov (United States)

    Rogers, Cheryl

    The photochemical reflectance index (PRI) is a remotely sensed vegetation index that detects a decrease in spectral reflectance at 531nm associated with xanthophyll cycle activity. PRI has been shown to track light use efficiency (LUE) in a number of plant species. PRI shows great promise in improving our ability to sense photosynthetic fluxes of CO2 remotely. However, it has not been tested in all environments, and its applicability is particularly uncertain for peatland environments dominated by mosses. This research investigates the ability of PRI to track LUE in a boreal forest and peatland, and examines the spectral signal associated with xanthophyll cycle activity in heterogeneous peatland plots. This research also investigates the relationship between PRI and leaf area index (LAI) over space and time in a peatland. We found most plots examined in the peatland site did not exhibit a spectral signal associated with xanthophyll cycle activity when exposed to a transition from dark conditions to full sunlight. This transition should lead to a de-epoxidation of xanthophylls in leaf tissues and a decrease in reflectance at 531nm. Plots that did show the decrease in reflectance at 531nm after this change in light conditions also displayed a decrease in PRI. This indicates that PRI effectively detects the 531nm signal as well as xanthophyll cycle activity and light stress in these plots. However, the variability in the strength of the spectral response to changing light conditions may confound the PRI signal in practice, and make it difficult to interpret results of airborne or satellite data. We also found PRI at the peatland site to be sensitive to and directly correlated with spatial variability in LAI, and negatively correlated with temporal variability in LAI. These characteristics may result in further difficulties applying PRI in peatlands. PRI and LUE were correlated at both the forest and peatland site, however at both sites the PRI signal saturated around

  14. The subcatchment- and catchment-scale hydrology of a boreal headwater peatland complex with sporadic permafrost.

    Science.gov (United States)

    Sonnentag, O.; Helbig, M.; Connon, R.; Hould Gosselin, G.; Ryu, Y.; Karoline, W.; Hanisch, J.; Moore, T. R.; Quinton, W. L.

    2017-12-01

    The permafrost region of the Northern Hemisphere has been experiencing twice the rate of climate warming compared to the rest of the Earth, resulting in the degradation of the cryosphere. A large portion of the high-latitude boreal forests of northwestern Canada grows on low-lying organic-rich lands with relative warm and thin isolated, sporadic and discontinuous permafrost. Along this southern limit of permafrost, increasingly warmer temperatures have caused widespread permafrost thaw leading to land cover changes at unprecedented rates. A prominent change includes wetland expansion at the expense of Picea mariana (black spruce)-dominated forest due to ground surface subsidence caused by the thawing of ice-rich permafrost leading to collapsing peat plateaus. Recent conceptual advances have provided important new insights into high-latitude boreal forest hydrology. However, refined quantitative understanding of the mechanisms behind water storage and movement at subcatchment and catchment scales is needed from a water resources management perspective. Here we combine multi-year daily runoff measurements with spatially explicit estimates of evapotranspiration, modelled with the Breathing Earth System Simulator, to characterize the monthly growing season catchment scale ( 150 km2) hydrological response of a boreal headwater peatland complex with sporadic permafrost in the southern Northwest Territories. The corresponding water budget components at subcatchment scale ( 0.1 km2) were obtained from concurrent cutthroat flume runoff and eddy covariance evapotranspiration measurements. The highly significant linear relationships for runoff (r2=0.64) and evapotranspiration (r2=0.75) between subcatchment and catchment scales suggest that the mineral upland-dominated downstream portion of the catchment acts hydrologically similar to the headwater portion dominated by boreal peatland complexes. Breakpoint analysis in combination with moving window statistics on multi

  15. Microbial production of nitrous oxide and nitric oxide in boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Regina, K.

    1998-12-31

    Soils are an important source of nitrous oxide (N{sub 2}O) and nitric oxide (NO). N{sub 2}O is a greenhouse gas participating in both warming of the climate and the destruction of ozone, and NO is active in tropospheric chemistry. The fluxes and formation mechanisms of these gases in boreal Finnish peatlands were studied by both laboratory and field techniques. Special attention was paid to factors regulating their production, e.g. height of the water table, pH, temperature, nutrient level and nitrification activity. Both N{sub 2}O and NO fluxes were detected in the peatlands, some of which were sources of these trace gases and some sinks. The flux rates of N{sub 2}O ranged from negative values to several milligrammes per square metre per day. Natural peatlands were the lowest sources of N{sub 2}O, often showing negative fluxes, whereas sites drained for forestry some decades ago had markedly higher fluxes. A site drained for agriculture (grassland) was the highest source found. NO fluxes were observed on the two drained sites studied, a forested fen and the same field of grass, but not on a natural fen with a high water table. NO fluxes amounted to 16-30 % of the N{sub 2}O flux rates. The importance of the water table in regulating N{sub 2}0 fluxes was demonstrated in field and laboratory studies. It was shown in the laboratory that even a short lowering of the water table, for 14 weeks at 20 deg C, induced N{sub 2}0 fluxes from the fens that normally acted as sinks or only low sources. Raising the water table in peat monoliths from drained sites reduced the flux of N{sub 2}O. Nutrient-rich peatlands had much higher capacities for N{sub 2}O and NO production than poorer ones. The addition of KNO{sub 3}, NH{sub 4}Cl or urea to minerotrophic peat further increased the fluxes of N{sub 2}O and NO, and also nitrogen mineralisation. There was a clear connection between the fluxes of N{sub 2}0 and NO and nitrification activity measured as the numbers of nitrite

  16. Microbial production of nitrous oxide and nitric oxide in boreal peatlands

    International Nuclear Information System (INIS)

    Regina, K.

    1998-01-01

    Soils are an important source of nitrous oxide (N 2 O) and nitric oxide (NO). N 2 O is a greenhouse gas participating in both warming of the climate and the destruction of ozone, and NO is active in tropospheric chemistry. The fluxes and formation mechanisms of these gases in boreal Finnish peatlands were studied by both laboratory and field techniques. Special attention was paid to factors regulating their production, e.g. height of the water table, pH, temperature, nutrient level and nitrification activity. Both N 2 O and NO fluxes were detected in the peatlands, some of which were sources of these trace gases and some sinks. The flux rates of N 2 O ranged from negative values to several milligrammes per square metre per day. Natural peatlands were the lowest sources of N 2 O, often showing negative fluxes, whereas sites drained for forestry some decades ago had markedly higher fluxes. A site drained for agriculture (grassland) was the highest source found. NO fluxes were observed on the two drained sites studied, a forested fen and the same field of grass, but not on a natural fen with a high water table. NO fluxes amounted to 16-30 % of the N 2 O flux rates. The importance of the water table in regulating N 2 0 fluxes was demonstrated in field and laboratory studies. It was shown in the laboratory that even a short lowering of the water table, for 14 weeks at 20 deg C, induced N 2 0 fluxes from the fens that normally acted as sinks or only low sources. Raising the water table in peat monoliths from drained sites reduced the flux of N 2 O. Nutrient-rich peatlands had much higher capacities for N 2 O and NO production than poorer ones. The addition of KNO 3 , NH 4 Cl or urea to minerotrophic peat further increased the fluxes of N 2 O and NO, and also nitrogen mineralisation. There was a clear connection between the fluxes of N 2 0 and NO and nitrification activity measured as the numbers of nitrite-oxidising bacteria, nitrification potential or in situ net

  17. Microbial production of nitrous oxide and nitric oxide in boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Regina, K

    1999-12-31

    Soils are an important source of nitrous oxide (N{sub 2}O) and nitric oxide (NO). N{sub 2}O is a greenhouse gas participating in both warming of the climate and the destruction of ozone, and NO is active in tropospheric chemistry. The fluxes and formation mechanisms of these gases in boreal Finnish peatlands were studied by both laboratory and field techniques. Special attention was paid to factors regulating their production, e.g. height of the water table, pH, temperature, nutrient level and nitrification activity. Both N{sub 2}O and NO fluxes were detected in the peatlands, some of which were sources of these trace gases and some sinks. The flux rates of N{sub 2}O ranged from negative values to several milligrammes per square metre per day. Natural peatlands were the lowest sources of N{sub 2}O, often showing negative fluxes, whereas sites drained for forestry some decades ago had markedly higher fluxes. A site drained for agriculture (grassland) was the highest source found. NO fluxes were observed on the two drained sites studied, a forested fen and the same field of grass, but not on a natural fen with a high water table. NO fluxes amounted to 16-30 % of the N{sub 2}O flux rates. The importance of the water table in regulating N{sub 2}0 fluxes was demonstrated in field and laboratory studies. It was shown in the laboratory that even a short lowering of the water table, for 14 weeks at 20 deg C, induced N{sub 2}0 fluxes from the fens that normally acted as sinks or only low sources. Raising the water table in peat monoliths from drained sites reduced the flux of N{sub 2}O. Nutrient-rich peatlands had much higher capacities for N{sub 2}O and NO production than poorer ones. The addition of KNO{sub 3}, NH{sub 4}Cl or urea to minerotrophic peat further increased the fluxes of N{sub 2}O and NO, and also nitrogen mineralisation. There was a clear connection between the fluxes of N{sub 2}0 and NO and nitrification activity measured as the numbers of nitrite

  18. CO2 and CH4 fluxes and carbon balance in the atmospheric interaction of boreal peatlands

    International Nuclear Information System (INIS)

    Alm, J.

    1997-01-01

    Release of CO 2 from peat was studied using IR analyzer in a range of boreal peatlands under varying nutrient status and moisture conditions. Root associated CO 2 efflux was separated from the total release by experiments both in the field and in a greenhouse. Emissions of CO 2 and CH 4 (the latter by gas chromatography) were measured during the snow-covered period and their contribution to the annual fluxes of these gases was inspected. Ecosystem exchange of CO 2 under varying irradiation, temperature and moisture conditions was measured at different microsites at two peatland sites with different nutrient ecology. One site represented minerotrophic conditions during a wet growing season and the other site ombrotrophic conditions during an exceptionally dry growing season. Annual carbon balances were compiled for the two sites, and the role of the microsites in the annual carbon balance and CH 4 release was studied. The Holocene history of CO 2 sequestration and CH 4 emission dynamics in a raised mire were simulated using lateral and vertical growth rates derived from radiocarbon ages of peat samples from mire bottom and vertical cores. The model was formulated for a geographic information system (GIS). Artificial or natural lowering of water table increased CO 2 release from peat. A drought lasting from late May to July caused a 90 g C m 2 net loss in the annual C balance of a natural ombrotrophic bog. In drained forested sites the increase in peat CO 2 release could be even 100 %, but the development of the tree layer at least partially compensated for these losses. Wet conditions induced a net accumulation of 67 g C m -2 a -1 in the minerotrophic fen site, while the long term average accumulation rate is estimated to be only 15 g C m -2 a -1 for Finnish fens. Carbon balance in boreal peatlands is thus extremely sensitive to year-to-year climatic variations. Root activity of vascular plants contributed to the total peat CO 2 efflux by 10-40 % as root respiration

  19. Non-methane biogenic volatile organic compound emissions from boreal peatland microcosms under warming and water table drawdown

    DEFF Research Database (Denmark)

    Faubert, P; Tiiva, P; Nakam, TA

    2011-01-01

    assessed the combined effect of warming and water table drawdown on the BVOC emissions from boreal peatland microcosms. We also assessed the treatment effects on the BVOC emissions from the peat soil after the 7-week long experiment. Emissions of isoprene, monoterpenes, sesquiterpenes, other reactive VOCs...

  20. The impact of long-term changes in water table height on carbon cycling in sub-boreal peatlands

    Science.gov (United States)

    Pypker, T. G.; Moore, P. A.; Waddington, J. M.; Hribljan, J. A.; Ballantyne, D.; Chimner, R. A.

    2011-12-01

    Peatlands are a critical component in the global carbon (C) cycle because they have been slowly sequestering atmospheric greenhouse gases as peat since the last glaciation. Today, soil C stocks in peatlands are estimated to represent 224 to 455 Pg, equal to 12-30% of the global soil C pool. At present, peatlands are estimated to sequester 76 Tg C yr-1. The flux of C to and from peatlands is likely to respond to climate change, thereby influencing atmospheric C concentrations. Peatland C budgets are tightly linked to their hydrology, hence, it is critical we understand how changes in hydrology will affect the C budgets of peatlands. The main objective of the project was to determine how long-term changes in water table height affect CO2 and CH4 fluxes from three adjacent peatlands. This study took place in the Seney National Wildlife Refuge (SNWR) in the Upper Peninsula of Michigan. SNWR is home to the largest wetland drainage project in Michigan. In 1912, ditches and dikes were created in an effort to convert approximately 20,000 ha of peatland to agriculture. The ditches and dikes were unsuccessful in creating agricultural land, but they are still in place. The manipulation of water table heights provides an opportunity to research how long-term peat drying or wetting alters C cycling in peatlands. From May to November in 2009, 2010 and 2011, we monitored CO2 fluxes using eddy covariance and chamber techniques in three adjacent peatlands with lowered, relatively unaltered ("control") and raised water table heights. In 2011, we installed CH4 analyzers to continuously monitor CH4 fluxes at the sites with high and relatively unaltered water table heights. The results are compared across sites to determine how changes in water table height might affect C fluxes sub-boreal peatlands.

  1. Peatland use and transport of particulate organic matter in boreal headwater catchments

    Science.gov (United States)

    Marttila, Hannu; Karjalainen, Satu-Maaria; Nieminen, Mika; Kløve, Bjørn

    2014-05-01

    Peatland use can cause increased transport of particulate organic matter (POM) causing deteriorated water quality and especially siltation of stream beds. Even though topic has gained major attention among stakeholders it has received only minor efforts to solve the main sources and properties of transported particles. The development of effective management practices and evaluation of purification efficiency demands understanding of the sources of particulate matter in peat dominated catchments with various land uses and hydrological conditions. The objectives of this study were: (1) to determinate physical properties of POM in headwater brooks affected by different peatland uses, and; (2) to identity the sources of transported material by using sediment fingerprinting methods. For this purpose, two headwater catchments under peat extraction and peatland forestry land uses with 8 sampling points were monitored for 2 years using time integrated suspended sediment samplers. Data was completed by gap samples from 50 other headwater locations with different upstream land uses: pristine, peatland forestry and peat extraction. For the sources analysis, disturbed topsoil, stream bed sediment, banks of ditches and brooks, algae and various vegetation types were identified as the potential sediment sources. Stable isotopes (δ13C, δ15N) and C/N ratio were analyzed to discriminate between the possible sources. Results are further scaled against different land uses, landscape elements and seasonal hydrological conditions in headwaters. This paper presents the preliminary results from a two year study aiming to show various patterns in transport of POM in boreal headwater catchments. Due to strong land-water relationship in headwaters, further information on the properties of particles is needed to assess the downstream impacts of land use.

  2. Effects of warming on N2O fluxes in a boreal peatland of Permafrost region, Northeast China.

    Science.gov (United States)

    Cui, Qian; Song, Changchun; Wang, Xianwei; Shi, Fuxi; Yu, Xueyang; Tan, Wenwen

    2018-03-01

    Climate warming is expected to increasingly influence boreal peatlands and alter their greenhouse gases emissions. However, the effects of warming on N 2 O fluxes and the N 2 O budgets were ignored in boreal peatlands. Therefore, in a boreal peatland of permafrost zone in Northeast China, a simulated warming experiment was conducted to investigate the effects of warming on N 2 O fluxes in Betula. Fruticosa community (B. Fruticosa) and Ledum. palustre community (L. palustre) during the growing seasons from 2013 to 2015. Results showed that warming treatment increased air temperature at 1.5m aboveground and soil temperature at 5cm depth by 0.6°C and 2°C, respectively. The average seasonal N 2 O fluxes ranged from 6.62 to 9.34μgm -2 h -1 in the warming plot and ranged from 0.41 to 4.55μgm -2 h -1 in the control plots. Warming treatment increased N 2 O fluxes by 147% and transformed the boreal peatlands from a N 2 O sink to a source. The primary driving factors for N 2 O fluxes were soil temperature and active layer depth, whereas soil moisture showed a weak correlation with N 2 O fluxes. The results indicated that warming promoted N 2 O fluxes by increasing soil temperature and active layer depth in a boreal peatland of permafrost zone in Northeast China. Moreover, elevated N 2 O fluxes persisted in this region will potentially drive a noncarbon feedback to ongoing climate change. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2017-03-01

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

  4. Proceedings of a symposium on the reclamation and restoration of boreal peatland and forest ecosystems : towards a sustainable future

    Energy Technology Data Exchange (ETDEWEB)

    Bhatti, J. [Natural Resources Canada, Ottawa, ON (Canada); Foote, L.; Moran, S. [Alberta Univ., Edmonton, AB (Canada); Nadeau, L. [Northern Alberta Inst. of Technology, Edmonton, AB (Canada); Rochefort, L. [Laval Univ., Quebec City, PQ (Canada); Short, P. [Canadian Sphagnum Peat Moss Association, St. Albert, AB (Canada); Vitt, D.H. [Southern Illinois Univ., Carbondale, IL (United States); Wieder, K. [Villanova Univ., Villanova, PA (United States)] (comps.)

    2010-07-01

    Disturbances in Canada's boreal forest occur in both upland forests and in peatlands. These disturbances originate from both anthropogenic and natural causes, particularly fire. Techniques for the restoration, as well as the reclamation of peatlands and forests impacted by agriculture, urban development, or oil and gas activities, have made significant advancement over the last decade and these techniques need to be incorporated into the regulation and management of peatland and forest ecosystems. This symposium addressed the issue of how this research is affected by climate change. The sessions were entitled: (1) reclaiming forest and forest soils impacted by oil and gas production, (2) influence of oil sands development on forest communities, (3) understanding the importance of peatland and forest carbon in the twenty-first century, (4) reclaiming wetlands on mined oil sands tailing, (5) disturbance in peatlands and its relevance to minimizing disturbance footprints and informing reclamation efforts, and (6) restoration and management of harvested peatlands. The symposium featured 37 presentations, of which 6 have been catalogued separately for inclusion in this database. refs., tabs., figs.

  5. Wildfire effects on vadose zone hydrology in forested boreal peatland microforms

    Science.gov (United States)

    Thompson, Dan K.; Waddington, James M.

    2013-04-01

    SummaryPeatland vulnerability to wildfire disturbance has been shown to vary as a function of hummock and hollow microforms and vadose zone hydrology, with low-lying hollow microforms most susceptible to deep combustion of peat. To better understand how this microform induced pattern of burning alters vadose water storage, pore-water pressure, and water table relationships, we examined a paired burned and unburned peatland in the boreal plain region of north central Alberta. Water table response to rain events increased significantly after wildfire, resulting in a more variable unsaturated zone thickness that was more responsive to smaller rain events. Water storage losses in the vadose zone occurred primarily at depths greater than 15 cm. Large peat surface water loss occurred in hummock microforms in the early spring due to the presence of unsaturated frozen peat at depth, likely a result of a vapour gradient from the unfrozen peat into the frozen peat underneath. During this period, the loss of water storage in the vadose zone satisfied up to 25% of daily evaporative demand, compared to only 3-5% during ice-free periods. A similar but less severe drying was observed late in summer, with burned hummocks the most vulnerable with high pore-water pressures. The enhanced surface drying observed is a precursor to high pore-water pressure conditions that inhibit Sphagnum regeneration. Our observations point to a paradox where the hummocks, being most resistant to combustion, are themselves most prone to high pore-water pressures following wildfire. The harsher hummock environment may contribute to the observed delay in post-fire Sphagnum regeneration in hummocks compared to hollows.

  6. Transient peat properties in two pond-peatland complexes in the sub-humid Western Boreal Plain, Canada

    Directory of Open Access Journals (Sweden)

    R.M. Petrone

    2008-03-01

    Full Text Available In the Canadian Western Boreal Plain (WBP, wetlands (ponds and peatlands comprise up to 50% of the landscape and represent unique habitat where summer precipitation is often outpaced by evapotranspiration and hillslope groundwater position does not follow topography. In this sub-humid location, groundwater fluxes and stores in riparian peatlands influence pond water levels and root zone moisture sources for forested uplands. To accurately describe the transport and retention of water in peat, it is important to consider peat subsidence. This paper quantifies the amount and effect of seasonal subsidence in a riparian peatland in the Utikuma Lake region in north-central Alberta, Canada. Results demonstrate that the deep and poorly decomposed peat deposits are resistant to compression, and that thick (and persistent ground frost hinders pore collapse (shrinkage above the water table until late summer when the ground has thawed. Even then, subsidence is still limited to the top 50 cm and is not closely related to changes in peatland water table or pond water level. Thus the water balance of these ponds and riparian areas appears to be less sensitive to peat volume changes than it is to the persistence of a substantial frost layer well into the snow-free period.

  7. Climatic sensitivity of hydrology and carbon exchanges in boreal peatland ecosystems, with implications on sustainable management of reed canary grass (Phalaris arundinacea, L.) on cutaway peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Gong Jinnan

    2013-11-01

    The aim of the study was to investigate the effects of climate change on soil hydrology and carbon (C) fluxes in boreal peatland ecosystems, with implications for the feasibility of cultivating reed canary grass (Phalaris arundinacea, L; RCG) as a way to restore the C sink in cutaway peatlands under Finnish conditions. First, hydrological models were developed for pristine peatland ecosystems and the cutaway peatlands under RCG cultivation. Concurrently, the hydrological responses to varying climatic forcing and mire types were investigated for these ecosystems. Thereafter, process-based models for estimating the seasonal and annual C exchanges were developed for the pristine mires and cutaway peatlands. The C models incorporated the hydrological models for corresponding ecosystems. Model simulations based on the climate scenarios (ACCLIM, developed by the Finnish Meteorological Institute, FMI) were further carried out to study the impacts of climate change on the C exchanges in the peatland ecosystems during the 21st century. The simulation showed that the water table (WT) in the pristine Finnish mires would draw down slightly during the 21st century. Such a chance in WT would be related to a decrease in the CO{sub 2} sink but an increase in the CH{sub 4} source at the country scale, as driven mainly by the rising temperature (Ta) and increasing precipitation (P). These changes in CO{sub 2}/ CH{sub 4} fluxes would decrease the total C-greenhouse gas (GHG) sink (CO{sub 2} equilibrium) by 68% at the country scale, and the changes would be more pronounced toward the end of the century. The majority of pristine fens in southern and western Finland and the pristine bogs near the coastal areas would become centurial CO{sub 2} sources under the changing climate. On the other hand, the major distribution of fens in northern Finland would act to increase the CH{sub 4} source at the country scale, whereas the CH{sub 4} emission would tend to decrease with WT in the southern

  8. Gross primary production controls the subsequent winter CO2 exchange in a boreal peatland.

    Science.gov (United States)

    Zhao, Junbin; Peichl, Matthias; Öquist, Mats; Nilsson, Mats B

    2016-12-01

    In high-latitude regions, carbon dioxide (CO 2 ) emissions during the winter represent an important component of the annual ecosystem carbon budget; however, the mechanisms that control the winter CO 2 emissions are currently not well understood. It has been suggested that substrate availability from soil labile carbon pools is a main driver of winter CO 2 emissions. In ecosystems that are dominated by annual herbaceous plants, much of the biomass produced during the summer is likely to contribute to the soil labile carbon pool through litter fall and root senescence in the autumn. Thus, the summer carbon uptake in the ecosystem may have a significant influence on the subsequent winter CO 2 emissions. To test this hypothesis, we conducted a plot-scale shading experiment in a boreal peatland to reduce the gross primary production (GPP) during the growing season. At the growing season peak, vascular plant biomass in the shaded plots was half that in the control plots. During the subsequent winter, the mean CO 2 emission rates were 21% lower in the shaded plots than in the control plots. In addition, long-term (2001-2012) eddy covariance data from the same site showed a strong correlation between the GPP (particularly the late summer and autumn GPP) and the subsequent winter net ecosystem CO 2 exchange (NEE). In contrast, abiotic factors during the winter could not explain the interannual variation in the cumulative winter NEE. Our study demonstrates the presence of a cross-seasonal link between the growing season biotic processes and winter CO 2 emissions, which has important implications for predicting winter CO 2 emission dynamics in response to future climate change. © 2016 John Wiley & Sons Ltd.

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

    Science.gov (United States)

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

    2018-01-01

    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....

  10. Comparative study of elemental mercury flux measurement techniques over a Fennoscandian boreal peatland

    Science.gov (United States)

    Osterwalder, S.; Sommar, J.; Åkerblom, S.; Jocher, G.; Fritsche, J.; Nilsson, M. B.; Bishop, K.; Alewell, C.

    2018-01-01

    Quantitative estimates of the land-atmosphere exchange of gaseous elemental mercury (GEM) are biased by the measurement technique employed, because no standard method or scale in space and time are agreed upon. Here we present concurrent GEM exchange measurements over a boreal peatland using a novel relaxed eddy accumulation (REA) system, a rectangular Teflon® dynamic flux chamber (DFC) and a DFC designed according to aerodynamic considerations (Aero-DFC). During four consecutive days the DFCs were placed alternately on two measurement plots in every cardinal direction around the REA sampling mast. Spatial heterogeneity in peat surface characteristics (0-34 cm) was identified by measuring total mercury in eight peat cores (57 ± 8 ng g-1, average ± SE), vascular plant coverage (32-52%), water table level (4.5-14.1 cm) and dissolved gaseous elemental mercury concentrations (28-51 pg L-1) in the peat water. The GEM fluxes measured by the DFCs showed a distinct diel pattern, but no spatial difference in the average fluxes was detected (ANOVA, α = 0.05). Even though the correlation between the Teflon® DFC and Aero-DFC was significant (r = 0.76, p design is in agreement for cumulative flux estimates with the Aero-DFC, which incorporates the effect of atmospheric turbulence. The comparison was performed over a fetch with spatially rather homogenous GEM flux dynamics under fairly consistent weather conditions, minimizing the effect of weather influence on the data from the three measurement systems. However, in complex biomes with heterogeneous surface characteristics where there can be large spatial variability in GEM gas exchange, the small footprint of chambers (<0.2 m2) makes for large coefficients of variation. Thus many chamber measurement replications are needed to establish a credible biome GEM flux estimate, even for a single point in time. Dynamic flux chambers will, however, be able to resolve systematic differences between small scale features, such as

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

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

    2014-09-01

    Partially decomposed plant and animal remains have been accumulating in organic soils (i.e. >40% C content) for millennia, making them the largest terrestrial carbon store. There is growing concern that, in a warming world, soil biotic processing will accelerate and release greenhouse gases that further exacerbate climate change. However, the magnitude of this response remains uncertain as the constraints are abiotic, biotic and interactive. Here, we examined the influence of resource quality and biological activity on the temperature sensitivity of soil respiration under different soil moisture regimes. Organic soils were sampled from 13 boreal and peatland ecosystems located in the United Kingdom, Ireland, Spain, Finland and Sweden, representing a natural resource quality range of C, N and P. They were incubated at four temperatures (4, 10, 15 and 20 °C) at either 60% or 100% water holding capacity (WHC). Our results showed that chemical and biological properties play an important role in determining soil respiration responses to temperature and moisture changes. High soil C : P and C : N ratios were symptomatic of slow C turnover and long-term C accumulation. In boreal soils, low bacterial to fungal ratios were related to greater temperature sensitivity of respiration, which was amplified in drier conditions. This contrasted with peatland soils which were dominated by bacterial communities and enchytraeid grazing, resulting in a more rapid C turnover under warmer and wetter conditions. The unexpected acceleration of C mineralization under high moisture contents was possibly linked to the primarily role of fermented organic matter, instead of oxygen, in mediating microbial decomposition. We conclude that to improve C model simulations of soil respiration, a better resolution of the interactions occurring between climate, resource quality and the decomposer community will be required. © 2014 John Wiley & Sons Ltd.

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

    Science.gov (United States)

    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

  14. CO{sub 2} and CH{sub 4} fluxes and carbon balance in the atmospheric interaction of boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J.

    1997-12-31

    Release of CO{sub 2} from peat was studied using IR analyzer in a range of boreal peatlands under varying nutrient status and moisture conditions. Root associated CO{sub 2} efflux was separated from the total release by experiments both in the field and in a greenhouse. Emissions of CO{sub 2} and CH{sub 4} (the latter by gas chromatography) were measured during the snow-covered period and their contribution to the annual fluxes of these gases was inspected. Ecosystem exchange of CO{sub 2} under varying irradiation, temperature and moisture conditions was measured at different microsites at two peatland sites with different nutrient ecology. One site represented minerotrophic conditions during a wet growing season and the other site ombrotrophic conditions during an exceptionally dry growing season. Annual carbon balances were compiled for the two sites, and the role of the microsites in the annual carbon balance and CH{sub 4} release was studied. The Holocene history of CO{sub 2} sequestration and CH{sub 4} emission dynamics in a raised mire were simulated using lateral and vertical growth rates derived from radiocarbon ages of peat samples from mire bottom and vertical cores. The model was formulated for a geographic information system (GIS). Artificial or natural lowering of water table increased CO{sub 2} release from peat. A drought lasting from late May to July caused a 90 g C m{sup 2} net loss in the annual C balance of a natural ombrotrophic bog. In drained forested sites the increase in peat CO{sub 2} release could be even 100 %, but the development of the tree layer at least partially compensated for these losses. Wet conditions induced a net accumulation of 67 g C m{sup -2}a{sup -1} in the minerotrophic fen site, while the long term average accumulation rate is estimated to be only 15 g C m{sup -2}a{sup -1} for Finnish fens. Carbon balance in boreal peatlands is thus extremely sensitive to year-to-year climatic variations. Root activity of vascular plants

  15. CO{sub 2} and CH{sub 4} fluxes and carbon balance in the atmospheric interaction of boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J

    1998-12-31

    Release of CO{sub 2} from peat was studied using IR analyzer in a range of boreal peatlands under varying nutrient status and moisture conditions. Root associated CO{sub 2} efflux was separated from the total release by experiments both in the field and in a greenhouse. Emissions of CO{sub 2} and CH{sub 4} (the latter by gas chromatography) were measured during the snow-covered period and their contribution to the annual fluxes of these gases was inspected. Ecosystem exchange of CO{sub 2} under varying irradiation, temperature and moisture conditions was measured at different microsites at two peatland sites with different nutrient ecology. One site represented minerotrophic conditions during a wet growing season and the other site ombrotrophic conditions during an exceptionally dry growing season. Annual carbon balances were compiled for the two sites, and the role of the microsites in the annual carbon balance and CH{sub 4} release was studied. The Holocene history of CO{sub 2} sequestration and CH{sub 4} emission dynamics in a raised mire were simulated using lateral and vertical growth rates derived from radiocarbon ages of peat samples from mire bottom and vertical cores. The model was formulated for a geographic information system (GIS). Artificial or natural lowering of water table increased CO{sub 2} release from peat. A drought lasting from late May to July caused a 90 g C m{sup 2} net loss in the annual C balance of a natural ombrotrophic bog. In drained forested sites the increase in peat CO{sub 2} release could be even 100 %, but the development of the tree layer at least partially compensated for these losses. Wet conditions induced a net accumulation of 67 g C m{sup -2}a{sup -1} in the minerotrophic fen site, while the long term average accumulation rate is estimated to be only 15 g C m{sup -2}a{sup -1} for Finnish fens. Carbon balance in boreal peatlands is thus extremely sensitive to year-to-year climatic variations. Root activity of vascular plants

  16. Stable carbon and nitrogen isotopes in vertical peat profiles of natural and drained boreal peatlands

    Science.gov (United States)

    Nykänen, Hannu; Mpamah, Promise; Rissanen, Antti; Pitkänen, Aki; Turunen, Jukka; Simola, Heikki

    2015-04-01

    Peatlands form a significant carbon pool in the global carbon cycle. Change in peat hydrology, due to global warming is projected to change microbiological processes and peat carbon pool. We tested if bulk stable carbon and nitrogen isotopes serve as indicators of severe long term drying in peatlands drained for forestry. Depth profile analysis of peat, for their carbon and nitrogen content as well as their carbon and nitrogen stable isotopic signatures, were conducted for peatlands in southern and eastern Finland, having ombrotrophic and minerotrophic natural and corresponding drained pairs or separate drained sites. The selection of sites allowed us to compare changes due to different fertility and changes due to long term artificial drying. Drainage lasting over 40 years has led to changes in hydrology, vegetation, nutrient mineralization and respiration. Furthermore, increased nutrient uptake and possible recycling of peat nitrogen and carbon trough vegetation back to the peat surface, also possibly has an effect on the stable isotopic composition of peat carbon and nitrogen. We think that drainage induced changes somehow correspond to those caused by changed hydrology due to climate change. We will present data from these measurements and discuss their implications for carbon and nitrogen flows in peatlands.

  17. Growing season methane emission from a boreal peatland in the continuous permafrost zone of Northeast China: effects of active layer depth and vegetation

    Directory of Open Access Journals (Sweden)

    Y. Miao

    2012-11-01

    Full Text Available Boreal peatlands are significant natural sources of methane and especially vulnerable to abrupt climate change. However, the controlling factors of CH4 emission in boreal peatlands are still unclear. In this study, we investigated CH4 fluxes and abiotic factors (temperature, water table depth, active layer depth, and dissolved CH4 concentrations in pore water during the growing seasons in 2010 and 2011 in both shrub-sphagnum- and sedge-dominated plant communities in the continuous permafrost zone of Northeast China. The objective of our study was to examine the effects of vegetation types and abiotic factors on CH4 fluxes from a boreal peatland. In an Eriophorum-dominated community, mean CH4 emissions were 1.02 and 0.80 mg m−2 h−1 in 2010 and 2011, respectively. CH4 fluxes (0.38 mg m−2 h−1 released from the shrub-mosses-dominated community were lower than that from Eriophorum-dominated community. Moreover, in the Eriophorum-dominated community, CH4 fluxes showed a significant temporal pattern with a peak value in late August in both 2010 and 2011. However, no distinct seasonal variation was observed in the CH4 flux in the shrub-mosses-dominated community. Interestingly, in both Eriophorum- and shrub-sphagnum-dominated communities, CH4 fluxes did not show close correlation with air or soil temperature and water table depth, whereas CH4 emissions correlated well to active layer depth and CH4 concentration in soil pore water, especially in the Eriophorum-dominated community. Our results suggest that CH4 released from the thawed CH4-rich permafrost layer may be a key factor controlling CH4 emissions in boreal peatlands, and highlight that CH4 fluxes vary with vegetation type in boreal peatlands. With

  18. Radiocarbon dating of fluvial organic matter reveals land-use impacts in boreal peatlands

    DEFF Research Database (Denmark)

    Hulatt, Chris J.; Kaartokallio, Hermanni; Oinonen, Markku

    2014-01-01

    This study measured the effects of land use on organic matter released to surface waters in a boreal peat catchment using radiocarbon dating of particulate and dissolved organic carbon (POC and DOC), DOC concentration, stable carbon and nitrogen isotope composition, and optical measurements. Undi...

  19. Litter quality and its response to water level drawdown in boreal peatlands at plant species and community level

    Science.gov (United States)

    Straková, Petra; Anttila, Jani; Spetz, Peter; Kitunen, Veikko; Tapanila, Tarja; Laiho, Raija

    2010-05-01

    There is increasing evidence that changes in the species composition and structure of plant communities induced by global change will have much more impact on plant-mediated carbon cycling than any phenotypic responses. These impacts are largely mediated by shifts in litter quality. There are few documentations of these changes so far, due to the relatively long time scale required for their direct observation. Here, we examine the changes in litter inputs induced by persistent water-level drawdown in boreal peatland sites. Peatlands contain a major proportion of the terrestrial carbon pool, and it is thus important to be able to predict their behaviour and role in the global C cycle under different global change factors. We studied the effects of short-term (ca. 4 years) and long-term (ca. 40 years) persistent water level (WL) drawdown on the quantity and chemical quality of above-ground plant litter inputs at three sites: bog, oligotrophic fen and mesotrophic fen. The parameters used to characterize litter quality included various extractable substances, cellulose, holocellulose, composition of hemicellulose (neutral sugars, uronic acids), lignin, CuO oxidation phenolic products, and concentrations of C, nitrogen (N), phosphorus (P), potassium, magnesium, manganese and calcium. Four different groups of litter were clearly distinct based on their chemical quality: foliar litters, graminoids, mosses and woody litters. The pristine conditions were characterized by Sphagnum moss and graminoid litter. Following short-term WL drawdown, changes in the quality and quantity of litter inputs were small. Following long-term WL drawdown, total litter inputs dramatically increased, due to increased tree litter inputs, and the litter type composition greatly changed. These changes resulted in annual inputs of 1901-2010 kg•ha-1 C, 22-24 kg•ha-1 N, 1.5-2.2 kg•ha-1 P, 967-1235 kg•ha-1 lignin and lignin-like compounds and 254-300 kg•ha-1 water solubles after long-term WL

  20. Partitioning of the net CO2 exchange using an automated chamber system reveals plant phenology as key control of production and respiration fluxes in a boreal peatland.

    Science.gov (United States)

    Järveoja, Järvi; Nilsson, Mats B; Gažovič, Michal; Crill, Patrick M; Peichl, Matthias

    2018-04-30

    The net ecosystem CO 2 exchange (NEE) drives the carbon (C) sink-source strength of northern peatlands. Since NEE represents a balance between various production and respiration fluxes, accurate predictions of its response to global changes require an in depth understanding of these underlying processes. Currently, however, detailed information of the temporal dynamics as well as the separate biotic and abiotic controls of the NEE component fluxes is lacking in peatland ecosystems. In this study, we address this knowledge gap by using an automated chamber system established across natural and trenching-/vegetation removal plots to partition NEE into its production (i.e. gross and net primary production; GPP and NPP) and respiration (i.e. ecosystem, heterotrophic and autotrophic respiration; ER, Rh and Ra) fluxes in a boreal peatland in northern Sweden. Our results showed that daily NEE patterns were driven by GPP while variations in ER were governed by Ra rather than Rh. Moreover, we observed pronounced seasonal shifts in the Ra/Rh and above-/belowground NPP ratios throughout the main phenological phases. Generalized linear model analysis revealed that the greenness index derived from digital images (as a proxy for plant phenology) was the strongest control of NEE, GPP and NPP while explaining considerable fractions also in the variations of ER and Ra. In addition, our data exposed greater temperature sensitivity of NPP compared to Rh resulting in enhanced C sequestration with increasing temperature. Overall, our study suggests that the temporal patterns in NEE and its component fluxes are tightly coupled to vegetation dynamics in boreal peatlands and thus challenges previous studies that commonly identify abiotic factors as key drivers. These findings further emphasize the need for integrating detailed information on plant phenology into process-based models to improve predictions of global change impacts on the peatland C cycle. This article is protected by

  1. Effect of microtopography on isotopic composition of methane in porewater and efflux at a boreal peatland

    Energy Technology Data Exchange (ETDEWEB)

    Dorodnikov, M.; Wilmking, M. [Greifswald Univ. (Georgia). Inst. of Botany and Landscape Ecology; Marushchak, M.; Biasi, C. [Univ. of Eastern Finland, Kuopio (Finland). Dept. of Environmental Science, Bioteknia 2], E-mail: maxim.dorodnikov@uef.fi

    2013-09-01

    The application of stable isotopes is an approach to identify pathways of methanogenesis, methane (CH{sub 4}) oxidation and transport in peatlands. We measured the stable C isotopic characteristics ({delta}C-13) of CH{sub 4} in peat profiles below hummocks, lawns and hollows of a Finnish mire to study the patterns of CH{sub 4} turnover. Porewater CH{sub 4} concentrations ([CH{sub 4}]; at 0.5-2 m) increased with depth below all microforms. Emissions of CH{sub 4} from hummocks were the lowest, and increased with the increasing water-saturated zone, being {approx}10 times higher from hollows. Thus, the microtopography of the peatland did not affect the porewater [CH{sub 4}] in the water-saturated part of the peat profile, but the CH{sub 4} emissions were affected due to differences in the oxidative potential of the microforms. There was a decrease in {delta}C-13-CH{sub 4} with depth below all microforms indicating dominance of CO{sub 2}-reduction over acetate cleavage pathway of methanogenesis at deep peat layers. However, estimated potential portions of transported CH{sub 4} comprised 50%-70% of the {delta}C-13-CH{sub 4} enrichment on microforms at the 0.5-m depth, hereby masking the acetate cleavage pathway of methanogenesis. Stable C composition ({delta}C-13) of CH{sub 4} proved to be a suitable (but not sufficient) tool to differentiate between types of methanogenesis in continuously water-saturated layers below microforms of a peatland. Combined flux-based and multi-isotopic approaches are needed to better understand the CH{sub 4} turnover process. (orig.)

  2. Thermal Acclimation of Photosynthesis and Respiration Differ Across Mature Conifer Species in a Boreal Forest Peatland

    Science.gov (United States)

    Dusenge, M. E.; Stinziano, J. R.; Warren, J.; Ward, E. J.; Wullschleger, S.; Hanson, P. J.; Way, D.

    2017-12-01

    Boreal forests are often assumed to be temperature-limited, and warming is therefore expected to stimulate their carbon uptake. However, much of our information on the ability of boreal conifers to acclimate photosynthesis and respiration to rising temperatures comes from seedlings. We measured net CO2 assimilation rates (A) and dark respiration (R) at 25 °C (A25 and R25) and at prevailing growth temperatures (Ag and Rg) in mature Picea mariana (spruce) and Larix laricina (tamarack) exposed to ambient, +2.25, +4.5, +6.75 and +9 °C warming treatments in open top chambers in the field at the SPRUCE experiment (MN, USA). In spruce, A25 and Ag were similar across plots in May and June. In August, spruce in warmer treatments had higher A25, an effect that was offset by warmer leaf temperatures in the Ag data. In tamarack, A25 was stimulated by warming in both June and August, an effect that was mainly offset by higher leaf temperatures when Ag was assessed in June, while in August, Ag was still slightly higher in the warmest treatments (+6.75 and +9) compared to the ambient plots. In spruce, R25 was enhanced in warm-grown trees in May, but was similar across treatments in June and August, indicating little acclimation of R. Rg slightly increased with warming treatments across the season in spruce. In contrast, R in tamarack thermally acclimated, as R25 decreased with warming. But while this acclimation generated homeostatic Rg in June, Rg in August was still highest in the warmest treatments. Our work suggests that the capacity for thermal acclimation in both photosynthesis and respiration varies among boreal tree species, which may lead to shifts in the performance of these species as the climate warms.

  3. Coupled eco-hydrology and biogeochemistry algorithms enable the simulation of water table depth effects on boreal peatland net CO2 exchange

    Science.gov (United States)

    Mezbahuddin, Mohammad; Grant, Robert F.; Flanagan, Lawrence B.

    2017-12-01

    Water table depth (WTD) effects on net ecosystem CO2 exchange of boreal peatlands are largely mediated by hydrological effects on peat biogeochemistry and the ecophysiology of peatland vegetation. The lack of representation of these effects in carbon models currently limits our predictive capacity for changes in boreal peatland carbon deposits under potential future drier and warmer climates. We examined whether a process-level coupling of a prognostic WTD with (1) oxygen transport, which controls energy yields from microbial and root oxidation-reduction reactions, and (2) vascular and nonvascular plant water relations could explain mechanisms that control variations in net CO2 exchange of a boreal fen under contrasting WTD conditions, i.e., shallow vs. deep WTD. Such coupling of eco-hydrology and biogeochemistry algorithms in a process-based ecosystem model, ecosys, was tested against net ecosystem CO2 exchange measurements in a western Canadian boreal fen peatland over a period of drier-weather-driven gradual WTD drawdown. A May-October WTD drawdown of ˜ 0.25 m from 2004 to 2009 hastened oxygen transport to microbial and root surfaces, enabling greater microbial and root energy yields and peat and litter decomposition, which raised modeled ecosystem respiration (Re) by 0.26 µmol CO2 m-2 s-1 per 0.1 m of WTD drawdown. It also augmented nutrient mineralization, and hence root nutrient availability and uptake, which resulted in improved leaf nutrient (nitrogen) status that facilitated carboxylation and raised modeled vascular gross primary productivity (GPP) and plant growth. The increase in modeled vascular GPP exceeded declines in modeled nonvascular (moss) GPP due to greater shading from increased vascular plant growth and moss drying from near-surface peat desiccation, thereby causing a net increase in modeled growing season GPP by 0.39 µmol CO2 m-2 s-1 per 0.1 m of WTD drawdown. Similar increases in GPP and Re caused no significant WTD effects on modeled

  4. Coupled eco-hydrology and biogeochemistry algorithms enable the simulation of water table depth effects on boreal peatland net CO2 exchange

    Directory of Open Access Journals (Sweden)

    M. Mezbahuddin

    2017-12-01

    Full Text Available Water table depth (WTD effects on net ecosystem CO2 exchange of boreal peatlands are largely mediated by hydrological effects on peat biogeochemistry and the ecophysiology of peatland vegetation. The lack of representation of these effects in carbon models currently limits our predictive capacity for changes in boreal peatland carbon deposits under potential future drier and warmer climates. We examined whether a process-level coupling of a prognostic WTD with (1 oxygen transport, which controls energy yields from microbial and root oxidation–reduction reactions, and (2 vascular and nonvascular plant water relations could explain mechanisms that control variations in net CO2 exchange of a boreal fen under contrasting WTD conditions, i.e., shallow vs. deep WTD. Such coupling of eco-hydrology and biogeochemistry algorithms in a process-based ecosystem model, ecosys, was tested against net ecosystem CO2 exchange measurements in a western Canadian boreal fen peatland over a period of drier-weather-driven gradual WTD drawdown. A May–October WTD drawdown of  ∼  0.25 m from 2004 to 2009 hastened oxygen transport to microbial and root surfaces, enabling greater microbial and root energy yields and peat and litter decomposition, which raised modeled ecosystem respiration (Re by 0.26 µmol CO2 m−2 s−1 per 0.1 m of WTD drawdown. It also augmented nutrient mineralization, and hence root nutrient availability and uptake, which resulted in improved leaf nutrient (nitrogen status that facilitated carboxylation and raised modeled vascular gross primary productivity (GPP and plant growth. The increase in modeled vascular GPP exceeded declines in modeled nonvascular (moss GPP due to greater shading from increased vascular plant growth and moss drying from near-surface peat desiccation, thereby causing a net increase in modeled growing season GPP by 0.39 µmol CO2 m−2 s−1 per 0.1 m of WTD drawdown. Similar increases in

  5. Effect of vegetation removal and water table drawdown on the non-methane biogenic volatile organic compound emissions in boreal peatland microcosms

    Science.gov (United States)

    Faubert, Patrick; Tiiva, Päivi; Rinnan, Åsmund; Räty, Sanna; Holopainen, Jarmo K.; Holopainen, Toini; Rinnan, Riikka

    2010-11-01

    Biogenic volatile organic compound (BVOC) emissions are important in the global atmospheric chemistry and their feedbacks to global warming are uncertain. Global warming is expected to trigger vegetation changes and water table drawdown in boreal peatlands, such changes have only been investigated on isoprene emission but never on other BVOCs. We aimed at distinguishing the BVOCs released from vascular plants, mosses and peat in hummocks (dry microsites) and hollows (wet microsites) of boreal peatland microcosms maintained in growth chambers. We also assessed the effect of water table drawdown (-20 cm) on the BVOC emissions in hollow microcosms. BVOC emissions were measured from peat samples underneath the moss surface after the 7-week-long experiment to investigate whether the potential effects of vegetation and water table drawdown were shown. BVOCs were sampled using a conventional chamber method, collected on adsorbent and analyzed with GC-MS. In hummock microcosms, vascular plants increased the monoterpene emissions compared with the treatment where all above-ground vegetation was removed while no effect was detected on the sesquiterpenes, other reactive VOCs (ORVOCs) and other VOCs. Peat layer from underneath the surface with intact vegetation had the highest sesquiterpene emissions. In hollow microcosms, intact vegetation had the highest sesquiterpene emissions. Water table drawdown decreased monoterpene and other VOC emissions. Specific compounds could be closely associated to the natural/lowered water tables. Peat layer from underneath the surface of hollows with intact vegetation had the highest emissions of monoterpenes, sesquiterpenes and ORVOCs whereas water table drawdown decreased those emissions. The results suggest that global warming would change the BVOC emission mixtures from boreal peatlands following changes in vegetation composition and water table drawdown.

  6. Emissions and dynamics of N{sub 2}O in a buffer wetland receiving water flows from a forested peatland

    Energy Technology Data Exchange (ETDEWEB)

    Saari, P. [Centre for Economic Development, Jyvaskyla (Finland). Transport and the Environment], Email: paivi.saari@ely-keskus.fi; Saarnio, S. [Univ. of Eastern Finland, Joensuu (Finland). Finnish Environment Inst., Dept. of Biology; Heinonen, J.; Alm, J. [Finnish Forest Research Inst., Joensuu (Finland)

    2013-06-01

    Forestry operations can cause disturbances in nutrient cycling. Protection of watercourses by trapping the leached solids and nutrients in sedimentation ponds and buffer zones may create a new greenhouse gases (GHG) source. We measured in situ nitrous oxide (N{sub 2}O) fluxes in different parts of a spruce swamp buffer zone, N{sub 2}O emissions from intact peat columns after fertilization with different ammonium nitrate (NH{sub 4}NO{sub 3}) levels, and the rate and volume of in vivo N{sub 2}O accumulation. N{sub 2}O-producing micro-organisms existed throughout the buffer zone. The rate of N{sub 2}O formation was highest at depths close to the prevailing water table within the buffer zone. Groundwater level and the vicinity of bypass water flows at the soil surface regulated the spatial and temporal variation in the rate of N{sub 2}O efflux in the field. Nitrogen (N) addition rapidly increased in vivo N{sub 2}O release. Microbial activity in the laboratory incubations under optimal conditions was high, but the in situ N{sub 2}O efflux in the field was low. The actual leaching of mineral N from forestry areas was low and the inorganic N concentration in the buffer zone inflow was no higher than is typical for humic brooks or lakes in Finland. The low N{sub 2}O fluxes indicated that forestry operations in the catchment did not result in significant N enrichment of the buffer zone. This study does not support the postulate that peatland buffer zones may become significant sources of N{sub 2}O. (orig.)

  7. Climate-vegetation-fire interactions and their impact on long-term carbon dynamics in a boreal peatland landscape in northern Manitoba, Canada

    Science.gov (United States)

    Camill, Philip; Barry, Ann; Williams, Evie; Andreassi, Christian; Limmer, Jacob; Solick, Donald

    2009-12-01

    Climate warming may increase the size and frequency of fires in the boreal biome, possibly causing greater carbon release that amplifies warming. However, in peatlands, vegetation change may also control long-term fire and carbon accumulation, confounding simple relationships between climate, fire, and carbon accumulation. Using 17 peat cores dating to 8000 cal years B.P. from northern Manitoba, Canada, we addressed the following questions: (1) Do past climate changes correlate with shifts in peatland vegetation? (2) What is the relationship between peatland vegetation and fire severity? (3) What is the mean return interval for boreal peat fires, and how does it change across fires of different severities? (4) How does fire severity affect carbon accumulation rates? (5) Do fire and long-term carbon accumulation change directly in response to climate or indirectly though climate-driven changes in vegetation? We measured carbon accumulation rates, fire severity, and return intervals using macroscopic charcoal and changes in vegetation using macrofossils. Climate and vegetation changes covaried, with shifts from wetter fen to drier, forested bog communities during the Holocene Thermal Maximum (HTM). Fires became more severe following the shift to forested bogs, with fire severity peaking after 4000 cal years B.P. rather than during the HTM. Rising fire severity, in turn, was correlated with a significant decrease in carbon accumulation from ˜6000 to 2000 cal years B.P. The Medieval Warm Period and Little Ice Age affected vegetation composition and permafrost, further impacting fire and carbon accumulation. Our results indicate that long-term changes in fire and carbon dynamics are mediated by climate-driven changes in vegetation.

  8. Minor effects of long-term ozone exposure on boreal peatland species Eriophorum vaginatum and Sphagnum papillosum

    DEFF Research Database (Denmark)

    Mörsky, SK; Haapala, JK; Rinnan, Riikka

    2011-01-01

    The effects of long-term ozone fumigation on two common peatland plant species, a sedge Eriophorum vaginatum L. and a moss Sphagnum papillosum Lindb., were studied applying peatland microcosms. The peat cores with intact vegetation were cored from an oligotrophic pine fen and partially embedded...

  9. A synthesis of the impacts of ditch network maintenance on the quantity and quality of runoff from drained boreal peatland forests.

    Science.gov (United States)

    Nieminen, Mika; Palviainen, Marjo; Sarkkola, Sakari; Laurén, Ari; Marttila, Hannu; Finér, Leena

    2017-10-29

    Drained peatlands are an important source of forest biomass in boreal regions and ditch network maintenance (DNM) operations may be needed to restore the drainage functions of ditches. By reviewing the available literature, as well as utilizing an existing hydrological model and analyzing the characteristics of eroded sediments, we assessed the impacts of DNM on runoff and exports of suspended solids (SS), dissolved organic carbon (DOC), nitrogen (N), and phosphorus (P). In general, DNM had minor impact on runoff and dissolved N and P, and it decreased rather than increased DOC exports. To increase the understanding of the hydrochemical impacts of DNM, future research should focus on the characteristics of SS and particulate nutrient exports. A major gap in knowledge is also the very limited regional representativeness of the available studies. High erosion risk in the ditches reaching the mineral soil below peat should be acknowledged when planning mitigation measures.

  10. Increase in carbon accumulation in a boreal peatland following a period of wetter climate and long-term decrease in nitrogen deposition.

    Science.gov (United States)

    Utstøl-Klein, Simon; Halvorsen, Rune; Ohlson, Mikael

    2015-06-01

    Rates of peat growth and carbon (C) accumulation in a Sphagnum-dominated boreal peatland in south-east Norway were compared over two time periods each 17 yr long, that is, an earlier period from 1978 to 1995 and a recent period from 1995 to 2012. Our research was based on 109 peat cores. By using exactly the same study area and sampling protocols to obtain data for the two time periods, we were able to obtain a clear picture of the spatio-temporal patterns of peat accumulation. We show that peat growth and C accumulation were significantly higher in the recent than in the earlier time period. Interestingly, nitrogen (N) deposition was lower in the recent than in the earlier time period, while precipitation increased in the recent time period. Temperatures did not show any consistent trends over the time periods. Although our data do not allow assessment of the relative importance of declining N deposition vs increasing precipitation as drivers of peat accumulation, our results suggest that peatland C sequestration is not significantly inhibited by N pollution at current precipitation and N deposition levels. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  11. Gross photosynthesis explains the ‘artificial bias’ of methane fluxes by static chamber (opaque versus transparent) at the hummocks in a boreal peatland

    International Nuclear Information System (INIS)

    Luan, Junwei; Wu, Jianghua

    2014-01-01

    The closed chamber technique has been widely employed to detect methane emissions, despite little being known about whether the absence or presence of light will impact the flux estimation. Here, we employed a laser greenhouse gas analyzer with an opaque—transparent chamber pair to measure the methane emission rate in a boreal peatland complex. Microtopography (i.e., hummocks and hollows) in natural and drained peatlands, and plant communities (i.e., grasses and shrubs) in a pasture converted from natural peatlands, were considered to cover the local heterogeneity. Our results indicated that opaque chambers (0.58–0.78 g CH 4 m −2 during the growing season) measured a significantly higher (∼2–3 times) methane emission at the hummocks than transparent chambers (∼0.24 g CH 4 m −2 ); however, a similar phenomenon was not found at the hollows or at other measurement plots. Gross photosynthesis explained 44%–47% of the temporal variation of the ‘artificial bias’ (the difference in methane flux obtained by the opaque versus transparent chambers) at the hummocks. Additionally, both water table depth and surface soil moisture significantly explained spatial variations of methane emissions. Our study suggests that microtopography has a significant influence on the artificial bias in methane emission estimation and the artificial properties of a chamber (transparency/opacity) method can be vitally important in some cases (i.e., hummocks), and negligible in others (i.e., hollows). The observed connection between the photosynthesis process and the ‘artificial bias’ of closed chambers (opaque versus transparent) can be used to improve methane flux modeling. Separate parameterization schemes are needed for methane transportation under the presence or absence of light. (paper)

  12. Long-term enhanced winter soil frost alters growing season CO2 fluxes through its impact on vegetation development in a boreal peatland.

    Science.gov (United States)

    Zhao, Junbin; Peichl, Matthias; Nilsson, Mats B

    2017-08-01

    At high latitudes, winter climate change alters snow cover and, consequently, may cause a sustained change in soil frost dynamics. Altered winter soil conditions could influence the ecosystem exchange of carbon dioxide (CO 2 ) and, in turn, provide feedbacks to ongoing climate change. To investigate the mechanisms that modify the peatland CO 2 exchange in response to altered winter soil frost, we conducted a snow exclusion experiment to enhance winter soil frost and to evaluate its short-term (1-3 years) and long-term (11 years) effects on CO 2 fluxes during subsequent growing seasons in a boreal peatland. In the first 3 years after initiating the treatment, no significant effects were observed on either gross primary production (GPP) or ecosystem respiration (ER). However, after 11 years, the temperature sensitivity of ER was reduced in the treatment plots relative to the control, resulting in an overall lower ER in the former. Furthermore, early growing season GPP was also lower in the treatment plots than in the controls during periods with photosynthetic photon flux density (PPFD) ≥800 μmol m -2  s -1 , corresponding to lower sedge leaf biomass in the treatment plots during the same period. During the peak growing season, a higher GPP was observed in the treatment plots under the low light condition (i.e. PPFD 400 μmol m -2  s -1 ) compared to the control. As Sphagnum moss maximizes photosynthesis at low light levels, this GPP difference between the plots may have been due to greater moss photosynthesis, as indicated by greater moss biomass production, in the treatment plots relative to the controls. Our study highlights the different responses to enhanced winter soil frost among plant functional types which regulate CO 2 fluxes, suggesting that winter climate change could considerably alter the growing season CO 2 exchange in boreal peatlands through its effect on vegetation development. © 2017 John Wiley & Sons Ltd.

  13. Benthic macroinvertebrates and the use of stable isotopes (δ13C and δ15N) in the impact assessment of peatland use on boreal stream ecosystems

    Science.gov (United States)

    Nieminen, Mika L.; Daza Secco, Emmanuela; Nykänen, Hannu; Meissner, Kristian

    2013-04-01

    Stable isotope analysis (SIA) can provide insights into carbon flow dynamics and trophic positions of consumers in food webs. SIA is used in this study, where we assess the possible changes in the basal resources of Finnish boreal stream ecosystems and differences in the impact of two forms of peatland use, forestry and peat mining. About 30% of the total land area of Finland is classified as peatland, of which about 55% has been drained for forestry and about 0.6% is in peat production. Unlike forestry, peat production is regionally less scattered and can thus have measurable local impacts although the total area of peat production is small. Three watersheds were used as study areas. Within each watershed, one stream drains a subcatchment affected only by peat mining, whereas the other stream flows through a subcatchment affected by forestry. The two subcatchment streams merge to form a single stream flowing into a lake. Studied watersheds were subject to no other forms of land use. In addition to the impacted sites, we used two pristine natural mire and two natural forest catchments as controls. We analysed the stable isotopes of carbon (δ13C) and nitrogen (δ15N) from benthic macroinvertebrates, stream bank soil, stream sediment, and dissolved organic carbon (DOC) in stream water. Samples for stable isotope analyses were collected in the summer of 2011 and samples for invertebrate community analyses in the autumn of 2011. Upon sampling we measured several physical parameters at each sampling site. In addition, stream water samples collected in summer and autumn 2012 were analysed for CH4 and CO2 gas concentrations and autumn gas samples also for their δ13C values. Our initial SIA results of invertebrates suggest some degree of discrimination between different sources of OM and possible effects on feeding habits, presumably due to the quality of the basal resources. We will explore this result further by examining not only taxonomical structure, but also the

  14. Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water level regimes

    Science.gov (United States)

    Straková, P.; Niemi, R. M.; Freeman, C.; Peltoniemi, K.; Toberman, H.; Heiskanen, I.; Fritze, H.; Laiho, R.

    2011-02-01

    Peatlands are carbon (C) storage ecosystems sustained by a high water level (WL). High WL creates anoxic conditions that suppress the activity of aerobic decomposers and provide conditions for peat accumulation. Peatland function can be dramatically affected by WL drawdown caused by land-use and/or climate change. Aerobic decomposers are directly affected by WL drawdown through environmental factors such as increased oxygenation and nutrient availability. Additionally, they are indirectly affected via changes in plant community composition and litter quality. We studied the relative importance of direct and indirect effects of WL drawdown on aerobic decomposer activity in plant litter. We did this by profiling 11 extracellular enzymes involved in the mineralization of organic C, nitrogen, phosphorus and sulphur. Our study sites represented a three-stage chronosequence from pristine (undrained) to short-term (years) and long-term (decades) WL drawdown conditions under two nutrient regimes. The litter types included reflected the prevalent vegetation, i.e., Sphagnum mosses, graminoids, shrubs and trees. WL drawdown had a direct and positive effect on microbial activity. Enzyme allocation shifted towards C acquisition, which caused an increase in the rate of decomposition. However, litter type overruled the direct effects of WL drawdown and was the main factor shaping microbial activity patterns. Our results imply that changes in plant community composition in response to persistent WL drawdown will strongly affect the C dynamics of peatlands.

  15. Methane oxidation associated to submerged brown-mosses buffers methane emissions from Siberian polygonal peatlands

    Science.gov (United States)

    Liebner, Susanne; Zeyer, Josef; Knoblauch, Christian

    2010-05-01

    Circumpolar peatlands store roughly 18 % of the globally stored carbon in soils [based on 1, 2]. Also, northern wetlands and tundra are a net source of methane (CH4), an effective greenhouse gas (GHG), with an estimated annual CH4 release of 7.2% [3] or 8.1% [4] of the global total CH4 emission. Although it is definite that Arctic tundra significantly contributes to the global methane emissions in general, regional variations in GHG fluxes are enormous. CH4 fluxes of polygonal tundra within the Siberian Lena Delta, for example, were reported to be low [5, 6], particularly at open water polygonal ponds and small lakes [7] which make up around 10 % of the delta's surface. Low methane emissions from polygonal ponds oppose that Arctic permafrost thaw ponds are generally known to emit large amounts of CH4 [8]. Combining tools of biogeochemistry and molecular microbiology, we identified sinks of CH4 in polygonal ponds from the Lena Delta that were not considered so far in GHG studies from Arctic wetlands. Pore water CH4 profiling in polygonal ponds on Samoylov, a small island in the central part of the Lena Delta, revealed a pronounced zone of CH4 oxidation near the vegetation surface in submerged layers of brown-mosses. Here, potential CH4 oxidation was an order of magnitude higher than in non-submerged mosses and in adjacent bulk soil. We could additionally show that this moss associated methane oxidation (MAMO) is hampered when exposure of light is prevented. Shading of plots with submerged Scorpidium scorpioides inhibited MAMO leading to higher CH4 concentrations and an increase in CH4 fluxes by a factor of ~13. Compared to non-submerged mosses, the submerged mosses also showed significantly lower δ13C values indicating that they use carbon dioxide derived from methane oxidation for photosynthesis. Applying stable isotope probing of DNA, type II methanotrophs were identified to be responsible for the oxidation of CH4 in the submerged Scorpidium scorpioides. Our

  16. Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water table regimes

    Directory of Open Access Journals (Sweden)

    P. Straková

    2011-09-01

    Full Text Available Peatlands are carbon (C storage ecosystems sustained by a high water table (WT. High WT creates anoxic conditions that suppress the activity of aerobic decomposers and provide conditions for peat accumulation. Peatland function can be dramatically affected by WT drawdown caused by climate and/or land-use change. Aerobic decomposers are directly affected by WT drawdown through environmental factors such as increased oxygenation and nutrient availability. Additionally, they are indirectly affected via changes in plant community composition and litter quality. We studied the relative importance of direct and indirect effects of WT drawdown on aerobic decomposer activity in plant litter at two stages of decomposition (incubated in the field for 1 or 2 years. We did this by profiling 11 extracellular enzymes involved in the mineralization of organic C, nitrogen (N, phosphorus (P and sulphur. Our study sites represented a three-stage chronosequence from pristine to short-term (years and long-term (decades WT drawdown conditions under two nutrient regimes (bog and fen. The litter types included reflected the prevalent vegetation: Sphagnum mosses, graminoids, shrubs and trees.

    Litter type was the main factor shaping microbial activity patterns and explained about 30 % of the variation in enzyme activities and activity allocation. Overall, enzyme activities were higher in vascular plant litters compared to Sphagnum litters, and the allocation of enzyme activities towards C or nutrient acquisition was related to the initial litter quality (chemical composition. Direct effects of WT regime, site nutrient regime and litter decomposition stage (length of incubation period summed to only about 40 % of the litter type effect. WT regime alone explained about 5 % of the variation in enzyme activities and activity allocation. Generally, enzyme activity increased following the long-term WT drawdown and the activity allocation turned from P

  17. Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water table regimes

    Science.gov (United States)

    Straková, P.; Niemi, R. M.; Freeman, C.; Peltoniemi, K.; Toberman, H.; Heiskanen, I.; Fritze, H.; Laiho, R.

    2011-09-01

    Peatlands are carbon (C) storage ecosystems sustained by a high water table (WT). High WT creates anoxic conditions that suppress the activity of aerobic decomposers and provide conditions for peat accumulation. Peatland function can be dramatically affected by WT drawdown caused by climate and/or land-use change. Aerobic decomposers are directly affected by WT drawdown through environmental factors such as increased oxygenation and nutrient availability. Additionally, they are indirectly affected via changes in plant community composition and litter quality. We studied the relative importance of direct and indirect effects of WT drawdown on aerobic decomposer activity in plant litter at two stages of decomposition (incubated in the field for 1 or 2 years). We did this by profiling 11 extracellular enzymes involved in the mineralization of organic C, nitrogen (N), phosphorus (P) and sulphur. Our study sites represented a three-stage chronosequence from pristine to short-term (years) and long-term (decades) WT drawdown conditions under two nutrient regimes (bog and fen). The litter types included reflected the prevalent vegetation: Sphagnum mosses, graminoids, shrubs and trees. Litter type was the main factor shaping microbial activity patterns and explained about 30 % of the variation in enzyme activities and activity allocation. Overall, enzyme activities were higher in vascular plant litters compared to Sphagnum litters, and the allocation of enzyme activities towards C or nutrient acquisition was related to the initial litter quality (chemical composition). Direct effects of WT regime, site nutrient regime and litter decomposition stage (length of incubation period) summed to only about 40 % of the litter type effect. WT regime alone explained about 5 % of the variation in enzyme activities and activity allocation. Generally, enzyme activity increased following the long-term WT drawdown and the activity allocation turned from P and N acquisition towards C

  18. Peatland Woody Plant Growth Responses to Warming and Elevated CO2 in a Southern-boreal Raised Bog Ecosystem

    Science.gov (United States)

    Phillips, J. R.; Hanson, P. J.; Warren, J.; Ward, E. J.; Brice, D. J.; Graham, J.

    2017-12-01

    Spruce and Peatland Responses Under Changing Environments (SPRUCE) is an in situ warming by elevated CO2 manipulation located in a high-carbon, spruce peatland in northern Minnesota. Warming treatments combined a 12-m diameter open topped chamber with internally recirculating warm air and soil deep heating to simulate a broad range of future warming treatments. Deep below ground soil warming rates are 0, +2.25, +4.5, +6.75, and +9 °C. Deep belowground warming was initiated in June 2014 followed by air warming in August 2015. In June 2016, elevated CO2 atmospheres (eCO2 at + 500 ppm) were added to half of the warming treatments in a regression design. Our objective was to track long-term vegetation responses to warming and eCO2. Annual tree growth is based on winter measurement of circumference of all Picea mariana and Larix laricina trees within each 113 m2 plot, automated dendrometers, terrestrial LIDAR scanning of tree heights and canopy volumes, and destructive allometry. Annual shrub growth is measured in late summer by destructive clipping in two 0.25 m2 sub-plots and separation of the current year tissues. During the first year of warming, tree basal area growth was reduced for Picea, but not Larix trees. Growth responses for the woody shrub vegetation remains highly variable with a trend towards increasing growth with warming. Elevated CO2 enhancements of growth are not yet evident in the data. Second-year results will also be reported. Long-term hypotheses for increased woody plant growth under warming include potential enhancements driven by increased nutrient availability from warming induced decomposition of surface peats.

  19. Microbial community stratification linked to utilization of carbohydrates and phosphorus limitation in a boreal peatland at Marcell Experimental Forest, Minnesota, USA.

    Science.gov (United States)

    Lin, Xueju; Tfaily, Malak M; Steinweg, J Megan; Chanton, Patrick; Esson, Kaitlin; Yang, Zamin K; Chanton, Jeffrey P; Cooper, William; Schadt, Christopher W; Kostka, Joel E

    2014-06-01

    This study investigated the abundance, distribution, and composition of microbial communities at the watershed scale in a boreal peatland within the Marcell Experimental Forest (MEF), Minnesota, USA. Through a close coupling of next-generation sequencing, biogeochemistry, and advanced analytical chemistry, a biogeochemical hot spot was revealed in the mesotelm (30- to 50-cm depth) as a pronounced shift in microbial community composition in parallel with elevated peat decomposition. The relative abundance of Acidobacteria and the Syntrophobacteraceae, including known hydrocarbon-utilizing genera, was positively correlated with carbohydrate and organic acid content, showing a maximum in the mesotelm. The abundance of Archaea (primarily crenarchaeal groups 1.1c and 1.3) increased with depth, reaching up to 60% of total small-subunit (SSU) rRNA gene sequences in the deep peat below the 75-cm depth. 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 predominated in the deeper catotelm. RNA-derived pyrosequence libraries corroborated DNA sequence data to indicate that the above-mentioned microbial groups are metabolically active in the mid-depth zone. Fungi showed a maximum in rRNA gene abundance above the 30-cm depth, which comprised only an average of 0.1% of total bacterial and archaeal rRNA gene abundance, indicating prokaryotic dominance. Ratios of C to P enzyme activities approached 0.5 at the acrotelm and catotelm, indicating phosphorus limitation. In contrast, P limitation pressure appeared to be relieved in the mesotelm, likely due to P solubilization by microbial production of organic acids and C-P lyases. Based on path analysis and the modeling of community spatial turnover, we hypothesize that P limitation outweighs N limitation at

  20. Ecophysiology at SPRUCE: Impacts of whole ecosystem warming and elevated CO2 on leaf-level photosynthesis and respiration of two ericaceous shrubs in a boreal peatland

    Science.gov (United States)

    Ward, E. J.; Dusenge, M. E.; Warren, J.; Murphy, B. K.; Way, D.; King, A. W.; McLennan, D.; Montgomery, R.; Stefanski, A.; Reich, P. B.; Cruz Aguilar, M.; Wullschleger, S.; Bermudez Villanueva, R.; Hanson, P. J.

    2017-12-01

    The Spruce and Peatland Responses Under Changing Environments (SPRUCE) project is a large-scale, long-term experiment investigating the effects of warming and elevated CO2 on an ombrotrophic bog in Minnesota, USA. SPRUCE uses 10 large (12.8-m diameter) enclosures to increase air and soil temperatures to a range of targets (+0 °C, +2.25 °C, +4.5 °C, +6.75 °C, +9 °C) under both ambient and elevated (+500 ppm) CO2 concentrations. Whole-ecosystem-warming treatments began in August 2015 and elevated CO2 treatments began in June 2016. This talk will address the photosynthetic and respiratory responses of vascular plants to the treatments as measured with a variety of in-situ and ex-situ measurements conducted throughout the 2016 and 2017 growing seasons. We will focus on the responses of two dominant ericaceous shrubs (Rhododendron groenlandicum and Chamaedaphne calyculata), which account for more 80% of the understory biomass of this open-canopy forest. Such physiological changes are not only leading indicators of changes in plant growth and community structure, but are crucial to understanding carbon cycling of raised bogs and representing boreal peatlands in global dynamic vegetation models. Pre-treatment data collected at this site indicate that the physiologically active season typically begins in late May and extends into the fall until freezing nighttime temperatures are consistently reached, typically in October. Post-treatment measurements made during seasonal transitions indicate a longer active physiological season in warmer treatments. Results from 2016 measurements show some degree of thermal acclimation of photosynthesis in R. groenlandicum and of respiration in both species in the early growing season, but not late season. Late season measurements show a down-regulation of photosynthesis in both shrub species grown under elevated CO2. Taken as a whole, these results indicate complex interactions between phenological changes and treatment effects on

  1. Chemical characteristics of dissolved organic matter (DOM) in relation to heavy metal concentrations in soil water from boreal peatlands after clear-cut harvesting

    Science.gov (United States)

    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

  2. Brown carbon aerosols from burning of boreal peatlands: microphysical properties, emission factors, and implications for direct radiative forcing

    Directory of Open Access Journals (Sweden)

    R. K. Chakrabarty

    2016-03-01

    Full Text Available The surface air warming over the Arctic has been almost twice as much as the global average in recent decades. In this region, unprecedented amounts of smoldering peat fires have been identified as a major emission source of climate-warming agents. While much is known about greenhouse gas emissions from these fires, there is a knowledge gap on the nature of particulate emissions and their potential role in atmospheric warming. Here, we show that aerosols emitted from burning of Alaskan and Siberian peatlands are predominantly brown carbon (BrC – a class of visible light-absorbing organic carbon (OC – with a negligible amount of black carbon content. The mean fuel-based emission factors for OC aerosols ranged from 3.8 to 16.6 g kg−1. Their mass absorption efficiencies were in the range of 0.2–0.8 m2 g−1 at 405 nm (violet and dropped sharply to 0.03–0.07 m2 g−1 at 532 nm (green, characterized by a mean Ångström exponent of  ≈  9. Electron microscopy images of the particles revealed their morphologies to be either single sphere or agglomerated “tar balls”. The shortwave top-of-atmosphere aerosol radiative forcing per unit optical depth under clear-sky conditions was estimated as a function of surface albedo. Only over bright surfaces with albedo greater than 0.6, such as snow cover and low-level clouds, the emitted aerosols could result in a net warming (positive forcing of the atmosphere.

  3. Decadal vegetation changes in a northern peatland, greenhouse gas fluxes and net radiative forcing

    DEFF Research Database (Denmark)

    Johansson, Torbjörn; Malmer, Nils; Crill, Patrick M

    2006-01-01

    SUB-ARCTIC MIRE; CLIMATE-CHANGE; BOREAL PEATLANDS; METHANE EMISSIONS; VASCULAR PLANTS; CARBON-DIOXIDE; PERMAFROST THAW; CO2 EXCHANGE; WATER-TABLE......SUB-ARCTIC MIRE; CLIMATE-CHANGE; BOREAL PEATLANDS; METHANE EMISSIONS; VASCULAR PLANTS; CARBON-DIOXIDE; PERMAFROST THAW; CO2 EXCHANGE; WATER-TABLE...

  4. Vegetative changes in boreal peatlands along salinity gradients resulting from produced water spills : implications for the environmental assessment and remediation of upstream oil and gas sites

    Energy Technology Data Exchange (ETDEWEB)

    Bright, D.; Harris, C.; Meier, M. [AECOM Canada Ltd., Ottawa, ON (Canada)

    2010-07-01

    In the province of Alberta, there are approximately 8,000 registered oil effluent and produced pipelines that have significant potential for ruptures and spills due to the highly corrosive nature of the emulsions and produced water they transport. Most releases occur in or adjacent to northern boreal wetlands. The first objective in spill response involves assessment and remediation for residuals, which involves handling and disposal of large volumes of salinized water. This presentation reported on a study that addressed the issues regarding the ecological features of semi-terrestrial and semi-aquatic components of boreal wetland environments as a basis for environmental protection at salt release sites. The fate of salt ions in such environments was examined along with the implications for secondary succession and ecological restoration. The study also examined the reasonable threshold concentration of salt ions in soils or water beyond which there is an inhibition to wetlands plants and bryophyte secondary succession; the reasonable threshold concentration of salt ions in water beyond which there may be adverse effects on invertebrates, vertebrates and other non-plant taxa; and species sensitivity distributions for floral and faunal assemblages found in boreal wetland habitats. The presentation summarized the 3 phases of a project that examined pipeline ruptures at 9 sites. Field methods and site sampling summaries were presented. It was difficult to locate study sites with residual salt contamination in surface media at concentrations above effects threshold for many species. It was concluded that the departures between surface and subsurface salinity indicates a smaller potential for effects on site vegetation. tabs., figs.

  5. Vegetative changes in boreal peatlands along salinity gradients resulting from produced water spills : implications for the environmental assessment and remediation of upstream oil and gas sites

    International Nuclear Information System (INIS)

    Bright, D.; Harris, C.; Meier, M.

    2010-01-01

    In the province of Alberta, there are approximately 8,000 registered oil effluent and produced pipelines that have significant potential for ruptures and spills due to the highly corrosive nature of the emulsions and produced water they transport. Most releases occur in or adjacent to northern boreal wetlands. The first objective in spill response involves assessment and remediation for residuals, which involves handling and disposal of large volumes of salinized water. This presentation reported on a study that addressed the issues regarding the ecological features of semi-terrestrial and semi-aquatic components of boreal wetland environments as a basis for environmental protection at salt release sites. The fate of salt ions in such environments was examined along with the implications for secondary succession and ecological restoration. The study also examined the reasonable threshold concentration of salt ions in soils or water beyond which there is an inhibition to wetlands plants and bryophyte secondary succession; the reasonable threshold concentration of salt ions in water beyond which there may be adverse effects on invertebrates, vertebrates and other non-plant taxa; and species sensitivity distributions for floral and faunal assemblages found in boreal wetland habitats. The presentation summarized the 3 phases of a project that examined pipeline ruptures at 9 sites. Field methods and site sampling summaries were presented. It was difficult to locate study sites with residual salt contamination in surface media at concentrations above effects threshold for many species. It was concluded that the departures between surface and subsurface salinity indicates a smaller potential for effects on site vegetation. tabs., figs.

  6. The impact of climate change on Canadian peatlands

    International Nuclear Information System (INIS)

    Tarnocai, C.

    2009-01-01

    This paper discussed the sensitivity of Canadian peatlands to climate change, with particular emphasis on the carbon dynamics, water regime changes and the contribution of peatlands to atmospheric greenhouse gases. Peatlands cover 12 per cent of the Canadian landscape, with most occurring in the boreal and subarctic regions. In total, the peatlands contain nearly 147 Gt of soil organic carbon, or about 56 per cent of the organic carbon stored in all Canadian soils. A peatland sensitivity model that was used to determine the effect of climate warming on peatlands revealed that about 60 per cent of the boreal and subarctic regions and 56 per cent of the organic carbon mass in all Canadian peatlands will be severely to extremely severely affected by climate change, and at an accelerated rate than ever before. Climate change predictions suggest that the greatest effects of climate warming on Canadian peatlands will occur in areas with perennially frozen peat. The major concern in these areas is that the melting of the frozen peat will result in waterlogged conditions. In contrast, drying of non-permafrost peatlands will result in a higher frequency and extent of wildfires. As a result of these changes, large amounts of carbon in the forms of carbon dioxide (CO 2 ) and methane (CH 4 ) will be released into the atmosphere from these peatlands, which will further accelerate climate warming. 43 refs., 2 tabs., 7 figs.

  7. Meeting the challenge of mapping peatlands with remotely sensed data

    Directory of Open Access Journals (Sweden)

    O. N. Krankina

    2008-12-01

    Full Text Available Boreal peatlands play a major role in carbon and water cycling and other global environmental processes but understanding this role is constrained by inconsistent representation of peatlands on, or omission from, many global land cover maps. The comparison of several widely used global and continental-scale databases on peatland distribution with a detailed map for the St. Petersburg region of Russia showed significant under-reporting of peatland area, or even total omission. Analysis of the spatial agreement and disagreement with the detailed regional map indicated that the error of comission (overestimation was significantly lower than the error of omission (underestimation which means, that overall, peatlands were correctly classified as such in coarse resolution datasets but a large proportion (74–99% was overlooked. The coarse map resolution alone caused significant omission of peatlands in the study region. In comparison to categorical maps, continuous field mapping approach utilizing MODIS sensor data showed potential for a greatly improved representation of peatlands on coarse resolution maps. Analysis of spectral signatures of peatlands with different types of surface vegetation suggested that improved mapping of boreal peatlands on categorical maps is feasible. The lower reflectance of treeless peatlands in the near- and shortwave-infrared parts of the electromagnetic spectrum is consistent with the spectral signature of sphagnum mosses. However, when trees are present, the canopy architecture appears to be more important in defining the overall spectral reflectance of peatlands. A research focus on developing remote sensing methods for boreal peatlands is needed for adequate characterization of their global distribution.

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

    Science.gov (United States)

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

    2015-01-01

    A series of severe droughts during the course of a long-term, atmospheric sulfate-deposition experiment in a boreal peatland in northern Minnesota created a unique opportunity to study how methylmercury (MeHg) production responds to drying and rewetting events in peatlands under variable levels of sulfate loading. Peat oxidation during extended dry periods mobilized...

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

    Science.gov (United States)

    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...

  10. Initial Response of the Nitrogen Cycle to Soil Warming and Elevated CO2 in Northern Minnesota Peatlands

    Science.gov (United States)

    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...

  11. Bioavailability and radiocarbon age of fluvial dissolved organic matter (DOM) from a northern peatland-dominated catchment: effect of land-use change

    DEFF Research Database (Denmark)

    Hulatt, C.J.; Kaartokallio, H.; Asmala, E.

    2014-01-01

    . Bacterial growth efficiency ranged from 0.11 to 0.26 between areas of different land use, and these relatively low values reflect the humic-rich DOM released from boreal peatland. Despite the range of land-use types studied, including intensive peatland excavation areas, there was no detectable relationship...

  12. Ditch network maintenance in peat-dominated boreal forests: Review and analysis of water quality management options.

    Science.gov (United States)

    Nieminen, Mika; Piirainen, Sirpa; Sikström, Ulf; Löfgren, Stefan; Marttila, Hannu; Sarkkola, Sakari; Laurén, Ari; Finér, Leena

    2018-03-27

    The objective of this study was to evaluate the potential of different water management options to mitigate sediment and nutrient exports from ditch network maintenance (DNM) areas in boreal peatland forests. Available literature was reviewed, past data reanalyzed, effects of drainage intensity modeled, and major research gaps identified. The results indicate that excess downstream loads may be difficult to prevent. Water protection structures constructed to capture eroded matter are either inefficient (sedimentation ponds) or difficult to apply (wetland buffers). It may be more efficient to decrease erosion, either by limiting peak water velocity (dam structures) or by adjusting ditch depth and spacing to enable satisfactory drainage without exposing the mineral soil below peat. Future research should be directed towards the effects of ditch breaks and adjusted ditch depth and spacing in managing water quality in DNM areas.

  13. Sulfate reduction in freshwater peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Oequist, M.

    1996-12-31

    This text consist of two parts: Part A is a literature review on microbial sulfate reduction with emphasis on freshwater peatlands, and part B presents the results from a study of the relative importance of sulfate reduction and methane formation for the anaerobic decomposition in a boreal peatland. The relative importance of sulfate reduction and methane production for the anaerobic decomposition was studied in a small raised bog situated in the boreal zone of southern Sweden. Depth distribution of sulfate reduction- and methane production rates were measured in peat sampled from three sites (A, B, and C) forming an minerotrophic-ombrotrophic gradient. SO{sub 4}{sup 2-} concentrations in the three profiles were of equal magnitude and ranged from 50 to 150 {mu}M. In contrast, rates of sulfate reduction were vastly different: Maximum rates in the three profiles were obtained at a depth of ca. 20 cm below the water table. In A it was 8 {mu}M h{sup -1} while in B and C they were 1 and 0.05 {mu}M h{sup -1}, respectively. Methane production rates, however, were more uniform across the three nutrient regimes. Maximum rates in A (ca. 1.5 {mu}g d{sup -1} g{sup -1}) were found 10 cm below the water table, in B (ca. 1.0 {mu}g d{sup -1} g{sup -1}) in the vicinity of the water table, and in C (0.75 {mu}g d{sup -1} g{sup -1}) 20 cm below the water table. In all profiles both sulfate reduction and methane production rates were negligible above the water table. The areal estimates of methane production for the profiles were 22.4, 9.0 and 6.4 mmol m{sup -2} d{sup -1}, while the estimates for sulfate reduction were 26.4, 2.5, and 0.1 mmol m{sup -2} d{sup -1}, respectively. The calculated turnover times at the sites were 1.2, 14.2, and 198.7 days, respectively. The study shows that sulfate reducing bacteria are important for the anaerobic degradation in the studied peatland, especially in the minerotrophic sites, while methanogenic bacteria dominate in ombrotrophic sites Examination

  14. Sulfate reduction in freshwater peatlands

    International Nuclear Information System (INIS)

    Oequist, M.

    1996-01-01

    This text consist of two parts: Part A is a literature review on microbial sulfate reduction with emphasis on freshwater peatlands, and part B presents the results from a study of the relative importance of sulfate reduction and methane formation for the anaerobic decomposition in a boreal peatland. The relative importance of sulfate reduction and methane production for the anaerobic decomposition was studied in a small raised bog situated in the boreal zone of southern Sweden. Depth distribution of sulfate reduction- and methane production rates were measured in peat sampled from three sites (A, B, and C) forming an minerotrophic-ombrotrophic gradient. SO 4 2- concentrations in the three profiles were of equal magnitude and ranged from 50 to 150 μM. In contrast, rates of sulfate reduction were vastly different: Maximum rates in the three profiles were obtained at a depth of ca. 20 cm below the water table. In A it was 8 μM h -1 while in B and C they were 1 and 0.05 μM h -1 , respectively. Methane production rates, however, were more uniform across the three nutrient regimes. Maximum rates in A (ca. 1.5 μg d -1 g -1 ) were found 10 cm below the water table, in B (ca. 1.0 μg d -1 g -1 ) in the vicinity of the water table, and in C (0.75 μg d -1 g -1 ) 20 cm below the water table. In all profiles both sulfate reduction and methane production rates were negligible above the water table. The areal estimates of methane production for the profiles were 22.4, 9.0 and 6.4 mmol m -2 d -1 , while the estimates for sulfate reduction were 26.4, 2.5, and 0.1 mmol m -2 d -1 , respectively. The calculated turnover times at the sites were 1.2, 14.2, and 198.7 days, respectively. The study shows that sulfate reducing bacteria are important for the anaerobic degradation in the studied peatland, especially in the minerotrophic sites, while methanogenic bacteria dominate in ombrotrophic sites Examination paper. 67 refs, 6 figs, 3 tabs

  15. The stoichiometry of peatlands

    Science.gov (United States)

    Moore, Tim

    2017-04-01

    Stoichiometric principles have been developed and successfully applied to freshwater and marine ecosystems, which are characterized by short-lived, structurally simple organisms, simple food webs and an environment which allows rapid movement of water and elements. The application has been less successful in peatlands, and other terrestrial ecosystems: not surprising given their long-lived, structurally complex organisms, slow rates of organic matter decomposition, complex food webs and low hydraulic conductivities slowing water and element movement. I examine some aspects of what we know about stoichiometry in peatlands, especially involving nutrients such as C, N, P, K, Ca and Mg. I follow the cascade of stoichiometry from peatland plants through litter and into decomposing peat, drawing upon data from the Mer Bleue peatland and peatlands in Ontario. There are consistent patterns in stoichiometries, such as C:N, N:P and C:P across diverse peatlands, whereas patterns involving K, Ca and Mg show greater variability. Most of the changes in stoichiometry occur in the early stages of decomposition, from Von Post values 1 through 4. Peatlands are affected by disturbances, such as elevated atmospheric deposition of N and P, and I look at how these changes affect stoichiometric relationships. Finally, I present data on the changes in the stoichiometry of C, H and O, from plants through peat to coal beds. I conclude that while ecological stoichiometry in peatlands is not as 'simple' as in aquatic ecosystems, it offers contributions to our understanding of how peatlands function and respond to disturbance.

  16. Boreal forests

    International Nuclear Information System (INIS)

    Essen, P.A.; Ericson, L.; Ehnstroem, B.; Sjoeberg, K.

    1997-01-01

    We review patterns and processes important for biodiversity in the Fennoscandian boreal forest, describe man's past and present impact and outline a strategy for conservation. Natural disturbances, particularly forest fire and gap formation, create much of the structural and functional diversity in forest ecosystems. Several boreal plants and animals are adapted to fire regimes. In contrast, many organisms (epiphytic lichens, fungi, invertebrates) require stable conditions with long continuity in canopy cover. The highly mechanized and efficient Fennoscandian forest industry has developed during the last century. The result is that most natural forest has been lost and that several hundreds of species, mainly cryptograms and invertebrates, are threatened. The forestry is now in a transition from exploitation to sustainable production and has recently incorporated some measures to protect the environment. Programmes for maintaining biodiversity in the boreal forest should include at least three parts. First, the system of forest reserves must be significantly improved through protection of large representative ecosystems and key biotopes that host threatened species. Second, we must restore ecosystem properties that have been lost or altered. Natural disturbance regimes must be allowed to operate or be imitated, for example by artificial fire management. Stand-level management should particularly increase the amount of coarse woody debris, the number of old deciduous trees and large, old conifers, by using partial cutting. Third, natural variation should also be mimicked at the landscape level, for example, by reducing fragmentation and increasing links between landscape elements. Long-term experiments are required to evaluate the success of different management methods in maintaining biodiversity in the boreal forest. (au) 260 refs

  17. Possible responses of northern peatlands to climate change in the zone of discontinuous permafrost, Manitoba, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Bubier, J L [New Hampshire Univ., Durham, NH (United States). Inst. for the Study of Earth, Oceans, and Space; Moore, T R [McGill Univ., Montreal (Canada). Geography Dept.

    1997-12-31

    More than half of the world`s peatlands occur in the boreal zone (45 - 60 deg C N. lat), a region which global climate models predict will experience large changes in temperature and precipitation with increasing atmospheric CO{sub 2} concentrations. The northern part of the boreal zone is characterised by discontinuous permafrost, an area that is particularly sensitive to climate change with the possible degradation and thawing of frozen peat. Peatlands are large sources of atmospheric methane (CH{sub 4}), an important greenhouse gas. Yet few measurements of methane have been conducted in discontinuous permafrost environments. As part of the Boreal Ecosystem-Atmosphere Study (BOREAS), CH{sub 4} flux was measured in a diverse peatland complex (bogs, fens, peat plateaus, and collapse scars), representing the complete range of temperature, moisture, and plant community gradients found in northern peatlands. The measurement period May to September 1994 was one of the warmest and driest seasons on record, which provided an opportunity to observe the short-term responses of different parts of the peatland ecosystem to a warmer and drier climate as an analog to predicted climate change in the region. (5 refs.)

  18. Possible responses of northern peatlands to climate change in the zone of discontinuous permafrost, Manitoba, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Bubier, J.L. [New Hampshire Univ., Durham, NH (United States). Inst. for the Study of Earth, Oceans, and Space; Moore, T.R. [McGill Univ., Montreal (Canada). Geography Dept.

    1996-12-31

    More than half of the world`s peatlands occur in the boreal zone (45 - 60 deg C N. lat), a region which global climate models predict will experience large changes in temperature and precipitation with increasing atmospheric CO{sub 2} concentrations. The northern part of the boreal zone is characterised by discontinuous permafrost, an area that is particularly sensitive to climate change with the possible degradation and thawing of frozen peat. Peatlands are large sources of atmospheric methane (CH{sub 4}), an important greenhouse gas. Yet few measurements of methane have been conducted in discontinuous permafrost environments. As part of the Boreal Ecosystem-Atmosphere Study (BOREAS), CH{sub 4} flux was measured in a diverse peatland complex (bogs, fens, peat plateaus, and collapse scars), representing the complete range of temperature, moisture, and plant community gradients found in northern peatlands. The measurement period May to September 1994 was one of the warmest and driest seasons on record, which provided an opportunity to observe the short-term responses of different parts of the peatland ecosystem to a warmer and drier climate as an analog to predicted climate change in the region. (5 refs.)

  19. N cycling in SPRUCE (Spruce Peatlands Response Under Climatic and Environmental Changes)

    Science.gov (United States)

    Peatlands located in boreal regions make up a third of global wetland area and are expected to have the highest temperature increases in response to climate change. As climate warms, we expect peat decomposition may accelerate, altering the cycling of nitrogen. Alterations in th...

  20. Built-up resilience to climate change in peatlands

    Science.gov (United States)

    Wang, H.; Tian, J.; Ho, M.; Flanagan, N. E.; Vilgalys, R.; Richardson, C. J.

    2017-12-01

    Peatlands have stored about 30% of global soil carbon over millennia. Most studies suggest that climate change effects, like drought and warming, may decrease C sequestration and increase C loss in peatlands, thus resulting in a positive feedback on climate change. However, the long-term feedback between plant-microbe mediated carbon processes and climate change still remains highly uncertain. Here, we conducted a series of field and lab experiments in southern shrub and northern Sphagnum peatlands to document how previously unrecognized mechanisms regulate the buildup of anti-microbial phenolics, which protects stored carbon directly by reducing phenol oxidase activity during short-term drought, and indirectly through a shift from low-phenolics Sphagnum/herbs to high-phenolics shrubs after long-term moderate drought. We further showed a symbiosis of slow-growing decomposers concomitant with a shift of high-phenolic plants, which increased peat resistance to disturbance. Our results indicate that shrub expansion induced by climate change in boreal peatlands may be a long-term self-adaptive mechanism not only increasing carbon sequestration, but also potentially protecting soil carbon. Therefore, peatlands are highly resilient ecosystems in which the symbiotic adaption of both plants and microbes, triggered by persistent climate change, likely can acclimate to the stressors and maintain their carbon sequestration function and processes.

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

    Science.gov (United States)

    Benscoter, B.; Turetsky, M. R.

    2011-12-01

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

  2. Spatially explicit simulation of peatland hydrology and carbon dioxide exchange

    International Nuclear Information System (INIS)

    Sonnentag, O.

    2008-01-01

    A recent version of the Boreal Ecosystem Productivity Simulator (BEPS) was extended and modified to include northern peatlands. This thesis evaluated the BEPS-TerrainLab using observations made at the Mer Bleue bog located near Ottawa, Ontario, and the Sandhill fen located near Prince Albert, Saskatchewan. The code was revised to represent the multi-layer canopy and processes related to energy, water vapour and carbon dioxide fluxes through remotely-sensed leaf area index (LAI) maps. A quick and reliable method was also developed to determine shrub LAI with the LAI-2000 plant canopy analyzer. A large number of LAI data was collected at the Mer Bleue bog for the development of a new remote sensing-based methodology using multiple end member spectral unmixing to allow for separate tree and shrub LAI mapping in ombrotrophic peatlands. The methodology was also adapted for use in minerotrophic peatlands and their surrounding landscapes. These LAI maps within the BEPS-TerrainLab represented the tree and shrub layers of the Mer Bleue bog and the tree and shrub/sedge layers of the Sandhill fen. The study examined the influence of mesoscale topography (Mer Bleue bog) and macro- and mesoscale topography (Sandhill fen) on wetness, evapotranspiration, and gross primary productivity during the snow-free period of 2004. The results suggested that a peatland type-specific differentiation of macro- and mesoscale topographic effects on hydrology should be included in future peatland ecosystem modelling efforts in order to allow for a more realistic simulation of the soil water balance in peatlands and to reduce uncertainties in carbon dioxide and methane annual fluxes from wetlands

  3. Spatially explicit simulation of peatland hydrology and carbon dioxide exchange

    Energy Technology Data Exchange (ETDEWEB)

    Sonnentag, O.

    2008-08-01

    A recent version of the Boreal Ecosystem Productivity Simulator (BEPS) was extended and modified to include northern peatlands. This thesis evaluated the BEPS-TerrainLab using observations made at the Mer Bleue bog located near Ottawa, Ontario, and the Sandhill fen located near Prince Albert, Saskatchewan. The code was revised to represent the multi-layer canopy and processes related to energy, water vapour and carbon dioxide fluxes through remotely-sensed leaf area index (LAI) maps. A quick and reliable method was also developed to determine shrub LAI with the LAI-2000 plant canopy analyzer. A large number of LAI data was collected at the Mer Bleue bog for the development of a new remote sensing-based methodology using multiple end member spectral unmixing to allow for separate tree and shrub LAI mapping in ombrotrophic peatlands. The methodology was also adapted for use in minerotrophic peatlands and their surrounding landscapes. These LAI maps within the BEPS-TerrainLab represented the tree and shrub layers of the Mer Bleue bog and the tree and shrub/sedge layers of the Sandhill fen. The study examined the influence of mesoscale topography (Mer Bleue bog) and macro- and mesoscale topography (Sandhill fen) on wetness, evapotranspiration, and gross primary productivity during the snow-free period of 2004. The results suggested that a peatland type-specific differentiation of macro- and mesoscale topographic effects on hydrology should be included in future peatland ecosystem modelling efforts in order to allow for a more realistic simulation of the soil water balance in peatlands and to reduce uncertainties in carbon dioxide and methane annual fluxes from wetlands.

  4. Restoration of harvested peatlands

    International Nuclear Information System (INIS)

    Saarmets, Tiit

    1999-01-01

    A short analysis of the main topics of the IPS Symposium Peatland Restoration and Reclamation, Duluth, Minnesota, USA, 1998 is given. It has been single-mindedly recommended in Estonia so far that harvested peatland surfaces should be levelled and outflows shut. But following these recommendations will lead to an unfounded formation of marshy areas with a very low growth of plants. The reclamation of harvested peatlands for agricultural purposes is expensive and there is no commercial need for agricultural land in today's Estonia now. In the author's opinion the foreflows and intermediate ditches should be left open which would favour the growth of the brushwood to grow later into the forest of commercial value. (author)

  5. Tropical Peatland Geomorphology and Hydrology

    Science.gov (United States)

    Cobb, A.; Harvey, C. F.

    2017-12-01

    Tropical peatlands cover many low-lying areas in the tropics. In tropical peatlands, a feedback between hydrology, landscape morphology, and carbon storage causes waterlogged organic matter to accumulate into gently mounded land forms called peat domes over thousands of years. Peat domes have a stable morphology in which peat production is balanced by loss and net precipitation is balanced by lateral flow, creating a link between peatland morphology, rainfall patterns and drainage networks. We show how landscape morphology can be used to make inferences about hydrologic processes in tropical peatlands. In particular, we show that approaches using simple storage-discharge relationships for catchments are especially well suited to tropical peatlands, allowing river forecasting based on peatland morphology in catchments with tropical peatland subcatchments.

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

    Science.gov (United States)

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

    2013-01-01

    It is important to understand the fate of carbon in boreal peatland soils in response to climate change because a substantial change in release of this carbon as CO2 and CH4 could influence the climate system. The goal of this research was to synthesize the results of a field water table manipulation experiment conducted in...

  7. New insights on ecosystem mercury cycling revealed by stable isotopes of mercury in water flowing from a headwater peatland catchment

    Science.gov (United States)

    Glenn E. Woerndle; Martin Tsz-Ki Tsui; Stephen D. Sebestyen; Joel D. Blum; Xiangping Nie; Randall K. Kolka

    2018-01-01

    Stable isotope compositions of mercury (Hg) were measured in the outlet stream and in soil cores at different landscape positions in a 9.7-ha boreal upland-peatland catchment. An acidic permanganate/persulfate digestion procedure was validated for water samples with high dissolved organic matter (DOM) concentrations through Hg spike addition analysis. We report a...

  8. Global warming considerations in northern Boreal forest ecosystems

    International Nuclear Information System (INIS)

    Slaughter, C.W.

    1993-01-01

    The northern boreal forests of circumpolar lands are of special significance to questions of global climate change. Throughout its range, these forests are characterized by a relatively few tree species, although they may exhibit great spatial heterogeneity. Their ecosystems are simpler than temperate systems, and ecosystem processes are strongly affected by interactions between water, the landscape, and the biota. Northern boreal forest vegetation patterns are strongly influenced by forest fires, and distribution of forest generally coincides with occurrence of permafrost. Boreal forest landscapes are extremely sensitive to thermal disruption; global warming may result in lasting thermal and physical degradation of soils, altered rates and patterns of vegetation succession, and damage to engineered structures. A change in fire severity and frequency is also a significant concern. The total carbon pool of boreal forests and their associated peatlands is significant on a global scale; this carbon may amount to 10-20% of the global carbon pool. A change in latitudinal or elevational treeline has been suggested as a probable consequence of global warming. More subtle aspects of boreal forest ecosystems which may be affected by global warming include the depth of the active soil layer, the hydrologic cycle, and biological attributes of boreal stream systems. 48 refs., 2 figs

  9. Effect of inundation, oxygen and temperature on carbon mineralization in boreal ecosystems.

    Science.gov (United States)

    Kim, Youngil; Ullah, Sami; Roulet, Nigel T; Moore, Tim R

    2015-04-01

    The inundation of boreal forests and peatlands through the construction of hydroelectric reservoirs can increase carbon dioxide (CO2) and methane (CH4) emission. To establish controls on emission rates, we incubated samples of forest and peat soils, spruce litter, forest litter and peatland litter collected from boreal ecosystems in northern Quebec for 16 weeks and measured CO2 and CH4 production rates under flooded or non-flooded conditions and varying oxygen concentration and temperature. CO2 production under flooded conditions was less than under non-flooded conditions (5-71 vs. 5-85 mg Cg(-1) C), but CH4 production under flooded conditions was larger than under non-flooded conditions (1-8158 vs. 0-86 μg Cg(-1) C). The average CO2 and CH4 production rate factor for flooded:non-flooded conditions was 0.76 and 1.32, respectively. Under flooded conditions, high oxygen concentrations increased CO2 production in peat soils but decreased CH4 production in forest and peat soils and spruce litter. Warmer temperatures (from 4 to 22°C) raised both CO2 production in peat soils and peatland litter, and CH4 production in peat soils and spruce litter. This study shows that the direction and/or strength of CO2 and CH4 fluxes change once boreal forests and peatlands are inundated. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2006-12-01

    A number of field carbon flux measurements, paleoecological records, and model simulations have acknowledged the importance of northern peatlands in terrestrial carbon cycling and methane emissions. An important parameter in peatlands that influences both net primary productivity, the net gain of carbon through photosynthesis, and decomposition under aerobic and anaerobic conditions, is the position of the water table. Biological and physical processes involved in peatland carbon dynamics and their hydrological controls operate at different spatial scales. The highly variable hydraulic characteristics of the peat profile and the overall shape of the peat body as defined by its surface topography at the mesoscale (104 m2) are of major importance for peatland water table dynamics. Common types of peatlands include bogs with a slightly domed centre. As a result of the convex profile, their water supply is restricted to atmospheric inputs, and water is mainly shed by shallow subsurface flow. From a modelling perspective the influence of mesotopographic controls on peatland hydrology and thus carbon balance requires that process-oriented models that examine the links between peatland hydrology, ecosystem functioning, and climate must incorporate some form of lateral subsurface flow consideration. Most hydrological and ecological modelling studies in complex terrain explicitly account for the topographic controls on lateral subsurface flow through digital elevation models. However, modelling studies in peatlands often employ simple empirical parameterizations of lateral subsurface flow, neglecting the influence of peatlands low relief mesoscale topography. Our objective is to explicitly simulate the mesotopographic controls on peatland hydrology and carbon fluxes using the Boreal Ecosystem Productivity Simulator (BEPS) adapted to northern peatlands. BEPS is a process-oriented ecosystem model in a remote sensing framework that takes into account peatlands multi

  11. Hydrogeological controls on spatial patterns of groundwater discharge in peatlands

    Directory of Open Access Journals (Sweden)

    D. K. Hare

    2017-11-01

    Full Text Available Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns

  12. Hydrogeological controls on spatial patterns of groundwater discharge in peatlands

    Science.gov (United States)

    Hare, Danielle K.; Boutt, David F.; Clement, William P.; Hatch, Christine E.; Davenport, Glorianna; Hackman, Alex

    2017-11-01

    Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns may allow resource

  13. The peatland map of Europe

    NARCIS (Netherlands)

    Tanneberger, Franziska; Tegetmeyer, C.; Busse, S.; Barthelmes, A.; Shumka, S.; Mariné, A.M.; Jenderedjian, K.; Steiner, G.M.; Essl, F.; Etzold, J.; Mendes, C.; Kozulin, A.; Frankard, P.; Milanović,; Ganeva, A.; Apostolova, I.; Alegro, A.; Delipetrou, P.; Navrátilová, J.; Risager, M.; Leivits, A.; Fosaa, A.M.; Tuominen, S.; Muller, F.; Bakuradze, T.; Sommer, M.; Christanis, K.; Szurdoki, E.; Oskarsson, H.; Brink, S.H.; Connolly, J.; Bragazza, L.; Martinelli, G.; Aleksāns, O.; Priede, A.; Sungaila, D.; Melovski, L.; Belous, T.; Saveljić, D.; Vries, De F.; Moen, A.; Dembek, W.; Mateus, J.; Hanganu, J.; Sirin, A.; Markina, A.; Napreenko, M.; Lazarević, P.; Stanová, V.Š.; Skoberne, P.; Pérez, P.H.; Pontevedra-Pombal, X.; Lonnstad, J.; Küchler, M.; Wüst-Galley, C.; Kirca, S.; Mykytiuk, O.; Lindsay, R.; Joosten, H.

    2017-01-01

    Based on the ‘European Mires Book’ of the International Mire Conservation Group (IMCG), this article provides a composite map of national datasets as the first comprehensive peatland map for the whole of Europe. We also present estimates of the extent of peatlands and mires in each European country

  14. Managing erosion, sediment transport and water quality in drained peatland catchments

    Energy Technology Data Exchange (ETDEWEB)

    Marttila, H.

    2010-07-01

    Peatland drainage changes catchment conditions and increases the transport of suspended solids (SS) and nutrients. New knowledge and management methods are needed to reduce SS loading from these areas. This thesis examines sediment delivery and erosion processes in a number of peatland drainage areas and catchments in order to determine the effects of drainage on sediment and erosion dynamics and mechanics. Results from studies performed in peat mining, peatland forestry and disturbed headwater catchments in Finland are presented and potential sediment load management methods are discussed for drainage areas and headwater brooks. Particular attention is devoted to erosion of organic peat, sediment transport and methods to reduce the impacts of peatland drainage in boreal headwaters. This thesis consists of six articles. The first and second papers focus on the erosion and sediment transport processes at peat harvesting and peatland forestry drainage networks. The results indicate that in-channel processes are important in drained peatland, since the drainage network often constitutes temporary inter-storm storage for eroding and transporting material. Sediment properties determine the bed sediment erosion sensitivity, as fluffy organic peat sediment consolidates over time. As flashiness and peak runoff control sediment entrainment and transport from drained peatland areas, water quality management should include peak runoff management. The third, fourth and fifth papers studies use and application of peak runoff control (PRC) method to the peat harvesting and peatland forestry conditions for water protection. Results indicate that effective water quality management in drained peatland areas can be achieved using this method. Installation of the PRC structures is a useful and cost-effective way of storing storm runoff waters temporarily in the ditch system and providing a retention time for eroded sediment to settle to the ditch bed and drainage network. The main

  15. Organic matter accumulation and community change at the peatland-upland interface: inferences from 14C and 210Pb dated profiles

    Science.gov (United States)

    Ilka E. Bauer; Jagtar S. Bhatti; Christopher Swanston; R. Kelman Wieder; Caroline M. Perston

    2009-01-01

    Peatland-margin habitats with organic matter accumulation of 40-150 cm make up a significant but poorly quantified portion of Canada's boreal forest region. Spanning the transition between non-wetland forest and fen proper, these ecosystems represent a zone of complex environmental and vegetation change, yet little is known about their ecological function or...

  16. Abstracts of the 15. annual workshop of the Peatland Ecology Research Group (PERG) : peatland event 2008

    International Nuclear Information System (INIS)

    2008-01-01

    The Peatland Ecology Research Group (PERG) deals with the integrated sustainable management of Canadian peatlands, with projects involving the development of ecological restoration of peatland ecosystems after peat mining; reclamation of abandoned peatlands; hydrology, geochemistry, microbiology of natural, harvested and restored peatlands; peatland conservation strategies; and Sphagnum moss ecology and productivity. The Group has established a method for the re-establishing vegetation on mined peatlands. Research by PERG has initiated the development of global peatland conservation strategies. This workshop featured 35 presentations, of which 9 have been catalogued separately for inclusion in this database

  17. Heterotrophic soil respiration in forestry-drained peatlands

    International Nuclear Information System (INIS)

    Minkkinen, K.; Shurpali, N. J.; Alm, J.; Penttilae, T.

    2007-01-01

    Heterotrophic soil respiration (CO 2 efflux from the decomposition of peat and root litter) in three forestry-drained peatlands with different site types and with a large climatic gradient from the hemi-boreal (central Estonia) to south (southern Finland) and north boreal (northern Finland) conditions was studied. Instantaneous fluxes varied between 0 and 1.3 g CO 2 -C m -2 h -1 , and annual fluxes between 248 and 515 g CO 2 -C m -2 a -1 . Variation in the annual fluxes among site types was studied only in the south-boreal site where we found a clear increase from nutrient-poor to nutrient-rich site types. More than half of the within-site variation was temporal and explained by soil surface (-5 cm) temperature (T5). The response of soil respiration to T5 varied between the sites; the most northerly site had the highest response to T5 and the most southerly the lowest. This trend further resulted in increased annual fluxes towards north. This unexpected result is hypothesised to be related to differences in site factors like substrate quality, nutrient status and hydrology but also to temperature acclimation, i.e., adaptation of decomposer populations to different climates. (orig.)

  18. Organic Matter Quality and its Influence on Carbon Turnover and Stabilization in Northern Peatlands

    Science.gov (United States)

    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

  19. Total and methyl mercury concentrations and fluxes from small boreal forest catchments in Finland

    International Nuclear Information System (INIS)

    Porvari, Petri; Verta, Matti

    2003-01-01

    Peatlands have higher methyl mercury output than uplands. - Total mercury (TotHg) and methyl mercury (MeHg) concentrations were studied in runoff from eight small (0.02-1.3 km 2 ) boreal forest catchments (mineral soil and peatland) during 1990-1995. Runoff waters were extremely humic (TOC 7-70 mg l -1 ). TotHg concentrations varied between 0.84 and 24 ng l -1 and MeHg between 0.03 and 3.8 ng l -1 . TotHg fluxes from catchments ranged from 0.92 to 1.8 g km -2 a -1 , and MeHg fluxes from 0.03 to 0.33 g km -2 a -1 . TotHg concentrations and output fluxes measured in runoff water from small forest catchments in Finland were comparable with those measured in other boreal regions. By contrast, MeHg concentrations were generally higher. Estimates for MeHg output fluxes in this study were comparable at sites with forests and wetlands in Sweden and North America, but clearly higher than those measured at upland or agricultural sites in other studies. Peatland catchments released more MeHg than pure mineral soil or mineral soil catchments with minor area of peatland

  20. Anthropogenic and geomorphic controls on peatland dynamics in contrasting floodplain environments during the Holocene and its impact on carbon storage

    Science.gov (United States)

    Verstraeten, Gert; Broothaerts, Nils; Notebaert, Bastiaan

    2016-04-01

    Peatlands are an important store of carbon in terrestrial environments, and scientific interest in peatlands has increased strongly in the light of the recent global climatic changes. Much attention has been paid to peatland dynamics in extensive arctic and boreal wetlands or to blanket peat in temperate regions. Nevertheless, long-term dynamics of peat in alluvial wetlands in temperate regions remains largely underresearched. In this study, data from three contrasting environments were used to provide more insights in the anthropogenic and geomorphic controls on peatland dynamics. The results show a high variability in alluvial peatland dynamics between the different study sites. In the central Belgian Loess Belt, alluvial peatlands developed during the early Holocene but gradually disappeared from the Mid-Holocene onwards due to the gradual intensification of agricultural activities in the catchment and consequent higher sedimentation rates in the floodplain system. The end of peat growth is shown to be diachronous at catchment scale, ranging between 6500 and 500 cal a BP. The disappearance of the alluvial peatlands has important implications since it potentially reduces the storage of locally produced C. Nevertheless, it was shown that this reduced production of local C but was outbalanced by the burial of hillslope derived C. Also within the sandy catchments of the Belgian Campine region alluvial peatlands initiated in the early Holocene but, here, they abruptly disappeared in the Mid-Holocene before the onset of intense agricultural activities in the catchment. This suggests that for the sandy regions, anthropogenic impact on peatland dynamics is less important compared to natural factors. For these regions, the disappearance of alluvial peatland formation resulted in a sharp decline in alluvial carbon storage as there is no compensation through hillslope derived C input. For the upper Dee catchment in NE Scotland, Holocene carbon floodplain storage varies

  1. Fluxes of methane and nitrogen oxides in various boreal mire ecosystems. Effects of land-use activities and environmental changes

    International Nuclear Information System (INIS)

    Martikainen, P.J.; Nykaenen, H.; Regina, K.; Alm, J.; Silvola, J.

    1996-01-01

    Atmospheric impact of peatlands is a sum of their gas fluxes. In contrast to carbon dioxide, peatlands are net sources for methane (CH 4 ). Methane is an end product in the anaerobic decomposition processes and it has greater capacity to absorb infrared radiation than carbon dioxide. Most of the data on the CH 4 release from northern peatlands is from North America. The total amount of methane released from wetlands is calculated to be 110 Tg yr -1 of which 34 percent (38 Tg yr -1 ) is estimated to be emitted from the northern peatlands. Peat with high content of nitrogen is a potential source for gaseous nitrogen oxides, i.e. nitrous oxide (N 2 O) and nitric oxide (NO). However, the importance of peatlands in producing these trace gases is poorly known. Nitrous oxide and nitric oxide are important components in the atmospheric chemistry and N 2 O also is an effective greenhouse gas. Land-use activities and environmental changes can affect the atmospheric impacts of peatlands by modifying their biogeochemistry. This article presents a short summary of the studies whose objectives were: (1) to measure fluxes of CH 4 and N 2 O on wide range of natural mires in Finland, (2) to study the short- and long-term changes in fluxes of CH 4 , N 2 O and NO on boreal peatlands after lowering their water table. Peatlands used for agriculture, forestry and peat mining were included in the studies. The results from mires drained for forestry may reflect the possible changes in the trace gas fluxes if water table will drop in the northern peatlands as a result of drier climate, (3) to study the effects of nitrogen load on the fluxes of CH 4 , N 2 O and NO, (4) to identify the microbiological processes important for the fluxes of N 2 O, NO and CH 4 , and to study the environmental factors regulating these microbial processes

  2. Controls on Ecosystem and Root Respiration in an Alaskan Peatland

    Science.gov (United States)

    McConnell, N. A.; McGuire, A. D.; Harden, J. W.; Kane, E. S.; Turetsky, M. R.

    2010-12-01

    Boreal ecosystems cover 14% of the vegetated surface on earth and account for 25-30% of the world’s soil carbon (C), mainly due to large carbon stocks in deep peat and frozen soil layers. While peatlands have served as historical sinks of carbon, global climate change may trigger re-release of C to the atmosphere and may turn these ecosystems into net C sources. Rates of C release from a peatland are determined by regional climate and local biotic and abiotic factors such as vegetation cover, thaw depth, and peat thickness. Soil CO2 fluxes are driven by both autotrophic (plant) respiration and heterotrophic (microbial) respiration. Thus, changes in plant and microbial activity in the soil will impact CO2 emissions from peatlands. In this study, we explored environmental and vegetation controls on ecosystem respiration and root respiration in a variety of wetland sites. The study was conducted at the Alaskan Peatland Experiment (APEX; www.uoguelph.ca/APEX) sites in the Bonanza Creek Experimental Forest located 35 km southwest of Fairbanks Alaska. We measured ecosystem respiration, root respiration, and monitored a suite of environmental variables along a vegetation and soil moisture gradient including a black spruce stand with permafrost, a shrubby site with permafrost, a tussock grass site, and a herbaceous open rich fen. Within the rich fen, we have been conducting water table manipulations including a control, lowered, and raised water table treatment. In each of our sites, we measured total ecosystem respiration using static chambers and root respiration by harvesting roots from the uppermost 20 cm and placing them in a root cuvette to obtain a root flux. Ecosystem respiration (ER) on a μmol/m2/sec basis varied across sites. Water table was a significant predictor of ER at the lowered manipulation site and temperature was a strong predictor at the control site in the rich fen. Water table and temperature were both significant predictors of ER at the raised

  3. Peatland succession induces a shift in the community composition of Sphagnum-associated active methanotrophs.

    Science.gov (United States)

    Putkinen, Anuliina; Larmola, Tuula; Tuomivirta, Tero; Siljanen, Henri M P; Bodrossy, Levente; Tuittila, Eeva-Stiina; Fritze, Hannu

    2014-06-01

    Sphagnum-associated methanotrophs (SAM) are an important sink for the methane (CH4) formed in boreal peatlands. We aimed to reveal how peatland succession, which entails a directional change in several environmental variables, affects SAM and their activity. Based on the pmoA microarray results, SAM community structure changes when a peatland develops from a minerotrophic fen to an ombrotrophic bog. Methanotroph subtypes Ia, Ib, and II showed slightly contrasting patterns during succession, suggesting differences in their ecological niche adaptation. Although the direct DNA-based analysis revealed a high diversity of type Ib and II methanotrophs throughout the studied peatland chronosequence, stable isotope probing (SIP) of the pmoA gene indicated they were active mainly during the later stages of succession. In contrast, type Ia methanotrophs showed active CH4 consumption in all analyzed samples. SIP-derived (13)C-labeled 16S rRNA gene clone libraries revealed a high diversity of SAM in every succession stage including some putative Methylocella/Methyloferula methanotrophs that are not detectable with the pmoA-based approach. In addition, a high diversity of 16S rRNA gene sequences likely representing cross-labeled nonmethanotrophs was discovered, including a significant proportion of Verrucomicrobia-related sequences. These results help to predict the effects of changing environmental conditions on SAM communities and activity. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  4. Responsible management of peatlands in Canada, from peat industry to oil sands

    Science.gov (United States)

    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.

  5. Do Peatlands Hibernate?

    Science.gov (United States)

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

    2014-12-01

    . Altogether, our data indicate that peatlands are active in winter. However, a continuous snow cover is crucial for ecosystem processes both in winter and in the subsequent summer and a reduction of snow thickness or duration due to climate change may impact on peatland ecosystem functioning at various levels.

  6. Impact of an abrupt cooling event on interglacial methane emissions in northern peatlands

    Directory of Open Access Journals (Sweden)

    S. Zürcher

    2013-03-01

    Full Text Available Rapid changes in atmospheric methane (CH4, temperature and precipitation are documented by Greenland ice core data both for glacial times (the so called Dansgaard-Oeschger (D-O events as well as for a cooling event in the early Holocene (the 8.2 kyr event. The onsets of D-O warm events are paralleled by abrupt increases in CH4 by up to 250 ppb in a few decades. Vice versa, the 8.2 kyr event is accompanied by an intermittent decrease in CH4 of about 80 ppb over 150 yr. The abrupt CH4 changes are thought to mainly originate from source emission variations in tropical and boreal wet ecosystems, but complex process oriented bottom-up model estimates of the changes in these ecosystems during rapid climate changes are still missing. Here we present simulations of CH4 emissions from northern peatlands with the LPJ-Bern dynamic global vegetation model. The model represents CH4 production and oxidation in soils and transport by ebullition, through plant aerenchyma, and by diffusion. Parameters are tuned to represent site emission data as well as inversion-based estimates of northern wetland emissions. The model is forced with climate input data from freshwater hosing experiments using the NCAR CSM1.4 climate model to simulate an abrupt cooling event. A concentration reduction of ~10 ppb is simulated per degree K change of mean northern hemispheric surface temperature in peatlands. Peatland emissions are equally sensitive to both changes in temperature and in precipitation. If simulated changes are taken as an analogy to the 8.2 kyr event, boreal peatland emissions alone could only explain 23% of the 80 ppb decline in atmospheric methane concentration. This points to a significant contribution to source changes from low latitude and tropical wetlands to this event.

  7. The peatland map of Europe

    Czech Academy of Sciences Publication Activity Database

    Tannenberger, F.; Tagetmeyer, C.; Busse, S.; Barthelmes, A.; Shumka, S.; Moles Mariné, A.; Jenderedjian, K.; Steiner, G. M.; Essl, F.; Etzold, J.; Mendes, C.; Kozulin, A.; Frankard, P.; Milanović, Ð.; Ganeva, A.; Apostolova, I.; Alegro, A.; Delipetrou, P.; Navrátilová, Jana; Risager, M.; Leivits, A.; Fosaa, A. M.; Tuominen, S.; Muller, F.; Bakuradze, T.; Sommer, M.; Christanis, K.; Szurdoki, E.; Oskarsson, H.; Brink, S. H.; Cannolly, J.; Bragazza, L.; Martinelli, G.; Aleksāns, O.; Priede, A.; Sungaila, D.; Melovski, L.; Belous, T.; Saveljić, D.; de Vries, F.; Moen, A.; Demberk, W.; Mateus, J.; Hanganu, J.; Sirin, A.; Markina, A.; Napreenko, M.; Lazarević, P.; Šefferová Stanová, V.; Skoberne, P.; Heras Peréz, P.; Pontevedra-Pombal, X.; Lonnstad, J.; Küchler, M.; Wüst-Galley, C.; Kirca, S.; Mykytiuk, O.; Lindsay, R.; Joosten, H.

    2017-01-01

    Roč. 19, nov 2017 (2017), č. článku 22. ISSN 1819-754X Institutional support: RVO:67985939 Keywords : peatland * distribution * map Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 1.129, year: 2016

  8. Evapotranspiration from two peatland watersheds

    Science.gov (United States)

    Roger R. Bay

    1968-01-01

    Measurements of precipitation, runoff, and bog water table levels have provided data for the calculation of evapotranspiration from two forested peatland watersheds near Grand Rapids, Minnesota (ca. 47? 32'N, 93? 28'W). Continuous hydrologie records were collected on one experimental bog for 6 years (1961-1966) and on the other for the past 2 years (1965-1966...

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

    Science.gov (United States)

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

    2013-02-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  11. Emission factors and their uncertainty for the exchange of CO2, CH4 and N2O in Finnish managed peatlands

    International Nuclear Information System (INIS)

    Alm, J.; Shurpali, N. J.; Minkkinen, K.

    2007-01-01

    This paper summarises the results of several research groups participating in the research programme 'Greenhouse Impacts of the use of Peat and Peatlands in Finland', and presents emission factors for peat-atmosphere fluxes of CO 2 , CH 4 , and N 2 O, filling gaps in knowledge concerning the afforestation of organic croplands and cutaways, and improves the emission assessment of peatlands drained for forestry. Forest drainage may result in net binding of soil carbon or net release, depending on site characteristics and the tree stand. Use of peatlands for agriculture (48-4821 g CO 2 -eq. m -2 a -1 ), even after the cultivation has ceased, or for milled peat harvesting (1948-2478 g CO 2 -eq. m -2 a -1 ) can cause the highest overall emissions. Extremely high CO 2 emissions are possible from peat harvesting areas during wet and warm summers. Afforestation of those peatlands abandoned from cultivation or peat harvesting can reduce the warming impact at least during the first tree generation. Heterotrophic soil respiration may have a systematic south-north difference in temperature response. More data must be collected before the information on peatland forest soil CO 2 emissions can be adapted for different climatic regions in Finland. A test of the model DNDC against measured data showed that DNDC has to be developed further before it can be used in estimating N 2 O emissions from boreal peatlands. (orig.)

  12. Buffers Plus

    Science.gov (United States)

    Ramette, Richard W.

    1998-11-01

    In 1989 JCE Software published The Acid-Base Package: A Collection of Useful Programs for Proton Transfer Systems (Ramette, R. W. J. Chem. Educ. Software 1989, 2B No. 2). This DOS program has been fully upgraded by the same author to the world of Windows 95. Buffers Plus takes advantage of a modern user interface and offers many new options not possible in the original version.

  13. Buffer fluid

    Energy Technology Data Exchange (ETDEWEB)

    Mirzadzhanzade, A Kh; Dedusanko, G Ya; Dinaburg, L S; Markov, Yu M; Rasizade, Ya N; Rozov, V N; Sherstnev, N M

    1979-08-30

    A drilling fluid is suggested for separating the drilling and plugging fluids which contains as the base increased solution of polyacrylamide and additive. In order to increase the viscoelastic properties of the liquid with simultaneous decrease in the periods of its fabrication, the solution contains as an additive dry bentonite clay. In cases of the use of a buffer fluid under conditions of negative temperatures, it is necessary to add to it table salt or ethylene glycol.

  14. Some results on the isotope studies of water exchange in boreal raised bogs

    International Nuclear Information System (INIS)

    Sirin, A.A.; Vlasova, L.S.; Polyakov, V.A.; Trofimova, A.E.

    2002-01-01

    Raised bogs are rather common and one of the most exciting mire types of the boreal zone. They receive water and nutrients from precipitation and pore water stored in their domes (up to 10 m in height) is spaced above levels of regional ground water or streams draining them. Peatland hydrologists have long assumed that fluid flow occurs mainly in a peat layer near to the surface and water transport is negligible in deeper layers. The 'acrotelm/catotelm' paradigm on active and inert horizons for the peat above and below the lowest water level is still widely spread in peatland hydrology. However, recent studies have shown that deep water movement is much more dynamic in raised bogs than was previously thought. Based on geochemical studies and numerical simulations even temporal reverse of the vertical direction of water fluid flow through the peat as connected to climate fluctuations was assumed. Relying on isotope studies we consider only the mounded strata of the raised bogs to have relatively active water exchange. The study included two raised bogs, representing different local hydrological conditions (underlain by outwash sands and moraine clay) at the Zapadnaya Dvina Peatland Field Station of the Forest Research Institute located 400 km west of Moscow. Peatlands, among which raised bogs dominate, constitute >30% of the area, and maximum peat thickness exceeds 7 m

  15. A cross-scale framework of peatland resilience based on long-term research in interior Alaska and the Northwest Territories, Canada

    Science.gov (United States)

    Turetsky, M. R.; Kane, E. S.; Baltzer, J. L.; Quinton, W. L.; Euskirchen, E. S.; Sonnentag, O.; Waldrop, M. P.; Neumann, R.; Douglas, T.

    2017-12-01

    Considerable progress has been made in recent decades towards understanding northern ecosystem structure and function in the context of resilience theory. For example, there is increasing understanding that wildfire activity is overwhelming the resilience mechanisms of conifer species, shifting forest composition toward deciduous cover in some boreal regions. Relative to forests and grasslands, we have less knowledge on what governs the response of northern peatlands to disturbance, including drought, wildfire, and permafrost thaw. The majority of peatland research to date has instead focused on ecological and hydrological measurements across fen-to-bog or hummock-to-hollow gradients. It was only recently appreciated that fire serves as an important agent of successional change in northern peatlands, as recent studies show that peat accumulation and the function of peatlands as net carbon sinks requires light to moderate fire activity. In this presentation, we will synthesize results from water table and vegetation manipulation experiments, continuous ecosystem-scale measurements of carbon, energy and water fluxes, and observations across gradients of fire severity and permafrost thaw to derive a mechanistic framework of peatland ecological and hydrological resilience. In particular, we will highlight the past decade of observations made at the Scotty Creek Research Station in the Northwest Territories as well as the Alaska Peatland Experiment (APEX) in interior Alaska. Our research shows that vegetation, particularly deep rooting early successional species and late successional mosses, play a critical role in maintaining nutrient cycling and ecosystem carbon balance in a peat accumulating state. Peatlands also govern how the surrounding landscape responds to drought, fire, and permafrost thaw. Future research needs to consider the resilience of northern ecosystems at a variety of spatio-temporal scales through a combination of ground measurements, remote sensing

  16. Changes in Pore Water Quality After Peatland Restoration: Assessment of a Large-Scale, Replicated Before-After-Control-Impact Study in Finland

    Science.gov (United States)

    Menberu, Meseret Walle; Marttila, Hannu; Tahvanainen, Teemu; Kotiaho, Janne S.; Hokkanen, Reijo; Kløve, Bjørn; Ronkanen, Anna-Kaisa

    2017-10-01

    Drainage is known to affect peatland natural hydrology and water quality, but peatland restoration is considered to ameliorate peatland degradation. Using a replicated BACIPS (Before-After-Control-Impact Paired Series) design, we investigated 24 peatlands, all drained for forestry and subsequently restored, and 19 pristine control boreal peatlands with high temporal and spatial resolution data on hydroclimate and pore water quality. In drained conditions, total nitrogen (Ntot), total phosphorus (Ptot), and dissolved organic carbon (DOC) in pore water were several-fold higher than observed at pristine control sites, highlighting the impacts of long-term drainage on pore water quality. In general, pore water DOC and Ntot decreased after restoration measures but still remained significantly higher than at pristine control sites, indicating long time lags in restoration effects. Different peatland classes and trophic levels (vegetation gradient) responded differently to restoration, primarily due to altered hydrology and varying acidity levels. Sites that were hydrologically overrestored (inundated) showed higher Ptot, Ntot, and DOC than well-restored or insufficiently restored sites, indicating the need to optimize natural-like hydrological regimes when restoring peatlands drained for forestry. Rich fens (median pH 6.2-6.6) showed lower pore water Ptot, Ntot, and DOC than intermediate and poor peats (pH 4.0-4.6) both before and after restoration. Nutrients and DOC in pore water increased in the first year postrestoration but decreased thereafter. The most important variables related to pore water quality were trophic level, peatland class, water table level, and soil and air temperature.

  17. Newtonian boreal forest ecology

    OpenAIRE

    Hari, Pertti; Aakala, Tuomas; Aalto, Juho; Bäck, Jaana; Hollmén, Jaakko; Jõgiste, Kalev; Koupaei, Kourosh Kabiri; Kähkönen, Mika A.; Korpela, Mikko; Kulmala, Liisa; Nikinmaa, Eero; Pumpanen, Jukka; Salkinoja-Salonen, Mirja; Schiestl-Aalto, Pauliina; Simojoki, Asko

    2017-01-01

    Isaac Newton's approach to developing theories in his book Principia Mathematica proceeds in four steps. First, he defines various concepts, second, he formulates axioms utilising the concepts, third, he mathematically analyses the behaviour of the system defined by the concepts and axioms obtaining predictions and fourth, he tests the predictions with measurements. In this study, we formulated our theory of boreal forest ecosystems, called NewtonForest, following the four steps introduced by...

  18. Peatland-GHG emissions in Europe

    Science.gov (United States)

    Droesler, Matthias

    2013-04-01

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

  19. A Soil Service Index: Peatland soils as a case study for quantifying the value, vulnerability, and status of soils

    Science.gov (United States)

    Loisel, J.; Harden, J. W.; Hugelius, G.

    2017-12-01

    What are the most important soil services valued by land stewards and planners? Which soil-data metrics can be used to quantify each soil service? What are the steps required to quantitatively index the baseline value of soil services and their vulnerability under different land-use and climate change scenarios? How do we simulate future soil service pathways (or trajectories) under changing management regimes using process-based ecosystem models? What is the potential cost (economic, social, and other) of soil degradation under these scenarios? How sensitive or resilient are soil services to prescribed management practices, and how does sensitivity vary over space and time? We are bringing together a group of scientists and conservation organizations to answer these questions by launching Soil Banker, an open and flexible tool to quantify soil services that can be used at any scale, and by any stakeholder. Our overarching goals are to develop metrics and indices to quantify peatland soil ecosystem services, monitor change of these services, and guide management. This paper describes our methodology applied to peatlands and presents two case studies (Indonesia and Patagonia) demonstrating how Peatland Soil Banker can be deployed as an accounting tool of peatland stocks, a quantitative measure of peatland health, and as a projection of peatland degradation or enhancement under different land-use cases. Why peatlands? They store about 600 billion tons of carbon that account for ⅓ of the world's soil carbon. Peatlands have dynamic GHG exchanges of CO2, CH4, and NOx with the atmosphere, which plays a role in regulating global climate; studies indicate that peatland degradation releases about 2-3 billion tons of CO2 to the atmosphere annually. These ecosystems also provide local and regional ecosystem services: they constitute important components of the N and P cycles, store about 10% of the world's freshwater and buffer large fluxes of freshwater on an annual basis

  20. Peatland pines as a proxy for water table fluctuations: disentangling tree growth, hydrology and possible human influence.

    Science.gov (United States)

    Smiljanić, Marko; Seo, Jeong-Wook; Läänelaid, Alar; van der Maaten-Theunissen, Marieke; Stajić, Branko; Wilmking, Martin

    2014-12-01

    Dendrochronological investigations of Scots pine (Pinus sylvestris L.) growing on Männikjärve peatland in central Estonia showed that annual tree growth of peatland pines can be used as a proxy for past variations of water table levels. Reconstruction of past water table levels can help us to better understand the dynamics of various ecological processes in peatlands, e.g. the formation of vegetation patterns or carbon and nitrogen cycling. Männikjärve bog has one of the longest water table records in the boreal zone, continuously monitored since 1956. Common uncertainties encountered while working with peatland trees (e.g. narrow, missing and wedging rings) were in our case exacerbated with difficulties related to the instability of the relationship between tree growth and peatland environment. We hypothesized that the instable relationship was mainly due to a significant change of the limiting factor, i.e. the rise of the water table level due to human activity. To test our hypothesis we had to use several novel methods of tree-ring chronology analysis as well as to test explicitly whether undetected missing rings biased our results. Since the hypothesis that the instable relationship between tree growth and environment was caused by a change in limiting factor could not be rejected, we proceeded to find possible significant changes of past water table levels using structural analysis of the tree-ring chronologies. Our main conclusions were that peatland pines can be proxies to water table levels and that there were several shifting periods of high and low water table levels in the past 200 years. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Soils of peatlands: histosols and gelisols

    Science.gov (United States)

    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...

  2. Towards sustainable management of Indonesian tropical peatlands

    NARCIS (Netherlands)

    Uda, Saritha Kittie; Hein, Lars; Sumarga, Elham

    2017-01-01

    Large areas of Indonesian peatlands have been converted for agricultural and plantation forest purposes. This requires draining with associated CO2 emissions and fire risks. In order to identify alternative management regimes for peatlands, it is important to understand the

  3. Influence of the permafrost boundary on dissolved organic matter characteristics in rivers within the Boreal and Taiga plains of western Canada

    International Nuclear Information System (INIS)

    Olefeldt, D; Turetsky, M R; Persson, A

    2014-01-01

    Catchment export of terrestrial dissolved organic matter (DOM) and its downstream degradation in aquatic ecosystems are important components of landscape scale carbon balances. In order to assess the influence of peatland permafrost on river DOM characteristics, we sampled 65 rivers along a 900 km transect crossing into the southern discontinuous permafrost zone on the Boreal and Tundra Plains of western Canada. Catchment peatland cover and catchment location north or south of the permafrost boundary were found together to have strong influences on dissolved organic carbon (DOC) concentrations and DOM chemical composition. River DOC concentrations increased with catchment peatland cover, but were consistently lower for catchments north of the permafrost boundary. In contrast, protein fluorescence (PARAFAC analysis), was unrelated to catchment peatland cover but increased significantly in rivers north of the permafrost boundary. Humic and fulvic acid contribution to DOM fluorescence was lower in rivers draining catchments with large lakes than in other rivers, consistent with extensive photodegradation, but humic and fulvic acid fluorescence were also lower in rivers north of the permafrost boundary than in rivers to the south. We hypothesize that shifts in river DOM characteristics when crossing the permafrost boundary are related to the influence of permafrost on peatland hydrological connectivity to stream networks, peatland DOM characteristics and differences in DOM degradation within aquatic ecosystems. (paper)

  4. The Acid-Base Balance Between Organic Acids and Circumneutral Ground Waters in Large Peatlands

    Science.gov (United States)

    Siegel, D. I.; Glaser, P. H.; So, J.

    2006-05-01

    Organic acids supply most of the acidity in the surface waters of bogs in peatlands. Yet, the fundamental geochemical properties of peatland organic acids are still poorly known. To assess the geochemical properties of typical organic acid assemblages in peatlands, we used a triprotic analog model for peat pore waters and surface waters in the Glacial Lake Agassiz Peatlands, optimizing on charge balance and calibrated to estimates of mole site density in DOC and triprotic acid dissociation constants. Before the calibration process, all bog waters and 76% of fen waters had more than +20% charge imbalance. After calibration, most electrochemically balanced within 20%. In the best calibration, the mole site denisty of bog DOC was estimated as ~0.05 mmol/mmol C., approximately 6 times smaller than that for fen DOC or the DOC in the fen deeper fen peats that underlie bogs. The three modeled de-protonation constants were; pKa1 = ~3.0, pKa2 = ~4.5 and pKa3 = ~7.0 for the bog DOC, and; pKa1 = ~5.2, pKa2 =~ 6.5 and pKa3 = ~7.0 for the fen DOC. Bog DOC, behaves as a strong acid despite its small mole site density. The DOC in bog runoff can therefore theoretically acidify the surface waters in adjacent fens wherever these waters do not receive sufficient buffering alkalinity from active groundwater seepage.

  5. How can we conserve intact tropical peatlands?

    Science.gov (United States)

    Lawson, Ian; Roucoux, Katherine

    2017-04-01

    The scientific community has, for more than three decades, been expressing increasing alarm about the fate of peatlands in parts of Indonesia and Malaysia, where extensive land-use conversion and drainage for rice and oil palm have greatly compromised peatland hydrology, ecology, biological richness, and carbon storage. The discourse in the literature on these peatlands is now moving on from attempts to preserve the last remaining fragments of peat-swamp forest, towards discussion of how best to restore damaged ecosystems, and whether it is possible to manage plantations more 'sustainably'. It is becoming increasingly clear, however, that peatlands occur quite widely in other parts of the lowland tropics, including parts of Amazonia and the Congo Basin, and many of these peatlands can reasonably be described as 'intact': although few if any parts of the tropics are totally unaffected by human actions, the hydrology and functional ecology of these systems appear to be close to a 'natural' state. The question then arises as to what should be done with the knowledge of their existence. Here we analyse the arguments in favour of protecting intact peatlands, and the potential conflicts with other priorities such as economic development and social justice. We evaluate alternative mechanisms for protecting intact peatlands, focusing on the particular issues raised by peatlands as opposed to other kinds of tropical ecosystem. We identify ways in which natural science agendas can help to inform these arguments, using our own contributions in palaeoecology and carbon mapping as examples. Finally, we argue for a radical reconsideration of research agendas in tropical peatlands, highlighting the potential contribution of methodologies borrowed from the social sciences and humanities.

  6. Methanotrophy induces nitrogen fixation during peatland development

    Science.gov (United States)

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

    2014-01-01

    Nitrogen (N) accumulation rates in peatland ecosystems indicate significant biological atmospheric N2 fixation associated with Sphagnum mosses. Here, we show that the linkage between methanotrophic carbon cycling and N2 fixation may constitute an important mechanism in the rapid accumulation of N during the primary succession of peatlands. In our experimental stable isotope enrichment study, previously overlooked methane-induced N2 fixation explained more than one-third of the new N input in the younger peatland stages, where the highest N2 fixation rates and highest methane oxidation activities co-occurred in the water-submerged moss vegetation. PMID:24379382

  7. Restoration techniques for Sphagnum-dominated peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Ferland, C.; Rochefort, L. [Laval University, Sainte-Foy, PQ (Canada). Department of Phytology

    1997-07-01

    After peat harvesting, peat mosses do not usually recolonize the abandoned site. The purpose of this study is to develop techniques for restoring peatlands. Sphagnum diaspores from natural peatlands were introduced to exploited peatlands. The influence of microrelief, of planting companion species with the Sphagnum, and of light phosphorus fertilization on establishment of a peat moss carpet are examined. The results show that Sphagnum diaspores can be reintroduced on bare peat surfaces. The restoration method is combined with techniques to improve substrata moisture conditions, such as creation of surface roughness and the use of companion plant species. 32 refs., 6 figs., 3 tabs.

  8. Fluxes of methane and nitrogen oxides in various boreal mire ecosystems. Effects of land-use activities and environmental changes

    Energy Technology Data Exchange (ETDEWEB)

    Martikainen, P.J.; Nykaenen, H.; Regina, K. [National Public Health Inst., Kuopio (Finland). Lab. of Environmental Microbiology; Alm, J.; Silvola, J. [Joensuu Univ. (Finland). Dept. of Biology

    1996-12-31

    Atmospheric impact of peatlands is a sum of their gas fluxes. In contrast to carbon dioxide, peatlands are net sources for methane (CH{sub 4}). Methane is an end product in the anaerobic decomposition processes and it has greater capacity to absorb infrared radiation than carbon dioxide. Most of the data on the CH{sub 4} release from northern peatlands is from North America. The total amount of methane released from wetlands is calculated to be 110 Tg yr{sup -1} of which 34 percent (38 Tg yr{sup -1}) is estimated to be emitted from the northern peatlands. Peat with high content of nitrogen is a potential source for gaseous nitrogen oxides, i.e. nitrous oxide (N{sub 2}O) and nitric oxide (NO). However, the importance of peatlands in producing these trace gases is poorly known. Nitrous oxide and nitric oxide are important components in the atmospheric chemistry and N{sub 2}O also is an effective greenhouse gas. Land-use activities and environmental changes can affect the atmospheric impacts of peatlands by modifying their biogeochemistry. This article presents a short summary of the studies whose objectives were: (1) to measure fluxes of CH{sub 4} and N{sub 2}O on wide range of natural mires in Finland, (2) to study the short- and long-term changes in fluxes of CH{sub 4}, N{sub 2}O and NO on boreal peatlands after lowering their water table. Peatlands used for agriculture, forestry and peat mining were included in the studies. The results from mires drained for forestry may reflect the possible changes in the trace gas fluxes if water table will drop in the northern peatlands as a result of drier climate, (3) to study the effects of nitrogen load on the fluxes of CH{sub 4}, N{sub 2}O and NO, (4) to identify the microbiological processes important for the fluxes of N{sub 2}O, NO and CH{sub 4}, and to study the environmental factors regulating these microbial processes

  9. Fluxes of methane and nitrogen oxides in various boreal mire ecosystems. Effects of land-use activities and environmental changes

    Energy Technology Data Exchange (ETDEWEB)

    Martikainen, P J; Nykaenen, H; Regina, K [National Public Health Inst., Kuopio (Finland). Lab. of Environmental Microbiology; Alm, J; Silvola, J [Joensuu Univ. (Finland). Dept. of Biology

    1997-12-31

    Atmospheric impact of peatlands is a sum of their gas fluxes. In contrast to carbon dioxide, peatlands are net sources for methane (CH{sub 4}). Methane is an end product in the anaerobic decomposition processes and it has greater capacity to absorb infrared radiation than carbon dioxide. Most of the data on the CH{sub 4} release from northern peatlands is from North America. The total amount of methane released from wetlands is calculated to be 110 Tg yr{sup -1} of which 34 percent (38 Tg yr{sup -1}) is estimated to be emitted from the northern peatlands. Peat with high content of nitrogen is a potential source for gaseous nitrogen oxides, i.e. nitrous oxide (N{sub 2}O) and nitric oxide (NO). However, the importance of peatlands in producing these trace gases is poorly known. Nitrous oxide and nitric oxide are important components in the atmospheric chemistry and N{sub 2}O also is an effective greenhouse gas. Land-use activities and environmental changes can affect the atmospheric impacts of peatlands by modifying their biogeochemistry. This article presents a short summary of the studies whose objectives were: (1) to measure fluxes of CH{sub 4} and N{sub 2}O on wide range of natural mires in Finland, (2) to study the short- and long-term changes in fluxes of CH{sub 4}, N{sub 2}O and NO on boreal peatlands after lowering their water table. Peatlands used for agriculture, forestry and peat mining were included in the studies. The results from mires drained for forestry may reflect the possible changes in the trace gas fluxes if water table will drop in the northern peatlands as a result of drier climate, (3) to study the effects of nitrogen load on the fluxes of CH{sub 4}, N{sub 2}O and NO, (4) to identify the microbiological processes important for the fluxes of N{sub 2}O, NO and CH{sub 4}, and to study the environmental factors regulating these microbial processes

  10. Buffer mass test - Buffer materials

    International Nuclear Information System (INIS)

    Pusch, R.; Boergesson, L.

    1982-08-01

    Commercial Na bentonite (MX-80) is the clay component of the buffer material in the heater holes as well of the tunnel backfill. Important characteristics are the clay content, liquid limit, X-ray diffraction pattern, water content, and degree of granulation. The ballast material consists of quartz-rich sand and feldspar-rich filler. The preparation of highly compacted bentonite for the near-field isolation of the canister was made by using isostatic compaction technique. The resulting dense bentonite core was cut into regularly shaped blocks which were arranged around each heater and lowered as one unit - heavily instrumented - in the respective deposition holes. For three of the six holes a narrow slot was left open between the bentonite stack and the rock; for the remaining ones a wider slot was chosen with a fill of soft bentonite powder. Both arrangements are expected to yield an ultimate bulk density which is sufficiently high to fulfil the requirement of a negligible permeability and a sufficient swelling pressure as well as heat conductivity, which are the essential parameters. The tunnel backfill, which consists of a mixture of suitably graded ballast material and MX-80 powder, has a considerably lower swelling pressure and heat conductivity, and a higher permeability, all these parameters still within the requirements of the KBS 2 concept. The various zones with different bentonite/sand ratios and the technique to apply them are described in the final part of the report. (Author)

  11. Trace gas fluxes from northern peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Moore, T [McGill Univ., Montreal (Canada). Geography Dept.

    1997-12-31

    Peatlands cover large areas in northern environments: 1.1, 0.1 and 1.7 x 10{sup 4} km{sup 2} in Canada, Finland and the former Soviet Union, respectively. Interest has been generated into the role these extensive areas of peatlands play in controlling the chemistry of the atmosphere. In particular, it has become established that peatlands can be a source of methane (CH{sub 4}) and nitrous oxide (N{sub 2}O), and a sink of carbon dioxide (CO{sub 2}), the latter through the rates of plant production exceeding the rate of decomposition of plant material and peat. In this presentation the recent advances in trace gas flux measurements in northern peatlands are presented. (16 refs.)

  12. Trace gas fluxes from northern peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Moore, T. [McGill Univ., Montreal (Canada). Geography Dept.

    1996-12-31

    Peatlands cover large areas in northern environments: 1.1, 0.1 and 1.7 x 10{sup 4} km{sup 2} in Canada, Finland and the former Soviet Union, respectively. Interest has been generated into the role these extensive areas of peatlands play in controlling the chemistry of the atmosphere. In particular, it has become established that peatlands can be a source of methane (CH{sub 4}) and nitrous oxide (N{sub 2}O), and a sink of carbon dioxide (CO{sub 2}), the latter through the rates of plant production exceeding the rate of decomposition of plant material and peat. In this presentation the recent advances in trace gas flux measurements in northern peatlands are presented. (16 refs.)

  13. Thresholds for boreal biome transitions.

    Science.gov (United States)

    Scheffer, Marten; Hirota, Marina; Holmgren, Milena; Van Nes, Egbert H; Chapin, F Stuart

    2012-12-26

    Although the boreal region is warming twice as fast as the global average, the way in which the vast boreal forests and tundras may respond is poorly understood. Using satellite data, we reveal marked alternative modes in the frequency distributions of boreal tree cover. At the northern end and at the dry continental southern extremes, treeless tundra and steppe, respectively, are the only possible states. However, over a broad intermediate temperature range, these treeless states coexist with boreal forest (∼75% tree cover) and with two more open woodland states (∼20% and ∼45% tree cover). Intermediate tree covers (e.g., ∼10%, ∼30%, and ∼60% tree cover) between these distinct states are relatively rare, suggesting that they may represent unstable states where the system dwells only transiently. Mechanisms for such instabilities remain to be unraveled, but our results have important implications for the anticipated response of these ecosystems to climatic change. The data reveal that boreal forest shows no gradual decline in tree cover toward its limits. Instead, our analysis suggests that it becomes less resilient in the sense that it may more easily shift into a sparse woodland or treeless state. Similarly, the relative scarcity of the intermediate ∼10% tree cover suggests that tundra may shift relatively abruptly to a more abundant tree cover. If our inferences are correct, climate change may invoke massive nonlinear shifts in boreal biomes.

  14. Northern peatlands in global climatic change

    Energy Technology Data Exchange (ETDEWEB)

    Laiho, R.; Laine, J.; Vasander, H. [eds.] [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1996-12-31

    Northern peatlands are important in regulating the global climate. While sequestering carbon dioxide, these peatlands release ca. 24-39 Tg methane annually to the atmosphere. This is 5-20 % of the annual anthropogenic methane emissions to the atmosphere. The greenhouse gas balance of peatlands may change as a consequence of water level draw-down after land-use change, or if summers become warmer and drier, as has been predicted for high latitudes after climatic warming. Subsequent emissions of methane would decrease, whereas emissions of carbon dioxide and nitrous oxide would increase. Within the Finnish Research Programme on Climate Change (SILMU), the research project `Carbon Balance of Peatlands and Climate Change` (SUOSILMU) has been under progress since 1990. It is a co-operative research project, with research groups from the Universities of Helsinki and Joensuu, the Finnish Forest Research Institute, the National Public Health Institute and the Finnish Environment Agency. The research consortium of this project organised a workshop entitled `Northern Peatlands in Global Climatic Change - Hyytiaelae Revisited` October 8-12, 1995. The main objective of the workshop was to review the state of the art of the carbon cycling research in natural and managed peatlands. The role of peatlands in the greenhouse effect, their response and feedback to the predicted climate change, and the consequences of land-use changes were assessed, and the future research needs were evaluated. The latest information on the role of peatlands in the atmospheric change was given in 50 posters and 4 key lectures. Results of SUOSILMU projects were demonstrated during a 1-day field excursion to one of the intensive study sites, Lakkasuo near Hyytiaelae

  15. Simulating groundwater-peatland interactions in depression and slope peatlands in southern Quebec (Canada)

    Science.gov (United States)

    Larocque, M.; Quillet, A.; Paniconi, C.

    2013-12-01

    It is crucial to understand hydrogeological interactions between aquifers and peatlands in order to grasp the influence of aquifers in peatland water budgets, to understand the role of groundwater in the evolution or organic matter deposition, and to quantify how a peatland can sustain groundwater levels in a superficial aquifer. These questions have rarely been addressed in literature and there is currently no understanding of which process dominates aquifer-peatland exchanges in different geomorphological settings. The main purpose of the study was to use groundwater flow modeling to answer these questions in two contrasted geological contexts of southern Quebec (Canada). During a three-year study, six peatlands have been instrumented in the Becancour (Centre-du-Quebec) and Amos (Abitibi-Temiscamingue) regions of southern Quebec (Canada). At each site, either one or two transects of six piezometer nests (at 1.20 m depth in the organic deposits and in the mineral deposits below the peat) have been installed, for a total of twelve aquifer-peatland transects of approximately 500 m. The stratigraphy and geometry of the peatland-aquifer system, as well as the hydrodynamic properties of the organic and mineral deposits have been measured at all sites. Groundwater levels have been recorded from autumn 2010 to summer 2012. The Becancour peatlands have developed in depressions while the Amos peatlands have developed through the paludification of esker slopes. The maximum peat thickness measured in the Bécancour peatlands is 6.4 m while it is 4.5 m in the Amos region. In both regions, peatlands are fringed by sandy deposits that extend at least partly under the organic deposits. The thickness of these underlying deposits is not well defined, but available data suggests a metric scale thickness in areas close to the adjacent superficial aquifer. Field data is used to create 2D numerical models in Modflow to simulate flow between the shallow groundwater and the peatland on

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

    Science.gov (United States)

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

    2016-06-01

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

  17. Controls on boreal peat combustion and resulting emissions of carbon and mercury

    Science.gov (United States)

    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.

  18. Energy potential of Finnish peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Virtanen, K. (Geological Survey of Finland, Kuopio (Finland)); Valpola, S. (Geological Survey of Finland, Kokkola (Finland)), e-mail: kimmo.virtanen@gtk.fi, e-mail: samu.valpola@gtk.fi

    2011-07-01

    One-third of the Finnish land area is covered by mires and peat. GTK has investigated 2.0 million ha of the 9.3 million ha area covered by mires in Finland. According to the EU Commission, the broadly-based Finnish energy economy, with various energy sources, is the best in the EU. As a fuel, peat fulfils the goals of the EU energy policy in Finland well: it is local, its availability is good and the price is stable. The use of peat also enhances national security. At present, peat is used in around one hundred larger applications that co-generate electricity and heat. In Finland, the development of mires has led to several mire complex types and three main types: raised bogs in Southern Finland, aapa mires in Ostrobothnia and Lapland, and palsa mires in Northern Lapland. Peat layers are deepest in southern Finland and partly in the southern Finnish Lake area, the Region of North Karelia and in the area of central Lapland. The mean depth of geological mires is 1.41 m and the thickest drilled peat is 12.3 m. According to peat investigations, the national peat reserve totals 69.3 billion m3 in situ (peatlands larger than 20 hectares). The dry solids of peat are estimated at 6.3 billion tones. Sphagnum peat accounts for 54% and Carex peat for 45% of feasible peat reserves. Peatlands that are technically suitable for the peat industry cover a total area of 1.2 million ha and contain 29.6 billion m3 of peat in situ. Slightly humified peat suitable for horticultural and environmental use totals 5.9 billion m3 in situ. The energy peat reserve is 23.7 billion m3 in situ and its energy content is 12 800 TWh. (orig.)

  19. Distribution of peatlands in Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Rieley, J. [Dept. of Life Science, Nottingham (United Kingdom); Page, S.E. [Leicester Univ. (United Kingdom). Dept. of Zoology; Setiadi, B. [Agency for the Assesment and Application of Technology, Jakarta (Indonesia)

    1996-12-31

    Indonesia contains between 160 and 270 000 km{sup 2} of peatland, mostly in the sub-coastal lowlands of Irian Jaya, Kalimantan and Sumatra; depth varies from 0.5 to more than 10 metres. Present day peat started to accumulate in response to very wet climatic conditions after the end of the last glacial period on waterlogged substrates of low nutrient status and oxygen deficiency. Coastal and basin peatlands were preceded by mangrove swamp; Yiigh peat (peat at a slightly higher elevation) was probably initiated in freshwater swamp. Dates of origin range from 800 to almost 5 000 years B.P. for the former and over 9 000 years B.P. for the latter. Lowland tropical peat is relatively homogeneous, consisting of trunks, branches and roots of trees; it is mainly fibric with low mineral content. Peat domes are ombrogenous with a water table close to or above the surface for most of the year. Lowland peat swamps support a zonation of forest types. The marginal, mixed swamp forest is dominated by high canopy trees whilst the interior `pole` forest consists of lower, smaller diameter trees. Indonesian peat swamp forests are an important reservoir of biodiversity; they contain several commercial tree species and provide a range of non-timber forest products. Almost 20 % of the peat swamp forests of Indonesia have been developed for agriculture and settlement. In their natural condition, however, they act as important water catchment and control systems, stabilize the landscape against erosion and maintain water quality for downstream riverine, estuarine and coastal fisheries. (orig.) (19 refs.)

  20. Direct human impacts on the peatland carbon sink

    Science.gov (United States)

    Jukka Laine; Kari Minkkinen; Carl Trettin

    2009-01-01

    Northern peatlands occupy over 3 million km2 globally and contain the largest carbon (C) pool (typically >100 kg C m-2) among terrestrial ecosystems. Agriculture, forestry, and peat harvesting are the principal human-induced activities that alter the peatland and hence the distribution and flux of carbon. As a prerequisite to those uses, the peatland is usually...

  1. After ecological restoration of ombrotrophic peatlands: the microbiological viewpoint; Suivi de la restauration ecologique des tourbieres ombrotrophes: le point de vue microbiologique

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, R. [University of Laval, Quebec, QC (Canada). Department of Phytology

    2006-01-01

    The goal is to assess peatland restoration at an 11-hectare peatland site at Bois-en-Bel that had been abandoned for 20 years. In 1999, an 8-hectare area was restored. Two hectares, separated by a buffer, were left untreated as a control. In 2003, samples were collected from the restored and control areas and from a nearby natural area. The dynamics of carbon and nitrogen, the effects of nutritive supplements, and production of carbon dioxide and methane were measured. The relationship between these variables and the microorganisms present are evaluated. 30 refs., 4 figs.

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

    Science.gov (United States)

    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

  3. Introducing a boreal wetland model within the Earth System model framework

    Science.gov (United States)

    Getzieh, R. J.; Brovkin, V.; Reick, C.; Kleinen, T.; Raddatz, T.; Raivonen, M.; Sevanto, S.

    2009-04-01

    Wetlands of the northern high latitudes with their low temperatures and waterlogged conditions are prerequisite for peat accumulation. They store at least 25% of the global soil organic carbon and constitute currently the largest natural source of methane. These boreal and subarctic peat carbon pools are sensitive to climate change since the ratio of carbon sequestration and emission is closely dependent on hydrology and temperature. Global biogeochemistry models used for simulations of CO2 dynamics in the past and future climates usually ignore changes in the peat storages. Our approach aims at the evaluation of the boreal wetland feedback to climate through the CO2 and CH4 fluxes on decadal to millennial time scales. A generic model of organic matter accumulation and decay in boreal wetlands is under development in the MPI for Meteorology in cooperation with the University of Helsinki. Our approach is to develop a wetland model which is consistent with the physical and biogeochemical components of the land surface module JSBACH as a part of the Earth System model framework ECHAM5-MPIOM-JSBACH. As prototypes, we use modelling approach by Frolking et al. (2001) for the peat dynamics and the wetland model by Wania (2007) for vegetation cover and plant productivity. An initial distribution of wetlands follows the GLWD-3 map by Lehner and Döll (2004). First results of the modelling approach will be presented. References: Frolking, S. E., N. T. Roulet, T. R. Moore, P. J. H. Richard, M. Lavoie and S. D. Muller (2001): Modeling Northern Peatland Decomposition and Peat Accumulation, Ecosystems, 4, 479-498. Lehner, B., Döll P. (2004): Development and validation of a global database of lakes, reservoirs and wetlands. Journal of Hydrology 296 (1-4), 1-22. Wania, R. (2007): Modelling northern peatland land surface processes, vegetation dynamics and methane emissions. PhD thesis, University of Bristol, 122 pp.

  4. Subsidence in tropical peatlands: Estimating CO2 fluxes from peatlands in Southeast Asia

    Science.gov (United States)

    Hoyt, A.; Harvey, C. F.; Seppalainen, S. S.; Chaussard, E.

    2017-12-01

    Tropical peatlands of Southeast Asia are an important global carbon stock. However, they are being rapidly deforested and drained. Peatland drainage facilitates peat decomposition, releases sequestered peat carbon to the atmosphere as CO2, and leads to subsidence of the peat surface. As a result, subsidence measurements can be used to monitor peatland carbon loss over time. Until now, subsidence measurements have been primarily limited to ground-based point measurements using subsidence poles. Here we demonstrate a powerful method to measure peatland subsidence rates across much larger areas than ever before. Using remotely sensed InSAR data, we map subsidence rates across thousands of square kilometers in Southeast Asia and validate our results against ground-based subsidence measurements. The method allows us to monitor subsidence in remote locations, providing unprecedented spatial information, and the first comprehensive survey of land uses such as degraded peatlands, burnt and open areas, shrub lands, and smallholder farmlands. Strong spatial patterns emerged, with the highest subsidence rates occurring at the centers of peat domes, where the peat is thickest and drainage depths are likely to be largest. Peatland subsidence rates were also strongly dependent on current and historical land use, with typical subsidence rates ranging from 2-4 cm/yr. Finally, we scaled up our results to calculate total annual emissions from peat decomposition in degraded peatlands.

  5. Accumulation of organic carbon over the past 150 years in five freshwater peatlands in western and central Europe

    International Nuclear Information System (INIS)

    Novak, Martin; Brizova, Eva; Adamova, Marie; Erbanova, Lucie; Bottrell, Simon H.

    2008-01-01

    Under predicted scenarios of global climate change, peatlands may become a net source of greenhouse gases which will accelerate warming of the atmosphere. Comparative studies of peat bogs along present climatic gradients may provide an insight into the future response of boreal and subarctic peatlands to changing temperature and moisture. Three maritime peat bogs in the British Isles, and two high-elevation peatlands in the Czech Republic were studied. All sites were relatively wet, the mean annual temperatures were higher by up to 6 o C at the British/Irish sites than at the Czech sites. Cumulative carbon content in 210 Pb-dated Sphagnum-dominated vertical peat cores increased from the warmer to the colder sites when evaluated for the most recent decades (since ca. 1950). That would correspond to formation of thinner, more highly decomposed peat deposits over the long-term in warmer conditions, and deeper peat bogs in colder conditions. However, when cumulative carbon content was evaluated for the last ca. 150 years, no relationship was found between mean annual temperature and the carbon pool size. Even along broad present-day climatic gradients, site-specific factors controlled organic carbon preservation in peat. Pollen analysis was instrumental in corroborating the 210 Pb dates, identifying wet and dry periods in the past, and it also provided evidence for increasing nitrogen loads in wetland areas

  6. Modelling wetland-groundwater interactions in the boreal Kälväsvaara esker, Northern Finland

    Science.gov (United States)

    Jaros, Anna; Rossi, Pekka; Ronkanen, Anna-Kaisa; Kløve, Bjørn

    2016-04-01

    Many types of boreal peatland ecosystems such as alkaline fens, aapa mires and Fennoscandia spring fens rely on the presence of groundwater. In these ecosystems groundwater creates unique conditions for flora and fauna by providing water, nutrients and constant water temperature enriching local biodiversity. The groundwater-peatland interactions and their dynamics are not, however, in many cases fully understood and their measurement and quantification is difficult due to highly heterogeneous structure of peatlands and large spatial extend of these ecosystems. Understanding of these interactions and their changes due to anthropogenic impact on groundwater resources would benefit the protection of the groundwater dependent peatlands. The groundwater-peatland interactions were investigated using the fully-integrated physically-based groundwater-surface water code HydroGeoSphere in a case study of the Kälväsvaara esker aquifer, Northern Finland. The Kälväsvaara is a geologically complex esker and it is surrounded by vast aapa mire system including alkaline and springs fens. In addition, numerous small springs occur in the discharge zone of the esker. In order to quantify groundwater-peatland interactions a simple steady-state model was built and results were evaluated using expected trends and field measurements. The employed model reproduced relatively well spatially distributed hydrological variables such as soil water content, water depths and groundwater-surface water exchange fluxes within the wetland and esker areas. The wetlands emerged in simulations as a result of geological and topographical conditions. They could be identified by high saturation levels at ground surface and by presence of shallow ponded water over some areas. The model outputs exhibited also strong surface water-groundwater interactions in some parts of the aapa system. These areas were noted to be regions of substantial diffusive groundwater discharge by the earlier studies. In

  7. Multiyear greenhouse gas balances at a rewetted temperate peatland.

    Science.gov (United States)

    Wilson, David; Farrell, Catherine A; Fallon, David; Moser, Gerald; Müller, Christoph; Renou-Wilson, Florence

    2016-12-01

    Drained peat soils are a significant source of greenhouse gas (GHG) emissions to the atmosphere. Rewetting these soils is considered an important climate change mitigation tool to reduce emissions and create suitable conditions for carbon sequestration. Long-term monitoring is essential to capture interannual variations in GHG emissions and associated environmental variables and to reduce the uncertainty linked with GHG emission factor calculations. In this study, we present GHG balances: carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) calculated for a 5-year period at a rewetted industrial cutaway peatland in Ireland (rewetted 7 years prior to the start of the study); and compare the results with an adjacent drained area (2-year data set), and with ten long-term data sets from intact (i.e. undrained) peatlands in temperate and boreal regions. In the rewetted site, CO 2 exchange (or net ecosystem exchange (NEE)) was strongly influenced by ecosystem respiration (R eco ) rather than gross primary production (GPP). CH 4 emissions were related to soil temperature and either water table level or plant biomass. N 2 O emissions were not detected in either drained or rewetted sites. Rewetting reduced CO 2 emissions in unvegetated areas by approximately 50%. When upscaled to the ecosystem level, the emission factors (calculated as 5-year mean of annual balances) for the rewetted site were (±SD) -104 ± 80 g CO 2 -C m -2  yr -1 (i.e. CO 2 sink) and 9 ± 2 g CH 4 -C m -2  yr -1 (i.e. CH 4 source). Nearly a decade after rewetting, the GHG balance (100-year global warming potential) had reduced noticeably (i.e. less warming) in comparison with the drained site but was still higher than comparative intact sites. Our results indicate that rewetted sites may be more sensitive to interannual changes in weather conditions than their more resilient intact counterparts and may switch from an annual CO 2 sink to a source if triggered by slightly drier

  8. Oil sands mining and reclamation cause massive loss of peatland and stored carbon

    Science.gov (United States)

    Rooney, Rebecca C.; Bayley, Suzanne E.; Schindler, David W.

    2012-01-01

    We quantified the wholesale transformation of the boreal landscape by open-pit oil sands mining in Alberta, Canada to evaluate its effect on carbon storage and sequestration. Contrary to claims made in the media, peatland destroyed by open-pit mining will not be restored. Current plans dictate its replacement with upland forest and tailings storage lakes, amounting to the destruction of over 29,500 ha of peatland habitat. Landscape changes caused by currently approved mines will release between 11.4 and 47.3 million metric tons of stored carbon and will reduce carbon sequestration potential by 5,734–7,241 metric tons C/y. These losses have not previously been quantified, and should be included with the already high estimates of carbon emissions from oil sands mining and bitumen upgrading. A fair evaluation of the costs and benefits of oil sands mining requires a rigorous assessment of impacts on natural capital and ecosystem services. PMID:22411786

  9. Spatially explicit simulation of peatland hydrology and carbon dioxide exchange: Influence of mesoscale topography

    Science.gov (United States)

    Sonnentag, O.; Chen, J. M.; Roulet, N. T.; Ju, W.; Govind, A.

    2008-06-01

    Carbon dynamics in peatlands are controlled, in large part, by their wetness as defined by water table depth and volumetric liquid soil moisture content. A common type of peatland is raised bogs that typically have a multiple-layer canopy of vascular plants over a Sphagnum moss ground cover. Their convex form restricts water supply to precipitation and water is shed toward the margins, usually by lateral subsurface flow. The hydraulic gradient for lateral subsurface flow is governed by the peat surface topography at the mesoscale (˜200 m to 5 km). To investigate the influence of mesoscale topography on wetness, evapotranspiration (ET), and gross primary productivity (GPP) in a bog during the snow-free period, we compare the outputs of a further developed version of the daily Boreal Ecosystem Productivity Simulator (BEPS) with observations made at the Mer Bleue peatland, located near Ottawa, Canada. Explicitly considering mesoscale topography, simulated total ET and GPP correlate well with measured ET (r = 0.91) and derived gross ecosystem productivity (GEP; r = 0.92). Both measured ET and derived GEP are simulated similarly well when mesoscale topography is neglected, but daily simulated values are systematically underestimated by about 10% and 12% on average, respectively, due to greater wetness resulting from the lack of lateral subsurface flow. Owing to the differences in moss surface conductances of water vapor and carbon dioxide with increasing moss water content, the differences in the spatial patterns of simulated total ET and GPP are controlled by the mesotopographic position of the moss ground cover.

  10. Boreal mire Green House Gas exchange in response to global change perturbations

    Science.gov (United States)

    Nilsson, Mats

    2017-04-01

    High latitude boreal peatlands contribute importantly to the land-atmosphere-hydrosphere exchange of carbon and GHG, i.e. carbon dioxide, methane and dissolved organic carbon. High latitude biomes are identified as most vulnerable to changing climate. High latitudes are also characterized by a strong seasonality in incoming solar radiation, weather conditions and thus also in biogeochemical processes. The strong seasonality in incoming solar radiation, not to change in response to a changing climate, constitute firm constraints on how changes in air temperature, evapotranspiration and precipitation will affect biogeochemical processes underlying the land atmosphere and land hydrosphere exchange of green house gases. In this presentation I combine data from long-term monitoring, long-term field manipulations and detailed chemical analysis to understand how changes in atmosphere and weather conditions influence the major carbon fluxes of a boreal mire Net Ecosystem Carbon Balance. The long-term monitoring data contains >12 years of continuous Eddy Covariance CO2 data, growing season chamber CH4 data and continuous measurements of discharge export of DOC, CO2 and CH4. Data from long-term field snow removal manipulations and growing season temperature increase manipulations are used to further understand the impact of climate on mire carbon and GHG fluxes. Finally we uses Nuclear Magnetic Spectroscopy (NMR) to reveal how century scale changes in atmospheric CO2 from 300 to 400 pm CO2 and temperature have influenced the net photosynthetic capacity of Sphagnum mosses, the single most important plant genus for boreal mire carbon sequestration.

  11. Buffer Zone Fact Sheets

    Science.gov (United States)

    New requirements for buffer zones and sign posting contribute to soil fumigant mitigation and protection for workers and bystanders. The buffer provides distance between the pesticide application site and bystanders, reducing exposure risk.

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

    Science.gov (United States)

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

    2015-12-01

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

  13. Increased losses of organic carbon and destabilising of tropical peatlands following deforestation, drainage and burning. (Invited)

    Science.gov (United States)

    Moore, S.; Gauci, V.; Evans, C.; Page, S. E.

    2013-12-01

    Tropical peatlands contain one of the largest pools of terrestrial organic carbon, amounting to about 89,000 teragrams. Approximately 65% of this carbon store is in Indonesia, where extensive anthropogenic degradation in the form of deforestation, drainage and associated fire is converting it into a globally significant source of atmospheric carbon dioxide. Unlike boreal and temperate forests and higher-latitude wetlands, however, the loss of fluvial organic carbon from tropical peats has yet to be fully quantified. Here, we present the first data from intact and degraded peat swamp forest (PSF) catchments in Central Kalimantan, Borneo, that indicate a doubling of fluvial organic carbon losses from tropical peatlands following deforestation and drainage. Through carbon-14 dating of dissolved organic carbon (DO14C), we find that leaching of DOC from intact PSF is derived mainly from recent primary production. In contrast, DOC from disturbed PSF consists mostly of much older carbon from deep within the peat column. When we include this fluvial carbon loss, which is often ignored in peatland carbon budgets, we find that it increases the estimate of total carbon lost from the disturbed peatlands in our study by 22%. We further estimate that since 1990, peatland disturbance has resulted in a 32% increase in fluvial organic carbon flux from Southeast Asia - an increase that equates to more than half of the entire annual fluvial organic carbon flux from all European peatlands. Finally, we monitored fluvial organic carbon fluxes following large-scale peatland fires in 2009/10 within the study sub-catchments and found fluvial carbon fluxes to be 30-70% larger in the fire-affected catchments when compared to fluxes during the same interval in the previous year (pre-fire). This is in marked contrast to the intact catchment (control/no fire) where there were no differences observed in fluxes 'pre to post fire years'. Our sub-catchment findings were also found to be

  14. Ecological Sustainability of Birds in Boreal Forests

    Directory of Open Access Journals (Sweden)

    Gerald Niemi

    1998-12-01

    Full Text Available We review characteristics of birds in boreal forests in the context of their ecological sustainability under both natural and anthropogenic disturbances. We identify the underlying ecological factors associated with boreal bird populations and their variability, review the interactions between boreal bird populations and disturbance, and describe some tools on how boreal bird populations may be conserved in the future. The boreal system has historically been an area with extensive disturbance such as fire, insect outbreaks, and wind. In addition, the boreal system is vulnerable to global climate change as well as increasing pressure on forest and water resources. Current knowledge indicates that birds play an important role in boreal forests, and sustaining these populations affords many benefits to the health of boreal forests. Many issues must be approached with caution, including the lack of knowledge on our ability to mimic natural disturbance regimes with management, our lack of understanding on fragmentation due to logging activity, which is different from permanent conversion to other land uses such as agriculture or residential area, and our lack of knowledge on what controls variability in boreal bird populations or the linkage between bird population fluctuations and productivity. The essential role that birds can provide is to clarify important ecological concerns and variables that not only will help to sustain bird populations, but also will contribute to the long-term health of the boreal forest for all species, including humans.

  15. Managing peatland vegetation for drinking water treatment.

    Science.gov (United States)

    Ritson, Jonathan P; Bell, Michael; Brazier, Richard E; Grand-Clement, Emilie; Graham, Nigel J D; Freeman, Chris; Smith, David; Templeton, Michael R; Clark, Joanna M

    2016-11-18

    Peatland ecosystem services include drinking water provision, flood mitigation, habitat provision and carbon sequestration. Dissolved organic carbon (DOC) removal is a key treatment process for the supply of potable water downstream from peat-dominated catchments. A transition from peat-forming Sphagnum moss to vascular plants has been observed in peatlands degraded by (a) land management, (b) atmospheric deposition and (c) climate change. Here within we show that the presence of vascular plants with higher annual above-ground biomass production leads to a seasonal addition of labile plant material into the peatland ecosystem as litter recalcitrance is lower. The net effect will be a smaller litter carbon pool due to higher rates of decomposition, and a greater seasonal pattern of DOC flux. Conventional water treatment involving coagulation-flocculation-sedimentation may be impeded by vascular plant-derived DOC. It has been shown that vascular plant-derived DOC is more difficult to remove via these methods than DOC derived from Sphagnum, whilst also being less susceptible to microbial mineralisation before reaching the treatment works. These results provide evidence that practices aimed at re-establishing Sphagnum moss on degraded peatlands could reduce costs and improve efficacy at water treatment works, offering an alternative to 'end-of-pipe' solutions through management of ecosystem service provision.

  16. Stability of peatland carbon to rising temperatures

    Science.gov (United States)

    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,...

  17. Nitrogen dynamics in northern peatland ecosystems

    Science.gov (United States)

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

  18. Black (pyrogenic carbon: a synthesis of current knowledge and uncertainties with special consideration of boreal regions

    Directory of Open Access Journals (Sweden)

    C. M. Preston

    2006-01-01

    Full Text Available The carbon (C cycle in boreal regions is strongly influenced by fire, which converts biomass and detrital C mainly to gaseous forms (CO2 and smaller proportions of CO and CH4, and some 1–3% of mass to pyrogenic C (PyC. PyC is mainly produced as solid charred residues, including visually-defined charcoal, and a black carbon (BC fraction chemically defined by its resistance to laboratory oxidation, plus much lower proportions of volatile soot and polycyclic aromatic hydrocarbons (PAHs. All PyC is characterized by fused aromatic rings, but varying in cluster sizes, and presence of other elements (N, O and functional groups. The range of PyC structures is often described as a continuum from partially charred plant materials, to charcoal, soot and ultimately graphite which is formed by the combination of heat and pressure. There are several reasons for current interest in defining more precisely the role of PyC in the C cycle of boreal regions. First, PyC is largely resistant to decomposition, and therefore contributes to very stable C pools in soils and sediments. Second, it influences soil processes, mainly through its sorption properties and cation exchange capacity, and third, soot aerosols absorb solar radiation and may contribute to global warming. However, there are large gaps in the basic information needed to address these topics. While charcoal is commonly defined by visual criteria, analytical methods for BC are mainly based on various measures of oxidation resistance, or on yield of benzenepolycarboxylic acids. These methods are still being developed, and capture different fractions of the PyC structural continuum. There are few quantitative reports of PyC production and stocks in boreal forests (essentially none for boreal peatlands, and results are difficult to compare due to varying experimental goals and methods, as well as inconsistent terminology. There are almost no direct field measurements of BC aerosol production from boreal

  19. The Role of Low-severity Fire and Thermal Alteration of Soil Organic Matter in Carbon Preservation and GHG Flux From Global Peatlands

    Science.gov (United States)

    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

  20. Do we miss the hot spots? – The use of very high resolution aerial photographs to quantify carbon fluxes in peatlands

    Directory of Open Access Journals (Sweden)

    T. Becker

    2008-10-01

    Full Text Available Accurate determination of carbon balances in heterogeneous ecosystems often requires the extrapolation of point based measurements. The ground resolution (pixel size of the extrapolation base, e.g. a land-cover map, might thus influence the calculated carbon balance, in particular if biogeochemical hot spots are small in size. In this paper, we test the effects of varying ground resolution on the calculated carbon balance of a boreal peatland consisting of hummocks (dry, lawns (intermediate and flarks (wet surfaces. The generalizations in lower resolution imagery led to biased area estimates for individual micro-site types. While areas of lawns and hummocks were stable below a threshold resolution of ~60 cm, the maximum of the flark area was located at resolutions below 25 cm and was then decreasing with coarsening resolution. Using a resolution of 100 cm instead of 6 cm led to an overestimation of total CO2 uptake of the studied peatland area (approximately 14 600 m2 of ~5% and an underestimation of total CH4 emission of ~6%. To accurately determine the surface area of scattered and small-sized micro-site types in heterogeneous ecosystems (e.g. flarks in peatlands, a minimum ground resolution appears necessary. In our case this leads to a recommended resolution of 25 cm, which can be derived by conventional airborne imagery. The usage of high resolution imagery from commercial satellites, e.g. Quickbird, however, is likely to underestimate the surface area of biogeochemical hot spots. It is important to note that the observed resolution effect on the carbon balance estimates can be much stronger for other ecosystems than for the investigated peatland. In the investigated peatland the relative hot spot area of the flarks is very small and their hot spot characteristics with respect to CH4 and CO2 fluxes is rather modest.

  1. Carbon sequestration from boreal wildfires via Pyrogenic Carbon production

    Science.gov (United States)

    Santin, Cristina; Doerr, Stefan; Preston, Caroline

    2014-05-01

    Fire releases important quantities of carbon (C) to the atmosphere. Every year, an average of 460 Million ha burn around the globe, generating C emissions equivalent to a third of the current annual contribution from fossil fuel combustion. Over the longer-term wildfires are widely considered as 'net zero C emission events', because C emissions from fires, excluding those associated with deforestation and peatland fires, are balanced by C uptake by regenerating vegetation. This 'zero C emission' scenario, however, may be flawed, as it does not consider the production of pyrogenic C (PyC). During fire, part of the biomass C burnt is emitted to the atmosphere but part is transformed into PyC (i.e. charcoal). The enhanced resistance of PyC to environmental degradation compared to unburnt biomass gives it the potential to sequester C over the medium/long term. Therefore, after complete regeneration of the vegetation, the PyC generated may represent an additional C pool and, hence, recurring fire-regrowth cycles could represent net sinks of atmospheric C. To estimate the quantitative importance of PyC production, accurate data on PyC generation with respect to the fuel combusted are needed. Unfortunately, detailed quantification of fuel prior to fire is normally only available for prescribed and experimental fires, which are usually of low-intensity and therefore not representative of higher-intensity wildfires. Furthermore, what little data is available is usually based on only a specific fraction of the PyC present following burning rather than the whole range of PyC products and pools (i.e. PyC in soil, ash, downed wood and standing vegetation). To address this research gap, we utilized the globally unique FireSmart experimental forest fires in Northwest Canada. They are aimed to reproduce wildfire conditions typical for boreal forest and, at the same time, allow pre-fire fuel assessment, fire behaviour monitoring and immediate post-fire fuel and PyC inventory. This

  2. Emissions of methane and nitrogen oxides from peatland ecosystems

    International Nuclear Information System (INIS)

    Martikainen, P.J.; Nykaenen, H.; Laang, K.; Alm, J.; Silvola, J.

    1994-01-01

    Climatic change may cause drier, warmer summer in the high latitudes and cause remarkable changes in gas fluxes on peatlands. Drained peatlands can be used as models to predict the long-term effects of increased peat aeration on trace gas fluxes. Results are presented from studies about emissions of CH 4 , N 2 O and NO in both virgin and drained Finnish peatlands, and give some information about the factors regulating the production and consumption of these trace gases

  3. Wetland restoration: a survey of options for restoring peatlands

    International Nuclear Information System (INIS)

    Lode, Elve

    1999-01-01

    In spite of increased attention to wetland conservation following the Ramsar Convention on Wetlands of International Importance, the peat-harvesting industry in many countries is still interested in the further exploitation of peatlands. In some of the most industrialised countries, all natural peatlands have already been lost. In others, only small areas of native peatland remain. Among other possible uses for cut-over peatlands, peatland restoration is one: there is an urgent need for the development of measures for regenerating peat-accumulation processes. The redevelopment of a fen or bog peat landscape is a long-term process, which will probably take centuries. The restoration of any peatland may therefore be considered successful if the outcome is the development and growth of plant communities able to produce peat. The renewal of the hydrological regime of such areas is a major factor which determines the re-colonisation of cut-over peat fields by peat-forming plants. The aim of this paper is to give a brief survey of wetlands, and especially of peatland restoration options, for use in terminated peat-cuttings. It aims to show how peatland management may be made sustainable by means of existing and tried methods and principles, with the goal of returning cut-over peat fields to their former peat-accumulating state. A glossary of peat and peatland terminology is included 105 refs, 5 figs

  4. Carbon dynamics and ecosystem diversity of Amazonian peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Laehteenoja, O.

    2011-07-01

    The overall aim was to initiate peatland research in Amazonia, which has been referred to as 'one of the large white spots on the global peatland map'. Specifically, the study was to clarify how common peat accumulation is on Amazonian floodplains, and how extensive and thick peat deposits can be encountered. Secondly, the intention was to study how rapidly Amazonian peatlands sequester carbon, and how much carbon they store and thirdly, to gain some understanding of the diversity of peatland ecosystem types and of the processes forming these ecosystems

  5. Redox Buffer Strength

    Science.gov (United States)

    de Levie, Robert

    1999-04-01

    The proper functioning of enzymes in bodily fluids requires that the pH be maintained within rather narrow limits. The first line of defense against large pH fluctuations in such fluids is the passive control provided by the presence of pH buffers. The ability of pH buffers to stabilize the pH is indicated by the buffer value b introduced in 1922 by van Slyke. It is equally important for many enzymes that the redox potential is kept within a narrow range. In that case, stability of the potential is most readily achieved with a redox buffer. In this communication we define the redox buffer strength by analogy with acid-base buffer strength.

  6. Organellar Calcium Buffers

    Science.gov (United States)

    Prins, Daniel; Michalak, Marek

    2011-01-01

    Ca2+ is an important intracellular messenger affecting many diverse processes. In eukaryotic cells, Ca2+ storage is achieved within specific intracellular organelles, especially the endoplasmic/sarcoplasmic reticulum, in which Ca2+ is buffered by specific proteins known as Ca2+ buffers. Ca2+ buffers are a diverse group of proteins, varying in their affinities and capacities for Ca2+, but they typically also carry out other functions within the cell. The wide range of organelles containing Ca2+ and the evidence supporting cross-talk between these organelles suggest the existence of a dynamic network of organellar Ca2+ signaling, mediated by a variety of organellar Ca2+ buffers. PMID:21421925

  7. Lateral extension in Sphagnum mires along the southern margin of the boreal region, Western Siberia

    International Nuclear Information System (INIS)

    Peregon, A; Uchida, M; Yamagata, Y

    2009-01-01

    Although recent studies have recognized Northern Eurasian ecosystems as an important carbon reservoir, little is known about the forest-peatland interactions in a boreal environment induced by ongoing climatic changes. This study focuses on the evaluation of both the long-term and contemporary trends of land-cover changes and rates of lateral extension of peat-accumulating wetlands toward the adjacent forests, estimated at the southern climatic range of the Sphagnum-dominated mires in Western Siberia. We used the radiocarbon dates and stratigraphy of peat sediments from seven peat cores, analyzed at two types of forest-peatland ecotones, which are located close to each other but differ by topography and composition of their plant communities. The rate of lateral extension was found in a wide range varying from 2.3 to 791.7 cm yr -1 . It was observed to be rapid during the initial stage of mire development, but to have slowed down over the last 2000-3000 yr. Our results, therefore, strongly contradict the concept of progressive peat accumulation throughout the late Holocene and contribute to our knowledge about ongoing land-cover change in the natural ecosystems of the Northern hemisphere.

  8. Lateral extension in Sphagnum mires along the southern margin of the boreal region, Western Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Peregon, A; Uchida, M; Yamagata, Y, E-mail: anna.peregon@nies.go.j [Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan)

    2009-10-15

    Although recent studies have recognized Northern Eurasian ecosystems as an important carbon reservoir, little is known about the forest-peatland interactions in a boreal environment induced by ongoing climatic changes. This study focuses on the evaluation of both the long-term and contemporary trends of land-cover changes and rates of lateral extension of peat-accumulating wetlands toward the adjacent forests, estimated at the southern climatic range of the Sphagnum-dominated mires in Western Siberia. We used the radiocarbon dates and stratigraphy of peat sediments from seven peat cores, analyzed at two types of forest-peatland ecotones, which are located close to each other but differ by topography and composition of their plant communities. The rate of lateral extension was found in a wide range varying from 2.3 to 791.7 cm yr{sup -1}. It was observed to be rapid during the initial stage of mire development, but to have slowed down over the last 2000-3000 yr. Our results, therefore, strongly contradict the concept of progressive peat accumulation throughout the late Holocene and contribute to our knowledge about ongoing land-cover change in the natural ecosystems of the Northern hemisphere.

  9. Responses of non-methane biogenic volatile organic compound emissions to climate change in boreal and subarctic ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Faubert, P.

    2010-07-01

    Non-methane biogenic volatile organic compound emissions (BVOCs) have important roles in the global atmospheric chemistry but their feedbacks to climate change are still unknown. This thesis reports one of the first estimates of BVOC emissions from boreal and subarctic ecosystems. Most importantly, this thesis assesses the BVOC emission responses to four effects of climate change in these ecosystems: (1) the direct effect of warming, and its indirect effects via (2) water table drawdown, (3) change in the vegetation composition, and (4) enhanced UV-B radiation. BVOC emissions were measured using a conventional chamber method in which the compounds were collected on adsorbent and later analyzed by gas chromatography-mass spectrometry. On a subarctic heath, warming by only 1.9-2.5 degC doubled the monoterpene and sesquiterpene emissions. Such a high increase of BVOC emissions under a conservative warming cannot be predicted by the current models, which underlines the importance of a focus on BVOC emissions from the Subarctic under climate change. On a subarctic peatland, enhanced UV-B did not affect the BVOC emissions but the water table level exerted the major effect. The water table drawdown experimentally applied on boreal peatland microcosms decreased the emissions of monoterpenes and other VOCs (BVOCs with a lifetime>1 d) for the hollows (wet microsites) and that of all BVOC groups for the lawns (moderately wet microsites). The warming treatment applied on the lawn microcosms decreased the isoprene emission. The removal of vascular plants in the hummock (dry microsites) microcosms decreased the emissions of monoterpenes while the emissions between the microcosms covered with Sphagnum moss and bare peat were not different. In conclusion, the results presented in this thesis indicate that climate change has complex effects on the BVOC emissions. These results make a significant contribution to improving the modeling of BVOC emissions for a better understanding of

  10. Fine root production at drained peatland sites

    Energy Technology Data Exchange (ETDEWEB)

    Finer, L [Finnish Forest Research Inst. (Finland). Joensuu Research Station; Laine, J [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1997-12-31

    The preliminary results of the Finnish project `Carbon balance of peatlands and climate change` show that fine roots play an important role in carbon cycling on peat soils. After drainage the roots of mire species are gradually replaced by the roots of trees and other forest species. Pine fine root biomass reaches a maximum level by the time of crown closure, some 20 years after drainage on pine mire. The aim of this study is to compare the results of the sequential coring method and the ingrowth bag method used for estimating fine root production on three drained peatland sites of different fertility. The results are preliminary and continuation to the work done in the study Pine root production on drained peatlands, which is part of the Finnish project `Carbon cycling on peatlands and climate change`. In this study the fine root biomass was greater on the poor site than on the rich sites. Pine fine root production increased with the decrease in fertility. Root turnover and the production of field layer species were greater on the rich sites than on the poor site. The results suggested that the in growth bag method measured more root activity than the magnitude of production. More than two growing seasons would have been needed to balance the root dynamics in the in growth bags with the surrounding soil. That time would probably have been longer on the poor site than on the rich ones and longer for pine and field layer consisting of dwarf shrubs than for field layer consisting of sedge like species and birch. (11 refs.)

  11. Fine root production at drained peatland sites

    Energy Technology Data Exchange (ETDEWEB)

    Finer, L. [Finnish Forest Research Inst. (Finland). Joensuu Research Station; Laine, J. [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1996-12-31

    The preliminary results of the Finnish project `Carbon balance of peatlands and climate change` show that fine roots play an important role in carbon cycling on peat soils. After drainage the roots of mire species are gradually replaced by the roots of trees and other forest species. Pine fine root biomass reaches a maximum level by the time of crown closure, some 20 years after drainage on pine mire. The aim of this study is to compare the results of the sequential coring method and the ingrowth bag method used for estimating fine root production on three drained peatland sites of different fertility. The results are preliminary and continuation to the work done in the study Pine root production on drained peatlands, which is part of the Finnish project `Carbon cycling on peatlands and climate change`. In this study the fine root biomass was greater on the poor site than on the rich sites. Pine fine root production increased with the decrease in fertility. Root turnover and the production of field layer species were greater on the rich sites than on the poor site. The results suggested that the in growth bag method measured more root activity than the magnitude of production. More than two growing seasons would have been needed to balance the root dynamics in the in growth bags with the surrounding soil. That time would probably have been longer on the poor site than on the rich ones and longer for pine and field layer consisting of dwarf shrubs than for field layer consisting of sedge like species and birch. (11 refs.)

  12. Silviculture's role in managing boreal forests

    Science.gov (United States)

    Russell T. Graham; Theresa B. Jain

    1998-01-01

    Boreal forests, which are often undeveloped, are a major source of raw materials for many countries. They are circumpolar in extent and occupy a belt to a width of 1000 km in certain regions. Various conifer and hardwood species ranging from true firs to poplars grow in boreal forests. These species exhibit a wide range of shade tolerance and growth characteristics,...

  13. Sequestration of arsenic in ombrotrophic peatlands

    Science.gov (United States)

    Rothwell, James; Hudson-Edwards, Karen; Taylor, Kevin; Polya, David; Evans, Martin; Allott, Tim

    2014-05-01

    Peatlands can be important stores of arsenic but we are lacking spectroscopic evidence of the sequestration pathways of this toxic metalloid in peatland environments. This study reports on the solid-phase speciation of anthropogenically-derived arsenic in atmospherically contaminated peat from the Peak District National Park (UK). Surface and sub-surface peat samples were analysed by synchrotron X-ray absorption spectroscopy on B18 beamline at Diamond Light Source (UK). The results suggest that there are contrasting arsenic sequestration mechanisms in the peat. The bulk arsenic speciation results, in combination with strong arsenic-iron correlations at the surface, suggest that iron (hydr)oxides are key phases for the immobilisation of arsenic at the peat surface. In contrast, the deeper peat samples are dominated by arsenic sulphides (arsenopyrite, realgar and orpiment). Given that these peats receive inputs solely from the atmosphere, the presence of these sulphide phases suggests an in-situ authigenic formation. Redox oscillations in the peat due to a fluctuating water table and an abundant store of legacy sulphur from historic acid rain inputs may favour the precipitation of arsenic sequestering sulphides in sub-surface horizons. Oxidation-induced loss of these arsenic sequestering sulphur species by water table drawdown has important implications for the mobility of arsenic and the quality of waters draining peatlands.

  14. Vegetation, soil property and climatic controls over greenhouse gas fluxes in a blanket peatland hosting a wind farm

    Science.gov (United States)

    Armstrong, Alona; Waldron, Susan; Ostle, Nick; Whitaker, Jeanette

    2013-04-01

    Peatlands are important carbon (C) stores, with boreal and subarctic peatlands containing 15-30 % of the world soil carbon stock (Limpens et al., 2008). Research has demonstrated that greenhouse gas (GHG) fluxes in peatlands are influenced by vegetation, soil property and climatic variables, including plant functional type (PFT), water table height and temperature. In this paper we present data from Black Law Wind Farm, Scotland, where we examined the effect of a predicted wind turbine-induced microclimatic gradient and PFT on carbon dioxide (CO2) and methane (CH4) fluxes. Moreover, we determined the role of vegetation, soil property and climatic variables as predictors of the variation in CO2 and CH4 emissions. We measured CO2 and CH4 at 48 plots within Black Law Wind Farm at monthly intervals from May 2011 to April 2012. Four sampling sites were located along a predicted wind turbine-induced microclimatic gradient. At each site four blocks were established, each with plots in areas dominated by mosses, sedges and shrubs. Plant biomass and PFT (vegetation factors); soil moisture, water table height, peat depth, C content, nitrogen (N) content and C:N (soil properties); and soil temperature and photosynthetically active radiation (PAR) (climatic variables) were measured. Analysis of variance (ANOVA) models based on the microclimatic gradient site, PFT and season when measurements were made explained 58 %, 44 % and 49 % of the variation in ecosystem respiration, photosynthesis and CH4, respectively. Site, PFT, season and their interactions were all significant for respiration and photosynthesis (with the exception of the PFT*site interaction) but for CH4 only the main effects were significant. Parsimonious ANOVA models using the biotic, soil property and climatic explanatory data explained 62 %, 55 % and 49 % of the variation in respiration, photosynthesis and CH4, respectively. Published studies (Baidya Roy and Traiteur 2010; Zhou et al., 2012) and preliminary

  15. Human influences on the health of northern peatlands

    International Nuclear Information System (INIS)

    Gorham, E.

    1991-01-01

    The present area of peat is estimated to be 342 million hectares, with an average depth of 2.3 m. Peatlands are of interest for their flora and fauna, as a habitat for wildlife, for their capacity to moderate stream flows, and for their sequestration of nitrogen and sulfur (elements important in stream and lake acidification). Of great biogeochemical significance is the role of northern peatlands in the global carbon cycle. Their total stock of carbon stored as peat is 455 Pg, or 64% of the amount present as atmospheric CO 2 , 55% of total plant biomass, and 30% of the global pool of soil carbon excluding peat. The rate of peatland sequestration of atmospheric carbon is very small compared to current emissions of 5.6 Pg from fossil fuel combustion. On the other hand, northern peatlands emit ca 0.046 gigatonnes of carbon in the form of methane, which is about 20 times as effective as a greenhouse gas than CO 2 . Human disturbances to peatlands come directly from forestry, agriculture, and fuel/horticultural peat extraction, and indirectly from destruction or utilization of surrounding upland ecosystems, deposition of pollutants, and global warming. Approaches to the study of human impacts on peatlands are outlined and suggestions are offered to guide peatland research. Peatland conservation and restoration are also briefly reviewed. 65 refs

  16. The institutional fit of peatland governance in Indonesia

    NARCIS (Netherlands)

    Uda, Saritha Kittie; Schouten, Greetje; Hein, Lars

    2018-01-01

    The Government of Indonesia has published a number of policies and regulations to better manage its vast amount of tropical peatland, yet the degradation and conversion of Indonesian peatlands still continues. This paper analyses the institutional fit between Indonesian regulations related to

  17. Peatlands: their nature and role in the biosphere

    International Nuclear Information System (INIS)

    Maltby, E.; Proctor, M.C.F.

    1996-01-01

    There are approximately 4 million km 2 of peatlands worldwide, covering some 3 % of the land surface. Their exact extent is uncertain within 150 000 km 2 or so. This is partly because of the difficulty of defining their boundaries precisely, and partly from simple lack of information, especially from parts of Canada and the former USSR, and within the tropical regions. Over 90 % of peatlands are in the temperate and cold belt in the Northern Hemisphere. It is estimated that almost 95 % of peatlands are found in just eight nations: CIS (former USSR) (38 %); Canada (28 %); USA (15 %); Indonesia (6 %); Finland (3 %); Sweden (2 %); China (1 %); Norway (1 %). European peatlands excluding the former USSR amount to just 7 % of the total area. African and South American peatlands each account for 1 % of the total. Central America holds less than 1 % of the global total. Tropical peatlands may account for as much as 10 % of the total area, and more than 7 % of the world total is in south-east Asia alone. The significance of the very large carbon store represented by the world's peatlands in relation to global carbon cycling, and the potential for global environmental change, is becoming increasingly apparent. In this chapter also the conditions for the formation of peat, limits of peat growth, element accumulation, nutrient cycling and budgets of peatlands are discussed. (29 refs.)

  18. Element cycling in upland/peatland watersheds Chapter 8.

    Science.gov (United States)

    Noel Urban; Elon S. Verry; Steven Eisenreich; David F. Grigal; Stephen D. Sebestyen

    2011-01-01

    Studies at the Marcell Experimental Forest (MEF) have measured the pools, cycling, and transport of a variety of elements in both the upland and peatland components of the landscape. Peatlands are important zones of element retention and biogeochemical reactions that greatly influence the chemistry of surface water. In this chapter, we summarize findings on nitrogen (N...

  19. Assessment of chemical properties of tropical peatland soil in ...

    African Journals Online (AJOL)

    The chemical assessment of the peatland in oil palm plantation in South Selangor Peatland Swamp in Malaysia were evaluated in this study. Soil samples were obtained from fifteen (15) different locations within the study area at three different depths of 0.5m, 1.5 m, and 2.5 m in three replicates at each depth, using peat ...

  20. Plant diversity associated with pools in natural and restored peatlands

    Directory of Open Access Journals (Sweden)

    N. Fontaine

    2007-06-01

    Full Text Available This study describes plant assemblages associated with the edges of peatland pools. We conducted inventories in six natural peatlands in the province of Québec (Canada in order to measure the contribution of pools to species diversity in climatic regions where peatlands are used for peat extraction. We also carried out vegetation surveys in a peatland that has been restored after peat extraction/harvesting to determine whether pool vegetation establishes along the edges of created pools when dry surface restoration techniques only are used. Pools enhanced plant species richness in natural peatlands. Around created pools, species associated with natural pools were still absent, and non-bog species were present, six years after restoration. On this basis, we emphasise the importance of preserving natural peatlands with pools. In order to restore fully the plant diversity associated with peatlands at harvested sites, it may be necessary to modify pool excavation techniques so that created pools resemble more closely those in natural peatlands. Active introduction of the plant species or communities associated with natural pools may also be needed; candidate species for North America include Andromeda glaucophylla, Cladopodiella fluitans, Carex limosa, Eriophorum virginicum, Rhynchospora alba and Sphagnum cuspidatum.

  1. Inventory and monitoring options of peatlands at regional scale

    DEFF Research Database (Denmark)

    Gardi, Ciro; Sommer, Stefan; Seep, Kalev

    2010-01-01

    Determination of the spatial extent of peatlands and monitoring their status is important for the evaluation of soil carbon stocks and greenhouse gas fluxes. At European Level there is a need to provide accurate and updated estimate of the distribution of peatlands. Comparison of national data wi...

  2. Peatlands and carbon flows. Outlook and importance for the Netherlands

    International Nuclear Information System (INIS)

    Verhagen, A.; Van den Akker, J.J.H.; Diemont, W.H.; Schrijver, R.A.M.; Wosten, H.M.; Blok, C.; Joosten, J.H.J.; Schouten, M.A.; Den Uyl, R.M.; Verweij, P.A.

    2010-02-01

    Peatlands are found on all continents, however, uncertainties regarding their size and exact locations are very high. Horticulture is the main user of peat in the Netherlands. Compared to other terrestrial ecosystems, peatlands are the most space-effective carbon stocks. Annual emissions of carbon dioxide from peat import for Dutch horticulture is between 0.2 and 0.3 Mt. Climate change will considerably increase most problems associated with peat soils in the Netherlands. It is difficult to establish a correlation between economic activities within the Netherlands and exploitation of tropical peatland. Of the products imported into the Netherlands palm oil perhaps is the most threatening to tropical peatlands. Given the increasing demand from, for example, India and China, the main challenge is to meet this demand without clearing forests, reclaiming peatland, or exploiting other carbon stocks.

  3. How important are peatlands globally in providing drinking water resources?

    Science.gov (United States)

    Xu, Jiren; Morris, Paul; Holden, Joseph

    2017-04-01

    The potential role of peatlands as water stores and sources of downstream water resources for human use is often cited in publications setting the context for the importance of peatlands, but is rarely backed up with substantive evidence. We sought to determine the global role of peatlands in water resource provision. We developed the Peat Population Index (PPI) that combines the coverage of peat and the local population density to show focused (hotspot) areas where there is a combination of both large areas of peat and large populations who would potentially use water sourced from those peatlands. We also developed a method for estimating the proportion of river water that interacted with contributing peatlands before draining into rivers and reservoirs used as a drinking water resource. The Peat Reservoir Index (PRI) estimates the contribution of peatlands to domestic water use to be 1.64 km3 per year which is 0.35 % of the global total. The results suggest that although peatlands are widespread, the spatial distribution of the high PPI and PRI river basins is concentrated in European middle latitudes particularly around major conurbations in The Netherlands, northern England, Scotland (Glasgow) and Ireland (Dublin), although there were also some important systems in Florida, the Niger Delta and Malaysia. More detailed research into water resource provision in high PPI areas showed that they were not always also high PRI areas as often water resources were delivered to urban centres from non-peat areas, despite a large area of peat within the catchment. However, particularly in the UK and Ireland, there are some high PRI systems where peatlands directly supply water to nearby urban centres. Thus both indices are useful and can be used at a global level while more local refinement enables enhanced use which supports global and local peatland protection measures. We now intend to study the impacts of peatland degradation and climate change on water resource

  4. Threats to intact tropical peatlands and opportunities for their conservation.

    Science.gov (United States)

    Roucoux, K H; Lawson, I T; Baker, T R; Del Castillo Torres, D; Draper, F C; Lähteenoja, O; Gilmore, M P; Honorio Coronado, E N; Kelly, T J; Mitchard, E T A; Vriesendorp, C F

    2017-12-01

    Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza-Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land-use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon-dense (domed pole forest) areas. New carbon-based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development. © 2017 The Authors. Conservation Biology published by Wiley Periodicals, Inc

  5. Microbial metabolic potential for carbon degradation and nutrient (nitrogen and phosphorus) acquisition in an ombrotrophic peatland.

    Science.gov (United States)

    Lin, Xueju; Tfaily, Malak M; Green, Stefan J; Steinweg, J Megan; Chanton, Patrick; Imvittaya, Aopeau; Chanton, Jeffrey P; Cooper, William; Schadt, Christopher; Kostka, Joel E

    2014-06-01

    oligosaccharide degradation at MEF relative to other wetland and soil environments, consistent with the nutrient-poor and carbohydrate-rich conditions found in this Sphagnum-dominated boreal peatland.

  6. Uncertainty of Methane Fluxes in a Northern Peatland under Global Climate Change

    Science.gov (United States)

    MA, S.; Jiang, J.; Huang, Y.; Luo, Y.

    2016-12-01

    Large uncertainty exists in predicting responses of methane fluxes to future climate change. How the uncertainty is related to methane production, oxidation, diffusion, ebullition and plant mediated transportation is still poorly understood, despite of the fact that these processes related to methane emission have been theoretically well represented. At the same time, in methane models many of the parameters are given to an empirical value according to measurements or models decades ago. It is unrealistic to testify all the parameters included in methane modules by actual in situ measurements due to the fact of high temporal and spatial variation. However it would be convincible and feasible to measure in field if models could offer better sampling strategy by telling which parameter is more important for estimation of methane emission, and project a constrained value for key parameters in each process. These feedbacks from field measurements could in turn testify the model accuracy for methane emission projection, as well as the optimization of model structures. We incorporated methane module into an existing process-based Terrestrial ECOsystem model (TECO), to simulate methane emission in a boreal peatland forest, northern Minnesota (Spruce and Peatland Responses Under Climatic and Environmental Change Experiment, SPRUCE). We performed sensitivity test and picked key parameters from the five processes for data assimilation using the Bayesian probability inversion and a Markov Chain Monte Carlo (MCMC) technique. We were able to constrain key parameters related to the five processes in the TECO-SPRUCE Methane model. The constrained model simulated daily methane emission fitted quite well with the data from field measurements. The improvement of more realistic and site-specific parameter values allow for reasonable projections of methane emission under different global changing scenarios, warming and elevated CO2, for instance, given the fact that methane emission

  7. Design, construction and performance of an experimental watershed to support a fen peatland for mine landscape reclamation

    Science.gov (United States)

    Price, J. S.; Petrone, R. M.; Strack, M.; Cooper, D. J.

    2017-12-01

    In the Alberta oil sands region, fen peatlands comprised 50% of the boreal landscape. Oil sands mining has stripped over 800 km2 of land surface to access bitumen, necessitating landscape reclamation to re-establish functional wetlands. Fens are peat-dominated wetlands that commonly rely on groundwater to supplement their water budget and deliver dissolved solutes that impart a distinct geochemistry, hence vegetation community. A numerical model was used to test the concept and guide selection of earth materials and system geometry. The goal was to maintain the placed peat in a sufficiently wet condition to support wetland plants and become a net carbon sink, in this sub-humid climate. The 32.1 ha Nikanotee Fen Watershed comprises a 7.7 ha upland, that was designed to recharge sufficient water, and deliver it to the 2.9 ha fen via groundwater flow. These features are surrounded by other reclaimed slopes designed to store water, rather than deliver it downslope. Four years of monitoring since construction show the fen maintains a high water table, and the peatland has become a strong carbon sink, even though the hydrological performance of construction materials varied substantially from what was anticipated (lower hydraulic conductivity). However, solutes associated with the tailings sand used in construction are moving towards the fen, and are expected to influence the future vegetation community and system biogeochemistry. One of the biggest uncertainties is the changing performance of soils and vegetation as they develop.

  8. Challenges in Modeling Disturbance Regimes and Their Impacts in Arctic and Boreal Ecosystems (Invited)

    Science.gov (United States)

    McGuire, A. D.; Rupp, T. S.; Kurz, W.

    2013-12-01

    lead to loss of forest cover through transitions of forested peatland plateaus to thermokarst lakes and to collapse scar fens and bogs. Major challenges to predicting thermokarst disturbance include (1) quantifying the area of land susceptible to thermokarst disturbance and quantifying how thermokarst is initiated and expands in response to a changing climate. Besides the challenges involved in modeling changes in different types of disturbance regimes, an important additional challenge is to understand interactions among changes in disturbance regimes, for example, the degree to which fire disturbance may be affected because of trees killed by insect outbreaks. Our comparison of what is known about the drivers and impacts of these disturbance regimes indicates that the accurate prediction of fire regimes in arctic and boreal regions is nearest a maturity stage for incorporation into Earth System Models. Rapid progress is needed in modeling changes in other disturbance types and their impacts to facilitate their incorporation into Earth System Models.

  9. Northern Peatland Shifts Under Changing Climate and Their Impact on Permafrost

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2018-04-01

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

  11. Peatland geoengineering: an alternative approach to terrestrial carbon sequestration.

    Science.gov (United States)

    Freeman, Christopher; Fenner, Nathalie; Shirsat, Anil H

    2012-09-13

    Terrestrial and oceanic ecosystems contribute almost equally to the sequestration of ca 50 per cent of anthropogenic CO(2) emissions, and already play a role in minimizing our impact on Earth's climate. On land, the majority of the sequestered carbon enters soil carbon stores. Almost one-third of that soil carbon can be found in peatlands, an area covering just 2-3% of the Earth's landmass. Peatlands are thus well established as powerful agents of carbon capture and storage; the preservation of archaeological artefacts, such as ancient bog bodies, further attest to their exceptional preservative properties. Peatlands have higher carbon storage densities per unit ecosystem area than either the oceans or dry terrestrial systems. However, despite attempts over a number of years at enhancing carbon capture in the oceans or in land-based afforestation schemes, no attempt has yet been made to optimize peatland carbon storage capacity or even to harness peatlands to store externally captured carbon. Recent studies suggest that peatland carbon sequestration is due to the inhibitory effects of phenolic compounds that create an 'enzymic latch' on decomposition. Here, we propose to harness that mechanism in a series of peatland geoengineering strategies whereby molecular, biogeochemical, agronomical and afforestation approaches increase carbon capture and long-term sequestration in peat-forming terrestrial ecosystems.

  12. Peatlands of the Peruvian Puna ecoregion: types, characteristics and disturbance

    Directory of Open Access Journals (Sweden)

    F. Salvador

    2014-05-01

    Full Text Available Peatlands represent one of the most important water resources in the Puna grassland ecoregion, but this fact is not yet widely recognised. Puna peatlands also provide key environmental services such as increasing the regional biodiversity of the Andean Altiplano plateau and contributing to the wellbeing of high-altitude human populations by providing grazing land and cooking fuel. We conducted a study in the Peruvian Puna ecoregion to describe the current condition of peatlands in terms of their vegetation, physical and chemical characteristics and disturbance status. Our results suggest that peat thickness, organic matter and degree of humification are good indicators for identifying peatlands in the Puna ecoregion. In general, the peatland sites that we sampled were dominated by mixtures of cushion and acaulescent rosette forming plants such as Distichia muscoides Nees & Meyen and Plantago tubulosa Decne. These Distichia and Plantago peatland sites were characterised by a mean surface water pH of 6.3, corrected electrical conductivity (K corr. in the range 300–1814 μS cm-1 and presented the following mean exchangeable cation values: Ca2+ 48 mg L-1, Mg2+ 9.6 mg L-1, Na+ 8.2 mg L-1 and K+ 2.1 mg L-1. The most common causes of disturbance we encountered were grazing, peat extraction and roads. Disturbance was most severe in mining sites, where peatlands are especially vulnerable because they are not under legal protection.

  13. Multi-method investigation of cushion peatlands (

    Science.gov (United States)

    Forbriger, M.; Schittek, K.; Höfle, B.; Siart, C.; Eitel, B.

    2012-04-01

    This study presents a multi-method and multi-proxy approach for palaeonvironmental investigations in the western andean cordillera of southern Peru (Lucanas province, 14° S) using cushion peatlands as terrestrial geoarchives. The region stretching between the Altiplano and the Peruvian desert in the lowland shares a long term settlement history, in which local cultures adapted to climate change in many different ways. Being one of the most outstanding human remains, the abri below Cerro Llamoca, 4.450 m a.s.l. in the uppermost ranges of the Llamoca peatland catchment area further reveals an occupation history of almost 10.000 years, as revealed by latest archaeological investigations. In remote and highly elevated regions such as the central Andes, cushion peatlands basically represent the only high resolution terrestrial archives suitable for geoarchaeological and palaeoenvironmental studies. Characterized by high accumulation rates, they ideally document environmental changes, particularly at small time intervals. Within the multidisciplinary project 'Andean Transect - Climate Sensitivity of pre-Columbian Man-Environment-Systems' several sediment cores with depths up to 11.5 m b.s. were recovered from the Llamoca peatland. Based on almost 100 AMS 14C-datings they provide a chronology of 8000 years and, thus, offer profound insights into climatic and environmental changes in the study area. While nearly homogeneous peat layers record stable environmental conditions, the heterogeneous granulometric composition of intercalated sediment layers documents several periods of intense geomorphodynamic activity. Due to high resolution geochemical analyses of peat layers (1 cm interval; humification degree, CNS measurements, XRF-scanning), the existence of slight and short-term trends of landscape development during these phases can be identified. Additional pollen, charred particles and plant macrofossil analyses confirm these findings and help reconstructing local

  14. Peatland Organic Matter Chemistry Trends Over a Global Latitudinal Gradient

    Science.gov (United States)

    Verbeke, B. A.; Hodgkins, S. B.; Carson, M. A.; Lamit, L. J.; Lilleskov, E.; Chanton, J.

    2017-12-01

    Peatlands contain a significant amount of the global soil carbon, and the climate feedback of carbon cycling within these peatland systems is still relatively unknown. Organic matter composition of peatlands plays a major role in determining carbon storage, and while high latitude peatlands seem to be the most sensitive to climate change, a global picture of peat organic matter chemistry is required to improve predictions and models of greenhouse gas emissions fueled by peatland decomposition. The objective of this research is to test the hypothesis that carbohydrate content of peatlands near the equator will be lower than high latitude peatlands, while aromatic content will be higher. As a part of the Global Peatland Microbiome Project (GPMP), around 2000 samples of peat from 10 to 70 cm across a latitudinal gradient of 79 N to 53 S were measured with Fourier transform infrared spectroscopy (FTIR) to examine the organic matter functional groups of peat. Carbohydrate and aromatic content, as determined by FTIR, are useful proxies of decomposition potential and recalcitrance, respectively. We found a highly significant relationship between carbohydrate and aromatic content, latitude, and depth. Carbohydrate content of high latitude sites were significantly greater than at sites near the equator, in contrast to aromatic content which showed the opposite trend. It is also clear that carbohydrate content decreases with depth while aromatic content increases with depth. Higher carbohydrate content at higher latitudes indicates a greater potential for lability and resultant mineralization to form the greenhouse gases, carbon dioxide and methane, whereas the composition of low latitude peatlands is consistent with their apparent stability. We speculate that the combination of low carbohydrates and high aromatics at warmer locations near the equator could foreshadow the organic matter composition of high latitude peat transitioning to a more recalcitrant form with a

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

    Science.gov (United States)

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

    2016-05-01

    Northern peatlands have accumulated one third of the Earth's soil carbon stock since the last Ice Age. Rapid warming across northern biomes threatens to accelerate rates of peatland ecosystem respiration. Despite compensatory increases in net primary production, greater ecosystem respiration could signal the release of ancient, century- to millennia-old carbon from the peatland organic matter stock. Warming has already been shown to promote ancient peatland carbon release, but, despite the key role of vegetation in carbon dynamics, little is known about how plants influence the source of peatland ecosystem respiration. Here, we address this issue using in situ (14)C measurements of ecosystem respiration on an established peatland warming and vegetation manipulation experiment. Results show that warming of approximately 1 °C promotes respiration of ancient peatland carbon (up to 2100 years old) when dwarf-shrubs or graminoids are present, an effect not observed when only bryophytes are present. We demonstrate that warming likely promotes ancient peatland carbon release via its control over organic inputs from vascular plants. Our findings suggest that dwarf-shrubs and graminoids prime microbial decomposition of previously 'locked-up' organic matter from potentially deep in the peat profile, facilitating liberation of ancient carbon as CO2. Furthermore, such plant-induced peat respiration could contribute up to 40% of ecosystem CO2 emissions. If consistent across other subarctic and arctic ecosystems, this represents a considerable fraction of ecosystem respiration that is currently not acknowledged by global carbon cycle models. Ultimately, greater contribution of ancient carbon to ecosystem respiration may signal the loss of a previously stable peatland carbon pool, creating potential feedbacks to future climate change. © 2016 John Wiley & Sons Ltd.

  16. Improved Hydrology over Peatlands in a Global Land Modeling System

    Science.gov (United States)

    Bechtold, M.; Delannoy, G.; Reichle, R.; Koster, R.; Mahanama, S.; Roose, Dirk

    2018-01-01

    Peatlands of the Northern Hemisphere represent an important carbon pool that mainly accumulated since the last ice age under permanently wet conditions in specific geological and climatic settings. The carbon balance of peatlands is closely coupled to water table dynamics. Consequently, the future carbon balance over peatlands is strongly dependent on how hydrology in peatlands will react to changing boundary conditions, e.g. due to climate change or regional water level drawdown of connected aquifers or streams. Global land surface modeling over organic-rich regions can provide valuable global-scale insights on where and how peatlands are in transition due to changing boundary conditions. However, the current global land surface models are not able to reproduce typical hydrological dynamics in peatlands well. We implemented specific structural and parametric changes to account for key hydrological characteristics of peatlands into NASA's GEOS-5 Catchment Land Surface Model (CLSM, Koster et al. 2000). The main modifications pertain to the modeling of partial inundation, and the definition of peatland-specific runoff and evapotranspiration schemes. We ran a set of simulations on a high performance cluster using different CLSM configurations and validated the results with a newly compiled global in-situ dataset of water table depths in peatlands. The results demonstrate that an update of soil hydraulic properties for peat soils alone does not improve the performance of CLSM over peatlands. However, structural model changes for peatlands are able to improve the skill metrics for water table depth. The validation results for the water table depth indicate a reduction of the bias from 2.5 to 0.2 m, and an improvement of the temporal correlation coefficient from 0.5 to 0.65, and from 0.4 to 0.55 for the anomalies. Our validation data set includes both bogs (rain-fed) and fens (ground and/or surface water influence) and reveals that the metrics improved less for fens. In

  17. Buffer design 2012

    International Nuclear Information System (INIS)

    Juvankoski, M.

    2013-08-01

    Posiva's spent nuclear fuel disposal is based on the KBS-3V concept and on the characteristics of the Olkiluoto site. In this concept single canisters containing spent nuclear fuel surrounded by a bentonite buffer are emplaced in individual vertical boreholes drilled in the floor of deposition tunnels in bedrock at about 420 m depth below ground level. Disk type bentonite blocks are installed at the bottom of the hole and on the top of the disposal canister. Ring type bentonite blocks surround the canisters. This report describes the detailed design of the buffer for a KBS-3V repository. The report presents the design basis, the reference design, and summarises the performance analyses carried out for the design. This report addresses aspects concerning the manufacture, quality control, mechanical strength, chemical resistance, thermal dimensioning, handling of buffer components and material ageing phenomena including the effect of radiation. Interaction of buffer and other engineered barriers are included in the study. The long-term evolution of the repository and its effective drivers are considered if they have an impact on the buffer performance but operational safety aspects are also included because they may affect long-term safety. (orig.)

  18. Insect biodiversity of boreal peat bogs

    Czech Academy of Sciences Publication Activity Database

    Spitzer, Karel; Danks, H. V.

    2006-01-01

    Roč. 51, - (2006), s. 137-161 ISSN 0066-4170 R&D Projects: GA ČR(CZ) GA206/97/0077; GA AV ČR(CZ) IBS5007015 Institutional research plan: CEZ:AV0Z50070508 Keywords : peatlands * tyrphobiontic insects * conservation Subject RIV: EH - Ecology, Behaviour Impact factor: 8.714, year: 2006

  19. The SVT Hit Buffer

    International Nuclear Information System (INIS)

    Belforte, S.; Dell'Orso, M.; Donati, S.

    1996-01-01

    The Hit Buffer is part of the Silicon Vertex Tracker, a trigger processor dedicated to the reconstruction of particle trajectories in the Silicon Vertex Detector and the Central Tracking Chamber of the Collider Detector at Fermilab. The Hit Buffer is a high speed data-traffic node, where thousands of words are received in arbitrary order and simultaneously organized in an internal structured data base, to be later promptly retrieved and delivered in response to specific requests. The Hit Buffer is capable of processing data at a rate of 25 MHz, thanks to the use of special fast devices like Cache-Tag RAMs and high performance Erasable Programmable Logic Devices from the XILINX XC7300 family

  20. A parallel buffer tree

    DEFF Research Database (Denmark)

    Sitchinava, Nodar; Zeh, Norbert

    2012-01-01

    We present the parallel buffer tree, a parallel external memory (PEM) data structure for batched search problems. This data structure is a non-trivial extension of Arge's sequential buffer tree to a private-cache multiprocessor environment and reduces the number of I/O operations by the number of...... in the optimal OhOf(psortN + K/PB) parallel I/O complexity, where K is the size of the output reported in the process and psortN is the parallel I/O complexity of sorting N elements using P processors....

  1. Spontaneous revegetation of mined peatlands in eastern Canada

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, M.; Rochefort, L.; Quinty, F.; Lavoie, C [Laval University, Quebec, QC (Canada)

    2005-05-15

    Revegetation patterns of sphagnum recolonization at abandoned mined peatlands are assessed, based on a survey of 26 abandoned harvested peatlands, in the provinces of Quebec and New Brunswick. The impact of local and regional variables and the length of time since abandonment are examined. The vegetation structure of all 2571 trenches and 2595 blocks of abandoned block-cut areas and in all 395 vacuum fields of the mechanically mined areas was recorded. The species at 243 recolonized peat fields (selected by random sampling) were analyzed. The abandoned surfaces were found to be distinctly different depending on whether peat extraction was by hand block-cutting or vacuum mining methods. Block-cut peatlands recovered well; herb cover was similar to that in natural peatlands. Practically no sphagnum species recolonized the vacuum- mined peat fields. The species diversity in abandoned mined peat fields was observed to be high. 72 refs., 3 figs., 5 tabs., 1 app.

  2. Buffer Zone Sign Template

    Science.gov (United States)

    The certified pesticide applicator is required to post a comparable sign, designating a buffer zone around the soil fumigant application block in order to control exposure risk. It must include the don't walk symbol, product name, and applicator contact.

  3. Buffer Zone, Nicosia

    OpenAIRE

    Sorensen, Marie Louise

    2010-01-01

    Images of the United Nations Buffer Zone or Green Line which has partitioned Cyprus since 1974 The research leading to these results has received funding from the European Community's Seventh Framework Programme [FP7/2007-2013] under grant agreement n° 217411.

  4. Status of peatland degradation and development in Sumatra and Kalimantan.

    Science.gov (United States)

    Miettinen, Jukka; Liew, Soo Chin

    2010-01-01

    Peatlands cover around 13 Mha in Sumatra and Kalimantan, Indonesia. Human activities have rapidly increased in the peatland ecosystems during the last two decades, invariably degrading them and making them vulnerable to fires. This causes high carbon emissions that contribute to global climate change. For this article, we used 94 high resolution (10-20 m) satellite images to map the status of peatland degradation and development in Sumatra and Kalimantan using visual image interpretation. The results reveal that less than 4% of the peatland areas remain covered by pristine peatswamp forests (PSFs), while 37% are covered by PSFs with varying degree of degradation. Furthermore, over 20% is considered to be unmanaged degraded landscape, occupied by ferns, shrubs and secondary growth. This alarming extent of degradation makes peatlands vulnerable to accelerated peat decomposition and catastrophic fire episodes that will have global consequences. With on-going degradation and development the existence of the entire tropical peatland ecosystem in this region is in great danger.

  5. Fire Behavior in Pelalawan Peatland, Riau Province

    Directory of Open Access Journals (Sweden)

    BAMBANG HERO SAHARJO

    2006-01-01

    Full Text Available During dry season it is easily recognized that smoke will emerge at certain place both in Sumatra and Kalimantan that is in peatland. The worst situation occurred when fire burnt buried log in the logged over area where the fire fighter did not have any experience and knowledge on how to work with fire in peatland. Finally it had been found that one of the reasons why firefighter failed to fight fire in peatland is because they do not have any knowledge and experience on it. In order to know the fire behavior characteristics in different level of peat decomposition for fire management and sustainable management of the land for the community, research done in Pelalawan area, Riau Province, Indonesia, during dry season 2001. Three level of peat decomposition named Sapric, Hemic, and Fibric used. To conduct the research, two 400 m2 of plot each was established in every level of the peat decomposition. Burning done three weeks following slashing, cutting and drying at different time using circle method. During burning, flame length, rate of the spread of fire, flame temperature and following burning fuel left and the depth of peat destruction were measured. Results of research shown that in sapric site where sapric 2 has fuel load 9 ton ha-1 less than sapric 1, fire behavior was significantly different while peat destructed was deepest in sapric 2 with 31.87 cm. In hemic site where hemic 2 has fuel load 12.3 ton ha-1 more than hemic 1, fire behavior was significantly different and peat destructed deeper than hemic 1 that was 12.6 cm. In fibric site where fibric 1 has fuel load 3.5 ton ha-1 more than fibric 1, fire behavior was significantly different that has no burnt peat found. This results found that the different fuel characteristics (potency, moisture, bed depth, and type at the same level of peat decomposition will have significantly different fire behavior as it happened also on the depth of peat destruction except fibric. The same condition

  6. Nutrients and Hydrology Indicate the Driving Mechanisms of Peatland Surface Patterning

    NARCIS (Netherlands)

    Eppinga, M.B.; Ruiter, de P.C.; Wassen, M.J.; Rietkerk, M.

    2009-01-01

    Peatland surface patterning motivates studies that identify underlying structuring mechanisms. Theoretical studies so far suggest that different mechanisms may drive similar types of patterning. The long time span associated with peatland surface pattern formation, however, limits possibilities for

  7. Peatland Carbon Dynamics in Alaska During Past Warm Climates

    Science.gov (United States)

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

    2013-12-01

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

  8. Nitrogen removal in Northern peatlands treating mine wastewaters

    Science.gov (United States)

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

    2015-04-01

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

  9. Nitrogen alters carbon dynamics during early succession in boreal forest

    Science.gov (United States)

    Steven D. Allison; Tracy B. Gartner; Michelle C. Mack; Krista McGuire; Kathleen. Treseder

    2010-01-01

    Boreal forests are an important source of wood products, and fertilizers could be used to improve forest yields, especially in nutrient poor regions of the boreal zone. With climate change, fire frequencies may increase, resulting in a larger fraction of the boreal landscape present in early successional stages. Since most fertilization studies have focused on mature...

  10. Boreal mire carbon exchange: sensitivity to climate change and anthropogenic nitrogen and sulfur deposition

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, Tobias

    2010-07-01

    Boreal peatlands are important long-term sinks of atmospheric carbon and in the same time the largest natural source of methane to the atmosphere. A changing climate as well as deposition of anthropogenically derived pollutants, such as nitrogen and sulfur, has the potential to affect the processes that control the carbon exchange in peatlands. Many of the biogeochemical responses to changed environmental conditions, such as changed plant community composition, are slow and therefore long-term studies are required. In this thesis I have investigated the long-term effects of nitrogen addition, sulfur addition and greenhouse enclosures on carbon exchange by using a field manipulation experiment in a boreal minerogenic, oligotrophic mire after 10-12 years of treatment. Treatment effects on CH{sub 4} emissions, gross primary production (GPP), ecosystem respiration (Reco) and net ecosystem exchange (NEE) were estimated from 1-2 seasons of chamber flux measurements. Treatment effects on potential CH{sub 4} production and oxidation were estimated in incubations of peat from different depth intervals. The effect of nitrogen deposition on carbon accumulation was evaluated in peat cores at different depth intervals. The long-term nitrogen additions have: shifted plant community composition from being dominated by Sphagnum to being dominated by sedges and dwarf shrubs; changed mire surface microtopography so that mean water table is closer to the surface in plots with high nitrogen; increased CH{sub 4} production and emission; increased Reco slightly but have not affected GPP or NEE; reduced the peat height increment, but increased both peat bulk density and carbon content, leading to an unchanged carbon accumulation. The long-term sulfur additions have not reduced CH{sub 4} emissions, only slightly reduced CH{sub 4} production and did not have any effect on the CO{sub 2} carbon exchange. The greenhouse treatment, manifested in increased air and soil temperatures, reduced

  11. Creep in buffer clay

    International Nuclear Information System (INIS)

    Pusch, R.; Adey, R.

    1999-12-01

    The study involved characterization of the microstructural arrangement and molecular forcefields in the buffer clay for getting a basis for selecting suitable creep models. It is concluded that the number of particles and wide range of the particle bond spectrum require that stochastical mechanics and thermodynamics will be considered and they are basic to the creep model proposed for predicting creep settlement of the canisters. The influence of the stress level on creep strain of MX-80 clay is not well known but for the buffer creep is approximately proportional to stress. Theoretical considerations suggest a moderate impact for temperatures up to 90 deg C and this is supported by model experiments. It is believed that the assumption of strain being proportional to temperature is conservative. The general performance of the stochastic model can be illustrated in principle by use of visco-elastic rheological models implying a time-related increase in viscosity. The shear-induced creep settlement under constant volume conditions calculated by using the proposed creep model is on the order of 1 mm in ten thousand years and up to a couple of millimeters in one million years. It is much smaller than the consolidation settlement, which is believed to be on the order of 10 mm. The general conclusion is that creep settlement of the canisters is very small and of no significance to the integrity of the buffer itself or of the canisters

  12. Boreal Forest Fire Cools Climate

    Science.gov (United States)

    Randerson, J. T.; Liu, H.; Flanner, M.; Chambers, S. D.; Harden, J. W.; Hess, P. G.; Jin, Y.; Mack, M. C.; Pfister, G.; Schuur, E. A.; Treseder, K. K.; Welp, L. R.; Zender, C. S.

    2005-12-01

    We report measurements, modeling, and analysis of carbon and energy fluxes from a boreal forest fire that occurred in interior Alaska during 1999. In the first year after the fire, ozone production, atmospheric aerosol loading, greenhouse gas emissions, soot deposition, and decreases in summer albedo contributed to a positive annual radiative forcing (RF). These effects were partly offset by an increase in fall, winter, and spring albedo from reduced canopy cover and increased exposure of snow-covered surfaces. The atmospheric lifetime of aerosols and ozone and are relatively short (days to months). The radiative effects of soot on snow are also attenuated rapidly from the deposition of fresh snow. As a result, a year after the fire, only two classes of RF mechanisms remained: greenhouse gas emissions and post-fire changes in surface albedo. Summer albedo increased rapidly in subsequent years and was substantially higher than unburned control areas (by more than 0.03) after 4 years as a result of grass and shrub establishment. Satellite measurements from MODIS of other interior Alaska burn scars provided evidence that elevated levels of spring and summer albedo (relative to unburned control areas) persisted for at least 4 decades after fire. In parallel, our chamber, eddy covariance, and biomass measurements indicated that the post-fire ecosystems switch from a source to a sink within the first decade. Taken together, the extended period of increased spring and summer albedo and carbon uptake of intermediate-aged stands appears to more than offset the initial warming pulse caused by fire emissions, when compared using the RF concept. This result suggests that management of forests in northern countries to suppress fire and preserve carbon sinks may have the opposite effect on climate as that intended.

  13. Restoration Ecology of Lowland tropical Peatlands in Southeast Asia: Current Knowledge and Future Research Directions

    NARCIS (Netherlands)

    Page, S.; Hoscilo, A.; Wösten, J.H.M.; Jauhiainen, J.; Silvius, M.J.; Rieley, J.; Ritzema, H.P.; Tansey, K.; Graham, L.; Vasander, H.; Limin, S.

    2009-01-01

    Studies of restoration ecology are well established for northern peatlands, but at an early stage for tropical peatlands. Extensive peatland areas in Southeast Asia have been degraded through deforestation, drainage and fire, leading to on- and off-site environmental and socio-economic impacts of

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

    Science.gov (United States)

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

    2015-01-01

    Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth...

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

    Science.gov (United States)

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

    2015-09-15

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

  16. Microform-related community patterns of methane-cycling microbes in boreal Sphagnum bogs are site specific.

    Science.gov (United States)

    Juottonen, Heli; Kotiaho, Mirkka; Robinson, Devin; Merilä, Päivi; Fritze, Hannu; Tuittila, Eeva-Stiina

    2015-09-01

    Vegetation and water table are important regulators of methane emission in peatlands. Microform variation encompasses these factors in small-scale topographic gradients of dry hummocks, intermediate lawns and wet hollows. We examined methane production and oxidization among microforms in four boreal bogs that showed more variation of vegetation within a bog with microform than between the bogs. Potential methane production was low and differed among bogs but not consistently with microform. Methane oxidation followed water table position with microform, showing higher rates closer to surface in lawns and hollows than in hummocks. Methanogen community, analysed by mcrA terminal restriction fragment length polymorphism and dominated by Methanoregulaceae or 'Methanoflorentaceae', varied strongly with bog. The extent of microform-related variation of methanogens depended on the bog. Methanotrophs identified as Methylocystis spp. in pmoA denaturing gradient gel electrophoresis similarly showed effect of bog, and microform patterns were stronger within individual bogs. Our results suggest that methane-cycling microbes in boreal Sphagnum bogs with seemingly uniform environmental conditions may show strong site-dependent variation. The bog-intrinsic factor may be related to carbon availability but contrary to expectations appears to be unrelated to current surface vegetation, calling attention to the origin of carbon substrates for microbes in bogs. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Preferences of Local People for the Use of Peatlands: the Case of the Richest Peatland Region in Finland

    Directory of Open Access Journals (Sweden)

    Anne Tolvanen

    2013-06-01

    Full Text Available We analyze the potential for socioeconomically sustainable peatland use by investigating conflicting interests, revealing trade-offs that people are willing to accept, and studying whether opinions are dependent on socioeconomic and demographic factors. Opinions toward five forms of peatland use and seven peatland ecosystem services were surveyed in Northern Ostrobothnia in northern Finland in 2011. Choice experiment (CE was used to reveal trade-offs in land use preferences, and groups of respondents were identified using the latent class model (LCM. We identified three classes of respondents in which environmentalists showed a high preference toward the cessation of peat production and increase of peatland restoration, the production-oriented class preferred an increase in timber and peat production areas, and the current use supporters agreed on the present land use policy. However, all respondent classes agreed on the increase of nature protection and the present level of timber production and disagreed on the cessation of restoration. The CE revealed that environmentally minded people who are likely to consider the indirect use values and existence values important are less willing to make trade-offs between ecosystem services than those who emphasize direct use values. Because peatland restoration occurs in commercially unproductive peatlands, it improves both the direct use and existence values without reducing provisioning services of peatlands. Therefore, restoration is commonly accepted by the public, in contrast to management options that involve clear trade-offs between ecosystem services. We conclude that the understanding of preferences and trade-offs can enhance sustainable land use planning. It may be unrealistic, however, to expect a solution that all interest groups would completely accept.

  18. Towards a Global High Resolution Peatland Map in 2020

    Science.gov (United States)

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

    2015-04-01

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

  19. Airborne Electromagnetic Mapping of Peatlands: a Case Study in Norway.

    Science.gov (United States)

    Silvestri, S.; Viezzoli, A.; Pfaffhuber, A. A.; Vettore, A.

    2017-12-01

    Peatlands are extraordinary reservoirs of organic carbon that can be found over a wide range of latitudes, in tropical, to temperate, to (sub)polar climates. According to some estimates, the carbon stored in peatlands almost match the atmospheric carbon pool. Peatlands degradation due to natural and anthropogenic factors releases every year large amount of CO2 and other green house gasses into the atmosphere. The conservation of peatlands is therefore a key measure to reduce emissions and to mitigate climate change. An effective plan to prevent peatlands degradation must move from a precise estimate of the volume of peat stored across vast territories around the world. One example are the several bogs that characterize large surfaces in Norway. Our research combines the use of high spatial resolution satellite optical data with Airborne Electromagnetic (AEM) and field measurements in order to map the extension and thickness of peat in Brøttum, Ringsaker province, Norway. The methodology allows us to quantify the volume of peat as well as the organic carbon stock. The variable thickness typical of Norwegian bogs allows us to test the limits of the AEM methodology in resolving near surface peat layers. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 747809. Start date: 1 June 2017. Duration: 24 months

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

    Science.gov (United States)

    Page, S E; Hooijer, A

    2016-06-05

    Peatlands are a significant component of the global carbon (C) cycle, yet despite their role as a long-term C sink throughout the Holocene, they are increasingly vulnerable to destabilization. Nowhere is this shift from sink to source happening more rapidly than in Southeast Asia, and nowhere else are the combined pressures of land-use change and fire on peatland ecosystem C dynamics more evident nor the consequences more apparent. This review focuses on the peatlands of this region, tracing the link between deforestation and drainage and accelerating C emissions arising from peat mineralization and fire. It focuses on the implications of the recent increase in fire occurrence for air quality, human health, ecosystem resilience and the global C cycle. The scale and controls on peat-driven C emissions are addressed, noting that although fires cause large, temporary peaks in C flux to the atmosphere, year-round emissions from peat mineralization are of a similar magnitude. The review concludes by advocating land management options to reduce future fire risk as part of wider peatland management strategies, while also proposing that this region's peat fire dynamic could become increasingly relevant to northern peatlands in a warming world.This article is part of the themed issue 'The interaction of fire and mankind'. © 2016 The Author(s).

  1. Buffered or under Scrutiny?

    DEFF Research Database (Denmark)

    Klopf, Patricia; Nell, Phillip C.; Puck, Jonas

    – they are to a stronger extent buffered from the external environment than small firms. Thus, this paper adds to previous research by disentangling the complex effects of size on the use of political strategies – a strand of literature which has been characterized by inconsistent findings in the past.......This paper investigates political strategies of MNE subsidiaries operating in emerging markets. Our findings support previous findings of more intense political strategies in the presence of stronger institutional pressures from public and private stakeholders. Furthermore, we hypothesize...

  2. Environmental and biogeochemical controls on N2 fixation in ombrotrophic peatlands

    Science.gov (United States)

    Zivkovic, T.; Moore, T. R.

    2017-12-01

    Northern peatlands have low atmospheric nitrogen (N) inputs and acquire N mostly via biological, microbially-driven N2-fixation. Little is known about rates and controls on N2-fixation in ombrotrophic bogs. We conducted two studies to test environmental and biogeochemical controls on N2-fixation. First, we used acetylene reduction assay (ARA) calibrated with 15N2 tracer to measure N2-fixation rates in three species of Sphagnum mosses along a hydrological gradient (beaver pond, hollow and hummock in bog margin and in bog) at Mer Bleue bog from June-October 2013 and May - November 2014. We tested the following controls: moisture availability, temperature, and PAR. The largest ARA rates throughout both seasons occurred in the pond in floating Sphagnum cuspidatum mats (50.3 ± 12.9 μmol m-2 d-1 Mean ± SE), which were up to 2.5 times larger than the rates found in the driest hummock site. There was a significant seasonal peak in both years in July and early August that coincided with the peak of the air temperature. In fact, 45% of the variance of N2 fixation rates over the two field seasons was explained by rain events, water table fluctuations and the surface peat temperature (multiple regression analysis, n = 539). Our results highlight the potential impact of climate change, namely negative effects due to potential droughts and positive effect of warming, on N2 fixation patterns in ombrotrophic peatlands. Secondly, we tested stoichiometric controls (Sphagnum tissue N and phosphorous (P) ratio) of N2-fixation. In a controlled environment, we selected eight study sites along a latitudinal gradient from temperate, boreal to subarctic zone in eastern Canada. We found that decreasing N:P ratio corresponded to increasing N2-fixation. N:P explained 65% of the variance in N2-fixation in hollows but only 20% in hummocks. Changes in neither N or P concentration alone explained the increase in N2-fixation better than N:P ratio. We interpret that the difference between

  3. Chapter 8. Current management situation: Boreal owls

    Science.gov (United States)

    Jon Verner

    1994-01-01

    The range of boreal owls (Aegolius funereus) in the United States includes Alaska, the mountains of the western United States, and the northern tier states from the Atlantic to Pacific (see Chapter 9). Based on the species' documented distribution (see National Geographic Society 1987, Hayward et al. 1987, Johnsgard 1988, and others) the owl may...

  4. Natural glyphosate tolerance in sweetvetch Hedysarum boreale

    Science.gov (United States)

    Sweetvetch (Hedysarum boreale Nutt.) a legume native to the western USA and Canada, is purported to have tolerance to glyphosate {N-(phosphonomethyl) glycine} herbide. Eight rates of glyphosate were tested for their effect on biomass yield (BMY) and survival of seedlings and mature plants. Treatme...

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

    Science.gov (United States)

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

    2016-01-01

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

  6. The short-term effects of management changes on watertable position and nutrients in shallow groundwater in a harvested peatland forest.

    Science.gov (United States)

    Finnegan, J; Regan, J T; Fenton, O; Lanigan, G J; Brennan, R B; Healy, M G

    2014-09-01

    Management changes such as drainage, fertilisation, afforestation and harvesting (clearfelling) of forested peatlands influence watertable (WT) position and groundwater concentrations of nutrients. This study investigated the impact of clearfelling of a peatland forest on WT and nutrient concentrations. Three areas were examined: (1) a regenerated riparian peatland buffer (RB) clearfelled four years prior to the present study (2) a recently clearfelled coniferous forest (CF) and (3) a standing, mature coniferous forest (SF), on which no harvesting took place. The WT remained consistently below 0.3 m during the pre-clearfelling period. Results showed there was an almost immediate rise in the WT after clearfelling and a rise to 0.15 m below ground level (bgl) within 10 months of clearfelling. Clearfelling of the forest increased dissolved reactive phosphorus concentrations (from an average of 28-230 μg L(-1)) in the shallow groundwater, likely caused by leaching from degrading brash mats. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Investigating the episodic buffer

    Directory of Open Access Journals (Sweden)

    Alan Baddeley

    2010-10-01

    Full Text Available A brief account is presented of the three-component working memory model proposed by Baddeley and Hitch. This is followed by an account of some of the problems it encountered in explaining how information from different subsystems with different codes could be combined, and how it was capable of communicating with long-term memory. In order to account for these, a fourth component was proposed, the episodic buffer. This was assumed to be a multidimensional store of limited capacity that can be accessed through conscious awareness. In an attempt to test and develop the concept, a series of experiments have explored the role of working memory in the binding of visual features into objects and verbal sequences into remembered sentences. The experiments use a dual task paradigm to investigate the role of the various subcomponents of working memory in binding. In contrast to our initial assumption, the episodic buffer appears to be a passive store, capable of storing bound features and making them available to conscious awareness, but not itself responsible for the process of binding.

  8. Browning boreal forests of western North America

    Science.gov (United States)

    Verbyla, David

    2011-12-01

    The GIMMS NDVI dataset has been widely used to document a 'browning trend' in North American boreal forests (Goetz et al 2005, Bunn et al 2007, Beck and Goetz 2011). However, there has been speculation (Alcaraz-Segura et al 2010) that this trend may be an artifact due to processing algorithms rather than an actual decline in vegetation activity. This conclusion was based primarily on the fact that GIMMS NDVI did not capture NDVI recovery within most burned areas in boreal Canada, while another dataset consistently showed post-fire increasing NDVI. I believe that the results of Alcaraz-Segura et al (2010) were due simply to different pixel sizes of the two datasets (64 km2 versus 1 km2 pixels). Similar results have been obtained from tundra areas greening in Alaska, with the results simply due to these pixel size differences (Stow et al 2007). Furthermore, recent studies have documented boreal browning trends based on NDVI from other sensors. Beck and Goetz (2011) have shown the boreal browning trend derived from a different sensor (MODIS) to be very similar to the boreal browning trend derived from the GIMMS NDVI dataset for the circumpolar boreal region. Parent and Verbyla (2010) found similar declining NDVI patterns based on NDVI from Landsat sensors and GIMMS NDVI in boreal Alaska. Zhang et al (2008) found a similar 'browning trend' in boreal North America based on a production efficiency model using an integrated AVHRR and MODIS dataset. The declining NDVI trend in areas of boreal North America is consistent with tree-ring studies (D'Arrigo et al 2004, McGuire et al 2010, Beck et al 2011). The decline in tree growth may be due to temperature-induced drought stress (Barber et al 2000) caused by higher evaporative demands in a warming climate (Lloyd and Fastie 2002). In a circumpolar boreal study, Lloyd and Bunn (2007) found that a negative relationship between temperature and tree-ring growth occurred more frequently in warmer parts of species' ranges

  9. Delineation of peatland lagg boundaries from airborne LiDAR

    Science.gov (United States)

    Langlois, Melanie N.; Richardson, Murray C.; Price, Jonathan S.

    2017-09-01

    In Canada, peatlands are the most common type of wetland, but boundary delineation in peatland complexes has received little attention in the scientific literature. Typically, peatland boundaries are mapped as crisp, absolute features, and the transitional lagg zone—the ecotone found between a raised bog and the surrounding mineral land—is often overlooked. In this study, we aim (1) to advance existing approaches for detecting and locating laggs and lagg boundaries using airborne LiDAR surveys and (2) to describe the spatial distribution of laggs around raised bog peatlands. Two contrasting spatial analytical approaches for lagg detection were tested using five LiDAR-derived topographic and vegetation indices: topography, vegetation height, topographic wetness index, the standard deviation of the vegetation's height (as a proxy for the complexity of the vegetation's structure), and local indices of elevation variance. Using a dissimilarity approach (edge-detection, split-moving window analysis), no one variable accurately depicted both the lagg-mineral land and bog-lagg boundaries. Some indicators were better at predicting the bog-lagg boundary (i.e., vegetation height) and others at finding the lagg-mineral land boundary (i.e., topography). Dissimilarity analysis reinforces the usefulness of derived variables (e.g., wetness indices) in locating laggs, especially for those with weak topographic and vegetation gradients. When the lagg was confined between the bog and the adjacent upland, it took a linear form, parallel to the peatland's edge and was easier to predict. When the adjacent mineral land was flat or sloping away from the peatland, the lagg was discontinuous and intermittent and more difficult to predict.

  10. Soil Carbon Chemistry and Greenhouse Gas Production in Global Peatlands

    Science.gov (United States)

    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.

  11. Peatland Acidobacteria with a dissimilatory sulfur metabolism.

    Science.gov (United States)

    Hausmann, Bela; Pelikan, Claus; Herbold, Craig W; Köstlbacher, Stephan; Albertsen, Mads; Eichorst, Stephanie A; Glavina Del Rio, Tijana; Huemer, Martin; Nielsen, Per H; Rattei, Thomas; Stingl, Ulrich; Tringe, Susannah G; Trojan, Daniela; Wentrup, Cecilia; Woebken, Dagmar; Pester, Michael; Loy, Alexander

    2018-02-23

    Sulfur-cycling microorganisms impact organic matter decomposition in wetlands and consequently greenhouse gas emissions from these globally relevant environments. However, their identities and physiological properties are largely unknown. By applying a functional metagenomics approach to an acidic peatland, we recovered draft genomes of seven novel Acidobacteria species with the potential for dissimilatory sulfite (dsrAB, dsrC, dsrD, dsrN, dsrT, dsrMKJOP) or sulfate respiration (sat, aprBA, qmoABC plus dsr genes). Surprisingly, the genomes also encoded DsrL, which so far was only found in sulfur-oxidizing microorganisms. Metatranscriptome analysis demonstrated expression of acidobacterial sulfur-metabolism genes in native peat soil and their upregulation in diverse anoxic microcosms. This indicated an active sulfate respiration pathway, which, however, might also operate in reverse for dissimilatory sulfur oxidation or disproportionation as proposed for the sulfur-oxidizing Desulfurivibrio alkaliphilus. Acidobacteria that only harbored genes for sulfite reduction additionally encoded enzymes that liberate sulfite from organosulfonates, which suggested organic sulfur compounds as complementary energy sources. Further metabolic potentials included polysaccharide hydrolysis and sugar utilization, aerobic respiration, several fermentative capabilities, and hydrogen oxidation. Our findings extend both, the known physiological and genetic properties of Acidobacteria and the known taxonomic diversity of microorganisms with a DsrAB-based sulfur metabolism, and highlight new fundamental niches for facultative anaerobic Acidobacteria in wetlands based on exploitation of inorganic and organic sulfur molecules for energy conservation.

  12. Northern peatland carbon stocks and dynamics: a review

    Directory of Open Access Journals (Sweden)

    Z. C. Yu

    2012-10-01

    Full Text Available Peatlands contain a large belowground carbon (C stock in the biosphere, and their dynamics have important implications for the global carbon cycle. However, there are still large uncertainties in C stock estimates and poor understanding of C dynamics across timescales. Here I review different approaches and associated uncertainties of C stock estimates in the literature, and on the basis of the literature review my best estimate of C stocks and uncertainty is 500 ± 100 (approximate range gigatons of C (Gt C in northern peatlands. The greatest source of uncertainty for all the approaches is the lack or insufficient representation of data, including depth, bulk density and carbon accumulation data, especially from the world's large peatlands. Several ways to improve estimates of peat carbon stocks are also discussed in this paper, including the estimates of C stocks by regions and further utilizations of widely available basal peat ages.

    Changes in peatland carbon stocks over time, estimated using Sphagnum (peat moss spore data and down-core peat accumulation records, show different patterns during the Holocene, and I argue that spore-based approach underestimates the abundance of peatlands in their early histories. Considering long-term peat decomposition using peat accumulation data allows estimates of net carbon sequestration rates by peatlands, or net (ecosystem carbon balance (NECB, which indicates more than half of peat carbon (> 270 Gt C was sequestrated before 7000 yr ago during the Holocene. Contemporary carbon flux studies at 5 peatland sites show much larger NECB during the last decade (32 ± 7.8 (S.E. g C m−2 yr–1 than during the last 7000 yr (∼ 11 g C m−2 yr–1, as modeled from peat records across northern peatlands. This discrepancy highlights the urgent need for carbon accumulation data and process understanding, especially at decadal and centennial timescales

  13. The Methane to Carbon Dioxide Ratio Produced during Peatland Decomposition and a Simple Approach for Distinguishing This Ratio

    Science.gov (United States)

    Chanton, J.; Hodgkins, S. B.; Cooper, W. T.; Glaser, P. H.; Corbett, J. E.; Crill, P. M.; Saleska, S. R.; Rich, V. I.; Holmes, B.; Hines, M. E.; Tfaily, M.; Kostka, J. E.

    2014-12-01

    Peatland organic matter is cellulose-like with an oxidation state of approximately zero. When this material decomposes by fermentation, stoichiometry dictates that CH4 and CO2 should be produced in a ratio approaching one. While this is generally the case in temperate zones, this production ratio is often departed from in boreal peatlands, where the ratio of belowground CH4/CO2 production varies between 0.1 and 1, indicating CO2 production by a mechanism in addition to fermentation. The in situ CO2/CH4 production ratio may be ascertained by analysis of the 13C isotopic composition of these products, because CO2 production unaccompanied by methane production produces CO2 with an isotopic composition similar to the parent organic matter while methanogenesis produces 13C depleted methane and 13C enriched CO2. The 13C enrichment in the subsurface CO2 pool is directly related to the amount of if formed from methane production and the isotopic composition of the methane itself. Excess CO2 production is associated with more acidic conditions, Sphagnum vegetation, high and low latitudes, methane production dominated by hydrogenotrophic methane production, 13C depleted methane, and generally, more nutrient depleted conditions. Three theories have been offered to explain these observations— 1) inhibition of acetate utilization, acetate build-up and diffusion to the surface and eventual aerobic oxidation, 2) the use of humic acids as electron acceptors, and the 3) utilization of organic oxygen to produce CO2. In support of #3, we find that 13C-NMR, Fourier transform infrared (FT IR) spectroscopy, and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) clearly show the evolution of polysaccharides and cellulose towards more decomposed humified alkyl compounds stripped of organic oxygen utilized to form CO2. Such decomposition results in more negative carbon oxidation states varying from -1 to -2. Coincident with this reduction in oxidation state, is the

  14. Annual and monthly range fidelity of female boreal woodland caribou in respons to petroleum development

    Directory of Open Access Journals (Sweden)

    Boyan V. Tracz

    2010-03-01

    Full Text Available Petroleum-sector development in northern Alberta, Canada has been implicated as one factor influencing the decline of boreal woodland caribou (Rangifer tarandus caribou. Previous research showed that caribou are farther from petroleum-sector disturbances within their home range than expected. As petroleum development increases, the distance caribou can selectively place themselves relative to industrial disturbance must decrease, because distances between disturbances decrease. Conceptually, the number of local disturbances becomes so large that caribou either abandon their local avoidance behaviour or leave their traditional home range. We evaluated whether an intense petroleum- development event in northern Alberta was sufficient to result in home range abandonment by female woodland caribou. Using well locations as an index of petroleum development, we found that caribou studied from 1992 to 2000 did not change their annual or monthly range fidelity as a function of development intensity. Caribou remained in peatland complexes containing a large number of petroleum-sector disturbances rather than move to new areas, presumably because the risks of dispersing across upland habitat to reach other suitable habitat are high. Such range fidelity may have fitness consequences for woodland caribou if they suffer greater predation in areas where petroleum development is occurring.

  15. Biomass production efficiency controlled by management in temperate and boreal ecosystems

    Science.gov (United States)

    Campioli, M.; Vicca, S.; Luyssaert, S.; Bilcke, J.; Ceschia, E.; Chapin, F. S., III; Ciais, P.; Fernández-Martínez, M.; Malhi, Y.; Obersteiner, M.; Olefeldt, D.; Papale, D.; Piao, S. L.; Peñuelas, J.; Sullivan, P. F.; Wang, X.; Zenone, T.; Janssens, I. A.

    2015-11-01

    Plants acquire carbon through photosynthesis to sustain biomass production, autotrophic respiration and production of non-structural compounds for multiple purposes. The fraction of photosynthetic production used for biomass production, the biomass production efficiency, is a key determinant of the conversion of solar energy to biomass. In forest ecosystems, biomass production efficiency was suggested to be related to site fertility. Here we present a database of biomass production efficiency from 131 sites compiled from individual studies using harvest, biometric, eddy covariance, or process-based model estimates of production. The database is global, but dominated by data from Europe and North America. We show that instead of site fertility, ecosystem management is the key factor that controls biomass production efficiency in terrestrial ecosystems. In addition, in natural forests, grasslands, tundra, boreal peatlands and marshes, biomass production efficiency is independent of vegetation, environmental and climatic drivers. This similarity of biomass production efficiency across natural ecosystem types suggests that the ratio of biomass production to gross primary productivity is constant across natural ecosystems. We suggest that plant adaptation results in similar growth efficiency in high- and low-fertility natural systems, but that nutrient influxes under managed conditions favour a shift to carbon investment from the belowground flux of non-structural compounds to aboveground biomass.

  16. Buffer moisture protection system

    International Nuclear Information System (INIS)

    Ritola, J.; Peura, J.

    2013-11-01

    With the present knowledge, bentonite blocks have to be protected from the air relative humidity and from any moisture leakages in the environment that might cause swelling of the bentonite blocks during the 'open' installation phase before backfilling. The purpose of this work was to design the structural reference solution both for the bottom of the deposition hole and for the buffer moisture protection and dewatering system with their integrated equipment needed in the deposition hole. This report describes the Posiva's reference solution for the buffer moisture protection system and the bottom plate on basis of the demands and functional requirements set by long-term safety. The reference solution with structural details has been developed in research work made 2010-2011. The structural solution of the moisture protection system has not yet been tested in practice. On the bottom of the deposition hole a copper plate which protects the lowest bentonite block from the gathered water is installed straight to machined and even rock surface. The moisture protection sheet made of EPDM rubber is attached to the copper plate with an inflatable seal. The upper part of the moisture protection sheet is fixed to the collar structures of the lid which protects the deposition hole in the disposal tunnel. The main function of the moisture protection sheet is to protect bentonite blocks from the leaking water and from the influence of the air humidity at their installation stage. The leaking water is controlled by the dewatering and alarm system which has been integrated into the moisture protection liner. (orig.)

  17. Buffer capacity of biologics--from buffer salts to buffering by antibodies.

    Science.gov (United States)

    Karow, Anne R; Bahrenburg, Sven; Garidel, Patrick

    2013-01-01

    Controlling pH is essential for a variety of biopharmaceutical process steps. The chemical stability of biologics such as monoclonal antibodies is pH-dependent and slightly acidic conditions are favorable for stability in a number of cases. Since control of pH is widely provided by added buffer salts, the current study summarizes the buffer characteristics of acetate, citrate, histidine, succinate, and phosphate buffers. Experimentally derived values largely coincide with values calculated from a model that had been proposed in 1922 by van Slyke. As high concentrated protein formulations become more and more prevalent for biologics, the self-buffering potential of proteins becomes of relevance. The current study provides information on buffer characteristics for pH ranges down to 4.0 and up to 8.0 and shows that a monoclonal antibody at 50 mg/mL exhibits similar buffer capacity as 6 mM citrate or 14 mM histidine (pH 5.0-6.0). Buffer capacity of antibody solutions scales linearly with protein concentration up to more than 200 mg/mL. At a protein concentration of 220 mg/mL, the buffer capacity resembles the buffer capacity of 30 mM citrate or 50 mM histidine (pH 5.0-6.0). The buffer capacity of monoclonal antibodies is practically identical at the process relevant temperatures 5, 25, and 40°C. Changes in ionic strength of ΔI=0.15, in contrast, can alter the buffer capacity up to 35%. In conclusion, due to efficient self-buffering by antibodies in the pH range of favored chemical stability, conventional buffer excipients could be dispensable for pH stabilization of high concentrated protein solutions. Copyright © 2013 American Institute of Chemical Engineers.

  18. Two-Buffer Simulation Games

    Directory of Open Access Journals (Sweden)

    Milka Hutagalung

    2016-07-01

    Full Text Available We consider simulation games played between Spoiler and Duplicator on two Büchi automata in which the choices made by Spoiler can be buffered by Duplicator in two different buffers before she executes them on her structure. Previous work on such games using a single buffer has shown that they are useful to approximate language inclusion problems. We study the decidability and complexity and show that games with two buffers can be used to approximate corresponding problems on finite transducers, i.e. the inclusion problem for rational relations over infinite words.

  19. Fire Distribution in Peninsular Malaysia, Sumatra and Borneo in 2015 with Special Emphasis on Peatland Fires.

    Science.gov (United States)

    Miettinen, Jukka; Shi, Chenghua; Liew, Soo Chin

    2017-10-01

    In this paper, we analyze the spatio-temporal distribution of vegetation fires in Peninsular Malaysia, Sumatra, and Borneo in the severe El Niño year of 2015, concentrating on the distribution of fires between mineral soils and peatland areas, and between land cover types in peatland areas. The results reveal that 53% of all Moderate Resolution Imaging Spectroradiometer (MODIS) fire detections were recorded in peatlands that cover only 12% of the study area. However, fire occurrence in the peatland areas was highly dependent on land cover type. Pristine peat swamp forests (PSF) experienced only marginal fire activity (30 fire detections per 1000 km 2 ) compared to deforested undeveloped peatlands (831-915 fire detections per 1000 km 2 ). Our results also highlight the extreme fire vulnerability of the southern Sumatran and Bornean peatlands under strong El Niño conditions: 71% of all peatland hotspots were detected in the provinces of South Sumatra and Central Kalimantan, which contain 29% of peatlands in the study area. Degraded PSF and all deforested peatland land cover types, including managed areas, in the two provinces were severely affected, demonstrating how difficult it is to protect even managed drained agricultural areas from unwanted fires during dry periods. Our results thereby advocate rewetting and rehabilitation as the primary management option for highly fire prone degraded undeveloped peatland areas, whenever feasible, as a means to reduce fire risk during future dry episodes.

  20. Northern peatland initiation lagged abrupt increases in deglacial atmospheric CH4.

    Science.gov (United States)

    Reyes, Alberto V; Cooke, Colin A

    2011-03-22

    Peatlands are a key component of the global carbon cycle. Chronologies of peatland initiation are typically based on compiled basal peat radiocarbon (14C) dates and frequency histograms of binned calibrated age ranges. However, such compilations are problematic because poor quality 14C dates are commonly included and because frequency histograms of binned age ranges introduce chronological artefacts that bias the record of peatland initiation. Using a published compilation of 274 basal 14C dates from Alaska as a case study, we show that nearly half the 14C dates are inappropriate for reconstructing peatland initiation, and that the temporal structure of peatland initiation is sensitive to sampling biases and treatment of calibrated 14C dates. We present revised chronologies of peatland initiation for Alaska and the circumpolar Arctic based on summed probability distributions of calibrated 14C dates. These revised chronologies reveal that northern peatland initiation lagged abrupt increases in atmospheric CH4 concentration at the start of the Bølling-Allerød interstadial (Termination 1A) and the end of the Younger Dryas chronozone (Termination 1B), suggesting that northern peatlands were not the primary drivers of the rapid increases in atmospheric CH4. Our results demonstrate that subtle methodological changes in the synthesis of basal 14C ages lead to substantially different interpretations of temporal trends in peatland initiation, with direct implications for the role of peatlands in the global carbon cycle.

  1. Peatlands as a unique climatic hotspots

    Science.gov (United States)

    Slowinska, S.; Marcisz, K.; Slowinski, M. M.; Blazejczyk, K.; Lamentowicz, M.

    2017-12-01

    Peatlands are unique environments, often acting as microrefugia of various taxa. High groundwater table, organic soils, specific vegetation and topography are important determinants of their local climatic conditions. However, relations between those determinants are not stable. For example, seasonal changes in weather patterns, hydrological dynamics, and local vegetation may alter microclimate. Additionally, long-term changes are important factor, as for example overgrowing due to significant change of microclimate conditions, what in turn changes geochemical and biological processes in the peat layer. We have been investigating interactions between abiotic and biotic factors of a small Sphagnum mire (ca. 6.0 ha) for over ten years now. The mire is located in Poland in transitional temperate climate and is the only place in polish lowlands where glacial relict Betula nana occurs. Identification of local climate of the mire, its microclimatic differentiation and its influence on surroundings were objectives of the study. We recorded water level fluctuations, photosynthetically active radiation (PAR), air temperature and humidity, and peat temperature at five monitoring plots at the mire and observed significant differences between them. We also investigated Sphagnum mosses growth and testate amoeba diversity and community structure to understand biological response of those differences. We observed that local climate of the mire was significantly different from open area reference place, it was much colder especially during nights. The average minimal temperature at the height 30 cm for growing seasons 2010-2012 was 3.7oC lower there and ground frosts occurred even in the summer. The climate of the mire affected the forest directly adjacent to it, and depending on weather conditions the strength and the distance of this interaction was different. Our results show that micro-environmental changes affects on biological processes and should be taken into consideration

  2. Geomorphology and landscape organization of a northern peatland complex

    Science.gov (United States)

    Richardson, M. C.

    2012-12-01

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

  3. Resource contrast in patterned peatlands increases along a climatic gradient

    NARCIS (Netherlands)

    Eppinga, M.B.; Rietkerk, M.; Belyea, L.R.; Nilsson, M.B.; Ruiter, de P.C.; Wassen, M.J.

    2010-01-01

    Spatial patterning of ecosystems can be explained by several mechanisms. One approach to disentangling the influence of these mechanisms is to study a patterned ecosystem along a gradient of environmental conditions. This study focused on hummock–hollow patterning of peatlands. Previous models

  4. Climate-driven flushing of pore water in peatlands

    Science.gov (United States)

    Siegel, D. I.; Reeve, A. S.; Glaser, P. H.; Romanowicz, E. A.

    1995-04-01

    NORTHERN peatlands can act as either important sources or sinks for atmospheric carbon1,2. It is therefore important to understand how carbon cycling in these regions will respond to a changing climate. Existing carbon balance models for peatlands assume that fluid flow and advective mass transport are negligible at depth3,4, and that the effects of climate change should be essentially limited to the near-surface. Here we report the response of groundwater flow and porewater chemistry in the Glacial Lake Agassiz peat-lands of northern Minnesota to the regional drought cycle. Comparison of field observations and numerical simulations indicates that climate fluctuations of short duration may temporarily reverse the vertical direction of fluid flow through the peat, although this has little effect on water chemistry5. On the other hand, periods of drought persisting for at least 3-5 years produce striking changes in the chemistry of the pore water. These longer-term changes in hydrology influence the flux of nutrients and dissolved organic matter through the deeper peat, and therefore affect directly the rates of fermentation and methanogenesis, and the export of dissolved carbon compounds from the peatland.

  5. Establishing trees on cut-over peatlands in eastern Canada

    Directory of Open Access Journals (Sweden)

    J. Bussières

    2008-12-01

    Full Text Available Four major tree-planting trials on cut-over peatlands in eastern Canada were surveyed in 2002, in order to evaluate the potential use of trees in rehabilitation following horticultural peat extraction. At one of the sites, an experiment to determine the appropriate fertilisation rate for trees planted on cut-over peatlands was also conducted over several years. Tree performance was assessed by measuring survival, total height and annual growth of red maple (Acer rubrum L., tamarack (Larix laricina (Du Roi Koch., black spruce (Picea mariana (Mill. B.S.P., jack pine (Pinus banksiana Lamb. and hybrid poplar (Populus spp.. Establishment and growth of tamarack and black spruce in cut-over peatlands showed good potential when compared to performance in conventional forestry plantations. Red maple and jack pine gave poor productivity but promising survival, whilst hybrid poplar plantings failed. Adding nutrients was essential for growth but dosages above 122.5 g of 3.4N-8.3P-24.2K per tree gave no further improvement. Therefore, several different tree species can be planted to reclaim cut-over peatlands in eastern Canada, so long as the appropriate species are chosen and nutrients are provided.

  6. GHG mitigation of agricultural peatlands requires coherent policies

    DEFF Research Database (Denmark)

    Regina, Kristina; Budiman, Arif; Greve, Mogens Humlekrog

    2016-01-01

    As soon as peat soil is drained for agricultural production, the peat starts to degrade, which causes emissions to the atmosphere. In countries with large peatland areas, the GHG mitigation potential related to management of these soils is often estimated as the highest amongst the measures...

  7. IMPROVING WATER REGIME IN MLACA TĂTARILOR PEATLAND

    Directory of Open Access Journals (Sweden)

    Ionuţ Cristian Moale

    2017-07-01

    Full Text Available Following the project Restoration strategies of the deteriorated peatland ecosystems from Romania (PeatRo, it has been shown that Romania has 32 peatlands that need hydrological restoration taking into account the increasing of human activities and changes in land use. These peatlands are distributed in the Alpine region (30 and in the Continental region (2. In this paper, we started from the assumption that the evapotranspiration process can be reduced by decreasing the spread of colonizing species Betula pendula and Rhamnus frangula, in order to reduce the evapotranspiration rate. To establish the conditions for hydrology restoration, we used a conceptual model applied to the peatland functioning in order to quantify the water inflows (from runoff and rainfall and outflows (overbank outflows, by evaporation, by colonizing species transpiration. To estimate the rate of evapotranspiration for these species, we used in the model as input data: height and diameter of the individuals, the number of individuals, the leaf area of individual, wind speed, temperature, humidity, the number of sun hours / day, the surface of the water table. Model results show that evapotranspiration process can be reduced after implementation of specific restoration activities, demonstrating a real improvement on water regime.

  8. Carbon storage in forests and peatlands of Russia

    Science.gov (United States)

    V.A. Alexeyev; R.A. Birdsey; [Editors

    1998-01-01

    Contains information about carbon storage in the vegetation, soils, and peatlands of Russia. Estimates of carbon storage in forests are derived from statistical data from the 1988 national forest inventory of Russia and from other sources. Methods are presented for converting data on timber stock into phytomass of tree stands, and for estimating carbon storage in...

  9. Peatland Ecosystem Processes in the Maritime Antarctic During Warm Climates.

    Science.gov (United States)

    Loisel, Julie; Yu, Zicheng; Beilman, David W; Kaiser, Karl; Parnikoza, Ivan

    2017-09-27

    We discovered a 50-cm-thick peat deposit near Cape Rasmussen (65.2°S), in the maritime Antarctic. To our knowledge, while aerobic 'moss banks' have often been examined, waterlogged 'peatlands' have never been described in this region before. The waterlogged system is approximately 100 m 2 , with a shallow water table. Surface vegetation is dominated by Warnstorfia fontinaliopsis, a wet-adapted moss commonly found in the Antarctic Peninsula. Peat inception was dated at 2750 cal. BP and was followed by relatively rapid peat accumulation (~0.1 cm/year) until 2150 cal. BP. Our multi-proxy analysis then shows a 2000-year-long stratigraphic hiatus as well as the recent resurgence of peat accumulation, sometime after 1950 AD. The existence of a thriving peatland at 2700-2150 cal. BP implies regionally warm summer conditions extending beyond the mid-Holocene; this finding is corroborated by many regional records showing moss bank initiation and decreased sea ice extent during this time period. Recent peatland recovery at the study site (maritime Antarctic region may promote a more peatland-rich landscape in the future.

  10. Beaver Mediated Water Table Dynamics in Mountain Peatlands

    Science.gov (United States)

    Karran, D. J.; Westbrook, C.; Bedard-Haughn, A.

    2016-12-01

    Water table dynamics play an important role in the ecological and biogeochemical processes that regulate carbon and water storage in peatlands. Beaver are common in these habitats and the dams they build have been shown to raise water tables in other environments. However, the impact of beaver dams in peatlands, where water tables rest close to the surface, has yet to be determined. We monitored a network of 50 shallow wells in a Canadian Rocky Mountain peatland for 6 years. During this period, a beaver colony was maintaining a number of beaver ponds for four years until a flood event removed the colony from the area and breached some of the dams. Two more years of data were collected after the flood event to assess whether the dams enhanced groundwater storage. Beaver dams raised water tables just as they do in other environments. Furthermore, water tables within 100 meters of beaver dams were more stable than those further away and water table stability overall was greater before the flood event. Our results suggest the presence/absence of beaver in peatlands has implications for groundwater water storage and overall system function.

  11. Decreased summer water table depth affects peatland vegetation

    NARCIS (Netherlands)

    Breeuwer, A.J.G.; Robroek, B.J.M.; Limpens, J.; Heijmans, M.M.P.D.; Schouten, M.G.C.; Berendse, F.

    2009-01-01

    Climate change can be expected to increase the frequency of summer droughts and associated low water tables in ombrotrophic peatlands. We studied the effects of periodic water table drawdown in a mesocosm experiment. Mesocosms were collected in Southern Sweden, and subsequently brought to an

  12. Modelling Peatland Hydrology: Three cases from Northern Europe

    NARCIS (Netherlands)

    Querner, E.P.; Mioduszewski, W.; Povilaitis, A.; Slesicka, A.

    2010-01-01

    Many of the peatlands that used to extend over large parts of Northern Europe have been reclaimed for agriculture. Human influence continues to have a major impact on the hydrology of those that remain, affecting river flow and groundwater levels. In order to understand this hydrology it is

  13. Polygonal patterned peatlands of the White Sea islands

    Science.gov (United States)

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

    2018-03-01

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

  14. The role of fire in UK peatland and moorland management

    NARCIS (Netherlands)

    Davies, G.M.; Kettridge, Nicholas; Stoof, Cathelijne R.; Gray, Alan; Ascoli, Davide; Fernandes, Paulo M.; Marrs, Rob; Allen, Katherine A.; Doerr, Stefan H.; Clay, Gareth D.; McMorrow, Julia; Vandvik, Vigdis

    2016-01-01

    Fire has been used for centuries to generate and manage some of the UK’s cultural landscapes. Despite its complex role in the ecology of UK peatlands and moorlands, there has been a trend of simplifying the narrative around burning to present it as an only ecologically damaging practice. That

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

    Science.gov (United States)

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

    2015-05-01

    Vegetation removal with fire can alter the thermal regime of the land surface, leading to significant changes in biogeochemistry (e.g. carbon cycling) and soil hydrology. In the UK, large expanses of carbon-rich upland environments are managed to encourage increased abundance of red grouse (Lagopus lagopus scotica) by rotational burning of shrub vegetation. To date, though, there has not been any consideration of whether prescribed vegetation burning on peatlands modifies the thermal regime of the soil mass in the years after fire. In this study thermal regime was monitored across 12 burned peatland soil plots over an 18-month period, with the aim of (i) quantifying thermal dynamics between burned plots of different ages (from post burning), and (ii) developing statistical models to determine the magnitude of thermal change caused by vegetation management. Compared to plots burned 15 + years previously, plots recently burned (management effects. Temperatures measured in soil plots burned vegetation regrows. Our findings that prescribed peatland vegetation burning alters soil thermal regime should provide an impetus for further research to understand the consequences of thermal regime change for carbon processing and release, and hydrological processes, in these peatlands. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Calculating carbon budgets of wind farms on Scottish peatlands

    Directory of Open Access Journals (Sweden)

    D.R. Nayak

    2010-04-01

    Full Text Available The reliability of calculation methods for the carbon emission savings to be achieved in Scotland by replacing power generated from fossil fuels (and other more conventional sources with that produced by large-scale wind farm developments is a cause for concern, largely in relation to wind farms sited on peatlands. Scottish Government policy is to deliver renewable energy without environmental harm, and to meet biodiversity objectives including the conservation of designated wildlife sites and important habitats such as peatlands. The implications for carbon emissions of developing a wind farm are, therefore, just one aspect of the suite of considerations that the planning system takes into account. This paper presents a simple methodology for prospectively calculating the potential carbon emission savings to be realised by developing wind farms on peatland, forestland or afforested peatland. The total carbon emission savings of an individual wind farm are estimated by accounting emissions from the power source that will be replaced by wind power against: loss of carbon due to production, transportation, erection, operation and dismantling of the wind farm components (the infrastructure overhead; loss of carbon due to backup power generation; loss of carbon stored in peat and forest; loss of carbon-fixing potential of peatland and forest; and carbon savings due to habitat improvement. Most of the carbon losses are determined by national infrastructure, but those from peat soil and plants are influenced by site selection and management practices. The extent of drainage around each constructed element of the wind farm is a major factor for greenhouse gas emissions. Consideration of an example site with a low extent of drainage, where management practices that minimise net carbon losses (e.g. undrained floating roads, habitat improvement and site restoration on decommissioning were used indicates that emissions from the soil and plants may cancel

  17. Methanogenesis limitations in degraded peatlands after their hydrological restoration

    Science.gov (United States)

    Urbanová, Zuzana

    2017-04-01

    Peatlands are ecosystems that can have a high degree of carbon sequestration due to CO2 fixation and low decomposition rates, but on the other hand, they are a source of CH4. Past drainage or mining can disturb these natural functions with rewetting being the main method used to bring back their original ecosystem properties. Methanogenic community composition and its activity seems to be very sensitive to environmental changes and therefore its limited activity after restoration can reflect the not fully restored functioning of the microbial community and its processes in the rewetted peatlands. To find the cause for this methanogenesis limitation we determined the abundance and composition of the methanogenic community and methane potential production in pristine, long-term drained and rewetted bogs and spruce swamp forests (SSF) in the Šumava Mountains (Czech Republic), using high-throughput barcoded sequencing, qPCR and anaerobic incubation of peat samples in relation to peat biochemical properties. Long-term drainage led to a strongly reduced diversity, abundance and activity of the methanogenic community in both peatland types. In restored sites, methanogenic abundance and community composition reached a pristine like state, however their activity measured as CH4 production remained as low as in drained sites. Substrate limitation was expected; therefore we further added different substrates during anaerobic incubation of the peat samples. In addition to glucose and ethanol, we added natural complex substrates from peatland plants (sedges, Sphagnum) to simulate the effect of the spreading of peatland species and their litter on methanogenic activity. The results unambiguously confirmed the limitation of methanogens by substrate availability due to the previous long-term drainage and strongly decomposed peat. The addition of natural substrates led to an increase in CH4 production, which was close to values in pristine sites. The limited CH4 production

  18. Using fractional order method to generalize strengthening generating operator buffer operator and weakening buffer operator

    OpenAIRE

    Wu, L.; Liu, S.; Yang, Yingjie

    2016-01-01

    Traditional integer order buffer operator is extended to fractional order buffer operator, the corresponding relationship between the weakening buffer operator and the strengthening buffer operator is revealed. Fractional order buffer operator not only can generalize the weakening buffer operator and the strengthening buffer operator, but also realize tiny adjustment of buffer effect. The effectiveness of GM(1,1) with the fractional order buffer operator is validated by six cases.

  19. Mechanisms of buffer therapy resistance.

    Science.gov (United States)

    Bailey, Kate M; Wojtkowiak, Jonathan W; Cornnell, Heather H; Ribeiro, Maria C; Balagurunathan, Yoganand; Hashim, Arig Ibrahim; Gillies, Robert J

    2014-04-01

    Many studies have shown that the acidity of solid tumors contributes to local invasion and metastasis. Oral pH buffers can specifically neutralize the acidic pH of tumors and reduce the incidence of local invasion and metastatic formation in multiple murine models. However, this effect is not universal as we have previously observed that metastasis is not inhibited by buffers in some tumor models, regardless of buffer used. B16-F10 (murine melanoma), LL/2 (murine lung) and HCT116 (human colon) tumors are resistant to treatment with lysine buffer therapy, whereas metastasis is potently inhibited by lysine buffers in MDA-MB-231 (human breast) and PC3M (human prostate) tumors. In the current work, we confirmed that sensitive cells utilized a pH-dependent mechanism for successful metastasis supported by a highly glycolytic phenotype that acidifies the local tumor microenvironment resulting in morphological changes. In contrast, buffer-resistant cell lines exhibited a pH-independent metastatic mechanism involving constitutive secretion of matrix degrading proteases without elevated glycolysis. These results have identified two distinct mechanisms of experimental metastasis, one of which is pH-dependent (buffer therapy sensitive cells) and one which is pH-independent (buffer therapy resistant cells). Further characterization of these models has potential for therapeutic benefit. Copyright © 2014 Neoplasia Press, Inc. Published by Elsevier Inc. All rights reserved.

  20. Greenhouse impact of Finnish peatlands 1900-2100

    Energy Technology Data Exchange (ETDEWEB)

    Laine, J; Minkkinen, K [Helsinki Univ. (Finland). Dept. of Ecology; Tolonen, K; Turunen, J [Joensuu Univ. (Finland). Dept. of Biology; Martikainen, P; Nykaenen, H [National Public Health Inst. Kuopio (Finland). Dept. of Environmental Microbiology; Sinisalo, J; Savolainen, I [VTT Energy, Espoo (Finland)

    1997-12-31

    Northern peatlands are significant in regulating the global climate. While sequestering carbon dioxide (CO{sub 2}, ca. 100 Tg C a{sup -} {sup 1}), these peatlands release cat 24-39 Tg methane (CH{sub 4}) annually to the atmosphere. This is 5-15 % of the annual anthropogenic and 10-35 % of the annual natural CH4 emissions to the atmosphere. The greenhouse gas balance of peatlands may change as a consequence of water level drawdown after land use change, or if summers become warmer and drier, as has been predicted for high latitudes after climatic warming. Currently, some 15 million hectares of northern peatlands and other wetlands have been drained for forestry. More than 90 % of this area is found in Scandinavia and the former Soviet Union. The area drained annually has, however, been declining during the last two decades and, in Finland for instance the annual drained area of nearly 300 000 hectares in the late 1960`s has decreased to cat 35 000 hectares in the early 1990`s. Radiative forcing is the change in the radiative energy balance at the tropopause and it is the driving force behind the greenhouse effect. It is a common quantity for most greenhouse gases and takes into account the dynamics of the greenhouse impact. Radiative forcing model was used to compute the greenhouse impact of the drainage of the peatlands, combining the effects of CO{sub 2} and CH4 balances; N{sub 2}O was not included in the calculations because its contribution is minor. (14 refs.)

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

    Science.gov (United States)

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

    2016-11-01

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

  2. Greenhouse impact of Finnish peatlands 1900-2100

    Energy Technology Data Exchange (ETDEWEB)

    Laine, J.; Minkkinen, K. [Helsinki Univ. (Finland). Dept. of Ecology; Tolonen, K.; Turunen, J. [Joensuu Univ. (Finland). Dept. of Biology; Martikainen, P.; Nykaenen, H. [National Public Health Inst. Kuopio (Finland). Dept. of Environmental Microbiology; Sinisalo, J.; Savolainen, I. [VTT Energy, Espoo (Finland)

    1996-12-31

    Northern peatlands are significant in regulating the global climate. While sequestering carbon dioxide (CO{sub 2}, ca. 100 Tg C a{sup -} {sup 1}), these peatlands release cat 24-39 Tg methane (CH{sub 4}) annually to the atmosphere. This is 5-15 % of the annual anthropogenic and 10-35 % of the annual natural CH4 emissions to the atmosphere. The greenhouse gas balance of peatlands may change as a consequence of water level drawdown after land use change, or if summers become warmer and drier, as has been predicted for high latitudes after climatic warming. Currently, some 15 million hectares of northern peatlands and other wetlands have been drained for forestry. More than 90 % of this area is found in Scandinavia and the former Soviet Union. The area drained annually has, however, been declining during the last two decades and, in Finland for instance the annual drained area of nearly 300 000 hectares in the late 1960`s has decreased to cat 35 000 hectares in the early 1990`s. Radiative forcing is the change in the radiative energy balance at the tropopause and it is the driving force behind the greenhouse effect. It is a common quantity for most greenhouse gases and takes into account the dynamics of the greenhouse impact. Radiative forcing model was used to compute the greenhouse impact of the drainage of the peatlands, combining the effects of CO{sub 2} and CH4 balances; N{sub 2}O was not included in the calculations because its contribution is minor. (14 refs.)

  3. Annual carbon balance of a peatland 10 yr following restoration

    Directory of Open Access Journals (Sweden)

    M. Strack

    2013-05-01

    Full Text Available Undisturbed peatlands represent long-term net sinks of carbon; however, peat extraction converts these systems into large and persistent sources of greenhouse gases. Although rewetting and restoration following peat extraction have taken place over the last several decades, very few studies have investigated the longer term impact of this restoration on peatland carbon balance. We determined the annual carbon balance of a former horticulturally-extracted peatland restored 10 yr prior to the study and compared these values to the carbon balance measured at neighboring unrestored and natural sites. Carbon dioxide (CO2 and methane (CH4 fluxes were measured using the chamber technique biweekly during the growing season from May to October 2010 and three times over the winter period. Dissolved organic carbon (DOC export was measured from remnant ditches in the unrestored and restored sites. During the growing season the restored site had greater uptake of CO2 than the natural site when photon flux density was greater than 1000 μmol m−2 s−1, while the unrestored site remained a source of CO2. Ecosystem respiration was similar between natural and restored sites, which were both significantly lower than the unrestored site. Methane flux remained low at the restored site except from open water pools, created as part of restoration, and remnant ditches. Export of DOC during the growing season was 5.0 and 28.8 g m−2 from the restored and unrestored sites, respectively. Due to dry conditions during the study year all sites acted as net carbon sources with annual balance of the natural, restored and unrestored sites of 250.7, 148.0 and 546.6 g C m−2, respectively. Although hydrological conditions and vegetation community at the restored site remained intermediate between natural and unrestored conditions, peatland restoration resulted in a large reduction in annual carbon loss from the system resulting in a carbon balance more similar to a natural

  4. Brown carbon aerosols from burning of boreal peatlands: microphysical properties, emission factors, and implications for direct radiative forcing

    Science.gov (United States)

    Rajan K. Chakrabarty; Madhu Gyawali; Reddy L. N. Yatavelli; Apoorva Pandey; Adam C. Watts; Joseph Knue; Lung-Wen A. Chen; Robert R. Pattison; Anna Tsibart; Vera Samburova; Hans Moosmuller

    2016-01-01

    The surface air warming over the Arctic has been almost twice as much as the global average in recent decades. In this region, unprecedented amounts of smoldering peat fires have been identified as a major emission source of climate-warming agents. While much is known about greenhouse gas emissions from these fires, there is a knowledge gap on the nature of particulate...

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

    Science.gov (United States)

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

    2016-04-01

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

  6. Peatland Bryophytes in a Changing Environment : Ecophysiological Traits and Ecosystem Function

    OpenAIRE

    Granath, Gustaf

    2012-01-01

    Peatlands are peat forming ecosystems in which not fully decomposed plant material builds up the soil. The sequestration of carbon into peat is mainly associated with the bryophyte genus Sphagnum (peat mosses), which dominate and literally form most peatlands. The responses of Sphagnum to environmental change help us to understand peatland development and function and to predict future changes in a rapidly changing world. In this thesis, the overarching aim was to use ecophysiological traits ...

  7. Evaluating the use of testate amoebae for palaeohydrological reconstruction in permafrost peatlands

    OpenAIRE

    Swindles, Graeme T.; Amesbury, Matthew J.; Turner, T. Edward; Carrivick, Jonathan L.; Woulds, Clare; Raby, Cassandra; Mullan, Donal; Roland, Thomas P.; Galloway, Jennifer M.; Parry, Lauren; Kokfelt, Ulla; Garneau, Michelle; Charman, Dan J.; Holden, Joseph

    2015-01-01

    The melting of high-latitude permafrost peatlands is a major concern due to a potential positive feedback on global climate change. We examine the ecology of testate amoebae in permafrost peatlands, based on sites in Sweden (~ 200 km north of the Arctic Circle). Multivariate statistical analysis confirms that water-table depth and moisture content are the dominant controls on the distribution of testate amoebae, corroborating the results from studies in mid-latitude peatlands. We present a ne...

  8. The effect of peatland drainage and restoration on Odonata species richness and abundance

    OpenAIRE

    Elo, Merja; Penttinen, Jouni; Kotiaho, Janne Sakari

    2015-01-01

    Background Restoration aims at reversing the trend of habitat degradation, the major threat to biodiversity. In Finland, more than half of the original peatland area has been drained, and during recent years, restoration of some of the drained peatlands has been accomplished. Short-term effects of the restoration on peatland hydrology, chemistry and vegetation are promising but little is known about how other species groups apart from vascular plants and bryophytes respond to restoration effo...

  9. Electrodialysis operation with buffer solution

    Science.gov (United States)

    Hryn, John N [Naperville, IL; Daniels, Edward J [Orland Park, IL; Krumdick, Greg K [Crete, IL

    2009-12-15

    A new method for improving the efficiency of electrodialysis (ED) cells and stacks, in particular those used in chemical synthesis. The process entails adding a buffer solution to the stack for subsequent depletion in the stack during electrolysis. The buffer solution is regenerated continuously after depletion. This buffer process serves to control the hydrogen ion or hydroxide ion concentration so as to protect the active sites of electrodialysis membranes. The process enables electrodialysis processing options for products that are sensitive to pH changes.

  10. A decade of boreal rich fen greenhouse gas fluxes in response to natural and experimental water table variability

    Science.gov (United States)

    Olefeldt, David; Euskirchen, Eugénie S.; Harden, Jennifer W.; Kane, Evan S.; McGuire, A. David; Waldrop, Mark P.; Turetsky, Merritt R.

    2017-01-01

    Rich fens are common boreal ecosystems with distinct hydrology, biogeochemistry and ecology that influence their carbon (C) balance. We present growing season soil chamber methane emission (FCH4), ecosystem respiration (ER), net ecosystem exchange (NEE) and gross primary production (GPP) fluxes from a 9-years water table manipulation experiment in an Alaskan rich fen. The study included major flood and drought years, where wetting and drying treatments further modified the severity of droughts. Results support previous findings from peatlands that drought causes reduced magnitude of growing season FCH4, GPP and NEE, thus reducing or reversing their C sink function. Experimentally exacerbated droughts further reduced the capacity for the fen to act as a C sink by causing shifts in vegetation and thus reducing magnitude of maximum growing season GPP in subsequent flood years by ~15% compared to control plots. Conversely, water table position had only a weak influence on ER, but dominant contribution to ER switched from autotrophic respiration in wet years to heterotrophic in dry years. Droughts did not cause inter-annual lag effects on ER in this rich fen, as has been observed in several nutrient-poor peatlands. While ER was dependent on soil temperatures at 2 cm depth, FCH4 was linked to soil temperatures at 25 cm. Inter-annual variability of deep soil temperatures was in turn dependent on wetness rather than air temperature, and higher FCH4 in flooded years was thus equally due to increased methane production at depth and decreased methane oxidation near the surface. Short-term fluctuations in wetness caused significant lag effects on FCH4, but droughts caused no inter-annual lag effects on FCH4. Our results show that frequency and severity of droughts and floods can have characteristic effects on the exchange of greenhouse gases, and emphasize the need to project future hydrological regimes in rich fens.

  11. Microclimate of Developed Peatland of the Mega Rice Project in Central Kalimantan

    Directory of Open Access Journals (Sweden)

    Adi Jaya

    2010-01-01

    Full Text Available In Indonesia peatland covers an area of 16 to 27 Mha and this ecosystem is vitally linked toenvironmental and conservation issues, as well as its economic value for human survival. These peatlands are,however, the subject of various land use pressures, including forestry, agriculture, energy and horticulture. A fieldstudy was carried out 6 years after the end of failed peatland development project shows that inappropriate andunsustainable forms of peatland management have resulted in degradation of the natural forest vegetation, draw-downof the peat water table, increase of peat surface and air temperatures and recurrent surface and ground fires. Implicationsof microclimate for possible restoration options

  12. Large carbon dioxide fluxes from headwater boreal and sub-boreal streams.

    Science.gov (United States)

    Venkiteswaran, Jason J; Schiff, Sherry L; Wallin, Marcus B

    2014-01-01

    Half of the world's forest is in boreal and sub-boreal ecozones, containing large carbon stores and fluxes. Carbon lost from headwater streams in these forests is underestimated. We apply a simple stable carbon isotope idea for quantifying the CO2 loss from these small streams; it is based only on in-stream samples and integrates over a significant distance upstream. We demonstrate that conventional methods of determining CO2 loss from streams necessarily underestimate the CO2 loss with results from two catchments. Dissolved carbon export from headwater catchments is similar to CO2 loss from stream surfaces. Most of the CO2 originating in high CO2 groundwaters has been lost before typical in-stream sampling occurs. In the Harp Lake catchment in Canada, headwater streams account for 10% of catchment net CO2 uptake. In the Krycklan catchment in Sweden, this more than doubles the CO2 loss from the catchment. Thus, even when corrected for aquatic CO2 loss measured by conventional methods, boreal and sub-boreal forest carbon budgets currently overestimate carbon sequestration on the landscape.

  13. Controls on moss evaporation in a boreal black spruce forest

    NARCIS (Netherlands)

    Heijmans, M.M.P.D.; Arp, W.J.; Chapin, F.S.

    2004-01-01

    [1] Mosses are an important component of the boreal forest, but little is known about their contribution to ecosystem carbon, water, and energy exchange. We studied the role of mosses in boreal forest evapotranspiration by conducting two experiments in a black spruce forest in Fairbanks, Alaska.

  14. Rock, Paper, Protest: The Fight for the Boreal Forest

    Science.gov (United States)

    Gunz, Sally; Whittaker, Linda

    2016-01-01

    Canada's boreal forests are second only to the Amazon in producing life-giving oxygen and providing a habitat for thousands of species, from the large woodland caribou to the smallest organisms. The boreal forests are the lifeblood of many Aboriginal communities and the thousands of workers, Aboriginal and non-Aboriginal, who harvest and process…

  15. Macroinvertebrate community assembly in pools created during peatland restoration

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  16. Paludiculture on marginal lands - sustainable use of wet peatlands

    Science.gov (United States)

    Oehmke, Claudia; Dahms, Tobias; Wichmann, Sabine; Wichtmann, Wendelin

    2017-04-01

    Peatlands are marginal lands. If they are drained, they show a short initial productive period. Soil degradation due to peat oxidation leads to numerous problems which increasingly restrict agricultural use and cause significant environmental impacts such as greenhouse gas emissions and eutrophication and thereby produce high external costs. Worldwide greenhouse gas emissions from drained peatlands have a significant share ( 10%) in the emissions from agriculture, forestry and other land use (AFOLU) sectors (Smith et al. 2014). In Germany they contribute more than 35% to the total emissions from agriculture (agricultural sector and cropland and grassland management) (UBA 2016). Rewetting drained peatlands can significantly reduce environmental problems caused by peatland drainage. Continuation of agricultural use with adapted crops and machinery, so called paludiculture (Latin ‚palus' = swamp) stops further degradation, maintains the peat body, reduces climate change mitigation and produces renewable fuels and raw materials. Fen and bog soils are suitable for various different paludicultures. The biomass of Sphagnum (sphagnum farming) cultivated on cut-over bogs or degraded bog grasslands can be used as raw material for horticultural growing media. Flood-tolerant and productive plant species like Common Reed, Reed Canary Grass, Cattail, Black Alder and different Sedge species are suitable for paludiculture on fen soils. Biomass utilization ranges from traditional forms, like fodder production or the use of Common Reed as roof thatch, to new utilization options, that includes biomass use for heat generation, co-subtrates for biorefineries or construction and insulation products. The above-ground biomass of one hectare Common Reed (winter yield=8 t DM) equates to an energy content of 3,000 litre heating oil. A district heating plant (800 kW) in NE Germany demonstrates the feasibility of using biomass from wet fen meadows for local heat generation. Moreover, tests

  17. Peatland Microbial Carbon Use Under Warming using Isotopic Fractionation

    Science.gov (United States)

    Gutknecht, J.

    2016-12-01

    Peatlands are a critical natural resource, especially in their role as carbon sinks. Most of the world's peatlands are located in Northern ecosystems where the climate is changing at a rapid pace, and there is great interest and concern with how climate change will influence them. Although studies regarding the response of peatlands to climate change have emerged, the microbial mediation of C cycling in these systems is still less well understood. In this study, 13CPLFA analysis was used to characterize the microbial community and it's carbon use at the Spruce and Peatland Responses Under Climatic and Environmental Change (SPRUCE) Project. The SPRUCE project is an extensive study of the response of peatlands to climatic manipulation in the Marcell Experimental Forest in northern Minnesota. Heating rods were installed in peatland plots where peat is being warmed at several levels including ambient, +2.5, +4.5, +6.75, and +9 degrees Celsius, at a depth of 3 meters, beginning July of 2014. Samples were taken June 2014, September 2014, and June 2015, throughout the depth profile. We found very high microbial, and especially fungal growth at shallow depths, owing in part to the influence of fungal-like lipids present in Sphagnum stems, and in part to dense mycorrhizal colonization in shrub and tree species. Isotopic data shows that microbial biomass has an enriched δ13C lower in the peat profile, indicating as expected that microbes at depth utilize older carbon or carbon more enriched in 13C. The increase over depth in the δ13C signature may also reflect the increased dominance of pre-industrial carbon that is more enriched in 13C. In this early period of warming we did not see clear effects of warming, either due to the highly heterogeneous microbial growth across the bog, or to the short term deep warming only. We expect that with the initiation of aboveground warming in July 2016, warming will begin to show stronger effects on microbial C cycling.

  18. Macroinvertebrate community assembly in pools created during peatland restoration

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Lee E., E-mail: l.brown@leeds.ac.uk; Ramchunder, Sorain J.; Beadle, Jeannie M.; Holden, Joseph

    2016-11-01

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

  19. Heat conductivity of buffer materials

    International Nuclear Information System (INIS)

    Boergesson, L.; Fredrikson, Anders; Johannesson, L.E.

    1994-11-01

    The report deals with the thermal conductivity of bentonite based buffer materials. An improved technique for measuring the thermal conductivity of buffer materials is described. Measurements of FLAC calculations applying this technique have led to a proposal of how standardized tests should be conducted and evaluated. The thermal conductivity of bentonite with different void ratio and degree of water saturation has been determined in the following different ways: * Theoretically according to three different investigations by other researchers. * Laboratory measurements with the proposed method. * Results from back-calculated field tests. Comparison and evaluation showed that these results agreed very well, when the buffer material was almost water saturated. However, the influence of the degree of saturation was not very well predicted with the theoretical methods. Furthermore, the field tests showed that the average thermal conductivity in situ of buffer material (compacted to blocks) with low degree of water saturation was lower than expected from laboratory tests. 12 refs, 29 figs, 11 tabs

  20. Buffers and vegetative filter strips

    Science.gov (United States)

    Matthew J. Helmers; Thomas M. Isenhart; Michael G. Dosskey; Seth M. Dabney

    2008-01-01

    This chapter describes the use of buffers and vegetative filter strips relative to water quality. In particular, we primarily discuss the herbaceous components of the following NRCS Conservation Practice Standards.

  1. Programmable pH buffers

    Science.gov (United States)

    Gough, Dara Van; Huber, Dale L.; Bunker, Bruce C.; Roberts, Mark E.

    2017-01-24

    A programmable pH buffer comprises a copolymer that changes pK.sub.a at a lower critical solution temperature (LCST) in water. The copolymer comprises a thermally programmable polymer that undergoes a hydrophobic-to-hydrophilic phase change at the LCST and an electrolytic polymer that exhibits acid-base properties that are responsive to the phase change. The programmable pH buffer can be used to sequester CO.sub.2 into water.

  2. Boreal Forests of Kamchatka: Structure and Composition

    OpenAIRE

    Eichhorn, Markus P.

    2010-01-01

    Central Kamchatka abounds in virgin old-growth boreal forest, formed primarily by Larix cajanderi and Betula platyphylla in varying proportions. A series of eight 0.25–0.30 ha plots captured the range of forests present in this region and their structure is described. Overall trends in both uplands and lowlands are for higher sites to be dominated by L. cajanderi with an increasing component of B. platyphylla with decreasing altitude. The tree line on wet sites is commonly formed by mono-domi...

  3. Rating a Wildfire Mitigation Strategy with an Insurance Premium: A Boreal Forest Case Study

    Directory of Open Access Journals (Sweden)

    Georgina Rodriguez-Baca

    2016-05-01

    Full Text Available Risk analysis entails the systematic use of historical information to determine the frequency, magnitude and effects of unexpected events. Wildfire in boreal North America is a key driver of forest dynamics and may cause very significant economic losses. An actuarial approach to risk analysis based on cumulative probability distributions was developed to reduce the adverse effects of wildfire. To this effect, we developed spatially explicit landscape models to simulate the interactions between harvest, fire and forest succession over time in a boreal forest of eastern Canada. We estimated the amount of reduction of timber harvest necessary to build a buffer stock of sufficient size to cover fire losses and compared it to an insurance premium estimated in units of timber volume from the probability of occurrence and the amount of damage. Overall, the timber harvest reduction we applied was much more costly than the insurance premium even with a zero interest rate. This is due to the fact that the insurance premium is directly related to risk while the timber harvest reduction is not and, as a consequence, is much less efficient. These results, especially the comparison with a standard indicator such as an insurance premium, have useful implications at the time of choosing a mitigation strategy to protect timber supplies against risk without overly diminishing the provision of services from the forest. They are also promoting the use of insurance against disastrous events in forest management planning.

  4. Effects of peatland drainage management on peak flows

    OpenAIRE

    C. E. Ballard; N. McIntyre; H. S. Wheater

    2011-01-01

    Open ditch drainage has historically been a common land management practice in upland blanket peats, particularly in the UK. However, peatland drainage is now generally considered to have adverse effects on the upland environment, including increased peak flows. As a result, drain blocking has become a common management strategy in the UK over recent years, although there is only anecdotal evidence to suggest that this might decrease peak flows. The change in the hydrologica...

  5. Design of Spillway Structures of Peatland Rewetting systems

    Directory of Open Access Journals (Sweden)

    Sainov Mihail Petrovich

    2014-03-01

    Full Text Available In summer 2010 drought and heat weather cause numerous peat fires. During two months Moscow was shrouded in acid smoke. To prevent such situations government of Moscow region decided to rewet previously drained peatlands. Peatland rewetting systems can be divided into two types. The first type is watering system based on previously used drainage system. The main idea of this method is rising of groundwater levels with the help of special water retaining constructions installed in drainage canals. The design of water receivers allows keeping up water level in canals and draining excesses. There are two types of water receivers: dock-type water receiver and water receiver as a portal to the gate. The choice of one or another type of water receiver depends on the canal depth. If it is less than 1.5 m, we apply portal construction. At the depth of more than 1.5 m the mine water receiver is more suitable. The second way of watering previously drained peatlands is the creation of ponds, dams on streams and small rivers. Special discharge structures increase water level in the river upstream. In downstream water level rises due to the redistribution of the flow. As a result, the groundwater level rises and peat become watered. There are two types of spillway structures: with direct overflow wall and labyrinth overflow wall. Structure with direct overflow wall is applicable on small rivers. In narrow alignments with high consumptions it is better to use another type of weir. As output it is necessary to notice that all constructions used in peatlands watering were designed as simple and reliable as possible. It is so because unpredictable weather conditions can cause beyond the design flows so weirs must have necessary reserve of passing costs.

  6. Carbon storage and long-term rate of accumulation in high-altitude Andean peatlands of Bolivia

    Science.gov (United States)

    J.A. Hribljan; D.J. Cooper; J. Sueltenfuss; E.C. Wolf; K.A. Heckman; Erik Lilleskov; R.A. Chimner

    2015-01-01

    The high-altitude (4,500+ m) Andean mountain range of north-western Bolivia contains many peatlands. Despite heavy grazing pressure and potential damage from climate change, little is known about these peatlands. Our objective was to quantify carbon pools, basal ages and long-term peat accumulation rates in peatlands in two areas of the arid puna ecoregion of Bolivia:...

  7. Palaeoecological data as a tool to predict possible future vegetation changes in the boreal forest zone of European Russia: a case study from the Central Forest Biosphere Reserve

    Science.gov (United States)

    Novenko, E. Yu; Tsyganov, A. N.; Olchev, A. V.

    2018-01-01

    New multi-proxy records (pollen, testate amoebae, and charcoal) were applied to reconstruct the vegetation dynamics in the boreal forest area of the southern part of Valdai Hills (the Central Forest Biosphere Reserve) during the Holocene. The reconstructions of the mean annual temperature and precipitation, the climate moisture index (CMI), peatland surface moisture, and fire activity have shown that climate change has a significant impact on the boreal forests of European Russia. Temperature growth and decreased moistening during the warmest phases of the Holocene Thermal Maximum in 7.0-6.2 ka BP and 6.0-5.5 ka BP and in the relatively warm phase in 3.4-2.5 ka BP led to structural changes in plant communities, specifically an increase in the abundance of broadleaf tree species in forest stands and the suppression of Picea. The frequency of forest fires was higher in that period, and it resulted in the replacement of spruce forests by secondary stands with Betula and Pinus. Despite significant changes in the climatic parameters projected for the 21st century using even the optimistic RCP2.6 scenario, the time lag between climate changes and vegetation responses makes any catastrophic vegetation disturbances (due to natural reasons) in the area in the 21st century unlikely.

  8. Global peatland initiation driven by regionally asynchronous warming.

    Science.gov (United States)

    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.

  9. Neotropical peatland methane emissions along a vegetation and biogeochemical gradient.

    Science.gov (United States)

    Winton, R Scott; Flanagan, Neal; Richardson, Curtis J

    2017-01-01

    Tropical wetlands are thought to be the most important source of interannual variability in atmospheric methane (CH4) concentrations, yet sparse data prevents them from being incorporated into Earth system models. This problem is particularly pronounced in the neotropics where bottom-up models based on water table depth are incongruent with top-down inversion models suggesting unaccounted sinks or sources of CH4. The newly documented vast areas of peatlands in the Amazon basin may account for an important unrecognized CH4 source, but the hydrologic and biogeochemical controls of CH4 dynamics from these systems remain poorly understood. We studied three zones of a peatland in Madre de Dios, Peru, to test whether CH4 emissions and pore water concentrations varied with vegetation community, soil chemistry and proximity to groundwater sources. We found that the open-canopy herbaceous zone emitted roughly one-third as much CH4 as the Mauritia flexuosa palm-dominated areas (4.7 ± 0.9 and 14.0 ± 2.4 mg CH4 m-2 h-1, respectively). Emissions decreased with distance from groundwater discharge across the three sampling sites, and tracked changes in soil carbon chemistry, especially increased soil phenolics. Based on all available data, we calculate that neotropical peatlands contribute emissions of 43 ± 11.9 Tg CH4 y-1, however this estimate is subject to geographic bias and will need revision once additional studies are published.

  10. Neotropical peatland methane emissions along a vegetation and biogeochemical gradient.

    Directory of Open Access Journals (Sweden)

    R Scott Winton

    Full Text Available Tropical wetlands are thought to be the most important source of interannual variability in atmospheric methane (CH4 concentrations, yet sparse data prevents them from being incorporated into Earth system models. This problem is particularly pronounced in the neotropics where bottom-up models based on water table depth are incongruent with top-down inversion models suggesting unaccounted sinks or sources of CH4. The newly documented vast areas of peatlands in the Amazon basin may account for an important unrecognized CH4 source, but the hydrologic and biogeochemical controls of CH4 dynamics from these systems remain poorly understood. We studied three zones of a peatland in Madre de Dios, Peru, to test whether CH4 emissions and pore water concentrations varied with vegetation community, soil chemistry and proximity to groundwater sources. We found that the open-canopy herbaceous zone emitted roughly one-third as much CH4 as the Mauritia flexuosa palm-dominated areas (4.7 ± 0.9 and 14.0 ± 2.4 mg CH4 m-2 h-1, respectively. Emissions decreased with distance from groundwater discharge across the three sampling sites, and tracked changes in soil carbon chemistry, especially increased soil phenolics. Based on all available data, we calculate that neotropical peatlands contribute emissions of 43 ± 11.9 Tg CH4 y-1, however this estimate is subject to geographic bias and will need revision once additional studies are published.

  11. The Role of Peat Layers on Iron Dynamics in Peatlands

    Directory of Open Access Journals (Sweden)

    Arifin Fahmi

    2010-09-01

    Full Text Available The research aimed to study the effect of peat thickness and humification stage of the peat material on Fe solubility at the peatlands with sulfidic material as substratum. The research was conducted at three conditionals of ombrogen peatlands ie ; deep, moderate and shallow peat. Soil samples were collected by using peat borer according to interlayer (the border layer of peat and mineral layer and conditional of soil horizons. The sample point depth were (cm G.s2 : 25, G.s1 : 50, Int.s : 70, M.s1 : 90 and M.s2 : 100 for shallow peat, G.m2 : 47, G.m1 : 100, Int.m : 120 and M.m1 : 135 for moderate peat and G.d3 : 50, G.d2 : 150, G.d1 : 200, Int.d : 220 and M.d1 : 235 for deep peat respectively. The results showed that most of Fe on the tested soils was found in organic forms. The peat layers above the sulfidic material decreased the Fe2+ solubility at peatlands. Fe2+ concentration in peat layer decreased with its increasing distance from sulfidic material. There was any other processes beside complexation and chelation of Fe2+ by humic material and its processes was reduction of Fe3+ and this conditions was reflected in redox potential values (Eh.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  13. Boreal Forests of Kamchatka: Structure and Composition

    Directory of Open Access Journals (Sweden)

    Markus P. Eichhorn

    2010-09-01

    Full Text Available Central Kamchatka abounds in virgin old-growth boreal forest, formed primarily by Larix cajanderi and Betula platyphylla in varying proportions. A series of eight 0.25–0.30 ha plots captured the range of forests present in this region and their structure is described. Overall trends in both uplands and lowlands are for higher sites to be dominated by L. cajanderi with an increasing component of B. platyphylla with decreasing altitude. The tree line on wet sites is commonly formed by mono-dominant B. ermanii forests. Basal area ranged from 7.8–38.1 m2/ha and average tree height from 8.3–24.7 m, both being greater in lowland forests. Size distributions varied considerably among plots, though they were consistently more even for L. cajanderi than B. platyphylla. Upland sites also contained a dense subcanopy of Pinus pumila averaging 38% of ground area. Soil characteristics differed among plots, with upland soils being of lower pH and containing more carbon. Comparisons are drawn with boreal forests elsewhere and the main current threats assessed. These forests provide a potential baseline to contrast with more disturbed regions elsewhere in the world and therefore may be used as a target for restoration efforts or to assess the effects of climate change independent of human impacts.

  14. Interannual, seasonal, and retrospective analysis of the methane and carbon dioxide budgets of a temperate peatland

    Science.gov (United States)

    D.M. Olson; T.J. Griffis; A. Noormets; R. Kolka; J. Chen

    2013-01-01

    Three years (2009-2011) of near-continuous methane (CH4) and carbon dioxide (CO2) fluxes were measured with the eddy covariance (EC) technique at a temperate peatland located within the Marcell Experimental Forest, in northern Minnesota, USA. The peatland was a net source of CH4 and a net sink of CO...

  15. Peatland vascular plant functional types affect methane dynamics by altering microbial community structure

    NARCIS (Netherlands)

    Robroek, B.J.M.; Jassey, Vincent E.J.; Kox, Martine A.R.; Berendsen, Roeland L.; Mills, Robert T.E.; Cécillon, Lauric; Puissant, Jérémy; Meima-Franke, M.; Bakker, Peter A.H.M.; Bodelier, Paul

    2015-01-01

    Peatlands are natural sources of atmospheric methane (CH4), an important greenhouse gas. It is established that peatland methane dynamics are controlled by both biotic and abiotic conditions, yet the interactive effect of these drivers is less studied, and consequently poorly understood. Climate

  16. Spatio-temporal trends of nitrogen deposition and climate effects on Sphagnum productivity in European peatlands

    International Nuclear Information System (INIS)

    Granath, Gustaf; Limpens, Juul; Posch, Maximilian; Mücher, Sander; Vries, Wim de

    2014-01-01

    To quantify potential nitrogen (N) deposition impacts on peatland carbon (C) uptake, we explored temporal and spatial trends in N deposition and climate impacts on the production of the key peat forming functional group (Sphagnum mosses) across European peatlands for the period 1900–2050. Using a modelling approach we estimated that between 1900 and 1950 N deposition impacts remained limited irrespective of geographical position. Between 1950 and 2000 N deposition depressed production between 0 and 25% relative to 1900, particularly in temperate regions. Future scenarios indicate this trend will continue and become more pronounced with climate warming. At the European scale, the consequences for Sphagnum net C-uptake remained small relative to 1900 due to the low peatland cover in high-N areas. The predicted impacts of likely changes in N deposition on Sphagnum productivity appeared to be less than those of climate. Nevertheless, current critical loads for peatlands are likely to hold under a future climate. - Highlights: • We model the effect of N deposition combined with climate on production of Sphagnum between 1900 and 2050. • Spatially explicit projections are indicated on an updated European peatland distribution map. • Results stress the vulnerability of temperate Sphagnum peatlands to current and future N deposition. • Future impacts of N deposition on Sphagnum productivity likely depend more on climate change than on N deposition rate. - Temperate Sphagnum peatlands are vulnerable to current and future N deposition and current critical loads for peatlands are likely to hold under a future climate

  17. Evaluating the use of testate amoebae for palaeohydrological reconstruction in permafrost peatlands

    DEFF Research Database (Denmark)

    Swindles, Graeme T.; Amesbury, Matthew J.; Turner, T. Edward

    2015-01-01

    The melting of high-latitude permafrost peatlands is a major concern due to a potential positive feedback on global climate change. We examine the ecology of testate amoebae in permafrost peatlands, based on sites in Sweden (similar to 200 km north of the Arctic Circle). Multivariate statistical ...

  18. Influence of climate change factors on carbon dynamics in northern forested peatlands

    Science.gov (United States)

    C.C Trettin; R. Laiho; K. Minkkinen; J. Laine

    2005-01-01

    Peatlands are carbon-accumulating wetland ecosystems, developed through an imbalance among organic matter production and decomposition processes. Soil saturation is the principal cause of anoxic conditions that constrain organic matter decay. Accordingly, changes in the hydrologic regime will affect the carbon (C) dynamics in forested peatlands. Our objective is to...

  19. Community based ecological restoration of peatland in Central Mongolia for climate change mitigation and adaptation

    NARCIS (Netherlands)

    Minayeva, Tatiana; Chultem, Dugarjav; Grootjans, Ab; Yamkhin, Jambaljav; Sirin, Andrey; Suvorov, Gennady; Batdorj, Oyunbileg; Tsamba, Batdorj

    2017-01-01

    Peatlands cover almost 2 % of Mongolia. They play crucial role in regulation of key natural processes in ecosystems and provide unique resources to maintain traditional way of life and livelihoods of herders. During the last decades, Mongolian peatlands severely degraded both due to the climate

  20. Seasonal changes in peatland surface elevation recorded at GPS stations in the Red Lake Peatlands, northern Minnesota, USA

    Science.gov (United States)

    Reeve, A.S.; Glaser, P.H.; Rosenberry, Donald O.

    2013-01-01

    Northern peatlands appear to hold large volumes of free-phase gas (e.g., CH4 and CO2), which has been detected by surface deformations, pore pressure profiles, and electromagnetic surveys. Determining the gas content and its impact in peat is challenging because gas storage depends on both the elastic properties of the peat matrix and the buoyant forces exerted by pore fluids. We therefore used a viscoelastic deformation model to estimate these variables by adjusting model runs to reproduce observed changes in peat surface elevation within a 1300 km2 peatland. A local GPS network documented significant changes in surface elevations throughout the year with the greatest vertical displacements associated with rapid changes in peat water content and unloadings due to melting of the winter snowpack. These changes were coherent with changes in water table elevation and also abnormal pore pressure changes measured by nests of instrumented piezometers. The deformation model reproduced these changes when the gas content was adjusted to 10% of peat volume, and Young's modulus was varied between 5 and 100 kPa as the peat profile shifted from tension to compression. In contrast, the model predicted little peat deformation when the gas content was 3% or lower. These model simulations are consistent with previous estimates of gas volume in northern peatlands and suggest an upper limit of gas storage controlled by the elastic moduli of the peat fabric.

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

    Science.gov (United States)

    Minayeva, Tatiana; Sirin, Andrey; Dugarjav, Chultem

    2016-04-01

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

  2. Long-term carbon accumulation in Andes peatlands

    Science.gov (United States)

    Huaman, Yizet; Moreira-turq, Patricia; Willems, Bram; Espinoza, Raul; Turq, Bruno; Apaéstegui, James; Llanos, Romina

    2017-04-01

    High-altitude peatlands of the Andes still remain relatively unexplored since most of the studies on carbon capture in tropical soils have focused on peatlands in low altitude areas, leaving aside the importance of the study of high mountain wetlands, currently called "bofedales" located between 3000 and 5000 masl, covering most of the Andes mountains in South America. These peatlands in turn may also represent important paleoclimatic records. In this study, we investigated three peatland cores (APA-01, APA2-01, and APA2-02) at different altitudes (4210 m, 4420 m and 4432 m, respectively) in high Andean Peatlands of southern Peru. The peatland studied is located at the headwater basin Cachi River, in the town of Ayacucho, Peru. The aim of this study was to evaluate the role played by past climatic changes on the peatlands carbon accumulation. Each core was sectioned centimeter by centimeter and sub samples (n = 31) were collected for radiocarbon dating by AMS (acceleration mass spectrometer) and were used to create a sedimentological model based on the program Clam2.2R. The concentrations of carbon and nitrogen were determined from a C / H / N elemental analyzer and the stable carbon and nitrogen isotopes (δ13C and δ15N) were also analyzed. The bulk density was determined based on the volume occupied by the sediment (g /cm3). Finally, the carbon accumulation rate (gC m-2año-1) was determined. The three cores were characterized by two sedimentary units, the results present in the first sedimentary unit of APA01 an average long-term carbon accumulation rate of 59 gC m-2año-1, APA2-01 with 32 gC m-2año-1 and finally APA2-02 with 24 gC m-2año-1; for the second sedimentary unit we have: APA01 on average 17 gC m-2año-1, APA2-01 with 33 gC m-2año-1 and finally APA2-02 with 49 gC m-2año-1. In conclusion, we can say that the carbon accumulation rate for the first sedimentary unit of the three cores decreases as the altitude increases; on the other hand, we have the

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

    Science.gov (United States)

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

    2015-01-27

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

  4. Thermophysical tests of buffer materials

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, H. [ITC, Tokyo (Japan); Taniguchi, Wataru

    1999-03-01

    Thermodynamic properties of buffer materials were measured for putting in order thermodynamic constants to be used in the near-field thermal analysis. The thermal diffusivity and thermal conductivity were measured as functions of the water content and temperature to deduce the specific heat. The thermal conductivity and specific heat varied significantly as the water content changed. Obtained values of the specific heat agreed well the expected values calculated based on the constituents of the buffer material. Temperature dependence of the thermodynamic constants was found small below 90degC. From the findings, the thermal conductivity and specific heat of the buffer material were formulated as functions of the water content. Thermodynamic study of powdery bentonite was carried out as well with a purpose of use for filling apertures in the artificial barrier. (H. Baba)

  5. ACETIC ACID AND A BUFFER

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  6. Groundwater-surface water interactions across scales in a boreal landscape investigated using a numerical modelling approach

    Science.gov (United States)

    Jutebring Sterte, Elin; Johansson, Emma; Sjöberg, Ylva; Huseby Karlsen, Reinert; Laudon, Hjalmar

    2018-05-01

    Groundwater and surface-water interactions are regulated by catchment characteristics and complex inter- and intra-annual variations in climatic conditions that are not yet fully understood. Our objective was to investigate the influence of catchment characteristics and freeze-thaw processes on surface and groundwater interactions in a boreal landscape, the Krycklan catchment in Sweden. We used a numerical modelling approach and sub-catchment evaluation method to identify and evaluate fundamental catchment characteristics and processes. The model reproduced observed stream discharge patterns of the 14 sub-catchments and the dynamics of the 15 groundwater wells with an average accumulated discharge error of 1% (15% standard deviation) and an average groundwater-level mean error of 0.1 m (0.23 m standard deviation). We show how peatland characteristics dampen the effect of intense rain, and how soil freeze-thaw processes regulate surface and groundwater partitioning during snowmelt. With these results, we demonstrate the importance of defining, understanding and quantifying the role of landscape heterogeneity and sub-catchment characteristics for accurately representing catchment hydrological functioning.

  7. BOREAS TE-04 Gas Exchange Data from Boreal Tree Species

    Data.gov (United States)

    National Aeronautics and Space Administration — Contains TE-04 data on gas exchange studies of photosynthesis, respiration and stomatal conductance of boreal forest species using the MPH-1000 system.

  8. BOREAS TE-04 Branch Bag Data from Boreal Tree Species

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Contains 1996 TE-04 data of branch bag studies of photosynthesis, respiration and stomatal conductance of boreal forest species using the open MPH-1000...

  9. NPP Boreal Forest: Kuusamo, Finland, 1967-1971, R1

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains three files (.txt format). One file provides stand characteristics, biomass, and production allocation data for an old-growth boreal...

  10. NPP Boreal Forest: Kuusamo, Finland, 1967-1972, R1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains three files (.txt format). One file provides stand characteristics, biomass, and production allocation data for an old-growth boreal forest...

  11. NPP Boreal Forest: Schefferville, Canada, 1974, R1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains two files (.txt format). One file provides above- and below-ground biomass, soil, and nutrient data for a mature boreal ecosystem (subarctic...

  12. NPP Boreal Forest: Schefferville, Canada, 1974, R1

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains two files (.txt format). One file provides above- and below-ground biomass, soil, and nutrient data for a mature boreal ecosystem...

  13. A Capital Adequacy Buffer Model

    NARCIS (Netherlands)

    D.E. Allen (David); M.J. McAleer (Michael); R.J. Powell (Robert); A.K. Singh (Abhay)

    2013-01-01

    markdownabstract__Abstract__ In this paper, we develop a new capital adequacy buffer model (CABM) which is sensitive to dynamic economic circumstances. The model, which measures additional bank capital required to compensate for fluctuating credit risk, is a novel combination of the Merton

  14. Smoothing type buffer memory device

    International Nuclear Information System (INIS)

    Podorozhnyj, D.M.; Yashin, I.V.

    1990-01-01

    The layout of the micropower 4-bit smoothing type buffer memory device allowing one to record without counting the sequence of input randomly distributed pulses in multi-channel devices with serial poll, is given. The power spent by a memory cell for one binary digit recording is not greater than 0.15 mW, the device dead time is 10 mus

  15. Responsible management of tropical peatlands: balancing competing demands on a fragile resource

    Science.gov (United States)

    Page, Susan; Evans, Christopher; Gauci, Vincent

    2017-04-01

    In 2010 the International Peatland Society published a strategy for responsible peatland management, with the following guiding principles: (i) ensure that high conservation value peatlands are identified and conserved, (ii) manage 'utilised' peatlands responsibly, and (iii) rehabilitate or restore drained, degraded or otherwise irreversibly changed peatlands to restore as many ecological and landscape functions as possible. At the time of its publication, the main focus of the strategy was on northern peatlands, although a few partner organisations in SE Asia were involved in the strategy consultation process. Given the rapid rate of peatland development in SE Asia in the last 7 years and the growing interest in tropical peatland rehabilitation and restoration, we believe that it is now timely to review what a strategy for responsible tropical peatland management might look like. SE Asia's peatlands cover 250,000 km2 of the region and store 69 Gt C but they are subject to continuing deforestation, biodiversity loss, land subsidence/flooding, increasing greenhouse gas (GHG) emissions, and health impacts due to air pollution from land-clearing fires, all of which pose huge regional and global challenges. Around 75% of the peatlands have been deforested in the last 20 years, with 35% of cleared land now under industrial plantation, 34% under smallholder cultivation, and 25% unutilised, largely as a result of uncontrolled land-clearing fires. The production intensity (GHG emissions per calorie produced) of crops grown on SE Asian organic soils is among the highest in the world (Carlson et al. 2016). There are clear tensions between reconciling peatland management for conservation goals (of biodiversity, carbon and natural resources) with economic and livelihood development goals. A balance needs to be struck between the absolute value and distribution of short term economic gains vs. peatland management strategies that deliver longer-term, sustainable and shared

  16. Boreal forest biomass classification with TanDEM-X

    OpenAIRE

    Torano Caicoya, Astor; Kugler, Florian; Papathanassiou, Kostas; Hajnsek, Irena

    2013-01-01

    High spatial resolution X-band interferometric SAR data from the TanDEM-X, in the operational DEM generation mode, are sensitive to forest structure and can therefore be used for thematic boreal forest classification of forest environments. The interferometric coherence in absence of temporal decorrelation depends strongly on forest height and structure. Due to the rather homogenous structure of boreal forest, forest biomass can be derived from forest height, on the basis of allometric equati...

  17. Maximizing peatland forest regeneration success at lowest cost to the atmosphere. Effects of soil preparation on Scots pine seedling vitality and GHG emissions

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, M.

    2013-06-01

    appears unwarranted at least on nutrient-poor, boreal forestry-drained peatland sites. The overall climatic impact of soil preparation, in the forms of mounding and scalping, three years after application expressed in terms of CO{sub 2} equivalents (100-year GWP), was neutral compared to leaving soil unprepared. The core findings of this research support mounding as the best alternative on nutrient-poor, drained peatland sites when the goal is to maximize the regeneration success of Scots pine after clearcutting with minimal impact on soil GHG emissions. In the future, development of soil preparation methodology is particularly deserving of further attention. While it may not be the sexiest research topic in the worldwide rat race of the modern day, it is nonetheless of substantial importance in a country highly specialized not only in the utilization but also the rejuvenation of wood resources on drained peatlands. (orig.)

  18. Symbiosis revisited: phosphorus and acid buffering stimulate N2 fixation but not Sphagnum growth

    Science.gov (United States)

    van den Elzen, Eva; Kox, Martine A. R.; Harpenslager, Sarah F.; Hensgens, Geert; Fritz, Christian; Jetten, Mike S. M.; Ettwig, Katharina F.; Lamers, Leon P. M.

    2017-03-01

    In pristine Sphagnum-dominated peatlands, (di)nitrogen (N2) fixing (diazotrophic) microbial communities associated with Sphagnum mosses contribute substantially to the total nitrogen input, increasing carbon sequestration. The rates of symbiotic nitrogen fixation reported for Sphagnum peatlands, are, however, highly variable, and experimental work on regulating factors that can mechanistically explain this variation is largely lacking. For two common fen species (Sphagnum palustre and S. squarrosum) from a high nitrogen deposition area (25 kg N ha-1 yr-1), we found that diazotrophic activity (as measured by 15 - 15N2 labeling) was still present at a rate of 40 nmol N gDW-1 h-1. This was surprising, given that nitrogen fixation is a costly process. We tested the effects of phosphorus availability and buffering capacity by bicarbonate-rich water, mimicking a field situation in fens with stronger groundwater or surface water influence, as potential regulators of nitrogen fixation rates and Sphagnum performance. We expected that the addition of phosphorus, being a limiting nutrient, would stimulate both diazotrophic activity and Sphagnum growth. We indeed found that nitrogen fixation rates were doubled. Plant performance, in contrast, did not increase. Raised bicarbonate levels also enhanced nitrogen fixation, but had a strong negative impact on Sphagnum performance. These results explain the higher nitrogen fixation rates reported for minerotrophic and more nutrient-rich peatlands. In addition, nitrogen fixation was found to strongly depend on light, with rates 10 times higher in light conditions suggesting high reliance on phototrophic organisms for carbon. The contrasting effects of phosphorus and bicarbonate on Sphagnum spp. and their diazotrophic communities reveal strong differences in the optimal niche for both partners with respect to conditions and resources. This suggests a trade-off for the symbiosis of nitrogen fixing microorganisms with their Sphagnum

  19. Environmental control of methane fluxes over a Danish peatland

    Science.gov (United States)

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

    2009-12-01

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

  20. Potential for using remote sensing to estimate carbon fluxes across northern peatlands - A review.

    Science.gov (United States)

    Lees, K J; Quaife, T; Artz, R R E; Khomik, M; Clark, J M

    2018-02-15

    Peatlands store large amounts of terrestrial carbon and any changes to their carbon balance could cause large changes in the greenhouse gas (GHG) balance of the Earth's atmosphere. There is still much uncertainty about how the GHG dynamics of peatlands are affected by climate and land use change. Current field-based methods of estimating annual carbon exchange between peatlands and the atmosphere include flux chambers and eddy covariance towers. However, remote sensing has several advantages over these traditional approaches in terms of cost, spatial coverage and accessibility to remote locations. In this paper, we outline the basic principles of using remote sensing to estimate ecosystem carbon fluxes and explain the range of satellite data available for such estimations, considering the indices and models developed to make use of the data. Past studies, which have used remote sensing data in comparison with ground-based calculations of carbon fluxes over Northern peatland landscapes, are discussed, as well as the challenges of working with remote sensing on peatlands. Finally, we suggest areas in need of future work on this topic. We conclude that the application of remote sensing to models of carbon fluxes is a viable research method over Northern peatlands but further work is needed to develop more comprehensive carbon cycle models and to improve the long-term reliability of models, particularly on peatland sites undergoing restoration. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    Peatlands in Amazonian Peru are known to store large quantities of carbon, but there is high uncertainty in the spatial extent and total carbon stocks of these ecosystems. Here, we use a multi-sensor (Landsat, ALOS PALSAR and SRTM) remote sensing approach, together with field data including 24 forest census plots and 218 peat thickness measurements, to map the distribution of peatland vegetation types and calculate the combined above- and below-ground carbon stock of peatland ecosystems in the Pastaza-Marañon foreland basin in Peru. We find that peatlands cover 35 600 ± 2133 km 2 and contain 3.14 (0.44–8.15) Pg C. Variation in peat thickness and bulk density are the most important sources of uncertainty in these values. One particular ecosystem type, peatland pole forest, is found to be the most carbon-dense ecosystem yet identified in Amazonia (1391 ± 710 Mg C ha −1 ). The novel approach of combining optical and radar remote sensing with above- and below-ground carbon inventories is recommended for developing regional carbon estimates for tropical peatlands globally. Finally, we suggest that Amazonian peatlands should be a priority for research and conservation before the developing regional infrastructure causes an acceleration in the exploitation and degradation of these ecosystems. (letter)

  2. How temporal patterns in rainfall determine the geomorphology and carbon fluxes of tropical peatlands

    Science.gov (United States)

    Hoyt, Alison M.; Gandois, Laure; Eri, Jangarun; Dommain, René; Abu Salim, Kamariah; Kai, Fuu Ming; Haji Su’ut, Nur Salihah; Harvey, Charles F.

    2017-01-01

    Tropical peatlands now emit hundreds of megatons of carbon dioxide per year because of human disruption of the feedbacks that link peat accumulation and groundwater hydrology. However, no quantitative theory has existed for how patterns of carbon storage and release accompanying growth and subsidence of tropical peatlands are affected by climate and disturbance. Using comprehensive data from a pristine peatland in Brunei Darussalam, we show how rainfall and groundwater flow determine a shape parameter (the Laplacian of the peat surface elevation) that specifies, under a given rainfall regime, the ultimate, stable morphology, and hence carbon storage, of a tropical peatland within a network of rivers or canals. We find that peatlands reach their ultimate shape first at the edges of peat domes where they are bounded by rivers, so that the rate of carbon uptake accompanying their growth is proportional to the area of the still-growing dome interior. We use this model to study how tropical peatland carbon storage and fluxes are controlled by changes in climate, sea level, and drainage networks. We find that fluctuations in net precipitation on timescales from hours to years can reduce long-term peat accumulation. Our mathematical and numerical models can be used to predict long-term effects of changes in temporal rainfall patterns and drainage networks on tropical peatland geomorphology and carbon storage. PMID:28607068

  3. How temporal patterns in rainfall determine the geomorphology and carbon fluxes of tropical peatlands.

    Science.gov (United States)

    Cobb, Alexander R; Hoyt, Alison M; Gandois, Laure; Eri, Jangarun; Dommain, René; Abu Salim, Kamariah; Kai, Fuu Ming; Haji Su'ut, Nur Salihah; Harvey, Charles F

    2017-06-27

    Tropical peatlands now emit hundreds of megatons of carbon dioxide per year because of human disruption of the feedbacks that link peat accumulation and groundwater hydrology. However, no quantitative theory has existed for how patterns of carbon storage and release accompanying growth and subsidence of tropical peatlands are affected by climate and disturbance. Using comprehensive data from a pristine peatland in Brunei Darussalam, we show how rainfall and groundwater flow determine a shape parameter (the Laplacian of the peat surface elevation) that specifies, under a given rainfall regime, the ultimate, stable morphology, and hence carbon storage, of a tropical peatland within a network of rivers or canals. We find that peatlands reach their ultimate shape first at the edges of peat domes where they are bounded by rivers, so that the rate of carbon uptake accompanying their growth is proportional to the area of the still-growing dome interior. We use this model to study how tropical peatland carbon storage and fluxes are controlled by changes in climate, sea level, and drainage networks. We find that fluctuations in net precipitation on timescales from hours to years can reduce long-term peat accumulation. Our mathematical and numerical models can be used to predict long-term effects of changes in temporal rainfall patterns and drainage networks on tropical peatland geomorphology and carbon storage.

  4. Development in techniques for studying forest roads on peatlands

    International Nuclear Information System (INIS)

    Saarilahti, M.

    1988-01-01

    A light seismic method, a short-pulse radar and a microwave probe are tested in assessing the properties of a forest road constructed on peatland. The light seismic method gave reliable values for estimating the bearing capacity of the road. It was found that bearing capacity was mostly dependent on embankment thickness, but quality of labric might also have an influence. Embankment thickness and peat depth can be measured on the radargram, and some additional information on road bed and peat obtained. The microwave peat probe permits recording of the continuous moisture profile in situ, which improves accuracy of planning

  5. Use of ash in the fertilisation of peatland forests

    International Nuclear Information System (INIS)

    Moilanen, M.; Korpilahti, A.

    2000-01-01

    About 100,000 tonnes of bark and other wood-based ash are produced annually by the forest industries and heating plants in Finland. This amount would be sufficient for fertilising about 25,000 hectares of forest. When applied to peatland forests, this would produce extra forest growth of about 75,000 m 3 per a year. When considering the objectives of forestry, the practical benefits and economic profitability of ash fertilisation are at their peak on peatlands rich in nitrogen. Wood ash induces added tree growth (measured in terms of stemwood) in pine stands on herb- and sedge-rich parklands within 2-3 years of application. On nitrogen-deficient dwarf-shrub and Sphagnum-rich peatlands this growth reaction manifests itself only after 7-8 years have passed and even then at a considerably lower level. The application of mere ash does not result in notable increases in tree growth on upland forest sites. However, ash does change the growth conditions by reducing the acidity of the soil and by accelerating microbial decomposition. The phosphorus contained in ash has not been observed to have been leached into drainage waters on drained sites, at least not during the first two years after application, provided that care has been practised when spreading ash. However, the movement of readily-soluble nutrients has been observed and more so on nutrient-poor sites than on nutrient-rich sites. Although the suitability of ash as fertiliser in peatland forests has been recognised on the basis of long-term ash trials established at the Finnish Forest Research Institute, ash fertilisation has not been carried out made on a practical scale mainly because of the dust problem when spreading it. The purpose of pretreatment with ash is first and foremost to transform the ash into sufficiently dust-free form to enable it to be spread readily. An added advantage is that pelletised ash causes a lesser pH shock to plank than ash in dust form. (orig.)

  6. Development in techniques for studying forest roads on peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Saarilahti, M.

    1988-07-01

    A light seismic method, a short-pulse radar and a microwave probe are tested in assessing the properties of a forest road constructed on peatland. The light seismic method gave reliable values for estimating the bearing capacity of the road. It was found that bearing capacity was mostly dependent on embankment thickness, but quality of labric might also have an influence. Embankment thickness and peat depth can be measured on the radargram, and some additional information on road bed and peat obtained. The microwave peat probe permits recording of the continuous moisture profile in situ, which improves accuracy of planning.

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

    Science.gov (United States)

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

    2016-04-01

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

  8. The thermodynamic-buffer enzymes.

    Science.gov (United States)

    Stucki, J W

    1980-08-01

    Oxidative phosphorylation operates at optimal efficiency if and only if the condition of conductance matching L33/L11 = square root 1-q2 is fulfilled. In this relation L11 is the phenomenological conductance of phosphorylation, L33 the phenomenological conductance of the load, i.e. the irreversible ATP-utilizing processes in the cell, and q the degree of coupling of oxidative phosphorylation driven by respiration. Since during short time intervals L11 and q are constant whereas L33 fluctuates in the cell, oxidative phosphorylation would only rarely operate at optimal efficiency due to violation of conductance matching. This paper demonstrates that the reversible ATP-utilizing reaction catalyzed by adenylate kinase can effectively compensate deviations from conductance matching in the presence of a fluctuating L33 and hence allows oxidative phosphorylation to operate at optimal efficiency in the cell. Since the adenylate kinase reaction was found to buffer a thermodynamic potential, i.e. the phosphate potential, this finding was generalized to the concept of thermodynamic buffering. The thermodynamic buffering ability of the adenylate kinase reaction was demonstrated by experiments with incubated rat-liver mitochondria. Considerations of changes introduced in the entropy production by the adenylate kinase reaction allowed to establish the theoretical framework for thermodynamic buffering. The ability of thermodynamic buffering to compensate deviations from conductance matching in the presence of fluctuating loads was demonstrated by computer simulations. The possibility of other reversible ATP-utilizing reactions, like the ones catalyzed by creatine kinase and arginine kinase, to contribute to thermodynamic buffering is discussed. Finally, the comparison of the theoretically calculated steady-stae cytosolic adenine nucleotide concentrations with experimental data from perfused livers demonstrated that in livers from fed rats conductance matching is fulfilled on a

  9. Long-term effects of ozone on CO2 exchange in peatland microcosms

    DEFF Research Database (Denmark)

    Haapala, JK; Mörsky, SK; Rinnan, Riikka

    2011-01-01

    Effects of elevated tropospheric ozone concentration on the CO2 exchange of peatland microcosms and the photosynthetic capacity of the dominating sedge, Eriophorum vaginatum, were studied in a four-year open-field experiment. The net ecosystem CO2 exchange and the dark respiration rate of the mic......Effects of elevated tropospheric ozone concentration on the CO2 exchange of peatland microcosms and the photosynthetic capacity of the dominating sedge, Eriophorum vaginatum, were studied in a four-year open-field experiment. The net ecosystem CO2 exchange and the dark respiration rate...... exchange of the peatland microcosms....

  10. Urban Runoff: Model Ordinances for Aquatic Buffers

    Science.gov (United States)

    Aquatic Buffers serve as natural boundaries between local waterways and existing development. The model and example ordinaces below provide suggested language or technical guidance designed to create the most effective stream buffer zones possible.

  11. Buffer Zone Requirements for Soil Fumigant Applications

    Science.gov (United States)

    Updated pesticide product labels require fumigant users to establish a buffer zone around treated fields to reduce risks to bystanders. Useful information includes tarp testing guidance and a buffer zone calculator.

  12. Swelling characteristics of buffer material

    International Nuclear Information System (INIS)

    Suzuki, Hideaki; Fujita, Tomoo

    1999-12-01

    After emplacement of the engineered barrier system (EBS), it is expected that the near-field environment will be impacted by phenomena such as heat dissipation by conduction and other heat transfer mechanism, infiltration of groundwater from the surrounding rock into the EBS, generation of swelling pressure in the buffer due to water infiltration and the stress imposed by the overburden pressure. These phenomena are not all independent, but can be strongly influenced by, and coupled with, each other. Evaluating these coupled thermo-hydro-mechanical phenomena is important in order to clarify the initial transient behavior of the engineered barrier system within the near-field. This report describes the results on measurement of swelling amount and stress at boundary built up under restraint condition with water uptake. The following results are identified. (1) The swelling stress of buffer material at saturated condition tends to be independent of effects of pore water pressure and synthetic sea water, and to decrease with increasing temperature. The swelling stress can be explained by the effective dry density. (2) The strain due to swelling estimated from the results of the swelling amount of buffer material is proportional to swelling stress. (3) The swelling stress and strain under unsaturated condition increase with water uptake. (author)

  13. Fractionation of 137Cs and Pu in natural peatland

    International Nuclear Information System (INIS)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2014-08-01

    High Cs-137 concentrations in plants growing on peatland inspired us to investigate the quantity of its bioavailable fraction in natural peat. Our investigation aims to: a) estimate the quantity of bioavailable Cs-137 and Pu present in peat, b) verify the similarity of Cs-137 and K-40 behaviours, and c) perform a quantification of Cs-137 and Pu transfer from peat to plants. We analysed the vertical distribution of Cs-137 and Pu isotopes in the peat and their concentrations in plants growing on these places. Bioavailability of radionuclides was investigated by sequential extraction. Sequential analyses revealed that it was the upper layer which contained the majority of Cs-137 in an available form while deeper layers retained Cs-137 in immobile fractions. We can conclude that 18% of all Cs-137 in the peat is still bioavailable. Despite of the low quantity of bioavailable fraction of Cs-137 its transfer factor reached extremely high values. In the case of Pu, 64% of its total amount was associated with fulvic/humic acids which resulted in the high transfer factor from peat to plants. 27 years after the Chernobyl nuclear accident, the significant part of radionuclides deposited in peatland is still bioavailable. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Palaeoecology of testate amoebae in a tropical peatland.

    Science.gov (United States)

    Swindles, Graeme T; Lamentowicz, Mariusz; Reczuga, Monika; Galloway, Jennifer M

    2016-09-01

    We present the first detailed analysis of subfossil testate amoebae from a tropical peatland. Testate amoebae were analysed in a 4-m peat core from western Amazonia (Peru) and a transfer function developed from the site was applied to reconstruct changes in water table over the past ca. 8,000 years. Testate amoebae were in very low abundance in the core, especially in the lower 125cm, due to a combination of poor preservation and obscuration by other organic matter. A modified preparation method enabled at least 50 testate amoebae to be counted in each core sample. The most abundant taxa preserved include Centropyxis aculeata, Hyalosphenia subflava, Phryganella acropodia and Trigonopyxis arcula. Centropyxis aculeata, an unambiguous wet indicator, is variably present and indicates several phases of near-surface water table. Our work shows that even degraded, low-abundance assemblages of testate amoebae can provide useful information regarding the long-term ecohydrological developmental history of tropical peatlands. Copyright © 2015 Elsevier GmbH. All rights reserved.

  16. Opportunities for reducing greenhouse gas emissions in tropical peatlands.

    Science.gov (United States)

    Murdiyarso, D; Hergoualc'h, K; Verchot, L V

    2010-11-16

    The upcoming global mechanism for reducing emissions from deforestation and forest degradation in developing countries should include and prioritize tropical peatlands. Forested tropical peatlands in Southeast Asia are rapidly being converted into production systems by introducing perennial crops for lucrative agribusiness, such as oil-palm and pulpwood plantations, causing large greenhouse gas (GHG) emissions. The Intergovernmental Panel on Climate Change Guidelines for GHG Inventory on Agriculture, Forestry, and Other Land Uses provide an adequate framework for emissions inventories in these ecosystems; however, specific emission factors are needed for more accurate and cost-effective monitoring. The emissions are governed by complex biophysical processes, such as peat decomposition and compaction, nutrient availability, soil water content, and water table level, all of which are affected by management practices. We estimate that total carbon loss from converting peat swamp forests into oil palm is 59.4 ± 10.2 Mg of CO(2) per hectare per year during the first 25 y after land-use cover change, of which 61.6% arise from the peat. Of the total amount (1,486 ± 183 Mg of CO(2) per hectare over 25 y), 25% are released immediately from land-clearing fire. In order to maintain high palm-oil production, nitrogen inputs through fertilizer are needed and the magnitude of the resulting increased N(2)O emissions compared to CO(2) losses remains unclear.

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

    Science.gov (United States)

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

    2013-01-01

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

  18. Symbiosis revisited : Phosphorus and acid buffering stimulate N2 fixation but not Sphagnum growth

    NARCIS (Netherlands)

    Van Den Elzen, Eva; Kox, Martine A R; Harpenslager, Sarah F.; Hensgens, Geert; Fritz, Christian; Jetten, Mike S M; Ettwig, Katharina F.; Lamers, Leon P M

    2017-01-01

    In pristine Sphagnum-dominated peatlands, (di)nitrogen (N2) fixing (diazotrophic) microbial communities associated with Sphagnum mosses contribute substantially to the total nitrogen input, increasing carbon sequestration. The rates of symbiotic nitrogen fixation reported for Sphagnum peatlands,

  19. Buffer erosion in dilute groundwater

    International Nuclear Information System (INIS)

    Schatz, T.; Kanerva, N.; Martikainen, J.; Sane, P.; Olin, M.; Seppaelae, A.; Koskinen, K.

    2013-08-01

    One scenario of interest for repository safety assessment involves the loss of bentonite buffer material in contact with dilute groundwater flowing through a transmissive fracture interface. In order to examine the extrusion/erosion behavior of bentonite buffer material under such circumstances, a series of experiments were performed in a flow-through, 1 mm aperture, artificial fracture system. These experiments covered a range of solution chemistry (salt concentration and composition), material composition (sodium montmorillonite and admixtures with calcium montmorillonite), and flow velocity conditions. No erosion was observed for sodium montmorillonite against solution compositions from 0.5 g/L to 10 g/L NaCl. No erosion was observed for 50/50 calcium/sodium montmorillonite against 0.5 g/L NaCl. Erosion was observed for both sodium montmorillonite and 50/50 calcium/sodium montmorillonite against solution compositions ≤ 0.25 g/L NaCl. The calculated erosion rates for the tests with the highest levels of measured erosion, i.e., the tests run under the most dilute conditions (ionic strength (IS) < ∼1 mM), were well-correlated to flow velocity, whereas the calculated erosion rates for the tests with lower levels of measured erosion, i.e., the tests run under somewhat less dilute conditions (∼1 mM < IS < ∼4 mM), were not similarly correlated indicating that material and solution composition can significantly affect erosion rates. In every experiment, both erosive and non-erosive, emplaced buffer material extruded into the fracture and was observed to be impermeable to water flowing in the fracture effectively forming an extended diffusive barrier around the intersecting fracture/buffer interface. Additionally, a model which was developed previously to predict the rate of erosion of bentonite buffer material in low ionic strength water in rock fracture environments was applied to three different cases: sodium montmorillonite expansion in a vertical tube, a

  20. BUFFER CAPACITY IN HETEROGENEOUS MULTICOMPONENT SYSTEMS. REVIEW

    Directory of Open Access Journals (Sweden)

    Oxana Spinu

    2015-12-01

    Full Text Available The quantitative basis of the theory of buffer properties for two-phase acid-base buffer systems and for multicomponent heterogeneous systems has been derived. The analytical equations with respect to all components for diverse multicomponent systems were deduced. It has been established, that the buffer capacities of components are mutually proportional.

  1. Doped LZO buffer layers for laminated conductors

    Science.gov (United States)

    Paranthaman, Mariappan Parans [Knoxville, TN; Schoop, Urs [Westborough, MA; Goyal, Amit [Knoxville, TN; Thieme, Cornelis Leo Hans [Westborough, MA; Verebelyi, Darren T [Oxford, MA; Rupich, Martin W [Framingham, MA

    2010-03-23

    A laminated conductor includes a metallic substrate having a surface, a biaxially textured buffer layer supported by the surface of the substrate, the biaxially textured buffer layer comprising LZO and a dopant for mitigating metal diffusion through the LZO, and a biaxially textured conductor layer supported by the biaxially textured buffer layer.

  2. RESEARCH NEEDS IN RIPARIAN BUFFER RESTORATION

    Science.gov (United States)

    Riparian buffer restorations are used as management tools to produce favorable water quality impacts; moreover, the basis for riparian buffers as an instrument of water quality restoration rests on a relatively firm foundation. However, the extent to which buffers can restore rip...

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

    Science.gov (United States)

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

    2013-04-01

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

  4. Abrupt vegetation transitions characterise long-term Amazonian peatland development

    Science.gov (United States)

    Roucoux, K. H.; Baker, T. R.; Gosling, W. D.; Honorio Coronado, E.; Jones, T. D.; Lahteenoja, O.; Lawson, I. T.

    2012-04-01

    Recent investigations of wetlands in western Amazonia have revealed the presence of extensive peatlands with peat deposits of up to 8 m-thick developing under a variety of vegetation types (Lähteenoja et al. 2012). Estimated to cover 150,000 km2 (Schulman et al. 1999), these peatlands make a valuable contribution to landscape and biological diversity and represent globally important carbon stores. In order to understand the processes leading to peat formation, and the sensitivity of these environments to future climatic change, it is necessary to understand their long-term history. The extent to which peatland vegetation changes over time, the stability of particular communities, the controls on transitions between vegetation types and how these factors relate to the accumulation of organic matter are not yet known. We report the first attempt to establish the long-term (millennial scale) vegetation history of a recently-described peatland site: Quistococha, a palm swamp, or aguajal, close to Iquitos in northern Peru. The vegetation is dominated by Mauritia flexuosa and Mauritiella armata and occupies a basin which is thought to be an abandoned channel of the River Amazon. We obtained a 4 m-long peat sequence from the deepest part of the basin. AMS-radiocarbon dating yielded a maximum age of 2,212 cal yr BP for the base of the peat, giving an average accumulation rate of 18 cm per century. Below the peat are 2 m of uniform, largely inorganic pale grey clays of lacustrine origin, which are underlain by an unknown thickness of inorganic sandy-silty clay of fluvial origin. Pollen analysis, carried out at c. 88-year intervals, shows the last 2,212 years to be characterised by the development of at least four distinct vegetation communities, with peat accumulating throughout. The main phases were: (1) Formation of Cyperaceae (sedge) fen coincident with peat initiation; (2) A short-lived phase of local Mauritia/Mauritiella development; (3) Development of mixed wet

  5. Carbon in boreal coniferous forest soil

    Energy Technology Data Exchange (ETDEWEB)

    Westman, C.J.; Ilvesniemi, H.; Liski, J.; Mecke, M. [Helsinki Univ. (Finland). Dept. of Forest Ecology; Fritze, H.; Helmisaari, H.S.; Pietikaeinen, J.; Smolander, A. [Finnish Forest Research Inst., Vantaa (Finland)

    1996-12-31

    The working hypothesis of the research was that the soil of boreal forests is a large carbon store and the amount of C is still increasing in young soils, like in the forest soils of Finland, which makes these soils important sinks for atmospheric CO{sub 2}. Since the processes defining the soil C balance, primary production of plants and decomposition, are dependent on environmental factors and site properties, it was assumed that the organic carbon pool in the soil is also dependent on the same factors. The soil C store is therefore likely to change in response to climatic warming. The aim of this research was to estimate the C balance of forest soil in Finland and predict changes in the balance in response to changes in climatic conditions. To achieve the aim (1) intensive empirical experimentation on the density of C in different pools in the soil and on fluxes between the pools was done was done, (2) the effect of site fertility and climate on the amount and properties of organic C in forest soil was investigated and (3) dynamic modelling for investigating dynamics of the soil C storage was used

  6. Carbon in boreal coniferous forest soil

    Energy Technology Data Exchange (ETDEWEB)

    Westman, C J; Ilvesniemi, H; Liski, J; Mecke, M [Helsinki Univ. (Finland). Dept. of Forest Ecology; Fritze, H; Helmisaari, H S; Pietikaeinen, J; Smolander, A [Finnish Forest Research Inst., Vantaa (Finland)

    1997-12-31

    The working hypothesis of the research was that the soil of boreal forests is a large carbon store and the amount of C is still increasing in young soils, like in the forest soils of Finland, which makes these soils important sinks for atmospheric CO{sub 2}. Since the processes defining the soil C balance, primary production of plants and decomposition, are dependent on environmental factors and site properties, it was assumed that the organic carbon pool in the soil is also dependent on the same factors. The soil C store is therefore likely to change in response to climatic warming. The aim of this research was to estimate the C balance of forest soil in Finland and predict changes in the balance in response to changes in climatic conditions. To achieve the aim (1) intensive empirical experimentation on the density of C in different pools in the soil and on fluxes between the pools was done was done, (2) the effect of site fertility and climate on the amount and properties of organic C in forest soil was investigated and (3) dynamic modelling for investigating dynamics of the soil C storage was used

  7. Seasonal quantitative dynamics and ecology of pelagic rotifers in an acidified boreal lake

    Directory of Open Access Journals (Sweden)

    Svein Birger Wærvågen

    2017-12-01

    Full Text Available Lake Gjerstadvann is a dimictic, oligotrophic, slightly acidified boreal lake in southern Norway (northwest Europe. The planktonic rotifer community of this lake was studied quantitatively during one year in order to investigate the impacts of the local environment and biotic interactions on seasonal succession and habitat selection. Pure suspension feeders (mainly Keratella spp., Conochilus spp., and Kellicottia longispina together with raptorial graspers or specialised feeders (mainly Polyarthra spp. and Collotheca spp. dominated the rotifer community over prolonged periods, whereas carnivorous/omnivorous species (mainly Asplanchna priodonta were extremely uncommon. Low bicarbonate buffering capacity resulted in a distinctive seasonal oscillating pH between 5.0 and 5.6, defining a special acid-transition lake category. The pH values were highest in the productive period during summer, and lowest during ice break-up coinciding with the peak reactive aluminium concentrations of 250-300 mg L-1. As in typical Norwegian boreal perch lakes, the most abundant cladoceran was Bosmina longispina due to perch predation on the genus Daphnia. Rotifer community structure was significantly related to temperature and oxygen (P=0.001 and P=0.022, illustrating the important effects of the seasonal cycle and vertical density stratification. The most significant competition indicator species were B. longispina and Eudiaptomus gracilis (both with P=0.001. A variance partitioning indicated that 14% of the total community composition variance could only be explained by biotic interactions, while 19% of the variance could be attributed to environmental gradients. Of the variance, 23% could not be resolved between biotic interactions and environmental gradients, while a residual of 44% was not explainable by any of the variables. Acid conditions alone cannot account for all the observed changes in the rotifer community of this lake with low humic content, since

  8. The role of emergent vegetation in structuring aquatic insect communities in peatland drainage ditches

    NARCIS (Netherlands)

    Whatley, M.H.; van Loon, E.E.; Vonk, J.A.; van der Geest, H.G.; Admiraal, W.

    2014-01-01

    Availability of macrophyte habitat is recognized as an important driver of aquatic insect communities in peatland drainage ditches; however, eutrophication can lead to the decline of submerged vegetation. While emergent vegetation is able to persist in eutrophicated ditches, vegetation removal,

  9. The long-term fate of permafrost peatlands under rapid climate warming

    DEFF Research Database (Denmark)

    Swindles, Graeme T.; Morris, Paul J.; Mullan, Donal

    2015-01-01

    Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon...... stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological...... approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed...

  10. Relationships between aquatic invertebrates, water quality and vegetation in an Andean peatland system

    Directory of Open Access Journals (Sweden)

    E. Oyague Passuni

    2015-12-01

    Full Text Available Peatlands (known as bofedales in the Peruvian Andes provide important social and environmental services in the Peruvian Puna ecoregion, especially as sources of water and forage for domestic livestock. In biological terms, these peatlands are key habitats with their own community structure, dynamics and interactions; and they serve as biodiversity hotspots within the High Andes. In this article we assess the relationships between: (i physical structure, (ii water quality, (iii plant communities and (iv the assemblages of aquatic invertebrates (benthic macroinvertebrates in three peatlands located in Cuzco Region, southern Peru. The results suggest that the benthic macroinvertebrate assemblage is a good indicator of the trophic status of the small pools that are typically present in bofedales. Trophic status is, in turn, primarily related to spatial and seasonal water availability and the types of plant communities present in each peatland.

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

    Czech Academy of Sciences Publication Activity Database

    Evans, C. D.; Page, S. E.; Jones, T.; Moore, S.; Gauci, V.; Laiho, R.; Hruška, Jakub; Allott, T. E. H.; Billet, M. F.; Tipping, E.; Freeman, Ch.; Garnett, M. H.

    2014-01-01

    Roč. 28, č. 11 (2014), s. 1215-1234 ISSN 0886-6236 Institutional support: RVO:67179843 Keywords : peatland * drainage * dissolved organic carbon * radiocarbon Subject RIV: EH - Ecology, Behaviour Impact factor: 3.965, year: 2014

  12. Peatland restoration in Canada by the sphagnum moss layer transfer method

    Energy Technology Data Exchange (ETDEWEB)

    Rochefort, L.; Boismenu, C. [Laval Univ., Quebec City, PQ (Canada). Dept. de Phytologie, Peatland Ecology and Research Group; Quinty, F. [SNC-Lavalin, Montreal, PQ (Canada)

    2009-04-01

    This article described a peatland restoration approach that has received international recognition for restoring the ecological functions of cutover sphagnum dominated peatlands. The Peatland Ecology Research Group (PERG) conducted a long-term study at the Bois-des-Bel (BDB) peatland site in Quebec to restore plant composition to a peat accumulating ecosystem. The sphagnum moss layer transfer restoration method includes 5 obligatory steps and one optional. These include planning; surface preparation; plant collection and spreading; straw mulch spreading; blocking drainage ditches; and fertilization if needed. Variable moisture conditions throughout the restoration site contribute to the spatial variability in the development of the sphagnum layer. The site has been monitored each year since its restoration. sphagnum cover reached 60 per cent in the restored zone in 2005, a value close to the range of sphagnum cover found in natural sites. In addition, a new moss layer has developed with an average of 25 cm in thickness. 27 refs., 4 figs.

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

    Science.gov (United States)

    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...

  14. Carbon sequestration in Southeast Asian tropical peatlands over the Holocene period: large-scale hydrological controls

    Science.gov (United States)

    Dommain, R.; Couwenberg, J.; Cobb, A.; Gandois, L.; Kai, F.; Su'ut, N.; Abu Salim, K.; Harvey, C. F.; Glaser, P. H.; Joosten, H.

    2012-12-01

    Tropical peatlands are recognized as a significant sink of carbon dioxide and an important source of methane. Low latitude peatlands contain an estimated pool of 90 Pg C, of which ca. 70 Pg C is stored in Southeast Asian peatlands. However, the Holocene development of this carbon reservoir is poorly established. Here we provide a synthesis of carbon uptake rates by tropical peatlands in Southeast Asia across millennial timescales for the past 11,000 years. Our reconstruction of the carbon accumulation history for Borneo, Sumatra and Peninsular Malaysia is based on a synthesis of radiocarbon dated peat profiles, modeling of peatland extent, and a new carbon accumulation record from Brunei (NW-Borneo). During the early Holocene the first peatlands formed in southern Borneo under the influence of a strong monsoon and rapid rise in sea-level. The carbon accumulation rate (CAR) in these peatlands was on average 60 g C m-2 yr-1 at this time. Peatlands started to spread across the coastal lowlands of Borneo, Sumatra and Peninsular Malaysia after 8000 cal BP only when the rate of rising sea-level decreased. The major phase of coastal peatland initiation lasted from 7000 to 4000 cal BP. This period was marked by a Holocene precipitation maximum, suppressed El Niño activity, and the Holocene maximum in sea-level on the Sunda Shelf. The mean CAR of coastal peatlands at this time was 80 g C m-2 yr-1, with a Holocene peak of ~100 g C m-2 yr-1 from 4900 to 4500 cal BP. Significantly, atmospheric CO2 concentrations measured in the Taylor Dome Antarctic ice core indicate a plateau during this period of otherwise rising CO2 concentrations. During the Late Holocene CAR declined both in coastal peatlands (ca. 70 g C m-2 yr-1) and in southern Borneo (ca. 20 g C m-2 yr-1) in response to falling sea-levels and increased El Niño frequency and intensity. In fact, several peatlands in southern Borneo have stopped accumulating peat-carbon under higher El Niño activity. These results

  15. Water and peat chemistry comparisons of natural and peat-harvested peatlands across Canada and their relevance to peatland restoration

    International Nuclear Information System (INIS)

    Windmulder, H.L.; Rochefort, L.; Vitt, D.H.

    1996-01-01

    Water and peat chemistry comparisons of four post-harvested and neighbouring, undisturbed peatlands across Canada show that harvesting alters chemical conditions. Commercial harvesting removes the surface peat and exposes layers farther down the peat deposit. The newly exposed peat layers that were formed in earlier developmental stages of the peatland can be more minerotrophic and/or more variable in chemical composition than undisturbed bog peat. All the harvested sites were originally bogs. Only one site, which had minimal peat removed, presently has chemical conditions somewhat similar to the original surface, with low elemental levels typical of bogs. Two sites are now chemically similar to poor fens and one site is similar to a moderate-rich fen. Levels of sodium, potassium, calcium, magnesium, sulphate and chloride in three of the harvested sites are higher than normal values found in natural, unharvested bogs, and result from the exposure of fen peat. Higher levels of ammonium-nitrogen and nitrate-nitrogen in the peat and water of all the harvested sites are present, with higher ammonium associated with wetter sites and higher nitrate levels associated with drier sites

  16. The role of drainage ditches in greenhouse gas emissions and surface leaching losses from a cutaway peatland cultivated with a perennial bioenergy crop

    Energy Technology Data Exchange (ETDEWEB)

    Hyvonen, N.P.; Huttunen, J.T.; Shurpali, N.J.; Lind, S.E.; Marushchak, M.E.; Martikainen, P.J. [University of Eastern Finland, Kuopio (Finland). Dept. of Environmental Science], E-mail: niina.hyvonen@uef.fi; Heitto, L. [Environmental Research of Savo-Karjala Ltd, Kuopio (Finland)

    2013-06-01

    We studied greenhouse gas (GHG) emissions from drainage ditches and leaching losses in a boreal cutaway peatland cultivated with reed canary grass (Phalaris arundinacea) for bioenergy. The objectives of the study were to assess to what extent GHG emissions from drainage ditches and leaching of carbon and nutrients via surface drainage contribute to the total losses of carbon and nitrogen from the site. The emissions of CH{sub 4}, N{sub 2}O and CO{sub 2} were measured with static chamber methods for three years and leaching losses for seven years. On average, the drainage ditches (covering 6% of the study site area) released 10% of the total CH{sub 4} emission (0.33 g m{sup -2} a{sup -1}), and 1% and 5% of the total N{sub 2}O and CO{sub 2} emissions, respectively. Leaching of total nitrogen and phosphorous were 0.31 and 0.03 g m{sup -2} a{sup -1}, respectively. Leaching values were lower than those reported for agricultural catchments in general. (orig.)

  17. Modelling hydrological processes and dissolved organic carbon dynamics in a rehabilitated Sphagnum-dominated peatland

    Science.gov (United States)

    Bernard-Jannin, Léonard; Binet, Stéphane; Gogo, Sébastien; Leroy, Fabien; Perdereau, Laurent; Laggoun-Défarge, Fatima

    2017-04-01

    Sphagnum-dominated peatlands represent a global major stock of carbon (C). Dissolved organic carbon (DOC) exports through runoff and leaching could reduce their potential C sink function and impact downstream water quality. DOC production in peatlands is strongly controlled by the hydrology, especially water table depth (WTD). Therefore, disturbances such as drainage can lead to increase DOC exports by lowering the WTD. Hydrological restoration (e.g. rewetting) can be undertaken to restore peatland functioning with an impact on DOC exports. The objective of this study is to assess the impact of drainage and rewetting on hydrological processes and their interactions with DOC dynamics in a Sphagnum dominated peatland. A hydrological model has been applied to a drained peatland (La Guette, France) which experienced a rewetting action on February 2014 and where WTD has been recorded in four piezometers at a 15 min time step since 2009. In addition, DOC concentrations in the peatland have been measured 6 times a year since 2014. The hydrological model is a WTD dependent reservoir model composed by two reservoirs representing the micro and macro porosity of the peatland (Binet et al., 2013). A DOC production module in both reservoirs was implemented based on temperature and WTD. The model was calibrated against WTD and DOC concentrations for each piezometer. The results show that the WTD in the study area is strongly affected by local meteorological conditions that could hide the effect of the rewetting action. The preliminary results evidenced that an additional source of water, identified as groundwater supply originating from the surrounding sandy layer aquifer, is necessary to maintain the water balance, especially during wet years (NS>0.8). Finally, the DOC module was able to describe DOC concentrations measured in the peatland and could be used to assess the impact of rewetting on DOC dynamics at different locations and to identify the factors of control of DOC

  18. Methylmercury dynamics at the upland-peatland interface: Topographic and hydrogeochemical controls

    Science.gov (United States)

    Carl P. J. Mitchell; Brian A. Branfireun; Randall K. Kolka

    2009-01-01

    Peatlands are important environments for the transformation of atmospherically deposited inorganic mercury into the bioaccumulative form, methylmercury (MeHg), which may accumulate in downstream aquatic biota, particularly in fish. In recent research, it was suggested that MeHg production and/or accumulation ‘‘hot spots’’ at the upland-peatland interface were the...

  19. Peatland carbon stocks and accumulation rates in the Ecuadorian páramo

    Science.gov (United States)

    John A. Hribljan; Esteban Suarez; Katherine A. Heckman; Erik Lilleskov; Rodney A. Chimner

    2016-01-01

    The páramo is a high altitude tropical Andean ecosystem that contains peatlands with thick horizons of carbon (C) dense soils. Soil C data are sparse for most of the pa´ramo, especially in peatlands, which limits our ability to provide accurate regional and country wide estimates of C storage. Therefore, the objective of our research was to quantify belowground C...

  20. Upscaling Our Approach to Peatland Carbon Sequestration: Remote Sensing as a Tool for Carbon Flux Estimation.

    Science.gov (United States)

    Lees, K.; Khomik, M.; Clark, J. M.; Quaife, T. L.; Artz, R.

    2017-12-01

    Peatlands are an important part of the Earth's carbon cycle, comprising approximately a third of the global terrestrial carbon store. However, peatlands are sensitive to climatic change and human mismanagement, and many are now degraded and acting as carbon sources. Restoration work is being undertaken at many sites around the world, but monitoring the success of these schemes can be difficult and costly using traditional methods. A landscape-scale alternative is to use satellite data in order to assess the condition of peatlands and estimate carbon fluxes. This work focuses on study sites in Northern Scotland, where parts of the largest blanket bog in Europe are being restored from forest plantations. A combination of laboratory and fieldwork has been used to assess the Net Ecosystem Exchange (NEE), Gross Primary Productivity (GPP) and respiration of peatland sites in different conditions, and the climatic vulnerability of key peat-forming Sphagnum species. The results from these studies have been compared with spectral data in order to evaluate the extent to which remote sensing can function as a source of information for peatland health and carbon flux models. This work considers particularly the effects of scale in calculating peatland carbon flux. Flux data includes chamber and eddy covariance measurements of carbon dioxide, and radiometric observations include both handheld spectroradiometer results and satellite images. Results suggest that despite the small-scale heterogeneity and unique ecosystem factors in blanket bogs, remote sensing can be a useful tool in monitoring peatland health and carbon sequestration. In particular, this study gives unique insights into the relationships between peatland vegetation, carbon flux and spectral reflectance.

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

    Science.gov (United States)

    Schoning, Kristian; Sohlenius, Gustav

    2016-04-01

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

  2. Denial of long-term issues with agriculture on tropical peatlands will have devastating consequences

    OpenAIRE

    Wijedasa, Lahiru S.; Jauhiainen, Jyrki; Könönen, Mari; Lampela, Maija; Vasander, Harri; Leblanc, Marie-Claire; Evers, Stephanie; Smith, E. L. Thomas; Yule, Catherine M.; Varkkey, Helena; Lupascu, Massimo; Parish, Faizal; Singleton, Ian; Clements, Gopalasamy R.; Aziz, Sheema Abdul

    2017-01-01

    The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought together over 1000 international peatland scientists and industrial partners from across the world (“International Peat Congress with over 1000 participants!,” 2016). The congress covered all aspects of peatland ecosystems and their management, with a strong focus on the environmental, societal and economic challenges associated with contemporary large-scale agricultural conversion of tropical pe...

  3. Groundwater dynamics in mountain peatlands with contrasting climate, vegetation, and hydrogeological setting

    Science.gov (United States)

    Millar, David J.; Cooper, David J.; Ronayne, Michael J.

    2018-06-01

    Hydrological dynamics act as a primary control on ecosystem function in mountain peatlands, serving as an important regulator of carbon fluxes. In western North America, mountain peatlands exist in different hydrogeological settings, across a range climatic conditions, and vary in floristic composition. The sustainability of these ecosystems, particularly those at the low end of their known elevation range, is susceptible to a changing climate via changes in the water cycle. We conducted a hydrological investigation of two mountain peatlands, with differing vegetation, hydrogeological setting (sloping vs basin), and climate (strong vs weak monsoon influence). Growing season saturated zone water budgets were modeled on a daily basis, and subsurface flow characterizations were performed during multiple field campaigns at each site. The sloping peatland expectedly showed a strong lateral groundwater potential gradient throughout the growing season. Alternatively, the basin peatland had low lateral gradients but more pronounced vertical gradients. A zero-flux plane was apparent at a depth of approximately 50 cm below the peat surface at the basin peatland; shallow groundwater above this depth moved upward towards the surface via evapotranspiration. The differences in groundwater flow dynamics between the two sites also influenced water budgets. Higher groundwater inflow at the sloping peatland offset higher rates of evapotranspiration losses from the saturated zone, which were apparently driven by differences in vegetative cover. This research revealed that although sloping peatlands cover relatively small portions of mountain watersheds, they provide unique settings where vegetation directly utilizes groundwater for transpiration, which were several-fold higher than typically reported for surrounding uplands.

  4. Improving Water Quality With Conservation Buffers

    Science.gov (United States)

    Lowrance, R.; Dabney, S.; Schultz, R.

    2003-12-01

    Conservation buffer technologies are new approaches that need wider application. In-field buffer practices work best when used in combination with other buffer types and other conservation practices. Vegetative barriers may be used in combination with edge-of-field buffers to protect and improve their function and longevity by dispersing runoff and encouraging sediment deposition upslope of the buffer. It's important to understand how buffers can be managed to help reduce nutrient transport potential for high loading of nutrients from manure land application sites, A restored riparian wetland buffer retained or removed at least 59 percent of the nitrogen and 66 percent of the phosphorus that entered from an adjacent manure land application site. The Bear Creek National Restoration Demonstration Watershed project in Iowa has been the site of riparian forest buffers and filter strips creation; constructed wetlands to capture tile flow; stream-bank bioengineering; in-stream structures; and controlling livestock grazing. We need field studies that test various widths of buffers of different plant community compositions for their efficacy in trapping surface runoff, reducing nonpoint source pollutants in subsurface waters, and enhancing the aquatic ecosystem. Research is needed to evaluate the impact of different riparian grazing strategies on channel morphology, water quality, and the fate of livestock-associated pathogens and antibiotics. Integrating riparian buffers and other conservation buffers into these models is a key objective in future model development.

  5. Buffered Communication Analysis in Distributed Multiparty Sessions

    Science.gov (United States)

    Deniélou, Pierre-Malo; Yoshida, Nobuko

    Many communication-centred systems today rely on asynchronous messaging among distributed peers to make efficient use of parallel execution and resource access. With such asynchrony, the communication buffers can happen to grow inconsiderately over time. This paper proposes a static verification methodology based on multiparty session types which can efficiently compute the upper bounds on buffer sizes. Our analysis relies on a uniform causality audit of the entire collaboration pattern - an examination that is not always possible from each end-point type. We extend this method to design algorithms that allocate communication channels in order to optimise the memory requirements of session executions. From these analyses, we propose two refinements methods which respect buffer bounds: a global protocol refinement that automatically inserts confirmation messages to guarantee stipulated buffer sizes and a local protocol refinement to optimise asynchronous messaging without buffer overflow. Finally our work is applied to overcome a buffer overflow problem of the multi-buffering algorithm.

  6. A THEORETICAL DISCUSSION OF THE ECONOMIC EFFECTS OF BUFFER STOCKS AND BUFFER FUNDS

    OpenAIRE

    Simmons, Phil

    1988-01-01

    It has been established that the absence of risk markets justifies market intervention in principle. The form of intervention that has been discussed most widely in the literature is the buffer stock. This paper points out that other forms of intervention, specifically buffer funds, are likely to perform better. The analysis shows that buffer funds are likely to outperform buffer stocks because they address market failure more directly. A sub-theme developed in this paper is that since buffer...

  7. The changing effects of Alaska's boreal forest on the climate system

    Science.gov (United States)

    E.S. Euskirchen; A.D. McGuire; F.S. Chapin; T.S. Rupp

    2010-01-01

    In the boreal forests of Alaska, recent changes in climate have influenced the exchange of trace gases, water, and energy between these forests and the atmosphere. These changes in the structure and function of boreal forests can then feed back to impact regional and global climates. We examine the type and magnitude of the climate feedbacks from boreal forests in...

  8. Population structure and genetic diversity in North American Hedysarum boreale Nutt.

    Science.gov (United States)

    Bradley S. Bushman; Steven R. Larson; Michael D. Peel; Michael E. Pfrender

    2007-01-01

    Hedysarum boreale Nutt. is a perennial legume native to western North America, with robust foliage in the late spring season. Due to its wide native range, forage value, and N2 fixation, H. boreale is of interest for rangeland revegetation and production. Seed cost is a major obstacle for utilization of H. boreale, primarily due to seed shattering and unreliable seed...

  9. Fungal communities in ancient peatlands developed from different periods in the Sanjiang Plain, China.

    Science.gov (United States)

    Zhang, Zhenqing; Zhou, Xue; Tian, Lei; Ma, Lina; Luo, Shasha; Zhang, Jianfeng; Li, Xiujun; Tian, Chunjie

    2017-01-01

    Peatlands in the Sanjiang Plain could be more vulnerable to global warming because they are located at the southernmost boundary of northern peatlands. Unlike bacteria, fungi are often overlooked, even though they play important roles in substance circulation in the peatland ecosystems. Accordingly, it is imperative that we deepen our understanding of fungal community structure and diversity in the peatlands. In this study, high-throughput Illumina sequencing was used to study the fungal communities in three fens in the Sanjiang Plain, located at the southern edge of northern peatlands. Peat soil was collected from the three fens which developed during different periods. A total of 463,198 fungal ITS sequences were obtained, and these sequences were classified into at least six phyla, 21 classes, more than 60 orders and over 200 genera. The fungal community structures were distinct in the three sites and were dominated by Ascomycota and Basidiomycota. However, there were no significant differences between these three fens in any α-diversity index (p > 0.05). Soil age and the carbon (C) accumulation rate, as well as total carbon (TC), total nitrogen (TN), C/N ratio, and bulk density were found to be closely related to the abundance of several dominant fungal taxa. We captured a rich fungal community and confirmed that the dominant taxa were those which were frequently detected in other northern peatlands. Soil age and the C accumulation rate were found to play important roles in shaping the fungal community structure.

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

    Science.gov (United States)

    Whittle, Alex; Gallego-Sala, Angela V.

    2016-06-01

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

  11. Net ecosystem CO2 exchange of a cutover peatland rehabilitated with a transplanted acrotelm

    International Nuclear Information System (INIS)

    Cagampan, J.P.; Waddington, J.M.

    2008-01-01

    Peatlands are an important long-term sink for atmospheric carbon dioxide (CO 2 ). The storage function of peatland ecosystems is significantly impacted by drainage and extraction processes, which can result in the release of significant amounts of CO 2 . This paper investigated the net ecosystem CO 2 exchange of a newly developed extraction-restoration technique that preserved the acrotelm and replaced it directly on the cut surface of the peatlands. The technique used a modified block-cut method with a back-hoe to create a drainage ditch. Actrotelm and surface vegetation were removed and placed to one side, and the peat was mechanically removed. The acrotelm was then transplanted over the older and more decomposed catotelm peat to create a trench topography in which the natural peatland was higher than the extracted zone. Air temperatures, water table levels, and volumetric moisture content levels were measured throughout the experiment. Measurements of CO 2 exchange were taken for the duration of a Spring and summer growing season at 12 sampling locations. Results of the experiment showed that the technique was successful in maintaining moisture conditions similar to those observed in the natural peatlands. However, the peatlands where the technique was used were still net emitters of CO 2 . Recommendations for improving the technique included using more care when removing upper peat layers; limiting surface damage; and reducing spaces and gaps between the transplanted acrotelm. 34 refs., 8 figs

  12. A survey of ASEAN instruments relating to peatlands, mangroves and other wetlands: The REDD+ context

    Directory of Open Access Journals (Sweden)

    Kheng-Lian Koh

    2013-07-01

    Full Text Available Since the 13th Association of Southeast Asian Nations (ASEAN Summit in November 2007, held in Singapore, ASEAN has accelerated its response to climate change issues, including REDD+ as a mechanism for climate change mitigation and adaptation, and to enhance conservation and sustainable use of natural resources. There are many wetlands in ASEAN including more than 25 million ha of peatlands spread over Indonesia, Malaysia, Thailand, Brunei, Philippines, Vietnam and Lao PDR. The peatlands account for 60 per cent of global tropical peatland resources. They are of significance for sequestration of carbon. However, degraded wetlands, including peatlands, are also a major source of greenhouse gases contributing to global warming. Of the types of wetlands, ASEAN has focused attention predominantly on peatlands in relation to REDD+, mainly because of the ‘Indonesian Haze’. The Asia-Pacific Centre for Environmental Law (APCEL organised a Workshop titled, REDD+ and Legal Regimes of Mangroves, Peatland and Other Wetlands: ASEAN and the World, in Singapore from 15-16 November 2012. The articles contained in this special themed edition of the International Journal of Rural Law and Policy (IJRLP contains a selection of the papers presented. This editorial will provide a brief background to some aspects of REDD+. Included in this issue of IJRLP is a summary of the proceedings of the workshop as interpreted by the assigned rapporteur and editors of APCEL. These summaries were reviewed and approved by the presenters.

  13. Response of testate amoebae to a late Holocene ecosystem shift in an Amazonian peatland.

    Science.gov (United States)

    Swindles, Graeme T; Kelly, Thomas J; Roucoux, Katherine H; Lawson, Ian T

    2018-03-15

    To date there have only been two studies using testate amoebae as palaeoecological indicators in tropical peatlands. Here we present a new ∼500-year testate amoeba record from San Jorge, a domed peatland in Peruvian Amazonia, which has a well-constrained vegetation history based on pollen analysis. We observe a major shift from Hyalosphenia subflava to Cryptodifflugia oviformis-dominated communities at ∼50 cm depth (c. AD 1760), which suggests a change to drier conditions in the peatland. The application of a statistical transfer function also suggests a deepening of the water table at this time. The transition in the microbial assemblage occurs at a time when pollen and geochemical data indicate drier conditions (reduced influence of river flooding), leading to an ecosystem switch to more ombrotrophic-like conditions in the peatland. Our work illustrates the potential of testate amoebae as important tools in tropical peatland palaeoecology, and the power of multiproxy approaches for understanding the long-term development of tropical peatlands. Copyright © 2018 Elsevier GmbH. All rights reserved.

  14. Fungal communities in ancient peatlands developed from different periods in the Sanjiang Plain, China.

    Directory of Open Access Journals (Sweden)

    Zhenqing Zhang

    Full Text Available Peatlands in the Sanjiang Plain could be more vulnerable to global warming because they are located at the southernmost boundary of northern peatlands. Unlike bacteria, fungi are often overlooked, even though they play important roles in substance circulation in the peatland ecosystems. Accordingly, it is imperative that we deepen our understanding of fungal community structure and diversity in the peatlands. In this study, high-throughput Illumina sequencing was used to study the fungal communities in three fens in the Sanjiang Plain, located at the southern edge of northern peatlands. Peat soil was collected from the three fens which developed during different periods. A total of 463,198 fungal ITS sequences were obtained, and these sequences were classified into at least six phyla, 21 classes, more than 60 orders and over 200 genera. The fungal community structures were distinct in the three sites and were dominated by Ascomycota and Basidiomycota. However, there were no significant differences between these three fens in any α-diversity index (p > 0.05. Soil age and the carbon (C accumulation rate, as well as total carbon (TC, total nitrogen (TN, C/N ratio, and bulk density were found to be closely related to the abundance of several dominant fungal taxa. We captured a rich fungal community and confirmed that the dominant taxa were those which were frequently detected in other northern peatlands. Soil age and the C accumulation rate were found to play important roles in shaping the fungal community structure.

  15. Groundwater flow in a coastal peatland and its influence on submarine groundwater discharge

    Science.gov (United States)

    Ptak, T.; Ibenthal, M.; Janssen, M.; Massmann, G.; Lenartz, B.

    2017-12-01

    Coastal peatlands are characterized by intense interactions between land and sea, comprising both a submarine discharge of fresh groundwater and inundations of the peatland with seawater. Nutrients and salts can influence the biogeochemical processes both in the shallow marine sediments and in the peatland. The determination of flow direction and quantity of groundwater flow are therefore elementary. Submarine groundwater discharge (SGD) has been reported from several locations in the Baltic. The objective of this study is to quantify the exchange of fresh and brackish water across the shoreline in a coastal peatland in Northeastern Germany, and to assess the influence of a peat layer extending into the Baltic Sea. Below the peatland, a shallow fine sand aquifer differs in depth and is limited downwards by glacial till. Water level and electrical conductivity (EC) are permanently measured in different depths at eight locations in the peatland. First results indicate a general groundwater flow direction towards the sea. Electrical conductivity measurements suggest different permeabilities within the peat layer, depending on its thickness and degradation. Near the beach, EC fluctuates partially during storm events due to seawater intrusion and reverse discharge afterwards. The groundwater flow will be verified with a 3D model considering varying thicknesses of the aquifer. Permanent water level and electrical conductivity readings, meteorological data and hydraulic conductivity from slug tests and grain size analysis are the base for the calibration of the numerical model.

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

    Science.gov (United States)

    Whittle, Alex; Gallego-Sala, Angela V.

    2016-01-01

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

  17. Short-term vegetation change on rehabilitated peatland on Rietvlei Nature Reserve

    Directory of Open Access Journals (Sweden)

    C.E. Venter

    2003-12-01

    Full Text Available Natural peatlands occur on the Rietvlei Nature Reserve. Before the Pretoria City Council acquired the land, these peatlands were mined by private land-owners. Ditches were constructed to drain the area for mining and the peatlands became desicrated. Later the area was proclaimed as a nature reserve and has since then been managed as such. Rehabilitation of the drained peatland on Rietvlei Nature Reserve first started in 2000 as a Working for Water project. The aim of the rehabilitation was to close the ditches and rewet the peatland, to enable possible revival of the peatland. A baseline vegetation survey was undertaken during the summer (March to April of 2001 to determine the nature of the pioneer communities that established on the rehabilitated area. This survey was repeated during the summer (March to April of 2002 to detect changes in the vegetation. The same sample plots were used on both occasions. The initial pioneer vegetation was mostly composed of weedy annuals.

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

    Science.gov (United States)

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

    2014-11-01

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

  19. Fungal communities in ancient peatlands developed from different periods in the Sanjiang Plain, China

    Science.gov (United States)

    Tian, Lei; Ma, Lina; Luo, Shasha; Zhang, Jianfeng; Li, Xiujun

    2017-01-01

    Peatlands in the Sanjiang Plain could be more vulnerable to global warming because they are located at the southernmost boundary of northern peatlands. Unlike bacteria, fungi are often overlooked, even though they play important roles in substance circulation in the peatland ecosystems. Accordingly, it is imperative that we deepen our understanding of fungal community structure and diversity in the peatlands. In this study, high-throughput Illumina sequencing was used to study the fungal communities in three fens in the Sanjiang Plain, located at the southern edge of northern peatlands. Peat soil was collected from the three fens which developed during different periods. A total of 463,198 fungal ITS sequences were obtained, and these sequences were classified into at least six phyla, 21 classes, more than 60 orders and over 200 genera. The fungal community structures were distinct in the three sites and were dominated by Ascomycota and Basidiomycota. However, there were no significant differences between these three fens in any α-diversity index (p > 0.05). Soil age and the carbon (C) accumulation rate, as well as total carbon (TC), total nitrogen (TN), C/N ratio, and bulk density were found to be closely related to the abundance of several dominant fungal taxa. We captured a rich fungal community and confirmed that the dominant taxa were those which were frequently detected in other northern peatlands. Soil age and the C accumulation rate were found to play important roles in shaping the fungal community structure. PMID:29236715

  20. Biased representation of disturbance rates in the roadside sampling frame in boreal forests: implications for monitoring design

    Directory of Open Access Journals (Sweden)

    Steven L. Van Wilgenburg

    2015-12-01

    Full Text Available The North American Breeding Bird Survey (BBS is the principal source of data to inform researchers about the status of and trend for boreal forest birds. Unfortunately, little BBS coverage is available in the boreal forest, where increasing concern over the status of species breeding there has increased interest in northward expansion of the BBS. However, high disturbance rates in the boreal forest may complicate roadside monitoring. If the roadside sampling frame does not capture variation in disturbance rates because of either road placement or the use of roads for resource extraction, biased trend estimates might result. In this study, we examined roadside bias in the proportional representation of habitat disturbance via spatial data on forest "loss," forest fires, and anthropogenic disturbance. In each of 455 BBS routes, the area disturbed within multiple buffers away from the road was calculated and compared against the area disturbed in degree blocks and BBS strata. We found a nonlinear relationship between bias and distance from the road, suggesting forest loss and forest fires were underrepresented below 75 and 100 m, respectively. In contrast, anthropogenic disturbance was overrepresented at distances below 500 m and underrepresented thereafter. After accounting for distance from road, BBS routes were reasonably representative of the degree blocks they were within, with only a few strata showing biased representation. In general, anthropogenic disturbance is overrepresented in southern strata, and forest fires are underrepresented in almost all strata. Similar biases exist when comparing the entire road network and the subset sampled by BBS routes against the amount of disturbance within BBS strata; however, the magnitude of biases differed. Based on our results, we recommend that spatial stratification and rotating panel designs be used to spread limited BBS and off-road sampling effort in an unbiased fashion and that new BBS routes

  1. Subsidence and carbon loss in drained tropical peatlands

    Directory of Open Access Journals (Sweden)

    A. Hooijer

    2012-03-01

    Full Text Available Conversion of tropical peatlands to agriculture leads to a release of carbon from previously stable, long-term storage, resulting in land subsidence that can be a surrogate measure of CO2 emissions to the atmosphere. We present an analysis of recent large-scale subsidence monitoring studies in Acacia and oil palm plantations on peatland in SE Asia, and compare the findings with previous studies. Subsidence in the first 5 yr after drainage was found to be 142 cm, of which 75 cm occurred in the first year. After 5 yr, the subsidence rate in both plantation types, at average water table depths of 0.7 m, remained constant at around 5 cm yr−1. The results confirm that primary consolidation contributed substantially to total subsidence only in the first year after drainage, that secondary consolidation was negligible, and that the amount of compaction was also much reduced within 5 yr. Over 5 yr after drainage, 75 % of cumulative subsidence was caused by peat oxidation, and after 18 yr this was 92 %. The average rate of carbon loss over the first 5 yr was 178 t CO2eq ha−1 yr−1, which reduced to 73 t CO2eq ha−1 yr−1 over subsequent years, potentially resulting in an average loss of 100 t CO2eq ha−1 yr−1 over 25 yr. Part of the observed range in subsidence and carbon loss values is explained by differences in water table depth, but vegetation cover and other factors such as addition of fertilizers also influence peat oxidation. A relationship with groundwater table depth shows that subsidence and carbon loss are still considerable even at the highest water levels theoretically possible in plantations. This implies that improved plantation water management will reduce these impacts by 20 % at most, relative to current conditions, and that high rates of carbon loss and land subsidence are

  2. Aerosol volatility in a boreal forest environment

    Science.gov (United States)

    Häkkinen, S. A. K.; ńijälä, M.; Lehtipalo, K.; Junninen, H.; Virkkula, A.; Worsnop, D. R.; Kulmala, M.; Petäjä, T.; Riipinen, I.

    2012-04-01

    Climate and health effects of atmospheric aerosols are determined by their properties such as their chemical composition. Aerosol chemical composition can be studied indirectly by measuring volatility of aerosol particles. The volatility of submicron aerosol particles (20-500 nm) was studied in a boreal forest site at SMEAR II (Station for Measuring Ecosystem-Atmosphere Relations II) station (Vesala et al., 1998) in Hyytiälä, Finland, during 01/2008-05/2010. The instrument used for the measurements was VDMPS (Volatility Differential Mobility Particle Sizer), which consists of two separate instruments: DMPS (Differential Mobility Particle Sizer, Aalto et al., 2001) and TD (Thermodenuder, Wehner et al., 2002). Aerosol evaporation was examined by heating the aerosol and comparing the total aerosol mass before and after heating. In the VDMPS system ambient aerosol sample was heated up to temperatures ranging from 80 °C to 280 °C. The higher the heating temperature was the more aerosol material was evaporated. There was a non-volatile residual present in aerosol particles when heated up to 280 °C. This residual explained (20±8)% of the total aerosol mass. Aerosol non-volatile mass fraction was highest during winter and smallest during summer months. The role of black carbon in the observed non-volatile residual was determined. Black carbon explained 40 to 90% of the non-volatile mass. Especially during colder seasons noticeable amount of non-volatile material, something else than black carbon, was observed. According to Kalberer et al. (2004) some atmospheric organic species can form polymers that have high evaporation temperatures. Also low-volatile organic salts may contribute to the non-volatile aerosol (Smith et al., 2010). Aerosol mass composition measured directly with AMS (Aerosol Mass Spectrometer, Jayne et al., 2000) was analyzed in order to examine the properties of the non-volatile material (other than black carbon). The AMS measurements were performed

  3. Using 13C isotopes to explore denitrification-dependent anaerobic methane oxidation in a paddy-peatland.

    Science.gov (United States)

    Shi, Yao; Wang, Zhongqiang; He, Chunguang; Zhang, Xinyu; Sheng, Lianxi; Ren, Xiaodong

    2017-01-18

    Peatlands are organic-matter-rich but nitrogen-limited natural systems, the carbon/nitrogen (C/N) status of which are subject to increasing exposure from long-term nitrate (NO 3 - ) fertilizer inputs and atmospheric nitrogen (N) deposits. To manage and protect these unique environments, an improved understanding of denitrification-dependent anaerobic oxidation of methane (DAMO) in peatlands is needed. In this study, we used stable isotope measurements and incubation with NO 3 - additions to facilitate an investigation and comparison of the potential DAMO rates in a paddy-peatland that has been influenced by N fertilizer over 40 years and an undisturbed peatland in northeast China. Monitoring of 13 CO 2 production confimed DAMO did occur in both the paddy-peatland and the undisturbed peatland, the rates of which increased with NO 3 - additions, but decreased logarithmically with time. When NO 3 - was added, there were no significant differences between the CH 4 oxidation in the paddy-peatland and peatland samples after 36 hours of incubation (97.08 vs. 143.69 nmol g -1 dry peat) and the potential DAMO rate after incubation for 1 hour (92.53 vs. 69.99 nmol g -1  h -1 ). These results indicate that the occurrence of DAMO in peatlands might be controlled by the amount of NO 3 - applied and the depth to which it penetrates into the anoxic layer.

  4. Competitive interactions among raptors in boreal forests.

    Science.gov (United States)

    Hakkarainen, Harri; Mykrä, Sakari; Kurki, Sami; Tornberg, Risto; Jungell, Sven

    2004-11-01

    We examined inter-specific interactions among goshawks ( Accipiter gentilis), common buzzards (Buteo buteo) and honey buzzards (Pernis apivorus) in western Finland in 1983-1996. Because goshawks are among the largest birds of prey species in boreal forests they may take over the nest of smaller and less-competitive forest-dwelling raptors when searching for suitable places for breeding. Accordingly, more than half of newly established goshawk territories were found on the territories previously occupied by the common buzzard and the honey buzzard. Otherwise, territory sharing between these species was rare. Fledgling production of honey buzzards was not associated with the presence of goshawks, probably owing to the almost 2 months later onset of breeding. This probably decreases competitive interactions between these two species. An intensive interference competition, instead, seemed to be evident between common buzzards and goshawks, because the fledgling production of common buzzards was decreased by 20% as a result of failures during incubation and nestling period in the vicinity (nests. Similarly, territory occupancy of common buzzards till the next breeding season was significantly reduced in the presence of goshawks. Relatively high proportions of occupied buzzard territories (17%) in the study area were shared by breeding goshawks on the same territory. This suggests that although their diets are dissimilar they inhabit similar habitats and might compete for the available prime nesting habitats within forest landscapes. In addition, goshawks benefit from taking over the complete nests of other raptors, imposing upon the original owners of the nest, because building a large stick nest is probably energetically costly. As a large raptor, the goshawk apparently has a competitive advantage over smaller ones, and may have an ever-increasing impact on smaller birds of prey, if there is a lack of sheltered forests inducing competition for the available nest sites.

  5. Buffered Electrochemical Polishing of Niobium

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tian, Hui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States); Corcoran, Sean [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2011-03-01

    The standard preparation of superconducting radio-frequency (SRF) cavities made of pure niobium include the removal of a 'damaged' surface layer, by buffered chemical polishing (BCP) or electropolishing (EP), after the cavities are formed. The performance of the cavities is characterized by a sharp degradation of the quality factor when the surface magnetic field exceeds about 90 mT, a phenomenon referred to as 'Q-drop.' In cavities made of polycrystalline fine grain (ASTM 5) niobium, the Q-drop can be significantly reduced by a low-temperature (? 120 °C) 'in-situ' baking of the cavity if the chemical treatment was EP rather than BCP. As part of the effort to understand this phenomenon, we investigated the effect of introducing a polarization potential during buffered chemical polishing, creating a process which is between the standard BCP and EP. While preliminary results on the application of this process to Nb cavities have been previously reported, in this contribution we focus on the characterization of this novel electrochemical process by measuring polarization curves, etching rates, surface finish, electrochemical impedance and the effects of temperature and electrolyte composition. In particular, it is shown that the anodic potential of Nb during BCP reduces the etching rate and improves the surface finish.

  6. The impact of boreal forest fire on climate warming

    Science.gov (United States)

    Randerson, J.T.; Liu, H.; Flanner, M.G.; Chambers, S.D.; Jin, Y.; Hess, P.G.; Pfister, G.; Mack, M.C.; Treseder, K.K.; Welp, L.R.; Chapin, F.S.; Harden, J.W.; Goulden, M.L.; Lyons, E.; Neff, J.C.; Schuur, E.A.G.; Zender, C.S.

    2006-01-01

    We report measurements and analysis of a boreal forest fire, integrating the effects of greenhouse gases, aerosols, black carbon deposition on snow and sea ice, and postfire changes in surface albedo. The net effect of all agents was to increase radiative forcing during the first year (34 ?? 31 Watts per square meter of burned area), but to decrease radiative forcing when averaged over an 80-year fire cycle (-2.3 ?? 2.2 Watts per square meter) because multidecadal increases in surface albedo had a larger impact than fire-emitted greenhouse gases. This result implies that future increases in boreal fire may not accelerate climate warming.

  7. Carbonaceous aerosols from prescribed burning of a boreal forest ecosystem

    International Nuclear Information System (INIS)

    Mazurek, M.A.; Cofer, W.R. III; Levine, J.S.

    1991-01-01

    Smoke aerosol and background aerosol particles were collected from the controlled burning of boreal forest where vegetation species and relative mass distributions are known. Chemical mass balances were constructed for the total mass of carbonaceous aerosol particles emitted during the prescribed burn. In addition, a carbonaceous species inventory was developed for aerosol particles presnt under background, smoldering, and full-fire conditions; the production of organic carbon and elemental carbon particles is noted for these two fire regimes. Distributions of the solvent-soluble organic components of the sampled aerosols were generated to identify molecular properties that can be traced to unburned and pyrolyzed materials present in the boreal forest fuels

  8. The impact of boreal forest fire on climate warming.

    Science.gov (United States)

    Randerson, J T; Liu, H; Flanner, M G; Chambers, S D; Jin, Y; Hess, P G; Pfister, G; Mack, M C; Treseder, K K; Welp, L R; Chapin, F S; Harden, J W; Goulden, M L; Lyons, E; Neff, J C; Schuur, E A G; Zender, C S

    2006-11-17

    We report measurements and analysis of a boreal forest fire, integrating the effects of greenhouse gases, aerosols, black carbon deposition on snow and sea ice, and postfire changes in surface albedo. The net effect of all agents was to increase radiative forcing during the first year (34 +/- 31 Watts per square meter of burned area), but to decrease radiative forcing when averaged over an 80-year fire cycle (-2.3 +/- 2.2 Watts per square meter) because multidecadal increases in surface albedo had a larger impact than fire-emitted greenhouse gases. This result implies that future increases in boreal fire may not accelerate climate warming.

  9. Quantifying climatic impacts on peatland in the Zoige basin, China

    Science.gov (United States)

    Gao, P.; Li, Z.; Hu, X.

    2017-12-01

    Actual evapotranspiration (ET) of the Zoige basin in the Yellow River source region of China is a critical parameter for understanding water balance of peatland in the Zoige basin and hence the cause of the changing land cover. Using daily meteorological data sets of Zoige, Hongyuan, and Maqu stations from 1967 to 2011, the well-known FAO56 Penman-Monteith (P-M) formula was selected to calculate the reference crop evapotranspiration (ET0) in combination with the crop coefficient method in which the crop coefficient Kc is modified in terms of local climatic conditions. By classifying land cover of the Zoige basin in to swamp, grassland, water surface, and desert, the actual ET cover time for each type was obtained. Since late 1990s, the ET0 increased along with the increased air temperature. Different from previous studies, the ET of the swamp was slightly lower than that of water surface, but was slightly larger than the difference between annual precipitation and runoff in the Zoige basin. The increase of ET in the past 45 years was small in comparison with the change of the annual precipitation. More specifically, the annual precipitation, which was about 560-860 mm, slightly decreased between 1967 and 1997, and increased 2.23% in the 1998-2011 period. These results allowed us to conclude that though the slightly increased ET might be a factor leading to the long-term swamp dewatering, it cannot be the primary cause of the degraded peatland swamp and grassland in the Zoige basin.

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

    Science.gov (United States)

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

    2016-04-01

    Tropical peatland fires play a significant role in the context of global warming through emissions of substantial amounts of greenhouse gases. However, the state of knowledge on carbon loss from these fires is still poorly developed with few studies reporting the associated mass of peat consumed. Furthermore, spatial and temporal variations in burn depth have not been previously quantified. This study presents the first spatially explicit investigation of fire-driven tropical peat loss and its variability. An extensive airborne Light Detection and Ranging data set was used to develop a prefire peat surface modelling methodology, enabling the spatially differentiated quantification of burned area depth over the entire burned area. We observe a strong interdependence between burned area depth, fire frequency and distance to drainage canals. For the first time, we show that relative burned area depth decreases over the first four fire events and is constant thereafter. Based on our results, we revise existing peat and carbon loss estimates for recurrent fires in drained tropical peatlands. We suggest values for the dry mass of peat fuel consumed that are 206 t ha(-1) for initial fires, reducing to 115 t ha(-1) for second, 69 t ha(-1) for third and 23 t ha(-1) for successive fires, which are 58-7% of the current IPCC Tier 1 default value for all fires. In our study area, this results in carbon losses of 114, 64, 38 and 13 t C ha(-1) for first to fourth fires, respectively. Furthermore, we show that with increasing proximity to drainage canals both burned area depth and the probability of recurrent fires increase and present equations explaining burned area depth as a function of distance to drainage canal. This improved knowledge enables a more accurate approach to emissions accounting and will support IPCC Tier 2 reporting of fire emissions. © 2015 John Wiley & Sons Ltd.

  11. PEAT-CO2. Assessment of CO2 emissions from drained peatlands in SE Asia

    International Nuclear Information System (INIS)

    Hooijer, A.; Silvius, M.; Woesten, H.; Page, S.

    2006-12-01

    Forested tropical peatlands in SE Asia store at least 42,000 Megatonnes of soil carbon. This carbon is increasingly released to the atmosphere due to drainage and fires associated with plantation development and logging. Peatlands make up 12% of the SE Asian land area but account for 25% of current deforestation. Out of 27 million hectares of peatland, 12 million hectares (45%) are currently deforested and mostly drained. One important crop in drained peatlands is palm oil, which is increasingly used as a biofuel in Europe. In the PEAT-CO2 project, present and future emissions from drained peatlands were quantified using the latest data on peat extent and depth, present and projected land use and water management practice, decomposition rates and fire emissions. It was found that current likely CO2 emissions caused by decomposition of drained peatlands amounts to 632 Mt/y (between 355 and 874 Mt/y). This emission will increase in coming decades unless land management practices and peatland development plans are changed, and will continue well beyond the 21st century. In addition, over 1997-2006 an estimated average of 1400 Mt/y in CO2 emissions was caused by peatland fires that are also associated with drainage and degradation. The current total peatland CO2 emission of 2000 Mt/y equals almost 8% of global emissions from fossil fuel burning. These emissions have been rapidly increasing since 1985 and will further increase unless action is taken. Over 90% of this emission originates from Indonesia, which puts the country in 3rd place (after the USA and China) in the global CO2 emission ranking. It is concluded that deforested and drained peatlands in SE Asia are a globally significant source of CO2 emissions and a major obstacle to meeting the aim of stabilizing greenhouse gas emissions, as expressed by the international community. It is therefore recommended that international action is taken to help SE Asian countries, especially Indonesia, to better conserve

  12. Development of biogenic VOC emission inventories for the boreal forest

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, V.

    2008-07-01

    The volatile organic compounds (VOCs) emitted by vegetation, especially forests, can affect local and regional atmospheric photochemistry through their reactions with atmospheric oxidants. Their reaction products may also participate in the formation and growth of new particles which affect the radiation balance of the atmosphere, and thus climate, by scattering and absorbing shortwave and longwave radiation and by modifying the radiative properties, amount and lifetime of clouds. Globally, anthropogenic VOC emissions are far surpassed by the biogenic ones, making biogenic emission inventories an integral element in the development of efficient air quality and climate strategies. The inventories are typically constructed based on landcover information, measured emissions of different plants or vegetation types, and empirical dependencies of the emissions on environmental variables such as temperature and light. This thesis is focused on the VOC emissions from the boreal forest, the largest terrestrial biome with characteristic vegetation patterns and strong seasonality. The isoprene, monoterpene and sesquiterpene emissions of the most prevalent boreal tree species in Finland, Scots pine, have been measured and their seasonal variation and dependence on temperature and light have been studied. The measured emission data and other available observations of the emissions of the principal boreal trees have been used in a biogenic emission model developed for the boreal forests in Finland. The model utilizes satellite landcover information, Finnish forest classification and hourly meteorological data to calculate isoprene, monoterpene, sesquiterpene and other VOC emissions over the growing season. The principal compounds emitted by Scots pine are DELTA3-carene and alpha-pinene in the south boreal zone and alpha- and beta-pinene in the north boreal zone. The monoterpene emissions are dependent on temperature and have a clear seasonal cycle with high emissions in spring

  13. Land Use Change and Recommendation for Sustainable Development of Peatland for Agriculture: Case Study at Kubu Raya and Pontianak Districts, West Kalimantan

    OpenAIRE

    Wahyunto, Wahyunto; Supriatna, Wahyu; Agus, Fahmuddin

    2010-01-01

    Peatland is an increasingly important land resource for livelihood, economic development, and terrestrial carbon storage. Kubu Raya and Pontianak Districts of West Kalimantan rely their future agricultural development on this environmentally fragile peatland because of the dominance (58% and 16% area, respectively) of this land in the two districts. A study aimed to evaluate land use changes on peatland and to develop strategies for sustainable peatland use and management for agriculture. Tim...

  14. Detecting peatland drains with Object Based Image Analysis and Geoeye-1 imagery.

    Science.gov (United States)

    Connolly, J; Holden, N M

    2017-12-01

    Peatlands play an important role in the global carbon cycle. They provide important ecosystem services including carbon sequestration and storage. Drainage disturbs peatland ecosystem services. Mapping drains is difficult and expensive and their spatial extent is, in many cases, unknown. An object based image analysis (OBIA) was performed on a very high resolution satellite image (Geoeye-1) to extract information about drain location and extent on a blanket peatland in Ireland. Two accuracy assessment methods: Error matrix and the completeness, correctness and quality (CCQ) were used to assess the extracted data across the peatland and at several sub sites. The cost of the OBIA method was compared with manual digitisation and field survey. The drain maps were also used to assess the costs relating to blocking drains vs. a business-as-usual scenario and estimating the impact of each on carbon fluxes at the study site. The OBIA method performed well at almost all sites. Almost 500 km of drains were detected within the peatland. In the error matrix method, overall accuracy (OA) of detecting the drains was 94% and the kappa statistic was 0.66. The OA for all sub-areas, except one, was 95-97%. The CCQ was 85%, 85% and 71% respectively. The OBIA method was the most cost effective way to map peatland drains and was at least 55% cheaper than either field survey or manual digitisation, respectively. The extracted drain maps were used constrain the study area CO 2 flux which was 19% smaller than the prescribed Peatland Code value for drained peatlands. The OBIA method used in this study showed that it is possible to accurately extract maps of fine scale peatland drains over large areas in a cost effective manner. The development of methods to map the spatial extent of drains is important as they play a critical role in peatland carbon dynamics. The objective of this study was to extract data on the spatial extent of drains on a blanket bog in the west of Ireland. The

  15. Detecting peatland drains with Object Based Image Analysis and Geoeye-1 imagery

    Directory of Open Access Journals (Sweden)

    J. Connolly

    2017-03-01

    Full Text Available Abstract Background Peatlands play an important role in the global carbon cycle. They provide important ecosystem services including carbon sequestration and storage. Drainage disturbs peatland ecosystem services. Mapping drains is difficult and expensive and their spatial extent is, in many cases, unknown. An object based image analysis (OBIA was performed on a very high resolution satellite image (Geoeye-1 to extract information about drain location and extent on a blanket peatland in Ireland. Two accuracy assessment methods: Error matrix and the completeness, correctness and quality (CCQ were used to assess the extracted data across the peatland and at several sub sites. The cost of the OBIA method was compared with manual digitisation and field survey. The drain maps were also used to assess the costs relating to blocking drains vs. a business-as-usual scenario and estimating the impact of each on carbon fluxes at the study site. Results The OBIA method performed well at almost all sites. Almost 500 km of drains were detected within the peatland. In the error matrix method, overall accuracy (OA of detecting the drains was 94% and the kappa statistic was 0.66. The OA for all sub-areas, except one, was 95–97%. The CCQ was 85%, 85% and 71% respectively. The OBIA method was the most cost effective way to map peatland drains and was at least 55% cheaper than either field survey or manual digitisation, respectively. The extracted drain maps were used constrain the study area CO2 flux which was 19% smaller than the prescribed Peatland Code value for drained peatlands. Conclusions The OBIA method used in this study showed that it is possible to accurately extract maps of fine scale peatland drains over large areas in a cost effective manner. The development of methods to map the spatial extent of drains is important as they play a critical role in peatland carbon dynamics. The objective of this study was to extract data on the spatial extent of

  16. Melatonin: Buffering the Immune System

    Directory of Open Access Journals (Sweden)

    Juan M. Guerrero

    2013-04-01

    Full Text Available Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed.

  17. Melatonin: Buffering the Immune System

    Science.gov (United States)

    Carrillo-Vico, Antonio; Lardone, Patricia J.; Álvarez-Sánchez, Nuria; Rodríguez-Rodríguez, Ana; Guerrero, Juan M.

    2013-01-01

    Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed. PMID:23609496

  18. Modelling of buffer material behaviour

    International Nuclear Information System (INIS)

    Boergesson, L.

    1988-12-01

    Some material models of smectite rich buffer material suited for nuclear waste isolation are accounted for in the report. The application of these models in finite element calculations of some scenarios and performance are also shown. The rock shear scenario has been closely studied with comparisons between calculated and measured results. Sensitivity analyses of the effect of changing the density of the clay and the rate of shear have been performed as well as one calculation using a hollow steel cylinder. Material models and finite element calculations of canister settlement, thermomechanical effects and swelling are also accounted for. The report shows the present state of the work to establish material models and calculation tools which can be used at the final design of the repository. (31 illustrations)

  19. Signature-based store checking buffer

    Science.gov (United States)

    Sridharan, Vilas; Gurumurthi, Sudhanva

    2015-06-02

    A system and method for optimizing redundant output verification, are provided. A hardware-based store fingerprint buffer receives multiple instances of output from multiple instances of computation. The store fingerprint buffer generates a signature from the content included in the multiple instances of output. When a barrier is reached, the store fingerprint buffer uses the signature to verify the content is error-free.

  20. Amine Measurements in Boreal Forest Air

    Science.gov (United States)

    Hemmilä, Marja; Hellén, Heidi; Makkonen, Ulla; Hakola, Hannele

    2015-04-01

    Amines are reactive, volatile bases in the air with a general formula of RNH2, R2NH or R3N. Especially small amines can stabilize sulphuric acid clusters and hence affect nucleation. Amines react rapidly with hydroxyl radical (OH˙) thus affecting oxidative capacity of the atmosphere. The amine concentrations are higher in forest air than in urban air (Hellén et al., 2014), but the sources are not known. In order to get more information concerning amine sources, we conducted a measurement campaign in a boreal forest. At SMEAR II station at Hyytiälä, Southern Finland (61°510'N, 24°170'E, 180 m a.s.l.) The measurements cover seven months, from June to December 2014. For sampling and measuring we used MARGA (The instrument for Measuring AeRosols and Gases in Ambient air) which is an on-line ion chromatograph (IC) connected to a sampling system. The IC component of the MARGA system was coupled to an electrospray ionization quadrupole mass spectrometer (MS) to improve sensitivity of amine measurements. This new set-up enabled amine concentration measurements in ambient air both in aerosol and gas phases with a time resolution of only 1 hour. With MARGA-MS we analysed 7 different amines: monomethylamine (MMA), dimethylamine (DMA), trimethylamine (TMA), ethylamine (EA), diethylamine (DEA), propylamine (PA) and butylamine (BA). In preliminary data-analysis we found out, that in June and July most of the measured amines were in gas phase, and particle phase amine concentrations were mostly under detection limits (<1.7 pptv). In June the gaseous amine concentrations were higher than in July. The measured concentrations of gaseous amines followed temperature variation, which could indicate that amines are produced and emitted from the environment or re-emitted from the surfaces as temperature rises after deposition during night-time. All measured amines had similar diurnal variation with maxima during afternoon and minima during night. Results from other months will also

  1. Methane and carbon dioxide exchange in a post-extraction, unrestored peatland in Eastern Quebec, Canada

    Science.gov (United States)

    Rankin, Tracy; Strachan, Ian; Strack, Maria

    2017-04-01

    Peatlands, in their pristine state, are important long-term sinks of carbon. The extraction of peat for agricultural purposes or for biofuel leads to a shift in the carbon dynamics. Changes in environmental conditions post extraction may also allow for invasive species to establish and spread across the peatland. Many studies have shown the benefits and advantages of various restoration management practices, but few studies have explored the carbon exchange from unrestored peatlands. Our study reports the methane (CH4) and carbon dioxide (CO2) fluxes from a post-extraction, unrestored peatland in Eastern Québec at both the plant community scale using static chambers, and at the ecosystem scale using an eddy covariance flux tower, over two complete years. Extraction of the Saint-Alexandre-de-Kamouraska peatland (SAK) started in the early 1970's and was halted in 1999. No restoration efforts have been implemented and the remnant ditches remain unblocked. The site consists of sparse patches of Eriophorum and a vast area of bare peat. Consequently, SAK is an overall source of carbon to the atmosphere, releasing an annual total of 153 g C m-2 and 241 g C m-2 in CO2 emissions for 2014 and 2015, respectively, and an average annual total of 1 g C m-2yr-1 in CH4 emissions. Phragmites and Typha, both invasive species, have established themselves in the ditches and are sources of methane; partly explaining the increased emissions in carbon fluxes to the atmosphere post extraction. Results from this study will help managers assess the importance of post-extraction peatland restoration, by comparing the differences in CO2 and CH4 exchange between restored and unrestored peatlands.

  2. Summer carbon dioxide and water vapor fluxes across a range of northern peatlands

    Science.gov (United States)

    Humphreys, Elyn R.; Lafleur, Peter M.; Flanagan, Lawrence B.; Hedstrom, Newell; Syed, Kamran H.; Glenn, Aaron J.; Granger, Raoul

    2006-12-01

    Northern peatlands are a diverse group of ecosystems varying along a continuum of hydrological, chemical, and vegetation gradients. These ecosystems contain about one third of the global soil carbon pool, but it is uncertain how carbon and water cycling processes and response to climate change differ among peatland types. This study examines midsummer CO2 and H2O fluxes measured using the eddy covariance technique above seven northern peatlands including a low-shrub bog, two open poor fens, two wooded moderately rich fens, and two open extreme-rich fens. Gross ecosystem production and ecosystem respiration correlated positively with vegetation indices and with each other. Consequently, 24-hour net ecosystem CO2 exchange was similar among most of the sites (an average net carbon sink of 1.5 ± 0.2 g C m-2 d-1) despite large differences in water table depth, water chemistry, and plant communities. Evapotranspiration was primarily radiatively driven at all sites but a decline in surface conductance with increasing water vapor deficit indicated physiological restrictions to transpiration, particularly at the peatlands with woody vegetation and less at the peatlands with 100% Sphagnum cover. Despite these differences, midday evapotranspiration ranged only from 0.21 to 0.34 mm h-1 owing to compensation among the factors controlling evapotranspiration. Water use efficiency varied among sites primarily as a result of differences in productivity and plant functional type. Although peatland classification includes a great variety of ecosystem characteristics, peatland type may not be an effective way to predict the magnitude and characteristics of midsummer CO2 and water vapor exchanges.

  3. SODR Memory Control Buffer Control ASIC

    Science.gov (United States)

    Hodson, Robert F.

    1994-01-01

    The Spacecraft Optical Disk Recorder (SODR) is a state of the art mass storage system for future NASA missions requiring high transmission rates and a large capacity storage system. This report covers the design and development of an SODR memory buffer control applications specific integrated circuit (ASIC). The memory buffer control ASIC has two primary functions: (1) buffering data to prevent loss of data during disk access times, (2) converting data formats from a high performance parallel interface format to a small computer systems interface format. Ten 144 p in, 50 MHz CMOS ASIC's were designed, fabricated and tested to implement the memory buffer control function.

  4. Modelling atmospheric OH-reactivity in a boreal forest ecosystem

    DEFF Research Database (Denmark)

    Mogensen, D.; Smolander, S.; Sogachev, Andrey

    2011-01-01

    We have modelled the total atmospheric OH-reactivity in a boreal forest and investigated the individual contributions from gas phase inorganic species, isoprene, monoterpenes, and methane along with other important VOCs. Daily and seasonal variation in OH-reactivity for the year 2008 was examined...

  5. Global climate change adaptation: examples from Russian boreal forests

    International Nuclear Information System (INIS)

    Krankina, O.N.; Dixon, R.K.; Kirilenko, A.P.; Kobak, K.I.

    1997-01-01

    The Russian Federation contains approximately 20% of the world's timber resources and more than half of all boreal forests. These forests play a prominent role in environmental protection and economic development at global, national, and local levels, as well as, provide commodities for indigenous people and habitat for a variety of plant and animal species. The response and feedbacks of Russian boreal forests to projected global climate change are expected to be profound. Current understanding of the vulnerability of Russian forest resources to projected climate change is discussed and examples of possible adaptation measures for Russian forests are presented including: (1) artificial forestation techniques that can be applied with the advent of failed natural regeneration and to facilitate forest migration northward; (2) silvicultural measures that can influence the species mix to maintain productivity under future climates; (3) identifying forests at risk and developing special management adaption measures for them: (4) alternative processing and uses of wood and non-wood products from future forests; and (5) potential future infrastructure and transport systems that can be employed as boreal forests shift northward into melting permafrost zones. Current infrastructure and technology can be employed to help Russian boreal forests adapt to projected global environmental change, however many current forest management practices may have to be modified. Application of this technical knowledge can help policymakers identify priorities for climate change adaptation

  6. Regional coherency of boreal forest growth defines Arctic driftwood provenancing

    Czech Academy of Sciences Publication Activity Database

    Hellmann, L.; Agafonov, L.; Churakova (Sidorova), O.; Düthorn, E.; Eggertsson, O.; Esper, J.; Kirdyanov, A. V.; Knorre, A. A.; Moiseev, P.; Myglan, V. S.; Nikolaev, A. N.; Reinig, F.; Schweingruber, F.; Solomina, O.; Tegel, W.; Büntgen, Ulf

    2016-01-01

    Roč. 39, sep (2016), s. 3-9 ISSN 1125-7865 Institutional support: RVO:67179843 Keywords : mackenzie river driftwood * tree-ring data * central siberia * origin * archipelago * holocene * ocean * sea * ice * circulation * Driftwood * Arctic * Dendro-provenancing * Boreal Subject RIV: EF - Botanics Impact factor: 2.259, year: 2016

  7. Resilience of Alaska's Boreal Forest to Climatic Change

    Science.gov (United States)

    Chapin, F. S., III; McGuire, A. D.; Ruess, R. W.; Hollingsworth, T. N.; Mack, M. C.; Johnstone, J. F.; Kasischke, E. S.; Euskirchen, E. S.; Jones, J. B.; Jorgenson, M. T.; hide

    2010-01-01

    This paper assesses the resilience of Alaska s boreal forest system to rapid climatic change. Recent warming is associated with reduced growth of dominant tree species, plant disease and insect outbreaks, warming and thawing of permafrost, drying of lakes, increased wildfire extent, increased postfire recruitment of deciduous trees, and reduced safety of hunters traveling on river ice. These changes have modified key structural features, feedbacks, and interactions in the boreal forest, including reduced effects of upland permafrost on regional hydrology, expansion of boreal forest into tundra, and amplification of climate warming because of reduced albedo (shorter winter season) and carbon release from wildfires. Other temperature-sensitive processes for which no trends have been detected include composition of plant and microbial communities, long-term landscape-scale change in carbon stocks, stream discharge, mammalian population dynamics, and river access and subsistence opportunities for rural indigenous communities. Projections of continued warming suggest that Alaska s boreal forest will undergo significant functional and structural changes within the next few decades that are unprecedented in the last 6000 years. The impact of these social ecological changes will depend in part on the extent of landscape reorganization between uplands and lowlands and on policies regulating subsistence opportunities for rural communities.

  8. Modeling Alaska boreal forests with a controlled trend surface approach

    Science.gov (United States)

    Mo Zhou; Jingjing Liang

    2012-01-01

    An approach of Controlled Trend Surface was proposed to simultaneously take into consideration large-scale spatial trends and nonspatial effects. A geospatial model of the Alaska boreal forest was developed from 446 permanent sample plots, which addressed large-scale spatial trends in recruitment, diameter growth, and mortality. The model was tested on two sets of...

  9. Boreal forests and atmosphere - Biosphere exchange of carbon dioxide

    Science.gov (United States)

    D'Arrigo, Rosanne; Jacoby, Gordon C.; Fung, Inez Y.

    1987-01-01

    Two approaches to investigating the role of boreal forests in the global carbon cycle are presented. First, a tracer support model which incorporates the normalized-difference vegetation index obtained from advanced, very high resolution radiometer radiances was used to simulate the annual cycle of CO2 in the atmosphere. Results indicate that the seasonal growth of the combined boreal forests of North America and Eurasia accounts for about 50 percent of the mean seasonal CO2 amplitude recorded at Pt. Barrow, Alaska and about 30 percent of the more globally representative CO2 signal at Mauna Loa, Hawaii. Second, tree-ring width data from four boreal treeline sites in northern Canada were positively correlated with Pt. Barrow CO2 drawdown for the period 1971-1982. These results suggest that large-scale changes in the growth of boreal forests may be contributing to the observed increasing trend in CO2 amplitude. They further suggest that tree-ring data may be applicable as indices for CO2 uptake and remote sensing estimates of photosynthetic activity.

  10. Mosaic boreal landscapes with open and forested wetlands

    International Nuclear Information System (INIS)

    Sjoeberg, K.; Ericson, L.

    1997-01-01

    We review patterns and processes important for biodiversity in the Fennoscandian boreal forest, describe man's past and present impact and outline a strategy for conservation. The boreal landscape was earlier characterized by a mosaic of open and forested wetlands and forests. Drainage and felling operation have largely changed that pattern. Several organisms depend upon the landscape mosaic. Natural ecotones between mire and forest provide food resources predictable in space and time contrasting to unpredictable edges in the silvicultured landscape. The mosaic is also a prerequisite for organisms dependent on non-substitutable resources in the landscape. The importance of swamp forests has increased as they function as refugia for earlier more widespread old-growth species. Programmes for maintaining biodiversity in the boreal landscape should include the following points. First, the natural mosaic with open and forested wetlands must be maintained. Second, swamp forests must receive a general protection as they often constitute the only old-growth patches in the landscape. Third, we need to restore earlier disturbance regimes. Present strategy plans for conservation are insufficient, as they imply that a too large proportion of boreal organisms will not be able to survive outside protected areas. Instead, we need to focus more on how to preserve organisms in the man-influenced landscape. As a first step we need to understand how organisms are distributed in landscapes at various spatial scales. We need studies in landscapes where the original mosaic has faced various degrees of fragmentation. (au) 124 refs

  11. Resilience of Alaska’s boreal forest to climatic change

    Science.gov (United States)

    Chapin, F.S.; McGuire, A. David; Ruess, Roger W.; Hollingsworth, Teresa N.; Mack, M.C.; Johnstone, J.F.; Kasischke, E.S.; Euskirchen, E.S.; Jones, J.B.; Jorgenson, M.T.; Kielland, K.; Kofinas, G.; Turetsky, M.R.; Yarie, J.; Lloyd, A.H.; Taylor, D.L.

    2010-01-01

    This paper assesses the resilience of Alaska’s boreal forest system to rapid climatic change. Recent warming is associated with reduced growth of dominant tree species, plant disease and insect outbreaks, warming and thawing of permafrost, drying of lakes, increased wildfire extent, increased postfire recruitment of deciduous trees, and reduced safety of hunters traveling on river ice. These changes have modified key structural features, feedbacks, and interactions in the boreal forest, including reduced effects of upland permafrost on regional hydrology, expansion of boreal forest into tundra, and amplification of climate warming because of reduced albedo (shorter winter season) and carbon release from wildfires. Other temperature-sensitive processes for which no trends have been detected include composition of plant and microbial communities, long-term landscape-scale change in carbon stocks, stream discharge, mammalian population dynamics, and river access and subsistence opportunities for rural indigenous communities. Projections of continued warming suggest that Alaska’s boreal forest will undergo significant functional and structural changes within the next few decades that are unprecedented in the last 6000 years. The impact of these social–ecological changes will depend in part on the extent of landscape reorganization between uplands and lowlands and on policies regulating subsistence opportunities for rural communities.

  12. Moss-nitrogen input to boreal forest soils

    DEFF Research Database (Denmark)

    Rousk, Kathrin; Jones, Davey; DeLuca, Thomas

    2014-01-01

    Cyanobacteria living epiphytically on mosses in pristine, unpolluted areas fix substantial amounts of atmospheric nitrogen (N) and therefore represent a primary source of N in N-limited boreal forests. However, the fate of this N is unclear, in particular, how the fixed N2 enters the soil and bec...... and that transfer of N to the soil is not facilitated by fungal hyphae....

  13. Factors limiting the recovery of boreal toads (Bufo b. boreas)

    Science.gov (United States)

    Carey, C.; Corn, P.S.; Jones, M.S.; Livo, L.J.; Muths, E.; Loeffler, C.W.; Lannoo, M.

    2005-01-01

    Boreal toads (Bufo b. boreas) are widely distributed over much of the mountainous western United States. Populations in the Southern Rocky Mountains suffered extensive declines in the late 1970s through early 1980s (Carey, 1993). At the time, these mass mortalities were thought to be associated with a bacterial infection (Carey, 1993). Although the few populations that survived the mass die-offs were not systematically monitored until at least 1993, no mass mortalities had been observed until 1996 when die-offs were observed. A mycotic skin infection associated with a chytrid fungus is now causing mortality of toads in at least two of the populations (M.S. Jones and D.E. Green, unpublished data; Muths et al., 2003). Boreal toads are now absent throughout large areas of their former distribution in Colorado and southern Wyoming and may be extinct in New Mexico (Corn et al., 1989; Carey, 1993; Stuart and Painter, 1994). These toads are classified as “endangered” by Colorado and New Mexico and are designated as a protected non-game species in Wyoming. The U.S. Fish and Wildlife Service has categorized the Southern Rocky Mountain populations for federal listing and is currently reviewing their designation as a “warranted but precluded” species for possible listing in the next few years. For the management of boreal toads and their habitats, a Boreal Toad Recovery Team was formed by the Colorado Division of Wildlife in 1995 as part of a collaborative effort with federal agencies within the United States’ departments of the Interior and Agriculture and with agencies in two adjoining states. To date, conservation agreements have been signed by eight state and federal agencies and by the Colorado Natural Heritage Program. Although boreal toads were considered common throughout their range in Colorado, no comprehensive surveys of the numbers and sizes of their populations were conducted prior to mass die-offs in the 1970s. Surveys completed in the late 1980s to

  14. Carbon pools and productivity in a 1-km2 heterogeneous forest and peatland mosaic in Minnesota, USA

    Science.gov (United States)

    Peter Weishampel; Randall Kolka; Jennifer Y. King

    2009-01-01

    Determining the magnitude of carbon (C) storage in forests and peatlands is an important step towards predicting how regional carbon balance will respond to climate change. However, spatial heterogeneity of dominant forest and peatland cover types can inhibit accurate C storage estimates. We evaluated ecosystem C pools and productivity in the Marcell Experimental...

  15. Experimentally increased nutrient availability at the permafrost thaw front selectively enhances biomass production of deep-rooting subarctic peatland species

    NARCIS (Netherlands)

    Keuper, Frida; Dorrepaal, Ellen; van Bodegom, Peter M.; van Logtestijn, Richard; Venhuizen, Gemma; van Hal, Jurgen; Aerts, Rien

    2017-01-01

    Climate warming increases nitrogen (N) mineralization in superficial soil layers (the dominant rooting zone) of subarctic peatlands. Thawing and subsequent mineralization of permafrost increases plant-available N around the thaw-front. Because plant production in these peatlands is N-limited, such

  16. Temperature buffer test. Dismantling operation

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias [Clay Technology AB, Lund (Sweden)

    2010-12-15

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite in the usual way, whereas the upper heater was surrounded by a ring of sand. The test was dismantled and sampled during a period from the end of October 2009 to the end of April 2010, and this report describes this operation. Different types of samples have been obtained during this operation. A large number of diameter 50 mm bentonite cores have been taken for analysis of water content and density. Large pieces, so-called big sectors, have been taken for hydro-mechanical and chemical characterizations. Finally, there has been an interest to obtain different types of interface samples in which bentonite were in contact with sand, iron or concrete. One goal has been to investigate the retrievability of the upper heater, given the possibility to remove the surrounding sand shield, and a retrieval test has therefore been performed. The sand in the shield was first removed with an industrial vacuum cleaner after loosening the material through mechanical means (with hammer drill and core machine). A front loader was subsequently used for applying a sufficient lifting force to release the heater from the bentonite underneath. The experiment has been documented in different aspects: measurements of the coordinate (height or radius) of different interfaces (between bentonite blocks and between bentonite and sand); verification of sensor positions and retrieval of sensors for subsequent

  17. Temperature buffer test. Dismantling operation

    International Nuclear Information System (INIS)

    Aakesson, Mattias

    2010-12-01

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite in the usual way, whereas the upper heater was surrounded by a ring of sand. The test was dismantled and sampled during a period from the end of October 2009 to the end of April 2010, and this report describes this operation. Different types of samples have been obtained during this operation. A large number of diameter 50 mm bentonite cores have been taken for analysis of water content and density. Large pieces, so-called big sectors, have been taken for hydro-mechanical and chemical characterizations. Finally, there has been an interest to obtain different types of interface samples in which bentonite were in contact with sand, iron or concrete. One goal has been to investigate the retrievability of the upper heater, given the possibility to remove the surrounding sand shield, and a retrieval test has therefore been performed. The sand in the shield was first removed with an industrial vacuum cleaner after loosening the material through mechanical means (with hammer drill and core machine). A front loader was subsequently used for applying a sufficient lifting force to release the heater from the bentonite underneath. The experiment has been documented in different aspects: measurements of the coordinate (height or radius) of different interfaces (between bentonite blocks and between bentonite and sand); verification of sensor positions and retrieval of sensors for subsequent

  18. Environmental dynamics and carbon accumulation rate of a tropical peatland in Central Sumatra, Indonesia

    Science.gov (United States)

    Hapsari, Kartika Anggi; Biagioni, Siria; Jennerjahn, Tim C.; Reimer, Peter Meyer; Saad, Asmadi; Achnopha, Yudhi; Sabiham, Supiandi; Behling, Hermann

    2017-08-01

    Tropical peatlands are important for the global carbon cycle as they store 18% of the total global peat carbon. As they are vulnerable to changes in temperature and precipitation, a rapidly changing environment endangers peatlands and their carbon storage potential. Understanding the mechanisms of peatland carbon accumulation from studying past developments may, therefore, help to assess the future role of tropical peatlands. Using a multi-proxy palaeoecological approach, a peat core taken from the Sungai Buluh peatland in Central Sumatra has been analyzed for its pollen and spore, macro charcoal and biogeochemical composition. The result suggests that peat and C accumulation rates were driven mainly by sea level change, river water level, climatic variability and anthropogenic activities. It is also suggested that peat C accumulation in Sungai Buluh is correlated to the abundance of Freycinetia, Myrtaceae, Calophyllum, Stemonuraceae, Ficus and Euphorbiaceae. Sungai Buluh has reasonable potential for being a future global tropical peat C sinks. However, considering the impact of rapid global climate change in addition to land-use change following rapid economic growth in Indonesia, such potential may be lost. Taking advantage of available palaeoecological records and advances made in Quaternary studies, some considerations for management practice such as identification of priority taxa and conservation sites are suggested.

  19. The long-term fate of permafrost peatlands under rapid climate warming

    Science.gov (United States)

    Swindles, Graeme T.; Morris, Paul J.; Mullan, Donal; Watson, Elizabeth J.; Turner, T. Edward; Roland, Thomas P.; Amesbury, Matthew J.; Kokfelt, Ulla; Schoning, Kristian; Pratte, Steve; Gallego-Sala, Angela; Charman, Dan J.; Sanderson, Nicole; Garneau, Michelle; Carrivick, Jonathan L.; Woulds, Clare; Holden, Joseph; Parry, Lauren; Galloway, Jennifer M.

    2015-01-01

    Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed in response to climatic warming, culminating in collapse of the peat domes. Commonalities between study sites lead us to propose a five-phase model for permafrost peatland response to climatic warming. This model suggests a shared ecohydrological trajectory towards a common end point: inundated Arctic fen. Although carbon accumulation is rapid in such sites, saturated soil conditions are likely to cause elevated methane emissions that have implications for climate-feedback mechanisms. PMID:26647837

  20. Contrasting controls on arsenic and lead budgets for a degraded peatland catchment in Northern England

    International Nuclear Information System (INIS)

    Rothwell, James J.; Taylor, Kevin G.; Evans, Martin G.; Allott, Timothy E.H.

    2011-01-01

    Atmospheric deposition of trace metals and metalloids from anthropogenic sources has led to the contamination of many European peatlands. To assess the fate and behaviour of previously deposited arsenic and lead, we constructed catchment-scale mass budgets for a degraded peatland in Northern England. Our results show a large net export of both lead and arsenic via runoff (282 ± 21.3 gPb ha -1 y -1 and 60.4 ± 10.5 gAs ha -1 y -1 ), but contrasting controls on this release. Suspended particulates account for the majority of lead export, whereas the aqueous phase dominates arsenic export. Lead release is driven by geomorphological processes and is a primary effect of erosion. Arsenic release is driven by the formation of a redox-dynamic zone in the peat associated with water table drawdown, a secondary effect of gully erosion. Degradation of peatland environments by natural and anthropogenic processes has the potential to release the accumulated pool of legacy contaminants to surface waters. - Highlights: → The fluvial outputs of arsenic and lead in the degraded peatland are an order-of-magnitude greater than atmospheric inputs. → The particulate phase dominates fluvial lead export, whereas the aqueous phase dominates fluvial arsenic export. → Lead export is a primary effect of peat erosion, whereas arsenic export is a secondary effect of peat erosion. - Degraded peatlands can be significant sources of previously deposited arsenic and lead

  1. Representing Northern Peatland Hydrology and Biogeochemistry with ALM Land Surface Model

    Science.gov (United States)

    Shi, X.; Ricciuto, D. M.; Thornton, P. E.; Hanson, P. J.; Xu, X.; Mao, J.; Warren, J.; Yuan, F.; Norby, R. J.; Sebestyen, S.; Griffiths, N.; Weston, D. J.; Walker, A.

    2017-12-01

    Northern peatlands are likely to be important in future carbon cycle-climate feedbacks due to their large carbon pool and vulnerability to hydrological change. Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth for a vegetated wetland, independent of prescribed regional water tables. Firstly, we introduce a new configuration of the land model (ALM) of Accelerated Climate model for Energy (ACME), which includes a fully prognostic water table calculation for a vegetated peatland. Secondly, we couple our new hydrology treatment with vertically structured soil organic matter pool, and the addition of components from methane biogeochemistry. Thirdly, we introduce a new PFT for mosses and implement the water content dynamics and physiology of mosses. We inform and test our model based on SPRUCE experiment to get the reasonable results for the seasonal dynamics water table depths, water content dynamics and physiology of mosses, and correct soil carbon profiles. Then, we use our new model structure to test the how the water table depth and CH4 emission will respond to elevated CO2 and different warming scenarios.

  2. Differences in microbial community structure and nitrogen cycling in natural and drained tropical peatland soils.

    Science.gov (United States)

    Espenberg, Mikk; Truu, Marika; Mander, Ülo; Kasak, Kuno; Nõlvak, Hiie; Ligi, Teele; Oopkaup, Kristjan; Maddison, Martin; Truu, Jaak

    2018-03-16

    Tropical peatlands, which play a crucial role in the maintenance of different ecosystem services, are increasingly drained for agriculture, forestry, peat extraction and human settlement purposes. The present study investigated the differences between natural and drained sites of a tropical peatland in the community structure of soil bacteria and archaea and their potential to perform nitrogen transformation processes. The results indicate significant dissimilarities in the structure of soil bacterial and archaeal communities as well as nirK, nirS, nosZ, nifH and archaeal amoA gene-possessing microbial communities. The reduced denitrification and N 2 -fixing potential was detected in the drained tropical peatland soil. In undisturbed peatland soil, the N 2 O emission was primarily related to nirS-type denitrifiers and dissimilatory nitrate reduction to ammonium, while the conversion of N 2 O to N 2 was controlled by microbes possessing nosZ clade I genes. The denitrifying microbial community of the drained site differed significantly from the natural site community. The main reducers of N 2 O were microbes harbouring nosZ clade II genes in the drained site. Additionally, the importance of DNRA process as one of the controlling mechanisms of N 2 O fluxes in the natural peatlands of the tropics revealed from the results of the study.

  3. Scale-dependent spatial variability in peatland lead pollution in the southern Pennines, UK

    International Nuclear Information System (INIS)

    Rothwell, James J.; Evans, Martin G.; Lindsay, John B.; Allott, Timothy E.H.

    2007-01-01

    Increasingly, within-site and regional comparisons of peatland lead pollution have been undertaken using the inventory approach. The peatlands of the Peak District, southern Pennines, UK, have received significant atmospheric inputs of lead over the last few hundred years. A multi-core study at three peatland sites in the Peak District demonstrates significant within-site spatial variability in industrial lead pollution. Stochastic simulations reveal that 15 peat cores are required to calculate reliable lead inventories at the within-site and within-region scale for this highly polluted area of the southern Pennines. Within-site variability in lead pollution is dominant at the within-region scale. The study demonstrates that significant errors may be associated with peatland lead inventories at sites where only a single peat core has been used to calculate an inventory. Meaningful comparisons of lead inventories at the regional or global scale can only be made if the within-site variability of lead pollution has been quantified reliably. - Multiple peat cores are required for accurate peatland Pb inventories

  4. Manure derived biochar can successfully replace phosphate rock amendment in peatland restoration.

    Science.gov (United States)

    Pouliot, Rémy; Hugron, Sandrine; Rochefort, Line; Godbout, Stéphane; Palacios, Joahnn H; Groeneveld, Elisabeth; Jarry, Isabelle

    2015-07-01

    Phosphate rock fertilization is commonly used in peatland restoration to promote the growth of Polytrichum strictum, a nurse plant which aids the establishment of Sphagnum mosses. The present study tested whether 1) phosphorus fertilization facilitates the germination of P. strictum spores and 2) biochar derived from local pig manure can replace imported phosphate rock currently used in peatland restoration. Various doses of biochar were compared to phosphate rock to test its effect directly on P. strictum stem regeneration (in Petri dishes in a growth chamber) and in a simulation of peatland restoration with the moss layer transfer technique (in mesocoms in a greenhouse). Phosphorus fertilization promoted the germination of P. strictum spores as well as vegetative stem development. Biochar can effectively replace phosphate rock in peatland restoration giving a new waste management option for rural regions with phosphorus surpluses. As more available phosphorus was present in biochar, an addition of only 3-9 g m(-2) of pig manure biochar is recommended during the peatland restoration process, which is less than the standard dose of phosphate rock (15 g m(-2)). Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Sphagnum peatland development at their southern climatic range in West Siberia: trends and peat accumulation patterns

    International Nuclear Information System (INIS)

    Peregon, Anna; Uchida, Masao; Shibata, Yasuyuki

    2007-01-01

    A region of western Siberia is vulnerable to the predicted climatic change which may induce an important modification to the carbon balance in wetland ecosystems. This study focuses on the evaluation of both the long-term and contemporary trends of peat (carbon) accumulation and its patterns at the southern climatic range of Sphagnum peatlands in western Siberia. Visible and physical features of peat and detailed reconstructions of successional change (or sediment stratigraphies) were analysed at two types of forest-peatland ecotones, which are situated close to each other but differ by topography and composition of their plant communities. Our results suggest that Siberian peatlands exhibit a general trend towards being a carbon sink rather than a source even at or near the southern limit of their distribution. Furthermore, two types of peat accumulation were detected in the study area, namely persistent and intermittent. As opposed to persistent peat accumulation, the intermittent one is characterized by the recurrent degradation of the upper peat layers at the marginal parts of raised bogs. Persistent peat accumulation is the case for the majority of Sphagnum peatlands under current climatic conditions. It might be assumed that more peat will accumulate under the 'increased precipitation' scenarios of global warming, although intermittent peat accumulation could result in the eventual drying that may change peatlands from carbon sinks to carbon sources

  6. Peatland water repellency: Importance of soil water content, moss species, and burn severity

    Science.gov (United States)

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

    2017-11-01

    Wildfire is the largest disturbance affecting peatlands, with northern peat reserves expected to become more vulnerable to wildfire as climate change enhances the length and severity of the fire season. Recent research suggests that high water table positions after wildfire are critical to limit atmospheric carbon losses and enable the re-establishment of keystone peatland mosses (i.e. Sphagnum). Post-fire recovery of the moss surface in Sphagnum-feathermoss peatlands, however, has been shown to be limited where moss type and burn severity interact to result in a water repellent surface. While in situ measurements of moss water repellency in peatlands have been shown to be greater for feathermoss in both a burned and unburned state in comparison to Sphagnum moss, it is difficult to separate the effect of water content from species. Consequently, we carried out a laboratory based drying experiment where we compared the water repellency of two dominant peatland moss species, Sphagnum and feathermoss, for several burn severity classes including unburned samples. The results suggest that water repellency in moss is primarily controlled by water content, where a sharp threshold exists at gravimetric water contents (GWC) lower than ∼1.4 g g-1. While GWC is shown to be a strong predictor of water repellency, the effect is enhanced by burning. Based on soil water retention curves, we suggest that it is highly unlikely that Sphagnum will exhibit strong hydrophobic conditions under field conditions.

  7. Towards large-scale paludiculture: addressing the challenges of biomass harvesting in wet and rewetted peatlands

    Directory of Open Access Journals (Sweden)

    C. Schröder

    2015-12-01

    Full Text Available Peatland drainage causes peat degradation, which results in high greenhouse gas emissions and ongoing subsidence of the ground surface. To avoid further land degradation, the rewetting of peatlands is essential. The new land use concept of paludiculture - the use of wet and rewetted peatlands for agriculture and forestry - now offers possibilities for landowners and land managers to continue using these sites under wet conditions. But new challenges arise due to the limited bearing capacity of wet soils, which restricts accessibility for machinery. Whilst many site-specific technical solutions for harvesting on wet peatland are available, it remains unclear whether current machinery is suitable for use in the large-scale implementation of paludiculture. Repeated crossings of the same ground can easily disturb the upper peat layer and cause serious problems for the removal of biomass. In this article we present available machinery and approaches to biomass harvesting; and explore how the number of transport runs required for biomass removal varies with productivity of the site, cargo capacity and working width of the harvesting machinery. The results are used in a discussion of logistics and infrastructure requirements to facilitate the implementation of paludiculture. Whilst there is still considerable scope for improvement of harvesting technologies, our results show that a peat-conserving harvest from wet and rewetted peatlands is possible with adjustments to harvesting technique, logistics and site infrastructure.

  8. Moss and peat hydraulic properties are optimized to maximise peatland water use efficiency

    Science.gov (United States)

    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.

  9. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Buffered penicillin powder, penicillin powder with... FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered aqueous diluent. (a) Specifications. When reconstituted, each milliliter contains penicillin G procaine equivalent...

  10. Paludiculture as a chance for peatland and climate: the greenhouse gas balance of biomass production on two rewetted peatlands does not differ from the natural state

    Science.gov (United States)

    Günther, Anke; Huth, Vytas; Jurasinski, Gerald; Albrecht, Kerstin; Glatzel, Stephan

    2015-04-01

    In Europe, rising prices for farm land make it increasingly difficult for government administrations to compete with external investors during the acquisition of land for wetland conservation. Thus, adding economic value to these, otherwise "lost", areas by combining extensive land use with nature conservation efforts could increase the amount of ground available for wetland restoration. Against this background, the concept of paludiculture aims to provide biomass for multiple purposes from peatlands with water tables high enough to conserve the peat body. However, as plants have been shown to contribute to greenhouse gas exchange in peatlands, manipulating the vegetation (by harvesting, sowing etc.) might alter the effect of the restored peatlands on climate. Here, we present greenhouse gas data from two experimental paludiculture systems on formerly drained intensive grasslands in northern Germany. In a fen that has been rewetted more than 15 years ago three species of reed plants were harvested to simulate biomass production for bioenergy and as construction material. And in a peat bog that has been converted from drained grassland to a field with a controlled water table around ground surface Sphagnum mosses were cultivated to provide an alternative growing substrate for horticulture. In both systems, we determined carbon dioxide, methane, and nitrous oxide exchange using closed chambers over two years. Additionally, water and peat chemistry and environmental parameters as recorded by a weather station were analyzed. Both restored peatlands show greenhouse gas balances comparable to those of natural ecosystems. Nitrous oxide was not emitted in either system. Fluctuations of the emissions reflect changes in weather conditions across the study years. In the fen, relative emission patterns between plant species were not constant over time. We did not find a negative short-term effect of biomass harvest or Sphagnum cultivation on net greenhouse gas balances

  11. Geoecological controls on net mercury retention in northern peatlands

    Science.gov (United States)

    Bindler, R.; Rydberg, J.

    2010-12-01

    Peatlands, which receive much or all of their element inputs (e.g. nutrients or trace metals) via the atmosphere, are considered an ideal archive for studying past changes in mercury (Hg) deposition. These archives potentially contain information not only on important anthropogenic contributions to the environment over the past few centuries, but also on the natural antecedent conditions over the past several millennia. However, the assumption that Hg accumulation rates in peat represent an absolute record of past atmospheric deposition has proved problematic. In on-going studies of Hg retention in northern peatlands (bogs and oligotrophic fens) we find that net Hg accumulation is influenced by a range of geoecological factors in addition to actual changes in atmospheric deposition. Factors that influence the interception and net retention of Hg include differences in vegetation and microtopography - both of which may enhance dry deposition, and properties and processes within the peat such as decomposition that might influence long-term retention. Wetness, too, may play an important role in net retention in the surface peat through increased evasive losses of Hg. Differences between Hg concentrations in vascular plants and mosses are well established (at our site: 5-15 ng/g for leaves/needles of cottongrass, heather, Labrador tea and pine; 15-45 ng/g for mosses Sphagnum centrale and S. rubellum), but we also measured significant differences between different mosses within the same plots (S. rubellum, 24±3 ng/g; S. centrale, 18±2 ng/g). Further differences in Hg concentrations occur for single moss species in different settings; for example, Hg concentrations in S. centrale in open Sphagnum-only plots relative to plots including a mixture of vascular plants that form a field-layer canopy are 18±2 and 32±6 ng/g, respectively. As a result, sampling sites consisting of both Sphagnum and vascular plants have long-term cumulative inventories of mercury in the peat

  12. THE BUFFER CAPACITY OF AIRWAY EPITHELIAL SECRETIONS

    Directory of Open Access Journals (Sweden)

    Dusik eKim

    2014-06-01

    Full Text Available The pH of airway epithelial secretions influences bacterial killing and mucus properties and is reduced by acidic pollutants, gastric reflux, and respiratory diseases such as cystic fibrosis (CF. The effect of acute acid loads depends on buffer capacity, however the buffering of airway secretions has not been well characterized. In this work we develop a method for titrating micro-scale (30 µl volumes and use it to study fluid secreted by the human airway epithelial cell line Calu-3, a widely used model for submucosal gland serous cells. Microtitration curves revealed that HCO3- is the major buffer. Peak buffer capacity (β increased from 17 to 28 mM/pH during forskolin stimulation, and was reduced by >50% in fluid secreted by cystic fibrosis transmembrane conductance regulator (CFTR-deficient Calu-3 monolayers, confirming an important role of CFTR in HCO3- secretion. Back-titration with NaOH revealed non-volatile buffer capacity due to proteins synthesized and released by the epithelial cells. Lysozyme and mucin concentrations were too low to buffer Calu-3 fluid significantly, however model titrations of porcine gastric mucins at concentrations near the sol-gel transition suggest that mucins may contribute to the buffer capacity of ASL in vivo. We conclude that CFTR-dependent HCO3- secretion and epithelially-derived proteins are the predominant buffers in Calu-3 secretions.

  13. Shock buffer for nuclear control assembly

    International Nuclear Information System (INIS)

    Bevilacqua, F.

    1977-01-01

    A shock buffer is provided for the gradual deceleration of a rapidly descending control element assembly in a nuclear reactor. The interactive buffer components are associated respectively with the movable control element assembly and part of the upper guide structure independent of and spaced from the fuel assemblies of the reactor

  14. Preliminary Assessment of JERS-1 SAR to Discriminating Boreal Landscape Features for the Boreal Forest Mapping Project

    Science.gov (United States)

    McDonald, Kyle; Williams, Cynthia; Podest, Erika; Chapman, Bruce

    1999-01-01

    This paper presents an overview of the JERS-1 North American Boreal Forest Mapping Project and a preliminary assessment of JERS-1 SAR imagery for application to discriminating features applicable to boreal landscape processes. The present focus of the JERS-1 North American Boreal Forest Mapping Project is the production of continental scale wintertime and summertime SAR mosaics of the North American boreal forest for distribution to the science community. As part of this effort, JERS-1 imagery has been collected over much of Alaska and Canada during the 1997-98 winter and 1998 summer seasons. To complete the mosaics, these data will be augmented with data collected during previous years. These data will be made available to the scientific community via CD ROM containing these and similar data sets compiled from companion studies of Asia and Europe. Regional landscape classification with SAR is important for the baseline information it will provide about distribution of woodlands, positions of treeline, current forest biomass, distribution of wetlands, and extent of major rivercourses. As well as setting the stage for longer term change detection, comparisons across several years provides additional baseline information about short-term landscape change. Rapid changes, including those driven by fire, permafrost heat balance, flooding, and insect outbreaks can dominate boreal systems. We examine JERS-1 imagery covering selected sites in Alaska and Canada to assess quality and applicability to such relevant ecological and hydrological issues. The data are generally of high quality and illustrate many potential applications. A texture-based classification scheme is applied to selected regions to assess the applicability of these data for distinguishing distribution of such landcover types as wetland, tundra, woodland and forested landscapes.

  15. Buffer sizing for multi-hop networks

    KAUST Repository

    Shihada, Basem

    2014-01-28

    A cumulative buffer may be defined for an interference domain in a wireless mesh network and distributed among nodes in the network to maintain or improve capacity utilization of network resources in the interference domain without increasing packet queuing delay times. When an interference domain having communications links sharing resources in a network is identified, a cumulative buffer size is calculated. The cumulative buffer may be distributed among buffers in each node of the interference domain according to a simple division or according to a cost function taking into account a distance of the communications link from the source and destination. The network may be monitored and the cumulative buffer size recalculated and redistributed when the network conditions change.

  16. Optimization of protein buffer cocktails using Thermofluor.

    Science.gov (United States)

    Reinhard, Linda; Mayerhofer, Hubert; Geerlof, Arie; Mueller-Dieckmann, Jochen; Weiss, Manfred S

    2013-02-01

    The stability and homogeneity of a protein sample is strongly influenced by the composition of the buffer that the protein is in. A quick and easy approach to identify a buffer composition which increases the stability and possibly the conformational homogeneity of a protein sample is the fluorescence-based thermal-shift assay (Thermofluor). Here, a novel 96-condition screen for Thermofluor experiments is presented which consists of buffer and additive parts. The buffer screen comprises 23 different buffers and the additive screen includes small-molecule additives such as salts and nucleotide analogues. The utilization of small-molecule components which increase the thermal stability of a protein sample frequently results in a protein preparation of higher quality and quantity and ultimately also increases the chances of the protein crystallizing.

  17. Permafrost Thaw increases Emissions of Nitrous Oxide from Subarctic Peatlands

    Science.gov (United States)

    Voigt, C.; Marushchak, M. E.; Lamprecht, R. E.; Jackowicz-Korczynski, M.; Lindgren, A.; Mastepanov, M.; Christensen, T. R.; Granlund, L.; Tahvanainen, T.; Martikainen, P. J.; Biasi, C.

    2017-12-01

    Permafrost soils in the Arctic are thawing, exposing not only carbon but also large nitrogen stocks. The decomposition of this vast pool of long-term immobile C and N stocks results in the release of greenhouse gases to the atmosphere. Among these, carbon dioxide (CO2) and methane (CH4) are being studied extensively, and gaseous C release from thawing permafrost is known to be substantial. Most recent studies, however, show that Arctic soils may further be a relevant source of the strong greenhouse gas nitrous oxide (N2O). As N2O is almost 300 times more powerful in warming the climate than CO2 based on a 100-yr time horizon, the release of N2O from thawing permafrost could create a significant non-carbon permafrost-climate feedback. To study the effect of permafrost thaw on N2O fluxes, we collected peat mesocosms from a Subarctic permafrost peatland, and subjected these intact soil-plant systems to sequential thawing from the top of the active layer down to the upper permafrost layer. Measurements of N2O fluxes were coupled with detailed soil analyses and process studies. Since N2O fluxes are highly dependent on moisture conditions and vegetation cover, we applied two distinct moisture treatments (dry vs. wet) and simulated permafrost thaw in vegetated as well as in naturally bare mesocosms. Under dry conditions, permafrost thaw clearly increased N2O emissions. We observed the largest post-thaw emissions from bare peat surfaces, a typical landform in subarctic peatlands previously identified as hot spots for Arctic N2O emissions. There, permafrost thaw caused a five-fold increase in emissions (0.56 vs. 2.81 mg N2O m-2 d-1). While water-logged conditions suppressed N2O emissions, the presence of vegetation lowered, but did not prevent post-thaw N2O release. Based on these findings, we show that one fourth of the Arctic land area could be vulnerable for N2O emissions when permafrost thaws. Our results demonstrate that Arctic N2O emissions may be larger than

  18. Land cover distribution in the peatlands of Peninsular Malaysia, Sumatra and Borneo in 2015 with changes since 1990

    Directory of Open Access Journals (Sweden)

    Jukka Miettinen

    2016-04-01

    Full Text Available Insular Southeast Asian peatlands have experienced rapid land cover changes over the past decades inducing a variety of environmental effects ranging from regional consequences on peatland ecology, biodiversity and hydrology to globally significant carbon emissions. In this paper we present the land cover and industrial plantation distribution in the peatlands of Peninsular Malaysia, Sumatra and Borneo in 2015 and analyse their changes since 1990. We create the 2015 maps by visual interpretation of 30 m resolution Landsat data and combine them with fully comparable and completed land cover maps of 1990 and 2007 (Miettinen and Liew, 2010. Our results reveal continued peatland deforestation and conversion into managed land cover types. In 2015, 29% (4.6 Mha of the peatlands in the study area remain covered by peat swamp forest (vs. 41% or 6.4 Mha in 2007 and 76% or 11.9 Mha in 1990. Managed land cover types (industrial plantations and small-holder dominated areas cover 50% (7.8 Mha of all peatlands (vs. 33% 5.2 Mha in 2007 and 11% 1.7 Mha in 1990. Industrial plantations have nearly doubled their extent since 2007 (2.3 Mha; 15% and cover 4.3 Mha (27% of peatlands in 2015. The majority of these are oil palm plantations (73%; 3.1 Mha while nearly all of the rest (26%; 1.1 Mha are pulp wood plantations. We hope that the maps presented in this paper will enable improved evaluation of the magnitude of various regional to global level environmental effects of peatland conversion and that they will help decision makers to define sustainable peatland management policies for insular Southeast Asian peatlands.

  19. COMBINATIONS OF BUFFER-STOCKS AND BUFFER-FUNDS FOR WOOL PRICE STABILISATION IN AUSTRALIA

    OpenAIRE

    Moir, Brian; Piggott, Roley R.

    1991-01-01

    In this paper a preliminary analysis is presented of a combined buffer-fund and buffer-stock as an alternative to a pure buffer-fund or a pure buffer stock for stabilising wool prices. The alternatives analysed are designed so that each provides the same prices to producers as did the Reserve Price Scheme over the period of analysis. Least-cost combinations of policy instruments are derived. The results show that there is considerable potential for cost savings to be made by combining buffer-...

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

    Science.gov (United States)

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

    2015-02-01

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

  1. Buffer mass test - Site documentation

    International Nuclear Information System (INIS)

    Pusch, R.

    1983-10-01

    The purpose of this report is to compile test site data that are assumed to be of importance for the interpretation of the Buffer Mass Test. Since this test mainly concerns water uptake and migration processes in the integrated rock/backfill system and the development of temperature fields in this system, the work has been focused on the constitution and hydrology of the rock. The major constitutional rock feature of interest for the BMT is the frequency and distribution of joints and fractures. The development of models for water uptake into the highly compacted bentonite in the heater holes requires a very detailed fracture survey. The present investigation shows that two of the holes (no. 1 and 2) are located in richly fractured rock, while the others are located in fracture-poor to moderately fractured rock. The hydrological conditions of the rock in the BMT area are characterized by water pressures of as much as 100 m water head at a few meters distance from the test site. The average hydraulic conductivity of the rock that confines the BMT tunnel has been estimated at about 10 -10 m/s by Lawrence Laboratory. The actual distribution of the water that enters the tunnel has been estimated by observing the successive moistening after having switched off the ventilation, and this has offered basis of predicting the rate and uniformity of the water uptake in the tunnel backfill. As to the heater holes the detailed fracture patterns and various inflow measurements have yielded a similar basis. The report also gives major data on the rock temperature, gas conditions, mineralogy, rock mechanics, and groundwater chemistry for BMT purposes. (author)

  2. Temperature buffer test. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias [Clay Technology AB, Lund (Sweden)

    2012-04-15

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report is the final report and a summary of all work performed within the TBT project. The design and the installation of the different components are summarized: the depositions hole, the heating system, the bentonite blocks with emphasis on the initial density and water content in these, the filling of slots with sand or pellets, the retaining construction with the plug, lid and nine anchor cables, the artificial saturation system, and finally the instrumentation. An overview of the operational conditions is presented: the power output from heaters, which was 1,500 W (and also 1,600 W) from each heater during the first {approx}1,700 days, and then changed to 1,000 and 2,000 W, for the upper and lower heater respectively, during the last {approx}600 days. From the start, the bentonite was hydrated with a groundwater from a nearby bore-hole, but this groundwater was replaced with de-ionized water from day {approx}1,500, due to the high flow resistance of the injections points in the filter, which implied that a high filter pressure couldn't be sustained. The sand shield around the upper heater was hydrated from day {approx}1,500 to day {approx}1

  3. Temperature buffer test. Final report

    International Nuclear Information System (INIS)

    Aakesson, Mattias

    2012-04-01

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report is the final report and a summary of all work performed within the TBT project. The design and the installation of the different components are summarized: the depositions hole, the heating system, the bentonite blocks with emphasis on the initial density and water content in these, the filling of slots with sand or pellets, the retaining construction with the plug, lid and nine anchor cables, the artificial saturation system, and finally the instrumentation. An overview of the operational conditions is presented: the power output from heaters, which was 1,500 W (and also 1,600 W) from each heater during the first ∼1,700 days, and then changed to 1,000 and 2,000 W, for the upper and lower heater respectively, during the last ∼600 days. From the start, the bentonite was hydrated with a groundwater from a nearby bore-hole, but this groundwater was replaced with de-ionized water from day ∼1,500, due to the high flow resistance of the injections points in the filter, which implied that a high filter pressure couldn't be sustained. The sand shield around the upper heater was hydrated from day ∼1,500 to day ∼1,800. The sensors data concerning

  4. An impact of deforestation by extreme weather events on Sphagnum peatland ecosystem

    Science.gov (United States)

    Slowinski, M. M.; Łuców, D.; Kołaczek, P.; Tjallingii, R.; Lane, C. S.; Slowinska, S.; Tyszkowski, S.; Łokas, E.; Theuerkauf, M.; Brauer, A.; Lamentowicz, M.

    2017-12-01

    An increase in extreme weather phenomena has been observed over the last decades as a result of global climate warming. Terrestrial ecosystems are influenced by different types of disturbances such as e.g. deforestation, land-use, fragmentation, fire, floods or storms. Disturbance triggers may be natural or anthropogenic, but usually we observe negative feedback loops and interconnected causal factors. Here we investigate the effects of a tornado event on the peatland ecosystem of the Tuchola Pinewoods, Northern Poland. Deforestation by tornado events can cause severe perturbations of the hydrology and erosion that, in turn, affects adjacent lakes and peatlands. Martwe peatland provide an exceptional opportunity to study the impact of such extreme events, as it was struck by a tornado in 2012. Our research is focused on lake-peatland ecosystems that were directly affected by this tornado, and we consider the general transformation of the vegetation (mainly forests) over the last 150 years. Extensive clearing of the forest occurred in the nineteenth century due to human activity, and we compare this with the impact of the 2012 tornado. Accurate reconstructions will rely on a broad range of palaeoecological techniques such as pollen, macro-remains and testate amoebae, but also on geochemistry, i.e. μXRF scanning. The chronology of the records is based on 210Pb and radiocarbon dating and will incorporate correlations using (crypto)tephra markers of the Eyjafjöll (2010) and Askja (1875) eruptions. We expect to observe that disturbance (tornado-induced deforestation) affects the short-term changes in peatland productivity and biodiversity, through a cascading "top-down" effect. This research addresses the emerging issue of the impact of extreme phenomena and more general climate changes on peatland ecosystems, which will potentially help to inform adaptations to the environmental consequences of extreme events in the future. This project is funded by the Polish

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

    Science.gov (United States)

    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.

  6. Ecohydrological dynamics of peatlands and adjacent upland forests in the Rocky Mountains

    Science.gov (United States)

    Millar, D.; Parsekian, A.; Mercer, J.; Ewers, B. E.; Mackay, D. S.; Williams, D. G.; Cooper, D. J.; Ronayne, M. J.

    2017-12-01

    Mountain peatlands are susceptible to a changing climate via changes in the water cycle. Understanding the impacts of such changes requires knowledge of the hydrological processes within these peatlands and in the upland forests that supply them with water. We investigated hydrological processes in peatland catchments in the Rocky Mountains by developing empirical models of groundwater dynamics, and are working to improve subsurface water dynamics in a ecohydrological process model, the Terrestrial Regional Ecosystem Exchange Simulator (TREES). Results from empirical models showed major differences in water budget components between two peatlands with differing climate, vegetation, and hydrogeological settings. Several-fold higher rates of evapotranspiration from the saturated zone, and groundwater inflow were observed for a sloping fen in southern Wyoming than that of a basin fen in southwestern Colorado, where rainfall was two-fold higher due to stronger influence of the North American monsoon. We also present ongoing work coupling stable water isotope and borehole nuclear magnetic resonance analyses to test which soil water pools (bound or mobile) are used by dominant upland and peatland vegetation in two catchments in southern Wyoming. These data are being used to test whether the root hydraulic mechanisms in TREES can simulate water uptake from these two soil water pools, and sap flux measurements are being used to evaluate simulated transpiration. Preliminary results from this work suggest that upland vegetation utilize tightly-bound soil water pools, as these pools comprise the largest amount of subsurface water (> 80%) in the vadose zone long after snow melt. Conversely, it appears that herbaceous peatland hydrophytes may preferentially utilize mobile soil water pools, since their roots extend below the water table. The results of this work are expected to increase predictive understanding of hydrological processes in these important ecosystems.

  7. Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export.

    Science.gov (United States)

    Olefeldt, David; Roulet, Nigel T

    2014-10-01

    Permafrost thaw in peatlands has the potential to alter catchment export of dissolved organic carbon (DOC) and thus influence downstream aquatic C cycling. Subarctic peatlands are often mosaics of different peatland types, where permafrost conditions regulate the hydrological setting of each type. We show that hydrological setting is key to observed differences in magnitude, timing, and chemical composition of DOC export between permafrost and nonpermafrost peatland types, and that these differences influence the export of DOC of larger catchments even when peatlands are minor catchment components. In many aspects, DOC export from a studied peatland permafrost plateau was similar to that of a forested upland catchment. Similarities included low annual export (2-3 g C m(-2) ) dominated by the snow melt period (~70%), and how substantial DOC export following storms required wet antecedent conditions. Conversely, nonpermafrost fens had higher DOC export (7 g C m(-2) ), resulting from sustained hydrological connectivity during summer. Chemical composition of catchment DOC export arose from the mixing of highly aromatic DOC from organic soils from permafrost plateau soil water and upland forest surface horizons with nonaromatic DOC from mineral soil groundwater, but was further modulated by fens. Increasing aromaticity from fen inflow to outlet was substantial and depended on both water residence time and water temperature. The role of fens as catchment biogeochemical hotspots was further emphasized by their capacity for sulfate retention. As a result of fen characteristics, a 4% fen cover in a mixed catchment was responsible for 34% higher DOC export, 50% higher DOC concentrations and ~10% higher DOC aromaticity at the catchment outlet during summer compared to a nonpeatland upland catchment. Expansion of fens due to thaw thus has potential to influence landscape C cycling by increasing fen capacity to act as biogeochemical hotspots, amplifying aquatic C cycling, and

  8. Effects of peatland drainage management on peak flows

    Directory of Open Access Journals (Sweden)

    C. E. Ballard

    2012-07-01

    Full Text Available Open ditch drainage has historically been a common land management practice in upland blanket peats, particularly in the UK. However, peatland drainage is now generally considered to have adverse effects on the upland environment, including increased peak flows. As a result, drain blocking has become a common management strategy in the UK over recent years, although there is only anecdotal evidence to suggest that this might decrease peak flows. The change in the hydrological regime associated with the drainage of blanket peat and the subsequent blocking of drains is poorly understood, therefore a new physics-based model has been developed that allows the exploration of the associated hydrological processes. A series of simulations is used to explore the response of intact, drained and blocked drain sites at field scales. While drainage is generally found to increase peak flows, the effect of drain blocking appears to be dependent on local conditions, sometimes decreasing and sometimes increasing peak flows. Based on insights from these simulations we identify steep smooth drains as those that would experience the greatest reduction in field-scale peak flows if blocked and recommend that future targeted field studies should be focused on examining surface runoff characteristics.

  9. Reservoirs as hotspots of fluvial carbon cycling in peatland catchments.

    Science.gov (United States)

    Stimson, A G; Allott, T E H; Boult, S; Evans, M G

    2017-02-15

    Inland water bodies are recognised as dynamic sites of carbon processing, and lakes and reservoirs draining peatland soils are particularly important, due to the potential for high carbon inputs combined with long water residence times. A carbon budget is presented here for a water supply reservoir (catchment area~9km 2 ) draining an area of heavily eroded upland peat in the South Pennines, UK. It encompasses a two year dataset and quantifies reservoir dissolved organic carbon (DOC), particulate organic carbon (POC) and aqueous carbon dioxide (CO 2 (aq)) inputs and outputs. The budget shows the reservoir to be a hotspot of fluvial carbon cycling, as with high levels of POC influx it acts as a net sink of fluvial carbon and has the potential for significant gaseous carbon export. The reservoir alternates between acting as a producer and consumer of DOC (a pattern linked to rainfall and temperature) which provides evidence for transformations between different carbon species. In particular, the budget data accompanied by 14 C (radiocarbon) analyses provide evidence that POC-DOC transformations are a key process, occurring at rates which could represent at least ~10% of the fluvial carbon sink. To enable informed catchment management further research is needed to produce carbon cycle models more applicable to these environments, and on the implications of high POC levels for DOC composition. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Atmospheric fallout radionuclides in peatland from Southern Poland.

    Science.gov (United States)

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

    2017-09-01

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

  11. Peatlands and green frogs: A relationship regulated by acidity?

    Science.gov (United States)

    Mazerolle, M.J.

    2005-01-01

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

  12. Peatland fertilization. Short-term chemical effects on runoff water

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    In peatland forestry, fertilization is often needed to reach a good yield. Phosphorus and potassium are mainly used, but on nutrient poor fens and bogs, nitrogen also has be added. These fertilizers affect the environment and thereby influence the runoff waters. This essay concerns the first three months after fertilization, of which the first two weeks have been paid particular attention. As the mires of the sub-basins were sedge fens, with a pine stand in some areas but mostly treeless, the fertilizers used were ammonium nitrate , rock phosphate and potassium chloride . The fertilization was performed from the air. During the very first hours after fertilization, drastic changes in water chemistry were found. In one area pH dropped 0,3 units while at the other no immidiate change was seen. For the whole three months of the investigation period, the decreases in pH were in the range 0,1-0,5 units. Nitrogen concentration reached a peak of 260 mg/l, phosphorus 5 mg/l and potassium about 60 mg/l. These high values were of short duration but the concentrations were considerable increased during one week. Later, partly due to decreasing discharge, the water chemistry became almost similar to that measured under unfertilized conditions. The main loss of fertilizer occurred during the first two weeks and amounted to 22% of the applied nitrogen, about 1% of the phosphorus and 5-9% of K.

  13. Dynamic mechanical properties of buffer material

    International Nuclear Information System (INIS)

    Takaji, Kazuhiko; Taniguchi, Wataru

    1999-11-01

    The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (i) it has exceptionally low water permeability and properties to control the movement of water in buffer, (ii) it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (iii) it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of dynamic triaxial tests, measurement of elastic wave velocity and liquefaction tests that aim at getting hold of dynamic mechanical properties. We can get hold of dependency on the shearing strain of the shearing modulus and hysteresis damping constant, the application for the mechanical model etc. by dynamic triaxial tests, the acceptability of maximum shearing modulus obtained from dynamic triaxial tests etc. by measurement of elastic wave velocity and dynamic strength caused by cyclic stress etc. by liquefaction tests. (author)

  14. Buffer-regulated biocorrosion of pure magnesium.

    Science.gov (United States)

    Kirkland, Nicholas T; Waterman, Jay; Birbilis, Nick; Dias, George; Woodfield, Tim B F; Hartshorn, Richard M; Staiger, Mark P

    2012-02-01

    Magnesium (Mg) alloys are being actively investigated as potential load-bearing orthopaedic implant materials due to their biodegradability in vivo. With Mg biomaterials at an early stage in their development, the screening of alloy compositions for their biodegradation rate, and hence biocompatibility, is reliant on cost-effective in vitro methods. The use of a buffer to control pH during in vitro biodegradation is recognised as critically important as this seeks to mimic pH control as it occurs naturally in vivo. The two different types of in vitro buffer system available are based on either (i) zwitterionic organic compounds or (ii) carbonate buffers within a partial-CO(2) atmosphere. This study investigated the influence of the buffering system itself on the in vitro corrosion of Mg. It was found that the less realistic zwitterion-based buffer did not form the same corrosion layers as the carbonate buffer, and was potentially affecting the behaviour of the hydrated oxide layer that forms on Mg in all aqueous environments. Consequently it was recommended that Mg in vitro experiments use the more biorealistic carbonate buffering system when possible.

  15. Peatlands in Finland accumulate carbon more than the peat production and utilization liberates it

    International Nuclear Information System (INIS)

    Maentymaa, E.

    1997-01-01

    The peatlands in Finland bind more carbon dioxide then it is liberated into the air in peat combustion and production. Because the carbon accumulation into peatlands is higher than that of liberation, the peat deposits increase all the time in spite of peat economy. The emissions of methane, which is tens of times worse greenhouse gas then CO 2 , have decreased by 40 % due to forest drainage. Very small amounts of methane is released into the atmosphere from peat production sites. This is proven by the national SILMU research programme investigating the atmospheric changes

  16. Carbon isotopic composition of deep carbon gases in an ombrogenous peatland, northwestern Ontario, Canada

    International Nuclear Information System (INIS)

    Aravena, R.; Dinel, H.

    1993-01-01

    Radiocarbon dating and carbon isotope analyses of deep peat and gases in a small ombrogenous peatland in northwestern Ontario reveals the presence of old gases at depth that are 1000-2000 yr younger than the enclosing peat. The authors suggest that the most likely explanation to account for this age discrepancy is the downward movement by advection of younger dissolved organic carbon for use by fermentation and methanogens bacteria. This study identifies a potentially large supply of old carbon gases in peatlands that should be considered in global carbon models of the terrestrial biosphere

  17. Headwater peatland channels in south-eastern Australia; the attainment of equilibrium

    Science.gov (United States)

    Nanson, R. A.; Cohen, T. J.

    2014-05-01

    Many small headwater catchments (bank strengths have resulted in low width to depth ratios which accommodate rapid changes in flow velocity and depth with changes in discharge. In small peatland channels, planform adjustments have been sufficient to counter the energy provided by these hydraulically efficient cross-sections and have enabled the achievement of regime energy-slopes. In larger and higher energy peatland channels, large, armoured, stable, bedforms have developed. These bedforms integrate with planform adjustments to maintain a condition of minimum variance in energy losses as represented by the slope profiles and, therefore, a uniform increase in downstream entropy.

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

    Science.gov (United States)

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

    2015-12-01

    Use of large databases of peat cores to examine linkages between northern peatlands and atmospheric CH4 over the Holocene has been prone to uncertainties regarding 1. comparability of radiocarbon techniques and material dated, 2. appropriate summed probability distributions, 3. spatial representativeness of the sites, particularly in capturing sites south of the subarctic, 4. potential impacts of local lateral peatland expansion versus continental-scale peatland initiation, particularly in the late Holocene, and 5. impacts of changes in the proportion of high methane-producing fens vs Sphagnum bogs. We present a comparison of radiocarbon measurements from conventional counts, atomic mass spectrometry and differing peat materials to demonstrate a general compatibility of the various types of dates. We compare and apply several summed probability distribution methods to minimize any statistical bias in our analysis. We then present our analysis of a new data set of 7571 peatland cores from 4420 sites that extend into the temperate zone. Of these, 3732 cores inform on lateral expansion and 329 dates constrain the timing of fen-bog transition. Based on these data in original and gridded form we show that widespread peat initiation commenced at 16 kcal yr BP and reached a maximum rate at 11-8 kcal yr BP. Most sites began as fens, and peak transition to bogs occurred between 5 and 3 kcal yr BP, with a 1000 year lag between Eurasia and North America. There is no global late Holocene increase in lateral expansion. Based on modeled northern peatland area and ratio of fen/bog sites, CH4 production from northern peatlands increased rapidly from 11 to 9 cal yr BP, followed by slower increase until reaching a maximum at 5 kcal yr BP at 25 Tg per yr. From 4 kcal yr BP to Present, bogs become a dominant feature in the northern peatland landscape and CH4 production decreased to reach modern-day levels at about 20 Tg per yr. Northern peatlands have been a key infleunce on global

  19. Aquatic carbon export from peatland catchments recently undergone wind farm development

    Science.gov (United States)

    Smith, Ben; Waldron, Susan; Henderson, Andrew; Flowers, Hugh; Gilvear, David

    2013-04-01

    Scotland's peat landscapes are desirable locations for wind-based renewables due to high wind resources and low land use pressures in these areas. The environmental impact of sitting wind-based renewables on peats however, is unknown. Globally, peatlands are important terrestrial carbon stores. Given the topical nature of carbon-related issues, e.g. global warming and carbon footprints, it is imperative we help mitigate their degradation and maintain carbon sequestration. To do so, we need to better understand how peatland systems function with regards to their carbon balance (export versus sequestration) so we can assess their resilience and adaptation to hosting land-based renewable energy projects. Predicting carbon lost as a result of construction of wind farms built on peatland has not been fully characterised and this research will provide data that can supplement current 'carbon payback calculator' models for wind farms that aim to reinforce their 'green' credentials. Transfer of carbon from the terrestrial peatland systems to the aquatic freshwater and oceanic systems is most predominant during periods of high rainfall. It has been estimated that 50% of carbon is exported during only 10% of highest river flows, (Hinton et al., 1998). Furthermore, carbon export from peatlands is known to have a seasonal aspect with highest concentrations of dissolved organic carbon (DOC) found mostly in late summer months of August and September and lowest in December and January, (Dawson et al., 2004). Event sampling, where high intensity sample collection is carried out during high river flow periods, offers a better insight, understanding and estimation of carbon aquatic fluxes from peatland landscapes. The Gordonbush estate, near Brora, has an extensive peatland area where a wind farm development has recently been completed (April 2012). Investigations of aquatic carbon fluxes from this peatland system were started in July 2010, in conjunction with the start of

  20. Carbon emissions from Southeast Asian peatlands will increase despite emission-reduction schemes.

    Science.gov (United States)

    Wijedasa, Lahiru S; Sloan, Sean; Page, Susan E; Clements, Gopalasamy R; Lupascu, Massimo; Evans, Theodore A

    2018-06-01

    Carbon emissions from drained peatlands converted to agriculture in Southeast Asia (i.e. Peninsular Malaysia, Sumatra and Borneo) are globally significant and increasing. Here, we map the growth of Southeast Asian peatland agriculture and estimate CO 2 emissions due to peat drainage in relation to official land-use plans with a focus on the Reducing Emissions from Deforestation and Degradation (REDD+) related Indonesian moratorium on granting new concession licenses for industrial agriculture and logging. We find that, prior to 2010, 35% of Southeast Asian peatlands had been converted to agriculture, principally by smallholder farmers (15% of original peat extent) and industrial oil palm plantations (14%). These conversions resulted in 1.46-6.43 GtCO 2 of emissions between 1990 and 2010. This legacy of historical clearances on deep peat areas will contribute 51% (4.43-11.45 GtCO 2 ) of projected peatland CO 2 emissions over the period 2010-2130. In Indonesia, which hosts most of the region's peatland and where concession maps are publicly available, 70% of peatland conversion to agriculture occurred outside of known concessions for industrial plantation development, with smallholders accounting for 60% and industrial oil palm accounting for 34%. Of the remaining Indonesian peatswamp forest (PSF), 45% is not protected, and its conversion would amount to CO 2 emissions equivalent to 0.7-2.3% (5.14-14.93 Gt) of global fossil fuel and cement emissions released between 1990-2010. Of the peatland extent included in the moratorium, 48% was no longer forested, and of the PSF included 40-48% is likely to be affected by drainage impacts from agricultural areas and will emit CO 2 over time. We suggest that recent legislation and policy in Indonesia could provide a means of meaningful emission reductions if focused on revised land-use planning, PSF conservation both inside and outside agricultural concessions, and the development of agricultural practices based on

  1. Forest fires may cause cooling in boreal Canada

    Science.gov (United States)

    Bhattacharya, Atreyee

    2012-08-01

    As climate in North America continues to become warmer and drier through the 21st century, a new study finds that fire may be playing an increasingly important role in shaping the climate of the boreal regions of Canada. Forest fires change the amount of shortwave radiation absorbed by Earth's surface by reducing vegetation cover and changing the composition of plant species, thereby changing the reflectivity of the surface (albedo). Fires also affect other ecosystem processes and increase aerosol (particularly soot) emission and deposition, all of which alter regional climate through a series of feedbacks mechanisms. Jin et al. used satellite observations of surface albedo from 2000 to 2011 and fire perimeter data since 1970 to study how forest fires affect surface albedo and associated shortwave radiation at the surface, across forests in boreal Canada.

  2. The role of fire in the boreal carbon budget

    Science.gov (United States)

    Harden, J.W.; Trumbore, S.E.; Stocks, B.J.; Hirsch, A.; Gower, S.T.; O'Neill, K. P.; Kasischke, E.S.

    2000-01-01

    To reconcile observations of decomposition rates, carbon inventories, and net primary production (NPP), we estimated long-term averages for C exchange in boreal forests near Thompson, Manitoba. Soil drainage as defined by water table, moss cover, and permafrost dynamics, is the dominant control on direct fire emissions. In upland forests, an average of about 10-30% of annual NPP was likely consumed by fire over the past 6500 years since these landforms and ecosystems were established. This long-term, average fire emission is much larger than has been accounted for in global C cycle models and may forecast an increase in fire activity for this region. While over decadal to century times these boreal forests may be acting as slight net sinks for C from the atmosphere to land, periods of drought and severe fire activity may result in net sources of C from these systems.

  3. Buffer protection in the installation phase

    International Nuclear Information System (INIS)

    Wimelius, Hans; Pusch, Roland

    2008-12-01

    The research and development of the design and construction of the SKB's repository for final disposal of spent reactor fuel is conducted along several paths ('lines'). Issues concerning the bedrock are dealt with in the 'rock line' and those related to buffer and backfill in deposition holes and tunnels are considered in the 'buffer line' and 'backfill line', respectively. These lines also deal with sub-activities that are coupled to several other lines. One of them includes development of techniques for protecting buffer blocks from moisture and water in the installation phase. Techniques and methods for placement and removal of the 'buffer protection sheet' are dealt with in the 'buffer line'. The removal is, however, considered as being part of the backfilling sequence. Since the performance of the sheet is of fundamental importance to the placement and function of the buffer it deserves particular attention. Thus, the removal of the rubber sheet that serves to protect the buffer blocks in the installation phase may be difficult and can cause significant problems that may require retrieval of already placed canister, buffer and backfill. These matters are in focus in the present report. Arrangements for protecting already placed buffer blocks from moist air and water have been tested in earlier large-scale experiments, i.e. the Prototype Repository project at Aespoe but the experience from them has called for more effective protection of the clay blocks as described in the present report. Focus is on the construction of foundation components at the bottom of the deposition holes required for establishing a tight seal between rock and buffer blocks, and on the protection sheet and arrangements for limiting water pressure on it. Special attention is paid to the drainage of the space between rock and protection sheet that is necessary for avoiding failure of the sheet and to systems for achieving this and for providing alarm signals if the allowed pressure is

  4. Buffer protection in the installation phase

    Energy Technology Data Exchange (ETDEWEB)

    Wimelius, Hans (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Pusch, Roland (Geodevelopment International AB, Lund (Sweden))

    2008-12-15

    The research and development of the design and construction of the SKB's repository for final disposal of spent reactor fuel is conducted along several paths ('lines'). Issues concerning the bedrock are dealt with in the 'rock line' and those related to buffer and backfill in deposition holes and tunnels are considered in the 'buffer line' and 'backfill line', respectively. These lines also deal with sub-activities that are coupled to several other lines. One of them includes development of techniques for protecting buffer blocks from moisture and water in the installation phase. Techniques and methods for placement and removal of the 'buffer protection sheet' are dealt with in the 'buffer line'. The removal is, however, considered as being part of the backfilling sequence. Since the performance of the sheet is of fundamental importance to the placement and function of the buffer it deserves particular attention. Thus, the removal of the rubber sheet that serves to protect the buffer blocks in the installation phase may be difficult and can cause significant problems that may require retrieval of already placed canister, buffer and backfill. These matters are in focus in the present report. Arrangements for protecting already placed buffer blocks from moist air and water have been tested in earlier large-scale experiments, i.e. the Prototype Repository project at Aespoe but the experience from them has called for more effective protection of the clay blocks as described in the present report. Focus is on the construction of foundation components at the bottom of the deposition holes required for establishing a tight seal between rock and buffer blocks, and on the protection sheet and arrangements for limiting water pressure on it. Special attention is paid to the drainage of the space between rock and protection sheet that is necessary for avoiding failure of the sheet and to systems for achieving

  5. Surface Water Protection by Productive Buffers

    DEFF Research Database (Denmark)

    Christen, Benjamin

    Vegetated riparian buffer zones are a widely recommended best management practice in agriculture for protecting surface and coastal waters from diffuse nutrient pollution. On the background of the EU funded research project NitroEurope (NEU; www.NitroEurope.eu), this study concentrates...... on the mitigation of nitrogen pollution in surface and groundwater, using riparian buffer zones for biomass production. The objectives are to map suitable areas for buffer implementation across the six NEU study landscapes, model tentative N-loss mitigation, calculate biomass production potential and economic...... designed for local conditions could be a way of protecting water quality attractive to many stakeholders....

  6. Effects of flow regulation and fragmentation by dams on riparian flora in boreal rivers

    International Nuclear Information System (INIS)

    Jansson, Roland

    2000-01-01

    The object of this thesis is to evaluate the effects of river regulation on riparian flora in boreal rivers, and to increase the understanding of the processes causing patterns in species diversity. Comparisons of free-flowing and regulated rivers showed that regulated rivers have fewer plant species and less plant cover per 200-m-stretch of river margin. Regulated river-margins were less species-rich compared to free-flowing rivers irrespective of the type of regulated water level regime, except for unimpounded reaches downstream of dams. Species with good dispersal capacity (wind-dispersed or long-floating species) were least affected by regulation, showing that the ability to recolonize after local extinction is an important character. The temporal development of river-margin vegetation in regulated rivers was studied by investigating differently-old reservoirs and impoundments. Plant-species richness along storage reservoirs increased during the first 30-40 years following damming, but declined thereafter. Both species richness and plant cover remained impoverished compared to free-flowing rivers about 70 years after regulation. Along run-of-river impoundments, plant species richness and cover peaked after 10-20 years. In the long run, riparian species richness was lower, but riparian species density did not differ, compared to free-flowing rivers. Dams fragment the riparian flora. Adjacent run-of-river impoundments developed different riparian floras, probably because dams are barriers to the dispersal of species with poor floating ability. This shows that dams disrupt the ecological continuity not only for the river channel, but also for the adjoining riparian corridor. The number of species and genera were similar between river margins along boreal free-flowing rivers in Europe and North America. The riparian floras shared few species but many genera and families. The regional species pools were similar-sized and composed of species with similar traits, and

  7. Growth Decline Linked to Warming-Induced Water Limitation in Hemi-Boreal Forests

    OpenAIRE

    Wu, Xiuchen; Liu, Hongyan; Guo, Dali; Anenkhonov, Oleg A.; Badmaeva, Natalya K.; Sandanov, Denis V.

    2012-01-01

    Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal fore...

  8. Climate-Induced Boreal Forest Change: Predictions versus Current Observations

    Science.gov (United States)

    Soja, Amber J.; Tchebakova, Nadezda M.; French, Nancy H. F.; Flannigan, Michael D.; Shugart, Herman H.; Stocks, Brian J.; Sukhinin, Anatoly I.; Parfenova, E. I.; Chapin, F. Stuart, III; Stackhouse, Paul W., Jr.

    2007-01-01

    For about three decades, there have been many predictions of the potential ecological response in boreal regions to the currently warmer conditions. In essence, a widespread, naturally occurring experiment has been conducted over time. In this paper, we describe previously modeled predictions of ecological change in boreal Alaska, Canada and Russia, and then we investigate potential evidence of current climate-induced change. For instance, ecological models have suggested that warming will induce the northern and upslope migration of the treeline and an alteration in the current mosaic structure of boreal forests. We present evidence of the migration of keystone ecosystems in the upland and lowland treeline of mountainous regions across southern Siberia. Ecological models have also predicted a moisture-stress-related dieback in white spruce trees in Alaska, and current investigations show that as temperatures increase, white spruce tree growth is declining. Additionally, it was suggested that increases in infestation and wildfire disturbance would be catalysts that precipitate the alteration of the current mosaic forest composition. In Siberia, five of the last seven years have resulted in extreme fire seasons, and extreme fire years have also been more frequent in both Alaska and Canada. In addition, Alaska has experienced extreme and geographically expansive multi-year outbreaks of the spruce beetle, which had been previously limited by the cold, moist environment. We suggest that there is substantial evidence throughout the circumboreal region to conclude that the biosphere within the boreal terrestrial environment has already responded to the transient effects of climate change. Additionally, temperature increases and warming-induced change are progressing faster than had been predicted in some regions, suggesting a potential non-linear rapid response to changes in climate, as opposed to the predicted slow linear response to climate change.

  9. Recreation and tourism induced changes in northern boreal environments

    OpenAIRE

    Kangas, K. (Katja)

    2009-01-01

    Abstract The popularity of nature-based tourism has increased worldwide and peripheral areas with conservational value, like protected areas, are attractive destinations. The recreational use and construction of tourism facilities can cause environmental degradation and decrease the conservational and recreational value of areas if not well planned and managed. The aim of this thesis was to improve our knowledge of recreation and tourism induced changes in northern boreal environments. Dir...

  10. Ecosystem Responses to Partial Harvesting in Eastern Boreal Mixedwood Stands

    Directory of Open Access Journals (Sweden)

    Brian D. Harvey

    2013-05-01

    Full Text Available Partial harvesting has been proposed as a key aspect to implementing ecosystem management in the Canadian boreal forest. We report on a replicated experiment located in boreal mixedwoods of Northwestern Quebec. In the winter of 2000–2001, two partial harvesting treatments, one using a dispersed pattern, and a second, which created a (400 m2 gap pattern, were applied to a 90-year-old aspen-dominated mixed stand. The design also included a clear cut and a control. Over the course of the following eight years, live tree, coarse woody debris, regeneration and ground beetles were inventoried at variable intervals. Our results indicate that all harvesting treatments created conditions favorable to balsam fir (Abies balsamea sapling growth and trembling aspen (Populus tremuloides sapling recruitment. However, balsam fir and trembling aspen regeneration and ground beetles response to gap cuts were closer to patterns observed in clear cuts than in dispersed harvesting. The underlying reasons for these differing patterns can be linked to factors associated with the contrasting light regimes created by the two partial harvesting treatments. The study confirms that partially harvesting is an ecologically sound approach in boreal mixedwoods and could contribute to maintaining the distribution of stand ages at the landscape level.

  11. Predicting Climate Change Impacts to the Canadian Boreal Forest

    Directory of Open Access Journals (Sweden)

    Trisalyn A. Nelson

    2014-03-01

    Full Text Available Climate change is expected to alter temperature, precipitation, and seasonality with potentially acute impacts on Canada’s boreal. In this research we predicted future spatial distributions of biodiversity in Canada’s boreal for 2020, 2050, and 2080 using indirect indicators derived from remote sensing and based on vegetation productivity. Vegetation productivity indices, representing annual amounts and variability of greenness, have been shown to relate to tree and wildlife richness in Canada’s boreal. Relationships between historical satellite-derived productivity and climate data were applied to modelled scenarios of future climate to predict and map potential future vegetation productivity for 592 regions across Canada. Results indicated that the pattern of vegetation productivity will become more homogenous, particularly west of Hudson Bay. We expect climate change to impact biodiversity along north/south gradients and by 2080 vegetation distributions will be dominated by processes of seasonality in the north and a combination of cumulative greenness and minimum cover in the south. The Hudson Plains, which host the world’s largest and most contiguous wetland, are predicted to experience less seasonality and more greenness. The spatial distribution of predicted trends in vegetation productivity was emphasized over absolute values, in order to support regional biodiversity assessments and conservation planning.

  12. Carbon storage and long-term rate of accumulation in high-altitude Andean peatlands of Bolivia

    Directory of Open Access Journals (Sweden)

    J.A. Hribljan

    2015-11-01

    Full Text Available (1 The high-altitude (4,500+ m Andean mountain range of north-western Bolivia contains many peatlands. Despite heavy grazing pressure and potential damage from climate change, little is known about these peatlands. Our objective was to quantify carbon pools, basal ages and long-term peat accumulation rates in peatlands in two areas of the arid puna ecoregion of Bolivia: near the village of Manasaya in the Sajama National Park (Cordillera Occidentale, and in the Tuni Condoriri National Park (Cordillera Real. (2 We cored to 5 m depth in the Manasaya peatland, whose age at 5 m was ca. 3,675 yr. BP with a LARCA of 47 g m-2 yr-1. However, probing indicated that the maximum depth was 7–10 m with a total estimated (by extrapolation carbon stock of 1,040 Mg ha-1. The Tuni peat body was 5.5 m thick and initiated ca. 2,560 cal. yr. BP. The peatland carbon stock was 572 Mg ha-1 with a long-term rate of carbon accumulation (LARCA of 37 g m-2 yr-1. (3 Despite the dry environment of the Bolivian puna, the region contains numerous peatlands with high carbon stocks and rapid carbon accumulation rates. These peatlands are heavily used for llama and alpaca grazing.

  13. Buffer sizing for multi-hop networks

    KAUST Repository

    Shihada, Basem; Jamshaid, Kamran

    2014-01-01

    domain according to a simple division or according to a cost function taking into account a distance of the communications link from the source and destination. The network may be monitored and the cumulative buffer size recalculated and redistributed

  14. Moisture Buffer Value of Building Materials

    DEFF Research Database (Denmark)

    Rode, Carsten; Peuhkuri, Ruut; Time, Berit

    2007-01-01

    When building materials are in contact with indoor air they have some effect to moderate the variations of indoor humidity in occupied buildings. But so far there has been a lack of a standardized quantity to characterize the moisture buffering capability of materials. It has been the objective o...... is a test protocol which expresses how materials should be tested for determination of their Moisture Buffer Value. Finally, the paper presents some of the results of a Round Robin Test on various typical building materials that has been carried out in the project....... of a recent Nordic project to define such a quantity, and to declare it in the form of a NORDTEST method. The Moisture Buffer Value is the figure that has been developed in the project as a way to appraise the moisture buffer effect of materials, and the value is described in the paper. Also explained...

  15. Liquid growth hormone: preservatives and buffers

    DEFF Research Database (Denmark)

    Kappelgaard, Anne-Marie; Anders, Bojesen; Skydsgaard, Karen

    2004-01-01

    injection are dependent on the preservative used in the formulation and the concentration of GH. Injection pain may also be related to the buffer substance and injection volume. A liquid formulation of GH, Norditropi SimpleXx, has been developed that dispenses with the need for reconstitution before...... solution. More pain was also reported following large volume injections and following injections with solutions containing high protein concentrations. In summary, optimization of the preservative and buffer content of a liquid GH formulation may reduce injection pain and lead to improved patient...... administration. The formulation uses phenol (3 mg/ml) as a preservative (to protect product from microbial degradation or contamination) and histidine as a buffer. Alternative preservatives used in other GH formulations include m-cresol (9 mg/ml) and benzyl alcohol (3-9 mg/ml). Buffering agents include citrate...

  16. Calculating Buffer Zones: A Guide for Applicators

    Science.gov (United States)

    Buffer zones provide distance between the application block (i.e., edge of the treated field) and bystanders, in order to control pesticide exposure risk from soil fumigants. Distance requirements may be reduced by credits such as tarps.

  17. Buffer Strips for Riparian Zone Management

    National Research Council Canada - National Science Library

    1991-01-01

    This study provides a review of technical literature concerning the width of riparian buffer strips needed to protect water quality and maintain other important values provided by riparian ecosystem...

  18. Lucas Heights buffer zone: plan of management

    International Nuclear Information System (INIS)

    1986-01-01

    This plan is being used by the Commission as a guide for its management of the Lucas Heights buffer zone, which is essentially a circular area having a 1-6 km radius around the HIFAR reactor. Aspects covered by this plan include past uses, current use, objectives for buffer zone land management, emergency evacuation, resource conservation, archaeology, fire, access, rehabilitation of disturbed areas, resource management and plan implementation

  19. Buffer regulation of calcium puff sequences

    International Nuclear Information System (INIS)

    Fraiman, Daniel; Dawson, Silvina Ponce

    2014-01-01

    Puffs are localized Ca 2+ signals that arise in oocytes in response to inositol 1,4,5-trisphosphate (IP 3 ). They are the result of the liberation of Ca 2+ from the endoplasmic reticulum through the coordinated opening of IP 3 receptor/channels clustered at a functional release site. The presence of buffers that trap Ca 2+ provides a mechanism that enriches the spatio–temporal dynamics of cytosolic calcium. The expression of different types of buffers along the cell's life provides a tool with which Ca 2+ signals and their responses can be modulated. In this paper we extend the stochastic model of a cluster of IP 3 R-Ca 2+ channels introduced previously to elucidate the effect of buffers on sequences of puffs at the same release site. We obtain analytically the probability laws of the interpuff time and of the number of channels that participate of the puffs. Furthermore, we show that under typical experimental conditions the effect of buffers can be accounted for in terms of a simple inhibiting function. Hence, by exploring different inhibiting functions we are able to study the effect of a variety of buffers on the puff size and interpuff time distributions. We find the somewhat counter-intuitive result that the addition of a fast Ca 2+ buffer can increase the average number of channels that participate of a puff. (paper)

  20. Buffer regulation of calcium puff sequences.

    Science.gov (United States)

    Fraiman, Daniel; Dawson, Silvina Ponce

    2014-02-01

    Puffs are localized Ca(2 +) signals that arise in oocytes in response to inositol 1,4,5-trisphosphate (IP3). They are the r