Regulation of Decomposition and Methane Dynamics across Natural, Commercially Mined, and Restored Northern Peatlands

Basiliko, Nathan; Blodau, Christian; Roehm, C. L.; Bengtson, Per; Moore, Tim R.

doi:10.1007/s10021-007-9083-2

Cited by 94 publications

(106 citation statements)

References 41 publications

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“…The largest differences between the baseline-parameter CLM4Me and inversion predictions were in the 20 • S-10 • S, 40 • N-50 • N, and 50 • N-60 • N latitude bands. The excessive production in the 20 • S-10 • S band (for the baseline parameter case) can be explained by the high CLM4 GPP bias in the Amazon (Beer et al, 2010). This comparison is crude, since the ranges on the bottom-up and top-down estimates span different time periods and spatial resolutions.…”

Section: Comparison To Top-down Ch 4 Flux Estimatesmentioning

confidence: 99%

“…The hypothesized reason for acetogenotrophic methanogenesis having higher temperature sensitivity than fermenters or aerobic decomposers is that acetogenotrophic methanogenesis is barely enthalpically favorable, so the primary Gibbs free energy release comes from the increase in entropy associated with the disintegration of acetate into two gas molecules (one CH 4 and one CO 2 ). In any case, this temperature sensitivity will not be relevant for net CH 4 emissions unless ample substrate is available for methanogenesis, while a number of studies (Bergman et al, 1998;Basiliko et al, 2007) and one review (Whalen, 2005) suggest that high-latitude methanogenesis is primarily substrate limited, and accelerating decomposition under increased temperatures could cause depletion of substrate for methanogenesis.…”

Section: Temperaturementioning

confidence: 99%

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Barriers to predicting changes in global terrestrial methane fluxes: analyses using CLM4Me, a methane biogeochemistry model integrated in CESM

et al. 2011

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Abstract. Terrestrial net CH 4 surface fluxes often represent the difference between much larger gross production and consumption fluxes and depend on multiple physical, biological, and chemical mechanisms that are poorly understood and represented in regional-and global-scale biogeochemical models. To characterize uncertainties, study feedbacks between CH 4 fluxes and climate, and to guide future model development and experimentation, we developed and tested a new CH 4 biogeochemistry model (CLM4Me) integrated in the land component (Community Land Model; CLM4) of the Community Earth System Model (CESM1). CLM4Me includes representations of CH 4 production, oxidation, aerenchyma transport, ebullition, aqueous and gaseous diffusion, and fractional inundation. As with most global models, CLM4 lacks important features for predicting current and future CH 4 fluxes, including: vertical representation of soil organic matter, accurate subgrid scale hydrology, realistic representation of inundated system vegetation, anaerobic decomposition, thermokarst dynamics, and aqueous chemistry. We compared the seasonality and magnitude of predicted CH 4 emissions to observations from 18 sites and three global atmospheric inversions. Simulated net CH 4 emissions using our baseline parameter set were 270, 160, 50, and 70 Tg CH 4 yr −1 globally, in the tropics, in the temperate zone, and north of 45 • N, respectively; these values are within the range of previous estimates. We then used the model to characterize the sensitivity of regional and global CH 4 emission estimates to uncertainties in model paCorrespondence to: W. J. Riley (wjriley@lbl.gov) rameterizations. Of the parameters we tested, the temperature sensitivity of CH 4 production, oxidation parameters, and aerenchyma properties had the largest impacts on net CH 4 emissions, up to a factor of 4 and 10 at the regional and gridcell scales, respectively. In spite of these uncertainties, we were able to demonstrate that emissions from dissolved CH 4 in the transpiration stream are small (<1 Tg CH 4 yr −1 ) and that uncertainty in CH 4 emissions from anoxic microsite production is significant. In a 21st century scenario, we found that predicted declines in high-latitude inundation may limit increases in high-latitude CH 4 emissions. Due to the high level of remaining uncertainty, we outline observations and experiments that would facilitate improvement of regional and global CH 4 biogeochemical models.

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Section: Comparison To Top-down Ch 4 Flux Estimatesmentioning

confidence: 99%

Section: Temperaturementioning

confidence: 99%

Barriers to predicting changes in global terrestrial methane fluxes: analyses using CLM4Me, a methane biogeochemistry model integrated in CESM

et al. 2011

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“…At sites IP1-5 and DP1-3, R eco was measured with a static polycarbonate chamber (60 × 60 × 33 cm) equipped with two internal fans to ensure mixing of the air within the chamber and a cooling system (submerged ice packs and water pumped to a radiator located within the chamber) to maintain the temperature within the chamber close to the ambient air temperature (for a more detailed description, see Alm et al, 2007b). At IP6, R eco was measured with a CPY-4 (PP Systems, UK) clear acrylic chamber (14.6 cm diameter, 14.5 cm height).…”

Section: Field Measurementsmentioning

confidence: 99%

“…A flux was accepted if the coefficient of determination (r 2 ) was at least 0.90. An exception was made in cases where the flux was close to 0 (mainly in wintertime when soil processes are typically slower) and the r 2 is always low (Alm et al, 2007b). In these cases the flux data were examined graphically, and fluxes with obvious non-linearity (due to chamber leakage, fan malfunction, etc.)…”

Section: Flux Calculationsmentioning

confidence: 99%

“…In this study, we followed the sign convention whereby positive values indicated a CO 2 -C flux from the peatland to the atmosphere (source) and negative values indicated a flux from the atmosphere to the peatland (sink). Gross primary production (GPP) was calculated as NEE minus R eco (Alm et al, 2007b), and the closest R eco flux value in time to a NEE flux value was used.…”

Section: Flux Calculationsmentioning

confidence: 99%

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Derivation of greenhouse gas emission factors for peatlands managed for extraction in the Republic of Ireland and the United Kingdom

Wilson¹,

Dixon

Artz

et al. 2015

Biogeosciences

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Abstract. Drained peatlands are significant hotspots of carbon dioxide (CO 2 ) emissions and may also be more vulnerable to fire with its associated gaseous emissions. Under the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol, greenhouse gas (GHG) emissions from peatlands managed for extraction are reported on an annual basis. However, the Tier 1 (default) emission factors (EFs) provided in the IPCC 2013 Wetlands Supplement for this land use category may not be representative in all cases and countries are encouraged to move to highertier reporting levels with reduced uncertainty levels based on country-or regional-specific data. In this study, we quantified (1) CO 2 -C emissions from nine peat extraction sites in the Republic of Ireland and the United Kingdom, which were initially disaggregated by land use type (industrial versus domestic peat extraction), and (2) a range of GHGs that are released to the atmosphere with the burning of peat. Drainagerelated methane (CH 4 ) and nitrous oxide (N 2 O) emissions as well as CO 2 -C emissions associated with the off-site decomposition of horticultural peat were not included here. Our results show that net CO 2 -C emissions were strongly controlled by soil temperature at the industrial sites (bare peat) and by soil temperature and leaf area index at the vegetated domestic sites. Our derived EFs of 1.70 (±0.47) and 1.64 (±0.44) t CO 2 -C ha −1 yr −1 for the industrial and domestic sites respectively are considerably lower than the Tier 1 EF (2.8 ± 1.7 t CO 2 -C ha −1 yr −1 ) provided in the Wetlands Supplement. We propose that the difference between our derived values and the Wetlands Supplement value is due to differences in peat quality and, consequently, decomposition rates. Emissions from burning of the peat (g kg −1 dry fuel burned) were estimated to be approximately 1346 CO 2 , 8.35 methane (CH 4 ), 218 carbon monoxide (CO), 1.53 ethane (C 2 H 6 ), 1.74 ethylene (C 2 H 4 ), 0.60 methanol (CH 3 OH), 2.21 hydrogen cyanide (HCN) and 0.73 ammonia (NH 3 ), and this emphasises the importance of understanding the full suite of trace gas emissions from biomass burning. Our results highlight the importance of generating reliable Tier 2 values for different regions and land use categories. Furthermore, given that the IPCC Tier 1 EF was only based on 20 sites (all from Canada and Fennoscandia), we suggest that data from another 9 sites significantly expand the global data set, as well as adding a new region.

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Degradation Reduces Microbial Richness and Alters Microbial Functions in an Australian Peatland

et al. 2022

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Peatland ecosystems cover only 3% of the world’s land area; however, they store one-third of the global soil carbon (C). Microbial communities are the main drivers of C decomposition in peatlands, yet we have limited knowledge of their structure and function. While the microbial communities in the Northern Hemisphere peatlands are well documented, we have limited understanding of microbial community composition and function in the Southern Hemisphere peatlands, especially in Australia. We investigated the vertical stratification of prokaryote and fungal communities from Wellington Plains peatland in the Australian Alps. Within the peatland complex, bog peat was sampled from the intact peatland and dried peat from the degraded peatland along a vertical soil depth gradient (i.e., acrotelm, mesotelm, and catotelm). We analyzed the prokaryote and fungal community structure, predicted functional profiles of prokaryotes using PICRUSt, and assigned soil fungal guilds using FUNGuild. We found that the structure and function of prokaryotes were vertically stratified in the intact bog. Soil carbon, manganese, nitrogen, lead, and sodium content best explained the prokaryote composition. Prokaryote richness was significantly higher in the intact bog acrotelm compared to degraded bog acrotelm. Fungal composition remained similar across the soil depth gradient; however, there was a considerable increase in saprotroph abundance and decrease in endophyte abundance along the vertical soil depth gradient. The abundance of saprotrophs and plant pathogens was two-fold higher in the degraded bog acrotelm. Soil manganese and nitrogen content, electrical conductivity, and water table level (cm) best explained the fungal composition. Our results demonstrate that both fungal and prokaryote communities are shaped by soil abiotic factors and that peatland degradation reduces microbial richness and alters microbial functions. Thus, current and future changes to the environmental conditions in these peatlands may lead to altered microbial community structures and associated functions which may have implications for broader ecosystem function changes in peatlands.

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Regulation of Decomposition and Methane Dynamics across Natural, Commercially Mined, and Restored Northern Peatlands

Cited by 94 publications

References 41 publications

Barriers to predicting changes in global terrestrial methane fluxes: analyses using CLM4Me, a methane biogeochemistry model integrated in CESM

Barriers to predicting changes in global terrestrial methane fluxes: analyses using CLM4Me, a methane biogeochemistry model integrated in CESM

Derivation of greenhouse gas emission factors for peatlands managed for extraction in the Republic of Ireland and the United Kingdom

Degradation Reduces Microbial Richness and Alters Microbial Functions in an Australian Peatland

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