Carbon Dioxide and Methane Flux in a Dynamic Arctic Tundra Landscape: Decadal‐Scale Impacts of Ice Wedge Degradation and Stabilization

2020 ◽  
Vol 47 (22) ◽  
Author(s):  
K. P. Wickland ◽  
M. T. Jorgenson ◽  
J. C. Koch ◽  
M. Kanevskiy ◽  
R. G. Striegl
Keyword(s):  
Carbon Dioxide ◽  
Methane Flux ◽  
Arctic Tundra ◽  
Decadal Scale ◽  
Ice Wedge

Ecosystem modeling of methane and carbon dioxide fluxes for boreal forest sites

2001 ◽  
Vol 31 (2) ◽  
pp. 208-223 ◽  
Author(s):  
Christopher Potter ◽  
Jill Bubier ◽  
Patrick Crill ◽  
Peter Lafleur
Keyword(s):  
Carbon Dioxide ◽  
Boreal Forest ◽  
Land Surface ◽  
Net Primary Production ◽  
Ground Cover ◽  
Methane Flux ◽  
Growing Season ◽  
Ecosystem Model ◽  
Heat Fluxes ◽  
Water Levels

Predicted daily fluxes from an ecosystem model for water, carbon dioxide, and methane were compared with 1994 and 1996 Boreal Ecosystem–Atmosphere Study (BOREAS) field measurements at sites dominated by old black spruce (Picea mariana (Mill.) BSP) (OBS) and boreal fen vegetation near Thompson, Man. Model settings for simulating daily changes in water table depth (WTD) for both sites were designed to match observed water levels, including predictions for two microtopographic positions (hollow and hummock) within the fen study area. Water run-on to the soil profile from neighboring microtopographic units was calibrated on the basis of daily snowmelt and rainfall inputs to reproduce BOREAS site measurements for timing and magnitude of maximum daily WTD for the growing season. Model predictions for daily evapotranspiration rates closely track measured fluxes for stand water loss in patterns consistent with strong controls over latent heat fluxes by soil temperature during nongrowing season months and by variability in relative humidity and air temperature during the growing season. Predicted annual net primary production (NPP) for the OBS site was 158 g C·m–2 during 1994 and 135 g C·m–2 during 1996, with contributions of 75% from overstory canopy production and 25% from ground cover production. Annual NPP for the wetter fen site was 250 g C·m–2 during 1994 and 270 g C·m–2 during 1996. Predicted seasonal patterns for soil CO2 fluxes and net ecosystem production of carbon both match daily average estimates at the two sites. Model results for methane flux, which also closely match average measured flux levels of –0.5 mg CH4·m–2·day–1 for OBS and 2.8 mg CH4·m–2·day–1 for fen sites, suggest that spruce areas are net annual sinks of about –0.12 g CH4·m–2, whereas fen areas generate net annual emissions on the order of 0.3–0.85 g CH4·m–2, depending mainly on seasonal WTD and microtopographic position. Fen hollow areas are predicted to emit almost three times more methane during a given year than fen hummock areas. The validated model is structured for extrapolation to regional simulations of interannual trace gas fluxes over the entire North America boreal forest, with integration of satellite data to characterize properties of the land surface.

Arctic tundra: A source or sink for atmospheric carbon dioxide in a changing environment?

Oecologia ◽  
1982 ◽  
Vol 53 (1) ◽  
pp. 7-11 ◽  
Author(s):  
W. D. Billings ◽  
J. O. Luken ◽  
D. A. Mortensen ◽  
K. M. Peterson
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Arctic Tundra ◽  
Changing Environment ◽  
Atmospheric Carbon

scholarly journals Environmental controls on ecosystem-scale cold-season methane and carbon dioxide fluxes in an Arctic tundra ecosystem

2020 ◽  
Vol 17 (15) ◽  
pp. 4025-4042
Author(s):  
Dean Howard ◽  
Yannick Agnan ◽  
Detlev Helmig ◽  
Yu Yang ◽  
Daniel Obrist
Keyword(s):  
Carbon Dioxide ◽  
Methane Emission ◽  
Arctic Tundra ◽  
Cold Season ◽  
The Arctic ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Carbon Dioxide Fluxes ◽  
Soil Temperatures ◽  
Annual Total

Abstract. Understanding the processes that influence and control carbon cycling in Arctic tundra ecosystems is essential for making accurate predictions about what role these ecosystems will play in potential future climate change scenarios. Particularly, air–surface fluxes of methane and carbon dioxide are of interest as recent observations suggest that the vast stores of soil carbon found in the Arctic tundra are becoming more available to release to the atmosphere in the form of these greenhouse gases. Further, harsh wintertime conditions and complex logistics have limited the number of year-round and cold-season studies and hence too our understanding of carbon cycle processes during these periods. We present here a two-year micrometeorological data set of methane and carbon dioxide fluxes, along with supporting soil pore gas profiles, that provide near-continuous data throughout the active summer and cold winter seasons. Net emission of methane and carbon dioxide in one of the study years totalled 3.7 and 89 g C m−2 a−1 respectively, with cold-season methane emission representing 54 % of the annual total. In the other year, net emission totals of methane and carbon dioxide were 4.9 and 485 g C m−2 a−1 respectively, with cold-season methane emission here representing 82 % of the annual total – a larger proportion than has been previously reported in the Arctic tundra. Regression tree analysis suggests that, due to relatively warmer air temperatures and deeper snow depths, deeper soil horizons – where most microbial methanogenic activity takes place – remained warm enough to maintain efficient methane production whilst surface soil temperatures were simultaneously cold enough to limit microbial methanotrophic activity. These results provide valuable insight into how a changing Arctic climate may impact methane emission, and highlight a need to focus on soil temperatures throughout the entire active soil profile, rather than rely on air temperature as a proxy for modelling temperature–methane flux dynamics.

scholarly journals Effects of Low Temperature and Freeze-Thaw Cycles on Hydrocarbon Biodegradation in Arctic Tundra Soil

2001 ◽  
Vol 67 (11) ◽  
pp. 5107-5112 ◽  
Author(s):  
Mikael Eriksson ◽  
Jong-Ok Ka ◽  
William W. Mohn
Keyword(s):  
Carbon Dioxide ◽  
Arctic Tundra ◽  
Carbon Dioxide Production ◽  
Additional Treatment ◽  
Total Carbon ◽  
Hydrocarbon Biodegradation ◽  
Tundra Soil ◽  
Spacer Length ◽  
Freeze Thaw ◽  
Arctic Tundra Soil

ABSTRACT Degradation of petroleum hydrocarbons was monitored in microcosms with diesel fuel-contaminated Arctic tundra soil incubated for 48 days at low temperatures (−5, 0, and 7°C). An additional treatment was incubation for alternating 24-h periods at 7 and −5°C. Hydrocarbons were biodegraded at or above 0°C, and freeze-thaw cycles may have actually stimulated hydrocarbon biodegradation. Total petroleum hydrocarbon (TPH) removal over 48 days in the 7, 0, and 7 and −5°C treatments, respectively, was 450, 300, and 600 μg/g of soil. No TPH removal was observed at −5°C. Total carbon dioxide production suggested that TPH removal was due to biological mineralization. Bacterial metabolic activity, indicated by RNA/DNA ratios, was higher in the middle of the experiment (day 21) than at the start, in agreement with measured hydrocarbon removal and carbon dioxide production activities. The total numbers of culturable heterotrophs and of hydrocarbon degraders did not change significantly over the 48 days of incubation in any of the treatments. At the end of the experiment, bacterial community structure, evaluated by ribosomal intergenic spacer length analysis, was very similar in all of the treatments but the alternating 7 and −5°C treatment.

scholarly journals Environmental controls on ecosystem-scale cold season methane and carbon dioxide fluxes in an Arctic tundra ecosystem

2019 ◽  
Author(s):  
Dean Howard ◽  
Yannick Agnan ◽  
Detlev Helmig ◽  
Yu Yang ◽  
Daniel Obrist
Keyword(s):  
Carbon Dioxide ◽  
Methane Emission ◽  
Arctic Tundra ◽  
Cold Season ◽  
The Arctic ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Carbon Dioxide Fluxes ◽  
Soil Temperatures ◽  
Annual Total

Abstract. Understanding the processes that influence and control carbon cycling in Arctic tundra ecosystems is essential for making accurate predictions about what role these ecosystems will play in potential future climate change scenarios. Particularly, air–surface fluxes of methane and carbon dioxide are of interest as recent observations suggest that the vast stores of soil carbon found in the Arctic tundra are becoming more available to release to the atmosphere in the form of these greenhouse gases. Further, harsh wintertime conditions and complex logistics have limited the number of year-round and cold season studies and hence too our understanding of carbon cycle processes during these periods. We present here a two-year micrometeorological data set of methane and carbon dioxide fluxes that provides near-continuous data throughout the active summer and cold winter seasons. Net emission of methane and carbon dioxide in one of the study years totalled 3.7 and 89 g C m−2 a−1 respectively, with cold season methane emission representing 54% of the annual total. In the other year, net emission totals of methane and carbon dioxide were 4.9 and 485 g C m−2 a−1 respectively, with cold season methane emission here representing 82 % of the annual total – a larger proportion than has been previously reported in the Arctic tundra. Regression tree analysis suggests that, due to relatively warmer air temperatures and deeper snow depths, deeper soil horizons – where most microbial methanogenic activity takes place – remained warm enough to maintain efficient methane production whilst surface soil temperatures were simultaneously cold enough to limit microbial methanotrophic activity. These results provide valuable insight into how a changing Arctic climate may impact methane emission, and highlight a need to focus on soil temperatures throughout the entire active soil profile, rather than rely on air temperature as a proxy for modelling temperature–methane flux dynamics.

Post-fire carbon dioxide emissions from a peatland undergoing restoration

2021 ◽  
Author(s):  
Rebekka Artz ◽  
Mhairi Coyle ◽  
Pete Gilbert ◽  
Roxane Andersen ◽  
Adrian Bass
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Emissions ◽  
Methane Flux ◽  
Slope Aspect ◽  
Unesco World Heritage ◽  
Greenhouse Gas Flux ◽  
Significant Damage ◽  
Blanket Bog ◽  
One Year ◽  
The Uk

<p>In May 2019, a major wildfire event affected >60 km2 within the 4000 km2 Flow Country in Northern Scotland, UK, a flagship blanket bog peatland that is being considered for UNESCO World Heritage Status. While the fire itself created significant damage, it also led to an extraordinary and unique opportunity to compare burned and unburned landscape scale greenhouse gas flux and surface energy dynamics using sites that, crucially, have otherwise identical biophysical characteristics (slope, aspect, peat depth) and land management histories. Since September 2019, carbon dioxide and methane flux data have been collected alongside other micrometeorological variables. Due to the COVID-19 lockdown in the UK, the team had severe difficulties in maintaining the equipment and hence, only partial and preliminary data will be reported here to showcase the findings from this project to date. The data obtained so far suggest a post-fire reduction in net CO2 emissions for a period of one year since the beginning of our monitoring campaign.</p>

Recent change of Arctic tundra ecosystems from a net carbon dioxide sink to a source

Nature ◽  
1993 ◽  
Vol 361 (6412) ◽  
pp. 520-523 ◽  
Author(s):  
Walter C. Oechel ◽  
Steven J. Hastings ◽  
George Vourlrtis ◽  
Mitchell Jenkins ◽  
George Riechers ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Arctic Tundra ◽  
Recent Change ◽  
Tundra Ecosystems
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