TY - JOUR
T1 - Experimental Soil Warming and Permafrost Thaw Increase CH4 Emissions in an Upland Tundra Ecosystem
AU - Taylor, M. A.
AU - Celis, G.
AU - Ledman, J. D.
AU - Mauritz, M.
AU - Natali, S. M.
AU - Pegoraro, E. F.
AU - Schädel, C.
AU - Schuur, E. A.G.
N1 - Funding Information:
This work was based in part on support provided by the following programs: U.S. Department of Energy, Office of Biological and Environmental Research, Terrestrial Ecosystem Science (TES) Program, Award #DE‐SC0006982 and updated with DE‐SC0014085 (2015–2018); National Science Foundation Navigating the New Arctic: LTREB: The Arctic Carbon and Climate (ACCLIMATE) Observatory: Tundra Ecosystem Carbon Balance and Old Carbon Loss as a Consequence of Permafrost Degradation, Award #1754839; National Parks Inventory and Monitoring Program; National Science Foundation Bonanza Creek LTER program, Award #1026415; National Science Foundation Office of Polar Programs, Award #1203777. The authors would like to express our gratitude for assistance from researchers and technicians from the Schuur lab and Bonanza Creek LTER, especially M. Duric, C. So, and G. Frandson, who assisted in these data collections.
Funding Information:
This work was based in part on support provided by the following programs: U.S. Department of Energy, Office of Biological and Environmental Research, Terrestrial Ecosystem Science (TES) Program, Award #DE-SC0006982 and updated with DE-SC0014085 (2015–2018); National Science Foundation Navigating the New Arctic: LTREB: The Arctic Carbon and Climate (ACCLIMATE) Observatory: Tundra Ecosystem Carbon Balance and Old Carbon Loss as a Consequence of Permafrost Degradation, Award #1754839; National Parks Inventory and Monitoring Program; National Science Foundation Bonanza Creek LTER program, Award #1026415; National Science Foundation Office of Polar Programs, Award #1203777. The authors would like to express our gratitude for assistance from researchers and technicians from the Schuur lab and Bonanza Creek LTER, especially M. Duric, C. So, and G. Frandson, who assisted in these data collections.
Publisher Copyright:
© 2021. American Geophysical Union. All Rights Reserved.
PY - 2021/11
Y1 - 2021/11
N2 - Rapid Arctic warming is causing permafrost to thaw and exposing large quantities of soil organic carbon (C) to potential decomposition. In dry upland tundra systems, subsidence from thawing permafrost can increase surface soil moisture resulting in higher methane (CH4) emissions from newly waterlogged soils. The proportion of C released as carbon dioxide (CO2) and CH4 remains uncertain as previously dry landscapes transition to a thawed state, resulting in both wetter and drier microsites. To address how thaw and moisture interact to affect total C emissions, we measured CH4 and CO2 emissions from paired chambers across thaw and moisture gradients created by nine years of experimental soil warming in interior Alaska. Cumulative growing season (May–September) CH4 emissions were elevated at both wetter (216.1–1,099.4 mg CH4-C m−2) and drier (129.7–392.3 mg CH4-C m−2) deeply thawed microsites relative to shallow thaw (55.6–215.7 mg CH4-C m−2) and increased with higher deep soil temperatures and permafrost thaw depth. Interannual variability in CH4 emissions was driven by wet conditions in graminoid-dominated plots that generated >70% of emissions in a wet year. Shoulder season emissions were equivalent to growing season CH4 emissions rates in the deeply thawed, warmed soils, highlighting the importance of non-growing season CH4 emissions. Net C sink potential was reduced in deeply thawed wet plots by 4%–42%, and by 3.5%–8% in deeply thawed drier plots due to anaerobic respiration, suggesting that some dry upland tundra landscapes may transition into stronger CH4 sources in a warming Arctic.
AB - Rapid Arctic warming is causing permafrost to thaw and exposing large quantities of soil organic carbon (C) to potential decomposition. In dry upland tundra systems, subsidence from thawing permafrost can increase surface soil moisture resulting in higher methane (CH4) emissions from newly waterlogged soils. The proportion of C released as carbon dioxide (CO2) and CH4 remains uncertain as previously dry landscapes transition to a thawed state, resulting in both wetter and drier microsites. To address how thaw and moisture interact to affect total C emissions, we measured CH4 and CO2 emissions from paired chambers across thaw and moisture gradients created by nine years of experimental soil warming in interior Alaska. Cumulative growing season (May–September) CH4 emissions were elevated at both wetter (216.1–1,099.4 mg CH4-C m−2) and drier (129.7–392.3 mg CH4-C m−2) deeply thawed microsites relative to shallow thaw (55.6–215.7 mg CH4-C m−2) and increased with higher deep soil temperatures and permafrost thaw depth. Interannual variability in CH4 emissions was driven by wet conditions in graminoid-dominated plots that generated >70% of emissions in a wet year. Shoulder season emissions were equivalent to growing season CH4 emissions rates in the deeply thawed, warmed soils, highlighting the importance of non-growing season CH4 emissions. Net C sink potential was reduced in deeply thawed wet plots by 4%–42%, and by 3.5%–8% in deeply thawed drier plots due to anaerobic respiration, suggesting that some dry upland tundra landscapes may transition into stronger CH4 sources in a warming Arctic.
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U2 - 10.1029/2021JG006376
DO - 10.1029/2021JG006376
M3 - Article
AN - SCOPUS:85119842219
SN - 2169-8953
VL - 126
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
IS - 11
M1 - e2021JG006376
ER -