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Euskirchen ES, Edgar CW, Kane ES, Waldrop MP, Neumann RB, Manies KL, Douglas TA, Dieleman C, Jones MC, Turetsky MR. Persistent net release of carbon dioxide and methane from an Alaskan lowland boreal peatland complex. GLOBAL CHANGE BIOLOGY 2024; 30:e17139. [PMID: 38273498 DOI: 10.1111/gcb.17139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 11/20/2023] [Accepted: 12/18/2023] [Indexed: 01/27/2024]
Abstract
Permafrost degradation in peatlands is altering vegetation and soil properties and impacting net carbon storage. We studied four adjacent sites in Alaska with varied permafrost regimes, including a black spruce forest on a peat plateau with permafrost, two collapse scar bogs of different ages formed following thermokarst, and a rich fen without permafrost. Measurements included year-round eddy covariance estimates of net carbon dioxide (CO2 ), mid-April to October methane (CH4 ) emissions, and environmental variables. From 2011 to 2022, annual rainfall was above the historical average, snow water equivalent increased, and snow-season duration shortened due to later snow return. Seasonally thawed active layer depths also increased. During this period, all ecosystems acted as slight annual sources of CO2 (13-59 g C m-2 year-1 ) and stronger sources of CH4 (11-14 g CH4 m-2 from ~April to October). The interannual variability of net ecosystem exchange was high, approximately ±100 g C m-2 year-1 , or twice what has been previously reported across other boreal sites. Net CO2 release was positively related to increased summer rainfall and winter snow water equivalent and later snow return. Controls over CH4 emissions were related to increased soil moisture and inundation status. The dominant emitter of carbon was the rich fen, which, in addition to being a source of CO2 , was also the largest CH4 emitter. These results suggest that the future carbon-source strength of boreal lowlands in Interior Alaska may be determined by the area occupied by minerotrophic fens, which are expected to become more abundant as permafrost thaw increases hydrologic connectivity. Since our measurements occur within close proximity of each other (≤1 km2 ), this study also has implications for the spatial scale and data used in benchmarking carbon cycle models and emphasizes the necessity of long-term measurements to identify carbon cycle process changes in a warming climate.
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Affiliation(s)
- Eugénie S Euskirchen
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Colin W Edgar
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Evan S Kane
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan, USA
- Northern Research Station, USDA Forest Service, Houghton, Michigan, USA
| | - Mark P Waldrop
- U.S. Geological Survey, Geology, Minerals, Energy, and Geophysics Science Center, Moffett Fields, Mountain View, California, USA
| | - Rebecca B Neumann
- Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA
| | - Kristen L Manies
- U.S. Geological Survey, Geology, Minerals, Energy, and Geophysics Science Center, Moffett Fields, Mountain View, California, USA
| | - Thomas A Douglas
- U.S. Army Cold Regions Research & Engineering Laboratory, Fort Wainwright, Fairbanks, Alaska, USA
| | - Catherine Dieleman
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Miriam C Jones
- U.S. Geological Survey, Florence Bascom Geoscience Center, Reston, Virginia, USA
| | - Merritt R Turetsky
- Institute of Arctic and Alpine Research, Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
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Shao P, Han H, Sun J, Yang H, Xie H. Salinity Effects on Microbial Derived-C of Coastal Wetland Soils in the Yellow River Delta. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.872816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Microorganisms play a crucial role in regulating the turnover and transformation of soil organic carbon (SOC), whereas microbial contribution to SOC formation and storage is still unclear in coastal wetlands. In this study, we collected topsoil (0–20 cm) with 7 salinity concentrations and explored the shifts in microbial residues [represented by amino sugar (AS)] and their contribution to the SOC pool of coastal wetlands in the Yellow River delta. The gradually increasing soil salinity reduced soil water content (SWC), SOC, and soil nitrogen (N), especially in high salinity soils of coastal wetlands. Total ASs and their ratio to SOC, respectively, decreased by 90.56 and 66.35% from low salinity to high salinity soils, indicating that coastal wetlands with high salinity restrained microbial residue accumulation and microbial residue-C retention in the SOC pool. Together with redundancy analysis and path analysis, we found that SWC, pH, SOC, soil N, and glucosamine/muramic arid were positively associated with the ratio of ASs to SOC. The higher available soil resource (i.e., water, C substrate, and nutrient) increased microbial residue accumulation, promoting microbial derived-C contribution to SOC in low salinity coastal wetlands. The greatly decreased microbial residue contribution to SOC might be ascribed to microbial stress strategy and low available C substrate in coastal wetlands with high salinity concentration. Additionally, the gradually increasing salinity reduced fungal residue contribution to SOC but did not change bacterial residue contribution to SOC. These findings indicated that changed fungal residues would substantially influence SOC storage. Our study elucidates microbial contribution to SOC pool through residue reservoir in coastal wetlands and pushes microbial metabolites to a new application in global wetland SOC cycling.
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Xia S, Song Z, Li Q, Guo L, Yu C, Singh BP, Fu X, Chen C, Wang Y, Wang H. Distribution, sources, and decomposition of soil organic matter along a salinity gradient in estuarine wetlands characterized by C:N ratio, δ 13 C-δ 15 N, and lignin biomarker. GLOBAL CHANGE BIOLOGY 2021; 27:417-434. [PMID: 33068483 DOI: 10.1111/gcb.15403] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/25/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
Despite increasing recognition of the critical role of coastal wetlands in mitigating climate change, sea-level rise, and salinity increase, soil organic carbon (SOC) sequestration mechanisms in estuarine wetlands remain poorly understood. Here, we present new results on the source, decomposition, and storage of SOC in estuarine wetlands with four vegetation types, including single Phragmites australis (P, habitat I), a mixture of P. australis and Suaeda salsa (P + S, habitat II), single S. salsa (S, habitat III), and tidal flat (TF, habitat IV) across a salinity gradient. Values of δ13 C increased with depth in aerobic soil layers (0-40 cm) but slightly decreased in anaerobic soil layers (40-100 cm). The δ15 N was significantly enriched in soil organic matter at all depths than in the living plant tissues, indicating a preferential decomposition of 14 N-enriched organic components. Thus, the kinetic isotope fractionation during microbial degradation and the preferential substrate utilization are the dominant mechanisms in regulating isotopic compositions in aerobic and anaerobic conditions, respectively. Stable isotopic (δ13 C and δ15 N), elemental (C and N), and lignin composition (inherited (Ad/Al)s and C/V) were not completely consistent in reflecting the differences in SOC decomposition or accumulation among four vegetation types, possibly due to differences in litter inputs, root distributions, substrate quality, water-table level, salinity, and microbial community composition/activity. Organic C contents and storage decreased from upstream to downstream, likely due to primarily changes in autochthonous sources (e.g., decreased onsite plant biomass input) and allochthonous materials (e.g., decreased fluvially transported upland river inputs, and increased tidally induced marine algae and phytoplankton). Our results revealed that multiple indicators are essential to unravel the degree of SOC decomposition and accumulation, and a combination of C:N ratios, δ13 C, δ15 N, and lignin biomarker provides a robust approach to decipher the decomposition and source of sedimentary organic matter along the river-estuary-ocean continuum.
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Affiliation(s)
- Shaopan Xia
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Tianjin, China
| | - Zhaoliang Song
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Tianjin, China
| | - Qiang Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Tianjin, China
| | - Laodong Guo
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Changxun Yu
- Department of Biology and Environmental Science, Linnaeus University, Kalmar, Sweden
| | - Bhupinder Pal Singh
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW, Australia
| | - Xiaoli Fu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China
| | - Chunmei Chen
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China
| | - Yidong Wang
- Tianjin Key Laboratory of Water Resources and Environment, School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin, China
| | - Hailong Wang
- School of Environmental and Chemical Engineering, Foshan University, Foshan, Guangdong, China
- School of Environmental and Resource Sciences, Zhejiang A&F University, Hangzhou, Zhejiang, China
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McGuire AD, Zhu Z, Birdsey R, Pan Y, Schimel DS. Introduction to the Alaska Carbon Cycle Invited Feature. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1938-1939. [PMID: 30286257 DOI: 10.1002/eap.1808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 08/21/2018] [Accepted: 08/30/2018] [Indexed: 06/08/2023]
Affiliation(s)
- A D McGuire
- U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Z Zhu
- U.S. Geological Survey, Reston, Virginia, 12201, USA
| | - R Birdsey
- Woods Hole Research Center, Falmouth, Massachusetts, 02540, USA
| | - Y Pan
- U.S. Department of Agriculture, Forest Service, Durham, New Hampshire, 03824, USA
| | - D S Schimel
- Jet Propulsion Laboratory, Pasadena, California, 91109, USA
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McGuire AD, Genet H, Lyu Z, Pastick N, Stackpoole S, Birdsey R, D'Amore D, He Y, Rupp TS, Striegl R, Wylie BK, Zhou X, Zhuang Q, Zhu Z. Assessing historical and projected carbon balance of Alaska: A synthesis of results and policy/management implications. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1396-1412. [PMID: 29923353 DOI: 10.1002/eap.1768] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/25/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
We summarize the results of a recent interagency assessment of land carbon dynamics in Alaska, in which carbon dynamics were estimated for all major terrestrial and aquatic ecosystems for the historical period (1950-2009) and a projection period (2010-2099). Between 1950 and 2009, upland and wetland (i.e., terrestrial) ecosystems of the state gained 0.4 Tg C/yr (0.1% of net primary production, NPP), resulting in a cumulative greenhouse gas radiative forcing of 1.68 × 10-3 W/m2 . The change in carbon storage is spatially variable with the region of the Northwest Boreal Landscape Conservation Cooperative (LCC) losing carbon because of fire disturbance. The combined carbon transport via various pathways through inland aquatic ecosystems of Alaska was estimated to be 41.3 Tg C/yr (17% of terrestrial NPP). During the projection period (2010-2099), carbon storage of terrestrial ecosystems of Alaska was projected to increase (22.5-70.0 Tg C/yr), primarily because of NPP increases of 10-30% associated with responses to rising atmospheric CO2 , increased nitrogen cycling, and longer growing seasons. Although carbon emissions to the atmosphere from wildfire and wetland CH4 were projected to increase for all of the climate projections, the increases in NPP more than compensated for those losses at the statewide level. Carbon dynamics of terrestrial ecosystems continue to warm the climate for four of the six future projections and cool the climate for only one of the projections. The attribution analyses we conducted indicated that the response of NPP in terrestrial ecosystems to rising atmospheric CO2 (~5% per 100 ppmv CO2 ) saturates as CO2 increases (between approximately +150 and +450 ppmv among projections). This response, along with the expectation that permafrost thaw would be much greater and release large quantities of permafrost carbon after 2100, suggests that projected carbon gains in terrestrial ecosystems of Alaska may not be sustained. From a national perspective, inclusion of all of Alaska in greenhouse gas inventory reports would ensure better accounting of the overall greenhouse gas balance of the nation and provide a foundation for considering mitigation activities in areas that are accessible enough to support substantive deployment.
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Affiliation(s)
- A David McGuire
- U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Hélène Genet
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Zhou Lyu
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Neal Pastick
- Stinger Ghaffarian Technologies Inc., contractor to the U.S. Geological Survey, Sioux Falls, South Dakota, 57198, USA
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, 55108, USA
| | - Sarah Stackpoole
- Water Mission Area, Denver Federal Center, MS413, U.S. Geological Survey, Denver, Colorado, 80225, USA
| | - Richard Birdsey
- Woods Hole Research Center, Falmouth, Massachusetts, 02540, USA
| | - David D'Amore
- U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Juneau, Alaska, 99801, USA
| | - Yujie He
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - T Scott Rupp
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Robert Striegl
- National Research Program, U.S. Geological Survey, 3215 Marine Street, Boulder, Colorado, 80303, USA
| | - Bruce K Wylie
- The Earth Resources Observation Systems Center, U.S. Geological Survey, Sioux Falls, South Dakota, 57198, USA
| | - Xiaoping Zhou
- U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland, Oregon, 97208, USA
| | - Qianlai Zhuang
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Zhiliang Zhu
- U.S. Geological Survey, Reston, Virginia, 12201, USA
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