Coupling plant litter quantity to a novel metric for litter quality explains C storage changes in a thawing permafrost peatland
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- Ecology &, Evolutionary Biology Department University of Arizona Tucson Arizona USA, Department of Environmental Science University of Arizona Tucson Arizona USA
- Environmental Sciences Graduate Program The Ohio State University Columbus Ohio USA
- Department of Environmental Science University of Arizona Tucson Arizona USA
- Department of Biology Terrestrial Ecology University of Copenhagen Copenhagen Denmark, Center for Permafrost (CENPERM) Department of Geosciences and Natural Resource Management University of Copenhagen Copenhagen Denmark
- Florida State University Earth Ocean and Atmospheric Sciences Tallahassee Florida USA
- Department of Earth Sciences and Institute for the Study of Earth, Oceans and Space University of New Hampshire Durham New Hampshire USA
- Lawrence Berkeley Laboratory Climate and Ecosystem Sciences Division Berkeley California USA
- Civil Environmental and Geodetic Engineering The Ohio State University Columbus Ohio USA
- Department of Geological Sciences and Bolin Centre for Climate Research Stockholm University Stockholm Sweden
- Lawrence Livermore National Laboratory Livermore California USA
- Climate Impacts Research Centre—Department of Ecology and Environmental Sciences Umeå University Abisko Sweden
- Ecology &, Evolutionary Biology Department University of Arizona Tucson Arizona USA
- Department of Environmental Science University of Arizona Tucson Arizona USA, Microbiology Department The Ohio State University Columbus Ohio USA, Center of Microbiome Science The Ohio State University Columbus Ohio USA, The Byrd Polar and Climate Research Center The Ohio State University Columbus Ohio USA
Abstract Permafrost thaw is a major potential feedback source to climate change as it can drive the increased release of greenhouse gases carbon dioxide (CO 2 ) and methane (CH 4 ). This carbon release from the decomposition of thawing soil organic material can be mitigated by increased net primary productivity (NPP) caused by warming, increasing atmospheric CO 2 , and plant community transition. However, the net effect on C storage also depends on how these plant community changes alter plant litter quantity, quality, and decomposition rates. Predicting decomposition rates based on litter quality remains challenging, but a promising new way forward is to incorporate measures of the energetic favorability to soil microbes of plant biomass decomposition. We asked how the variation in one such measure, the nominal oxidation state of carbon (NOSC), interacts with changing quantities of plant material inputs to influence the net C balance of a thawing permafrost peatland. We found: (1) Plant productivity (NPP) increased post‐thaw, but instead of contributing to increased standing biomass, it increased plant biomass turnover via increased litter inputs to soil; (2) Plant litter thermodynamic favorability (NOSC) and decomposition rate both increased post‐thaw, despite limited changes in bulk C:N ratios; (3) these increases caused the higher NPP to cycle more rapidly through both plants and soil, contributing to higher CO 2 and CH 4 fluxes from decomposition. Thus, the increased C‐storage expected from higher productivity was limited and the high global warming potential of CH 4 contributed a net positive warming effect. Although post‐thaw peatlands are currently C sinks due to high NPP offsetting high CO 2 release, this status is very sensitive to the plant community's litter input rate and quality. Integration of novel bioavailability metrics based on litter chemistry, including NOSC, into studies of ecosystem dynamics, is needed to improve the understanding of controls on arctic C stocks under continued ecosystem transition.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER); Howard Hughes Medical Institute; National Science Foundation (NSF); Northern Ecosystems Research for Undergraduates (NERU)
- Grant/Contract Number:
- DE‐SC0010580; DE‐SC0016440; DE‐SC0021349; DE‐AC02‐05CH11231; AC02-05CH11231; SC0021349; SC0010580: SC0016440; 5200642; 2022070; EAR-1063037
- OSTI ID:
- 1830863
- Alternate ID(s):
- OSTI ID: 1830865; OSTI ID: 1863928
- Journal Information:
- Global Change Biology, Journal Name: Global Change Biology Vol. 28 Journal Issue: 3; ISSN 1354-1013
- Publisher:
- Wiley-BlackwellCopyright Statement
- Country of Publication:
- United Kingdom
- Language:
- English
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