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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Sustainable Agricultural Systems Laboratory » Research » Publications at this Location » Publication #413336
Research Project: Soil, Crop, and Manure Biochemistry and Molecular Ecology: Bridging Knowledge Gaps in Microbiome Response to Management and Climate Change

Location: Sustainable Agricultural Systems Laboratory

Title: Carbon fate, iron dissolution, and molecular characterization of dissolved organic matter in Yedoma permafrost thaw under varying redox conditions

Author
item BARRETO, MATHEUS - University Of Delaware
item WANI, RUCHA - University Of Southern California
item GORANOV, ALEKSANDAR - Old Dominion University
item COWARD, ELIZABETH - University Of Delaware
item SOWERS, TYLER - Us Environmental Protection Agency (EPA)
item Fischel, Matthew
item DOUGLAS, THOMAS - Environmental Laboratory, Us Army Engineer Research And Development Center, Waterways Experiment St
item HATCHER, PATRICK - Old Dominion University
item SPARKS, DONALD - University Of Delaware

Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2024
Publication Date: 2/22/2024
Citation: Barreto, M., Wani, R., Goranov, A., Coward, E., Sowers, T., Fischel, M.H., Douglas, T., Hatcher, P., Sparks, D. 2024. Carbon fate, iron dissolution, and molecular characterization of dissolved organic matter in Yedoma permafrost thaw under varying redox conditions. Environmental Science and Technology. https://doi.org/10.1021/acs.est.3c08219.
DOI: https://doi.org/10.1021/acs.est.3c08219

Interpretive Summary: Permafrost is permanently frozen soil that occurs near the polar regions on Earth that contains massive amounts of organic carbon. However, climate change threatens to cause these soils to thaw, releasing much of the stored carbon as climate-change-causing gases, which can further accelerate warming. This study determined how thawing conditions impacted the amount of carbon lost in the permafrost soils. The experiments showed much more carbon was lost if the soils were thawed while exposed to air containing oxygen, compared to those in an oxygen-devoid environment. The results help us understand how thawing permafrost may decompose in the future and how much carbon will be released into the atmosphere. The results also help inform scientists and policymakers of risks

Technical Abstract: Arctic and boreal permafrost soils store approximately 50% of the total terrestrial C, and the Yedoma-deposits contain 25% of the total C accumulated in permafrost ecosystems. Permafrost collapse triggered by unprecedented climate warming has hazardous effects on landscape stability and water resource quantity and quality. Complicating ongoing efforts to project the ultimate fate of deep permafrost C is the poorly-constrained role of the redox environment, Fe-minerals, and redox-active phases, which may modulate organic C-abundance, composition, and reactivity through complexation and catalytic processes. We characterized C fate, Fe-fractions, and dissolved organic matter (DOM) isolates from permafrost-thaw under varying redox conditions. Under anoxic incubation conditions, 33% of the initial C is lost as gaseous species within 21 d, while the oxic incubation lost 58% of the initial C. Under anoxic incubation, 42% of the total initial C is preserved in a dissolved fraction. The lignin-like compounds dominated the permafrost-thaw, followed by lipid- and protein-like compounds. However, under anoxic incubation conditions, lipid-like compounds accumulated over time, paired with a reduction in the nominal C oxidation state, regardless of compound classes. This DOM dynamics may be affected by microbial and abiotic processes. Distinct chemodiversity signatures observed in DOM after thawing could serve as valuable proxies to track redox conditions with permafrost-thaw.