Abrupt permafrost thaw accelerates carbon dioxide and methane release at a tussock tundra site

Heidi Rodenhizera Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USACorrespondence[email protected]

https://orcid.org/0000-0001-5824-3302 View further author information

Fay Belsheb Soil and Water Sciences Department, University of Florida, Gainesville, Florida, USAView further author information

Gerardo Celisc Agronomy Department, University of Florida, Gainesville, Florida, USA

https://orcid.org/0000-0003-1265-4063 View further author information

Justin Ledmand Bonanza Creek Long Term Ecological Research Site, University of Alaska Fairbanks, Fairbanks, Alaska, USAView further author information

Marguerite Mauritze Biological Sciences, The University of Texas at El Paso, El Paso, Texas, USA

https://orcid.org/0000-0001-8733-9119 View further author information

Scott Goetza Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA;f School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, USA

https://orcid.org/0000-0002-6326-4308 View further author information

Temuulen Sankeyf School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, USA

https://orcid.org/0000-0002-6919-8428 View further author information

Edward A.G. Schuura Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USAView further author information

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ABSTRACT

Abrupt thaw could cause permafrost ecosystems to release more carbon than is predicted from gradual thaw alone. However, thermokarst feature mapping is limited in scope, and observed responses of carbon fluxes to abrupt thaw are variable. We developed a thermokarst detection algorithm that identifies thermokarst features from a single elevation dataset with 71.5 percent accuracy and applied it in Healy, Alaska. Additionally, we investigated the landscape-level variation in carbon dioxide and methane fluxes by extent of abrupt thaw using eddy covariance. Seven percent of the site was classified as thermokarst. Water tracks were the most extensive form of thermokarst, although small pits were much more numerous. Abrupt thaw was positively correlated with carbon uptake during the growing season, when increases in gross primary productivity outpaced increases in ecosystem respiration in vegetation-dense water tracks. However, this was outweighed by higher carbon release in thermokarst features during the nongrowing season. Additionally, abrupt thaw was positively correlated with methane production nearly year-round. Our findings support the hypothesis that abrupt thaw of permafrost carbon will contribute to the permafrost climate feedback above and beyond that associated with gradual thaw and highlights the need to map thermokarst and incorporate abrupt thaw into Earth System Models.

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Acknowledgments

This study made use of imagery that was collected as part of the Arctic–Boreal Vulnerability Experiment. Resources supporting this work were provided by the NASA High-End Computing Program through the NASA Center for Climate Simulation at Goddard Space Flight Center. Particular thanks to Elizabeth Hoy and Tristan Goulden for their help with ABoVE and NEON data sets.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15230430.2022.2118639

Additional information

Funding

This work was supported by the National Science Foundation (NSF) Navigating the New Arctic: Long Term Research in Environmental Biology: The Arctic Carbon and Climate (ACCLIMATE) Observatory: Tundra Ecosystem Carbon Balance and Old Carbon Loss as a Consequence of Permafrost Degradation (Award No. 1754839). Supplemental funding was provided by the Bonanza Creek LTER, a partnership between the University of Alaska Fairbanks and the U.S. Forest Service. Significant funding for collection of these data was provided by the National Science Foundation Long-Term Ecological Research program (NSF Grant Nos. DEB-1636476, DEB-1026415, DEB-0620579, DEB-0423442, DEB-0080609, DEB-9810217, DEB-9211769, DEB-8702629) and by the U.S. Forest Service, Pacific Northwest Research Station (Agreement No. RJVA-PNW-01-JV-11261952-231).