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Increased Arctic NO3− Availability as a Hydrogeomorphic Consequence of Permafrost Degradation and Landscape Drying
Name
nitrogen-03-00021-v3.pdf
Size
2.66 MB
Format
Adobe PDF
Checksum (MD5)
ff9ffa91ddd1efc1a56b3b592d277ab9
Author(s)
Arendt, Carli A.
Heikoop, Jeffrey M.
Newman, Brent D.
Wilson, Cathy J.
Wainwright, Haruko
Kumar, Jitendra
Andersen, Christian G.
Wales, Nathan A.
Dafflon, Baptiste
Cherry, Jessica
Date Issued
May 21, 2022
Publisher
Multidisciplinary Digital Publishing Institute
Citation
Nitrogen 3 (2): 314-332 (2022)
Version
Final published version
Abstract
Climate-driven permafrost thaw alters the strongly coupled carbon and nitrogen cycles within the Arctic tundra, influencing the availability of limiting nutrients including nitrate (NO3−). Researchers have identified two primary mechanisms that increase nitrogen and NO3− availability within permafrost soils: (1) the ‘frozen feast’, where previously frozen organic material becomes available as it thaws, and (2) ‘shrubification’, where expansion of nitrogen-fixing shrubs promotes increased soil nitrogen. Through the synthesis of original and previously published observational data, and the application of multiple geospatial approaches, this study investigates and highlights a third mechanism that increases NO3− availability: the hydrogeomorphic evolution of polygonal permafrost landscapes. Permafrost thaw drives changes in microtopography, increasing the drainage of topographic highs, thus increasing oxic conditions that promote NO3− production and accumulation. We extrapolate relationships between NO3− and soil moisture in elevated topographic features within our study area and the broader Alaskan Coastal Plain and investigate potential changes in NO3− availability in response to possible hydrogeomorphic evolution scenarios of permafrost landscapes. These approximations indicate that such changes could increase Arctic tundra NO3− availability by ~250–1000%. Thus, hydrogeomorphic changes that accompany continued permafrost degradation in polygonal permafrost landscapes will substantially increase soil pore water NO3− availability and boost future fertilization and productivity in the Arctic.
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DOI of Published Version
http://dx.doi.org/10.3390/nitrogen3020021
