| Autor: |
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, Wullschleger, Stan D. |
| Předmět: |
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| Zdroj: |
Nitrogen (2504-3129); Jun2022, Vol. 3 Issue 2, p314-332, 19p |
| Abstrakt: |
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. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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