Map of the Yukon-Kuskokwim Delta in Alaska
Map of the Yukon-Kuskokwim Delta in Alaska outlining in red the outer border of wildfires that occurred in 2015. The yellow points are the aquatic ecosystems that were sampled. Credit: Zolkos et al. [2022], Figure 1 (top left panel)
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Biogeosciences

Arctic regions are disproportionally affected by climate change, resulting in increases in wildfire frequency. Wildfires can profoundly affect the biogeochemistry of tundra ecosystems. In these permafrost environments, postfire effects include large amounts of nutrients and carbon released into aquatic ecosystems, and changes in vegetation and hydrology. But these changes are not uniform across the Arctic landscape. A more concrete understanding of the role of the Arctic landscape and its mosaic of land features is needed to further our knowledge of wildfires in northern ecosystems.

Zolkos et al. [2022] address this gap by measuring changes in surface and pore water chemistry variables across landscape gradients within streams, lakes, and fen and peat ponds, of the Yukon-Kuskokwim Delta, Alaska, following high wildfire activity in 2015. In general, wildfires reduced organic carbon and CO2 in surface water but increased inorganic constituents and nitrogen cycling. Response and recovery to wildfire depended on landscape characteristics. Aquatic environments found in higher elevation and within smaller watersheds revealed enhanced carbon cycling due to their strong linkages with their terrestrial surroundings. Lower in the landscape, enhanced nitrogen cycling along stream riparian corridors was the major response to wildfire.

Citation: Zolkos, S., MacDonald, E., Hung, J. K. Y., Schade, J. D., Ludwig, S., Mann, P. J., et al. (2022). Physiographic controls and wildfire effects on aquatic biogeochemistry in tundra of the Yukon-Kuskokwim Delta, Alaska. Journal of Geophysical Research: Biogeosciences, 127, e2022JG006891.

—Marguerite A. Xenopoulos, Editor in Chief, Journal of Geophysical Research: Biogeosciences

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