AGU: Geophysical Research Letters

 

Editors' Highlight

Climate warming is lowering levels of dissolved carbon in the Yukon River

Though climate warming effects on the terrestrial carbon cycle have been extensively studied and modeled at high latitudes, these effects on the transfer of carbon from land to freshwater and marine ecosystems are not as well known, especially for large arctic and subarctic river basins. Past studies suggested that the dissolved organic carbon (DOC) in such basins will increase in response to climate warming, resulting from a predicted increase in DOC release from northern peatlands. However, Striegl et al. (2005) found the opposite through their analysis of the Yukon basin. By comparing DOC export, normalized to water discharge, during the growing season from 1978 to 1980 with that taken from 2001 to 2003, they argued climate warming on frozen soils increases the flow path, residence time, and microbial mineralization of DOC in the soil active layer and groundwater, ultimately decreasing DOC export. They suggested that similar processes are occurring in other permafrost-dominated river basins and that continued warming could result in decreased DOC export by major arctic and subarctic rivers due to increased respiration of organic carbon on land.

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