Evidence for non-steady-state carbon emissions from snow-scoured alpine tundra.

• Main Authors: Knowles, John F, Blanken, Peter D, Lawrence, Corey R, Williams, Mark W
• Format: Text
• Language: unknown
• Published: CU Scholar 2019
• Subjects: permafrost; Tundra
• Online Access: https://scholar.colorado.edu/libr_oafund/108; https://scholar.colorado.edu/cgi/viewcontent.cgi?article=1110&context=libr_oafund

High-latitude warming is capable of accelerating permafrost degradation and the decomposition of previously frozen carbon. The existence of an analogous high-altitude feedback, however, has yet to be directly evaluated. We address this knowledge gap by coupling a radiocarbon-based model to 7 years (2008-2014) of continuous eddy covariance data from a snow-scoured alpine tundra meadow in Colorado, USA, where solifluction lobes are associated with discontinuous permafrost. On average, the ecosystem was a net annual source of 232 ± 54 g C m-2 (mean ± 1 standard deviation) to the atmosphere, and respiration of relatively radiocarbon-depleted (i.e., older) substrate contributes to carbon emissions during the winter. Given that alpine soils with permafrost occupy 3.6 × 106 km2 land area and are estimated to contain 66.3 Pg of soil organic carbon (4.5% of the global pool), this scenario has global implications for the mountain carbon balance and corresponding resource allocation to lower elevations.