Rates and radiocarbon content of summer ecosystem respiration in response to long‐term deeper snow in the High Arctic of NW Greenland. Issue 6 (16th June 2014)

• Record Type: Journal Article
• Authors: Lupascu, M.; Welker, J. M.; Xu, X.; Czimczik, C. I.
• Is Part Of: Journal of geophysical research. Volume 119:Issue 6(2014)
• Page Start: 1180
• Page End: 1194
• Publication Date: 2014-06-16
• Subjects: Geobiology -- Periodicals; Biogeochemistry -- Periodicals; Biotic communities -- Periodicals; Geophysics -- Periodicals; 577.14
• DOI: 10.1002/2013JG002494
• Languages: English
• ISSNs: 2169-8953

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>The amount and timing of snow cover control the cycling of carbon (C), water, and energy in arctic ecosystems. The implications of changing snow cover for regional C budgets, biogeochemistry, hydrology, and albedo due to climate change are rudimentary, especially for the High Arctic. In a polar semidesert of NW Greenland, we used a ~10 year old snow manipulation experiment to quantify how deeper snow affects magnitude, seasonality, and <sup>14</sup>C content of summer C emissions. We monitored ecosystem respiration (<italic>R</italic><sub>eco</sub>), soil CO<sub>2</sub>, and their <sup>14</sup>C contents over three summers in vegetated and bare areas. Additional snowpack, elevated soil water content (SWC), and temperature throughout the growing season in vegetated, but not in bare, areas. Daily <italic>R</italic><sub>eco</sub> was positively correlated to temperature, but negatively correlated to SWC; consequently, we found no effect of increased snow on daily flux. Cumulative summertime <italic>R</italic><sub>eco</sub> was not related to annual snowfall, but to water year precipitation (winter snow plus summer rain). Experimentally increased snowpack shortened the growing season length and reduced summertime <italic>R</italic><sub>eco</sub> up to 40%. Soil CO<sub>2</sub> was older under increased snow. However, we found no effect of snow depth on the <italic>R</italic><sub>eco</sub> age because older C emissions were masked by younger CO<sub>2</sub> produced from the litter layer or plant respiration. In the High Arctic, anticipated changes in precipitation regime associated with warming are a key uncertainty for understanding future C cycling. In polar semideserts, water year precipitation is an important driver of summertime <italic>R</italic><sub>eco</sub>. Permafrost C is vulnerable to changes in snowpack, with a deeper snowpack‐promoting decomposition of older soil C.</p> </abstract>