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Rates and radiocarbon content of summer ecosystem respiration in response to long‐term deeper snow in the High Arctic of NW Greenland
Author(s) -
Lupascu M.,
Welker J. M.,
Xu X.,
Czimczik C. I.
Publication year - 2014
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2013jg002494
Subject(s) - snowpack , snow , environmental science , snowmelt , growing season , arctic , ecosystem , precipitation , permafrost , atmospheric sciences , soil respiration , climatology , soil water , hydrology (agriculture) , ecology , oceanography , geography , geology , soil science , geotechnical engineering , meteorology , biology
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 14 C content of summer C emissions. We monitored ecosystem respiration ( R eco ), soil CO 2 , and their 14 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 R eco was positively correlated to temperature, but negatively correlated to SWC; consequently, we found no effect of increased snow on daily flux. Cumulative summertime R eco 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 R eco up to 40%. Soil CO 2 was older under increased snow. However, we found no effect of snow depth on the R eco age because older C emissions were masked by younger CO 2 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 R eco . Permafrost C is vulnerable to changes in snowpack, with a deeper snowpack‐promoting decomposition of older soil C.