Title Snow distribution, soil temperature and late winter CO2 efflux from soils near the Arctic tree line in northwest Alaska
Author Sullivan, P.F.
Author Affil Sullivan, P.F., University of Alaska, Environment and Natural Resources Institute, Anchorage, AK
Source Biogeochemistry (Dordrecht), 99(1-3), p.65-77, . Publisher: Springer, Dordrecht - Boston - Lancaster, International. ISSN: 0168- 2563
Publication Date July 2010
Notes In English. 57 refs. GeoRef Acc. No: 310432
Index Terms precipitation (meteorology); climate; computer applications; ecology; ecosystems; forest tundra; geochemical cycles; geochemistry; hydrogeochemistry; snow; snowfall; soils; soil chemistry; soil temperature; statistical analysis; temperature; tundra; United States--Alaska; Arctic region; Agashashok River; Alaska; atmospheric precipitation; biochemistry; carbon; carbon cycle; carbon dioxide; data processing; depth; forests; geochemical cycle; hydrochemistry; Noatak National Preserve; northwestern Alaska; respiration; seasonal variations; tree line; United States
Abstract The Arctic treeline is advancing in many areas and changes in carbon (C) cycling are anticipated. Differences in CO2 exchange between adjacent forest and tundra are not well known and contrasting conclusions have been drawn about the effects of forest advance on ecosystem C stocks. Measurements of CO2 exchange in tundra and adjacent forest showed the forest was a greater C sink during the growing season in northern Canada. There is, however, reason to expect that forests lose more C than tundra during the wintertime, as forests may accumulate and retain more snow. Deeper snow insulates the soil and warmer soils should lead to greater rates of belowground respiration and CO2 efflux. In this study, I tested the hypotheses that forests maintain a deeper snowpack, have warmer soils and lose more C during winter than adjacent tundra near the Arctic treeline in northwest Alaska. Measurements of snow depth, soil temperature and CO2 efflux were made at five forest and two treeline sites in late winter of three consecutive years. Snow depth and soil temperature were greater in forest than treeline sites, particularly in years with higher snowfall. There was a close exponential correlation between soil temperature and CO2 efflux across sites and years. The temperature-efflux model was driven using hourly soil temperatures from all the sites to provide a first approximation of the difference in winter C loss between treeline and forest sites. Results showed that greater wintertime C loss from forests could offset greater summertime C gain. Copyright 2009 Springer Science+Business Media B.V.
URL http://hdl.handle.net/10.1007/s10533-009-9390-0
Publication Type journal article
Record ID 65007165