HR: 10:35h
AN: C32A-02    [Abstracts]
TI: A Comparison of Summer and Winter CO2 Fluxes From a Seasonally Snow-Covered High Alpine Meadow at Niwot Ridge, Colorado
AU: * Filippa, G
EM: gianluca.filippa@unito.it
AF: Università degli Studi di Torino DI.VA.P.R.A. - Chimica Agraria e Pedologia, Via Leonardo da Vinci, 44, Grugliasco, TO 10095, Italy
AU: Lipzin, D
EM: liptzin@nature.berkeley.edu
AF: Institute of Arctic and Alpine Research (INSTAAR) University of Colorado, 1560 30th Street, Boulder, CO 80309-0450, United States
AU: Brian, S
EM: seok@Colorado.edu
AF: Institute of Arctic and Alpine Research (INSTAAR) University of Colorado, 1560 30th Street, Boulder, CO 80309-0450, United States
AU: Chowanski, K
EM: kurt.chowanski@colorado.edu
AF: Institute of Arctic and Alpine Research (INSTAAR) University of Colorado, 1560 30th Street, Boulder, CO 80309-0450, United States
AU: Helmig, D
EM: Detlev.Helmig@Colorado.EDU
AF: Institute of Arctic and Alpine Research (INSTAAR) University of Colorado, 1560 30th Street, Boulder, CO 80309-0450, United States
AU: Williams, M W
EM: markw@culter.colorado.edu
AF: Institute of Arctic and Alpine Research (INSTAAR) University of Colorado, 1560 30th Street, Boulder, CO 80309-0450, United States
AU: Freppaz, M
EM: michele.freppaz@unito.it
AF: Università degli Studi di Torino DI.VA.P.R.A. - Chimica Agraria e Pedologia, Via Leonardo da Vinci, 44, Grugliasco, TO 10095, Italy
AU: Zanini, E
EM: ermanno.zanini@unito.it
AF: Università degli Studi di Torino DI.VA.P.R.A. - Chimica Agraria e Pedologia, Via Leonardo da Vinci, 44, Grugliasco, TO 10095, Italy
AB: Studies concerning CO2 emission from soil to the atmosphere are essential to quantify and understand the carbon source or sink strength of ecosystems and to develop a global carbon balance. Seasonally snow-covered subalpine soils have been shown to be a non-negligible source of CO2 even during the winter season. These relatively high wintertime CO2 fluxes are due to the accumulation of the seasonal snowpack, which provides thermal insulation for subnivean soils and therefore allows biological activity during the winter. In high elevation sites in Colorado, such as the one we studied, the snow-covered season can last six months or more and therefore under-snow CO2 production can have a significant contribution to the annual ecosystem respiration. Moreover, at these sites, snowmelt is the main process providing water and solutes to soils, that usually dry out from June to September. In order to compare winter and summer fluxes, we measured CO2 fluxes continuously through the snow at a subalpine meadow in the Rocky Mountains, Colorado, during the winter 2006-2007 and made bi-weekly soil chamber flux measurements during the summer 2007. Ancillary measurements include soil temperature and soil moisture. During the winter, air samples were collected through the snowpack at different depths and fluxes were calculated using Fick's law. In the summer, measurements were done using an open chamber design. While the summer measurements currently are still underway, our first, preliminary data indicate a decreasing trend in CO2 fluxes during the drying-out period from July to September.
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0330 Geochemical cycles (1030)
SC: Cryosphere [C]
MN: 2007 Fall Meeting