HR: 1340h
AN: B23D-1613    [Abstracts]
TI: Variation of Ecosystem Respiration with Different Vegetations at Different Microtopographies
AU: Tang, Y
EM: ytang@sunstroke,sdsu.edu
AU: * Oechel, W
EM: ytang@sunstroke.sdsu.edu
AB: Department of Biology, San Diego State University, San Diego, CA 92182, USA Abstract: Arctic tundra is one of the significant stocks of terrestrial soil carbon. With global climate change, it is likely that the distribution of vegetation types was altered at high latitudes. Consequently the ecosystem CO2 emission will be changed with the alteration. To predict the change trend due to global change in the future, it is critical to clarify the variation of CO2 emission from ecosystem to atmosphere at different topographies and vegetation types. In this study, we conducted 16 plots with three different vegetation types: Dry lichen, Sphagnum moss, Carex at five different micro topographies: low center polygon, high center polygon, rim, trough and flat at Barrow, Alaska. Automatic chamber system Licor-8100 and Licor-8150 were applied to observe ecosystem respiration continually from middle June 2007 to the end of August 2007. Soil temperature, soil moisture were measured at the same time. Thaw depth, water table and Normalized Difference Vegetation Index (NDVI) were observed at each plot with a frequency once a week. As a result, the flat area with Carex vegetation was significantly greater than other micro topographies with other vegetations. High center polygons have the lowest ecosystem respiration even with different vegetations. These results suggest that both micro topography and vegetation play key role on the variability of ecosystem CO2 emission. Middle-level water table, high thaw depth, and appropriate NDVI will increase the emission of CO2 from ecosystem to atmosphere. With the season changing, ecosystem respiration increased with higher temperature and lower water table and soil moisture. Key words: ecosystem respiration, microtopography, vegetation type
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting