| Isotopic indicators of CO2 and H2O fluxes in semi-arid ecosystems
|
Description:
We are developing isotopic approaches for characterizing biosphere-atmosphere interactions in semi-arid regions. Our efforts potentially will yield new insights into how semi-arid ecosystems respond to variations in climate and land-use. Preliminary data collected in a grass/mesquite dominated ecosystem during the peak of the summer ‘monsoon’ in August, 1998 shows that approximately 60% of night time respiration was derived from carbon fixed by C4 plants despite that more than half of the cover at the site was dominated by shrubby C3 vegetation. The night time respiration signal shifted towards C3 sources by early October after a period of little rainfall and diminished grass activity. Our results demonstrate the potential for tracking C3 and C4 metabolic responses of ecosystems, and potentially whole semi-arid basins, to seasonal climate variations. We are refining our techniques for sampling and analyzing the isotopic composition of water vapor for distinguishing sources of evapotranspiration in these ecosystems.
| College/School:
College of Agriculture | Department/Unit/Center:
School of Renewable Natural Resources |
Investigator(s):
David Williams (dgw@ag.arizona.edu)
Guanghui Lin (glin@bio2.edu)
Brunel Jean-Pierre |
Start date:
1998 | Duration:
One to two years | Total funding:
$20000 | Project status:
ongoing |
Funding source:
University of Arizona/Biosphere 2 |
Research areas:
biology; botany; ecology; hydrology; supply |
