Soil moisture feedback mediates increased carbon storage under elevated CO{sub 2}
- Univ. of California, Berkeley, CA (United States)
- Univ. of Texas, Austin, TX (United States); and others
After 3 years of exposure to elevated atmospheric CO{sub 2}, soil carbon increased in an extremely nutrient-limited serpentine grassland, but did not change in a more productive sandstone grassland. The increase in the serpentine shows the potential for nutrient-limited ecosystems to sequester carbon under elevated CO{sub 2}, but lack of response in the sandstone grassland suggests that increased soil carbon is not a general ecosystem response to elevated CO{sub 2}. Changes in soil moisture under elevated CO{sub 2} may explain the lack of response in the sandstone. Elevated CO{sub 2} decreases transpiration in plants from both ecosystems, but this consistently increases soil moisture only on the sandstone, where plants more strongly control evapotranspiration than on the serpentine. Increased soil moisture stimulates decomposition in these systems, potentially compensating for increased carbon input to soil under elevated CO{sub 2}, resulting in no net change in soil carbon. Increased soil moisture also stimulates plant growth directly and stimulates nitrogen mineralization and plant nitrogen uptake, potentially increasing plant production under elevated CO{sub 2}. We suggest that, in ecosystems with well developed plant canopies where increased soil moisture is likely under elevated CO{sub 2}, feedbacks through soil moisture may increase production, but may also constrain increased carbon storage in soil.
- OSTI ID:
- 107107
- Report Number(s):
- CONF-9507129-; ISSN 0012-9623; TRN: 95:006512-0023
- Journal Information:
- Bulletin of the Ecological Society of America, Vol. 76, Issue 3; Conference: 80. anniversary of the transdisciplinary nature of ecology, Snowbird, UT (United States), 30 Jul - 3 Aug 1995; Other Information: PBD: Sep 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Root responses to elevated CO2, warming and irrigation in a semi-arid grassland: Integrating biomass, length and life span in a 5-year field experiment
Plant species mediate changes in soil microbial N in response to elevated CO{sub 2}