Elevated CO2 has been shown to increase plant biomass and the influx of carbon below ground, which can increase the rates of respiration from roots and soil microbes (Schlessinger and Andrews 2000). This increase in CO2 flux from soils will limit the amount of carbon stored within soils (Schlessinger and Lichter 2001). The magnitude of the increase in respiration rates, however, varies due to differences in microbial communities, availability of carbon resources, and rates of plant growth. Areas experiencing significant increases in net primary production (NPP) have been found to still be important carbon sinks despite increases in soil respiration (Sullivan et al. 2008).
Schlessinger W.H. and J.A. Andrews. 2000. Soil respiration and the global carbon cycle. Biogeochemistry. 48: 7-20.
Schlessinger W.H. and J. Lichter. 2001. Limited carbon storage in soil and litter of experimental forest plots under increased atmospheric CO2. Nature. 411: 466-469.
Sullivan B.W., T.E. Kolb, S.C. Hart, J.P. Kaye, S.Dore, and M. Montes-Helu. 2008. Thinning reduces soil carbon dioxide but not methane flux from southwestern USA ponderosa pine forests. Forest Ecology and Management. 255: 4047-4055.
