Understanding Impacts of Climate Change on Carbon Cycling by Soil Microbes
Quantifying feedbacks between terrestrial carbon cycling and changing climate conditions remains one of the major sources of uncertainty in predicting climate change impacts. A lack of mechanistic understanding of biogeochemical processes mediated by soil microbes and how they are affected by climate change variables is a significant element of this problem. New ‘omics techniques for high-throughput characterization of microbial community structure and function are now providing powerful tools to examine these processes in intact ecosystems. Researchers at the University of Oklahoma have studied the impacts of long-term warming experiments (10+ years) on soil microbes at a grassland field site. The study describes compositional and functional shifts in the microbial communities related to elevated temperature and resulting changes in overlying vegetation and soil moisture. These effects were correlated with an increase in CO2 efflux from soils, which was tied to stimulation of microbial community members and enzyme activities associated with degradation of labile (but not recalcitrant) soil carbon sources. The team also observed an accelerated microbial cycling of nitrogen, phosphorous, and other soil nutrients that appeared to help stimulate plant growth and at least partially ameliorate the net loss of carbon from the system. These findings point to the complex role of microbial communities in climate impacted ecosystem processes. Further study will be needed to tease apart their net effects on carbon feedbacks.
Zhou, J., K. Xue, J. Xie, Y. Deng, L. Wu, X. Cheng, S. Fei, S. Deng, Z. He, J. D. Van Nostrand, and Y. Luo. 2011. “Microbial Mediation of Carbon-Cycle Feedbacks to Climate Warming,” Nature Climate Change 2, 106-10. DOI: 10.1038/nclimate1331.