How Will Global Warming Affect the Soil Carbon-Cycle?

Nearly 70 percent of the organic carbon in terrestrial systems is found in soils. As the planet warms, how will soils and the terrestrial carbon-cycle respond? Daniel H. Buckley and Johannes Lehmann, Integrative Plant Science, say it’s difficult to predict. Changes in atmospheric carbon dioxide, temperature, precipitation, and ecosystem nitrogen inputs will impact the primary production and carbon inputs to soils. The ability to predict carbon-cycle responses, however, remains limited by unexplained variability within the terrestrial carbon-cycle. Buckley and Lehmann, along with researchers from the Lawrence Berkeley National Laboratory, Pacific Northwest National Laboratory, and University of Colorado, Boulder, seek a greater understanding of the biotic mechanisms that govern carbon transformations in soils.

This begins with studying changes in microbial community structure and function and how those changes impact soil processes—a cross-scale examination of microbial contributions to carbon-cycle dynamics and carbon-fate in soils. The team hypothesizes that variation in microbial functional traits constrain and define microbial metabolism in soils. They predict that these functional traits govern the manner in which microorganisms interact with dissolved organic carbon and particulate organic carbon. The researchers expect that a better understanding of these interactions can explain mechanisms of soil carbon stabilization.

The team is investigating these processes using a suite of complementary isotopic techniques and microspatial analysis of soil organic carbon. These techniques will be deployed in experiments designed to test fundamental assumptions that underlie terrestrial carbon-cycle models. The project’s overall goals include describing the functional characteristics of soil microorganisms responsible for major carbon transformations in soil, evaluating the metabolic and ecological interactions that underlie soil carbon-cycle dynamics, and evaluating the degree to which these interactions impact rates of carbon mineralization and stabilization in soils.

Funding Received

$2 Million spanning 3 years