Microorganism Adaptation to Climate Change Plays Major Role in Ecosystem Functions, Says CSU Researcher

It is easy to observe that many organisms are well adapted to their local environment, with obvious features such as a polar bear’s thick fur coat in cold environments or a camel's hump that is instrumental to its survival in the dry desert. But it is much more difficult to tell if microorganisms that live in the soil beneath our feet are also uniquely adapted to their environment. In two new studies published in the journal, Biogeochemistry, Colorado State University researchers set out to determine just that.

Scientists’ understanding of the role of microbial adaptation to climate is critical to accurate predictions of ecosystem functions under changing climate, such as the rate of nutrient cycling and the annual growth of plants. Climate models project that precipitation patterns will likely intensify in the future, causing more droughts and floods that are stressful to the microorganisms that drive soil biogeochemical cycling. If microbes are uniquely adapted to their local climate, scientists might expect them to respond to new conditions in different ways, just as an animal with a thick coat of fur might not survive in a tropical climate because it is poorly adapted to that environment.

Matthew Wallenstein, assistant professor in CSU’s Department of Ecosystem Science and Sustainability and research scientist in the Natural Resource Ecology Laboratory, and Sarah Evans, a doctoral candidate at CSU, found that microbes exposed to 10 years of an experimentally intensified precipitation regime were less affected by stressful drying and rewetting in a laboratory experiment than microbes from the non-treated plots. This suggests that microbial communities adapt to climate change over time, affecting their ability to conduct important processes such as decomposition and nutrient cycling.

“Although we found evidence for adaptation in one example, it is currently hard to predict when and where adaptation will affect the rates of ecosystem processes,” Wallenstein said. “However, based on our fundamental understanding of the biology of microbes, we can make some educated guesses of when we might expect to see rapid microbial adaptation. These ideas can help guide the direction of future research.”

In the studies, the research team proposes that measuring the community traits of the microbes instead of their identity – for example, their resistance to rainfall pulses or their ability to function at different temperatures – might be an effective way to study how microbes adapt to climate. Measuring traits may also lead to better understanding of when this climate-induced adaptation might cause microbes to respond differently to new conditions and affect the way ecosystems function.

The full article, “Soil microbial community response to drying and rewetting stress: Does historical precipitation regime matter?” co-authored by Sarah Evans, doctoral candidate at the Natural Resource Ecology Laboratory, is available at http://www.springerlink.com/content/k105v3060806l128/.

The full article, “A trait-based framework for predicting when and where microbial adaptation to climate change will affect ecosystem functioning,” co-authored by Edward Hall, U.S. Geological Survey research biologist and NREL scientist, is available at http://www.springerlink.com/content/977nv7v482788193/.