EAPSI: The Temperature Sensitivity of Greenhouse-gas Producing Bacteria at High Latitudes

Cagle Grace, Baton Rouge LA

Investigators

Abstract

The study to be conducted in this award will determine how soil bacteria that produce the greenhouse-gas methane are affected by a long-term 1-2°C increase in temperature. This project is a collaboration with the Northeast Institute in Changchun, China, and will build upon a growing knowledge base on the impacts of temperature increase on wetlands working with host researcher Dr. ChangChun Song. The Institute has operated open-top warming chambers, which warm the inside 1-2°C (comparable to what is forecasted for climate change over the coming decades), for almost 10 years. By studying the effects of these chambers, the researcher will determine how a long-term temperature increase impacts different types of bacteria that produce and consume methane. High-latitude wetlands store an enormous amount of carbon that could be released to the atmosphere, and high latitudes are predicted to experience a greater temperature increase than low latitudes in the coming years. However, there is some uncertainty on how methane emissions from northern wetlands will be impacted by a warmer climate due to changes in the methane-producing and methane-consuming patterns of these bacteria. This field-based experiment is a unique opportunity to better understand how greenhouse gas emissions from wetlands will be impacted by climate change. The quantity of methane production in high-latitude wetlands under elevated temperatures is a matter of scientific uncertainty, but relevant to the global carbon cycle. Understanding the fluxes and drivers of greenhouse gas emissions is a goal of the Northeast Institute, which maintains the open top chambers, and monitors greenhouse gas emissions, soil chemical properties, and vegetation parameters. My experiment will utilize the experimental warming chambers, as well as sampling and experimental protocols previously established by the group, to determine the impact of 1-2°C warming on methane-cycling bacterial activity during the summer. The 8-week study will include 1) collecting soil samples from open-top warming chambers operated by the Northeast Institute of Geography and Agroecology of the Chinese Academy of Sciences and 2) analysis of the expression of functional genes involved in microbial production and oxidation of methane using the reverse transcription quantitative polymerase chain reaction (RT-qPCR) technique. Results will help predict future rates of methane emission from high-latitude wetlands that are extremely sensitive to climate change. The data will also further a comparative study on responses of indigenous microbial community to global climate change in the Sanjiang Plain (cold and organic-rich) and Mississippi River Deltaic Plain (warm and organic-rich) wetlands. The results from this study will show how methanogen activity is affected by long term warming under field conditions. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Chinese Ministry of Science and Technology.