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Zhang, Chuanlun

Dr. Chuanlun Zhang

Associate Research Scientist
Savannah River Ecology Laboratory
University of Georgia
Aiken, SC

Crenarchaeota are members of a poorly surveyed grouped of microorganisms in the domain Archaea. This study will focus on the alkalithermophilic Crenarchaeota: those that grow both at or above pH 8 and at or above 60 degrees C. Most of the known thermophilic Crenarchaeota have been found in low pH environments. More alkaline habitats such as these have received less attention. Numerous hot springs located in Nevada are alkaline and may be unique niches for Crenarchaeota. Based on our preliminary observations, the specific objectives of this project will further focus on the alkalithermophilic Crenarchaeota that are chemolithoautotrophic, which means that they obtain their carbon from CO2, and their energy by transforming inorganic substances such as nitrogen, iron, or sulfur.

Specifically, we aim to determine the ecological functions and biogeochemical consequences of CO2 fixation performed by alkalithermophilic Crenarchaeota. Research approaches will include novel culturing techniques, gene sequencing, and integrated lipid biomarker and stable isotope analyses. Short-term kinetic analysis will also be performed using 14C-labeled CO2 or HCO3 for activity measurements under conditions consistent with the in situ environments.

The proposed research, funded by the National Science Foundation, will integrate studies of diversity, physiology, molecular genetics, and biogeochemistry of chemolithoautotrophs, and build a strong link between their diversity and function in carbon metabolism in hot spring environments. Results from this study will enable us to develop ideas and strategies for establishing a future long-term microbial observatory to study total microbial diversity and processes in Nevada hot springs, so that they can be compared to hot springs in other habitats with a different geochemistry, such as those in Yellowstone National Park or the Uzon Caldera in the Kamchatka peninsula. Finally, this project will enhance infrastructure for developing genome-enabled geomicrobiology programs at The University of Georgia’s Savannah River Ecology Laboratory, with strong ties to academic departments on the main campus in Athens, GA. Our collaborative efforts will be directed to train graduate and undergraduate students with interdisciplinary skills for solving complex geomicrobiogical problems in the 21st Century.