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.