B098-02
The Means of Production: Carbon fixation and assimilation in an ultrabasic, serpentinization-influenced aquifer
Tuesday, 15 December 2020: 05:34
Virtual
Lauren Marie Seyler1, William J Brazelton2, Craig McLean3, Lindsay I Putman4, Alex Hyer5, Michael D. Kubo6, Tori M Hoehler6, Dawn Cardace7 and Matthew O Schrenk4, (1)Stockton University, Biology Program, Galloway, NJ, United States, (2)University of Utah, School of Biological Sciences, Salt Lake City, UT, United States, (3)Woods Hole Oceanographic Institution, Woods Hole, United States, (4)Michigan State University, Department of Earth and Environmental Sciences, East Lansing, MI, United States, (5)University of Utah, Department of Biology, Salt Lake City, UT, United States, (6)NASA Ames Research Center, Moffett Field, CA, United States, (7)University of Rhode Island, Department of Geosciences, Narragansett, RI, United States
Abstract:
Serpentinites are known to support microbial communities that feed off of the products of serpentinization (e.g. formate, methane, H
2 gas), while adapted to harsh environmental conditions such as high pH and low dissolved inorganic carbon (DIC) availability. However, the biochemistry of microbial populations that inhabit these environments is understudied and complicated by overlapping biotic and abiotic processes. The aim of this study was to identify potential sources of carbon and methods of primary production in an environment that is depleted of soluble inorganic carbon, to characterize the flow of metabolites within the microbial communities in this environment, and to describe overlapping biogenic and abiogenic processes impacting carbon cycling in serpentinizing rock.
We applied metagenomics, metatransciptomics, and metabolomics techniques to environmental biomass samples taken from the Coast Range Ophiolite Microbial Observatory (CROMO), a subsurface observatory consisting of a series of twelve wells drilled into an actively serpentinizing ophiolite in the California Coast Range. DNA and RNA sequence data from the CROMO wells suggests that acetogenesis via the Wood-Ljungdahl pathway, the Calvin-Benson-Bassham cycle, the reverse tricarboxylic acid cycle, and methylotrophy are key pathways of carbon fixation and assimilation in the microbial communities at CROMO. Putative identification of several intermediate metabolites involved in these processes supports this hypothesis. The dissimilatory oxidation of formaldehyde by methylotrophs may provide formate and CO2 to acetogens, thus mitigating conditions of limiting DIC. Our results are promising regarding the future use of metabolomics techniques in this and other serpentinizing environments, for the identification of biomarkers and metabolic pathways.
