Coupling temporal variations in geochemistry to activities of microbial populations in the deep subseafloor biosphere
EMSL Project ID
25599
Abstract
To date, studies of the oceanic subsurface biosphere have effectively demonstrated the existence of an active microbial community, and have begun to characterize community density and distribution via molecular phylogenetic analyses (Edwards et al. 2005; Huber et al. 2006; Sogin et al. 2006). These data are being correlated to bulk fluid geochemistry to constrain the suite of possible metabolisms, although this approach offers limited spatial and temporal resolution. Understanding the physiological potential of this community requires finer scale sampling that avoids contamination that can occur during sampling (e.g. drilling), and coupling genomic analyses with a better measure of metabolic activity (e.g. transcriptomic or proteomic analyses). Accordingly, we have developed a microbial sampler to be deployed in IODP boreholes in order to collect fluid samples over time with the intention of conducting proteomic analyses in collaboration with the EMSL. In particular, we propose to conduct a two year study to look at temporal changes in protein expression in microbial communities recovered from the IODP hole 1026 (near the Juan de Fuca ridge system). The proposed research will have two outcomes; it will provide the first glimpse into protein expression in the deep subsurface, and it will allow us to determine the instrument's limits of temporal resolution (e.g. one week vs. one month, depending on quantities of microbes sampled). We will conduct Quantitative PCR analyses to determine the abundances of the most dominant organisms in collected fluids, and sequence appropriate fosmids (with 16s rRNA genes) to provide nucleotide information for interrogating MS-derived peptide sequences. Most importantly, our approach offers the first-ever glimpse into temporal changes in microbial community and coupled geochemistry in the deep subsurface. This affords us the opportunity to connect in situ geochemistry to microbial activity in this vast biosphere, with high resolution, over time. The resulting data will also be of use to the entire scientific community, making it possible to improve cultivation efforts, constrain metabolic activity, and better model the interactions between biotic and abiotic processes. This is a standard-access, general-type, non-proprietary proposal in response to the 2007 Science Themes Call: Geochemistry/Biogeochemistry and Subsurface Science.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-07-01
End Date
2010-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members