October 30, 2014
Dr. Sean Jungbluth, University of Hawaii
Aging mid-ocean ridge flanks support a distinct microbial ecosystem
The upper igneous ocean basement is massive and likely to be one of the most habitable subsurface environments due to the porosity and extensive hydrothermal circulation; however, uncontaminated access to this environment is a challenge that has hindered microbiological investigations. Three generations of sampling and instrumentation platforms known as Circulation Obviation Retrofit Kit (CORK) observatories affixed to Ocean Drilling Program (ODP) and Integrated Ocean Drilling Program (IODP) boreholes are providing access to chemically-reducing fluids originating from 1.2-3.5 million-years (Myr) old basaltic crust of the eastern flank of the Juan de Fuca Ridge. Consistent and reliable access to pristine fluids from the ocean crust is due to improvements to CORK observatories, through incorporation of microbiologically-friendly materials, and fluid sampling techniques and equipment. Snapshots of basement fluid microbial diversity and community structure using ribosomal RNA (rRNA) gene sequencing has revealed a basaltic crust microbial community that is distinct from sediments and seawater. Active work seeks to characterize the metabolic potential and genomic features of microbes residing in this region of the ocean crust. These results and a discussion of the general implications of this work will be provided.
Sean received his BS in Bacteriology and Biology from University of Wisconsin at Madison in 2007 and recently completed his PhD in Oceanography from University of Hawaii at Manoa. He has been a C-DEBI Graduate Research Fellow since 2012 and is currently a postdoctoral scholar working to complete ongoing projects and data analyses remaining from his dissertation work. His work focuses on microbial ecology of subseafloor basement fluids, but he is broadly interested in using molecular biology, single-cell and community genomics, microbial culturing, bioinformatics, and oceanographic tools together in an effort to understand the nature of the deep biosphere and its role in global biogeochemical cycles.