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Project Progress

Members of our team at University of Rhode Island (URI) focus on studies of subsurface metabolic activities and biogeochemical fluxes. To further these studies, team members are developing new techniques to study the activity and physiology of energy-limited microbial communities. For example, Bruno Soffientino and Arthur Spivack are working to develop a robust tritium-based method for quantifying metabolic activity at rates that are well below the detection limit of current radiotracer techniques. Other activities include exploratory work on a novel cell extraction method (Kristofer Carlson, Soffientino, David Smith), development of a numerical model to quantify biogeochemical reaction rates at depth (Scott Rutherford, Uri Manor, Guizhi Wang, Steven D’Hondt, and Spivack), analyses of ATP concentrations and dissolved organic compounds in deep subseafloor sediments (Smith, Beverly Chen, Colleen Mouw), and quantification of biogeochemical fluxes and thermodynamic equilibria of biogeochemical reactions (Spivack, Wang, D’Hondt).

Members of our team at University of North Carolina (UNC) Chapel Hill (Andreas Teske, Antje Lauer, Ketil Sørensen, Mark Lever, Karen Lloyd) focus on genetic analyses of subseafloor communities, with a particular emphasis on organic-poor open ocean sediments. These analyses have required development of DNA isolation procedures for geologically complex low-biomass samples. They are positioned near the sensitivity limit for nucleic acid procedures. Lauer, Teske and Sørensen analyzed archaeal communities from subseafloor sediments with the lowest biomass that have been studied to date. Lever and Teske are undertaking functional gene analyses to determine the principal community members associated with specific subseafloor biogeochemical processes. With collaborator Virginia Edgcomb, Teske also explored the environmental stress tolerance of hyperthermophilic vent archaea.

Members of our team at Woods Hole Oceanographic Institution (WHOI) principally focus on organic biogeochemical and isotopic signatures of life in subsurface environments. Kai Hinrichs, Helen Sturt, Kristin Smith, and collaborator Roger Summons, are using analyses of intact polar lipids to identify active prokaryotes at levels of species to orders. Studies by Hinrichs and collaborators are developing an understanding of a ubiquitous, but previously unknown, process, the biological production of ethane and propane in marine sediments. Hayes, Sean Sylva, Sturt, Summons, and Bradley are using organic and isotopic biogeochemistry to document community composition and metabolic structure of the ecosystem in the Lost City Hydrothermal Field. With collaborator Rothman, Hayes and Summons are using isotopic signatures and biogeochemical modeling to improve understanding of the Neoproterozoic carbon cycle.