Awardee: Douglas E. LaRowe (University of Southern California)
Current Placement: Associate Research Professor, University of Southern California
Degree: Ph.D. Earth and Planetary Science, University of California, Berkeley (2005)
Advisor: Jan P. Amend (University of Southern California)
Amount: $120,000.00
Award Dates: April 1, 2012 — March 31, 2014

Abstract

The goal of this postdoctoral fellowship was to quantify the types and amounts energy that are available to microorganisms in the subsurface, with particular emphasis on the main C-DEBI Focus Study Sites. Not only has this objective been achieved, but a number of related research activities have also been undertaken throughout and beyond the funding period (April 1, 2012 – March 31/2014). Published research directly related to the proposed research goal includes quantitative analyses of the energy available to microorganisms in sediments located near the Juan de Fuca ridge, South Pacific Gyre, Peru Margin (LaRowe and Amend, 2014), deep Guaymas Basin (Teske et al., 2014) and Cape Basin (southeastern Atlantic) (Hernández-Sánchez et al., 2014) and crustal fluids from the Juan de Fuca Ridge (Robador et al., 2015). In closely related work, a model linking the energetics and rates of microbially catalyzed reactions in low-energy environments has been applied to calculate the rates of microbial activity in a hydrothermal vent chimney wall (LaRowe et al., 2014). In a related project, a quantitative relationship between rates of microbial catalysis, energy supply and demand and population size has been developed that complements the limited biogeochemical data describing subsurface environments has been published (LaRowe andAmend, 2015). In addition, collaborations with several other C-DEBI-funded scientists has results in a series of review papers concerning rates of microbial activity in the deep biosphere (Orcutt et al., 2013), an overview and catalogue of IODP sampling that has resulted in microbiological sampling (Orcutt et al., 2014) and a summary of extreme life research that has resulted from the last decade of IODP-sponsored activities (Takai et al., 2014). Furthermore, several ongoing projects are focused on the bioenergetics of shallow Guaymas Basin sediments (McKay et al.), and diffuse hydrothermal fluids emanating from the Loihi seamount (Sylvan et al.). In addition to the research summarized above, the results of a number of other scientific endeavors concerning themes related to C-DEBI goals have also been published. These include a review and synthesis of the energetics of organic synthesis inside and outside of cells (Amend et al., 2013), the possibility of anaerobic oxidation of methane on ancient Mars (Marlow et al., 2014), chemolithotrophy in the continental deep subsurface (Osburn et al., 2014) and the geochemistry and bioenergetic potential of a shallow-sea hydrothermal vent system (Price et al., 2015). Along with these papers, several more have been published concerning the fate or organic matter. In particular, peer-reviewed publications on the anthropogenic perturbation of carbon from land to ocean (Regnier et al., 2013) and a review and synthesis paper on the degradation of organic carbon in marine sediments (Arndt et al., 2013). Furthermore, several more projects related to quantifying the microbial degradation of organic carbon in marine sediments on a global scale are underway.

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