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Oceanography Seminar
Oscar Abraham Sosa
PhD Candidate
WHOI-MIT
Joint Program in Biological Oceanography
"Screening Marine Microbial Communities for Bacterial
Degraders of Dissolved Organic Matter"
Marine dissolved organic matter (DOM) is considered a fundamental substrate in
the biogeochemistry and ecology of the ocean because it sustains great part of
bacterial life in the sea. Bacteria, in the process of consuming and decomposing
marine organic matter, return carbon dioxide (through respiration) and inorganic
nutrients to the water column making them key regulators of the cycles of carbon
and of marine productivity. Yet we know very few details of how bacteria catalyze
the decomposition of DOM and the types of metabolism that this process supports.
My thesis project aims to identify suitable bacterial systems to study the process of
DOM degradation in the laboratory. In a recent experiment aimed to screen a
coastal environment for bacterial DOM degraders, the addition of high-molecularweight DOM to seawater cultures resulted in an enrichment of bacteria specialized
in degrading single-carbon compounds like methanol (methylotrophic) and of
bacteria closely related to polysaccharide-degrading strains. It is expected that the
microorganisms identified through this work will serve as models systems to study
in depth the genetic determinants and biochemical transformations that drive the
cycling of DOM in the ocean.
Thursday
November 13, 2014 3:00 p.m.
MSB 100