Thursday, October 22, 2015 - 2:00pm
Dr. Sarah Bagby, of both UCSB Earth Science and the Marine Science Institute, will give a talk at this week's Speakers Club entitled "Quantitative geobiology of marine hydrocarbon seeps and spills" at 2:00 PM Thursday in Webb Hall 1100.
The continental margins harbor large reserves of oil and natural gas, which enter marine ecosystems both through natural seeps at the seafloor and through accidental spills from drilling and transport operations. Seafloor seeps are a major source (≥85 Tg/year) of the potent greenhouse gas methane; oil spills can disrupt entire ecosystems and the economies that rely on them. Microbial hydrocarbon biodegradation mitigates these impacts. But seeps and spills are rife with methodological challenges, and a systematic understanding of the factors controlling biodegradation has remained beyond our grasp. I will describe the new approaches I have developed to handle two aspects of this problem. First, I will discuss my work with data gathered in the federal response effort to the Deepwater Horizon disaster. Here, I have developed statistical analyses that shed light on the fate of the ~2 million barrels of oil trapped in the deep ocean, finding both where much of the oil went and how its biodegradation depends on its physical distribution. Second, I will describe the development of novel samplers to probe active microbial metabolism at natural deep-sea hydrocarbon seeps. Using these samplers, we have collected a rich library of parallel geochemical and biological samples from three seep sites over two years. The breadth of these libraries opens many lines of attack in the attempt to understand these dynamic systems—an attempt that has already uncovered an unexpected mode of microbial genetic diversification.
October 20, 2015 - 10:57am