Life Science Hour Seminar Series

Name:Frank Stewart
 Microbiology Candidate Seminar
Title:From genes to ecosystems: Microbial consequences of ocean oxygen loss
Date:Friday, 22 February 2019
Time:4:00PM
Location:Murie Life Science Bldg, Murie Auditorium.

Abstract:

I am an environmental microbiologist with broad interests in the dynamics of microbial systems. My research is motivated by the beliefs that microbial systems remain a frontier for natural history and scientific discovery, and that exploring this frontier is necessary and important for understanding biological diversity and its changing role in ecosystem processes. The first major research theme in my lab explores how aquatic microbes respond to environmental change, notably declines in ocean oxygen content. The second major theme explores how life in symbiosis drives microbial evolution and ecology. My research targets diverse systems, from the marine water column to the intestinal microbiomes of fishes. This research aims to identify metabolic properties that underlie the ecology of microbes and microbe-host systems, the evolutionary context under which these functions arose, and the role of these functions in ecosystem-scale processes in a changing environment.

About the Speaker:

Environmental change is reshaping the composition and function of ocean ecosystems. Notably, marine waters with low dissolved oxygen, so-called oxygen minimum zones (OMZs), are predicted to increase in both expanse and frequency in response to climate warming and human modifications of coastal zones. Such shifts have profound consequences for biogeochemical cycles, as OMZs are critical sites for microbially-mediated transformations of carbon, nitrogen, and sulfur, including the cycling of potent greenhouse gases (e.g., N2O, CH4). The integration of genomic analyses with coupled biogeochemical measurements is enhancing our understanding of OMZ microorganisms, revealing a richness of metabolic processes structured along a vertical redox gradient and previously unrecognized linkages between elemental cycles. Recent work by our lab has identified novel clades of OMZ bacteria mediating anaerobic methane and sulfide oxidation coupled to denitrification, as well as previously unrecognized adaptations to anaerobic metabolism by the world's most abundant bacterium. This talk highlights these and other OMZ processes in relationship to key environmental drivers, including water column chemistry and the microscale partitioning of communities between particle-associated and free-living microniches. Coupled omic-biogeochemistry studies are necessary for understanding how oxygen constrains microbial diversity and activity, and consequently for predicting how ocean de-oxygenation will affect ecosystem structure and function under global climate change.

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