Seminar: Emily Zakem

Thursday, March 11, 2021 - 12:00pm

Emily Zakem

Simons Foundation Postdoctoral Fellow, University of Southern California

Linking microbes and climate:
Redox-informed metabolic biogeography and a unified theory for organic matter accumulation

Microbial activity mediates global biogeochemical cycling, including the atmospheric fluxes of climatically relevant gases. I aim to understand the activity and biogeochemical impact of microorganisms from underlying chemical and physical constraints. For example, the key redox chemistry underlying a metabolism can be used to constrain parameterizations of diverse microbial metabolisms in biogeochemical models.

With this approach, the presence or absence of each metabolism emerges dynamically from ecological interactions, potentially expanding model applicability to diverse and unobserved environments. However, the cycling of organic matter involves additional complexity. Seemingly competing hypotheses have been proposed to explain organic matter accumulation. Using a mechanistic model, I have developed a new theoretical framework that explains how organic matter predictably accumulates due to biochemical, ecological, and environmental factors, which subsumes previous hypotheses. The framework derives from the ecological dynamics of microorganisms, the dominant consumers of organic matter.

Emily Zakem is a Simons Foundation Postdoctoral Fellow in Marine Microbial Ecology at the University of Southern California in Los Angeles. She completed her Ph.D. in Climate Physics and Chemistry in the Department of Earth, Atmospheric and Planetary Sciences at MIT. She aims to improve our understanding of the connections between microbial ecosystems, global biogeochemistry, and the climate system. She uses theory and mathematical models to understand how microbial ecology drives carbon, nitrogen, and other elemental cycling. She develops broadly applicable models of microbial populations, grounded in underlying chemical and physical constraints, in order to robustly predict the biogeochemistry of past, present, and future environments.

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