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Joshua S. Weitz Joshua S. Weitz, Ph.D.

Associate Professor
School of Biology
Georgia Institute of Technology


Project: Quantifying the Interplay between Parasites and Predators in the North Pacific Ocean

Marine viruses affect microbial community structure and biogeochemical cycles in multiple ways, including (1) negatively affecting, and potentially limiting, the density of target populations; (2) modifying the metabolic activity of infected cells, including nutrient uptake rates; (3) stimulating production via the "viral shunt", in which cellular lysates are released back into the environment and then re-assimilated by non-targeted cells. Yet inferring the relative importance of virus-induced modifications of microbes and microbial cell fate is difficult in the face of competing ocean processes, e.g., grazing by zooplankton.

In this collaborative effort, we will utilize data-driven modeling approaches to characterize the ecological roles of viruses in the North Pacific Subtropical Gyre. We will combine theoretical and computational analyses of complex marine food and parasites webs to assess how variation in the strength of cellular-scale mechanisms could modify community-scale properties. In parallel, we will utilize inverse modeling approaches to infer the strength of virus-induced effects on microbial communities. Results developed here will enable the incorporation of parameterized models of virus-host interactions into regional models of the ocean ecology of the North Pacific.


Joshua Weitz is an Associate Professor of Biology at the Georgia Institute of Technology where he holds an adjunct appointment in Physics. He received his A.B. in Physics from Princeton University in 1997 and his Ph.D. in Physics from the Massachusetts Institute of Technology in 2003. He was a NSF Postdoctoral Fellow in Interdisciplinary Informatics in the Department of Ecology and Evolutionary Biology at Princeton University. He joined Georgia Tech in 2007 where he directs a multidisciplinary research group focused on the ecology and evolution of viruses that infect microbes. Joshua and his group develop theoretical and computational methods to characterize who infects whom, quantify the effect of viruses on target cells, and predict how interactions with viruses structure microbial communities and ecosystems.