Roxanne Beinart

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Research Summary

There is a growing appreciation for the ubiquity of microbial symbioses on earth, yet in most habitats we have only a basic understanding of their physiology and ecology. In many ecosystems, eukaryotes have evolved specific associations with prokaryotes that capitalize on the relative diversity of prokaryotic metabolisms. I am interested in describing and understanding the physiology of symbiotic prokaryotes, with emphasis on their role in mediating interactions with the biotic and abiotic environment, in order to better understand the ecology and biogeochemistry of symbioses.

Symbioses between anaerobic protists and intracellular, methanogenic archaea have been found in many anoxic habitats, however the contribution of symbiont-produced methane to the marine methane cycle is yet unconstrained. Though taxa known to host methanogens in other habitats have been detected in general surveys of protists in O2-poor and anoxic marine water columns, to date, they have never been specifically surveyed, and no studies have quantified their contribution to methane production in these habitats.

To develop our understanding of the details of these partnerships and address their contribution to the methane cycle, I will examine the ecology and physiology of methanogen-protist symbioses in Saanich Inlet (SI), a seasonally anoxic fjord off the coast of British Columbia, Canada that accumulates methane (>1 μM) in its deep water. Working with Dr.’s Virginia Edgcomb and Rebecca Gast, I am pairing surveys of the abundance and diversity of methanogen-hosting protists, with assessments of their metabolism through the experimental measurement of methane production by natural populations and analysis of total symbiont gene content (i.e., genomics). This combination of observational and experimental approaches will provide valuable insight into distribution, physiology and activity of these symbioses.

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