Monday, October 29, 2018

MEB Seminar Series | Nathan Walworth, Ph.D.

Nathan Walworth, Ph.D.
Postdoctoral Researcher, USC, BISC
Prof. Naomi Levine’s Lab

Hitting a moving target: Microbial evolution in a dynamic ocean

Tuesday, October 30, 2018
12 PM
AHF 153 (Torrey Webb Room)

Abstract: Microbes drive global biogeochemistry yet little is known about their microevolutionary rates and processes in response to global change. This is particularly critical in marine systems where long-term trends (e.g. warming) are overlain onto short timescale variability (e.g. eddies) and where advection moves organisms rapidly between ecoregions. The interplay between physical and evolutionary timescales was investigated using a model of adaptation coupled with an eddy-resolving climate model. Fitness increases were encoded by epigenetic modifications under short exposure times to new environments, with beneficial genetic mutations only contributing after extended exposure times. The relationship between microevolutionary and physical timescales is critical for determining future adaptation where assuming instant adaptation may bias model predictions of microbial dynamics. Decoupling between locations of selective pressure and regions of accumulation for adapted individuals was observed. These accumulation zones may act as ‘seed banks’ for novel genotypes and thus evolutionary hotspots under global change.

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