Seascape genomics of Southern Ocean diatoms

Description: Southern Ocean diatom communities are an integral component of short, efficient marine food webs and contribute greatly to deep-sea carbon export. These critical functions are tied to this community's ability to adapt to rapid environmental change, which itself is strongly connected to current levels of within-species genetic diversity. I will present some of my dissertation research into the genetic diversity and population structure of the sea-ice related diatom Actinocyclus actinochilus, with the aim of clarifying how local environmental conditions and massive surface currents can shape phytoplankton genetic structure and gene flow. We used a combination of long- and short-read sequencing to build an annotated reference genome for this taxon and then applied it to assess genome-wide variation across 30 recently collected field isolates from environmentally distinct and spatially distant SO localities. Our preliminary analyses found minimal population subdivision and no correspondence between genetic similarity and environmental or geographic distance. These results suggest a prominent role for circumpolar surface water connectivity as a driver of genetic diversity patterns for plankton in the high latitude SO.

Target Audience: This talk is targeted to a somewhat specialized audience, including those with particular interests in phytoplankton, population genomics and the evolutionary potential of polar microbes.