Research

Some Current Projects in the Lab

The projects summarized here are all collaborations with the lab of Grieg Steward, viral and microbial ecologist extraordinaire. 

Drivers and consequences of protist trophic strategies

Many of the unicellular eukaryotes in the sunlit ocean are phago-mixotrophs, meaning that they perform photosynthesis (like autotrophs) and also ingest prey (like predatory heterotrophs). It is important to better understand how the relative frequency of different trophic strategies varies across environmental conditions, what mechanisms drive these patterns, and what the consequences are for ecosystem function. We have been using a large collection of novel isolates to characterize how key functional traits vary across taxa with different strategies, and test whether trophic strategy explains niche differences along major environmental gradients. We have also been developing ecological theory for how trophic strategies in plankton communities emerge from physiological tradeoffs and principles of resource compeition. 

Making sense of virus size

Viruses vary immensely in size, with the largest ʻgiantʻ viruses having genomes a thousandfold larger and virions a millionfold larger than the smallest viruses. Phytoplankton and other single-celled protists are infected by viruses from across this size spectrum, but we donʻt know why such a diverse spectrum of sizes exist, and how the fitness of different sizes varies across environments. We are performing experiments with diverse novel isolates, and developing quantitative models, to start making sense of virus size. 

Unraveling microbial food webs

Single-celled organisms are foundational to productivity and element cycles in the ocean, but we know relatively little about the food web linkages between common taxa in the open ocean. We are using a combination of lab and in situ experiments to better resolve the major predators of the most abundant bacterial lineages.