Abstract
The polar regions are rapidly undergoing major climate change-related physicochemical transformation with consequences for the marine ecosystems. Microorganisms (phytoplankton and bacteria) represent the vast majority of the living marine biomass, form the base of the food web, and are essential for global biogeochemical cycling. Our preliminary results show that polar marine viruses, mostly infecting these numerically dominant microorganisms, lyse their different hosts at rates comparable to grazing (which was previously thought to be the dominant microbial loss factor), but their identity is largely unknown. Climate change-induced shifts in the microbial community can be expected to alter viral control both quantitatively (share) and qualitatively (host species succession), with subsequent effects on energy and matter flow through the entire polar food web. The overall aim of this project is to elucidate the thus far hardly studied polar marine viral diversity, and relate viral diversity to the activity and host range of viruses. Using state-of-the-art viral metagenomics sequencing, the seasonal dynamics of viral phylotypes in both Antarctic and high Arctic polar waters will be explored and compared. Moreover, particle-sorting coupled to metagenomics of sorted clusters, and viral lysis measurements will reveal the viral diversity of infected phytoplankton clusters and allow us to interpret virus-host relationships with high specificity. Together, our project will reveal much-needed knowledge about the viruses that drive biodiversity and microbial turnover in both the polar seas.
Netherlands