Nowhere are the effects of climate change more evident than at the poles of our planet. The polar marine microorganisms (bacteria and phytoplankton) play vital roles in the global cycling of important elements and form the base of the polar food web.
Our preliminary results show that viruses kill Antarctic phytoplankton at rates comparable to grazing (which was previously thought to be the dominant microbial loss factor), revealing viral killing as a thus far underestimated process affecting all polar phytoplankton groups. Although viruses appear to be an active and integral part of polar ecology, they are still largely uncharacterized.
To know the identity of the viruses infecting the ecologically relevant microbial groups is critical to ultimately developing predictive models and preparing for living on a changing planet. Climate change-induced shifts in microbial species composition and their specific viruses can be expected to affect nutrient and energy flux, and therewith ecosystem functioning. New technological developments that combine the expertise of each of the collaborators in our research group allow us to obtain new insights into the diversity and temporal dynamics of viruses in Antarctic and Arctic waters, and relate our findings to viral lysis rates and host community dynamics. For example, the combination of sorting specific clusters of infected primary producers directly from seawater with (meta)genomic analysis allows us to identify, to our knowledge for the first time, polar host-specific viral phylotypes. Together, this very timely project will unravel the evolution, ecology, and biology of polar marine viruses and their hosts.