Seasonality of infection:
Dynamics of cyanophage abundances and infection of their hosts
Marine cyanobacteria are photosynthetic bacteria that are estimated to be responsible for a quarter of the ocean net primary production and are highly abundant. Their geographical distribution is shaped by environmental parameters such as temperature, nutrient availability, light intensity but also by presence of mortality agents such as grazers and viruses. This work looks into how seasonal changes in the environmental conditions affects viral abundances and infection patterns of their cyanobacterial host in two different oceanic regions. Analysis of two years of monthly sampling from in the Sargasso Sea, North Atlantic Ocean, a nutrient poor open ocean system, revealed strong re-occurring seasonality for both cyanobacteria and their viruses, with higher abundance and infection in the fall. In sub-Antarctic waters in the South Pacific Ocean, a high nutrient low chlorophyll region, I observed overall similar abundance of cyanobacteria and their viruses but with different taxon-specific composition and higher surface infection. Gaining insight into the drivers of infection dynamics among primary producers will enhance our understanding and predictability of the fate of photosynthetically fixed atmospheric CO2 and ocean biogeochemistry, particularly as our oceans continue to warm.
