Seasonal Dynamics of a Coastal Ecosystem Reveals Distinct Dynamics for Eukaryotes, Prokaryotes and Viral Communities

In the present study we investigated the seasonal community dynamics of eukaryotes, prokaryotes, and Mimiviridae of Uranouchi Inlet, Kochi, Japan. Uranouchi Inlet is enclosed environment with a humid subtropical climate, but heavily contrasting seasons. The inlet is home to several sporadically forming red tides throughout a year, making it a good location to study the dynamics of eukaryotic communities and their relationships with prokaryotes and eukaryote infecting viruses. We performed metabarcoding analyses using 16S, 18S ribosomal RNA gene, and polymerase B (Mimiviridae) gene amplification methods as well as cell count data of 43 seawater samples collected over a time span of 20 months. Previous studies already revealed the seasonality of marine viruses. We were also able to show a pronounced (i.e. monthly) seasonality of Mimiviridae. We observed simultaneously occurring seasonal cycles for the communities of eukaryotes, prokaryotes, and Mimiviridae. Despite this synchronous change of the different communities, we observed community dependent differences in the ASV persistency as well as the ASV recovery.