Abstract

Viruses are key players in the functioning of microbial food webs, affect all biogeochemical cycles, can manipulate microbial metabolisms, and each infection has the potential to introduce new genetic information into the cell or progeny viruses, thereby driving genetic remodeling of both host and viral populations. Hence, viruses are considered the largest reservoir of genetic diversity. In recent years, the improvement in methods for counting viral abundance and the use of molecular tools to study their diversity have allowed progress in understanding the ecology and spatial distribution of viruses in the ocean. However, there is a lack of knowledge about the temporal patterns of viral abundance, diversity and the impact on their hosts (virus-host interactions) in the sea. Indeed, to perform these studies, it is necessary the availability of time series where these variables are considered together with other biotic and abiotic environmental parameters. Since 2001, there has been a continuous monthly monitoring of microbial abundances, diversity and biogeochemical functions in the Blanes Bay Microbial Observatory (BBMO, Catalan coast), constituting an ideal time-series for the present proposal. The main goal of the DIVAS project is to detect, within the context of the BBMO time series, the existence of recurrent seasonal and interannual patterns in viral abundance, viral diversity and virus-host interactions. Furthermore, we will investigate how these temporal trends are shaped by biotic (abundance of viruses, prokaryotes and protists, together with their diversity and activity) and abiotic parameters (light, temperature, salinity and nutrients), some of them indicators of climate change. We will also identify specific viruses infecting dominant prokaryotic and picoeukaryotic species using single cell genomics. The relative abundance over time of specific viruses will be investigated in environmental sequencing datasets (metaviromes and metagenomes). The metaviromes (≤0.2 μm size fraction) are expected to have free viruses, mostly bacteriophages, while the metagenomes (0.2-3 μm) would include larger free viruses (mostly infecting eukaryotes) and viruses within bacterial and picoeukaryotic cells. Finally, we will evaluate the temporal links of planktonic viruses with abiotic and biotic parameters, how these affect and shape viral abundance community structure and virus-host interactions, and whether there is a hint relating viral ecology and climate change.

Dolors Vaqué

Staff scientist

Ramon Massana

Staff scientist

I am microbial ecologists with a deep interest in protist ecology and evolution