「Viral dynamics in aquatic systems: Some preliminary findings from the Lake Biwa ecosystem」

Pradeep Ram

Over the last 15 years, our view of aquatic microbial food webs has changed with the discovery of the abundance and activities of viruses. Viruses are the most abundant and, probably, the most diverse biological entities in aquatic systems. They play a significant role in the cycling of nutrients and organic matter through their lysis and at times can match or prevail over grazing by protists as source of mortality for bacteria. However, still little information is known on these biological entities in freshwaters, although some of the fundamental works on viruses are known from these ecosystems. The distribution of viruses has been found to be determined by factors that affect the activity and density of the host populations, mainly bacteria. Lysis of metabolically active bacteria leads to larger retention of nutrients in the water column, which could enhance bacterial respiration and lead to low bacterial growth efficiency estimates. In my talk I would like to focus on the above aspect and present some of the preliminary findings of my study.