Bioavailability of Carbon and Iron from Viral Lysis Products

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The investigator will examine the role of viruses in the biogeochemical cycling of iron (Fe) and carbon (C) in marine systems. Viruses are a major cause of prokaryotic mortality, but in spite of many suggestions that they are important in nutrient recycling, only minimal quantitative evaluations of this process exist. Preliminary data demonstrate that viruses can mediate rapid transfers of elements to bacteria and other plankton. As prokaryotic organisms represent the majority of the living biomass in the ocean, viral lysis of autotrophic and heterotrophic prokaryotes represents a little studied source of potentially limiting nutrients to marine organisms. Recent evidence also suggests that the bioavailability of Fe to marine organisms is regulated by the complexation of Fe by uncharacterized organic ligands in seawater. This project will directly measure virus-mediated release of Fe and C from host cells using radioisotope and ultrafiltration techniques, and examine subsequent Fe bioavailability. Field studies in the subtropical Atlantic Ocean and Strait of Georgia (British Columbia) will complement the lab studies by focussing on size-fractionated virus-host community dynamics and Fe/C transfer.