The molecular ecology of phytoplankton and their viruses

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As the major primary producers in aquatic environments, phytoplankton play a fundamental role in aquatic food webs and influence global chemical cycles. Besides nourishing the vast majority of aquatic life, phytoplankton remove carbon dioxide from the atmosphere by converting it into organic carbon; a significant portion of the organic material produced by marine phytoplankton sinks out of the surface waters into the deep ocean where it remains isolated from the atmosphere for hundreds, or thousands of years. The discovery that viruses are abundant in aquatic environments, and that many phytoplankton species are susceptible to virus infection suggests that viruses are an important source of phytoplankton mortality that may influence aquatic food webs and global chemical cycles. Despite the growing scientific interest in aquatic viruses, empirical data directly demonstrating the effects of viruses on phytoplankton populations and communities is extremely limited. Therefore, the long-term objectives of my research are to determine if aspects of phytoplankton-virus ecology are predictable, and if the effects of viruses need to be included in models of primary production and phytoplankton ecology. These long-term objectives will be accomplished by working towards four specific objectives that focus on poorly described, but critical topics in phytoplankton-virus ecology. The specific objectives are: 1) to determine the biodiversity and seasonal dynamics of phytoplankton viruses in different freshwater environments, 2) to quantify the relative importance of viruses to phytoplankton mortality, 3) to determine if viruses influence phytoplankton competition, and 4) to determine if environmental conditions influence phytoplankton susceptibility and resistance to virus infection. Ultimately, this work will develop and promote advanced research technologies for aquatic microbiology, and will increase our understanding the role of phytoplankton in global chemical cycles by enabling more accurate, realistic models of phytoplankton ecology and aquatic primary production.