Viral Abundance, Production and Diversity During the North Atlantic Spring Bloom (NASB 2005)

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During the North Atlantic spring bloom of 2005 (NASB 2005), investigators supported by the NSF and the European Union CarboOcean project will address questions about the impact of pCO2 levels and temperature on algal community structure and biogeochemistry. Although phytoplankton vary greatly during the North Atlantic spring bloom, no quantitative information is available on the interactions between this community and native viral populations. The investigators will join the NASB 2005 effort and will 1) examine viral abundance, production and diversity in shipboard experiments, and 2) quantify cyanophage and a major group of viruses infecting eukaryotic algae (the Phycodnaviridae) during transects through waters dominated by cyanobacteria or eukaryotic phytoplankton. The information collected during this study will be critical to understanding the role of viruses during the NASB 2005 event. The investigators will also examine the influence of changes in system trophic status and diversity on changes in virus abundance, production and diversity. They will work with NASB 2005 collaborators to determine how changes in pCO2 and temperature (based on predicted conditions in the year 2100) will impact virus parameters. Their working hypotheses are that viral abundance, production and diversity will vary with system trophic status, with phytoplankton population diversity, and during simulated global climate change conditions. To test these hypotheses, quantitative PCR will be combined with a dilution approach to estimating virus abundance and production, with TEM analysis of samples collected from study sites and with high throughput sequencing of cyanophage and Phycodnaviridae specific targets. The resulting information will provide insight into virus diversity and activity in the region as well as supply the viral component of the microbial food web to models generated for the NASB 2005 project. This project will include the training of graduate and undergraduate research assistants as well as the facilitation of outreach and diversification at an EPSCoR (Experimental Program to Stimulate Competitive Research) institution. Three graduate and four undergraduate students will be supported, and information from this program will be directly incorporated into courses, outreach events and web dissemination at the University of Tennessee. In recent years it has become increasingly evident that viruses play an important role in structuring the aquatic biological community, and in aquatic biogeochemical cycles. This project will examine the role of viruses during a field experiment designed to simulate the possible effects of a predicted long-term increase in atmospheric CO2 levels that would affect ocean chemistry. The field experiment (NASB 2005) uses the North Atlantic spring bloom of phytoplankton as a proxy for the longer-term changes that would result from CO2 increases. This project will provide essential information to the NASB 2005 project to determine how communities in the North Atlantic may react to the predicted changes in climate that may occur during the coming century.