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IPY - USGS Proposal

TITLE: Bacterial and bacteriophage interactions and the impact these interactions have on the geochemical and nutrient cycles in polar regions

STUDY AREA: This study topic will apply to both polar regions.

PRINCIPAL INVESTIGATOR(S): John T. Lisle, Center for Coastal & Watershed Studies, 600 Fourth Street South, St. Petersburg, FL 33701, Phone: 727-803-8747, ext. 3140, E-mail: jlisle@usgs.gov

INTRODUCTION: Autotrophic production of organic carbon and its subsequent mineralization via microbial heterotrophic metabolism drives bio-geochemical processes and influences bacterial species abundance and diversity in all ecosystems. The timing and magnitude of organic carbon production is particularly critical in ecosystems that are under extreme environmental conditions, like the polar regions of earth. Bacteria and their viruses (i.e., bacteriophage) play a central role in geochemical processes (e.g., cycling of carbon, nutrients and metals). In most of the aquatic systems located in the polar regions, these types of microbial processes dominate as the harsh conditions of the regions have prevented or inhibited the establishment of top-down controls (e.g., grazing) as seen in waters in more temperate climates. The inclusion of bacterial and bacteriophage dynamics and how their interactions influence geochemical processes is necessary if we are to understand what drives carbon, nutrient and metal cycling in these extreme environments.

OBJECTIVES:

1. Establish the abundance of bacteria and bacteriophage in selected areas of the polar regions.
2. Determine the secondary (bacterial) productivity and how bacteriophages influence this process.
3. Determine how the "microbial loop" influences the flow of carbon and distribution of nutrients within selected systems.
4. Assess how these microbial activities alter geochemical processes, such as iron cycling. [See Lisle & Priscu (2004). The Occurrence of Lysogenic Bacteria and Microbial Aggregates in the Lakes of the McMurdo Dry Valleys, Antarctica. Microbial Ecology, 47:427 - 439]

COOPERATORS:
(USGS, other agencies, university-based researchers, other countries, etc.) Cooperators will include USGS, Potential university-based researchers include John Priscu, Christine Foreman (Montana State University), Jack DiTullio, Peter Lee (College of Charleston), and National Science Foundation.