High Resolution Linkages Between DOC Turnover and Bacterioplankton in a Coastal Ocean

University Of Georgia Research Foundation Inc, Athens GA

Investigators

Abstract

Long-standing questions regarding the fate of dissolved organic carbon (DOC) in coastal oceans require a better understanding of the network that links bacterioplankton metabolism with carbon transformation. These questions address uncertainties about the composition of the bioreactive DOC components transformed in ocean margins, and the role of bacterial taxonomic and genetic composition in determining the fate of DOC. Intellectual Merit This project will infuse a new type of data into coastal carbon cycle research based on high-resolution chemical analysis coupled with bacterial gene expression measures. It will extend DOC process studies down to the single-compound level and bacterial activity studies down to the single-gene level, and integrate this information into existing bioinformatic resources for biogeochemical and modeling applications. The specific goals of the project are: 1) To reconstruct major components of the network linking DOC composition, DOC turnover, and bacterial heterotrophy in the coastal ocean (the composition of the DOC pool, the major bioreactive components, the bacterioplankton taxa mediating transformations, and the bacterial genes and pathways responsible). 2) To test hypothesized network links for selected DOC compounds using a simplified system that queries individual DOC compounds against a complex natural microbial community. 3) To test hypothesized network links for marine bacteria using a simplified system that queries a single generalist heterotrophic bacteria against a complex natural DOC pool. 4) To verify predicted DOC-gene linkages that are most informative about heterotrophic activities of bacterioplankton. Broader Impacts This research addresses fundamental questions on bacterial mediation of organic carbon fate in the ocean and atmosphere. As such, these investigations linking the chemical changes in dissolved organic carbon with patterns of gene expression in coastal bacterioplankton communities will be of interest to scientists across several disciplines. The project will train graduate students and postdoctoral associates in the departments of Marine Sciences, Microbiology, Chemistry, and Ecology at the University of Georgia, and provide research opportunities and mentoring for undergraduate students. Students will obtain interdisciplinary training in microbial ecology, carbon biogeochemistry, marine chemistry, and bioinformatics. An outreach program will enhance understanding of the ecological roles of marine microorganisms for several cohorts of promising high school students. PIs will collaborate each summer with an Advanced Placement Biology teacher at a racially diverse Athens, GA, high school to develop laboratory exercises that accomplish experiential learning goals of the revamped AP Biology curriculum. Exercises will be designed around bacterial strains isolated by each high school student from coastal Georgia seawater, and PIs will collaborate in the testing and evaluation of the laboratory exercises during the school year. Publications in educational journals and web sites will make the exercises widely available.