Award: IOS-1656311

Almost a quarter of all primary production occurring annually on Earth is processed by the billion marine bacteria living in each liter of surface seawater. This uptake of highly biologically-available carbon dissolved in seawater occurs with hours to days of fixation. Surprisingly little is known, however, about the compounds present in seawater that sustain the growth of these heterotrophic bacteria and serve as the links between microbial autotrophs and heterotrophs in the ocean carbon cycle. This project identified phytoplankton-derived metabolites that are taken up by ocean bacteria and used for growth and respiration in this globally-important carbon flux. The project established bacteria-phytoplankton co-cultures that exploited the expression of microbial genes as a sensitive biological signal for identifying important compounds, and developed and used advanced chemical tools to identify and measure these molecules in laboratory and ocean studies. Graduate students and postdoctoral fellows were trained in interdisciplinary marine microbial biology. High school students were provided with experiential learning opportunities covering key goals in the biology curriculum, and particpated in class field trips to coastal Georgia and research internships at the University of Georgia. Overall, this project made signifcant progress in understanding carbon flux between microbes of the surface ocean, filling a key gap in our understanding of the global carbon cycle and training new scientists in interdisciplinary marine sciences. Last Modified: 03/31/2022 Submitted by: Mary Ann Moran