The carbon cycle and other biogeochemical processes in the oceans were thought to be controlled nearly entirely by two types of marine microbes: 1) phototrophs - microbes which, like plants, synthesize organic material using CO2 and other plant nutrients while producing oxygen; and 2) heterotrophs - microbes which, like animals, oxidize organic material back to CO2 and other plant nutrients while using oxygen. Recent studies using molecular approaches have discovered some novel microbes--photoheterotrophs--that combine phototrophy with heterotrophy. Photoheterotrophy would fundamentally alter our understanding of the carbon cycle and other biogeochemical processes in aquatic ecosystems.
This project would establish a Microbial Observatory (MO) in the Mid-Atlantic Bight to address questions about the diversity, abundance, and activity of photoheterotrophic microbes. The project will sequence relevant genes of photoheterotrophic microbes to characterize their diversity and metabolism. Abundance will be estimated by flow cytometry (cyanobacteria), infra-red microscopy of bacteriochlorophyll (AAP bacteria), and fluorescence in situ hybridization with polyribonucleotide probes targeting proteorhodopsin genes. Consumption of various organic compounds and CO2 will be assayed at the single cell level using microautoradiography together with fluorescence microscopy.
Broader Impacts This proposed MO project would offer several unique opportunities to contribute to the education of students and the general public in aquatic microbial ecology and environmental microbiology. The project will involve graduate students via a growing connection between the University of Delaware and The Institute for Genomic Research (TIGR). Undergraduates from Lincoln University, the nation's oldest historical black college, will conduct independent research in the summer in Delaware. Dr. Kirchman's lab is featured during weekly tours of University of Delaware facilities in Lewes (about 1000 visitors per year) and during Coast Day, an annual open-house in Lewes that attracts about 10,000 visitors.
