IRFP: Functional Genes of Marine Iron Reducing Microorganisms

Reyes Carolina, Santa Cruz CA

Investigators

Abstract

The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award is co-funded by the Office of International Science and Engineering and by the Centers of Research Excellence in Science and Technology Program in the Human Resource Development Division. This award will support a twenty-four month research fellowship by Dr. Carolina Reyes to work with Prof. Michael Friedrich at the University of Bremen in Germany. In collaboration with Prof. Dr. Kai-Uwe Hinrichs at the Center for Marine Environmental Sciences (MARUM) in Bremen, Prof. Dr. Frank Oliver Glöckner, at the Max Planck Institute for Marine Microbiology in Bremen and Prof. Dr. Bo Thamdrup at the University of Southern Denmark in Odense, this project will determine if certain members of the Geobacteraceae bacterial family are among the microorganisms present in sediments from the Baltic Sea. Using a stable isotope technique, metabolically active microorganisms will be identified in these sediments. Gene fragments expressed in the iron reduction zone of these sediments will be sequenced and screened for possible iron reducing genes. This project anticipates elucidating a diverse community of bacteria capable of reducing iron, including members of the Geobacteraceae family. The ocean contains a vast amount of microbial diversity and activity in its waters and sediments including microorganisms capable of breathing solid iron minerals. Microbial iron reduction has been intensely studied in a few model microorganisms, however it remains poorly understood which microorganisms are responsible for iron cycling in marine sediments, which biochemical pathways they use, and how they are capable of turning on certain genes that are responsible for this pathway. This project addresses this knowledge gap through the study of gene expression and microbial diversity in sediments collected in the Kattegat and Skagerrak region of the Baltic Sea. In this area, sediments are particularly iron rich, and previous geochemical and sediment-incubation studies have shown that iron is reduced at high rates. Searching for iron-reducing functional genes in natural sediments may not only lead to the discovery of novel organisms and gene products in marine sediments, but will contribute to a fundamental understanding of how biogeochemical pathways are distributed and how microbial life functions in the environment. Such an understanding is essential to human society becoming more and more aware of how its activity can affect the microbial world and therefore also the global geochemical cycles.