<b>ZETAPROTEOBACTERIA IN THE SALTMARSHES OF CHARLESTON, SC</b>

Abstract

The deep ocean hydrothermal vents are a source of high amounts of iron. Zetaproteobacteria are the only organisms known to oxidize iron in such an environment under nearly neutral pH conditions. Previous research identified their ability to grow on carbon steel and, recently, in estuarine environments such as Chesapeake Bay. Given these recent findings, it is possible that Zetaproteobacteria live in the Charleston Bay area. The goals of this study were to identify areas in Charleston where Zetaproteobacteria grow and observe the impact of changing salinity gradients on their community composition in a coastal salt marsh environment. Sediment samples were collected at low tide across sites from the Ashley, Wando, and Cooper rivers and harbor of Charleston, South Carolina. Dissolved oxygen, temperature, and salinity measurements were obtained from the USGS water data. In addition, iron (II) and total iron were determined using a ferrozine assay. PCR analysis suggested Zetaproteobacteria were present in Charleston and that there is a change in their presence through space and time. Sequencing and statistical analysis revealed that salinity has a significant effect on overall bacterial composition and on Zetaproteobacteria composition, as does the origin of sampling (different rivers and the harbor) and temperature. Observing how these bacteria grow in the Charleston estuary and its salt marshes will allow for a better understanding of Zetaproteobacteria biogeography and the potential contribution of these bacteria to the global iron cycle.