Allison Byrd, REU fellow 2016

Organic matter in highly eutrophic estuaries goes through several degradation steps before being buried in the sediments. These steps are carried out by microbes that live in both the water column and the sediments. Understanding the breakdown of this organic matter is important, as it produces carbon dioxide and ultimately, methane, which are powerful greenhouse gases. The objective of this study was to characterize the organic matter that is available to the sulfate reducing and methane producing bacteria. Doing this would allow us to see how it changes in relation to the activity of sulfate reducers and methane producers and if there are differences in how it is transformed through different biogeochemical zones. This was done by first determining biogeochemical zonation in the Chesapeake Bay through down core changes in concentrations of sulfate, sulfide, methane, chloride, and dissolved organic carbon. Pore water was then analyzed for fluorescent dissolved organic matter components using excitation emission matrix analysis and statistical PARAFAC analysis. Three statistically different dissolved organic matter components were confirmed to be in the pore water. Changes in fluorescence of each component through the biogeochemical zones was observed and thus it is possibility that it is utilized differently within these zones.

Learn more about the REU program and Allison here