Carlyn Brecht, REU Fellow 2017
Abstract: Non-competitive and competitive substrates are two mechanisms in which methane can be produced in sediment. The methane production mechanism is due to oxidation-reductions reactions that are occurring within the sediment. Methane is a powerful greenhouse gas, and estuarine systems are one of the understudied provider of methane. The objective of this study is to understand how methane is being produced in sulfate rich sediments of an eutrophic estuary, the Chesapeake Bay. The study consisted of a top and bottom sediment incubation experiment which contained multiple non-competitive and competitive substrates, the non-competitive substrates included trimethylamine, dimethyl sulfide, and methanol and the competitive substrate was bicarbonate. The sediments were studied for a total of 42 days with 5-time points. The original hypotheses included non-competitive substrates having the highest methane production rates while the competitive substrate did not produce methane and the top sediment will have higher methane production rates in comparison to the bottom sediment. While the data showed evidence of the top sediment incubation producing higher methane production rates and the highest methane production rates being produced from competitive substrates, more questions arose about the experiment; therefore, a future study must be conducted to understand the methane production rates.
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