CAREER: The Importance of Iron in the Remineralization of Organic Matter in Estuarine and Continental Shelf Sediments

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ABSTRACTOCE-0239376The fate and transformation of organic carbon in coastal and marine sediments is intrinsic to understanding the carbon cycle and its influences on global climate change. The objective of the proposed research by the PI was to examine the mechanisms of natural organic matter (NOM) transformation in estuarine and continental shelf sediments through in-situ technology and mathematical modeling. The research is based on the following two hypotheses: 1) microbial Fe(III) reduction accounts for a significant portion of NOM remineralization in the target regions, and 2) sufficient oxygen is supplied through bioturbation to recycle Fe(OH)3 efficiently for NOM remineralization. The PI proposed to construct a lander system with a benthic chamber, a micromanipulator and voltammetric microelectrodes to obtain in situ benthic flux data and microprofiles. This in situ data combined with sulfate reduction rates, solid phase and porewater data from sediment cores, and results from reactor experiments would be used to calculate NOM remineralization rates. The PI then proposed to develop a 3-D diagenetic model to predict NOM remineralization in continental shelf and estuarine sediments.Incorporating chemists and engineers into the chemical oceanography field was one of four objectives of the educational component. The PI proposed to involve students in these fields in the development of the lander system and the modeling effort. Additionally, a high school teacher would conduct a research project in the PI's laboratory during the summer as part of an existing program at GIT. The third component entailed development of a laboratory component of an existing Geochemistry course. This laboratory component would include cruises on the R/V Savannah to deploy the lander system and involve the students in the field and laboratory efforts of the proposed research. The fourth component consisted of a student exchange program involving GIT, Skidaway Institute of Oceanography, and European partners.