Collaborative Research: Biocatalytic Filtration and Carbon Cycling in Permeable Sediments

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ABSTRACTOCE-0424967Permeable sands cover approximately 70% of the continental shelves but it is not fully known how organic matter that settles to the shelf sediment is processed in permeable sands. In general, diagenetic processes are poorly understood in sands largely because standard approaches developed for fine-grained sediments fail to accurately mimic in situ conditions in sands. However, due to rapid porewater transport, the dynamics of uptake, metabolism, and release of organic matter in permeable sediments are fundamentally different from those in fine-grained, relatively impermeable, marine sediments. Recent in-situ measurements using innovative techniques suggest that shelf sands act as a large biocatalytic filter that efficiently removes and rapidly degrades dissolved/particulate organic matter from the water column, implying that shelf sands play a central role in the cycling of organic matter. Researchers from Florida State University, along with colleagues from University of Virginia and University of North Carolina, will generate a comprehensive dataset quantifying advective solute and particle fluxes, and mineralization rates in permeable shelf sediment subjected to current-induced pore water exchange. The data will be integrated by a model of coupled transport and reaction in permeable shelf sands, permitting improvement over existing diagenetic shelf sediment models, and generating a tool with predictive ability for managers and policy makers. These results will foster understanding of the continental shelf which is the most productive, economically most important, and at the same time the most threatened oceanic environment. On the local level, project results will be directly applicable to management and conservation efforts in the Apalachicola Bay region of Florida, which is the designated study area. On an international scale, the project will start a new research network in the area of permeable shelf sediments that will be linked to an existing program for the European Union.