OCE-PRF: Interannual variability in estuarine exchange due to oceanic forcing conditions and offshore river plumes

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In this project, the investigator will build upon current modeling efforts to explore the influence of river plumes at the estuary mouth and implications for ocean/estuary connectivity in the Pacific Northwest.Estuarine systems and their connectivity to the ocean influence important biological and biogeochemical processes such as nutrient exchange, productivity, larval recruitment, and acidification. Residual circulation governs the exchange between the ocean and the estuary and thus plays a large role in influencing these important processes within estuaries and along the coast. Many remote forcing mechanisms alter conditions at the estuary mouth and thus alter estuarine exchange. The purpose of this study is to investigate a less studied remote forcing mechanism: the influence of a plume at the estuary mouth and the implications for ocean/estuary connectivity. The investigator will test the following hypotheses: 1. The presence of a river plume at the estuary mouth during wind-driven downwelling and relaxation events strengthens the decrease and/or reversal of exchange flow due to downwelling alone 2. Interannual variability in estuarine exchange flow in the Pacific Northwest (PNW) are governed by variations in river plume location and volume 3. Plume presence decreases ocean/estuarine connectivity while enhancing along-coast connectivity To address these hypotheses, the investigator will build upon current modeling efforts to understand ocean-estuary interactions in the PNW estuaries of the Salish Sea (the inland Washington and Canadian waters including Puget Sound and the Strait of Georgia), Grays Harbor, Willapa Bay, Tillamook Bay and Coos Bay. The research will take advantage of an already developed regional modeling system and extensive observational datasets. Further model development will incorporate additional runoff sources from a hydrologic model and nested sub-grids to resolve smaller estuaries. Model runs over a decade both with and without the Columbia River inflow will be used to address the above hypotheses. Although there is a particular interest in understanding PNW estuaries, this work relates more broadly to better understanding of estuaries along upwelling coasts as well as estuaries influenced by offshore river plumes. The broader impacts include educational opportunities for the public and students through established outreach mechanisms. The investigator will build upon existing visualization tools to develop an interactive museum exhibit and classroom tool that uses the model output to visualize circulation and water properties within the Salish Sea emphasizing the connectivity with the ocean. The exhibit will use a touchscreen interface to run an interactive program with directed learning objectives and contain an exploratory mode. Centers for Ocean Sciences Education Excellence (COSEE) and Ocean Inquiry Project (OIP) have offered to act as host organizations. COSEE will help establish connections with other outreach programs and informal science learning centers to determine the best location for testing initial exhibits and visualization tools as well as provide guidance on setting learning objectives appropriate for the broad audience expected to interact with the exhibit. OIP will also provide guidance on learning objectives and help evaluate the tools by providing access to their boat-based outreach program and in teacher training activities as test venues. This project is supported under the NSF Ocean Sciences Postdoctoral Research Fellowship (OCE PRF) program, with goals to support novel research by early career scientists and increase the diversity of the U.S. ocean sciences workforce and research community. With OCE-PRF support, this project will enable a promising early career researcher to establish themselves in an independent research career related to ocean sciences and broaden participation of under-represented groups in the ocean sciences.