Salinity Variability and Water Exchange in Interconnected Estuaries
A high-resolution coastal ocean model is used to investigate salinity variability and water exchange in a complex coastal system off the southern U.S. characterized by three adjacent sounds that are interconnected by a network of channels, creeks, and intertidal areas. Model results are generally highly correlated with observations from the Georgia Coastal Ecosystem Long Term Ecological Research (GCE-LTER) program, revealing a high degree of salinity variability at the Altamaha River and Doboy Sound, decreasing sharply toward Sapelo Sound. A Lagrangian particle tracking method is used to investigate local residence time and connectivity in the system. Local residence time is highly variable, increasing with distance from the Altamaha River and decreasing with river flow, revealing that discharge plays a dominant role on transport processes and estuary-shelf exchange. The Altamaha River and Doboy Sound are connected to each other in all seasons, with exchange occurring both via coastal and estuarine pathways. While particles released at the Altamaha and Doboy rarely reach Sapelo Sound, particles released at Sapelo Sound and the creeks surrounding its main channel can reach the entire estuarine system.
KeywordsResidence time Connectivity FVCOM Exchange
We thank two anonymous reviewers for their thoughtful and constructive suggestions. We gratefully acknowledge support by the National Science Foundation through grant OCE 1632090 and the Georgia Coastal Ecosystems Long Term Ecological Research program (GCE-LTER, OCE-1237140). Additional support was provided by an Institutional Grant (NA100AR4170098) to the Georgia Sea Grant College Program from the National Sea Grant Office, National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce and by grant award NA11NOS4190113 to the Georgia Department of Natural Resources (DNR) from the Office of Ocean and Coastal Resource Management (OCRM), NOAA. All views, opinions, statements, findings, conclusions, and recommendations are those of the authors and do not necessarily reflect the opinions of NSF, the Georgia Sea Grant college Program, DNR, OCRM, or NOAA.
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