The Virginia Institute of Marine Science (VIMS) is one of the largest marine research and education centers in the United States. Founded in 1940, VIMS is unique among marine science institutions in its legal mandate to provide research, education, and advisory service to government, citizens, and industry. Funding for VIMS comes from the Commonwealth of Virginia, grants and contracts from federal and state agencies, and private giving. The School of Marine Science (SMS) at VIMS is the graduate school in marine science for the College of William & Mary. Offering both M.S. and Ph.D. degrees in marine science, the school has 57 faculty members, an enrollment of 80-100 students, and includes 4 academic departments. VIMS' main campus is located in Gloucester Point, Virginia.
The eastern oyster is an important bivalve species in coastal Louisiana due to its role as an ecosystem engineer and its high commercial value. Given the importance of larval growth, mortality, and transport in shaping oyster population dynamics, we developed a coupled hydrodynamic-larval transport model and simulated years 2014 to 2018. The model was used to examine the spatial pattern of oyster larval dispersal during spring spawning season and to explore the environmental drivers of larval growth in Barataria Estuary, Louisiana. Low salinity was the primary factor contributing to reduced larval growth and increased mortality, driven by both low mean conditions and prolonged exposure to low-salinity environments (< 7.5 PSU) associated with high salinity variability, whereas temperature did not differ substantially between dead and settled larvae. Reduced larval growth and settlement failure heavily influenced estuarine subregion connectivity. Specifically, only one subregion in the southwestern region of the estuary was not impacted by low salinity, making that subregion potentially self-sustaining. In contrast, settlement in other subregions relied on larval inputs from adjacent areas. Although low salinity due to increased river discharge was adverse to larval settlement in the model, other factors such as turbidity, food supply, and the joint effects of multiple stressors would be important in nature. Including these factors in future model development will contribute to more accurate simulations of oyster larval growth, dispersal, and settlement across the oyster grounds under changing estuarine environments. Given the strong spatial heterogeneity in oyster larval dynamics, larval transport models offer critical insights for oyster restoration and management strategies. Comprehensive field observations with adequate spatiotemporal resolutions are essential for future model development and performance evaluation.
Abstract Mesoscale eddies are physically dynamic environments, yet biological responses within them are often treated as static, with eddy polarity (anticyclones vs. cyclones) serving as the dominant conceptual framework. Temporal dynamics of animals within eddies—particularly at mid‐trophic levels—remain largely unresolved. We tracked a long‐lived anticyclonic eddy in the Northeast Atlantic for nearly a month using a Lagrangian framework, generating one of the few continuous time series of mesopelagic fish distribution within an eddy. Coupled physical–biological observations revealed marked vertical changes following a major wind storm: compact fish aggregations dispersed as phytoplankton distributions expanded and zooplankton deepened, despite comparable integrated fish biomass before and after. These results show that aggregation dynamics of mesopelagic fishes are modulated by bottom‐up variability on weekly to monthly timescales. By moving beyond static snapshots, our study demonstrates that eddies function as dynamic ecosystems whose ecological roles in pelagic food webs evolve through time.
Glacial melting in West Antarctica has intensified with the increased intrusion of warm ocean water beneath ice shelves, but the processes controlling the export of meltwater-associated micronutrient iron (Fe) to Southern Ocean surface waters remain unclear. Here, we report Fe concentrations and dissolved Fe (dFe) isotope ratios in the inflowing deepwater layer that drives melting of the Dotson Ice Shelf and in the meltwater-enriched outflow to determine meltwater-derived dFe. Isotopic mass balance points to an anoxic Fe-reducing region of the upstream subglacial hydrologic system as the dominant source of meltwater dFe, rather than ice shelf melt itself. Remarkably, total meltwater contributes only similar to 10% of outflowing dFe, with the majority contributed by inflowing deep water (62%), augmented by inputs from shelf sediments (28%). Outflowing suspended particulate Fe exceeds inflow by 46%, at 100 times the dFe concentration, with 25% in reactive phases. Predictive models of future ecosystem effects should consider that the primary role of ice shelf melting is to provide buoyancy that transports Fe from deep sources to the Fe-limited surface ocean, stimulating phytoplankton growth.
The placement of dredged sediment on salt marshes, often termed “thin layer placement” (TLP), is a promising strategy to offset elevation loss and combat marsh degradation. However, inconsistent terminology, reporting practices, and lack of standardized quantitative success criteria hinder synthesis and guidance development. To address these gaps, we reviewed 89 TLP-related papers, reports, and other documents to evaluate reporting conventions and identify opportunities for standardization. Our analysis revealed substantial variability in methodology and reporting, limiting cross-project comparisons and other meta-analysis. For example, 57
Accurate simulation of compound flooding in the coastal transition zone requires a fully coupled hydrologic-hydrodynamic modeling system to capture the complex interactions between inland and oceanic floodwaters. Despite recent advances in fully coupled 3D modeling frameworks, significant challenges persist in resolving flow through intricate river networks, especially where small channels are poorly represented due to limitations in digital elevation models (DEMs). This study addresses these challenges by enhancing the model meshing process and evaluating coupling strategies in the lower Mississippi River region, a representative coastal transition zone with a dense and complex river network. We improve a previously developed semi-automatic meshing approach by incorporating the National Hydrography Dataset to ensure clean delineation and connectivity of small channels where DEM uncertainties often cause artificial blockages. We also assess two strategies for integrating hydrologic model outputs into the hydrodynamic domain: (1) a conventional "hand-off" method that imposes freshwater streamflows at the land boundary combined with spatially varying precipitation, and (2) an alternative scheme that distributes hydrologic outputs at every resolved channel within the hydrodynamic mesh. Results show that the enhanced mesh, combined with updated topographic data, substantially reduces domain-wide bias and improves water-level skill at inland USGS stations. The alternative coupling scheme produces results comparable to the base method, providing an extensible framework for potential future development. By improving inland channel resolution and establishing a pathway for deeper coupling with hydrologic models, this work strengthens the scientific foundation and contributes to the operational readiness of compound flood forecasting.
