Delaware Sea Grant funded a combination of drone-based techniques, kayak surveys, and manual ground surveys to map over 1,600 acres of tidal waters within the Inland Bays for the presence or absence of seagrasses. Survey results resulted in the direct protection of these areas, and planting efforts to expand them. Comparisons between two drone-based techniques and kayak surveys were also made to infer the relative efficiency and the benefits and drawbacks of each method.

In the face of sea level rise, Delaware Sea Grant funded research that underscored the importance of the Delaware Bayshore for hundreds of thousands of migratory songbirds and the economic and environmental payoff this resource provides on both a local and global scale.

Investigators: Drs. Jennifer Biddle and Christopher Main

Delaware Sea Grant funded research to perform microbial source tracking to guide conservation practices, permitting decisions and pollution control strategies for water quality improvement. Evaluation of the variability in the dissolved organic matter composition identified different organic matter compositions for areas draining forested versus agricultural land uses and for winter versus summer and fall. Fluorescence spectroscopy was evaluated for the purpose of understanding how well it can trace organic matter sources to waterways.

Investigator: Dr. Carlos Moffat

Sediment transport research at Prime Hook National Wildlife Refuge indicates that the net flux of suspended sediment is highly time dependent and predominantly influenced by coastal storms.

Investigator: Dr. Jack Puleo

Delaware Sea Grant funded research to perform numerical simulations of beach erosion using an open source model to determine model predictive capability during an extreme event. Nor’Easter and hurricane forcing affects the East coast, including Delaware, and Gulf coast areas of the United States. Extreme event energy causes severe erosion and infrastructure damage. However, data collected during extreme events, which are necessary to understand the fundamental processes and time scales over which they occur, are scarce. In response, Delaware Sea Grant funded researchers to develop and produce inexpensive sensor modules that could be rapidly deployed prior to extreme events. Researchers were able to use these sensors to collect hydrodynamic and bed level data response during extreme events. Data, which were collected during Nor’Easters and storms in the winter of 2018 and 2019, were combined with offshore survey data collected by the Delaware Department of Natural Resources, to better understand and predict storm forcing. Extreme event energy frequently causes severe erosion and infrastructure damage. Numerical models, including the open source XBeach, are used to understand and predict these effects. However, these models are almost exclusively validated with pre- and post-event morphology data. The models are tuned to match the final beach configuration without specific validation of the underlying hydrodynamics or sediment transport magnitudes that lead to the final beach configuration. Intra-event data are needed for full model validation. In response, Delaware Sea Grant funded research to evaluate the efficacy of XBeach, which demonstrated moderate predictive performance, but with some temporal deficiencies with respect to morphodynamics and hydrodynamics.

Investigators: Drs. Tobias Kukulka and Jon Cohen

Acute mortality studies and chronic culturing studies with the copepod Acartia tonsa suggest concentrations of microbeads at or above those potentially experienced in Delaware Bay do not result in major lethal or sublethal effects. Potential negative effects of longer duration exposures, and exposure to other microplastic types, remain unknown.

Investigators: Drs. John Madsen and Dewayne Fox

Delaware Sea Grant worked with researchers from Delaware State University and the U.S. Fish & Wildlife Service to better understand the estuary-wide reporting rate for dead Atlantic Sturgeon that wash ashore in Delaware Bay. DESG and partners have also worked to extrapolate a conservative estimate of the total number of fatalities associated with the reports of observed deaths from 2005-2019. Delaware Sea Grant research integrated acoustic telemetry, side-scan sonar, bottom sampling, and gut content analyses to examine the temporal distribution of endangered Atlantic Sturgeon within the lower Delaware Bay, and thereasons why they congregate in such large numbers in what is one of the most heavily transited and at-risk areas in the Delaware River Estuary.

Investigators: Drs. Tom McKenna, Naomi Bates, and John Callahan

Delaware Sea Grant funded research to perform numerical simulations of beach erosion using an open source model to determine model predictive capability during an extreme event. Nor’Easter and hurricane forcing affects the East coast, including Delaware, and Gulf coast areas of the United States. Extreme event energy causes severe erosion and infrastructure damage. However, data collected during extreme events, which are necessary to understand the fundamental processes and time scales over which they occur, are scarce. In response, Delaware Sea Grant funded researchers to develop and produce inexpensive sensor modules that could be rapidly deployed prior to extreme events. Researchers were able to use these sensors to collect hydrodynamic and bed level data response during extreme events. Data, which were collected during Nor’Easters and storms in the winter of 2018 and 2019, were combined with offshore survey data collected by the Delaware Department of Natural Resources, to better understand and predict storm forcing. Extreme event energy frequently causes severe erosion and infrastructure damage. Numerical models, including the open source XBeach, are used to understand and predict these effects. However, these models are almost exclusively validated with pre- and post-event morphology data. The models are tuned to match the final beach configuration without specific validation of the underlying hydrodynamics or sediment transport magnitudes that lead to the final beach configuration. Intra-event data are needed for full model validation. In response, Delaware Sea Grant funded research to evaluate the efficacy of XBeach, which demonstrated moderate predictive performance, but with some temporal deficiencies with respect to morphodynamics and hydrodynamics.

Investigator: Dr. Kathryn Coyne

A microscopic method was developed to identify sources of chloroplasts in Dinophysis cells that does not require isolating individual cells. The harmful dinoflagellate Dinopysis acuminata does not prey on Heterosigma akashiwo.