Project: Does Rhode Island Sound fuel harmful algal blooms in Narragansett Bay?

Award Abstract:

Since nutrient reductions from wastewater treatment plants that discharge into Narragansett Bay have been implemented, the nutrients that fueled the 2016 HAB event in Narragansett Bay likely came from elsewhere. One hypothesis is that Rhode Island Sound feeds nutrients into Narragansett Bay that may fuel harmful algal blooms.

During that event, significant concentrations of the HAB species Pseudo-nitzschia were observed in Rhode Island Sound east of the mouth of Narragansett Bay. Recent work indicates that meteorologically driven intrusions of these waters into Narragansett Bay occur sporadically during the summer. This project seeks to better understand the role of these intrusions on HABs in Narragansett Bay.

Improved scientific understanding of and management strategies for the relationship between estuarine-shelf physics, nutrient dynamics and healthy versus unhealthy blooms requires improved data and modeling tools. Rhode Island Sea Grant-funded researchers are investigating the relationship between estuarine-shelf physics, nutrient dynamics, and healthy versus unhealthy blooms by applying the Regional Ocean Modeling Systems (ROMS), developed from previous funding, to better assess shelf-estuary exchange physics and the associated nutrient-biological exchange fluxes.

To obtain volume and nutrient flux measurements, two moored stations in the lower East Passage and off Brenton Point. Mussels, provided by American Mussel Harvesters, will be sampled weekly to monitor the presence of harmful algae. Data will be used along with realistic Bay/shelf models to produce improved estimates of nutrient intrusion flux, how these products move into the estuary and interact with terrestrial sources for driving different styles of blooms.

The outcomes of this project are intended to improve the predictability of harmful algal blooms in Narragansett Bay.