EDGARTOWN GREAT POND IS TURNING GREEN! THE ECOLOGICAL IMPACTS OF WASTEWATER POLLUTION ON COASTAL ESTUARIES

As anthropogenic activities continue to exert profound changes on the environment, estuaries and coastal ponds emerge as particularly vulnerable ecosystems. In the southeastern New England region, wastewater pollution poses a significant threat, contributing substantially to nitrogen inputs and subsequent eutrophication. Our ongoing research investigates the ecological consequences of wastewater pollution on Edgartown Great Pond in Martha's Vineyard. Over the course of two years, we have been able to identify grasses Ruppia maritima and Zostera marina as the primary producers of the food web in Edgartown Great Pond. Elevated 𝛅¹⁵N levels in the northern and eastern coves indicated wastewater pollution entry points, resulting in reduced diversity in the associated invertebrate community. Focusing on two coves with elevated 𝛅¹⁵N values, Mashacket Cove and Slough Cove, we revealed distinctive isotopic signatures indicative of agricultural and wastewater nitrogen sources. Wetland plants in Mashacket Cove were identified as potential nitrogen sinks. Analysis of periodic inlet openings between the pond and the sea demonstrated that successful cuts led to salinity increase and nutrient reduction, suggesting a potential mitigation strategy for mitigating nutrient pollution. Current work aims to test groundwater samples from Mashacket Cove and Slough Cove for metal content, 𝛅D, and 𝛅¹⁸O isotopes to identify specific metal infiltration sources and elucidate seasonal infiltration patterns. Analysis of biological tissue samples will also explore metal bioaccumulation and species susceptibility to metals. The gathered data holds promise for informing more effective nutrient pollution management strategies and policies for Edgartown Great Pond.