Citation:

O'Brien, L. AND S. Ayvazian. Comparing and determining the causes of ribbed mussel nitrogen isotope signatures in three New England sub-watersheds. New England Estuarine Research Society (NEERS) Fall Meeting, Block Island, RI, October 20 - 22, 2016.

Impact/Purpose:

This research describes the use of the ribbed mussel as an indicator of the source of nitrogen input to local watersheds.

Description:

Geukensia demissa, the ribbed mussel, is a useful indicator of sources of nitrogen input into coastal watersheds as it possesses a slow tissue turnover rate and is a common salt marsh species. During the summer of 2016, we sampled ribbed mussels from three New England sub-watersheds, Ocean Heights and Farm Neck sub-watershed, Massachusetts, and Greenwich Cove watershed, Rhode Island, for their nitrogen and carbon isotope signatures. We found the isotope signatures were consistent with historical isotope data from these three sites. We then determined shell length and condition index of the mussels as well as total suspended solids and particulate organic matter in the water to explain the isotopic signatures. The results provided information that suggests the nitrogen isotopic signatures from the two sub-watersheds in Massachusetts are indicative of a mix of synthetic fertilizer and wastewater. Despite upgrades to the major waste water treatment facility in the Greenwich Cove sub watershed, the mussels still contain a nitrogen isotope signature indicative of wastewater. We plan to investigate the isotope signatures of ribbed mussel food sources in the respective watersheds and the total nitrogen loads of the watersheds to more conclusively explain the isotopic signatures to provide useful information for nutrient management in coastal watersheds.

Record Details: