This case study reviews water quality characteristics of the Barnegat Bay-Little Egg Harbor Estuary, including DO, turbidity, nutrients, chlorophyll, phytoplankton blooms, and benthic primary producers. Long-term changes and ecosystem impacts also are discussed with an emphasis on eutrophication and impacts on aquatic life. While this case study does not focus directly on developing numeric nutrient criteria, aspects of the study are directly relatable to several process components of criteria development.
Healthy seagrass communities, as measured by areal extent of colonization, and healthy shellfish resources are assessment endpoints for management of the Barnegat Bay-Little Egg Harbor Estuary. It is estimated that as much as 25 percent of the submerged aquatic vegetation (SAV) in Barnegat Bay and 60 percent of the SAV in Little Egg Harbor has been lost since the mid-1970s. Field surveys documented that two-thirds of the hard clam standing stock was lost between 1986 and 2001.
The estuary is roughly divided into northern and southern segments—The northern segment is north of Barnegat Inlet and the southern segment is south of the inlet. The Barnegat Bay-Little Egg Harbor Estuary is classified as highly eutrophic based on excessive nutrient loading and characteristics that include shallow depth, poor flushing, and a heavily developed watershed. Increased nutrient loading has increased phytoplankton density and reduced light availability for SAV. Increased microalgal and macroalgal growth reduces the availability of benthic habitat and alters sediment chemistry and DO levels, which affects shellfish stocks (e.g., bay scallops and soft and hard clams).
The highest phytoplankton production and chlorophyll a concentrations, and turbidity occur in the northern segment of the estuary because of the greater nutrient loading from its more developed watershed, compared to the southern segment.
Water quality data in the Barnegat Bay-Little Egg Harbor Estuary were collected by various researchers. Parameters include nutrient concentrations, nitrogen loading, chlorophyll a, and salinity. SAV coverage and standing stock of hard clams also are documented (National Estuarine Experts Workgroup 2010).
Reference:
National Estuarine Experts Workgroup. 2010. Nutrients in Estuaries: A Summary Report of the National Estuarine Experts Workgroup 2005–2007. U.S. Environmental Protection Agency. Accessed October 2016. https://www.epa.gov/sites/production/files/documents/nutrients-in-estuaries-november-2010.pdf.