Jamaica Bay - Area Description

Area Description

Jamaica Bay is a saline to brackish, eutrophic (nutrient-rich) estuary covering about 25,000 acres (100 km2), with a mean depth of 13 feet (4.0 m), a semidiurnal tidal range averaging 4.9 ft (1.5 m), and a residence time of about three weeks. The bay communicates with Lower New York Bay and the Atlantic Ocean via Rockaway Inlet, a high current area that is 0.6 mi (0.97 km) wide at its narrowest point, with an average depth of 23 ft (7.0 m). Measurements taken during recent surveys in Jamaica Bay indicate average yearly ranges for temperature of 34 to 79 °F (1 to 26 °C), salinity of 20.5 to 26 parts per thousand, dissolved oxygen of 3.5 to 18.5 milligrams/liter, and pH of 6.8 to 9. Loadings of nutrients and organic matter into the bay from sewage treatment plants and runoff result in phytoplankton blooms and high suspended-solid concentrations which, in turn, result in turbid water and low bottom dissolved oxygen concentrations.

Jamaica Bay is in the middle of the New York metropolitan area, and the uplands around the bay, as well as much of the Rockaway barrier beach, are dominated by urban residential, commercial, and industrial development. The bay itself has been disturbed by dredging, filling, and development, including the construction of John F. Kennedy International Airport and, earlier, the historic (and now defunct) Floyd Bennett Field. About 49 of the original 65 km2 (12,000 of the original 16,000 acres) of wetlands in the bay have been filled in, mostly around the perimeter of the bay. Extensive areas of the bay have been dredged for navigation channels and to provide fill for the airports and other construction projects.

The center of the bay is dominated by subtidal open water and extensive low-lying islands with areas of salt marsh, intertidal flats, and uplands important for colonial nesting waterbirds. The average mean low tide exposes 350 acres (1.4 km2) of mudflat, 940 acres (3.8 km2) of low salt marsh dominated by low marsh cordgrass (Spartina alterniflora), and 520 acres (2.1 km2) of high marsh dominated by high marsh cordgrass (Spartina patens). The extensive intertidal areas are rich in food resources, including a variety of benthic invertebrates and macroalgae dominated by sea lettuce (Ulva latuca). These rich food resources attract a variety of fish, shorebirds, and waterfowl. In addition, two freshwater impoundments were created on Rulers Bar Hassock in the Jamaica Bay Wildlife Refuge; the smaller 49 acres (0.20 km2) freshwater West Pond is kept as open water, and the larger 120 acres (0.49 km2) slightly brackish East Pond is controlled to expose mudflats. Some of the islands in the bay have upland communities, including grasslands consisting of little bluestem (Schizachyrium scoparium), switchgrass (Panicum virgatum), and seaside goldenrod (Solidago sempivirens); scrub-shrub containing bayberry (Myrica pensylvanica), beach plum (Prunus maritima), sumac (Rhus spp.), and poison ivy (Toxidendron radicans); developing woodland consisting of hackberry (Celtis occidentalis), willow (Salix spp.), black cherry (Prunus serotina), and tree-of-heaven (Ailanthus altissima); and beachgrass (Ammophila breviligulata) dune. Species introduced in the refuge to attract wildlife include autumn olive (Elaeagnus umbellata), Japanese black pine (Pinus thunbergii), and Japanese barberry (Berberis thunbergii).