Geoscience Reference
In-Depth Information
4
LINES OF SHELLS
—surf clams, cockles, and bay scallops— shine under the strong, pewter-hued light streaming
through a bank of dark cloud hanging ominously over New Jersey's Island Beach State Park. The carcass of a
small shark is partially covered by sand at the wrack line. Just offshore, a common loon cruises parallel to the
coast, its seemingly star-checkered body periodically dipping below the waves as it feeds; farther out, gannets
are plunge-diving, sending up tiny explosions of spray as they enter the sea. Surf casters string out along the
beach, trying their luck for striped bass and bluefish, while small flocks of great black-backed gulls huddle
against the strong winds whipping the sand into the air and driving it, glittering, inland.
The Mid-Atlantic Bight is bounded by two capes—Cape Cod in the north and Cape Hatteras in the south. A
distinctive feature of this ecoregion is the barrier islands, like Island Beach, New Jersey, ribbons of sand that un-
furl for more than 3,000 kilometers (2,000 miles). This barrier island system actually begins north of Cape Cod,
at the mouth of the Merrimack estuary—Plum Island and Salisbury Beach in Massachusetts—but it finds its
most dramatic expression in Massachusetts in the dunes of Cape Cod, Martha's Vineyard, and Nantucket Island.
The shorelines of Rhode Island and Long Island, New York, are also guarded by barrier beaches and spits con-
solidated from glacial sediments. Then, beginning with the unglaciated coast of New Jersey, an almost continu-
ous chain of barrier islands strings along the Atlantic coast and reaches around Florida's panhandle into the Gulf
of Mexico.
The bright eye and bill of the oystercatcher probes for invertebrate prey in the shallows.
Built up and shaped by the pounding surf, these islands not only protect the land behind them but furnish a
mosaic of wildlife habitats, from energetic ocean beaches to scrubby maritime forests in the interior of the is-
lands, to more tranquil but teeming salt marshes and lagoons on their landward side.
Rising sea level since the last glaciation has created not only barrier islands but also a series of estuaries be-
hind them, where freshwater drains into the embayments formed between the island and mainland. Long Beach
