Geoscience Reference
In-Depth Information
The densely populated coastal cities and suburbs of the U.S. eastern seaboard meld into a single megalopolis.
Adjacent estuaries and coastal waters are currently suffering from eutro-phication, or oxygen depletion, as
high levels of nitrates and phosphates from agriculture, atmospheric deposition, and sewage are flushed into
them. These pollutants may be responsible for the increased frequency and extent of plankton blooms resulting
in biotoxin-related shellfish poisoning and the closure of the region's beaches to swimming because of elev-
ated bacterial levels, and may even be responsible for mortalities in marine mammals.
A quarter of sediments near major urban areas contain unacceptably high levels of contaminants, and 10
percent of fish have elevated levels of contaminants in their edible tissues. Contamination with heavy metals,
such as zinc, cadmium, copper, lead, and nickel, is highest in southern New England, reflecting the high dens-
ity of population and intense industrialization of the region. In the same region, suburban sprawl has eaten all
but 2 percent of the original terrestrial habitat. Even so, the marshes, lagoons, barrier islands, and offshore wa-
ters within sight of this crush of people, asphalt, and concrete continue to be host to large numbers of seabirds,
waterfowl, shorebirds, and waders.
At the same time, far from the eastern seaboard's bright lights, vast areas, such as the hinterland of Lab-
rador's interior and its 20,000 kilometers (12,400 miles) of coastline, are known only to Aboriginal peoples—a
succession of Inuit and Indian cultures—who sparsely inhabited these lands long before European contact.
One of the oldest (10,600 bp) and richest Paleo-Indian sites in eastern North America is located at Debert,
Nova Scotia, at the head of the Bay of Fundy's Minas Basin. Although the continental glacier had long disap-
peared, archaeologists believe that local glacial remnants remained lodged in the nearby hills and that the ve-
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