Gulf of Maine - Geographic Features and Biological Importance

Geographic Features and Biological Importance

The coastline of the Gulf of Maine is predominantly rocky and scenic; the only significant coastal developments are located in the Boston, Portsmouth, Portland and Saint John metropolitan areas. The effects of glaciation are responsible for stripping sedimentary soil away from the coastline, therefore the gulf lacks the sandy beaches found to the south along the Eastern Seaboard. The underwater features of the seabed sculptured during the lower sea levels of the ice ages make the gulf a semi-enclosed sea bounded to the south and east by underwater banks. Georges Bank in particular, on its southern end, protects the Gulf of Maine waters from the Gulf Stream. Gulf of Maine waters are more strongly influenced by the Labrador Current, making the gulf waters significantly colder and more nutrient-rich than those found to the south. Undersea valleys in the central basin can reach depths of 1,500 feet (500 m) while undersea mountains rise up 800 feet (266 m) from the sea floor, almost reaching the surface in some locations, or even exceeding it, creating islands.

There are three major basins contained within the Gulf of Maine: Wilkinson Basin to the west, Jordan Basin in the northeast, and Georges Basin in the south, which are isolated from each other beneath the 650 foot (200 m) isobath. Georges Basin, just north of Georges Bank, is the deepest of the three at just over 1200 feet (370 m) and generates a pocket at the end of the Northeast Channel, a deep fissure between Georges Bank and Browns Bank, the southwestern edge of the Nova Scotian Shelf. The Northeast Channel is the major channel between the Gulf and the rest of the Northwest Atlantic. A secondary, shallower connection to the rest of the Atlantic is the Great South Channel, located between Georges Bank and the Nantucket Shoals.