The Gulf of Maine
Offshore from Nova Scotia, New Brunswick, Maine, New Hampshire, and Massachusetts is "New England's own ocean," the Gulf of Maine. Shallow underwater banks of sand and gravel, primarily Georges Bank and Brown Bank, form its eastern rim and separate the Gulf from the rest of the Atlantic Ocean.
In the spring, rivers carry melting snow to the Gulf of Maine. This makes it colder, less salty, and more fertile than the deeper Atlantic Ocean. The rivers carry food, minerals and decaying plants to the many microscopic plants and animals of the Gulf plankton. Huge tides, as much as 40 feet high, help to mix the waters of the Gulf. A gyre, a circular current, fueled by the spring snowmelt of rivers flowing into the sea, moves nutrients, plankton, fish, and pollution in a counterclockwise direction around the Gulf. In addition, as colder, dense surface water sinks in spring, it displaces and pushes up the bottom water that is rich in nutrients that have sunk to the bottom of the Gulf. This process is called upwelling.
These nutrients, from rivers, runoff and upwelling, nourish vast quantities of life from microscopic plankton to the whales that visit the Gulf of Maine each summer. Like other tourists, humpbacks, fin whales, and minke whales enjoy the cool waters and the abundant food. In the winter, they migrate to the tropics where the mothers give birth.
Plankton is the food that nourishes all life in the Gulf, directly or indirectly. The term plankton means "wanderer," and these organisms swim only feebly or are moved passively by the wind, waves, and currents. Phytoplankton, plant plankton, are the basic producers in the sea, as green plants are on land. They use the energy of the sun to produce oxygen and starches and sugars. Phytoplankton reportedly produce 80% of the oxygen we breathe.
Many animals, including tiny floating zooplankton, feed directly on plant plankton. Zooplankton increase dramatically when phytoplankton bloom, responding rapidly to the increase in food supply.
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Gulf of Maine Curriculum Resources Table of Contents links