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Common dolphins dive through the rich waters of the Gulf of Maine, feeding ground for cetaceans large and small.
Garden in the Sea
The Gulf of Maine has been called “a garden in the sea” for its high productivity. Most of the oceans of the
world are, in fact, watery deserts, largely because of a lack of available nutrients to feed the growth of phyto-
plankton, the single-celled plants that are the foundation of biological productivity in the oceans. Besides a
supply of nutrients, phytoplankton need sunlight to power the process of photosynthesis, whereby they convert
the sun's energy into organic material and produce oxygen as a by-product.
These two ingredients—nutrients and sunlight—are amply satisfied within the Gulf of Maine. Nutrients are
continuously supplied from the Atlantic by waters seeping through the Northeast Channel, which is 61 kilo-
meters (38 miles) long and 35 kilometers (22 miles) wide. The gulf is also 5°C colder than water to the south
of it, and these cold waters are critical for providing the right combination of temperature and salinity needed
by cod, haddock, flounder, and other fishes. The relatively low salinity and temperature of the coastal gulf wa-
ters is due to the freshwater from rivers pouring directly into the gulf as well as the massive outflow of fresh-
water from the far away St. Lawrence River.
These cold waters hold more oxygen and carbon dioxide in solution than warmer water, amplifying the po-
tential productivity of the gulf. And the nutrient load of the gulf is substantially supplemented by the freshwa-
ter— some 950 billion liters annually—from the sixty rivers flowing into it, of which the Saint John is the
largest. This great drainage basin collects waters from three American states and three Canadian provinces:
Massachusetts, New Hampshire, Maine, Nova Scotia, New Brunswick, and even a portion of Quebec. These
freshwaters, flowing downhill from a web of streams, ponds, lakes, and rivers, enrich the marine ecosystem
with a constant and critical supply of nutrients from the land. But it is the currents and tidal action that bring
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