When most of us think of coral, we picture a scene not unlike that found in Pixar’s Finding Nemo: a vast multicolored reef in the warm shallow waters of the tropics, inhabited by a multitude of equally colorful fish. But did you know that many intricate and colorful species of coral can be found right here in our own New England waters? Growing along the ridges of underwater canyons and seamounts off the Atlantic coast, the New England version of a tropical reef plays host to our own aquatic flora and fauna, more suited to the chilly waters of the northwest Atlantic.
Though they resemble undersea plants, corals are in fact colonies of tiny, soft-bodied invertebrates whose secreted exoskeletons form, over time, the large and intricate structures that we recognize as coral. In the warm waters of the tropics, groups of these exoskeletoned colonies form extensive reefs in the clear, shallow waters close to the shore.
Though snorkelers may appreciate the clear waters of the tropics, the water is so clear in these areas because it contains few nutrients or plankton. Very little mixing of the water column occurs in these uniformly warm waters, so nutrients remain trapped on the bottom of the sea, preventing the multiplication of plankton, and leaving the water empty of food. As a result, tropical corals get their nutrients through a symbiotic relationship with photosynthetic algae, which grows inside the coral and lends it energy from the sun. Large animals like whales, however, are unable to sustain themselves by hosting algae. Instead, whales like humpbacks and right whales breed in tropical waters but return to New England to feed in the summer. The constantly mixing warm and cold waters of New England bring nutrients to the surface, encouraging plankton growth, and are thus a veritable soup of life. New England corals enjoy this soup just as much as the whales do, and most of them filter feed instead of relying on algae to do the work for them.
A striking purple coral, Clavularia sp., seen in Nygren Canyon. Image via NOAA/Okeanos Explorer
New England corals live not in the near-shore shallows but along underwater canyons and seamounts. Last summer, NOAA’s Okeanos mission documented some of the wide array of marine life in the Northeast’s canyons, including Oceanographer Canyon, a deep underwater channel that cuts into the southern edge of Georges Bank. You can see images and video from the mission here. The seamounts are part of the New England Seamount Chain and often rise to within 100 feet of the ocean surface, ensuring a rich habitat for undersea creatures due to the high concentration of particulates in the water and the nearness of sunlight.
Unfortunately, cold water corals grow slowly and are very susceptible to the effects of trawling, which is why Fishery Management Councils along the east coast have begun to take action to protect areas like canyons and seamounts with rich deep-sea coral populations.
New England’s corals are surrounded by towering kelp forests, fish and mammals of all kinds, and even sea turtles. So if you’ve ever wanted to dive the Great Barrier Reef, but balked at the idea of that plane ticket to Australia, consider exploring the underwater scenery right in our own backyard!