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Images: Coral Gardens in the Dark Depths

TOUCHED BY A COLD HAND—A colonial soft coral (octocoral) pulls in its small, whitish polyps upon contact with the manipulator hand of the remotely operated vehicle Hercules. This coral (Paragorgia) is called "bubblegum coral" because of its color and bulbous branch ends. It is common on the New England Seamounts. (Deep-sea coral photos courtesy "Mountains in the Sea" scientific party, NOAA, and the Institute for Exploration)

VENERABLE INVERTEBRATES—Deep-sea stony corals can attain great ages, and the hard skeletons of dead ones sometimes form mounds, tens of meters long and high, which support living colonies. This yellow stony coral has soft corals, feather stars, and brittle stars as neighbors. (Deep-sea coral photos courtesy "Mountains in the Sea" scientific party, NOAA, and the Institute for Exploration.)

HOT COLOR IN THE BLACK DEPTHS—A pink bushy black coral, a white tree-like soft coral behind it, and a bright yellow sponge share a rocky seamount slope far below the reach of sunlight. (Deep-sea coral photos courtesy "Mountains in the Sea" scientific party, NOAA, and the Institute for Exploration.)

CLEAN SLATES—Researchers placed blocks of basalt on a seamount?s rocky surface to measure if larvae from other communities will settle near these two colonies of corals (Paragorgia). The blocks, next to a numbered marker and attached to yellow lines for retrieval, have been in place for a year. (Deep-sea coral photos courtesy "Mountains in the Sea" scientific party, NOAA, and the Institute for Exploration.)

A HARD-ROCK FOUNDATION—Corals require a hard surface to grow on, like this circular outcropping of seafloor basalt. A red crab is free to roam at will over sand and rock. (Deep-sea coral photos courtesy "Mountains in the Sea" scientific party, NOAA, and the Institute for Exploration.)

NO VISIBLE MEANS OF SUPPORT—Black corals have many forms and colors. This unbranched "black whip coral," attached to the bottom, is supported only by the water. (Deep-sea coral photos courtesy "Mountains in the Sea" scientific party, NOAA, and the Institute for Exploration.)

A CORAL LINE—A line of deep-sea corals recedes into darkness. From bottom left to top right: white, bushy soft corals, a bright orange black coral, a branched soft coral like a bare tree, and white, twisted, branchless bamboo corals. Sharing center stage in front are (left to right) a dark, bottlebrush-shaped black coral, a red soft coral, and purple crinoids (relatives of sea stars). (Deep-sea coral photos courtesy "Mountains in the Sea" scientific party, NOAA, and the Institute for Exploration.)

FRAGILE OASES—Rising abruptly from the seafloor, seamounts are home to fragile ecosystems often dominated by corals. They are vulnerable to damage by fishing gear and are believed to be slow to recover. Many scientists recommend making them protected areas. The New England Seamount chain stretches from the coast toward the middle of the North Atlantic.

CALCULATING CORAL AGES—By measuring the amount of a naturally occurring lead isotope (with a known half-life) in this section of a Paragorgia trunk, scientists can determine how old the coral it is.

MIDNIGHT GARDEN—A deep coral community grows on volcanic rock in the New England Seamount chain. It includes an abundance of invertebrate animals, including pink, white, and orange soft corals, red-orange sea stars, and a multitude of different light-colored sponges. (Deep-sea coral photos courtesy "Mountains in the Sea" scientific party, NOAA, and the Institute for Exploration.)

BLACK BUT ORANGE—Black corals can have several growth forms and external tissue colors. This one, bright orange and feathery, is nearly 6 feet tall. Their hard black internal skeletons are prized for jewelry. (Deep-sea coral photos courtesy "Mountains in the Sea" scientific party, NOAA, and the Institute for Exploration.)