Seamounts: Underwater Oases

Colorful corals and brittlestars on Manning Seamount off the New England coast.

Colorful corals and brittlestars on Manning Seamount off the New England coast.

Credit: 

Mountains in the Sea Research Group/NOAA/IFE

Thousands of seamounts—most of them undersea volcanoes—tower above the muddy seafloor. They provide something hard to come by in the deep ocean: a solid surface to cling to. Corals, sponges, and other marine animals attach themselves in dense colonies to seamount slopes. As the animals grow and reproduce, they create three-dimensional structures that provide homes for other creatures. Crabs, sea lilies, and brittle stars climb aboard to gather food. Currents well up and swirl around, serving up a constant supply of nutrients and plankton. There may be 30,000 seamounts in the Pacific Ocean alone. Less than 1% have been explored. Many are separated from one another by long distances. Are seamounts like islands, each with its own unique fauna? That and many other questions remain to be answered.

Photograph of an orange many-armed sea star on an erect delicately-branched coral in a dark sea.

A bright orange sea star (Novodinia antillensis) clings to a white soft coral (Paragorgia sp.) at Manning Seamount, New England Seamount Chain.

Credit: 

Mountains in the Sea Research Group/NOAA/IFE

The New England Seamount Chain is the longest in the North Atlantic Ocean and includes peaks of more than 30 extinct volcanoes.

The New England Seamount Chain is the longest in the North Atlantic Ocean and includes peaks of more than 30 extinct volcanoes.

Credit: 

Adapted from Christopher Small, Lamont Doherty Earth Observatory, Columbia University