Just like on land, there are vast mountains that lie deep beneath the ocean’s waters. Seamounts are underwater mountains that rise at least 3,300 feet (1,000 meters) from the surrounding seafloor, most of which include the remains of extinct volcanoes. These submarine mountains can be found in every ocean basin and serve an essential role in supporting biologically rich deep-sea ecosystems. Think of them like the underwater version of a coral reef or a kelp forest—critical foundation habitats where everything from deep-sea corals and sponges to commercially important fish and migratory species converge.
Several seamounts lie within the boundaries of your national marine sanctuaries, such as in Pāpahānaumokuākea, American Samoa, and Monterey Bay, which provide unique protections from 21st century challenges. Here are five reasons why seamounts are vital to our ocean and the national marine sanctuaries that safeguard them:
1. Seamounts Support Many Deep-Sea Species and Habitats
Seamounts are like ‘oases’ in the deep sea, serving as a gathering space for a variety of different organisms. In the cold, dark, and highly pressurized abyss of the sea, seamounts are biodiversity hotspots that are often teeming with life. As the slope of the seamount increases, deep-sea currents are forced upward, bringing nutrient-rich water that attracts a wide variety of species—from plankton to lobsters, and even sharks and whales. This productivity benefits the entire water column, not just the deep sea.
Corals and sponges serve as key species in the ecosystem, offering both nourishment for predators and shelter that supports a wide variety of marine life, including crabs, squat lobsters, and sea stars. The rugged terrain of seamounts creates small crevices that provide refuge for creatures like fish and octopuses.
read more at sanctuaries.noaa.gov.
