Seamounts

Seamounts are submarine mountains that rise from the ocean floor but do not reach the surface. They are typically volcanic in origin, formed by magma from hotspots or volcanic activity along mid-ocean ridges as tectonic plates move.

Over time, erosion and subsidence can lower their peaks; when a seamount’s top is leveled by wave action and the structure sinks below sea level, it may become a guyot or tablemount.

Seamounts occur in all oceans and often form chains or clusters that trace past plate movements. The Hawaiian-Emperor seamount chain is a well-known example created as the Pacific Plate moved over a fixed hotspot. They vary in height from a few hundred to several thousand meters above the surrounding seafloor and can extend tens to hundreds of kilometers across.

Seamounts create localized habitats that support diverse deep-sea communities; currents and upwelling around seamounts can enhance productivity and sustain corals, sponges, fishes, and other organisms, including hydrothermal-vent–associated communities on some seamounts. Their isolation and complexity make them important for biodiversity studies and for understanding deep-sea ecology.

Seamounts are identified through bathymetric mapping, sonar, and remote sensing, and many remain poorly explored. They are of scientific interest for understanding plate tectonics and oceanography and pose considerations for fisheries management and potential mineral mining, due to vulnerabilities to overfishing and environmental disturbance.