seamount

A seamount is an underwater mountain rising from the ocean floor that does not reach the surface. It is typically defined as an isolated elevation at least 1,000 meters high relative to the surrounding seafloor. Seamounts are most commonly volcanic in origin, formed by magma rising at hotspots, along mid-ocean ridges, or within volcanic arcs. After volcanic activity subsides or as the tectonic plate moves, the summit may subside, and some seamounts become flat-topped due to erosion and carbonate buildup; such flat-topped forms are known as guyots or tablemounts.

Geology and morphology vary among seamounts. Some remain cone-shaped volcanic peaks rising abruptly from the seafloor, while others erode and subside into broad, flattened tops. The composition is often basaltic, though older seamounts can host diverse rock types depending on their history. The isolation of seamounts in the deep ocean creates unique habitats and localized oceanographic effects.

Ecologically, seamounts are biodiversity hotspots. Persistent currents and upwelling deliver nutrients that support rich plankton communities, which in turn sustain corals, sponges, and a variety of fish and invertebrates. Many seamount communities exhibit high species richness and endemism, making them important for research and conservation.

Mapping and exploration rely on acoustic techniques such as multibeam sonar and satellite altimetry, along with direct sampling from submersibles or remotely operated vehicles. Seamounts can influence navigation and submarine operations and are often the focus of fisheries management and marine protected-area programs due to their ecological significance and vulnerability to disturbance.