Seamount

A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface (sea level), and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from the seafloor to 1,000-4,000 metres (3,000-13,000 ft) in height. They are defined by oceanographers as independent features that rise to at least 1,000 metres (3,281 ft) above the seafloor. The peaks are often found hundreds to thousands of metres below the surface, and are therefore considered to be within the deep sea. There are an estimated 100,000 seamounts across the globe, with only a few having been studied. Seamounts come in all shapes and sizes, and follow a distinctive pattern of growth, activity, and death. In recent years, several active seamounts have been observed, for example Loihi in the Hawaiian Islands.

Because of their abundance, seamounts are one of the most common oceanic ecosystems in the world. Interactions between seamounts and underwater currents, as well as their elevated position in the water, attract plankton, corals, fish, and marine mammals alike. Their aggregational effect has been noted by the commercial fishing industry, and many seamounts support extensive fisheries. There are ongoing concerns on the negative impact of fishing on seamount ecosystems, and well-documented cases of stock decline, for example with the orange roughy (Hoplostethus atlanticus). 95% of ecological damage is done by bottom trawling, which literally scrapes whole ecosystems off seamounts.

Because of their large numbers, many seamounts remain to be properly studied, and even mapped. Bathymetry and satellite altimetry are two technologies working to close the gap. There have been instances where naval vessels have collided with uncharted seamounts; for example, Muirfield Seamount is named after the ship that struck it in 1973. However, the greatest danger from seamounts are flank collapses; as they get older, extrusions seeping in the seamounts put pressure on their sides, causing landslides that have the potential to generate massive tsunamis.

Read more about SeamountGeography, Exploration, Deep-sea Mining, Dangers

Other articles related to "seamount, seamounts":

Louisville Seamount Chain
... The Louisville seamount chain is an underwater chain of over 70 seamounts in the Southwest Pacific Ocean ... One of the longest seamount chains on Earth, it stretches some 4,300 kilometres from the Pacific-Antarctic Ridge north west to the Tonga-Kermadec Trench, where it subducts under the Indo-Australian ...
Seamount - Dangers
... See also Landslide#Causing tsunamis and Landslide#Prehistoric submarine landslides Some seamounts have not been mapped and thus pose a navigational danger ... For instance, Muirfield Seamount is named after the ship that hit it in 1973 ... More recently, the submarine USS San Francisco ran into an uncharted seamount in 2005 at a speed of 35 knots (40.3 mph 64.8 km/h), sustaining serious damage and killing one seaman ...
Axial Seamount - History - Early History
... The first volcanoes along the Juan de Fuca ridge, including Axial Seamount, were detected in the 1970s by satellite altimetry ... Axial Seamount's proximity to the western coast and shallow depth make it one of the most easily accessible seamounts in the world, and its unique ... The first bathymetry of the seamount was compiled by the NOAAS Surveyor in 1981, as part of SeaBeam trials in the North Pacific ...
Symphurus Thermophilus - Biology and Ecology - Feeding
... thermophilus varies significantly from seamount to seamount, with the only constant being polychaete worms, which are most important for individuals on Daikoku and Volcano-1 Seamounts ... thermophilus on the Nikko Seamount is the alvinocaridid shrimp Opaepele loihi, and on the Kasuga-2 Seamount they eat mostly palaemonid shrimp ... By contrast, the fish at the Daikoku Seamount seem to be more active, opportunistic foragers they do not eat many crustaceans and have been observed scavenging on dying fish that ...
Stirni Seamount
... The Union Seamount is a seamount located in the Pacific Ocean off the coast of northern Vancouver Island, British Columbia, Canada ...