Seamount
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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.
Seamounts are often found in groupings or submerged archipelagos, a classic example being the Emperor Seamounts, which are an extension of the Hawaiian Islands, which were formed millions of years ago by volcanism, and have since subsided to below sea level. The long chain of islands and seamounts, extending thousands of kilometres northwest from the Big Island demonstrates the movement of a plate over a volcanic hotspot.
Isolated seamounts and those without clear volcanic origins appear to be less common. In recent years, geologists have confirmed that a number of seamounts are active undersea volcanoes: Lo‘ihi in the Hawaiian Islands and Vailu‘ulu‘u in the Manu‘a Group (Samoa) are examples.
Seamounts often project upwards into shallower zones more hospitable to sea life, providing habitats for marine species that are not found on or around the surrounding deeper ocean bottom. In addition to simply providing physical presence in this zone, the seamount itself may deflect deep currents and create upwelling. This process can bring nutrients into the photosynthetic zone, producing an area of productivity in an otherwise desert-like open ocean. Seamounts may thus be vital stopping points for some migratory animals such as whales. Some recent research indicates whales may use such features as navigational aids.
See also
References
- Keating, B.H., Fryer, P., Batiza, R., Boehlert, G.W. (Eds.), 1987: Seamounts, islands and atolls. Geophys. Monogr. 43:319-334.
- Koslow, J.A. (1997). Seamounts and the ecology of deep-sea fisheries. Am. Sci. 85:168-176.
- Menard, H.W. (1964). Marine Geology of the Pacific. International Series in the Earth Sciences. McGraw-Hill, New York, 271 pp.
External links
- [SeamountsOnline], a database of seamount biology
- [Volcanic History of Seamounts in the Gulf of Alaska]
- [Hydrographic structure and circulation at the Great Meteor Seamount] showing an example of an isolated seamount and the formation of a submerged island of life.
- [Seamount Oasis]
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