Seamounts or seamounts (English technical term: seamount ) are undersea mountains, about 1,000 to 4,000 meters high rising from the seabed, but the sea does not reach. Mostly it is submarine volcanoes.
Formation and development
Seamounts and similar Guyots arise at the divergent plate boundaries of the mid-ocean ridges or within an oceanic plate under the hot-spot volcanism. The movement of the oceanic crust in the course of Seafloor Spreading ( sea floor spreading ) the volcanoes lose contact with their Magmenquelle and Magmenförderung goes out.
Seamounts are characterized by very steep slopes and a relatively small extent in the dome area.
In contrast to Guyots seamounts protrude by definition do not have the sea beyond and therefore not subject to the erosive action of the surf. However, seamounts can develop into islands, as you saw in Surtsey and expects about at the Loihi seamount in Hawaii.
Seamounts are found in all oceans, especially near Mediterranean back as the mid-Atlantic ridge and hot spots. There are, for example, an unusual accumulation in the eastern North Atlantic.
At subduction zones, where one tectonic plate dives beneath the other, such as the so-called Pacific Ring of Fire, these volcanoes can form obstacles. The subducting plate will depend to some extent and this leads to violent earthquakes.
Examples of seamounts in the Pacific are in the Hawaiian - Emperor chain of islands in the Atlantic Ocean, the Gorringe Bank and the Mediterranean Ferdinandea and Marsili.
Flora and Fauna
Seamounts and their fauna have hardly been explored. The deep sea, prevails in the absolute darkness, but a large number of houses animal species, such as squid, such as the giant squid, but often characterized by low reproductive rates. In contrast to the surrounding ocean to seamounts are characterized by an increased incidence of organisms, as they project into the rich zooplankton zone around 1000 m depth, and here by its rocky surface colonization by sessile filter feeders (eg sponges, corals, brachiopods, which allow sea lilies and feather stars bryozoans ). When the crest of the sea mountains ranges in the upper light-flooded zone, even plants can grow on them. Especially large brown algae, whose collections are referred to as " Tangwälder ", use this habitat.
The residents at higher altitudes seamounts are in danger of being fished out and killed by fishing with huge bottom trawls.