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Darwin Mounds is a large field of undersea sand mounds situated off the north west coast of Scotland [1] that were first discovered in May 1998. They provide a unique habitat for ancient deep water coral reefs and were found using remote sensing techniques during surveys funded by the oil industry and steered by the joint industry and United Kingdom government group the Atlantic Frontier Environment Network (AFEN) (Masson and Jacobs 1998). The mounds were named after the research vessel, itself named for the eminent naturalist and evolutionary theorist Charles Darwin.
The mounds are about 1,000 metres (3,300 ft) below the surface of the North Atlantic ocean, approximately 100 nautical miles (190 km) north-west of Cape Wrath, the north-west tip of mainland Scotland. [2] There are hundreds of mounds in the field, which in total cover approximately 100 square kilometres (39 sq mi). Individual mounds are typically circular, up to 5 metres (16 ft) high and 100 metres (330 ft) wide. Most of the mounds are also distinguished by the presence of an additional feature referred to as a 'tail'. The tails are of a variable extent and may merge with others, but are generally a teardrop shape and are orientated south-west of the mound. The mound-tail feature of the Darwin Mounds is apparently unique globally. [3]
The mounds are mostly sand, currently interpreted as "sand volcanoes". These features are caused when fluidised sand "de-waters" and the fluid bubbles up through the sand, pushing the sediment up into a cone shape. Sand volcanoes are common in the Devonian fossil record in UK, and in seismically active areas of the planet. In this case, tectonic activity is unlikely; some form of slumping on the south-west side of the undersea (Wyville-Thomson) Ridge being a more likely cause. The tops of the mounds have living stands of Lophelia and blocky rubble (interpreted as coral debris). The mounds provide one of the largest known northerly cold-water habitats for coral species. The mounds are also unusual in that Lophelia pertusa, a cold water coral, appears to be growing on sand rather than a hard substratum. Prior to research on the mounds in 2000, it was thought that Lophelia required a hard substratum for attachment.
The deep-water coral systems on the mounds are especially fragile. Unlike shallow-water coral reefs, they are not adapted to cope with minor disturbances such as wave action. The mounds also support significant populations of the xenophyophore Syringammina fragilissima . This is a giant single-celled organism (a protozoan) that is widespread in deep waters, but occurs in particularly high densities on the mounds and the tails. Individual xenophyophores can grow to be larger than 20 centimetres (7.9 in) and are often very fragile. The corals themselves provide a habitat for a wide diversity of other marine life including sponges, worms, crustaceans and molluscs. Among these starfish, sea urchins and crabs. Various fish have been observed, including blue ling, roundnose grenadier, and the orange roughy.
On 23 October 2001, UK Minister Margaret Beckett made a commitment at WWF's Oceans Recovery Summit in Edinburgh to protect the Darwin Mounds. The summit launched the Edinburgh Declaration, targeting politicians and marine stakeholders alike to sign up to action to safeguard the seas. Deep water bottom trawling had been occurring in the area, with nets as heavy as one tonne dragged across the sea floor. Researcher Jason Hall-Spencer of the University of Glasgow had found pieces of coral at least 4,500 years old in the nets of trawlers operating off the coast of Ireland and Scotland. Pieces of coral up to 1 square metre (11 sq ft) were found in the nets of French trawling vessels that had been scraping the seabed 1 kilometre (0.6 mi) down. It is known that much coral was destroyed by these nets and the mounds themselves in some areas were found to be scraped and flattened. The mounds are ancient structures, and this damage is permanent.
After the discovery of the mounds, three well-documented surveys of the area were undertaken, one in June 1998 (Bett 1999), August 1999 (Bett & Jacobs 2000,) and twice during summer 2000 (B. Bett, pers. comm.). Instruments deployed during the studies included side-scan sonar, stills and video cameras and piston corers. However, the entirety of what was lost to heavy-netted fishing trawlers remains unknown. On 22 March 2004 EU Fisheries Ministers in Brussels agreed to give permanent protection to the United Kingdom's unique cold-water coral reefs, recognising the Darwin Mounds as an important habitat. In 2004 deep-water bottom trawling in the area was made illegal.
The Skagerrak is a strait running between the Jutland peninsula of Denmark, the southeast coast of Norway and the west coast of Sweden, connecting the North Sea and the Kattegat sea.
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic (non-living) processes such as deposition of sand or wave erosion planing down rock outcrops. However, reefs such as the coral reefs of tropical waters are formed by biotic (living) processes, dominated by corals and coralline algae. Artificial reefs such as shipwrecks and other man-made underwater structures may occur intentionally or as the result of an accident, and are sometimes designed to increase the physical complexity of featureless sand bottoms to attract a more diverse range of organisms. Reefs are often quite near to the surface, but not all definitions require this.
Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different species of fishes or sometimes targeted species. Trawls are often called towed gear or dragged gear.
Anthozoa is a class of marine invertebrates which includes the sea anemones, stony corals and soft corals. Adult anthozoans are almost all attached to the seabed, while their larvae can disperse as part of the plankton. The basic unit of the adult is the polyp; this consists of a cylindrical column topped by a disc with a central mouth surrounded by tentacles. Sea anemones are mostly solitary, but the majority of corals are colonial, being formed by the budding of new polyps from an original, founding individual. Colonies are strengthened by calcium carbonate and other materials and take various massive, plate-like, bushy or leafy forms.
Bottom trawling is trawling along the seafloor. It is also referred to as "dragging". The scientific community divides bottom trawling into benthic trawling and demersal trawling. Benthic trawling is towing a net at the very bottom of the ocean and demersal trawling is towing a net just above the benthic zone. Bottom trawling can be contrasted with midwater trawling, where a net is towed higher in the water column. Midwater trawling catches pelagic fish such as anchovies and mackerel, whereas bottom trawling targets both bottom-living fish (groundfish) and semi-pelagic species such as cod, squid, shrimp, and rockfish.
Lophelia pertusa, the only species in the genus Lophelia, is a cold-water coral that grows in the deep waters throughout the North Atlantic ocean, as well as parts of the Caribbean Sea and Alboran Sea. Although L. pertusa reefs are home to a diverse community, the species is extremely slow growing and may be harmed by destructive fishing practices, or oil exploration and extraction.
The Miami Terrace Reef is a coral reef off the coast of Florida stretching from South Miami to Boca Raton, in the Atlantic Ocean. It lies in depths of 650 to 2,000 feet on top of a geological formation known as the Miami Terrace, a 40-mile (65 km) long shelf about 15 miles (24 km) off shore. Much of the platform remains unexplored, and new portions of the reef are still being discovered. University of Miami researchers discovered new reef sites there in December 2005.
The Bear Seamount is a guyot or flat-topped underwater volcano in the Atlantic Ocean. It is the oldest of the New England Seamounts, which was active more than 100 million years ago. It was formed when the North American Plate moved over the New England hotspot. It is located inside the Northeast Canyons and Seamounts Marine National Monument, which was proclaimed by President of the United States Barack Obama to protect the seamount's biodiversity.
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Sponge reefs are reefs formed by Hexactinellid sponges, which have a skeleton made of silica, and are often referred to as glass sponges. Such reefs are now very rare, and found only in waters off the coast of British Columbia, Washington and southern Alaska. Recently sponge reefs were identified within the strait of Georgia and Howe sound close to Vancouver. Although common in the late Jurassic period, reef-building sponges were believed to have gone extinct during or shortly after the Cretaceous period, until the existing reefs were discovered Queen Charlotte sound in 1987–1988 – hence these sometimes being dubbed living fossils.
The habitat of deep-water corals, also known as cold-water corals, extends to deeper, darker parts of the oceans than tropical corals, ranging from near the surface to the abyss, beyond 2,000 metres (6,600 ft) where water temperatures may be as cold as 4 °C (39 °F). Deep-water corals belong to the Phylum Cnidaria and are most often stony corals, but also include black and thorny corals and soft corals including the Gorgonians. Like tropical corals, they provide habitat to other species, but deep-water corals do not require zooxanthellae to survive.
This is a glossary of terms used in fisheries, fisheries management and fisheries science.
Destructive fishing practices are practices that easily result in irreversible damage to aquatic habitats and ecosystems. Many fishing techniques can be destructive if used inappropriately, but some practices are particularly likely to result in irreversible damage. These practices are mostly, though not always, illegal. Where they are illegal, they are often inadequately enforced.
Hotspot Ecosystem Research and Man's Impact On European Seas (HERMIONE) is an international multidisciplinary project, started in April 2009, that studies deep-sea ecosystems. HERMIONE scientists study the distribution of hotspot ecosystems, how they function and how they interconnect, partially in the context of how these ecosystems are being affected by climate change and impacted by humans through overfishing, resource extraction, seabed installations and pollution. Major aims of the project are to understand how humans are affecting the deep-sea environment and to provide policy makers with accurate scientific information, enabling effective management strategies to protect deep sea ecosystems. The HERMIONE project is funded by the European Commission's Seventh Framework Programme, and is the successor to the HERMES project, which concluded in March 2009.
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