Darwin Mounds
Encyclopedia
Darwin Mounds describes a vast field of undersea sand mounds situated off the north west coast of Scotland, first discovered in May 1998, they provide a unique habitat for ancient deep water coral
reefs. 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 evolution
ary theorist Charles Darwin
.
Located around 1,000 m (3,280 feet) below the surface of the North Atlantic ocean, approximately 100 nautical miles (185.2 km) north-west of Cape Wrath
, the north-west tip of mainland Scotland. There are hundreds of mounds in the field, which in total cover approximately 100 km². Individual mounds are typically circular, up to 5 m high and 100 m 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.
es'. 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 located upon the mounds, are especially fragile. Unlike shallow-water coral reef
s, 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 cm and are often very fragile. The corals themselves provide a habitat for a wide diversity of other marine life including sponges, worm
s, crustacean
s and molluscs. Among these starfish, sea urchin
s and crab
s. Various fish have been observed, including blue ling, roundnose grenadier, and the orange roughy
.
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 one metre square were found in the nets of French trawling vessels that had been scraping the seabed one kilometre down. It is known that much coral was destroyed by these nets and the mounds themselves in some areas were found to be scrapped 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 have included side-scan sonar
, stills and video cameras and piston corers. However, we will never know the entirety of what was lost during the period of time when the heavy netted fishing trawlers were operating above the mounds. On 22 March 2004 EU Fisheries Ministers in Brussels finally agreed to give permanent protection to Scotland's unique cold-water coral reefs, recognising the Darwin Mounds as an important habitat. As of 2004 deep-water bottom trawling in the area has been made illegal.
Deep water coral
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 where water temperatures may be as cold as 4°C...
reefs. 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
Research vessel
A research vessel is a ship designed and equipped to carry out research at sea. Research vessels carry out a number of roles. Some of these roles can be combined into a single vessel, others require a dedicated vessel...
, itself named for the eminent naturalist and evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
ary theorist Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
.
Located around 1,000 m (3,280 feet) below the surface of the North Atlantic ocean, approximately 100 nautical miles (185.2 km) north-west of Cape Wrath
Cape Wrath
Cape Wrath is a cape in Sutherland, Highland, in northern Scotland. It is the most northwesterly point on the island of Great Britain. The land between the Kyle of Durness and the lighthouse that is situated right at the tip, is known as the Parph, two hundred and seven square kilometers of...
, the north-west tip of mainland Scotland. There are hundreds of mounds in the field, which in total cover approximately 100 km². Individual mounds are typically circular, up to 5 m high and 100 m 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.
Composition
The mounds are mostly sand, currently interpreted as 'sand volcanoSand volcano
A sand volcano or sand blow is a cone of sand formed by the ejection of sand onto a surface from a central point. The sand builds up as a cone with slopes at the sand's angle of repose. A crater is commonly seen at the summit...
es'. 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
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
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
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
species. The mounds are also unusual in that Lophelia pertusa
Lophelia pertusa
Lophelia pertusa is a species of cold-water coral which grows in the deep waters throughout the North Atlantic ocean, as well as parts of the Caribbean Sea and Alboran Sea. L...
, 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 located upon the mounds, are especially fragile. Unlike shallow-water coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
s, they are not adapted to cope with minor disturbances such as wave action.
The mounds also support significant populations of the xenophyophore
Xenophyophore
Xenophyophores are marine protozoa, giant single-celled organisms found throughout the world's oceans, at depths of up to 10,641 meters . Xenophyophores are found in the greatest numbers on the abyssal plains of the deep ocean. They were first described as sponges in 1889, then as testate...
Syringammina fragilissima
Syringammina fragilissima
Syringammina fragilissima is a xenophyophore found off the coast of Scotland, near Rockall. It is the largest single-celled organism known, at up to across...
. 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 cm and are often very fragile. The corals themselves provide a habitat for a wide diversity of other marine life including sponges, worm
Worm
The term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical...
s, crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s and molluscs. Among these starfish, sea urchin
Sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...
s and crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s. Various fish have been observed, including blue ling, roundnose grenadier, and the orange roughy
Orange roughy
The orange roughy, red roughy, or deep sea perch, Hoplostethus atlanticus, is a relatively large deep-sea fish belonging to the slimehead family . The Marine Conservation Society has categorized orange roughy as vulnerable to exploitation...
.
Conservation efforts
On 23 October 2001, UK Minister Margaret BeckettMargaret Beckett
Margaret Mary Beckett is a British Labour Party politician who has been the Member of Parliament for Derby South since 1983, rising to become the Deputy Leader of the Labour Party under John Smith, from 18 July 1992 to 12 May 1994, and briefly serving as Leader of the Party following Smith's death...
made a commitment at WWF's
World Wide Fund for Nature
The World Wide Fund for Nature is an international non-governmental organization working on issues regarding the conservation, research and restoration of the environment, formerly named the World Wildlife Fund, which remains its official name in Canada and the United States...
Oceans Recovery Summit in Edinburgh
Edinburgh
Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...
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
Bottom trawling
Bottom trawling is trawling along the sea floor. It is also often referred to as "dragging".The scientific community divides bottom trawling into benthic trawling and demersal 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 one metre square were found in the nets of French trawling vessels that had been scraping the seabed one kilometre down. It is known that much coral was destroyed by these nets and the mounds themselves in some areas were found to be scrapped 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 have included side-scan sonar
Side-scan sonar
Side-scan sonar is a category of sonar system that is used to efficiently create an image of large areas of the sea floor...
, stills and video cameras and piston corers. However, we will never know the entirety of what was lost during the period of time when the heavy netted fishing trawlers were operating above the mounds. On 22 March 2004 EU Fisheries Ministers in Brussels finally agreed to give permanent protection to Scotland's unique cold-water coral reefs, recognising the Darwin Mounds as an important habitat. As of 2004 deep-water bottom trawling in the area has been made illegal.
External links
- "Biogenic reefs - cold water corals", Joint Nature Conservation Committee, U.K. government, retrieved 8 December 2007
- "Trawler ban to protect reefs, BBC News, 20 August 2003