160-736: Brent Spar , known as Brent "E", was a North Sea oil storage and tanker loading buoy in the Brent oilfield , operated by Shell UK . With the completion of a pipeline connection to the oil terminal at Sullom Voe in Shetland , the storage facility had continued in use, but by 1991, was considered to be of no further value. Brent Spar became an issue of public concern in 1995, when the British government announced its support for Shell's application for its disposal in deep Atlantic waters at North Feni Ridge (approximately 160 mi (250 km) from
320-447: A murre colony. In most seabird colonies, several different species will nest on the same colony, often exhibiting some niche separation . Seabirds can nest in trees (if any are available), on the ground (with or without nests ), on cliffs, in burrows under the ground and in rocky crevices. Competition can be strong both within species and between species, with aggressive species such as sooty terns pushing less dominant species out of
480-401: A wreck . Seabirds have had a long association with both fisheries and sailors , and both have drawn benefits and disadvantages from the relationship. Fishermen have traditionally used seabirds as indicators of both fish shoals , underwater banks that might indicate fish stocks, and of potential landfall. In fact, the known association of seabirds with land was instrumental in allowing
640-601: A "Scottish", or "UK" problem, and neglecting to think of the effect which it would have on their image in the wider world. The final cost of the Brent Spar operation to Shell was between £60M and £100M, when loss of sales were considered. Although Shell and the offshore industry consider that Brent Spar did not set a precedent for disposal of facilities in the future, signatory nations of the OSPAR conventions have since agreed that oil facilities should be disposed of onshore, so it
800-571: A Tuath . The North Sea has provided waterway access for commerce and conquest. Many areas have access to the North Sea because of its long coastline and the European rivers that empty it. There is little documentary evidence concerning the North Sea before the Roman conquest of Britain in 43 CE, however, archaeological evidence reveals the diffusion of cultures and technologies from across or along
960-738: A challenge to their dominance of the North Sea until the 20th century. Tensions in the North Sea were again heightened in 1904 by the Dogger Bank incident . During the Russo-Japanese War , several ships of the Russian Baltic Fleet, which was on its way to the Far East, mistook British fishing boats for Japanese ships and fired on them, and then upon each other, near the Dogger Bank, nearly causing Britain to enter
1120-618: A clade, the Aequornithes either became seabirds in a single transition in the Cretaceous or some lineages such as pelicans and frigatebirds adapted to sea living independently from freshwater-dwelling ancestors. In the Paleogene both pterosaurs and marine reptiles became extinct, allowing seabirds to expand ecologically. These post-extinction seas were dominated by early Procellariidae , giant penguins and two extinct families ,
1280-543: A colony. Eggers from San Francisco took almost half a million eggs a year from the Farallon Islands in the mid-19th century, a period in the islands' history from which the seabird species are still recovering. Both hunting and egging continue today, although not at the levels that occurred in the past, and generally in a more controlled manner. For example, the Māori of Stewart Island / Rakiura continue to harvest
1440-405: A common occurrence, with 13 of 14 North Sea oil rigs examined having L. pertusa colonies. The authors of the original work suggested that it may be better to leave the lower parts of such structures in place — a suggestion opposed by Greenpeace campaigner Simon Reddy, who compared it to "[dumping] a car in a wood – moss would grow on it, and if I was lucky a bird may even nest in it. But this
1600-486: A fashion similar to grebes and loons (using its feet to move underwater) but had a beak filled with sharp teeth. Flying Cretaceous seabirds do not exceed wingspans of two meters; any sizes were taken by piscivorous pterosaurs . While Hesperornis is not thought to have left descendants, the earliest modern seabirds also occurred in the Cretaceous, with a species called Tytthostonyx glauconiticus , which has features suggestive of Procellariiformes and Fregatidae. As
1760-971: A large number of non-governmental organizations (including BirdLife International , the American Bird Conservancy and the Royal Society for the Protection of Birds ). This led to the Agreement on the Conservation of Albatrosses and Petrels , a legally binding treaty designed to protect these threatened species, which has been ratified by thirteen countries as of 2021 (Argentina, Australia, Brazil, Chile, Ecuador, France, New Zealand, Norway, Peru, South Africa, Spain, Uruguay, United Kingdom). Many seabirds are little studied and poorly known because they live far out at sea and breed in isolated colonies. Some seabirds, particularly
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#17327753272831920-504: A limited food supply, which is also normal in deep water communities. The final conclusions of FRS were that abundance and diversity were greater than had been expected, especially in the North Feni Ridge area, however the limited extent of sampling precluded detailed analysis of data for the entire area. On the basis of the data which FRS gathered, there was little to choose between the three potential disposal areas. Analysis of
2080-570: A lineage— Eurypygimorphae —that is a sister group to the Aequornithes. Seabirds, by virtue of living in a geologically depositional environment (that is, in the sea where sediments are readily laid down), are well represented in the fossil record. They are first known to occur in the Cretaceous period, the earliest being the Hesperornithiformes , like Hesperornis regalis , a flightless loon-like seabird that could dive in
2240-587: A million birds have been recorded, both in the tropics (such as Kiritimati in the Pacific ) and in the polar latitudes (as in Antarctica ). Seabird colonies occur exclusively for the purpose of breeding; non-breeding birds will only collect together outside the breeding season in areas where prey species are densely aggregated. Seabird colonies are highly variable. Individual nesting sites can be widely spaced, as in an albatross colony, or densely packed as with
2400-414: A place for returning mates to reunite, and reduces the costs of prospecting for a new site. Young adults breeding for the first time usually return to their natal colony, and often nest close to where they hatched. This tendency, known as philopatry , is so strong that a study of Laysan albatrosses found that the average distance between hatching site and the site where a bird established its own territory
2560-438: A reduced capacity for powered flight and are dependent on a type of gliding called dynamic soaring (where the wind deflected by waves provides lift) as well as slope soaring. Seabirds also almost always have webbed feet , to aid movement on the surface as well as assisting diving in some species. The Procellariiformes are unusual among birds in having a strong sense of smell , which is used to find widely distributed food in
2720-461: A smaller layer of air (compared to other diving birds) but otherwise soak up water. This allows them to swim without fighting the buoyancy that retaining air in the feathers causes, yet retain enough air to prevent the bird losing excessive heat through contact with water. The plumage of most seabirds is less colourful than that of land birds, restricted in the main to variations of black, white or grey. A few species sport colourful plumes (such as
2880-575: A source of increasing concern to conservationists. The bycatch of seabirds entangled in nets or hooked on fishing lines has had a big impact on seabird numbers; for example, an estimated 100,000 albatrosses are hooked and drown each year on tuna lines set out by long-line fisheries. Overall, many hundreds of thousands of birds are trapped and killed each year, a source of concern for some of the rarest species (for example, only about 2,000 short-tailed albatrosses are known to still exist). Seabirds are also thought to suffer when overfishing occurs. Changes to
3040-717: A vast merchant marine, a large fishing fleet, powerful navy, and sophisticated financial markets made the Dutch the ascendant power in the North Sea, to be challenged by an ambitious England. This rivalry led to the first three Anglo-Dutch Wars between 1652 and 1673, which ended with Dutch victories. After the Glorious Revolution in 1688, the Dutch prince William ascended to the English throne. With unified leadership, commercial, military, and political power began to shift from Amsterdam to London. The British did not face
3200-403: A vast ocean, and help distinguish familiar nest odours from unfamiliar ones. Salt glands are used by seabirds to deal with the salt they ingest by drinking and feeding (particularly on crustaceans ), and to help them osmoregulate . The excretions from these glands (which are positioned in the head of the birds, emerging from the nasal cavity ) are almost pure sodium chloride . With
3360-400: A very variable prey source); this may be a reason why it arises more frequently in seabirds. There are other possible advantages: colonies may act as information centres, where seabirds returning to the sea to forage can find out where prey is by studying returning individuals of the same species. There are disadvantages to colonial life, particularly the spread of disease. Colonies also attract
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#17327753272833520-536: A volume of 54,000 cubic kilometres (13,000 cu mi). Around the edges of the North Sea are sizeable islands and archipelagos , including Shetland , Orkney , and the Frisian Islands . The North Sea receives freshwater from a number of European continental watersheds, as well as the British Isles . A large part of the European drainage basin empties into the North Sea, including water from
3680-458: A year, unless they lose the first (with a few exceptions, like the Cassin's auklet ), and many species (like the tubenoses and sulids ) will only lay one egg a year. Care of young is protracted, extending for as long as six months, among the longest for birds. For example, once common guillemot chicks fledge , they remain with the male parent for several months at sea. The frigatebirds have
3840-620: Is 17 °C (63 °F) in the summer and 6 °C (43 °F) in the winter. The average temperatures have been trending higher since 1988, which has been attributed to climate change . Air temperatures in January range on average between 0 and 4 °C (32 and 39 °F) and in July between 13 and 18 °C (55 and 64 °F). The winter months see frequent gales and storms. The salinity averages between 34 and 35 grams per litre (129 and 132 g/US gal) of water. The salinity has
4000-562: Is a major fishery . The coast is a popular destination for recreation and tourism in bordering countries, and a rich source of energy resources, including wind and wave power . The North Sea has featured prominently in geopolitical and military affairs, particularly in Northern Europe , from the Middle Ages to the modern era. It was also important globally through the power northern Europeans projected worldwide during much of
4160-466: Is a series of asymmetrical trenches between 20 and 30 kilometres (12 and 19 mi) long, one and two kilometres (0.6 and 1.2 mi) wide and up to 230 metres (750 ft) deep. Other areas which are less deep are Cleaver Bank , Fisher Bank and Noordhinder Bank . The International Hydrographic Organization defines the limits of the North Sea as follows: On the Southwest. A line joining
4320-526: Is also home to marine mammals. Common seals , grey seals , and harbour porpoises can be found along the coasts, at marine installations, and on islands. The very northern North Sea islands such as the Shetland Islands are occasionally home to a larger variety of pinnipeds including bearded , harp , hooded and ringed seals , and even walrus . North Sea cetaceans include various porpoise , dolphin and whale species. Plant species in
4480-780: Is bounded by the Orkney Islands and east coast of Great Britain to the west and the northern and central European mainland to the east and south, including Norway , Denmark , Germany , the Netherlands , Belgium , and France . In the southwest, beyond the Straits of Dover , the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via
4640-399: Is difficult to see how this does not set a precedent. Shell claimed that spending such an amount to protect a small area of remote, low resource value, deep sea was pointless and this money could be much more constructively spent. The overestimation of the contents of the Brent Spar damaged the credibility of Greenpeace in their wider campaigns. They were criticised in an editorial column in
4800-407: Is energetically inefficient in warmer waters. With their poor flying ability, many wing-propelled pursuit divers are more limited in their foraging range than other guilds. Gannets , boobies , tropicbirds , some terns, and brown pelicans all engage in plunge diving, taking fast-moving prey by diving into the water from the flight. Plunge diving allows birds to use the energy from the momentum of
4960-642: Is inconclusive. Some plunge divers (as well as some surface feeders) are dependent on dolphins and tuna to push shoaling fish up towards the surface. This catch-all category refers to other seabird strategies that involve the next trophic level up. Kleptoparasites are seabirds that make a part of their living stealing food of other seabirds. Most famously, frigatebirds and skuas engage in this behaviour, although gulls, terns and other species will steal food opportunistically. The nocturnal nesting behaviour of some seabirds has been interpreted as arising due to pressure from this aerial piracy. Kleptoparasitism
Brent Spar - Misplaced Pages Continue
5120-703: Is not justification to fill our forests with disused cars". According to a poll of 1000 adults carried out by Opinion Leader Research on 26 January 1996 on behalf of Greenpeace, a majority of the British public were aware of the Brent Spar (57%). Of these, 57% were opposed to the dumping of Brent Spar in the Atlantic, and 32% were in favour of it. Although Shell had carried out an environmental impact assessment in full accordance with existing legislation, they had severely underestimated strength of public opinion. Shell were particularly criticised for having thought of this as
5280-545: Is not thought to play a significant part of the diet of any species, and is instead a supplement to food obtained by hunting. A study of great frigatebirds stealing from masked boobies estimated that the frigatebirds could at most obtain 40% of the food they needed, and on average obtained only 5%. Many species of gull will feed on seabird and sea mammal carrion when the opportunity arises, as will giant petrels . Some species of albatross also engage in scavenging: an analysis of regurgitated squid beaks has shown that many of
5440-402: Is often a problem as well—visitors, even well-meaning tourists, can flush brooding adults off a colony, leaving chicks and eggs vulnerable to predators. The build-up of toxins and pollutants in seabirds is also a concern. Seabirds, being apex predators , suffered from the ravages of the insecticide DDT until it was banned; DDT was implicated, for example, in embryo development problems and
5600-699: Is recorded to have killed more than 100,000 people. In 1362, the Second Marcellus Flood , also known as the Grote Manndrenke , hit the entire southern coast of the North Sea. Chronicles of the time again record more than 100,000 deaths, large parts of the coast were lost permanently to the sea, including the now legendary lost city of Rungholt . In the 20th century, the North Sea flood of 1953 flooded several nations' coasts and cost more than 2,000 lives. 315 citizens of Hamburg died in
5760-433: Is some evidence of this, the effects of seabirds are considered smaller than that of marine mammals and predatory fish (like tuna ). Some seabird species have benefited from fisheries, particularly from discarded fish and offal . These discards compose 30% of the food of seabirds in the North Sea , for example, and compose up to 70% of the total food of some seabird populations. This can have other impacts; for example,
5920-536: Is the Norwegian trench , which extends parallel to the Norwegian shoreline from Oslo to an area north of Bergen . It is between 20 and 30 kilometres (12 and 19 mi) wide and has a maximum depth of 725 metres (2,379 ft). The Dogger Bank , a vast moraine , or accumulation of unconsolidated glacial debris, rises to a mere 15 to 30 m (50 to 100 ft) below the surface. This feature has produced
6080-589: Is the skimmer , which has a unique fishing method: flying along the surface with the lower mandible in the water—this shuts automatically when the bill touches something in the water. The skimmer's bill reflects its unusual lifestyle, with the lower mandible uniquely being longer than the upper one. Surface feeders that swim often have unique bills as well, adapted for their specific prey. Prions have special bills with filters called lamellae to filter out plankton from mouthfuls of water, and many albatrosses and petrels have hooked bills to snatch fast-moving prey. On
6240-448: Is the deepest diver of the shearwaters, having been recorded diving below 70 metres (230 ft). Some albatross species are also capable of limited diving, with light-mantled sooty albatrosses holding the record at 12 metres (40 ft). Of all the wing-propelled pursuit divers, the most efficient in the air are the albatrosses, and they are also the poorest divers. This is the dominant guild in polar and subpolar environments, but it
6400-518: The Baltic Sea . The largest and most important rivers flowing into the North Sea are the Elbe and the Rhine – Meuse . Around 185 million people live in the catchment area of the rivers discharging into the North Sea encompassing some highly industrialized areas. For the most part, the sea lies on the European continental shelf with a mean depth of 90 metres (300 ft). The only exception
6560-525: The Battle of Heligoland Bight , the Battle of the Dogger Bank , and the Battle of Jutland . World War I also brought the first extensive use of submarine warfare , and a number of submarine actions occurred in the North Sea. The Second World War also saw action in the North Sea, though it was restricted more to aircraft reconnaissance and action by fighter/bomber aircraft, submarines and smaller vessels such as minesweepers and torpedo boats . After
Brent Spar - Misplaced Pages Continue
6720-638: The British Prime Minister , John Major at a G7 conference in Halifax , Nova Scotia . Support from within the oil industry was not unanimous. Although oil production companies supported Shell's position, influential companies in the offshore construction sector stood to make money from onshore dismantling if a precedent could be set, and consequently supported the Greenpeace point of view. On 20 June, Shell had decided that their position
6880-418: The Cretaceous period , and modern seabird families emerged in the Paleogene . Seabirds generally live longer, breed later and have fewer young than other birds, but they invest a great deal of time in their young. Most species nest in colonies , varying in size from a few dozen birds to millions. Many species are famous for undertaking long annual migrations , crossing the equator or circumnavigating
7040-528: The English Channel was triggered by the earthquake, which in turn caused a tsunami. The tsunami triggered by the 1755 Lisbon earthquake reached Holland, although the waves had lost their destructive power. The largest earthquake ever recorded in the United Kingdom was the 1931 Dogger Bank earthquake , which measured 6.1 on the Richter magnitude scale and caused a small tsunami that flooded parts of
7200-517: The Last Glacial Maximum when the sea began to flood the European continental shelf. In 2006 a bone fragment was found while drilling for oil in the North Sea. Analysis indicated that it was a Plateosaurus from 199 to 216 million years ago. This was the deepest dinosaur fossil ever found and the first find for Norway. Copepods and other zooplankton are plentiful in the North Sea. These tiny organisms are crucial elements of
7360-965: The Latin names Mare Germanicum and Oceanus Germanicus , and these persisted in use until the First World War. Other common names in use for long periods were the Latin terms Mare Frisicum , as well as the English equivalent, "Frisian Sea". The modern names of the sea in the other local languages are: Danish : Vesterhavet , lit. 'West Sea' [ˈvestɐˌhɛˀvð̩] or Nordsøen [ˈnoɐ̯ˌsøˀn̩] , Dutch : Noordzee , Dutch Low Saxon : Noordzee , French : Mer du Nord , West Frisian : Noardsee , German : Nordsee , Low German : Noordsee , North Frisian : Weestsiie , lit. 'West Sea', Swedish : Nordsjön , Bokmål : Nordsjøen [ˈnûːrˌʂøːn] , Nynorsk : Nordsjøen , Scots : North Sea and Scottish Gaelic : An Cuan
7520-595: The Netherlands , Belgium and France . An epeiric sea on the European continental shelf , it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Sea in the north. It is more than 970 kilometres (600 mi) long and 580 kilometres (360 mi) wide, covering 570,000 square kilometres (220,000 sq mi). It hosts key north European shipping lanes and
7680-472: The North Sea flood of 1962 . Though rare, the North Sea has been the site of a number of historically documented tsunamis . The Storegga Slides were a series of underwater landslides, in which a piece of the Norwegian continental shelf slid into the Norwegian Sea. The immense landslips occurred between 8150 BCE and 6000 BCE, and caused a tsunami up to 20 metres (66 ft) high that swept through
7840-715: The Pelagornithidae and the Plotopteridae (a group of large seabirds that looked like the penguins). Modern genera began their wide radiation in the Miocene , although the genus Puffinus (which includes today's Manx shearwater and sooty shearwater ) might date back to the Oligocene . Within the Charadriiformes, the gulls and allies ( Lari ) became seabirds in the late Eocene, and then waders in
8000-1016: The Phare de Walde (Walde Lighthouse, in France, 50°59'37"N, 1°54'53"E) and Leathercoat Point (England, 51°10'01.4"N 1°24'07.8"). northeast of Dover. On the Northwest. From Dunnet Head (58°40'20"N, 3°22'30"W) in Scotland to Tor Ness (58°47'N) in the Island of Hoy , thence through this island to the Kame of Hoy (58°55'N) on to Breck Ness on Mainland (58°58'N) through this island to Costa Head (3°14'W) and Inga Ness (59'17'N) in Westray through Westray, to Bow Head, across to Mull Head (North point of Papa Westray ) and on to Seal Skerry (North point of North Ronaldsay ) and thence to Horse Island (South point of
8160-703: The Polynesians to locate tiny landmasses in the Pacific. Seabirds have provided food for fishermen away from home, as well as bait. Famously, tethered cormorants have been used to catch fish directly. Indirectly, fisheries have also benefited from guano from colonies of seabirds acting as fertilizer for the surrounding seas. Negative effects on fisheries are mostly restricted to raiding by birds on aquaculture , although long-lining fisheries also have to deal with bait stealing. There have been claims of prey depletion by seabirds of fishery stocks, and while there
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#17327753272838320-826: The Shetland Islands). On the North. From the North point (Fethaland Point) of the Mainland of the Shetland Islands, across to Graveland Ness (60°39'N) in the Island of Yell , through Yell to Gloup Ness (1°04'W) and across to Spoo Ness (60°45'N) in Unst island, through Unst to Herma Ness (60°51'N), on to the SW point of the Rumblings and to Muckle Flugga ( 60°51′N 0°53′W / 60.850°N 0.883°W / 60.850; -0.883 ) all these being included in
8480-608: The Skagerrak and Kattegat , narrow straits that separate Denmark from Norway and Sweden respectively. In the north it is bordered by the Shetland Islands , and connects with the Norwegian Sea , which is a marginal sea in the Arctic Ocean . The North Sea is more than 970 kilometres (600 mi) long and 580 kilometres (360 mi) wide, with an area of 750,000 square kilometres (290,000 sq mi) and
8640-648: The Sphenisciformes (penguins) and Procellariiformes ( albatrosses and petrels ), all of the Suliformes ( gannets and cormorants ) except the darters , and some of the Charadriiformes (the gulls , skuas , terns , auks and skimmers ) are classified as seabirds. The phalaropes are usually included as well, since although they are waders ("shorebirds" in North America), two of
8800-401: The fishing industry in that area. The cost of this option was estimated at between £17M and £20M. Shell proposed that deep sea disposal was the best option for Brent Spar, arguing that their decision had been made on sound scientific principles and data. Dismantling the platform on-shore was more complex from an engineering point of view than disposal at sea. Shell also cited the lower risk to
8960-463: The food chain supporting many species of fish. Over 230 species of fish live in the North Sea. Cod , haddock , whiting , saithe , plaice , sole , mackerel , herring , pouting , sprat , and sandeel are all very common and are fished commercially. Due to the various depths of the North Sea trenches and differences in salinity, temperature, and water movement, some fish such as blue-mouth redfish and rabbitfish reside only in small areas of
9120-401: The health and safety of the workforce with deep sea disposal. Environmentally, Shell considered that sinking would have only a localised effect in a remote deep sea region which had little resource value . It was considered that this option would be acceptable to the public, to Her Majesty's Government and to regional authorities. Shell acknowledged that sinking the Brent Spar at sea was also
9280-535: The littoral is low and marshy. The east coast and south-east of the North Sea ( Wadden Sea ) have coastlines that are mainly sandy and straight owing to longshore drift , particularly along Belgium and Denmark. The southern coastal areas were originally flood plains and swampy land. In areas especially vulnerable to storm surges, people settled behind elevated levees and on natural areas of high ground such as spits and geestland . As early as 500 BC, people were constructing artificial dwelling hills higher than
9440-677: The millinery trade reached industrial levels. Muttonbirding (harvesting shearwater chicks) developed as important industries in both New Zealand and Tasmania, and the name of one species, the providence petrel , is derived from its seemingly miraculous arrival on Norfolk Island where it provided a windfall for starving European settlers. In the Falkland Islands , hundreds of thousands of penguins were harvested for their oil each year. Seabird eggs have also long been an important source of food for sailors undertaking long sea voyages, as well as being taken when settlements grow in areas near
9600-419: The razorbill (an Atlantic auk) requires 64% more energy to fly than a petrel of equivalent size. Many shearwaters are intermediate between the two, having longer wings than typical wing-propelled divers but heavier wing loadings than the other surface-feeding procellariids , leaving them capable of diving to considerable depths while still being efficient long-distance travellers. The short-tailed shearwater
9760-481: The shearwaters and gadfly petrels). Surface feeders in flight include some of the most acrobatic of seabirds, which either snatch morsels from the water (as do frigate-birds and some terns), or "walk", pattering and hovering on the water's surface, as some of the storm-petrels do. Many of these do not ever land in the water, and some, such as the frigatebirds, have difficulty getting airborne again should they do so. Another seabird family that does not land while feeding
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#17327753272839920-741: The 13th century the Hanseatic League , though centred on the Baltic Sea , started to control most of the trade through important members and outposts on the North Sea. The League lost its dominance in the 16th century, as neighbouring states took control of former Hanseatic cities and outposts. Their internal conflict prevented effective cooperation and defence. As the League lost control of its maritime cities, new trade routes emerged that provided Europe with Asian, American, and African goods. The 17th century Dutch Golden Age saw Dutch maritime power at its zenith. Important overseas colonies,
10080-526: The Antarctic mainland, are unlikely to find anything to eat around their breeding sites. The marbled murrelet nests inland in old growth forest , seeking huge conifers with large branches to nest on. Other species, such as the California gull , nest and feed inland on lakes, and then move to the coasts in the winter. Some cormorant, pelican , gull and tern species have individuals that never visit
10240-466: The Arctic tern; birds that nest in New Zealand and Chile and spend the northern summer feeding in the North Pacific off Japan, Alaska and California, an annual round trip of 64,000 kilometres (40,000 mi). Other species also migrate shorter distances away from the breeding sites, their distribution at sea determined by the availability of food. If oceanic conditions are unsuitable, seabirds will emigrate to more productive areas, sometimes permanently if
10400-484: The Austral summer in Antarctica. Other species also undertake trans-equatorial trips, both from the north to the south, and from south to north. The population of elegant terns , which nest off Baja California , splits after the breeding season with some birds travelling north to the Central Coast of California and some travelling as far south as Peru and Chile to feed in the Humboldt Current . The sooty shearwater undertakes an annual migration cycle that rivals that of
10560-405: The Brent Spar, and took two of these forward for serious consideration. The first option involved towing the Brent Spar to a shallow water harbour to decontaminate it and reuse the materials used in its construction. Any unusable waste could be disposed of on land. Technically, this option was more complex and presented a greater hazard to the workforce. This option was estimated to cost £41M. There
10720-410: The British coast. Shallow epicontinental seas like the current North Sea have since long existed on the European continental shelf . The rifting that formed the northern part of the Atlantic Ocean during the Jurassic and Cretaceous periods, from about 150 million years ago , caused tectonic uplift in the British Isles. Since then, a shallow sea has almost continuously existed between
10880-524: The Earth in some cases. They feed both at the ocean's surface and below it, and even on each other. Seabirds can be highly pelagic , coastal, or in some cases spend a part of the year away from the sea entirely. Seabirds and humans have a long history together: They have provided food to hunters , guided fishermen to fishing stocks, and led sailors to land. Many species are currently threatened by human activities such as oil spills , nets, climate change and severe weather. Conservation efforts include
11040-532: The Maury Channel, the North Feni Ridge and the Rockall Trough . At these three sites, FRS carried out: The North Feni Ridge was found to include a narrow channel. The Rockall Trough area was found to be a gently sloping basin between the Anton Dohrn Seamount and the Wyville-Thomsom Ridge . The Maury Channel area was found to be a flat, gently sloping area. Infaunal communities were found to be high in diversity and low in abundance , characteristic of unimpacted sediments. These communities were thought to have
11200-407: The Middle Ages and into the modern era. The North Sea was the centre of the Vikings' rise . The Hanseatic League , the Dutch Republic , and the British each sought to gain command of the North Sea and access to the world's markets and resources. As Germany's only outlet to the ocean, the North Sea was strategically important through both world wars. The coast has diverse geology and geography. In
11360-445: The Middle Ages through the 15th century, the northern European coastal ports exported domestic goods, dyes, linen, salt, metal goods and wine. The Scandinavian and Baltic areas shipped grain, fish, naval necessities, and timber. In turn, the North Sea countries imported high-grade cloths, spices, and fruits from the Mediterranean region. Commerce during this era was mainly conducted by maritime trade due to underdeveloped roadways. In
11520-486: The Netherlands. The North Sea Floods of 1953 and 1962 were the impetus for further raising of the dikes as well as the shortening of the coast line so as to present as little surface area as possible to the punishment of the sea and the storms. Currently, 27% of the Netherlands is below sea level protected by dikes, dunes, and beach flats. Coastal management today consists of several levels. The dike slope reduces
11680-559: The North Feni Ridge area may indicate that this area may have been accumulative , but that this would not preclude deep-sea disposal of the platform. Having received these conclusions, Shell opted for the North Feni Ridge site, and applied to the British government for a licence to dispose of the rig at sea. This was approved in December 1994. Greenpeace became aware of the plan to sink the Brent Spar at sea on 16 February 1995. The organization had been campaigning against ocean dumping in
11840-926: The North Sea are home to nature reserves including the Ythan Estuary , Fowlsheugh Nature Preserve, and Farne Islands in the UK and the Wadden Sea National Parks in Denmark, Germany and the Netherlands. These locations provide breeding habitat for dozens of bird species. Tens of millions of birds make use of the North Sea for breeding, feeding, or migratory stopovers every year. Populations of black-legged kittiwakes , Atlantic puffins , northern gannets , northern fulmars , and species of petrels , seaducks , loons (divers), cormorants , gulls , auks , and terns , and many other seabirds make these coasts popular for birdwatching . The North Sea
12000-618: The North Sea area; thence up the meridian of 0°53' West to the parallel of 61°00' North and eastward along this parallel to the coast of Norway, the whole of Viking Bank is thus included in the North Sea. On the East. The Western limit of the Skagerrak [A line joining Hanstholm ( 57°07′N 8°36′E / 57.117°N 8.600°E / 57.117; 8.600 ) and the Naze ( Lindesnes , 58°N 7°E / 58°N 7°E / 58; 7 )]. The average temperature
12160-523: The North Sea during the Migration Period . They made successive invasions of the island from what is now the Netherlands, Denmark, and Germany. The Viking Age began in 793 with the attack on Lindisfarne ; for the next quarter-millennium, the Vikings ruled the North Sea. In their superior longships , they raided, traded, and established colonies and outposts along the coasts of the sea. From
12320-613: The North Sea include species of wrack , among them bladder wrack , knotted wrack , and serrated wrack. Algae , macroalgal, and kelp , such as oarweed and laminaria hyperboria, and species of maerl are found as well. Eelgrass , formerly common in the entirety of the Wadden Sea, was nearly wiped out in the 20th century by a disease. Similarly, sea grass used to coat huge tracts of ocean floor, but have been damaged by trawling and dredging have diminished its habitat and prevented its return. Invasive Japanese seaweed has spread along
12480-426: The North Sea since the early 1980s, monitoring the dumping of radioactive waste and waste from titanium dioxide production and on occasion using high-seas civil disobedience tactics to physically hinder the perpetrators, and lobbying for a comprehensive ban on ocean dumping through the OSPAR convention . Greenpeace objected to the plan to dispose of the Brent Spar at sea on a number of issues: Greenpeace claimed that
12640-500: The North Sea to Great Britain and Scandinavia and reliance by some prehistoric cultures on fishing, whaling, and seaborne trade on the North Sea. The Romans established organised ports in Britain, which increased shipping and began sustained trade the diffusion of cultures and technologies from across or along the North Sea to Great Britain and Scandinavia and reliance by some prehistoric cultures on fishing, whaling, and seaborne trade on
12800-416: The North Sea until the 20th century, when numbers declined due to overfishing . Other factors like the introduction of non-indigenous species , industrial and agricultural pollution , trawling and dredging , human-induced eutrophication , construction on coastal breeding and feeding grounds, sand and gravel extraction, offshore construction , and heavy shipping traffic have also contributed to
12960-590: The North Sea, having the greatest effect on Scotland and the Faeroe Islands . The Dover Straits earthquake of 1580 is among the first recorded earthquakes in the North Sea measuring between 5.6 and 5.9 on the Richter scale. This event caused extensive damage in Calais both through its tremors and possibly triggered a tsunami , though this has never been confirmed. The theory is a vast underwater landslide in
13120-399: The North Sea. Crustaceans are also commonly found throughout the sea. Norway lobster , deep-water prawns , and brown shrimp are all commercially fished, but other species of lobster , shrimp , oyster , mussels and clams all live in the North Sea. Recently non-indigenous species have become established including the Pacific oyster and Atlantic jackknife clam . The coasts of
13280-517: The North Sea. The Romans established organised ports in Britain, which increased shipping and began sustained trade and many Scandinavian tribes participated in raids and wars against the Romans and Roman coinage and manufacturing were important trade goods. When the Romans abandoned Britain in 410, the Germanic Angles , Frisians , Saxons , and Jutes began the next great migration across
13440-500: The North Sea. The wave continues to travel northward in the Atlantic Ocean, and once past the northern tip of Great Britain, the Kelvin wave turns east and south and once again enters the North Sea. The eastern and western coasts of the North Sea are jagged, formed by glaciers during the ice ages . The coastlines along the southernmost part are covered with the remains of deposited glacial sediment. The Norwegian mountains plunge into
13600-502: The Orkney Islands through the mid-16th century, as both Sable Island and Orkney Islands lay within their normal range. Grey whales also resided in the North Sea but were driven to extinction in the Atlantic in the 17th century Other species have dramatically declined in population, though they are still found. North Atlantic right whales , sturgeon , shad , rays , skates , salmon , and other species were common in
13760-463: The Spar contained 5500 tonnes of oil were inaccurate and apologized to Shell on 5 September. This preempted the publication of DNV's report, which endorsed Shell's initial estimates for many pollutants. Greenpeace noted that its opposition to the dumping had never been solely based on the presence or absence of oil, however, and that opposition to the disposal plan was part of a larger campaign opposing
13920-508: The UK was the Scottish Seabird Centre , near the important bird sanctuaries on Bass Rock , Fidra and the surrounding islands. The area is home to huge colonies of gannets, puffins , skuas and other seabirds. The centre allows visitors to watch live video from the islands as well as learn about the threats the birds face and how we can protect them, and has helped to significantly raise the profile of seabird conservation in
14080-540: The UK. Seabird tourism can provide income for coastal communities as well as raise the profile of seabird conservation, although it needs to be managed to ensure it does not harm the colonies and nesting birds. For example, the northern royal albatross colony at Taiaroa Head in New Zealand attracts 40,000 visitors a year. The plight of albatross and large seabirds, as well as other marine creatures, being taken as bycatch by long-line fisheries, has been addressed by
14240-467: The albatrosses and gulls, are more well known to humans. The albatross has been described as "the most legendary of birds", and have a variety of myths and legends associated with them. While it is widely considered unlucky to harm them, the notion that sailors believed that is a myth that derives from Samuel Taylor Coleridge 's famous poem, " The Rime of the Ancient Mariner ", in which a sailor
14400-452: The attention of predators , principally other birds, and many species attend their colonies nocturnally to avoid predation. Birds from different colonies often forage in different areas to avoid competition. Like many birds, seabirds often migrate after the breeding season . Of these, the trip taken by the Arctic tern is the farthest of any bird, crossing the equator in order to spend
14560-454: The bird is young. After fledging, juvenile birds often disperse further than adults, and to different areas, so are commonly sighted far from a species' normal range. Some species, such as the auks, do not have a concerted migration effort, but drift southwards as the winter approaches. Other species, such as some of the storm petrels, diving petrels and cormorants, never disperse at all, staying near their breeding colonies year round. While
14720-548: The cheaper option. Having decided on a preferred method of disposal, Shell contracted Fisheries Research Services (FRS) to investigate possible sites for sinking the facility. There were two stipulations to this search: firstly, that the site was within the UK exclusive economic zone ,and secondly, that the site be deep enough that the sunken buoy would present no hazard to shipping. FRS identified three sites as 12 by 12 mi (20 by 20 km) squares, which were considered suitable;
14880-486: The chicks of the sooty shearwater as they have done for centuries, using traditional stewardship, kaitiakitanga , to manage the harvest, but now also work with the University of Otago in studying the populations. In Greenland , however, uncontrolled hunting is pushing many species into steep decline. Other human factors have led to declines and even extinctions in seabird populations and species. Of these, perhaps
15040-551: The coasts of the Netherlands, Belgium, Germany, and Denmark and low-lying areas of eastern England particularly around The Wash and Fens . Storm surges are caused by changes in barometric pressure combined with strong wind created wave action . The first recorded storm tide flood was the Julianenflut , on 17 February 1164. In its wake, the Jadebusen , (a bay on the coast of Germany), began to form. A storm tide in 1228
15200-429: The contents of the Spar and sent it for testing, to determine the nature of the pollutants which the platform contained. This sample was collected incorrectly, leading to a large overestimate in the contents of the facility. Although Greenpeace quoted Shell's own estimate of the amount of heavy metals and other chemicals on board, they also claimed there were more than 5,500 tonnes of oil on the Spar – while Shell's estimate
15360-535: The decline. For example, a resident orca pod was lost in the 1960s, presumably due to the peak in PCB pollution in this time period. The OSPAR commission manages the OSPAR convention to counteract the harmful effects of human activity on wildlife in the North Sea, preserve endangered species , and provide environmental protection. All North Sea border states are signatories of the MARPOL 73/78 Accords, which preserve
15520-453: The definition of seabirds suggests that the birds in question spend their lives on the ocean, many seabird families have many species that spend some or even most of their lives inland away from the sea. Most strikingly, many species breed tens, hundreds or even thousands of miles inland. Some of these species still return to the ocean to feed; for example, the snow petrel , the nests of which have been found 480 kilometres (300 mi) inland on
15680-451: The disease have scarred digestive tracts from ingesting plastic waste . "When birds ingest small pieces of plastic, they found, it inflames the digestive tract. Over time, the persistent inflammation causes tissues to become scarred and disfigured, affecting digestion, growth and survival." The threats faced by seabirds have not gone unnoticed by scientists or the conservation movement . As early as 1903, U.S. President Theodore Roosevelt
15840-456: The dive to combat natural buoyancy (caused by air trapped in plumage), and thus uses less energy than the dedicated pursuit divers, allowing them to utilise more widely distributed food resources, for example, in impoverished tropical seas. In general, this is the most specialised method of hunting employed by seabirds; other non-specialists (such as gulls and skuas) may employ it but do so with less skill and from lower heights. In brown pelicans,
16000-527: The dumping of all waste into the North Sea. Shell received over 200 individual suggestions for what could be done with the Brent Spar. One of these came from the Stavanger Port Authority. They were planning a quay extension at Mekjarvik , to provide new Roll-On/Roll-Off ferry facilities. It was hoped that using slices of the Spar's hull would save both money and energy that would otherwise have been spent in new steel construction. The Spar
16160-531: The dumping plan. On 23 May, after several attempts, Shell obtained legal permission to evict the Greenpeace protesters from the Brent Spar, and they were eventually taken by helicopter to Aberdeen , Scotland , where they held a press conference. Towing of the platform to its final position began on 11 June. By this time, the call for a boycott of Shell products was being heeded across much of continental northern Europe , damaging Shell's profitability as well as brand image. German Chancellor Helmut Kohl protested to
16320-413: The earliest instances known is in southern Chile, where archaeological excavations in middens has shown hunting of albatrosses, cormorants and shearwaters from 5000 BP. This pressure has led to some species becoming extinct in many places; in particular, at least 20 species of an original 29 no longer breed on Easter Island . In the 19th century, the hunting of seabirds for fat deposits and feathers for
16480-555: The energy of the incoming sea, so that the dike itself does not receive the full impact. Dikes that lie directly on the sea are especially reinforced. The dikes have, over the years, been repeatedly raised, sometimes up to 9 metres (30 ft) and have been made flatter to better reduce wave erosion. Where the dunes are sufficient to protect the land behind them from the sea, these dunes are planted with beach grass ( Ammophila arenaria ) to protect them from erosion by wind, water, and foot traffic. Storm surges threaten, in particular,
16640-470: The establishment of wildlife refuges and adjustments to fishing techniques. There exists no single definition of which groups, families and species are seabirds, and most definitions are in some way arbitrary. Elizabeth Shreiber and Joanna Burger, two seabird scientists, said, "The one common characteristic that all seabirds share is that they feed in saltwater ; but, as seems to be true with any statement in biology, some do not." However, by convention all of
16800-404: The exception of the cormorants and some terns, and in common with most other birds, all seabirds have waterproof plumage . However, compared to land birds, they have far more feathers protecting their bodies. This dense plumage is better able to protect the bird from getting wet, and cold is kept out by a dense layer of down feathers . The cormorants possess a layer of unique feathers that retain
16960-676: The feathers resist abrasion. Seabirds evolved to exploit different food resources in the world's seas and oceans, and to a great extent, their physiology and behaviour have been shaped by their diet . These evolutionary forces have often caused species in different families and even orders to evolve similar strategies and adaptations to the same problems, leading to remarkable convergent evolution , such as that between auks and penguins. There are four basic feeding strategies, or ecological guilds, for feeding at sea: surface feeding, pursuit diving, plunge-diving, and predation of higher vertebrates ; within these guilds, there are multiple variations on
17120-572: The finest fishing location of the North Sea. The Long Forties and the Broad Fourteens are large areas with roughly uniform depth in fathoms (forty fathoms and fourteen fathoms or 73 and 26 m or 240 and 85 ft deep, respectively). These great banks and others make the North Sea particularly hazardous to navigate, which has been alleviated by the implementation of satellite navigation systems . The Devil's Hole lies 320 kilometres (200 mi) east of Dundee , Scotland. The feature
17280-475: The first time in over a hundred years. Seabird mortality caused by long-line fisheries can be greatly reduced by techniques such as setting long-line bait at night, dying the bait blue, setting the bait underwater, increasing the amount of weight on lines and by using bird scarers, and their deployment is increasingly required by many national fishing fleets. One of the Millennium Projects in
17440-478: The frequency of breeding failures due to unfavourable marine conditions, and the relative lack of predation compared to that of land-living birds. Because of the greater investment in raising the young and because foraging for food may occur far from the nest site, in all seabird species except the phalaropes, both parents participate in caring for the young, and pairs are typically at least seasonally monogamous . Many species, such as gulls, auks and penguins, retain
17600-531: The highest variability where there is fresh water inflow, such as at the Rhine and Elbe estuaries, the Baltic Sea exit and along the coast of Norway. The main pattern to the flow of water in the North Sea is an anti-clockwise rotation along the edges. The North Sea is an arm of the Atlantic Ocean receiving the majority of ocean current from the northwest opening, and a lesser portion of warm current from
17760-468: The longest period of parental care of any bird except a few raptors and the southern ground hornbill , with each chick fledging after four to six months and continued assistance after that for up to fourteen months. Due to the extended period of care, breeding occurs every two years rather than annually for some species. This life-history strategy has probably evolved both in response to the challenges of living at sea (collecting widely scattered prey items),
17920-408: The marine ecosystems caused by dredging, which alters the biodiversity of the seafloor, can also have a negative impact. The hunting of seabirds and the collecting of seabird eggs have contributed to the declines of many species, and the extinction of several, including the great auk and the spectacled cormorant . Seabirds have been hunted for food by coastal peoples throughout history—one of
18080-489: The marine environment by preventing pollution from ships. Germany, Denmark, and the Netherlands also have a trilateral agreement for the protection of the Wadden Sea , or mudflats , which run along the coasts of the three countries on the southern edge of the North Sea. The North Sea has had various names throughout history. One of the earliest recorded names was Septentrionalis Oceanus , or "Northern Ocean", which
18240-580: The middle Miocene ( Langhian ). The highest diversity of seabirds apparently existed during the Late Miocene and the Pliocene . At the end of the latter, the oceanic food web had undergone a period of upheaval due to extinction of considerable numbers of marine species; subsequently, the spread of marine mammals seems to have prevented seabirds from reaching their erstwhile diversity. Seabirds have made numerous adaptations to living on and feeding in
18400-490: The most desirable nesting spaces. The tropical Bonin petrel nests during the winter to avoid competition with the more aggressive wedge-tailed shearwater . When the seasons overlap, the wedge-tailed shearwaters will kill young Bonin petrels in order to use their burrows. Many seabirds show remarkable site fidelity , returning to the same burrow, nest or site for many years, and they will defend that site from rivals with great vigour. This increases breeding success, provides
18560-552: The most serious are introduced species . Seabirds, breeding predominantly on small isolated islands, are vulnerable to predators because they have lost many behaviours associated with defence from predators. Feral cats can take seabirds as large as albatrosses, and many introduced rodents, such as the Pacific rat , take eggs hidden in burrows. Introduced goats, cattle, rabbits and other herbivores can create problems, particularly when species need vegetation to protect or shade their young. The disturbance of breeding colonies by humans
18720-679: The north, deep fjords and sheer cliffs mark much of its Norwegian and Scottish coastlines respectively, whereas in the south, the coast consists mainly of sandy beaches, estuaries of long rivers and wide mudflats . Due to the dense population, heavy industrialisation , and intense use of the sea and the area surrounding it, various environmental issues affect the sea's ecosystems. Adverse environmental issues – commonly including overfishing , industrial and agricultural runoff , dredging , and dumping, among others – have led to several efforts to prevent degradation and to safeguard long-term economic benefits. The North Sea
18880-428: The ocean lead to decreased availability of food and colonies are more often flooded as a consequence of sea level rise and extreme rainfall events. Heat stress from extreme temperatures is an additional threat. Some seabirds have used changing wind patterns to forage further and more efficiently. In 2023, plasticosis , a new disease caused solely by plastics, was discovered in seabirds. The birds identified as having
19040-841: The other hand, most gulls are versatile and opportunistic feeders who will eat a wide variety of prey, both at sea and on land. Pursuit diving exerts greater pressures (both evolutionary and physiological) on seabirds, but the reward is a greater area in which to feed than is available to surface feeders. Underwater propulsion is provided by wings (as used by penguins, auks, diving petrels and some other species of petrel) or feet (as used by cormorants, grebes , loons and several types of fish-eating ducks ). Wing-propelled divers are generally faster than foot-propelled divers. The use of wings or feet for diving has limited their utility in other situations: loons and grebes walk with extreme difficulty (if at all), penguins cannot fly, and auks have sacrificed flight efficiency in favour of diving. For example,
19200-418: The platform, and metal that would remain in the structure after decommissioning. Scale is a by-product of oil production and, because of the radioactivity found in the rocks from which the oil is extracted, is considered to be low-level radioactive waste . It is regularly dealt with on-shore by workers wearing breathing masks to prevent inhalation of dust. Shell examined a number of options for disposing of
19360-500: The prevailing flood levels. It was only around the beginning of the High Middle Ages , in 1200 AD, that inhabitants began to connect single ring dikes into a dike line along the entire coast, thereby turning amphibious regions between the land and the sea into permanent solid ground. The modern form of the dikes supplemented by overflow and lateral diversion channels, began to appear in the 17th and 18th centuries, built in
19520-503: The removal of exotic invaders from increasingly large islands. Feral cats have been removed from Ascension Island , Arctic foxes from many islands in the Aleutian Islands , and rats from Campbell Island . The removal of these introduced species has led to increases in numbers of species under pressure and even the return of extirpated ones. After the removal of cats from Ascension Island, seabirds began to nest there again for
19680-465: The same mate for several seasons, and many petrel species mate for life. Albatrosses and procellariids , which mate for life, take many years to form a pair bond before they breed, and the albatrosses have an elaborate breeding dance that is part of pair-bond formation. Ninety-five percent of seabirds are colonial, and seabird colonies are among the largest bird colonies in the world, providing one of Earth's great wildlife spectacles. Colonies of over
19840-453: The scientific arguments for ocean dumping were being used as a way of disguising Shell's primary aim, which was to cut costs. Four Greenpeace activists first occupied Brent Spar on 30 April 1995. In total, 25 activists, photographers and journalists were involved in this stage of occupation. They decided to cover up the Exxon logos on the platform. At this time, activists collected a sample of
20000-403: The scientific journal Nature for their lack of interest in facts. Greenpeace moved to distance itself from its "5500 tonnes" claim, after the Brent Spar argument was won. 61°03′N 1°40′E / 61.050°N 1.667°E / 61.050; 1.667 North Sea Download coordinates as: The North Sea lies between Great Britain , Denmark , Norway , Germany ,
20160-653: The sea at all, spending their lives on lakes, rivers, swamps and, in the case of some of the gulls, cities and agricultural land. In these cases, it is thought that these terrestrial or freshwater birds evolved from marine ancestors. Some seabirds, principally those that nest in tundra , as skuas and phalaropes do, will migrate over land as well. The more marine species, such as petrels, auks and gannets , are more restricted in their habits, but are occasionally seen inland as vagrants. This most commonly happens to young inexperienced birds, but can happen in great numbers to exhausted adults after large storms , an event known as
20320-469: The sea creating deep fjords and archipelagos . South of Stavanger, the coast softens, the islands become fewer. The eastern Scottish coast is similar, though less severe than Norway. From north east of England , the cliffs become lower and are composed of less resistant moraine , which erodes more easily, so that the coasts have more rounded contours. In the Netherlands, Belgium and in East Anglia
20480-507: The sea's edge (coast), but are also not treated as seabirds. Sea eagles and other fish-eating birds of prey are also typically excluded, however tied to marine environments they may be. German ornithologist Gerald Mayr defined the "core waterbird" clade Aequornithes in 2010. This lineage gives rise to the Gaviiformes , Sphenisciformes , Procellariiformes, Ciconiiformes , Suliformes and Pelecaniformes . The tropicbirds are part of
20640-407: The sea. Wing morphology has been shaped by the niche an individual species or family has evolved , so that looking at a wing's shape and loading can tell a scientist about its life feeding behaviour. Longer wings and low wing loading are typical of more pelagic species, while diving species have shorter wings. Species such as the wandering albatross , which forage over huge areas of sea, have
20800-402: The seabed and release its contents over a restricted area. Due to the uncertainty associated with detonating explosives, a number of possible scenarios were envisaged. First, the structure would fall to the seabed in one piece, releasing its contaminants slowly, and affecting the seabed for around 1,600 ft (500 m) "down-current". Second, the structure might disintegrate as it fell through
20960-413: The shores of the sea clogging harbours and inlets and has become a nuisance. Due to the heavy human populations and high level of industrialization along its shores, the wildlife of the North Sea has suffered from pollution, overhunting, and overfishing. Flamingos and pelicans were once found along the southern shores of the North Sea, but became extinct over the second millennium. Walruses frequented
21120-416: The skewed sex ratio of western gulls in southern California. Oil spills are also a threat to seabirds: the oil is toxic, and bird feathers become saturated by the oil, causing them to lose their waterproofing. Oil pollution in particular threatens species with restricted ranges or already depressed populations. Climate change mainly affect seabirds via changes to their habitat : various processes in
21280-432: The skills of plunge-diving take several years to fully develop—once mature, they can dive from 20 m (66 ft) above the water's surface, shifting the body before impact to avoid injury. It may be that plunge divers are restricted in their hunting grounds to clear waters that afford a view of their prey from the air. While they are the dominant guild in the tropics, the link between plunge diving and water clarity
21440-471: The smaller opening at the English Channel. These tidal currents leave along the Norwegian coast. Surface and deep water currents may move in different directions. Low salinity surface coastal waters move offshore, and deeper, denser high salinity waters move inshore. The North Sea located on the continental shelf has different waves from those in deep ocean water. The wave speeds are diminished and
21600-496: The spread of the northern fulmar through the United Kingdom is attributed in part to the availability of discards. Discards generally benefit surface feeders, such as gannets and petrels, to the detriment of pursuit divers like penguins and guillemots, which can get entangled in the nets. Fisheries also have negative effects on seabirds, and these effects, particularly on the long-lived and slow-breeding albatrosses, are
21760-695: The squid eaten are too large to have been caught alive, and include mid-water species likely to be beyond the reach of albatrosses. Some species will also feed on other seabirds; for example, gulls, skuas and pelicans will often take eggs, chicks and even small adult seabirds from nesting colonies, while the giant petrels can kill prey up to the size of small penguins and seal pups. Seabirds' life histories are dramatically different from those of land birds. In general, they are K-selected , live much longer (anywhere between twenty and sixty years), delay breeding for longer (for up to ten years), and invest more effort into fewer young. Most species will only have one clutch
21920-430: The structure. Brent Spar was 482 ft (147 m) high and 95 ft (29 m) in diameter, and displaced 66,000 tonnes. The draft of the platform was such that manoeuvring in the North Sea south of Orkney was not possible. The storage tank section had a capacity of 300,000 barrels of crude oil . This section was built from 0.79 in (20 mm) thick steel plate, reinforced by ribs and cross-braces. It
22080-495: The theme. Many seabirds feed on the ocean's surface, as the action of marine currents often concentrates food such as krill , forage fish , squid , or other prey items within reach of a dipped head. Surface feeding itself can be broken up into two different approaches, surface feeding while flying (for example as practiced by gadfly petrels , frigatebirds , and storm petrels ), and surface feeding while swimming (examples of which are practiced by gulls , fulmars , many of
22240-491: The three species ( Red and Red-necked ) are oceanic for nine months of the year, crossing the equator to feed pelagically. Loons and grebes , which nest on lakes but winter at sea, are usually categorized as water birds, not seabirds. Although there are a number of sea ducks in the family Anatidae that are truly marine in the winter, by convention they are usually excluded from the seabird grouping. Many waders (or shorebirds) and herons are also highly marine, living on
22400-499: The tropicbirds and some penguins), but most of the colour in seabirds appears in the bills and legs. The plumage of seabirds is thought in many cases to be for camouflage , both defensive (the colour of US Navy battleships is the same as that of Antarctic prions , and in both cases it reduces visibility at sea) and aggressive (the white underside possessed by many seabirds helps hide them from prey below). The usually black wing tips help prevent wear, as they contain melanins that help
22560-888: The uplands of the Fennoscandian Shield and the British Isles. This precursor of the current North Sea has grown and shrunk with the rise and fall of the eustatic sea level during geologic time. Sometimes it was connected with other shallow seas, such as the sea above the Paris Basin to the south-west, the Paratethys Sea to the south-east, or the Tethys Ocean to the south. During the Late Cretaceous, about 85 million years ago , all of modern mainland Europe except for Scandinavia
22720-568: The war on the side of Japan. During the First World War , Great Britain's Grand Fleet and Germany's Kaiserliche Marine faced each other in the North Sea, which became the main theatre of the war for surface action. Britain's larger fleet and North Sea Mine Barrage were able to establish an effective blockade for most of the war, which restricted the Central Powers ' access to many crucial resources. Major battles included
22880-488: The war, hundreds of thousands of tons of chemical weapons were disposed of by being dumped in the North Sea. Sea bird Seabirds (also known as marine birds ) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution , as the same environmental problems and feeding niches have resulted in similar adaptations. The first seabirds evolved in
23040-401: The water column. This would release contaminants in a single burst, and have an effect for 3,300 ft (1,000 m) "down current" of the final resting place, although this would last for a shorter time than in the first instance. Third, the structure could fail catastrophically when the explosives detonated, releasing its contaminants into the surface waters. This would affect sea birds and
23200-406: The wave amplitudes are increased. In the North Sea there are two amphidromic systems and a third incomplete amphidromic system. In the North Sea the average tide difference in wave amplitude is between zero and eight metres (26 ft). The Kelvin tide of the Atlantic Ocean is a semidiurnal wave that travels northward. Some of the energy from this wave travels through the English Channel into
23360-587: The west coast of Scotland, at a depth of around 1.6 mi (2.5 km)). Greenpeace organized a worldwide, high-profile media campaign against this plan occupying Brent Spar for more than three weeks. In the face of public and political opposition in northern Europe (including a widespread boycott of Shell service stations, some physical attacks and an arson attack on a service station in Germany ), Shell abandoned its plans to dispose of Brent Spar at sea — whilst continuing to stand by its claim that this
23520-584: Was 22 metres (72 ft); another study, this time on Cory's shearwaters nesting near Corsica , found that of nine out of 61 male chicks that returned to breed at their natal colony bred in the burrow they were raised in, and two actually bred with their own mother. Colonies are usually situated on islands, cliffs or headlands, which land mammals have difficulty accessing. This is thought to provide protection to seabirds, which are often very clumsy on land. Coloniality often arises in types of bird that do not defend feeding territories (such as swifts , which have
23680-549: Was 50 tonnes. For context, the Exxon Valdez oil spill involved around 42,000 tonnes. Greenpeace mounted an energetic media campaign that influenced public opinion against Shell's preferred option. It disputed Shell's estimates of the contaminants on the Brent Spar, saying that these were much more than initially estimated. On 9 May, the German government issued a formal objection to the British government, with respect to
23840-595: Was a scattering of islands. By the Early Oligocene , 34 to 28 million years ago , the emergence of Western and Central Europe had almost completely separated the North Sea from the Tethys Ocean, which gradually shrank to become the Mediterranean as Southern Europe and South West Asia became dry land. The North Sea was cut off from the English Channel by a narrow land bridge until that
24000-566: Was breached by at least two catastrophic floods between 450,000 and 180,000 years ago. Since the start of the Quaternary period about 2.6 million years ago , the eustatic sea level has fallen during each glacial period and then risen again. Every time the ice sheet reached its greatest extent, the North Sea became almost completely dry, the dry landmass being known as Doggerland , whose northern regions were themselves known to have been glaciated. The present-day coastline formed after
24160-632: Was cited by Pliny . He also noted that the Cimbri called it Morimarusa – "Dead Sea". The name "North Sea" probably came into English, however, via the Dutch Noordzee , who named it thus either in contrast with the Zuiderzee ("South Sea"), located south of Frisia , or because the sea is generally to the north of the Netherlands. Before the adoption of "North Sea", the names used in English were "German Sea" or "German Ocean", referred to as
24320-423: Was completed by placing a concrete slab across the rings. The Spar's living quarters and operations module were removed and scrapped onshore at a Norwegian landfill site. While the Brent Spar was being dismantled, quantities of the endangered cold-water coral Lophelia pertusa were found growing on the legs of the platform. At the time, this was considered unusual, although recent studies have shown this to be
24480-679: Was convinced of the need to declare Pelican Island in Florida a National Wildlife Refuge to protect the bird colonies (including the nesting brown pelicans ), and in 1909 he protected the Farallon Islands. Today many important seabird colonies are given some measure of protection, from Heron Island in Australia to Triangle Island in British Columbia. Island restoration techniques, pioneered by New Zealand, enable
24640-533: Was given temporary moorings in a Norwegian fjord . In January 1998, Shell announced its decision to re-use much of the main structure in the construction of new harbour facilities near Stavanger , Norway . Brent "E" was a floating oil storage facility constructed in 1976 and moored approximately 1.2 mi (2 km) from the Brent "A" oil rig . It was jointly owned by Shell and Esso , and operated wholly by Shell, which gave them responsibility for decommissioning
24800-417: Was known that this section had been stressed and damaged on installation. This led to doubts on whether the facility would retain its structural integrity if it was re-floated into a horizontal position. Shell based its decommissioning decisions on estimates of the quantities of various pollutants, including PCBs , crude oil, heavy metals, and scale, which it had calculated based on the operating activities of
24960-563: Was no longer tenable, and withdrew their plan to sink the Brent Spar. They released the following statement: "Shell's position as a major European enterprise has become untenable. The Spar had gained a symbolic significance out of all proportion to its environmental effect. In consequence, Shell companies were faced with increasingly intense public criticism, mostly in Continental northern Europe. Many politicians and ministers were openly hostile and several called for consumer boycotts. There
25120-413: Was raised vertically in the water by building a lifting cradle, placed underneath the Spar and connected by cables to jacks on board heavy barges . Jacking the cables upwards raised the Spar so that its hull could be cut into 'rings' and slid onto a barge. After cleaning, the rings were placed in the sea beside the existing quay at Mekjarvik and filled with ballast. The construction of the quay extension
25280-469: Was some concern that the facility would disintegrate in shallow coastal water, having a much more economically and environmentally significant effect. The second option involved towing the decommissioned platform into deep water in the North Atlantic , positioning explosives around the waterline, then detonating them, in order to breach the hull and sink the platform. The facility would then fall to
25440-419: Was the safest option, both from an environmental and an industrial health and safety perspective. Greenpeace's own reputation also suffered during the campaign, when it had to acknowledge that its assessment of the oil remaining in Brent Spar's storage tanks had been grossly overestimated. Following Shell's decision to pursue only on-shore disposal options, as favoured by Greenpeace and its supporters, Brent Spar
25600-638: Was violence against Shell service stations, accompanied by threats to Shell staff. " In early July, the Norwegian government gave Shell permission to mothball the Brent Spar in Erfjord . It remained there for several years while other options for disposal were considered. Having moored the Brent Spar in Erfjord, Shell commissioned the independent Norwegian consultancy Det Norske Veritas (DNV) to conduct an audit of Spar's contents and investigate Greenpeace's allegations. Greenpeace admitted that its claims that
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