North Sea

Coordinates	28°36′36″N77°13′48″N
Ocean name	North Sea
Image ocean	NASA NorthSea1 2.jpg
Location	Atlantic Ocean
Coords
Inflow	Forth, Ythan, Elbe, Weser, Ems, Rhine/Waal, Meuse, Scheldt, Spey, Tay, Thames, Humber, Tees, Tyne, Wear, Crouch
Basin countries	Norway, Denmark, Germany, Netherlands, Belgium, France and the United Kingdom (England, Scotland)
Length km	960
Width km	580
Area km2	750000
Depth m	95
Max-depth m	700
Volume km3	94000
Temperature high c	17
Temperature low c	6
Salinity	3.4 to 3.5%
Reference	Safety at Sea and Royal Belgian Institute of Natural Sciences

The North Sea is a marginal sea of the Atlantic Ocean located between Great Britain and Scandinavia. An epeiric (or "shelf") sea on the European continental shelf, it connects to the ocean through the English Channel in the south and the Norwegian Sea in the north. It is more than long and wide, with an area of around .

The North Sea has long been the site of important European shipping lanes as well as a major fishery. The sea is a popular destination for recreation and tourism in bordering countries and more recently has developed into a rich source of energy resources including fossil fuels, wind, and early efforts in wave power.

Historically, the North Sea has featured prominently in geopolitical and military affairs, particularly in Northern Europe but also globally through the power northern European actors projected worldwide during much of the Middle Ages and modern era. The North Sea was center of the Vikings' rise and subsequently, the Hanseatic League, the Netherlands, and the British each sought to dominate the North Sea and through it to control access the markets and resources of the world. As Germany's only outlet to the ocean, the North Sea continued to be strategically important through both World Wars.

The coast of the North Sea presents a diversity of geological and geographical features. In the north, deep fjords and sheer cliffs mark the Norwegian and Scottish coastlines, whereas the south consist primarily of sandy beaches and wide mudflats. Due to the dense population, heavy industrialization, and intense use of the sea and area surrounding it, there have been a number of environmental issues affecting the sea's ecosystems. Environmental concerns—commonly including overfishing, industrial and agricultural runoff, dredging, and dumping among others—have led to a number of efforts to prevent degradation of the sea while still making use of its economic potential.

Geography

The North Sea is bounded by the Orkney Islands and east coasts of England and Scotland 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.

It is more than long and wide, with an area of and a volume of . Around the edges of the North Sea are sizeable islands and archipelagos, including Shetland, Orkney, and the Frisian Islands. Around 184 million people live in the catchment area of the rivers that flow into the North Sea encompassing some highly industrialized areas.

Major features

For the most part, the sea lies on the European continental shelf with a mean depth of . The only exception is the Norwegian trench, which extends parallel to the Norwegian shoreline from Oslo to an area north of Bergen. This feature has produced the finest fishing location of the North Sea. which has been alleviated by the implementation of satellite navigation systems. The Devil's Hole lies east of Dundee, Scotland. The feature is a series of asymmetrical trenches between long, wide and up to deep.

Extent

The International Hydrographic Organization defines the limits of the North Sea as follows:

On the Southwest. A line joining the Walde Lighthouse (France, 1°55'E) and Leathercoat Point (England, 51°10'N).

On the Northwest. From Dunnet Head (3°22'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 to 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 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 () all these being included in 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 being thus included in the North Sea.

On the East. The Western limit of the Skagerrak [A line joining Hanstholm () and the Naze (Lindesnes, )].

Hydrology

Temperature and salinity

The average temperature in summer is and in the winter. Air temperatures in January range on average between and in July between . The winter months see frequent gales and storms.

Water circulation and tides

s mainly entering via the north entrance exiting along Norwegian coast]]

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 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 in shore.

The North Sea located on the continental shelf has different waves than those in deep ocean water. The wave speeds are diminished and 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 .

Coasts

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. In Holland, Belgium and in the east of England (East Anglia) the littoral is low and marshy.

Coastal management

(Closure-dike) is a major dam in the Netherlands]]

The southern coastal areas were originally amphibious flood plains and swampy land. In areas especially vulnerable to storm tides, people settled behind elevated levees and on natural areas of high ground such as spits and Geestland. 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 the Netherlands. The North Sea Floods of 1953 and 1962 were 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 the energy of the incoming sea, so that the dike itself does not receive the full impact. Where the dunes are sufficient to protect the land behind them from the sea, these dunes are planted with beach grass to protect them from erosion by wind, water, and foot traffic.

Storm tides

, North Sea flood of 1953.]] Storm tides threaten, in particular, the coasts of the Netherlands, Belgium, Germany, and Denmark and low lying areas of eastern England particularly around The Wash and Fens.

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 is recorded to have killed more than 100,000 people. In 1362, the Second Marcellus Flood, also known as the Grote Manndränke, hit the entire southern coast of the North Sea. Chronicles of the time again record more than 100,000 deaths as 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 the North Sea flood of 1962.

Tsunamis

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 BC and 6000 BC, and caused a tsunami up to high that swept through 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 the English Channel was triggered by the earthquake, which in turn caused a tsunami.

Geology

and , as Central Europe became dry land |image=Mediterranean Rupelian.jpg | width=180 | height=144 | image-width=360 |annotations= }} 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 , caused tectonic uplift in the British Isles. Since then, a shallow sea has almost continuously existed between the highs 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. (c. 8,000BC), which provided a land bridge between Great Britain and continental Europe]] During the Late Cretaceous, about , all of modern mainland Europe except for Scandinavia was a scattering of islands. The North Sea was cut off from the English Channel by a narrow land bridge until that was breached by at least two catastrophic floods between 450,000 and 180,000 years ago. Since the start of the Quaternary period about , 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 present-day coastline formed after 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.

Natural history

Fish and shellfish

s, blue mussels and cockles in the Wadden Sea in the Netherlands.]] Copepods and other zooplankton are plentiful in the North Sea. These tiny organisms are crucial elements of the food chain supporting many species of fish. 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 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. 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 fulmars, and species of petrels, gannets, seaducks, loons (divers), cormorants, gulls, auks, and terns, and many other seabirds make these coasts popular for birdwatching. North Sea cetaceans include various porpoise, dolphin and whale species.

Flora

bloom in the North Sea.]] Plant species in 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. 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 the shores of the sea clogging harbours and inlets and has become a nuisance.

Biodiversity and conservation

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, pelicans, and Great Auk were once found along the southern shores of the North Sea, but went extinct over the 2nd millennium. Gray whale 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. Right whales, sturgeon, shad, rays, skates, salmon, and other species were common in 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 the decline. All North Sea border states are signatories of the MARPOL 73/78 Accords, which preserve 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.

History

Name

showing the "Oceanus Germanicus"]] Through history various names have been used for the North Sea. One of the earliest recorded names was Septentrionalis Oceanus, or "Northern Ocean," which was cited by Pliny. 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 simply because the sea is generally to the north of the Netherlands. Prior to the adoption of "North Sea," "German Sea" or "German Ocean"--from the Latin name "Mare Germanicum" and "Oceanus Germanicus"--were the names in English, and they persisted even into the late 19th Century.

Early history

The North Sea has provided waterway access for commerce and conquest. Many areas have access to the North Sea with its long coastline and European rivers that empty into it. When the Romans abandoned Britain in 410 the Germanic Angles, Saxons, and Jutes began the next great migration across the North Sea during the Migration Period invading England.

The Viking Age began in 793 with the attack on Lindisfarne and for the next quarter-millennium the Vikings ruled the North Sea. In their superior longships, they raided, traded, and established colonies and outposts on the Sea's coasts. From 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

In 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 and internal conflict prevented effective cooperation and defence. Furthermore, as the League lost control of its maritime cities, new trade routes emerged that provided Europe with Asian, American, and African goods.

Age of sail

of 1666 by Willem van de Velde the Younger.]] The 17th century Dutch Golden Age during which Dutch herring, cod and whale fisheries reached an all time high Important overseas colonies, a vast merchant marine, powerful navy and large profits made the Dutch the main challengers to an ambitious England. This rivalry led to the first three Anglo-Dutch Wars between 1652 and 1673, which ended with Dutch victories. The Great Northern War (1700–21) and the War of the Spanish Succession (1701–1714) were fought concurrently. The British did not face a challenge to their dominance of the North Sea until the 20th century.

Modern era

sinks in the Battle of Dogger Bank on 25 January 1915.]] Tensions in the North Sea were again heightened in 1904 by the Dogger Bank incident, in which Russian naval vessels mistook British fishing boats for Japanese ships and fired on them, and then upon each other.

During the First World War, Great Britain's Grand Fleet and Germany's Kaiserliche Marine faced each other on the North Sea, which became the main theatre of the war for surface action. Major battles included the Battle of Heligoland Bight, the Battle of the Dogger Bank, 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 reconnaissances, aircraft fighter/bombers, submarines and smaller vessels such as minesweepers, and torpedo boats and similar vessels.

In the last years of the war and the first years thereafter, hundreds of thousands of tons of weapons were disposed of by being sunk in the North Sea.

After the war, the North Sea lost much of its military significance because it is bordered only by NATO member-states. However, it gained significant economic importance in the 1960s as the states on the North Sea began full-scale exploitation of its oil and gas resources. The North Sea continues to be an active trade route.

Economy

s in the North Sea]]

Political status

Countries that border the North Sea all claim the of territorial waters, within which they have exclusive fishing rights. The Common Fisheries Policy of the European Union (EU) exists to coordinate fishing rights and assist with disputes between EU states and the EU border state of Norway.

After the discovery of mineral resources in the North Sea, the Convention on the Continental Shelf established country rights largely divided along the median line. The median line is defined as the line "every point of which is equidistant from the nearest points of the baselines from which the breadth of the territorial sea of each State is measured." The ocean floor border between Germany, the Netherlands, and Denmark was only reapportioned after protracted negotiations and a judgement of the International Court of Justice.

Oil and gas

As early as 1859, oil was discovered in onshore areas around the North Sea and natural gas as early as 1910.

Test drilling began in 1966 and then, in 1969, Phillips Petroleum Company discovered the Ekofisk oil field distinguished by valuable, low-sulphur oil. Commercial exploitation began in 1971 with tankers and, after 1975, by a pipeline, first to Teesside, England and then, after 1977, also to Emden, Germany.

The exploitation of the North Sea oil reserves began just before the 1973 oil crisis, and the climb of international oil prices made the large investments needed for extraction much more attractive.

Although the production costs are relatively high, the quality of the oil, the political stability of the region, and the nearness of important markets in western Europe has made the North Sea an important oil producing region.

Besides the Ekofisk oil field, the Statfjord oil field is also notable as it was the cause of the first pipeline to span the Norwegian trench. The largest natural gas field in the North Sea, Troll gas field, lies in the Norwegian trench dropping over requiring the construction of the enormous Troll A platform to access it.

The price of Brent Crude, one of the first types of oil extracted from the North Sea, is used today as a standard price for comparison for crude oil from the rest of the world. The North Sea contains western Europe's largest oil and natural gas reserves and is one of the world's key non-OPEC producing regions.

Fishing

The North Sea is Europe's main fishery accounting for over five percent of international commercial fish caught. In 1995, the total volume of fish and shellfish caught in the North Sea was approximately 3.5 million tonnes. Besides fish, it is estimated that one million tonnes of unmarketable by-catch is caught and discarded each year.

In recent decades, overfishing has left many fisheries unproductive, disturbing marine food chain dynamics and costing jobs in the fishing industry. Herring, cod and plaice fisheries may soon face the same plight as mackerel fishing, which ceased in the 1970s due to overfishing. The objective of the European Union Common Fisheries Policy is to minimize the environmental impact associated with resource use by reducing fish discards, increasing productivity of fisheries, stabilising markets of fisheries and fish processing, and supplying fish at reasonable prices for the consumer.

Mineral resources

stones, in varying hues]] In addition to oil, gas, and fish, the states along the North Sea also take millions of cubic metres per year of sand and gravel from the ocean floor. These are used for beach nourishment, land reclamation and construction. Rolled pieces of amber, usually small but occasionally of very large size, may be picked up on the east coast of England. It is also found at various localities along the amber belt of the Danish, Swedish and Frisian Island shorelines.

Renewable energy

Due to the strong prevailing winds, countries on the North Sea, particularly Germany and Denmark, have used the shore for wind power since the 1990s. The North Sea is the home of one of the first large-scale offshore wind farms in the world, Horns Rev 1, completed in 2002. Since then many other wind farms have been commissioned in the North Sea (and elsewhere), including the two largest windfarms in the world as of September 2010; Thanet in the UK and Horns Rev 2 in Denmark.

The expansion of offshore wind farms has met with some resistance. Concerns have include shipping collisions and environmental effects on ocean ecology and wildlife such as fish and migratory birds, however, these concerns were found to be negligible in a long-term study in Denmark released in 2006 and again in a UK government study in 2009. There are also concerns about reliability, and the rising costs of constructing and maintaining offshore wind farms. Despite these, development of North Sea wind power is continuing, with plans for additional wind farms off the coasts of Germany, the Netherlands, and the UK. There have also been proposals for a transnational power grid in the North Sea to connect new offshore wind farms.

Energy production from tidal power is still in a pre-commercial stage. The European Marine Energy Centre has installed a wave testing system at Billia Croo on the Orkney mainland and a tidal power testing station on the nearby island of Eday. Since 2003, a prototype Wave Dragon energy converter has been in operation at Nissum Bredning fjord of northern Denmark.

Tourism

, Netherlands in c. 1900]] The beaches and coastal waters of the North Sea are popular destinations for tourists. The Belgian, Dutch, German and Danish coasts are especially developed for tourism. The North Sea Trail is a long-distance trail linking seven countries around the North Sea. Windsurfing and sailing are popular sports because of the strong winds. Mudflat hiking, recreational fishing and birdwatching

Marine traffic

The North Sea is important for marine transportation and its shipping lanes are among the busiest in the world. as well as the Port of Bruges-Zeebrugge, Europe's leading RoRo port.

, Netherlands]]

Fishing boats, service boats for offshore industries, sport and pleasure craft, and merchant ships to and from North Sea ports and Baltic ports must share routes on the North Sea. The Dover Strait alone sees more than 400 commercial vessels a day. Because of this volume, navigation in the North Sea can be difficult in high traffic zones, so ports have established elaborate vessel traffic services to monitor and direct ships into and out of port.

The North Sea coasts are home to numerous canals and canal systems to facilitate traffic between and among rivers, artificial harbours, and the sea. The Kiel Canal, connecting the North Sea with the Baltic Sea, is the most heavily used artificial seaway in the world reporting an average of 89 ships per day not including sporting boats and other small watercraft in 2009. It saves an average of , instead of the voyage around the Jutland Peninsula. The North Sea Canal connects Amsterdam with the North Sea.

See also

List of the largest islands in the North Sea

Doggerland

List of languages of the North Sea

North Sea Commission

Notes

References

Further reading

External links

The North Sea in brief

See Interactive Map over Oil and Gas Resources in the North Sea

Etymology and History of Names

Old map: Manuscript chart of the North Sea, VOC, ca.1690 (high resolution zoomable scan)

Atlas of Palaeogeography and Lithofacies - Hydrodynamic Environment page 150

Sea temperature and salinity trends

Silver Pit chart

OSPAR Commission Homepage an international commission designed to protect and conserve the North-East Atlantic and its resources

The Physical Geography of Western Europe By Eduard A. Koster

North Sea Region Programme 2007-2013 transnational cooperation programme under the European Regional Development Fund

North Sea Microorganisms: 60+ images of Foraminifera

Category:European seas