Labrador Sea

Labrador Sea

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Encyclopedia
The Labrador Sea is an arm of the North Atlantic Ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...

 between the Labrador Peninsula
Labrador Peninsula
The Labrador Peninsula is a large peninsula in eastern Canada. It is bounded by the Hudson Bay to the west, the Hudson Strait to the north, the Labrador Sea to the east, and the Gulf of Saint Lawrence to the south-east...

 and Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

. The sea is flanked by continental shelves
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...

 to the southwest, northwest, and northeast. It connects to the north with Baffin Bay
Baffin Bay
Baffin Bay , located between Baffin Island and the southwest coast of Greenland, is a marginal sea of the North Atlantic Ocean. It is connected to the Atlantic via Davis Strait and the Labrador Sea...

 through the Davis Strait
Davis Strait
Davis Strait is a northern arm of the Labrador Sea. It lies between mid-western Greenland and Nunavut, Canada's Baffin Island. The strait was named for the English explorer John Davis , who explored the area while seeking a Northwest Passage....

. It has been described as a marginal sea
Marginal sea
The term marginal sea has differing meanings. In one sense the term is equivalent to territorial waters. In another sense the term indicates a partially enclosed sea adjacent to or widely open to the open ocean, but bounded by submarine ridges...

 of the Atlantic.

The sea formed upon separation of the North American Plate
North American Plate
The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...

 and Greenland Plate
Greenland Plate
The Greenland Plate is a supposed tectonic plate bounded to the west by Nares Strait, a probable transform fault, on the southwest by the Ungava transform underlying Davis Strait, on the southeast by the Mid-Atlantic Ridge, and the northeast by the Gakkel Ridge, with its northwest border is still...

 that started about 60 million years ago and stopped about 40 million years ago. It contains one of the world's largest turbidity current
Turbidity current
A turbidity current is a current of rapidly moving, sediment-laden water moving down a slope through water, or another fluid. The current moves because it has a higher density and turbidity than the fluid through which it flows...

 channel systems, the Northwest Atlantic Mid-Ocean Channel
Northwest Atlantic Mid-Ocean Channel
The Northwest Atlantic Mid-Ocean Channel is the main body of a turbidity current system of channels and canyons running on the sea bottom from the Hudson Strait, through the Labrador Sea and ending at the Sohm Abyssal Plain in the Atlantic Ocean. Contrary to most other such systems which fan away...

 (NAMOC), that runs for thousands of kilometers along the sea bottom toward the Atlantic Ocean.

The Labrador Sea is a major source of the North Atlantic Deep Water
North Atlantic Deep Water
North Atlantic Deep Water is a water mass that forms in the North Atlantic Ocean. It is largely formed in the Labrador Sea and in the Greenland Sea by the sinking of highly saline, dense overflow water from the Greenland Sea...

, a cold water mass that flows at great depth along the western edge of the North Atlantic, spreading out to form the largest identifiable water mass in the World Ocean
World Ocean
The World Ocean, world ocean, or global ocean, is the interconnected system of the Earth's oceanic waters, and comprises the bulk of the hydrosphere, covering almost 71% of the Earth's surface, with a total volume of 1.332 billion cubic kilometres.The unity and continuity of the World Ocean, with...

.


History


The Labrador Sea formed upon separation of the North American Plate
North American Plate
The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...

 and Greenland Plate
Greenland Plate
The Greenland Plate is a supposed tectonic plate bounded to the west by Nares Strait, a probable transform fault, on the southwest by the Ungava transform underlying Davis Strait, on the southeast by the Mid-Atlantic Ridge, and the northeast by the Gakkel Ridge, with its northwest border is still...

 that started about 60 million years ago (Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

) and stopped about 40 million years ago. A sedimentary basin
Sedimentary basin
The term sedimentary basin is used to refer to any geographical feature exhibiting subsidence and consequent infilling by sedimentation. As the sediments are buried, they are subjected to increasing pressure and begin the process of lithification...

, which is now buried under the continental shelves, formed during the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

. Onset of magmatic sea-floor spreading was accompanied by volcanic eruptions of picrites and basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

s in the Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

 at the Davis Strait and Baffin Bay.

Between about 500 BC and 1300 AD, the southern coast of the sea contained Dorset
Dorset culture
The Dorset culture was a Paleo-Eskimo culture that preceded the Inuit culture in Arctic North America. It has been defined as having four phases, with distinct technology related to the people's hunting and tool making...

, Beothuk
Beothuk
The Beothuk were one of the aboriginal peoples in Canada. They lived on the island of Newfoundland at the time of European contact in the 15th and 16th centuries...

 and Inuit
Inuit
The Inuit are a group of culturally similar indigenous peoples inhabiting the Arctic regions of Canada , Denmark , Russia and the United States . Inuit means “the people” in the Inuktitut language...

 settlements; Dorset tribes were later replaced by Thule
Thule people
The Thule or proto-Inuit were the ancestors of all modern Inuit. They developed in coastal Alaska by AD 1000 and expanded eastwards across Canada, reaching Greenland by the 13th century. In the process, they replaced people of the earlier Dorset culture that had previously inhabited the region...

 people.

Extent



The International Hydrographic Organization
International Hydrographic Organization
The International Hydrographic Organization is the inter-governmental organisation representing the hydrographic community. It enjoys observer status at the UN and is the recognised competent authority on hydrographic surveying and nautical charting...

 defines the limits of the Labrador Sea as follows:

On the North: the South limit of Davis Strait
Davis Strait
Davis Strait is a northern arm of the Labrador Sea. It lies between mid-western Greenland and Nunavut, Canada's Baffin Island. The strait was named for the English explorer John Davis , who explored the area while seeking a Northwest Passage....

 [The parallel of 60° North
60th parallel north
The 60th parallel north is a circle of latitude that is 60 degrees north of the Earth's equatorial plane. It crosses Europe, Asia, the Pacific Ocean, North America, and the Atlantic Ocean....

 between Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

 and Labrador
Labrador
Labrador is the distinct, northerly region of the Canadian province of Newfoundland and Labrador. It comprises the mainland portion of the province, separated from the island of Newfoundland by the Strait of Belle Isle...

].

On the East: a line from Cape St. Francis 47°45′N 52°27′W (Newfoundland

Newfoundland and Labrador
Newfoundland and Labrador is the easternmost province of Canada. Situated in the country's Atlantic region, it incorporates the island of Newfoundland and mainland Labrador with a combined area of . As of April 2011, the province's estimated population is 508,400...

) to Cape Farewell
Cape Farewell, Greenland
Cape Farewell , is a headland on the southern shore of Egger Island, Greenland. Located at it is the southernmost extent of Greenland, projecting out into the North Atlantic Ocean and the Labrador Sea on the same latitude as Stockholm and the Scottish Shetland Islands. Egger and the associated...

 (Greenland).

On the West: the East Coast of Labrador and Newfoundland and the Northeast limit of the Gulf of St. Lawrence

Gulf of Saint Lawrence
The Gulf of Saint Lawrence , the world's largest estuary, is the outlet of North America's Great Lakes via the Saint Lawrence River into the Atlantic Ocean...

 – a line running from Cape Bauld
Cape Bauld
Cape Bauld is a headland located at the northeasternmost point of Great Northern Peninsula on the island of Newfoundland in the Canadian province of Newfoundland and Labrador....

 (North point of Kirpon Island
Quirpon Island
Quirpon Island is a small Canadian island off the northeastern tip of Newfoundland's Great Northern Peninsula in the province of Newfoundland and Labrador....

, 51°40′N 55°25′W) to the East extreme of Belle Isle
Belle Isle (Newfoundland and Labrador)
Belle Isle is an uninhabited island just off the coast of Labrador and north of Newfoundland at the Atlantic entrance to the Strait of Belle Isle which takes its name...

 and on to the Northeast Ledge (52°02′N 55°15′W). Thence a line joining this ledge with the East extreme of Cape St. Charles
Cape St. Charles
Cape St. Charles is a headland on the coast of Labrador in the Canadian province of Newfoundland and Labrador. At longitude 55°37'15"W it is the most easterly point on the continental North America....

 (52°13'N) in Labrador.

Geography, geology and bathymetry




The Labrador Sea is about 3400 m (11,155 ft) deep and 1000 km (621 mi) wide where it joins the Atlantic Ocean. It becomes shallower, to less than 700 m (2,297 ft) towards Baffin Bay (see depth map) and passes into the 300 km wide Davis Strait
Davis Strait
Davis Strait is a northern arm of the Labrador Sea. It lies between mid-western Greenland and Nunavut, Canada's Baffin Island. The strait was named for the English explorer John Davis , who explored the area while seeking a Northwest Passage....

. A 100–200 m deep turbidity current
Turbidity current
A turbidity current is a current of rapidly moving, sediment-laden water moving down a slope through water, or another fluid. The current moves because it has a higher density and turbidity than the fluid through which it flows...

 channel system, which is about 2–5 km wide and 3,800 km long, runs on the bottom of the sea, near its center from the Hudson Strait into the Atlantic. It is called the Northwest Atlantic Mid-Ocean Channel
Northwest Atlantic Mid-Ocean Channel
The Northwest Atlantic Mid-Ocean Channel is the main body of a turbidity current system of channels and canyons running on the sea bottom from the Hudson Strait, through the Labrador Sea and ending at the Sohm Abyssal Plain in the Atlantic Ocean. Contrary to most other such systems which fan away...

 (NAMOC) and is one of the world's longest drainage systems of Pleistocene age. It appears as a submarine river bed with numerous tributaries and is maintained by high-density turbidity currents flowing within the levee
Levee
A levee, levée, dike , embankment, floodbank or stopbank is an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels...

s.

The water temperature varies between –1 °C in winter and 5–6 °C in summer. The salinity is relatively low, at 31–34.9 parts per thousand. Two-thirds of the sea is covered in ice in winter. Tides are semi-diurnal
Earth tide
Earth tide is the sub-meter motion of the Earth of about 12 hours or longer caused by Moon and Sun gravitation, also called body tide which is the largest contribution globally. The largest body tide contribution is from the semidiurnal constituents, but there are also significant diurnal...

 (i.e. occur twice a day), reaching 4 meters.

There is an anticlockwise water circulation in the sea. It is initiated by the East Greenland Current
East Greenland Current
The East Greenland Current is a cold, low salinity current that extends from Fram Strait to Cape Farewell . The current is located off the eastern coast of Greenland along the Greenland continental margin. The current cuts through the Nordic Seas and through the Denmark Strait...

 and continued by the West Greenland Current
West Greenland Current
The West Greenland Current is a weak cold water current that flows to the north along the west coast of Greenland. The current results from the movement of water flowing around the southernmost point of Greenland caused by the East Greenland Current....

, which brings warmer, more saline waters northwards, along the Greenland coasts up to the Baffin Bay. Then, the Baffin Island Current
Baffin Island Current
Baffin Island Current is an ocean current running south down the western side of Baffin Bay in the Arctic Ocean, along Baffin Island. Its sources are the West Greenland Current and outflow from the Arctic Ocean. Its speed is approximately per day.- See also :* Labrador Current* East Greenland...

 and Labrador Current
Labrador Current
The Labrador Current is a cold current in the North Atlantic Ocean which flows from the Arctic Ocean south along the coast of Labrador and passes around Newfoundland, continuing south along the east coast of Nova Scotia...

 transport cold and less saline water southward along the Canadian coast. These currents carry numerous icebergs and therefore hinder navigation and exploration of the gas fields beneath the sea bed. The speed of the Labrador current is typically 0.3–0.5 m/s, but can reach 1 m/s in some areas, whereas the Baffin Current is somewhat slower at about 0.2 m/s. The Labrador Current maintains the water temperature at 0 °C and salinity between 30 and 34 parts per thousand.

The sea provides a significant part of the North Atlantic Deep Water
North Atlantic Deep Water
North Atlantic Deep Water is a water mass that forms in the North Atlantic Ocean. It is largely formed in the Labrador Sea and in the Greenland Sea by the sinking of highly saline, dense overflow water from the Greenland Sea...

 (NADW) – a cold water mass that flows at great depth along the western edge of the North Atlantic, spreading out to form the largest identifiable water mass in the World Ocean
World Ocean
The World Ocean, world ocean, or global ocean, is the interconnected system of the Earth's oceanic waters, and comprises the bulk of the hydrosphere, covering almost 71% of the Earth's surface, with a total volume of 1.332 billion cubic kilometres.The unity and continuity of the World Ocean, with...

. The NADW consists of three parts of different origin and salinity, and the top one, the Labrador Sea Water (LSW), is formed in the Labrador Sea. This part occurs at a medium depth and has a relatively low salinity (34.84–34.89 parts per thousand), low temperature (3.3–3.4 °C) and high oxygen content compared to the layers above and below it. LSW also has a relatively low vorticity, i.e. the tendency to form vortices, than any other water in North Atlantic that reflects its high homogeneity. It has a potential density of 27.76–27.78 mg/cm3 relatively to the surface layers, meaning it is denser, and thus sinks under the surface and remains homogeneous and unaffected by the surface fluctuations.

Fauna


The northern and western parts of the Labrador Sea are covered in ice between December and June. The drift ice
Drift ice
Drift ice is ice that floats on the surface of the water in cold regions, as opposed to fast ice, which is attached to a shore. Usually drift ice is carried along by winds and sea currents, hence its name, "drift ice"....

 serves as a breeding ground for seals in early spring. The sea is also a feeding ground for Atlantic salmon
Atlantic salmon
The Atlantic salmon is a species of fish in the family Salmonidae, which is found in the northern Atlantic Ocean and in rivers that flow into the north Atlantic and the north Pacific....

 and several marine mammal species. Shrimp fisheries
Shrimp fishery
A shrimp fishery is a fishery directed toward harvesting either shrimp or prawns. .-Commercial shrimping:...

 began in 1978 and intensified toward 2000, as well as cod fishing. However, the cod fishing rapidly depleted the fish population in the 1990s near the Labrador and West Greenland banks and was therefore halted in 1992. Other fishery targets include haddock
Haddock
The haddock , also known as the offshore hake, is a marine fish distributed on both sides of the North Atlantic. Haddock is a popular food fish and is widely fished commercially....

, Atlantic herring
Atlantic herring
Atlantic herring is a fish in the family Clupeidae. It is one of the most abundant fish species on earth. Herring can be found on both sides of the Atlantic Ocean, congregating in large schools. They can grow up to in length and weigh more than...

, lobster
Lobster
Clawed lobsters comprise a family of large marine crustaceans. Highly prized as seafood, lobsters are economically important, and are often one of the most profitable commodities in coastal areas they populate.Though several groups of crustaceans are known as lobsters, the clawed lobsters are most...

 and several species of flatfish
Flatfish
The flatfish are an order of ray-finned fish, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through and around the head during development...

 and pelagic fish
Pelagic fish
Pelagic fish live near the surface or in the water column of coastal, ocean and lake waters, but not on the bottom of the sea or the lake. They can be contrasted with demersal fish, which do live on or near the bottom, and reef fish which are associated with coral reefs.The marine pelagic...

 such as sand lance
Sand lance
A sand lance or sandlance is a fish belonging to the family Ammodytidae. Several species of sand lance are commonly known as "sand eels" or "sandeels", though they are not related to true eels. Another variant name is launce, and all names of the fish are references to its slender body and...

 and capelin
Capelin
The capelin or caplin, Mallotus villosus, is a small forage fish of the smelt family found in the Atlantic and Arctic oceans. In summer, it grazes on dense swarms of plankton at the edge of the ice shelf. Larger capelin also eat a great deal of krill and other crustaceans...

. They are most abundant in the southern parts of the sea.

Beluga whales, while abundant to the north, in the Baffin Bay
Baffin Bay
Baffin Bay , located between Baffin Island and the southwest coast of Greenland, is a marginal sea of the North Atlantic Ocean. It is connected to the Atlantic via Davis Strait and the Labrador Sea...

, where their population reaches 20,000, are rare in the Labrador Sea, especially since 1950s. The sea contains one of the two major stocks of Sei whale
Sei Whale
The sei whale , Balaenoptera borealis, is a baleen whale, the third-largest rorqual after the blue whale and the fin whale. It inhabits most oceans and adjoining seas, and prefers deep offshore waters. It avoids polar and tropical waters and semi-enclosed bodies of water...

s, the other one being the Scotian Shelf. Also common are minke
Minke Whale
Minke whale , or lesser rorqual, is a name given to two species of marine mammal belonging to a clade within the suborder of baleen whales. The minke whale was given its official designation by Lacepède in 1804, who described a dwarf form of Balænoptera acuto-rostrata...

 and bottlenose whale
Bottlenose whale
The Northern bottlenose whale is a species of the ziphiid family, one of two members of the Hyperoodon genus. The northern bottlenose was hunted heavily by Norway and Britain in the 19th and early 20th centuries...

s.


The Labrador Duck
Labrador Duck
The Labrador Duck was a striking black and white eider-like sea duck that was never common, and is believed to be the first bird to become extinct in North America after 1500. The last Labrador Duck is believed to have been seen at Elmira, New York on December 12, 1878; the last preserved specimen...

 was a common bird on the Canadian coast until 19th century, but is now extinct. Other coastal animals include the Labrador Wolf
Labrador Wolf
The Labrador Wolf is a subspecies of the gray wolf, Canis lupus, which is primarily found in Labrador and northern Quebec. It was stated by Peterson in 1966 that the Labrador Wolf is "closely related to...the extinct Newfoundland race C. l. beothucus"...

 (Canis lupus labradorius), caribou (Rangifer spp.), moose
Moose
The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...

 (Alces alces), black bear
American black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...

 (Ursus americanus), red fox
Red Fox
The red fox is the largest of the true foxes, as well as being the most geographically spread member of the Carnivora, being distributed across the entire northern hemisphere from the Arctic Circle to North Africa, Central America, and the steppes of Asia...

 (Vulpes vulpes), arctic fox
Arctic fox
The arctic fox , also known as the white fox, polar fox or snow fox, is a small fox native to Arctic regions of the Northern Hemisphere and is common throughout the Arctic tundra biome. The Greek word alopex, means a fox and Vulpes is the Latin version...

 (Alopex lagopus), wolverine
Wolverine
The wolverine, pronounced , Gulo gulo , also referred to as glutton, carcajou, skunk bear, or quickhatch, is the largest land-dwelling species of the family Mustelidae . It is a stocky and muscular carnivore, more closely resembling a small bear than other mustelids...

, snowshoe hare
Snowshoe Hare
The Snowshoe Hare , also called the Varying Hare, or Snowshoe Rabbit, is a species of hare found in North America. It has the name "snowshoe" because of the large size of its hind feet and the marks its tail leaves. The animal's feet prevent it from sinking into the snow when it hops and walks...

 (Lepus americanus), grouse
Grouse
Grouse are a group of birds from the order Galliformes. They are sometimes considered a family Tetraonidae, though the American Ornithologists' Union and many others include grouse as a subfamily Tetraoninae in the family Phasianidae...

 (Dendragapus spp.), osprey
Osprey
The Osprey , sometimes known as the sea hawk or fish eagle, is a diurnal, fish-eating bird of prey. It is a large raptor, reaching more than in length and across the wings...

 (Pandion haliaetus), raven (Corvus corax), ducks, geese, partridge and American wild pheasant.

Flora


Costal vegetation includes black spruce
Black Spruce
Picea mariana is a species of spruce native to northern North America, from Newfoundland west to Alaska, and south to northern New York, Minnesota and central British Columbia...

 (Picea mariana), tamarack, white spruce
White Spruce
Picea glauca is a species of spruce native to boreal forests in the north of North America, from central Alaska east to Newfoundland, and south to northern Montana, Minnesota, Wisconsin, Michigan, upstate New York, Vermont, New Hampshire, and Maine; there is also an isolated population in the...

 (P. glauca), dwarf birch
Dwarf Birch
Betula nana is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region.-Description:...

 (Betula spp.), aspen
Aspen
Populus section Populus, of the Populus genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by...

, willow
Willow
Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...

 (Salix spp.), ericaceous shrubs (Ericaceae
Ericaceae
The Ericaceae, commonly known as the heath or heather family, is a group of mostly calcifuge flowering plants. The family is large, with roughly 4000 species spread across 126 genera, making it the 14th most speciose family of flowering plants...

), cottongrass (Eriophorum spp.), sedge
Sedge
- Plants :* Acorus calamus, sweet flag, a plant in the Acoraceae family* Any of the plants in the family Cyperaceae- Animals :* A collective noun for several species of birds, including bitterns, cranes and herons* Sedge-fly, caddisfly- Other uses :...

 (Carex spp.), lichens and moss. Evergreen bushes of Labrador tea
Labrador tea
Labrador tea is a name commonly applied to three closely related species:* Rhododendron tomentosum ,...

, which is used to make herbal tea, are common in the area, both on the Greenland and Canadian coasts.