Labrador Sea

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Labrador Sea
Labrador-sea-paamiut.jpg
Past sunset at Labrador Sea, off the coast of Paamiut, Greenland
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Labrador Sea
Labrador sea map.png
Coordinates 61°N56°W / 61°N 56°W / 61; -56 (Labrador Sea)
Type Sea
Basin  countries Canada and Greenland
Max. lengthc. 1,000 km (621 mi)
Max. widthc. 900 km (559 mi)
Surface area841,000 km2 (324,700 sq mi)
Average depth1,898 m (6,227 ft)
Max. depth4,316 m (14,160 ft)
References [1] [2]

The Labrador Sea (French : mer du Labrador; Danish : Labradorhavet) is an arm of the North Atlantic Ocean between the Labrador Peninsula and Greenland. The sea is flanked by continental shelves to the southwest, northwest, and northeast. It connects to the north with Baffin Bay through the Davis Strait. [3] It is a marginal sea of the Atlantic. [4] [5]

Contents

The sea formed upon separation of the North American Plate and Greenland Plate that started about 60 million years ago and stopped about 40 million years ago. It contains one of the world's largest turbidity current channel systems, the Northwest Atlantic Mid-Ocean Channel (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, 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.

Arctic cultures in history Arctic cultures 900-1500.png
Arctic cultures in history

History

The Labrador Sea formed upon separation of the North American Plate and Greenland Plate that started about 60 million years ago (Paleocene) and stopped about 40 million years ago. [2] A sedimentary basin, which is now buried under the continental shelves, formed during the Cretaceous. [2] Onset of magmatic sea-floor spreading was accompanied by volcanic eruptions of picrites and basalts in the Paleocene at the Davis Strait and Baffin Bay. [2]

Between about 500 BC and 1300 AD, the southern coast of the sea contained Dorset, Beothuk, and Inuit settlements; Dorset tribes were later replaced by Thule people. [6]

Extent

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The International Hydrographic Organization defines the limits of the Labrador Sea as follows: [7]

On the North: the South limit of Davis Strait [The parallel of 60° North between Greenland and Labrador].

On the East: a line from Cape St. Francis 47°45′N52°27′W / 47.750°N 52.450°W / 47.750; -52.450 (Cape St. Francis) (Newfoundland) to Cape Farewell (Greenland).

On the West: the East Coast of Labrador and Newfoundland and the Northeast limit of the Gulf of St. Lawrence – a line running from Cape Bauld (North point of Kirpon Island, 51°40′N55°25′W / 51.667°N 55.417°W / 51.667; -55.417 (Cape Bauld) ) to the East extreme of Belle Isle and on to the Northeast Ledge ( 52°02′N55°15′W / 52.033°N 55.250°W / 52.033; -55.250 (Belle Isle) ). Thence a line joining this ledge with the East extreme of Cape St. Charles (52°13'N) in Labrador.

Natural Resources Canada uses a slightly different definition, putting the northern boundary of the Labrador Sea on a straight line from a headland on Killiniq Island abutting Lady Job Harbour to Cape Farewell. [8]

Oceanography

Major North Atlantic currents LabradorCurrentus-coastguard.jpg
Major North Atlantic currents

The Labrador Sea is about 3,400 m (1,859 fathoms ; 11,155 feet ) deep and 1,000 km (621 miles ; 540 nautical miles ) wide where it joins the Atlantic Ocean. It becomes shallower, to less than 700 m (383 fathoms; 2,297 ft) towards Baffin Bay (see depth map) and passes into the 300 km (190 mi; 160 nmi) wide Davis Strait. [2] A 100–200 m (55–109 fathoms; 330–660 ft) deep turbidity current channel system, which is about 2–5 km (1.2–3.1 mi; 1.1–2.7 nmi) wide and 3,800 km (2,400 mi; 2,100 nmi) long, runs on the bottom of the sea, near its center from the Hudson Strait into the Atlantic. [9] [10] It is called the Northwest Atlantic Mid-Ocean Channel (NAMOC) and is one of the world's longest drainage systems of Pleistocene age. [11] It appears as a submarine river bed with numerous tributaries and is maintained by high-density turbidity currents flowing within the levees. [12]

The water temperature varies between −1 °C (30 °F) in winter and 5–6 °C (41–43 °F) 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 (i.e. occur twice a day), reaching 4 m (2.2 fathoms; 13 ft). [1]

There is an anticlockwise water circulation in the sea. It is initiated by the East Greenland Current and continued by the West Greenland Current, which brings warmer, more saline waters northwards, along the Greenland coasts up to the Baffin Bay. Then, the Baffin Island Current and Labrador Current 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. [3] [13] The speed of the Labrador current is typically 0.3–0.5 m/s (0.98–1.64 ft/s), but can reach 1 m/s (3.3 ft/s) in some areas, [14] whereas the Baffin Current is somewhat slower at about 0.2 m/s (0.66 ft/s). [15] The Labrador Current maintains the water temperature at 0 °C (32 °F) and salinity between 30 and 34 parts per thousand. [16]

The sea provides a significant part of the North Atlantic Deep Water (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. [17] 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 (37.9–38.1 °F)) 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. [18]

Fauna

The northern and western parts of the Labrador Sea are covered in ice between December and June. The drift ice serves as a breeding ground for seals in early spring. The sea is also a feeding ground for Atlantic salmon and several marine mammal species. Shrimp fisheries 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. [13] Other fishery targets include haddock, Atlantic herring, lobster and several species of flatfish and pelagic fish such as sand lance and capelin. They are most abundant in the southern parts of the sea. [19]

Beluga whales, while abundant to the north, in the Baffin Bay, where their population reaches 20,000, are rare in the Labrador Sea, especially since the 1950s. [20] The sea contains one of the two major stocks of Sei whales, the other one being the Scotian Shelf. Also common are minke and bottlenose whales. [21]

Close up of a Labrador tea flower Labrador Tea flower.jpg
Close up of a Labrador tea flower

The Labrador duck was a common bird on the Canadian coast until the 19th century, but is now extinct. [22] Other coastal animals include the Labrador wolf (Canis lupus labradorius), [23] [24] caribou (Rangifer spp.), moose (Alces alces), black bear (Ursus americanus), red fox (Vulpes vulpes), Arctic fox (Alopex lagopus), wolverine, snowshoe hare (Lepus americanus), grouse (Dendragapus spp.), osprey (Pandion haliaetus), raven (Corvus corax), ducks, geese, partridge and American wild pheasant. [25] [26]

Flora

Coastal vegetation includes black spruce (Picea mariana), tamarack, white spruce (P. glauca), dwarf birch (Betula spp.), aspen, willow (Salix spp.), ericaceous shrubs ( Ericaceae ), cottongrass (Eriophorum spp.), sedge (Carex spp.), lichens and moss. [26] Evergreen bushes of Labrador tea, which is used to make herbal teas, are common in the area, both on the Greenland and Canadian coasts. [27]

Related Research Articles

<span class="mw-page-title-main">Atlantic Ocean</span> Ocean between Europe, Africa and the Americas

The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about 85,133,000 km2 (32,870,000 sq mi). It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for separating the Old World of Africa, Europe, and Asia from the New World of the Americas.

<span class="mw-page-title-main">North Atlantic Deep Water</span> Deep water mass formed in the North Atlantic Ocean

North Atlantic Deep Water (NADW) is a deep water mass formed in the North Atlantic Ocean. Thermohaline circulation of the world's oceans involves the flow of warm surface waters from the southern hemisphere into the North Atlantic. Water flowing northward becomes modified through evaporation and mixing with other water masses, leading to increased salinity. When this water reaches the North Atlantic, it cools and sinks through convection, due to its decreased temperature and increased salinity resulting in increased density. NADW is the outflow of this thick deep layer, which can be detected by its high salinity, high oxygen content, nutrient minima, high 14C/12C, and chlorofluorocarbons (CFCs).

<span class="mw-page-title-main">Strait of Gibraltar</span> Strait connecting the Atlantic to the Mediterranean

The Strait of Gibraltar is a narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Europe from Africa. The two continents are separated by 13 kilometres of ocean at the Strait's narrowest point between Punta de Tarifa in Spain and Point Cires in Morocco. Ferries cross between the two continents every day in as little as 35 minutes. The Strait's depth ranges between 300 and 900 metres.

<span class="mw-page-title-main">Hudson Strait</span> Strait connecting the Atlantic Ocean to Hudson Bay in Canada

Hudson Strait in Nunavut links the Atlantic Ocean and the Labrador Sea to Hudson Bay in Canada. This strait lies between Baffin Island and Nunavik, with its eastern entrance marked by Cape Chidley in Newfoundland and Labrador and Nunavut and Resolution Island, off Baffin Island. The strait is about 750 km (470 mi) long with an average width of 125 km (78 mi), varying from 70 km (43 mi) at the eastern entrance to 240 km (150 mi) at Deception Bay.

<span class="mw-page-title-main">Gulf of St. Lawrence</span> Outlet of the North American Great Lakes via the St. Lawrence River into the Atlantic Ocean

The Gulf of St. Lawrence fringes the shores of the provinces of Quebec, New Brunswick, Nova Scotia, Prince Edward Island, Newfoundland and Labrador, in Canada, plus the islands Saint-Pierre and Miquelon, possessions of France, in North America.

<span class="mw-page-title-main">Drake Passage</span> Body of water between South America and the South Shetland Islands of Antarctica

The Drake Passage is the body of water between South America's Cape Horn, Chile, Argentina, and the South Shetland Islands of Antarctica. It connects the southwestern part of the Atlantic Ocean with the southeastern part of the Pacific Ocean and extends into the Southern Ocean. The passage is named after the 16th-century English explorer and privateer Sir Francis Drake.

<span class="mw-page-title-main">Ocean current</span> Directional mass flow of oceanic water generated by external or internal forces

An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, shoreline configurations, and interactions with other currents influence a current's direction and strength. Ocean currents are primarily horizontal water movements.

<span class="mw-page-title-main">Baffin Bay</span> Marginal sea between Greenland and Baffin Island, Canada

Baffin Bay, located between Baffin Island and the west coast of Greenland, is defined by the International Hydrographic Organization as a marginal sea of the Arctic Ocean. It is sometimes considered a sea of the North Atlantic Ocean. It is connected to the Atlantic via Davis Strait and the Labrador Sea. The narrower Nares Strait connects Baffin Bay with the Arctic Ocean. The bay is not navigable most of the year because of the ice cover and high density of floating ice and icebergs in the open areas. However, a polynya of about 80,000 km2 (31,000 sq mi), known as the North Water, opens in summer on the north near Smith Sound. Most of the aquatic life of the bay is concentrated near that region.

<span class="mw-page-title-main">Davis Strait</span> Southern arm of the Arctic Ocean that lies between mid-western Greenland and Canadas Baffin Island

The Davis Strait is a southern arm of the Arctic Ocean that lies north of the Labrador Sea. It lies between mid-western Greenland and Baffin Island in Nunavut, Canada. To the north is Baffin Bay. The strait was named for the English explorer John Davis (1550–1605), who explored the area while seeking a Northwest Passage. By the 1650s it was used for whale hunting.

<span class="mw-page-title-main">East Greenland Current</span> Current from Fram Strait to Cape Farewell off the eastern coat of Greenland

The East Greenland Current (EGC) is a cold, low-salinity current that extends from Fram Strait (~80N) to Cape Farewell (~60N). 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. The current is of major importance because it directly connects the Arctic to the Northern Atlantic, it is a major contributor to sea ice export out of the Arctic, and it is a major freshwater sink for the Arctic.

<span class="mw-page-title-main">Labrador Current</span> Cold current in the Atlantic ocean along the coasts of Labrador, Newfoundland and Nova Scotia

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 Canada near Nova Scotia. Near Nova Scotia, this cold water current meets the warm northward moving Gulf Stream. The combination of these two currents produces heavy fogs and has also created one of the richest fishing grounds in the world.

<span class="mw-page-title-main">Greenland Sea</span> Body of water

The Greenland Sea is a body of water that borders Greenland to the west, the Svalbard archipelago to the east, Fram Strait and the Arctic Ocean to the north, and the Norwegian Sea and Iceland to the south. The Greenland Sea is often defined as part of the Arctic Ocean, sometimes as part of the Atlantic Ocean. However, definitions of the Arctic Ocean and its seas tend to be imprecise or arbitrary. In general usage the term "Arctic Ocean" would exclude the Greenland Sea. In oceanographic studies the Greenland Sea is considered part of the Nordic Seas, along with the Norwegian Sea. The Nordic Seas are the main connection between the Arctic and Atlantic oceans and, as such, could be of great significance in a possible shutdown of thermohaline circulation. In oceanography the Arctic Ocean and Nordic Seas are often referred to collectively as the "Arctic Mediterranean Sea", a marginal sea of the Atlantic.

<span class="mw-page-title-main">Northwest Atlantic Marine Ecozone</span> Canadian marine ecozone

The Northwest Atlantic Marine Ecozone, as defined by the Commission for Environmental Cooperation (CEC), is a Canadian marine ecozone forming a transitional region between the cold northern waters of the Arctic Ocean and the more temperate waters in its southern extent.

<span class="mw-page-title-main">Arctic Ocean</span> Ocean in the north polar region

The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately 14,060,000 km2 (5,430,000 sq mi) and is known as one of the coldest of oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea. It has also been described as an estuary of the Atlantic Ocean. It is also seen as the northernmost part of the all-encompassing World Ocean.

<span class="mw-page-title-main">West Spitsbergen Current</span> Warm, salty current that runs poleward just west of Spitsbergen

The West Spitsbergen Current (WSC) is a warm, salty current that runs poleward just west of Spitsbergen,, in the Arctic Ocean. The WSC branches off the Norwegian Atlantic Current in the Norwegian Sea. The WSC is of importance because it drives warm and salty Atlantic Water into the interior Arctic. The warm and salty WSC flows north through the eastern side of Fram Strait, while the East Greenland Current (EGC) flows south through the western side of Fram Strait. The EGC is characterized by being very cold and low in salinity, but above all else it is a major exporter of Arctic sea ice. Thus, the EGC combined with the warm WSC makes the Fram Strait the northernmost ocean area having ice-free conditions throughout the year in all of the global ocean.

The Great Salinity Anomaly (GSA) originally referred to an event in the late 1960s to early 1970s where a large influx of freshwater from the Arctic Ocean led to a salinity anomaly in the northern North Atlantic Ocean, which affected the Atlantic meridional overturning circulation. Since then, the term "Great Salinity Anomaly" has been applied to successive occurrences of the same phenomenon, including the Great Salinity Anomaly of the 1980s and the Great Salinity Anomaly of the 1990s. The Great Salinity Anomalies were advective events, propagating to different sea basins and areas of the North Atlantic, and is on the decadal-scale for the anomalies in the 1970s, 1980s, and 1990s.

<span class="mw-page-title-main">Labrador Sea Water</span> Water mass formed by convective processes in the Labrador Sea

Labrador Sea Water is an intermediate water mass characterized by cold water, relatively low salinity compared to other intermediate water masses, and high concentrations of both oxygen and anthropogenic tracers. It is formed by convective processes in the Labrador Sea located between Greenland and the northeast coast of the Labrador Peninsula. Deep convection in the Labrador Sea allows colder water to sink forming this water mass, which is a contributor to the upper layer of North Atlantic Deep Water. North Atlantic Deep Water flowing southward is integral to the Atlantic Meridional Overturning Circulation. The Labrador Sea experiences a net heat loss to the atmosphere annually.

<span class="mw-page-title-main">Canadian Arctic Rift System</span> North American geological structure

The Canadian Arctic Rift System is a major North American geological structure extending from the Labrador Sea in the southeast through Davis Strait, Baffin Bay and the Arctic Archipelago in the northwest. It consists of a series of interconnected rifts that formed during the Paleozoic, Mesozoic and Cenozoic eras. Extensional stresses along the entire length of the rift system have resulted in a variety of tectonic features, including grabens, half-grabens, basins and faults.

<span class="mw-page-title-main">Mediterranean outflow</span>

The Mediterranean Outflow is a current flowing from the Mediterranean Sea towards the Atlantic Ocean through the Strait of Gibraltar. Once it has reached the western side of the Strait of Gibraltar, it divides into two branches, one flowing westward following the Iberian continental slope, and another returning to the Strait of Gibraltar circulating cyclonically. In the Strait of Gibraltar and in the Gulf of Cádiz, the Mediterranean Outflow core has a width of a few tens of km. Through its nonlinear interactions with tides and topography, as it flows out of the Mediterranean basin it undergoes such strong mixing that the water masses composing this current become indistinguishable upon reaching the western side of the strait.

<span class="mw-page-title-main">Irminger Rings</span> Ocean eddies in Labrador Sea which influence deep convection

Irminger Rings (IRs) are mesoscale ocean eddies that are formed off the West coast of Greenland and travel southwestwards through the Labrador Sea. Most IRs are anti-cyclonic. There is considerable interest in researching IRs, because they have been hypothesized to influence deep convection in the Labrador sea, and therefore the formation of deep water.

References

  1. 1 2 "Labrador" (in Russian). Great Soviet Encyclopedia.
  2. 1 2 3 4 5 Wilson, R. C. L; London, Geological Society of (2001). "Non-volcanic rifting of continental margins: a comparison of evidence from land and sea". Geological Society, London, Special Publications. 187 (1): 77. Bibcode:2001GSLSP.187...77C. doi:10.1144/GSL.SP.2001.187.01.05. ISBN   978-1-86239-091-1. S2CID   140632779.
  3. 1 2 Encyclopædia Britannica. "Labrador Sea" . Retrieved 2008-02-03.
  4. ↑ Calow, Peter (12 July 1999). Blackwell's concise encyclopedia of environmental management. Wiley-Blackwell. p. 7. ISBN   978-0-632-04951-6 . Retrieved 29 November 2010.
  5. ↑ Spall, Michael A. (2004). "Boundary Currents and Watermass Transformation in Marginal Seas". J. Phys. Oceanogr. 34 (5): 1197–1213. Bibcode:2004JPO....34.1197S. doi:10.1175/1520-0485(2004)034<1197:BCAWTI>2.0.CO;2. S2CID   128436726.
  6. ↑ Grønlands forhistorie, ed. Hans Christian Gulløv, Gyldendal 2005, ISBN   87-02-01724-5
  7. ↑ "Limits of Oceans and Seas, 3rd edition" (PDF). International Hydrographic Organization. 1953. Archived from the original (PDF) on 8 October 2011. Retrieved 28 December 2020.
  8. ↑ "Noms de lieux - Recherche par nom de toponyme".
  9. ↑ "Ice-sheet sourced juxtaposed turbidite systems in Labrador Sea". Geoscience Canada. 24 (1): 3. 3 March 1997.
  10. ↑ Reinhard Hesse And Allan Rakofsky (1992). "Deep-Sea Channel/Submarine-Yazoo System of the Labrador Sea: A New Deep-Water Facies Model (1)". AAPG Bulletin. 76. doi:10.1306/BDFF88A8-1718-11D7-8645000102C1865D.
  11. ↑ Hesse, R., Klauck, I., Khodabakhsh, S. & Ryan, W. B. F. (1997). Thomas A. Davies (ed.). Glaciated continental margins: an atlas of acoustic images. Springer. p. 286. ISBN   0-412-79340-7.{{cite book}}: |work= ignored (help)CS1 maint: multiple names: authors list (link)
  12. ↑ Einsele, Gerhard (2000). Sedimentary basins: evolution, facies, and sediment budget. Springer. p. 234. ISBN   3-540-66193-X.
  13. 1 2 Kenneth F. Drinkwater, R. Allyn Clarke. "Labrador Sea". The Canadian Encyclopedia. Archived from the original on 2018-08-02. Retrieved 2008-02-03.
  14. ↑ Petrie, B.; A. Isenor (1985). "The near-surface circulation and exchange in the Newfoundland Grand Banks region". Atmosphere-Ocean. 23 (3): 209–227. doi: 10.1080/07055900.1985.9649225 .
  15. ↑ Encyclopædia Britannica. "Baffin Current" . Retrieved 2010-02-03.
  16. ↑ Encyclopædia Britannica. "Labrador Current" . Retrieved 2010-02-03.
  17. ↑ Wallace Gary Ernst (2000). Earth systems: processes and issues. Cambridge University Press. p. 179. ISBN   0-521-47895-2.
  18. ↑ Talley, L.D.; McCartney, M.S. (1982). "Distribution and Circulation of Labrador Sea Water" (PDF). Journal of Physical Oceanography. 12 (11): 1189. Bibcode:1982JPO....12.1189T. doi:10.1175/1520-0485(1982)012<1189:DACOLS>2.0.CO;2. ISSN   1520-0485.[ permanent dead link ]
  19. ↑ National Research Council (U.S.) (1981). Maritime services to support polar resource development. pp. 6–7.
  20. ↑ COSEWIC Assessment and Update Status Report on the Beluga Whale. Dsp-psd.pwgsc.gc.ca (2012-07-31). Retrieved on 2013-03-20.
  21. ↑ Anthony Bertram Dickinson; Chesley W. Sanger (2005). Twentieth-century shore-station whaling in Newfoundland and Labrador. McGill-Queen's Press – MQUP. pp. 16–17. ISBN   0-7735-2881-4.
  22. ↑ Ducher, William (1894). "The Labrador Duck – another specimen, with additional data respecting extant specimens" (PDF). Auk. 11 (1): 4–12. doi:10.2307/4067622. JSTOR   4067622.
  23. ↑ E. A. Goldman (1937). "The Wolves of North America". Journal of Mammalogy. 18 (1): 37–45. doi:10.2307/1374306. JSTOR   1374306.
  24. ↑ G.R. Parker; S. Luttich (1986). "Characteristics of the Wolf (Canis lupus lubrudorius Goldman) in Northern Quebec and Labrador" (PDF). Arctic. 39 (2): 145–149. doi:10.14430/arctic2062. Archived from the original (PDF) on 2020-07-01. Retrieved 2010-09-02.
  25. ↑ Anonymous (2006). The Moravians in Labrador. Echo Library. pp. 9–11. ISBN   1-4068-0512-2.
  26. 1 2 "Eastern Canadian Shield taiga". Terrestrial Ecoregions. World Wildlife Fund.
  27. ↑ Ledum groenlandicum Oeder – Labrador Tea. (PDF) . Retrieved on 2013-03-20.
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