Labrador Sea

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 has been described as a marginal sea of the Atlantic.[4][5]

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 900-1500
Arctic cultures in history
Labrador Sea
Labrador-sea-paamiut
Past sunset at Labrador Sea, off the coast of Paamiut, Greenland, in July 2009.
Labradorseamap
Coordinates61°N 56°W / 61°N 56°WCoordinates: 61°N 56°W / 61°N 56°W
TypeSea
Basin countriesCanada, 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]

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

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′N 52°27′W / 47.750°N 52.450°W (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′N 55°25′W / 51.667°N 55.417°W) to the East extreme of Belle Isle and on to the Northeast Ledge (52°02′N 55°15′W / 52.033°N 55.250°W). Thence a line joining this ledge with the East extreme of Cape St. Charles (52°13'N) in Labrador.

Geography, geology and bathymetry

LabradorCurrentus-coastguard
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.[8][9] It is called the Northwest Atlantic Mid-Ocean Channel (NAMOC) and is one of the world's longest drainage systems of Pleistocene age.[10] It appears as a submarine river bed with numerous tributaries and is maintained by high-density turbidity currents flowing within the levees.[11]

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][12] 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,[13] whereas the Baffin Current is somewhat slower at about 0.2 m/s (0.66 ft/s).[14] The Labrador Current maintains the water temperature at 0 °C (32 °F) and salinity between 30 and 34 parts per thousand.[15]

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.[16] 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.[17]

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.[12] 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.[18]

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.[19] 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.[20]

Labrador Tea flower
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.[21] Other coastal animals include the Labrador wolf (Canis lupus labradorius),[22][23] 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.[24][25]

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.[25] Evergreen bushes of Labrador tea, which is used to make herbal teas, are common in the area, both on the Greenland and Canadian coasts.[26]

References

  1. ^ a b "Labrador" (in Russian). Great Soviet Encyclopedia.
  2. ^ a b c d e 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: 77. doi:10.1144/GSL.SP.2001.187.01.05. ISBN 978-1-86239-091-1.
  3. ^ a b 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. doi:10.1175/1520-0485(2004)034<1197:BCAWTI>2.0.CO;2.
  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. Retrieved 6 February 2010.
  8. ^ "Ice-sheet sourced juxtaposed turbidite systems in Labrador Sea". Geoscience Canada. 24 (1): 3.
  9. ^ 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.
  10. ^ Hesse, R., Klauck, I., Khodabakhsh, S. & Ryan, W. B. F. (1997). Thomas A. Davies (ed.). Glaciated continental margins: an atlas of acoustic images. Glacimarine drainage systems in the deep-sea: the NAMOC system of the Labrador Sea and its sibling. Springer. p. 286. ISBN 0-412-79340-7.CS1 maint: Multiple names: authors list (link)
  11. ^ Einsele, Gerhard (2000). Sedimentary basins: evolution, facies, and sediment budget. Springer. p. 234. ISBN 3-540-66193-X.
  12. ^ a b Kenneth F. Drinkwater, R. Allyn Clarke. "Labrador Sea". The Canadian Encyclopedia. Retrieved 2008-02-03.
  13. ^ Petrie, B.; A. Isenor (1985). "The near-surface circulation and exchange in the Newfoundland Grand Banks region" (PDF). Atmosphere-Ocean. 23 (3): 209–227. doi:10.1080/07055900.1985.9649225. Archived from the original (PDF) on November 21, 2010.
  14. ^ Encyclopædia Britannica. "Baffin Current". Retrieved 2010-02-03.
  15. ^ Encyclopædia Britannica. "Labrador Current". Retrieved 2010-02-03.
  16. ^ Wallace Gary Ernst (2000). Earth systems: processes and issues. Cambridge University Press. p. 179. ISBN 0-521-47895-2.
  17. ^ Talley, L.D.; McCartney, M.S. (1982). "Distribution and Circulation of Labrador Sea Water" (PDF). Journal of Physical Oceanography. 12 (11): 1189. doi:10.1175/1520-0485(1982)012<1189:DACOLS>2.0.CO;2. ISSN 1520-0485.
  18. ^ National Research Council (U.S.) (1981). Maritime services to support polar resource development. pp. 6–7.
  19. ^ COSEWIC Assessment and Update Status Report on the Beluga Whale. Dsp-psd.pwgsc.gc.ca (2012-07-31). Retrieved on 2013-03-20.
  20. ^ 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.
  21. ^ Ducher, William (1894). "The Labrador Duck – another specimen, with additional data respecting extant specimens" (PDF). Auk. 11 (1): 4–12. doi:10.2307/4067622.
  22. ^ E. A. Goldman (1937). "The Wolves of North America". Journal of Mammalogy. 18 (1): 37–45. doi:10.2307/1374306. JSTOR 1374306.
  23. ^ 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.
  24. ^ Anonymous, (2006). The Moravians in Labrador. pp. 9–11. ISBN 1-4068-0512-2.
  25. ^ a b "Eastern Canadian Shield taiga". Terrestrial Ecoregions. World Wildlife Fund.
  26. ^ Ledum groenlandicum Oeder – Labrador Tea. (PDF) . Retrieved on 2013-03-20.
Avingasittuit Siqinirsipangat Island

Avingasittuit Siqinirsipangat Island is one of the many uninhabited Canadian arctic islands in the Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea.

Other islands in the immediate vicinity include Holdridge Island, Lawson Island, Leading Island, and MacColl Island.

Christopher Hall Island

Christopher Hall Island is a Baffin Island offshore island located in the Canadian Arctic Archipelago in Nunavut's Qikiqtaaluk Region. The island lies in the Labrador Sea between Popham Bay and Neptune Bay, off the east coast of Hall Peninsula's Finger Land. The Leybourne Islands are to the south, while Jackson Island is to the north.

Clark Island (Nunavut)

Clark Island is one of the many uninhabited Canadian arctic islands in the Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea.

It is a member of the Button Islands and is situated 1.2 mi (1.9 km) west-southwest of the southern end of MacColl Island. Other islands in the immediate vicinity include Dolphin Island, Holdridge Island, King Island, Leading Island, and Niels Island.

Cumberland Sound

Cumberland Sound (French: Baie Cumberland; Inuit: Kangiqtualuk) (other names: Cumberland Straits; Hogarth Sound; Northumberland Inlet); Old Norse: ᚠᛁᛋᚦᚱᛁ ᚢᛒᚢᚴᚦᛁᛦ, fisþri ubukþiR), is an Arctic waterway in Qikiqtaaluk Region, Nunavut, Canada. It is a western arm of the Labrador Sea located between Baffin Island's Hall Peninsula and the Cumberland Peninsula. It is approximately 250 km (160 mi) long and 80 km (50 mi) wide.

Small islands litter the stretch of water which was formed from glacial activity and meltwater produced from the receding glacier.The only settlement located on the shore of the sound on the Cumberland Peninsula is Pangnirtung. John Davis, the English explorer, went part way up the sound in 1585.

Dolphin Island (Nunavut)

Dolphin Island is one of the many uninhabited Canadian arctic islands in Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea.

Dolphin Island, a member of the Button Islands, is small and lies southwest of Holdridge Island.Other islands in the immediate vicinity include Clark Island, Holdridge Island, King Island, Leading Island, and Niels Island.

Erhardt Island

Erhardt Island is one of the many uninhabited Canadian arctic islands in Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea. The island has an elevation of 107 m (351 ft) above sea level.

It is a member of the Button Islands and is situated 1.5 mi (2.4 km) west of MacColl Island. Other islands in the immediate vicinity include Clark Island, King Island, Lawson Island, Leading Island, and Observation Island.

Goodwin Island

Goodwin Island is one of the many uninhabited Canadian arctic islands in Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea.

The island, a member of the Button Islands, is situated west-northwest of Lacy Island. It has a peak of 178 m (584 ft).Other islands in the immediate vicinity include Erhardt Island, King Island, Lawson Island, MacColl Island, and Observation Island.

Holdridge Island

Holdridge Island is one of the many uninhabited Canadian arctic islands in Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea.

Holdridge Island's highest mount is 91 m (299 ft) above sea level.

It is a member of the Button Islands and is situated west of the southern end of Lawson Island. Other islands in the immediate vicinity include Dolphin Island, King Island, Leading Island, Niels Island, and Observation Island.

Hudson Island (Nunavut)

Hudson Island, measuring 13 km2 (5.0 sq mi) in area, is a Baffin Island offshore island located in the Canadian Arctic Archipelago in the territory of Nunavut. The uninhabited island lies in the Labrador Sea, east of Lupton Channel. Other islands also in the immediate vicinity of Blunt Peninsula (the tip of Hall Peninsula) include the Harper Islands, Lefferts Island, Bear Island, and Little Hall Island.

Ilikok Island

Ilikok Island is an uninhabited island in the Qikiqtaaluk Region of Nunavut, Canada. It is located in the Labrador Sea, off southeastern Baffin Island's Cumberland Peninsula. Muingmak Island is in the immediate vicinity.

Ilikok Island is 29 km2 (11 sq mi) in size.

Jackson Island (Nunavut)

Jackson Island is an irregularly shaped Baffin Island offshore island located in the Canadian Arctic Archipelago in Nunavut's Qikiqtaaluk Region. The uninhabited island lies in the Labrador Sea at the mouth of Neptune Bay, off the east coast of Hall Peninsula's Finger Land. Christopher Hall Island is to the southeast, while Moodie Island is to the northwest.

King Island (Nunavut)

King Island is one of the many uninhabited Canadian arctic islands in Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea.

King Island has a noticeable cliff on its southeastern side.

It is a member of the Button Islands and is situated southwest of MacColl Island. Other islands in the immediate vicinity include Clark Island, Holdridge Island, Leading Island, Niels Island, and Observation Island.

Lacy Island

Lacy Island is one of the many uninhabited Canadian arctic islands in Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea. The island, a member of the Button Islands, is situated in the northeast part of the grouping.

Other islands in the immediate vicinity include Goodwin Island, MacColl Island, Lawson Island, Erhardt Island, and Observation Island.

Leading Island

Leading Island is one of the many uninhabited Canadian arctic islands in Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea.

Leading Island, west of Holdridge Island, is a small islet with an elevation of only 9 m (30 ft) above sea level. It is a member of the Button Islands.Other islands in the immediate vicinity include Dolphin Island, King Island, Niels Island, and Observation Island.

Little Hall Island

Little Hall Island (also known as: Hall Smaller Island) is a Baffin Island offshore island located in the Canadian Arctic Archipelago in the territory of Nunavut. The island lies in the Labrador Sea a few kilometers north of its confluence with Davis Strait. Other islands also in the immediate vicinity of the tip of Hall Peninsula include the Harper Islands, Lefferts Island, Bear Island, and Hudson Island.

Muingmak Island

Muingmak Island is an uninhabited island in the Qikiqtaaluk Region of Nunavut, Canada. It is located in the Labrador Sea, off southeastern Baffin Island's Cumberland Peninsula. Ilikok Island is in the immediate vicinity.

Muingmak Island is 8 km2 (3.1 sq mi) in size.

Niels Island

Niels Island is one of the many uninhabited Canadian arctic islands in Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea.

Niels Island, a member of the Button Islands, is small and lies southwest of Holdridge Island.Other islands in the immediate vicinity include Clark Island, Dolphin Island, Holdridge Island, King Island, and Leading Island.

Observation Island (Nunavut)

Observation Island is one of the many uninhabited Canadian arctic islands in Qikiqtaaluk Region, Nunavut. It is located at the confluence of Hudson Strait and the Labrador Sea.

Other islands in the immediate vicinity include Holdridge Island, Lawson Island, Leading Island, and MacColl Island.

Rogers Island (Nunavut)

Rogers Island (variant: Roger Island) is a Baffin Island offshore island located in the Canadian Arctic Archipelago in the territory of Nunavut. The island lies in the Labrador Sea at the mouth of Cornelius Grinnell Bay between the Hall Peninsula and Beekman Peninsula. The significantly larger Allen Island is approximately 13 km (8.1 mi) to the north.

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