Labrador Sea
Labrador Sea | |
---|---|
Coordinates | 61°N 56°W / 61°N 56°W |
Type | Sea |
Basin countries | Canada and Greenland |
Max. length | c. 1,000 km (621 mi) |
Max. width | c. 900 km (559 mi) |
Surface area | 841,000 km2 (324,700 sq mi) |
Average depth | 1,898 m (6,227 ft) |
Max. depth | 4,316 m (14,160 ft) |
References | [1][2] |
The Labrador Sea (
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
History
The Labrador Sea formed upon separation of the
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.
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
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
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]
The
Flora
Coastal vegetation includes
References
- ^ a b "Labrador" (in Russian). Great Soviet Encyclopedia.
- ^ S2CID 140632779.
- ^ a b Encyclopædia Britannica. "Labrador Sea". Retrieved 2008-02-03.
- ISBN 978-0-632-04951-6. Retrieved 29 November 2010.
- S2CID 128436726.
- ISBN 87-02-01724-5
- ^ "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.
- ^ "Noms de lieux - Recherche par nom de toponyme".
- ^ "Ice-sheet sourced juxtaposed turbidite systems in Labrador Sea". Geoscience Canada. 24 (1): 3. 3 March 1997.
- .
- ISBN 0-412-79340-7.)
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:|work=
ignored (help)CS1 maint: multiple names: authors list (link - ISBN 3-540-66193-X.
- ^ a b Kenneth F. Drinkwater, R. Allyn Clarke. "Labrador Sea". The Canadian Encyclopedia. Archived from the original on 2018-08-02. Retrieved 2008-02-03.
- .
- ^ Encyclopædia Britannica. "Baffin Current". Retrieved 2010-02-03.
- ^ Encyclopædia Britannica. "Labrador Current". Retrieved 2010-02-03.
- ISBN 0-521-47895-2.
- ISSN 1520-0485.[permanent dead link]
- ^ National Research Council (U.S.) (1981). Maritime services to support polar resource development. pp. 6–7.
- ^ COSEWIC Assessment and Update Status Report on the Beluga Whale. Dsp-psd.pwgsc.gc.ca (2012-07-31). Retrieved on 2013-03-20.
- ISBN 0-7735-2881-4.
- JSTOR 4067622.
- JSTOR 1374306.
- doi:10.14430/arctic2062. Archived from the original(PDF) on 2020-07-01. Retrieved 2010-09-02.
- ISBN 1-4068-0512-2.
- ^ a b "Eastern Canadian Shield taiga". Terrestrial Ecoregions. World Wildlife Fund.
- ^ Ledum groenlandicum Oeder – Labrador Tea. (PDF) . Retrieved on 2013-03-20.