page_title: Labrador Sea
section_title: Oceanography
hierarchical_section_title: Labrador Sea / Oceanography
context_page_description: The Labrador Sea 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. It has been described as a marginal sea of the Atlantic.
  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, 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.
context_section_description: 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. 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. It is called the Northwest Atlantic Mid-Ocean Channel (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 levees.
  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).
  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. 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, whereas the Baffin Current is somewhat slower at about 0.2 m/s (0.66 ft/s). The Labrador Current maintains the water temperature at 0 °C (32 °F) and salinity between 30 and 34 parts per thousand.
  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. 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.
caption: Major North Atlantic currents
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