Various ice shelves, including the Filchner-Ronne Ice Shelf, fringe the Weddell sea. Some of the ice shelves on the east side of theAntarctic Peninsula, which formerly covered roughly 10,000 square kilometres (3,900 sq mi) of the Weddell Sea, had completely disappeared by 2002.[2] The Weddell Sea has been deemed by scientists to have the clearest water of any sea. Researchers from theAlfred Wegener Institute, on finding aSecchi disc visible at a depth of 80 metres (260 ft) on13 October 1986, ascertained that the clarity corresponded to that of distilled water.[3]
In his 1950 bookThe White Continent, historian Thomas R. Henry writes: "The Weddell Sea is, according to the testimony of all who have sailed through its berg-filled waters, the most treacherous and dismal region on Earth. TheRoss Sea is relatively peaceful, predictable, and safe."[4] He continues for an entire chapter, relating myths of the green-hairedmerman sighted in the sea's icy waters, the inability of crews to navigate a path to the coast until 1949, and treacherous "flash freezes" that left ships, such asErnest Shackleton'sEndurance, at the mercy of theice floes.
The sea is named after the Scottish sailorJames Weddell (1787-1834), who entered the sea in 1823 and originally named it after KingGeorge IV; it was renamed in Weddell's honour in 1900.[5] Also in 1823, the American sealing captainBenjamin Morrell claimed to have seen land some 10–12° east of the sea's actual eastern boundary. He called thisNew South Greenland, but its existence was disproved when the sea was more fully explored in the early 20th century. Morrell got as far south as74°S; the furthest southern penetration since Weddell but before the modern era was made byWilliam Speirs Bruce in 1903.
The Weddell Sea is an important area of deep water mass formation throughcabbeling, the main driving force of thethermohaline circulation. Deepwater masses are also formed through cabbeling in the North Atlantic and are caused by differences in temperature and salinity of the water. In the Weddell sea, this is brought about mainly by brine exclusion and wind cooling.
In 1823, British sailor James Weddell discovered the Weddell Sea.
TheAntarctic Sound is named after theexpeditionship ofOtto Nordenskiöld. The sound that separates the tip of the Antarctic Peninsula fromDundee Island is also referred to as "Iceberg Alley", because of the huge icebergs that are often seen here.Snow Hill, located east of the Antarctic Peninsula is almost completely snow-capped, hence its name. The expedition built a cabin on the island in 1902, where Nordenskiöld and three members of the expedition had to spend two winters after his ship was sunk in 1903.
In 1915,Ernest Shackleton's ship,Endurance, also got trapped and was later crushed by ice in this sea. After 15 months on the pack-ice Shackleton and his men managed to reachElephant Island and safely returned home.[6] In March 2022, it was announced that the well-preserved wreck of theEndurance had been discovered four miles (6.4 km) from its anticipated location, at a depth of 3,008 metres (9,869 ft).[7]
As with other neighboring parts of Antarctica, the Weddell Sea shares a common geological history with southernmostSouth America. In southernPatagonia at the onset of theAndean orogeny in theJurassicextensional tectonics created theRocas Verdes Basin, aback-arc basin whose surviving southeastward extension forms the Weddell Sea.[8][9] In theLate Cretaceous the tectonic regime of Rocas Verdes Basin changed leading to its transformation into a compressionalforeland basin – theMagallanes Basin – in theCenozoic.[8] While this happened in South America the Weddell Sea part of the basin escaped compressional tectonics and remained an oceanic basin.[9]
The Weddell Sea is one of few locations in theWorld Ocean where deep and bottom water masses are formed to contribute to the globalthermohaline circulation which has been warming slowly over the last decade.[when?][10] The characteristics of exported water masses result from complex interactions between surface forcing, significantly modified by sea ice processes, ocean dynamics at the continental shelf break, and slope and sub-ice shelf water mass transformation.[11]
Circulation in the western Weddell Sea is dominated by a northward flowing current. This northward current is the western section of a primarily wind-driven, cyclonic gyre called theWeddell Gyre. This northward flow serves as the primary force of departure of water from the Weddell Sea, a major site of ocean water modification and deep water formation, to the remainder of the World Ocean. The Weddell Gyre is a cold, low salinity surface layer separated by a thin, weakpycnocline from a thick layer of relatively warm and salty water referred to as Weddell Deep Water (WDW), and a cold bottom layer.[12]
Circulation in the Weddell Sea has proven difficult to quantify. Geopotential surface heights above the 1000 dB level, computed using historical data, show only very weak surface currents. Similar computations carried out using more closely spaced data also showed small currents. Closure of the gyre circulation was assumed to be driven bySverdrup transport. The Weddell Sea is a major site for deep water formation.
Thus, in addition to a wind-driven gyre component of the boundary current, a deeper circulation whose dynamics and transports reflect an input of dense water in the southern and southwestern Weddell Sea are expected. Available data does not lend to the quantification of the volume transports associated with this western boundary region, or to the determination of deep convective circulation along the western boundary.[12]
The predominance of strong surface winds parallel to the narrow and tall mountain range of the Antarctic Peninsula is a remarkable feature of weather and climate in the area of the western Weddell Sea. The winds carry cold air toward lower latitudes and turn into southwesterlies farther north.
These winds are of interest not only because of their effect on the temperature regime east of the peninsula but also because they force the drift of ice northeastward into the South Atlantic Ocean as the last branch of the clockwise circulation in the lower layers of the atmosphere along the coasts of the Weddell Sea. The sharp contrast between the wind, temperature, and ice conditions of the two sides of the Antarctic Peninsula has been well known for many years.[13]
Strong surface winds directed equatorward along the east side of the Antarctic Peninsula can appear in two different types of synoptic-meteorological situations: an intense cyclone over the central Weddell Sea, a broad east to west flow of stable cold air in the lowest 500-to-1000-metre layer of the atmosphere over the central and/or southern Weddell Sea toward the peninsula. These conditions lead to cold air piling up on the east edge of the mountains. This process leads to the formation of a high-pressure ridge over the peninsula (mainly east of the peak) and, therefore, a deflection of the originally westward current of air to the right, along the mountain wall.[13]
TheAdélie penguin is the dominant penguin species in this remote area because of their adaptation to the harsh environment. A colony of more than 100,000 pairs of Adélies can be found on volcanicPaulet Island.
Around 1997, the northernmostemperor penguin colony was discovered just south of Snowhill Island in the Weddell Sea. As the Weddell Sea is often clogged with heavy pack-ice, strong ice-class vessels equipped with helicopters are required to reach this colony.[6]
In 2021,sponges and other unidentified suspension feeders were reported to have been found growing under theFilchner-Ronne Ice Shelf on a boulder at a depth of 1,233 m (872 of which were ice), 260 km from open water.[14]
^abGhiglione, M. C. (2016). "Orogenic Growth of the Fuegian Andes (52–56°) and Their Relation to Tectonics of the Scotia Arc". In Folguera, A.; et al. (eds.).Growth of the Southern Andes. Springer. pp. 241–267.ISBN9783319230603.
Smith, M. (2004),Sir James Wordie, Polar Crusader: Exploring the Arctic and Antarctic, Birlinn,ISBN9781841582924
Schwerdtfeger, W. (1979). "Meteorological aspects of the drift of ice from the Weddell Sea toward the mid-latitude westerlies".J. Geophys. Res.84 (C10):6321–6328.Bibcode:1979JGR....84.6321S.doi:10.1029/JC084iC10p06321.
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