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60-488: The Weddell Sea plays an important role in the movement of the world's oceans. An important part of the Weddell Sea is Weddell Sea Bottom Water (WSBW). WSBW is a major contributor to Antarctic Bottom Water (AABW). While WSBW is considered part of AABW, the distinction comes in its potential temperature . The potential temperature of WSBW is -0.7 °C. At this temperature, the potential temperature vs. salinity chart shows

120-525: A 14-20 month lead time with influences from SAM at 14-20 month lead times as well. Warm ENSO events cause the increase of sea ice advection and more coastal polynyas which allows for more dense shelf water availability. These ENSO and SAM changes impact the WSBW 14–20 months later. Their research suggests that there needs to be large ENSO and SAM events in order for the anomalies in WSBW temperature can be noticed. These large fluctuations allow for warm and cold pulses in

180-406: A factor in this fast break-up being the powerful effects of water; ponds of meltwater formed on the surface during the near 24 hours of daylight in the summertime, flowed down into cracks and, acting like a multitude of wedges, levered the shelf apart. Other likely factors in the break-up were the higher ocean temperatures and the decline of the ice of the peninsula. In the austral winter of 2011,

240-560: A large expanse of sea ice formed over the embayment that was once covered by the land-fast shelf of fresh-water glacial ice of Larsen B. This enormous ice pack persisted through January 2022 when it suddenly broke-up over the course of a few days, "taking with it a Philadelphia-sized piece of the Scar Inlet Ice Shelf ," according to NASA scientists examining images from the Terra and Aqua satellites. As of July 2017 , Larsen C

300-461: A low-salinity, better oxygenated component confined to the outer rim of the Weddell Gyre , and a more saline, less oxygenated component observed farther into the gyre. The more saline WSBW is derived from the southwestern Weddell Sea, where high salinity shelf water is abundant. The less saline WSBW, like the more ventilated Weddell Sea Deep Water (WSDW), is derived from lower-salinity shelf water at

360-414: A mile) below the sea. The discovery was accidental. U.S. Antarctic Program scientists were in the north-western Weddell Sea investigating the sediment record in a deep glacial trough of roughly 1,000,000 square kilometres (390,000 sq mi) (twice the size of Texas or France ). Methane and hydrogen sulfide associated with cold seeps is suspected as the source of the chemical energy powering

420-515: A point farther north along the Antarctic Peninsula. It is important to distinguish between AABW and a subclass of this water mass, WSBW. WSBW is characterized by lower potential temperatures and larger near-bottom temperature gradients, suggesting recent formation in the southwestern and western Weddell Sea. As this bottom water spreads from its region of sinking, it eventually mixes with the warmer and more saline water above to form AABW. Along

480-427: A release of built-up stresses, the rift branched several times. Using data from ESA's Sentinel-1 satellites, we can see that there are multiple rift tips now within 5 km (3.10 miles) of the ice edge. We expect that these rifts will lead to the formation of several smaller icebergs." On 12 July 2017, Project MIDAS announced that a large, 5,800-square-kilometre (2,200 sq mi) portion of Larsen C had broken from

540-560: A sharp change in slope. The outflow of WSBW is influenced greatly by the Scotia Ridge . The movement of WBSW is listed as 16 Sv which contributes to a total 97 Sv outflow of AABW. 2 to 5 Sv of this production is newly formed bottom water off the Antarctic coast. The Weddell Sea is characterized by a cyclonic gyre bounded on the south by the Antarctic continent , on the west by

600-509: A study of the variability of bottom water temperature relative to El Niño-Southern Oscillation (ENSO), Southern Annular Mode (SAM), and Antarctic Dipole (ADP). This study was conducted to discover the impact WSBW has on the global climate. An 8-year time study of the potential temperature of the Weddell Gyre outflow was analyzed. Interannual variability was discovered in the winters of 1999 and 2002. The anomalies suggest ENSO influence with

660-745: Is a long ice shelf in the northwest part of the Weddell Sea , extending along the east coast of the Antarctic Peninsula from Cape Longing to Smith Peninsula . It is named after Captain Carl Anton Larsen , the master of the Norwegian whaling vessel Jason , who sailed along the ice front as far as 68°10' South during December 1893. In finer detail, the Larsen Ice Shelf is a series of shelves that occupy (or occupied) distinct embayments along

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720-547: Is around 2.8 million square kilometres (1.1 × 10 ^  sq mi). Various ice shelves, including the Filchner-Ronne Ice Shelf, fringe the Weddell sea. Some of the ice shelves on the east side of the Antarctic Peninsula , which formerly covered roughly 10,000 square kilometres (3,900 sq mi) of the Weddell Sea, had completely disappeared by 2002. The Weddell Sea has been deemed by scientists to have

780-715: Is the King Haakon VII Sea . Much of the southern part of the sea is covered by a permanent, massive ice shelf field, the Filchner-Ronne Ice Shelf . The sea is contained within the two overlapping Antarctic territorial claims of Argentine Antarctica , the British Antarctic Territory , and also resides partially within the Antarctic Chilean Territory . At its widest the sea is around 2,000 kilometres (1,200 mi) across, and its area

840-575: 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 volcanic Paulet Island . Around 1997, the northernmost emperor 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. In 2021, sponges and other unidentified suspension feeders were reported to have been found growing under

900-427: The Antarctic Peninsula , on the north by the Scotia Ridge , and extending as far east as 20 to 30°E. The precursor to bottom water formation is derived from the broad continental shelf west of 40°W where brine released during sea-ice formation produces a large reservoir of cold (0 to - 1.8 °C), high salinity (S ≥ 34.62  psu ) shelf water. This water mass then mixes with a modified form of Warm Deep Water near

960-683: The Filchner-Ronne Ice Shelf on a boulder at a depth of 1,233 m (872 of which were ice), 260 km from open water. In February 2021 the Alfred Wegener Institute for Polar and Marine Research with RV Polarstern , a colony of approximately 60 million Jonah's icefish was found to inhabit an area in the Weddell Sea. It is estimated that the colony covers around 240 square kilometers, with an average of one nest per every three square meters. Notes Bibliography 75°S 45°W  /  75°S 45°W  / -75; -45 Larsen Ice Shelf The Larsen Ice Shelf

1020-569: The ice floes . The sea is named after the Scottish sailor James Weddell (1787-1834), who entered the sea in 1823 and originally named it after King George IV ; it was renamed in Weddell's honour in 1900. Also in 1823, the American sealing captain Benjamin Morrell claimed to have seen land some 10–12° east of the sea's actual eastern boundary. He called this New South Greenland , but its existence

1080-522: The Larsen B sector partially collapsed and parts broke up, 3,250 km (1,250 sq mi) of ice 220 m (720 ft) thick, an area comparable to the US state of Rhode Island . In 2015, a study concluded that the remaining Larsen B ice-shelf would disintegrate by 2020, based on observations of faster flow and rapid thinning of glaciers in the area. Larsen B was stable for at least 10,000 years, essentially

1140-478: The Larsen C shelf broke away in July 2017 to form an iceberg known as A-68 . The ice shelf originally covered an area of 85,000 square kilometres (33,000 sq mi), but following the disintegration in the north and the break away of iceberg A-17 , it now covers an area of 67,000 square kilometres (26,000 sq mi). The collapse of Larsen B has revealed a thriving chemotrophic ecosystem 800 m (half

1200-477: 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. Otto Nordenskiöld , leader of the 1901–1904 Swedish Antarctic Expedition , spent a winter at Snow Hill with a team of four men when the relief ship became beset in ice and

1260-515: The Project MIDAS researchers on their site: "In another sign that the iceberg calving is imminent, the soon-to-be-iceberg part of Larsen C ice shelf has tripled in speed to more than 10 meters per day between 24 and 27 June 2017. The iceberg remains attached to the ice shelf, but its outer end is moving at the highest speed ever recorded on this ice shelf." On 7 July the Project MIDAS blog report stated: "The latest data from 6th July reveal that, in

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1320-604: The Scotia Ridge-Cape Norvegia section, potential temperature values at depths greater than 4,500 m (14,800 ft) range from -0.94 to -0.63 °C, while salinity values range from 34.639 to 34.652  psu . The northern limit of the core of Weddell Sea Bottom Water lies against the southern edge of the Scotia Ridge, suggesting that the circulation and property distributions are strongly influenced by bathymetry . The transport of Weddell Sea Bottom Water out of

1380-470: The WSBW as it does not have as much access to the cold, dense surface water. Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre . Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula . The easternmost point is Cape Norvegia at Princess Martha Coast , Queen Maud Land . To the east of Cape Norvegia

1440-449: The WSBW. With a strong ENSO event, sea ice is greatly reduced during the summer which exposes more surface water to the wind allowing it sink. This makes the WSBW colder than normal allowing it to inject colder water into much of the world's oceans. If the ENSO even is weak enough, the surface winds off the Antarctic coast can shift direction which creates a reduction in shelf water. This will warm

1500-534: The Weddell Sea part of the basin escaped compressional tectonics and remained an oceanic basin. The Weddell Sea is one of few locations in the World Ocean where deep and bottom water masses are formed to contribute to the global thermohaline circulation which has been warming slowly over the last decade. The characteristics of exported water masses result from complex interactions between surface forcing, significantly modified by sea ice processes, ocean dynamics at

1560-405: The Weddell Sea represents the outflow of newly formed bottom water plus entrained bottom water that enters the Weddell Sea from the southeast. Carmack and Foster estimated the production rate of bottom water from the mixing ratio of newly formed bottom water to entrained bottom water. Bottom water formation models based on hydrographic observations suggested that the bottom water formed at the edge of

1620-424: The clearest water of any sea. Researchers from the Alfred Wegener Institute , on finding a Secchi disc visible at a depth of 80 metres (260 ft) on 13 October 1986 , ascertained that the clarity corresponded to that of distilled water. In his 1950 book The 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,

1680-401: The coast. From north to south, the segments are called Larsen A (the smallest), Larsen B, and Larsen C (the largest) by researchers who work in the area. Further south, Larsen D and the much smaller Larsen E, F and G are also named. The breakup of the ice shelf since the mid-1990s has been widely reported, with the collapse of Larsen B in 2002 being particularly dramatic. A large section of

1740-447: The continental shelf break, and slope and sub-ice shelf water mass transformation. 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 the Weddell 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

1800-404: The continental shelf has an initial temperature of -1.4 to -1.2 °C. This range also represents the coldest bottom water observed at the base of the continental slope in the northwestern corner of the Weddell Sea. The fraction of newly formed bottom water in the outflowing WSBW ranges from about 12 to 31%, so the flow of newly formed bottom water out of the Weddell Sea is about 2 to 5 Sv. On

1860-552: The crack lengthened 18 km (11 mi) from 25 May to 31 May, and that less than 13 km (8 mi) of ice is all that prevents the birth of an enormous iceberg. "The rift tip appears also to have turned significantly towards the ice front, indicating that the time of calving is probably very close," Adrian Luckman and Martin O'Leary wrote on Wednesday in a blog post for the Impact of Melt on Ice Shelf Dynamics and Stability project, or MIDAS. "There appears to be very little to prevent

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1920-431: 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

1980-601: The ecosystem. The area had been protected by the overlying ice shelf from debris and sediment which was seen to be building up on the white microbial mats after the breakup of the ice shelf. Clams were observed clustered about the vents. The former Larsen A region, which was the farthest north and was just outside the Antarctic Circle , had previously broken up in the middle of the present interglacial and reformed only about 4,000 years ago. The former Larsen B, by contrast, had been stable for at least 10,000 years. The ice of

2040-411: The edge of the continental shelf to form a dense layer of bottom water, which in turn sinks along the continental slope and flows cyclonically around the western and northern perimeter of the Weddell Sea basin. Because large quantities of the high salinity water are observed on the continental shelf even during summer, bottom water may form throughout the year. Weddell Sea Bottom Water exhibits two forms:

2100-412: The entire Holocene period since the last glacial period. By contrast, Larsen A was absent for a significant part of that period, reforming about 4,000 years ago. Despite its great age, the Larsen B was clearly in trouble at the time of the collapse. With warm currents eating away the underside of the shelf, it had become a "hotspot of global warming". It broke over a period of three weeks or less, with

2160-414: The following decade. The breakaway process for the iceberg had begun by mid-2016. On 10 November 2016 scientists photographed the growing rift running along the Larsen C ice shelf, showing it running about 110 kilometres (68 mi) long with a width of more than 91 m (299 ft), and a depth of 500 m (1,600 ft). By December 2016, the rift had extended another 21 km (13 mi) to

2220-520: 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. The Weddell Sea is abundant with whales and seals. Characteristic fauna of the sea include the Weddell seal and killer whales , humpback whales , minke whales , leopard seals , and crabeater seals are frequently seen during Weddell Sea voyages. The Adélie penguin

2280-401: The gyre circulation was assumed to be driven by Sverdrup 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

2340-446: The huge icebergs that are often seen here. Snowhill Island, located east of the Antarctic Peninsula is almost completely snow-capped, hence its name. The Swedish Antarctic Expedition under Otto Nordenskiöld built a cabin on the island in 1902, where Nordenskiöld and three members of the expedition had to spend two winters. In 1915, Ernest Shackleton 's ship, Endurance , got trapped and was crushed by ice in this sea. After 15 months on

2400-448: The ice shelf. If all the ice that the Larsen C shelf currently holds back were to enter the sea, global waters would rise by an estimated 10 cm (4 in). The Larsen D Ice Shelf is between Smith Peninsula in the south and Gipps Ice Rise . It is considered to be generally stable. Over roughly the past fifty years it has advanced (expanded) whereas comparable George VI , Bach , Stange , and Larsen C ice shelves have retreated (to

2460-424: The iceberg from breaking away completely." The larger swath of the Larsen C ice shelf that sat behind the calved iceberg "will be less stable than it was prior to the rift" and may rapidly disintegrate in the same manner as Larsen B did in 2002. In June 2017 the speed of the imminent Larsen C iceberg accelerated, with the eastern end moving at 10 metres (33 ft) per day away from the main shelf. As discussed by

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2520-550: The late 1940s. According to a paper published in Journal of Climate in 2006, the peninsula at Faraday station warmed by 2.94˚C (5.3˚F) from 1951 to 2004, much faster than Antarctica as a whole and faster than the global trend; anthropogenic global warming causes this localized warming through a strengthening of the winds circling the Antarctic. The Larsen A ice shelf disintegrated in January 1995. From 31 January 2002 to March 2002

2580-501: The lower 2 km of the world ocean as Antarctic Bottom Water. It is proposed that the more saline, lower-oxygen WSBW is derived from shelf water descending into the deep ocean in the southwest Weddell Sea. The higher salinity of this WSBW is due to injection of high-salinity shelf water characteristic of the region. Fahrbach et al. propose that low-salinity bottom water is formed near the Larsen Ice Shelf . McKee et al., conducted

2640-462: The main ice shelf at some point between 10 and 12 July. The iceberg, designated A-68 , weighs more than a trillion tons and is more than 200 m (700 ft) thick. Project MIDAS updated their blog information on 19 July 2017 regarding Larsen C by revealing that a possible new rift appeared to be extending northwards from the point where A-68 had broken off in mid-July. The project researchers felt this questionable new rift might turn towards

2700-402: The most treacherous and dismal region on Earth. The Ross Sea is relatively peaceful, predictable, and safe." He continues for an entire chapter, relating myths of the green-haired merman 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 as Ernest Shackleton 's Endurance , at the mercy of

2760-799: The onset of the Andean orogeny in the Jurassic extensional tectonics created the Rocas Verdes Basin , a back-arc basin whose surviving southeastward extension forms the Weddell Sea. In the Late Cretaceous the tectonic regime of Rocas Verdes Basin changed leading to its transformation into a compressional foreland basin – the Magallanes Basin – in the Cenozoic . While this happened in South America

2820-427: The other hand, the much larger production rates sometimes proposed are probably estimates of the total transport of bottom water out of the Weddell Sea that include a large fraction of Antarctic Bottom Water entering the Weddell Sea from the southeast. The low-salinity, better ventilated forms of WSDW and WSBW flowing along the outer rim of the Weddell Gyre have the position and depth range that would lead to overflow of

2880-476: The overall ice-sheet mass balance in Antarctica is increasingly negative. The Larsen disintegration events were unusual by past standards. Typically, ice shelves lose mass by iceberg calving and by melting at their upper and lower surfaces. The disintegration events were linked by The Independent newspaper in 2005 to ongoing climate warming in the Antarctic Peninsula , about 0.5˚C (0.9˚F) per decade since

2940-512: The pack-ice Shackleton and his men managed to reach Elephant Island and safely returned home. In March 2022, it was announced that the well-preserved wreck of the Endurance had been discovered four miles (6.4 km) from its anticipated location, at a depth of 3,008 metres (9,869 ft). As with other neighboring parts of Antarctica, the Weddell Sea shares a common geological history with southernmost South America . In southern Patagonia at

3000-509: The point where only 20 km (12 mi) of unbroken ice remained and calving was considered to be a certainty in 2017. This was predicted to cause the calving of between nine and twelve percent of the ice shelf, 6,000 km (2,300 sq mi), an area greater than the US state of Delaware , or twice the size of Luxembourg . The calved fragment was predicted to be 350 m (1,150 ft) thick and to have an area of about 5,000 km (1,900 sq mi). The resulting iceberg

3060-601: The remainder of the World Ocean. The Weddell Gyre is a cold, low salinity surface layer separated by a thin, weak pycnocline from a thick layer of relatively warm and salty water referred to as Weddell Deep Water (WDW), and a cold bottom layer. 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

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3120-424: The shelf edge, compounding the risk that it would "continue on to Bawden ice rise" which is considered "a crucial point of stabilization for Larsen C Ice Shelf." As is true of all floating ice shelves, A68's departure from Antarctica had no immediate effect on global sea levels . However, a number of glaciers discharge onto the shelf from the land behind it, and they may now flow faster due to reduced support from

3180-404: The shelf is renewed on a much shorter time-scale and the oldest ice on the current shelf dates from only two hundred years ago. The speed of Crane Glacier increased threefold after the collapse of the Larsen B, likely due to the removal of a buttressing effect of the ice shelf. Data collected in 2007 by an international team of investigators through satellite-based radar measurements suggests that

3240-519: 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. Strong surface winds directed equatorward along

3300-508: The topographic confines of the Weddell Basin, whereas the more saline forms may be forced to recirculate within the Weddell Gyre are carried by the western boundary current of the Weddell Sea into the northwest corner of the Weddell Gyre. From there, these water masses flow eastward, either within the northern limb of the Weddell Gyre or reaching northward into the Scotia Sea, eventually cooling

3360-514: The volume transports associated with this western boundary region, or to the determination of deep convective circulation along the western boundary. 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

3420-489: Was crushed. The crew managed to reach Paulet Island where they wintered in a primitive hut. Nordenskiöld and the others were eventually picked up by the Argentine Navy at Hope Bay . All but one survived the ordeal. The Antarctic Sound is named after the expedition ship of Otto Nordenskiöld. The sound that separates the tip of the Antarctic Peninsula from Dundee Island is also referred to as "Iceberg Alley", because of

3480-432: Was disproved when the sea was more fully explored in the early 20th century. Weddell got as far south as 74°S ; the furthest southern penetration since Weddell but before the modern era was made by William Speirs Bruce in 1903. The Weddell Sea is an important area of deep water mass formation through cabbeling , the main driving force of the thermohaline circulation . Deepwater masses are also formed through cabbeling in

3540-445: Was predicted to be among the largest icebergs ever recorded , unless it would break into multiple pieces. On 1 May 2017 members of MIDAS reported that satellite images showed a new crack, around 15 km (9 mi) long, branching off the main crack approximately 10 km (6 mi) behind the previous tip, heading toward the ice front. Scientists with Swansea University in the UK say

3600-412: Was the fourth largest ice shelf in Antarctica, with an area of about 44,200 km (17,100 sq mi). Satellite radar altimeter measurements show that between 1992 and 2001, the Larsen Ice Shelf thinned by up to 0.27 ± 0.11 meters per year. In 2004, a report concluded that although the remaining Larsen C region appeared to be relatively stable, continued warming could lead to its breakup within

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