Sea ice in the Ross Sea
Seas of Antarctica, with the Ross Sea in the bottom-left
|Primary outflows||Southern Ocean|
The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Ross who visited this area in 1841. To the west of the sea lies Ross Island and Victoria Land, to the east Roosevelt Island and Edward VII Peninsula in Marie Byrd Land, while the southernmost part is covered by the Ross Ice Shelf, and is about 200 miles (320 km) from the South Pole. Its boundaries and area have been defined by the New Zealand National Institute of Water and Atmospheric Research as having an area of 637,000 square kilometres (246,000 sq mi).
The circulation of the Ross Sea is dominated by a wind-driven ocean gyre and the flow is strongly influenced by three submarine ridges that run from southwest to northeast[ citation needed ]. The circumpolar deep water current is a relatively warm, salty and nutrient-rich water mass that flows onto the continental shelf at certain locations. The Ross Sea is covered with ice for most of the year[ citation needed ].
The nutrient-laden water supports an abundance of plankton and this encourages a rich marine fauna. At least ten mammal species, six bird species and 95 fish species are found here, as well as many invertebrates, and the sea remains relatively unaffected by human activities. New Zealand has claimed that the sea comes under its jurisdiction as part of the Ross Dependency. Marine biologists consider the sea to have a high level of biological diversity and it is the site of much scientific research. It is also the focus of some environmentalist groups who have campaigned to have the area proclaimed as a world marine reserve. In 2016 an international agreement established the region as a marine park.
The Ross Sea was discovered by the Ross expedition in 1841. In the west of the Ross Sea is Ross Island with the Mt. Erebus volcano, in the east Roosevelt Island. The southern part is covered by the Ross Ice Shelf.Roald Amundsen started his South Pole expedition in 1911 from the Bay of Whales, which was located at the shelf. In the west of the Ross sea, McMurdo Sound is a port that is usually free of ice during the summer. The southernmost part of the Ross Sea is Gould Coast, which is approximately two hundred miles from the geographic South Pole.
The Ross Sea (and Ross Ice Shelf) overlies a deep continental shelf. Although the average depth of the world's continental shelves (at the shelf break joining the continental slope) is about 130 meters,the Ross shelf average depth is about 500 meters. It is shallower in the western Ross Sea (east longitudes) than the east (west longitudes). This over-deepened condition is due to cycles of erosion and deposition of sediments from expanding and contracting ice sheets overriding the shelf during Oligocene and later time, and is also found on other locations around Antarctica. Erosion was more focused on the inner parts of the shelf while deposition of sediment dominated the outer shelf, making the inner shelf deeper than the outer.
Seismic studies in the latter half of the twentieth century defined the major features of the geology of the Ross Sea.The deepest or basement rocks, are faulted into four major north trending graben systems, which are basins for sedimentary fill. These basins include the Northern and Victoria Land Basin in the west, the Central Trough, and the Eastern Basin, which has approximately the same width as the other three. The Coulman High separates the Victoria Land Basin and Central Trough and the Central High separates the Central Trough and Eastern Basin. The majority of the faulting and accompanying graben formation along with crustal extension occurred during the rifting away of the Zealandia microcontinent from Antarctica in Gondwana during Cretaceous time. Paleogene and Neogene -age and faulting and extension is restricted to the Victoria Land Basin and Northern Basin.
Basement grabens are filled with rift sediments of uncertain character and age.A widespread unconformity has cut into the basement and sedimentary fill of the large basins. Above this major unconformity (named RSU-6 ) are a series of glacial marine sedimentary units deposited during multiple advances and retreats of the Antarctic Ice Sheet across the sea floor of the Ross Sea during the Oligocene and later.
Drill holes have recovered cores of rock from the western edges of the sea. The most ambitious recent efforts are the Cape Roberts Project (CRP) and the ANDRILL project.Deep Sea Drilling Project (DSDP) Leg 28 completed several holes (270-273) farther from land in the central and western portions of the sea. These resulted in defining a stratigraphy for most of the older glacial sequences, which comprise Oligocene and younger sediments. The Ross Sea-wide major unconformity RSU-6 has been proposed to mark a global climate event and the first appearance of the Antarctic Ice Sheet in the Oligocene.
During 2018, Expedition 374 of the International Ocean Discovery Program (IODP), the latest successor to the DSDP, drilled additional holes (U1521-1525) in the central Ross Sea for determining Neogene and Quaternary ice sheet history.
The nature of the basement rocks and the fill within the grabens are known in few locations. Basement rocks have been sampled at DSDP Leg 28 drill site 270 where metamorphic rocks of unknown age were recovered,and in the eastern Ross Sea where a bottom dredge was collected. In both these locations the metamorphic rocks are mylonites deformed in the Cretaceous suggesting extreme stretching of the Ross Embayment during that time.
Marie Byrd Land - Rocks exposed in western Marie Byrd Land on the Edward VII Peninsula and within the Ford Ranges are candidates for basement in the eastern Ross Sea.The oldest rocks are Permian sediments of the Swanson Formation, which is slightly metamorphosed. The Ford granodiorite of Devonian age intrudes these sediments. Cretaceous Byrd Coast granite in turn intrudes the older rocks. The Byrd Coast and older formations have been cut by basalt dikes. Scattered through the Ford Ranges and Fosdick Mountains are late Cenozoic volcanic rocks that are not found to the west on Edward VII Peninsula. Metamorphic rocks, migmatites, are found in the Fosdick Mountains and Alexandra Mountains. These were metamorphosed and deformed in the Cretaceous.
The Ross Supergroup system and Beacon Supergroup - Ross System rocks exposed in Victoria Land and in the Transantarctic Mountains on the western side of the Ross Seaare possible basement rock below the sedimentary cover of the sea floor. The rocks are of upper Precambrian to lower Paleozoic in age, deformed in many places during the Ross Orogeny in the Cambrian. These miogeosyncline metasedimentary rocks are partly composed of calcium carbonate, often including limestone. Groups within the Ross System include the Robertson Bay Group, Priestley Group, Skelton Group, Beardmore Group, Byrd Group, Queen Maud Group, and Koettlitz Group. The Robertson Bay Group compares closely with other Ross System members. The Priestley Group rocks are similar to those of the Robertson Bay Group and include dark slates, argillites, siltstones, fine sandstones and limestones. They can be found near the Priestley and Campbell glaciers. For thirty miles along the lower Skelton Glacier are the calcareous greywackes and argillites of the Skelton Group. The region between the lower Beardmore Glacier and the lower Shackelton Glacier sits the Beardmore Group. North of the Nimrod Glacier are four block faulted ranges that make up the Byrd Group. The contents of the Queen Maud Group area are mainly post-tectonic granite.
Beacon Sandstone of Devonian-Triassic ageand the Ferarr volcanic rocks of Jurassic age are separated from the Ross Supergroup by the Kukri Peneplain. Beacon rocks are reported to have been recovered in the drill cores of the Cape Roberts Project at the western edge of the Ross Sea.
The Ross Sea circulation, dominated by polynya processes, is in general very slow-moving. Circumpolar Deep Water (CDW) is a relatively warm, salty and nutrient-rich water mass that flows onto the continental shelf at certain locations in the Ross Sea. Through heat flux, this water mass moderates the ice cover. The near-surface water also provides a warm environment for some animals and nutrients to excite primary production. CDW transport onto the shelf is known to be persistent and periodic, and is thought to occur at specific locations influenced by bottom topography. The circulation of the Ross Sea is dominated by a wind-driven gyre. The flow is strongly influenced by three submarine ridges that run from southwest to northeast. Flow over the shelf below the surface layer consists of two anticyclonic gyres connected by a central cyclonic flow. The flow is considerable in spring and winter, due to influencing tides. The Ross Sea is covered with ice for much of the year and ice concentrations and in the south-central region little melting occurs. Ice concentrations in the Ross Sea are influenced by winds with ice remaining in the western region throughout the austral spring and generally melting in January due to local heating. This leads to extremely strong stratification and shallow mixed layers in the western Ross Sea.
The Ross Sea is one of the last stretches of seas on Earth that remains relatively unaffected by human activities.Because of this, it remains almost totally free from pollution and the introduction of invasive species. Consequently, the Ross Sea has become a focus of numerous environmentalist groups who have campaigned to make the area a world marine reserve, citing the rare opportunity to protect the Ross Sea from a growing number of threats and destruction. The Ross Sea is regarded by marine biologists as having a very high biological diversity and as such has a long history of human exploration and scientific research, with some datasets going back over 150 years.
The Ross Sea is home to at least 10 mammal species, half a dozen species of birds, 95 species of fish, and over 1,000 invertebrate species. Some species of birds that nest in and near the Ross Sea include the Adélie penguin, emperor penguin, Antarctic petrel, snow petrel, and south polar skua. Marine mammals in the Ross Sea include the Antarctic minke whale, killer whale, Weddell seal, crabeater seal, and leopard seal. Antarctic toothfish, Antarctic silverfish, Antarctic krill, and crystal krill also swim in the cold Antarctic water of the Ross Sea.
The flora and fauna are considered similar to other southern Antarctic marine regions. Particularly in Summer, the nutrient-rich sea water supports an abundant planktonic life in turn providing food for larger species, such as fish, seals, whales, and sea- and shore-birds.
Albatrosses rely on wind to travel and cannot get airborne in a calm. The westerlies do not extend as far south as the ice edge and therefore albatrosses do not travel often to the ice-pack. An albatross would be trapped on an ice floe for many days if it landed in the calm.
The coastal parts of the sea contain a number of rookeries of Adélie and Emperor penguins, which have been observed at a number of places around the Ross Sea, both towards the coast and outwards in open sea.
A 10-metre (32.8 feet) long colossal squid weighing 495 kilograms (1,091 lb) was captured in the Ross Sea on February 22, 2007.
In 2010, the Ross Sea Antarctic toothfish fishery was independently certified by the Marine Stewardship Council, [ citation needed ]. However, a 2008 document submitted to the CCAMLR reported significant declines in toothfish populations of McMurdo Sound coinciding with the development of the industrial toothfishing industry since 1996, and other reports have noted a coincident decrease in the number of orcas. The report recommended a full moratorium on fishing over the Ross shelf. In October 2012, Philippa Ross, James Ross' great, great, great granddaughter, voiced her opposition to fishing in the area.and has been rated as a 'Good Alternative' by the Monterey Bay Aquarium Seafood Watch program
In the southern winter of 2017 New Zealand scientists discovered the breeding ground of the Antarctic toothfish in the northern Ross Sea seamounts for the first timeunderscoring how little is known about the species.
Beginning in 2005, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) commissioned scientific analysis and planning for Marine Protected Areas (MPA) in the Antarctic. In 2010, the CCAMLR endorsed their Scientific Committee's proposal to develop Antarctic MPAs for conservation purposes. The US State Department submitted a proposal for a Ross Sea MPA at the September 2012 meeting of the CCAMLR.At this stage, a sustained campaign by various international and national NGOs commenced to accelerate the process.
In July 2013, the CCAMLR held a meeting in Bremerhaven in Germany, to decide whether to turn the Ross Sea into an MPA. The deal failed due to Russia voting against it, citing uncertainty about whether the commission had the authority to establish a marine protected area.
In October 2014, the MPA proposal was again defeated at the CCAMLR by votes against from China and Russia.At the October 2015 meeting a revised MPA proposal from the US and New Zealand was expanded with the assistance of China, who however shifted the MPA's priorities from conservation by allowing commercial fishing. The proposal was again blocked by Russia.
On 28 October 2016, at its annual meeting in Hobart, a Ross Sea marine park was finally declared by the CCAMLR, under an agreement signed by 24 countries and the European Union. It protected over 1.5 million square kilometres of sea, and was the world's largest protected area at the time. However, a sunset provision of 35 years was inserted as part of negotiations, which means it does not meet the International Union for Conservation of Nature definition of a marine protected area, which requires it to be permanent.
The Bay of Whales is featured as the location for the landing point and base camp of an all-female explorer team in Ursula K. LeGuin's short story Sur. In the story, the women are the first people to reach the south pole, but keep their achievement a secret in order to save Amundsen from embarrassment.
The Antarctic toothfish is a species of notothen native to the Southern Ocean. It is often mistakenly referred to as an Antarctic cod, consistent with the misnaming of other notothenioid Antarctic fish as rock cods. However, notothenioid fishes are not closely related to cods, which are in another taxonomic order, the Gadiformes. The generic name Dissostichus is from the Greek dissos (twofold) and stichus (line) and refers to the presence of two long lateral lines, which are very important to the species’ ecology. The common name "toothfish" refers to the presence of biserial dentition in the upper jaw, thought to give it a shark-like appearance. The habitat of the Antarctic toothfish is in subzero degree water below latitude 60°S.
The Amundsen Sea, an arm of the Southern Ocean off Marie Byrd Land in western Antarctica, lies between Cape Flying Fish to the east and Cape Dart on Siple Island to the west. Cape Flying Fish marks the boundary between the Amundsen Sea and the Bellingshausen Sea. West of Cape Dart there is no named marginal sea of the Southern Ocean between the Amundsen and Ross Seas. The Norwegian expedition of 1928–1929 under Captain Nils Larsen named the body of water for the Norwegian polar explorer Roald Amundsen while exploring this area in February 1929.
The McMurdo Dry Valleys are a row of largely snow-free valleys in Antarctica, located within Victoria Land west of McMurdo Sound. The Dry Valleys experience extremely low humidity and surrounding mountains prevent the flow of ice from nearby glaciers. The rocks here are granites and gneisses, and glacial tills dot this bedrock landscape, with loose gravel covering the ground.
The Transantarctic Mountains comprise a mountain range of uplifted rock in Antarctica which extend, with some interruptions, across the continent from Cape Adare in northern Victoria Land to Coats Land. These mountains divide East Antarctica and West Antarctica. They include a number of separately named mountain groups, which are often again subdivided into smaller ranges.
Marie Byrd Land is the portion of West Antarctica lying east of the Ross Ice Shelf and the Ross Sea and south of the Pacific Ocean, extending eastward approximately to a line between the head of the Ross Ice Shelf and Eights Coast. It stretches between 158°W and 103°24'W. The inclusion of the area between the Rockefeller Plateau and Eights Coast is based upon the leading role of the American Rear Admiral Richard E. Byrd in the exploration of this area. The name was originally applied by Admiral Byrd in 1929, in honor of his wife, to the northwestern part of the area, the part that was explored in that year.
Iceberg B-15 was the world's largest recorded iceberg. It measured around 295 kilometres (183 mi) long and 37 kilometres (23 mi) wide, with a surface area of 11,000 square kilometres (4,200 sq mi)—larger than the whole island of Jamaica. Calved from the Ross Ice Shelf of Antarctica in March 2000, Iceberg B-15 broke up into smaller icebergs, the largest of which was named Iceberg B-15A. In 2003, B-15A drifted away from Ross Island into the Ross Sea and headed north, eventually breaking up into several smaller icebergs in October 2005. As of 2018, a large piece of the original iceberg was steadily moving northward, located between the Falkland Islands and South Georgia Island.
West Antarctica, or Lesser Antarctica, one of the two major regions of Antarctica, is the part of that continent that lies within the Western Hemisphere, and includes the Antarctic Peninsula. It is separated from East Antarctica by the Transantarctic Mountains and is covered by the West Antarctic Ice Sheet. It lies between the Ross Sea, and the Weddell Sea. It may be considered a giant peninsula stretching from the South Pole towards the tip of South America.
Pine Island Glacier (PIG) is a large ice stream, and the fastest melting glacier in Antarctica, responsible for about 25% of Antarctica's ice loss. The glacier ice streams flow west-northwest along the south side of the Hudson Mountains into Pine Island Bay, Amundsen Sea, Antarctica. It was mapped by the United States Geological Survey (USGS) from surveys and United States Navy (USN) air photos, 1960–66, and named by the Advisory Committee on Antarctic Names (US-ACAN) in association with Pine Island Bay.
The Antarctic bottom water (AABW) is a type of water mass in the Southern Ocean surrounding Antarctica with temperatures ranging from −0.8 to 2 °C (35 °F), salinities from 34.6 to 34.7 psu. Being the densest water mass of the oceans, AABW is found to occupy the depth range below 4000 m of all ocean basins that have a connection to the Southern Ocean at that level.
The West Antarctic Rift System is a series of rift valleys lying between East and West Antarctica. It encompasses the Ross Embayment, the Ross Sea, the area under the Ross Ice Shelf and a part of Marie Byrd Land in West Antarctica, reaching to the base of the Antarctic Peninsula. It has an estimated length of 3000 km and a width of approximately 700 km. Its evolution is due to lithospheric thinning of an area of Antarctica that resulted in the demarcation of East and West Antarctica. The scale and evolution of the rift system has been compared to that of the Basin and Range Province of the western U.S.
Antarctica is Earth's southernmost continent. It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14,200,000 square kilometres, it is the fifth-largest continent and nearly twice the size of Australia. At 0.00008 people per square kilometre, it is by far the least densely populated continent. About 98% of Antarctica is covered by ice that averages 1.9 km in thickness, which extends to all but the northernmost reaches of the Antarctic Peninsula.
The Southern Ocean, also known as the Antarctic Ocean or the Austral Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. As such, it is regarded as the second-smallest of the five principal oceanic divisions: smaller than the Pacific, Atlantic, and Indian Oceans but larger than the Arctic Ocean. This oceanic zone is where cold, northward flowing waters from the Antarctic mix with warmer subantarctic waters.
Dissostichus, the toothfish, is a genus of notothen found in the Southern Hemisphere. Toothfishes are marketed in the United States as Chilean sea bass or less frequently as white cod. "Chilean sea bass" is a marketing name, coined in 1977 by Lee Lantz, a fish wholesaler who wanted a more attractive name for selling the Patagonian toothfish to Americans. In 1994, the U.S. Food and Drug Administration (FDA) accepted "Chilean sea bass" as an "alternative market name" for Patagonian toothfish. The toothfish was remarkably successful in the United States, Europe and Asia, and earned the nickname “white gold” within the market. Toothfishes are vital to the ecological structure of Southern Ocean ecosystems. For this reason, on 4 September a national day is dedicated to the toothfish in South Georgia.
Haskell Strait refers to the ocean passage in southern McMurdo Sound, running between Cape Armitage, Ross Island and Cape Spencer-Smith, White Island, Antarctica. Oceanographically, it separates McMurdo Sound from the ocean basin beneath the Ross Ice Shelf. The Strait itself is around 25 km wide and in places over 900 m deep. Currents of nearly half a knot have been measured in the Strait, although typical flows are lower. It is mostly covered by the ice of the McMurdo Ice Shelf and fast ice in southern McMurdo Sound. On rare occasions sea-ice breakout exposes the north-west corner of the Strait which becomes navigable and vessels can actually moor off Scott Base.
Christina Riesselman is an American paleoceanographer whose research focus is on Southern Ocean response to changing climate.
Christine Siddoway is an American Antarctic researcher, best known for her work on the geology and tectonics of the Ford Ranges in western Marie Byrd Land.
Mount Luyendyk is a summit in the western Fosdick Mountains of the Ford Ranges of Marie Byrd Land, West Antarctica. It forms a prominent exposure in the northwestern Iphigene massif. The peak is named in recognition of Bruce P. Luyendyk, professor (emeritus), University of California,Santa Barbara, who was active in ground- and ocean-based Antarctic research from 1989-2015, significantly advancing the scientific knowledge of the Ross Embayment region of Antarctica. Luyendyk led two on-land expeditions in the Ford Ranges, and was principal investigator for five marine geophysical expeditions in the Ross Sea.
Bruce Peter Luyendyk is an American geophysicist and oceanographer, currently professor emeritus of marine geophysics at the University of California, Santa Barbara. His work spans marine geology of the major ocean basins, the tectonics of southern California, marine hydrocarbon seeps, and the tectonics and paleoclimate of Antarctica. His research includes tectonic rotations of the California Transverse Ranges, participation in the discovery of deep-sea hydrothermal vents, quantitative studies of marine hydrocarbon seeps, and geologic exploration of the Ford Ranges in Marie Byrd Land, Antarctica.
Martin J. Siegert is a British glaciologist, a professor at Imperial College London, and co-director of the Grantham Institute - Climate Change and Environment.
The Ross Embayment is a large region of Antarctica, comprising the Ross Ice Shelf and the Ross Sea, that lies between East and West Antarctica.