For any understanding of this region of the Southern Ocean, some historical perspective is necessary. Perhaps the most comprehensive summary of Antarctic exploration prior to the Heroic Age is that of Mill (1905). Other works consulted include Murray (1886,1894), Greely (1929), Fleming (1952), Priestley (1956), Kir-wan (1959), Brodie (1965), Quartermain (1967), M. Deacon (1971), G.E.R. Deacon (1975a, 1977a, 1984), Lovering and Prescott (1979), Shapley (1985), Walton and Bonner (1985), Hatherton (1986), Mickleburgh (1987) and Walton (1987). A brief summary of exploratory expeditions until the IGY, including cruise tracks, is given by Dater (1975).
The term Antarctica is Greek (Antarktos — opposite the bear) and the idea of a southern landmass Greek. It was Aristotle who first proposed that the earth is a sphere and Eratosthenes (who incidentally has a seamount and abyssal plain off the Nile Delta named after him, Ross et al., 1978) who estimated the size of this sphere. The idea of a southern landmass was based on considerations of symmetry of landmasses with the earth divided into five zones, a northern frigid and a northern temperate zone separated from their southern counterparts by a torrid zone (an impassable gulf of unendurable heat). Although Phoenician sailors traded far into the tropics and had possibly circumnavigated Africa at this time, the belief persisted that the Southern Hemisphere of the globe contained habitable land which could never be reached.
From this time follows 1,500 years in which Greek learning passed to the Arab world and such ideas became the subject of abstruse theological debate in Christendom. It was not until the 15th century that the renaissance, with its revival of classical ideas and its great voyages of exploration, began in Europe. Of these voyages, the circumnavigation of the globe by Magellan (1519-22) in which he passed through the Magellan Straits and saw continuous land of continental appearance to the south is the most significant here. By the early 16th century, cartographers such as Leonardo da Vinci (1515) and Schöner (1515) were producing maps of the world based on these voyages of exploration. The map of Orontius (1531) combined the results of the previous two charts with Magellan's discovery and showed the huge southern continent of Terra Australis (Fig. 1.2). As Mill (1905) stated, "the vast Terra Australis was built entirely of conjecture, save for the Tierra del Fuegian scrap of fact, but was a continent indeed, although not yet fully known, the finding of which would repay any explorer, and place the happy discoverer on a pedestal beside Columbus and Vasco de Gama, perhaps even as high as Magellan himself."
In the middle of the 18th century, the southern continent figured upon all maps as the seat of a great continent awaiting discovery. The last of the firm believers in this idea was Alexander Dalrymple. Dalrymple has been described as an obdurate, cantankerous Scott, of some ability, much self-conceit and no sense of proportion. In his volume of 1770-71 "An historical collection of the several voyages and discoveries in the South Pacific Ocean", he suggested that the Southern Continent was larger "than the whole civilized part of Asia from Turkey to the eastern extremity of China" and that "the scraps from this table would be sufficient to maintain the power, dominion and sovereignty of Britain". However, Dalrymple's map of exploration of the Pacific shows that all voyages to that date had crossed the Pacific north of 30°S so that the area south of this latitude was entirely unknown to Europeans. Dalrymple was first nominated for the leadership of the astronomical expedition to study the transit of Venus in Tahiti in 1769 but quarrels over the overall command of the expedition led him to decline and the appointment was given instead to the man who was to become one of the greatest maritime explorers, James Cook.
It is not necessary here to describe Cook's first voyage of circumnavigation of 1768-71 in the Endeavour, from Cape Horn to Tahiti, the circumnavigation and charting of New Zealand, the journey up the coast of Australia and return via New Guinea and Java. Nonetheless, this voyage led Cook to the view that "to make new discoveries the Navigator must traverse or circumnavigate the globe in a higher parallel than has hitherto been done" so that the whole matter of a southern continent could then "be wholy clear'd up".
Cook's second voyage of 1772-75 resulted in the first crossing of the Pacific at high latitude. The Resolution left New Zealand on November 26 1773 (the Adventure having returned to England) and made 67°31'S at 135°W on December 22 before being forced to turn north to 47°50'S. On January 30 1 774, the ship made 71°10'S, 106°54'W, the furthest south of the 18th century, before returning to New Zealand via Easter Island. Following this voyage, Cook wrote "I will not say that it is impossible anywhere to get farther to the south; but attempting it would have been a dangerous and rash enterprise It was, indeed, my opinion, that this ice extended quite to the pole, or perhaps joined to some land to which it has been fixed from the earliest time". On November 101774, Cook again left New Zealand and reached Tierra del Fuego on December 17 on a course between 57°S and 53°S meeting little ice and no land. Cook's achievement was to dispose of the theory of the southern continent and, on his return, he wrote "should anyone possess the resolution and the fortitude to elucidate this point by pushing yet further south than I have done, I shall not envy him the fame of his discovery, but I make bold to declare that the world will derive no benefit from it". Cook's scientific programme has beem summarized by Rubin (1982a) and his observations of sea ice by Herd-man (1969).
On January 14 1775, Cook sighted South Georgia in the South Atlantic. Arriving in the height of summer in the middle of the breeding season, Cook and the naturalists aboard the Resolution marvelled at the huge concentrations of wildlife (whales, seals, penguins and seabirds) in the seas around the island (Mickleburgh, 1987). Such a wealth of wildlife was unexpected and helped to foster the myth of the high productivity of the South Ocean.
Following Cook's voyage, there was a long gap in Antarctic exploration as such but his description of the vast abundance of seals in South Georgia fell on attentive ears. In 1778, English sealers brought back from South Georgia and the Magellan Straits 40,000 seal skins and 2,800 tonnes of elephant seal oil. In 1801, the amount of oil imported from these regions reached 6,000 tonnes. The period of destruction of the Southern Ocean marine mammal stock had begun.
Although initial interest of the U.S. and British sealers centred on areas such as the South Shetlands and South Georgia in the South Atlantic, the nature of sealing led to a constant need to search for new grounds since the first to reach a new ground was sure of an immense booty whereas the late comer could go away empty handed (cf. Clark, 1884-87; Turbott, 1952; Bonner and Laws, 1964; Stonehouse, 1972; Bonner, 1982; Laws, 1984). By 1813, New Zealand and the sub-Antarctic islands in this region had been largely divested of their seal populations. The exploitive nature of sealing helped ensure its secrecy so that adequate records of sealing activity are in many cases lost. Nonetheless, some sealers took an interest in exploration and this applied to the Enderby Brothers of London.
In 1830-33, John Biscoe was sent on a sealing voyage by the Enderby Brothers and circumnavigated the Antarctic continent for 160 degrees of longitude south of 60°S aboard the brig Tula (150 tonnes) and cutter Lively (82 tonnes) (the third such circumnavigation, Savours, 1983). The Lively eventually foundered in the Falkland Islands after completing the circumnavigation and it is surprising that such a small vessel could make such a navigation even though conditions on board must have been wretched (Mill, 1905). In late 1831, Biscoe spent three-months sealing off New Zealand, the Chatham Islands and the Bounty Islands and in 1832 made his first landing in Antarctic territory, probably on An vers Island off the central stretch of the coast that he named Graham Land. After his return to England, Biscoe made several attempts to push exploration south of New Zealand but was always stopped by ice at about 63°S. In 1838, the Enderbys fitted out the 154 tonne schooner Eliza Scott with the 54 tonne cutter Sabrina under John Balleny. In February 1832, Balleny reached 69°S, 172°E in the Ross Sea before being stopped by ice and then landed on the Balleny Islands. This was the first time land had been seen in the Antarctic Circle south of New Zealand. Balleny returned to London in time to pass on his results to James Clark Ross. In 1847, the Enderbys obtained a concession from the British Government for a whaling station on the Auckland Islands. This is not the place for a full account of sealing and whaling activities in this region of the South Pacific which is dealt with more fully by Baker (this volume) but it does show that, for a time, these seamen played a leading role in the geographical exploration of these waters.
The next great voyage to concern us is Bellingshausen's circumnavigation of 1819-21. Bellingshausen left Sydney on November 11 1820 and arrived at Rio de Janiero on March 9 1821 via Macquarie Island where they experienced a submarine earthquake and met elephant seal hunters. Bellinghausen's track was immediately north of the ice and it is instructive to note that for the whole cruise Bellingshausen sailed over 242 degrees of longitude south of 60°S of which 41 degrees were within the Antarctic Circle, whereas Cook sailed only 125 degrees of longitude south of 60°S of which 24 degrees were within the Antarctic Circle. Bellingshausen also took care to cross all the great gaps left by Cook thus confirming the existence of a continuous open sea south of 60°S. He also discovered two islands which he named Peter I Island and Alexander Island off the west coast of the Antarctic Peninsula. Unfortunately, whilst Bellingshausen wrote a full account of his voyage, it was in Russian so that details of this expedition were not made available to subsequent expeditions until 1902. Bellingshausen's scientific programme has been summarized by Rubin (1982b).
We now come to the period 1838-43 when four expeditions, of D'Urville (France), Wilkes (U.S.A.), Balleny (Britain) and Ross (Britain), were engaged in Antarctic exploration. Of these, only the expedition of Ross (1839-43) need concern us here, although Walker in Flying Fish reached 70°S, 105°W and Ringgold in Porpoise 68°S, 95°44'W during the Wilkes expedition (Greely, 1929). The expedition of Ross was described by Murray (1894) as the greatest, most successful and most important expedition to the Antarctic to that date.
In the early 19th century, the study of magnetism had become a pressing problem with the beginning of a new era of maritime activity and Gauss had already predicted that the South Magnetic Pole would be located in the Antarctic at about 60°S, 146°E. The discovery of the South Magnetic Pole became the principal object of the British Antarctic expedition and in 1838 a meeting of the British Association in Newcastle urged the dispatch of an Antarctic expedition for magnetic measurements between Australia and Cape Horn. The man chosen as leader was Captain James Clark Ross, the discoverer of the North Magnetic Pole, who had very substantial experience in the Arctic (Ross, 1982).
The expedition was entirely naval and consisted of two ships H.M.S. Erebus (370 tonnes) and H.M.S. Terror (340 tonnes) which were specially strengthened for Antarctic work (Richardson and Gray, 1844-75). The first summer's voyage, leaving Campbell Island on December 17 1840, was easily the most successful. Because of their strengthening, the ships were able to penetrate the pack ice where every previous explorer would have had to turn back and on February 1 1841 reached 78°4'S, 173°20'W. Ross was able to land on Possession and Franklin Islands, only the second landings south of the Antarctic Circle (after D'Urville). He discovered and named the mountain chain of Victoria Land, the great volcanoes of Mounts Erebus and Terror and McMurdo Bay, and sailed over 500 km eastwards along the front of the great ice barrier, rising 45-60 m above sea level, that now bears his name (the Ross Ice Shelf). He was able to carry out soundings and dredging (recovering a rich haul of rock fragments dropped by icebergs and a profusion of animal life), take magnetic and meteorological observations, observe the marine life and approach within about 300 km of the South Magnetic Pole. Whales of great size were observed and Ross believed them to be a valuable species, although it was to be 50 years before whaling fleets visited the region. Within 2 km of the ice barrier, he obtained a depth of 480 m with a fine soft mud on the bottom. He also noted the low atmospheric pressure in the Southern Ocean. The success of this first season was rewarded by the award of the next Founder's Medal of the Royal Geographical Society.
In the second season, Ross made his southward approach 2,500 km to the east. On the way, much time was spent measuring the sea temperatures at great depths (but the results were invalid because the thermometers were not protected). In spite of making a latitude of 78°9'S at 161°27'W within 2.5 km of the barrier (the most southerly latitude of the 19th century), conditions were much more difficult than in the first season and the results more disappointing.
In the third season, attention was turned to the Weddell Sea and a latitude of 71°30'S was made in conditions much more difficult than encountered in the Ross Sea. The chief result of this was that, when the assault was finally made on the Pole, it was made from the Ross, and not the Weddell, Sea.
After this burst of activity, there follows a long gap in Antarctic exploration. In Britain, this was due to the search for Sir John Franklin who was lost (aboard Erebus and Terror) during the search for the North-West Passage in 1845, in the U.S.A. due to the intervention of the civil war (although Wilke's voyage had never been properly supported), and in Germany due to the Franco-Prussian war and the untimely death of Admiral Teggetthoff. The most important development of this period was the H.M.S. Challenger expedition of 1872-76 which resulted in the circumnavigation of the globe and observations south of 60°S between Kerguelen Island and Australia. The Challenger was powered by sail and steam but not ice strengthened. One of the principal scientists onboard was John (later Sir John) Murray. In this region, the ship carried out soundings and dredgings (Murray, 1894). The hauls contained a more abundant fauna than any others on the whole voyage and recovered glaciated rock fragments including granites, mica schists, grained quartzites, sandstones, limestones and shales which showed the conti nental nature of Antarctica. A permanent high-pressure zone over the Antarctic continent was also demonstrated. However, the deep-sea thermometers used were found to be inadequate at these latitudes.
During this period there were a number of leading spokesmen for Antarctic research. These included M.F. Maury, Superintendent of the United States Hydrographie Office, who introduced the idea of the great circle route for sailing ships which necessitated sailing from Australia to Cape Horn at high latitudes across the Pacific (Maury, 1963; Williams, 1963), Georg von Neumeyer, Director of the Deutsche Seewarte at Hamburg, whose interests were in magnetism, oceanography and meteorology, Sir John Murray of the Challenger expedition, and Sir Clements Markham, later President of the Royal Geographical Society. In this regard, particular mention must be made of Murray's two papers (1886, 1894) which brilliantly summarized the accumulated knowledge gained to that date. Murray (1894) was bold enough to deduce the nature of the Antarctic continent based on existing marine observations and to outline the requirements for a modern Antarctic expedition which would be "of capital importance to British science", although of dubious commercial prospects. He specifically did not advocate "a dash at the South Pole", although, in this, he was to be outmanoeuvred by Markham. In the discussion to Murray's (1894) paper, it was suggested that such an expedition could be justified as knowledge for its own sake and Sir William Flower (described as the greatest authority on marine mammals) noted that commercial exploitation of whales and seals in the region "must end in extermination in a very few years if they are to be killed in the way in which seals have been killed throughout the whole of the southern parts of the world."
The culmination of Victorian debate was the Sixth International Geographical Congress held in London in 1895 in which the resolution was passed "that the Congress record its opinion that the exploration of the Antarctic Regions is the greatest piece of geographical exploration still to be undertaken. That, in the view of the additions to knowledge in almost every branch of science which would result from such a scientific exploration, the Congress recommends that the scientific societies throughout the world should urge, in whatever way seems to them most effective, that this work should be undertaken before the close of the century".
The 19th century ended with the voyage of the Antarctic under Captain Kris-tensen to the Ross Sea in 1894-95 with C.E. Borchgrevink aboard; thus resulting in the first landing on the Antarctic continent at Cape Adare. In 1897-99, the Belgica under Gerlache carried out work off the west coast of the Antarctic Peninsula. It was beset for 12 months from March 1898 and drifted between 80°30'W and 102°W to a latitude of 71°32'S resulting in the first wintering over in Antarctica (Owen, 1941). In 1898-1900, Borchgrevink led an expedition on the Southern Cross in which a party of 10 wintered over at Cape Adare (the first party to do so voluntarily). A summary of this expedition (including the scientific results) is given by Borchgrevink (1900). By this time, seven non-existent islands had been charted in this region of the South Pacific and it took a number of years before all were expunged from navigational charts (Stommel, 1984).
The 20th century began with the assault on the Pole from the Ross Sea during the expeditions of Scott (1901-04, 1910-13), Shackleton (1907-09, 1914-17), Amundsen (1910-12) and Shirase (1911-12) (although Shirase abandoned his attempt from the Bay of Whales when he heard of the early start of Amundsen and Scott, Lovering and Prescott, 1979). This phase of Antarctic activity became known as the Heroic Age and is too well known to warrant discussion. Nonetheless, the scientific reports of the National Antarctic Expedition 1901-1904 and the British (Terra Nova) Antarctic Expedition 1910-1913 added greatly to the scientific knowledge of the Ross Sea region. Scott's first expedition also had a manual written for it summarizing Antarctic scientific methods and results (Murray, 1901). A précis of the oceanographic observations obtained during Scott's last expedition is given by Deacon (1975b) and of foraminiferal distributions by Ear-land (1935). A substantial account of the Ross Ice Shelf is given by Debenham (1948). Scott's expeditions were, of course, naval expeditions modelled on the search for Sir John Franklin's 1845-48 missing North-West Passage Expedition and the Arctic expedition of 1875-76 (Markham, 1986). This induced a conservatism in equipment and technique and these expeditions have been described as cumbersome, over-manned and inefficient (Markham, 1986). Nonetheless, in spite of Huntford's (1979) scathing account of Scott and his methods, it is evident that Scott's expeditions left by far the greatest scientific legacy of this period.
In 1903-05, Jean Charcot in the Français explored the west coast of the Antarctic Peninsula in the vicinity of the Biscoe Islands, and in 1908-10 explored the region again in the Pourquoi Pas?, the most modern comfortable polar vessel of its time, and wintered at Petmann Island. Scientific observations were made in the fields of meteorology, glaciology, geology and zoology. During 1915-16, the U.S. vessel Carnegie circumnavigated the Antarctic continent between 50°S and 60°S charting the earth's magnetic field (Stommel, 1984; Shapley, 1985). The ship took 118 days to circumnavigate the continent from Lyttelton, New Zealand, to its return. There was precipitation on 100 days and gales on 52, half of which reached hurricane force (Shapley, 1985).
The next phase of exploration had its origin in the First World War (1917) with the realization that the Southern Ocean whaling industry was important to the economy of Britain but that not enough was known about the habits of whales. Ultimately, this led to the Discovery II expeditions which can be said to put oceanographic studies in the Southern Ocean on a modern scientific basis. Studies undertaken were wide-ranging and included not only the biology of the whales but also the oceanography of the Southern Ocean and the distribution of the krill upon which the whales feed. The Discovery Reports which run to 37 volumes became a major reference and included such classic hydrological studies as Deacon (1937) and Mackintosh (1946). The concept of the Antarctic Convergence and Subtropical Convergence was first introduced and a chart showing their distribution around Antarctica compiled as a result of these voyages (Deacon, 1977a). Detailed studies of the Pacific Sector were undertaken during the Second Commission (1931-33) which included the fourth circumnavigation of Antarctica and the first in winter, the Third Commission (1933-35) which involved several long voyages through the Pacific, the Fourth Commission (1935-37) in which a circumpolar cruise was planned for the summer months but the ship had to be diverted to the Bay of Whales, Ross Sea, to rescue Lincoln Ellsworth, the Fifth Commission (1937-39) which involved circumnavigation in summer, and the Sixth Commission (1950-51) which involved oceanographic studies around New Zealand as well as a circum-Pacific crossing. Summaries of this work have been given by Herdman (1952), Coleman-Cooke (1963) and Hardy (1967). Some limited sediment sampling was carried out on the west coast of the Antarctic Peninsula during these voyages (Neaverson, 1934).
Whaling was indeed a major factor in the Southern Oceans in the inter-war years (Dawbin, 1952; Priestley, 1956; Quartermain, 1967; Laws, 1977; Stone-house, 1972; Allen, 1980; Sugden, 1982; Tonnessen and Johnsen, 1982; Brown and Lockyer, 1984; Baker, this volume) and a summary of political regulations governing whaling are listed in Coleman-Cooke (1963, Appendix E). Between 1923 and 1930, 6,111 whales yielding 526,238 barrels of oil were caught in the Ross Sea (Tennesson and Johnsen, 1982, Table 25). Between 1925 and 1929, pelagic whaling (i.e., based on factory ships rather than shore stations) resulted in a catch of 29,671 whales yielding 2,282,327 barrels of oil in the Antarctic region (Tonnessen and Johnsen, 1982, Table 24). Whaling continued after the war. The total catch of whales in the Antarctic in the period 1904-78 was 1,393,254 whales yielding 83,360,382 barrels (13.9 million tonnes) of oil (Tennesson and Johnsen, 1982, Table 67). Tonnessen and Johnsen (1982) give no figures for the Pacific sector alone but a chart published by Sugden (1982) shows that 163,000 whales were caught in the area between 130°E and 50°W (the Pacific Ocean sector) during the period 1931-76 whereas 679,200 whales were caught between 50°W and 130°E (the Atlantic and Indian Ocean sectors).
The inter-war phase of whaling activity was also significant in as much as it was the application by the Norwegian, C.A. Larsen, for a whaling concession in the Ross Sea that led to the setting up of the Ross Dependency in 1923 (Tennesson and Johnsen, 1982; Watt, 1989). Whilst British claims in this region stretched back to Ross's landing on Possession Island in 1841, Britain persuaded a reluctant New Zealand Government to take over administration of the Ross Dependency (stretching between 160°E and 150°W south of 60°S). It was not, however, until 1956 that New Zealand began its permanent scientific programme in the Ross Dependency (Quartermain, 1967). In the Antarctic Peninsula region, the competing claims of Chile (90°-53°W), Argentina (74°-25°W) and Britain (80°-20°W) (all south of 60°S) date from the Second World War period (cf. Lovering and Prescott, 1979).
The inter-war years also saw the use of aircraft and tractors in Antarctica by men such as Byrd and Ellsworth but this is beyond the scope of this chapter (cf. Shapley, 1985). Byrd's work was based on the Little America station in the Bay of Whales. Twelve sediment cores were collected in the Ross Sea (Stetson and Upson, 1937) and echo soundings taken (Roos, 1937) during the Byrd expedition. The U.S. Antarctic Service expedition of 1939-41 also established a permanent base, Little America III, in the Bay of Whales (Shapley, 1985). A key development of this period was the publication of Du Toit's classic book "Our Wandering Continents" (Du Toit, 1937) which recognized the vital role of Antarctica in the reconstruction of Gondwanaland (cf. Sutton, 1977; Craddock, 1978, 1982), a concept first proposed by J.D. Hooker in 1851 (Walton, 1987) and by E. Suess in 1885 (Teichert, 1952). The Norwegians circumnavigated the Antarctic continent in 1930-31 with the Norvegia and in 1933-34 with the Thorshavn, in both cases carrying out a scientific programme (Holtedahl, 1935).
Following the Second World War, the U.S. Navy mounted a military exercise, Operation High Jump, in 1945-47 (Editorial Committee, 1952; Shapley, 1985) which resulted in five bathythermograph sections across the Antarctic Convergence (Pritchard and LaFond, 1952) and the preparation of a sediment chart of the region (Hough, 1956; Thomas, 1959). The great depth of the Antarctic shelf break (420510 m) was also established during this expedition (Dietz, 1952). In 1954-55, the U.S.S. Atika undertook a cruise to the Ross Sea as a reconnaissance for the International Geophysical Year (U.S. Navy Hydrographie Office Tech. Rep. 48) and this was followed by the very extensive U.S. Navy and later Coastguard Programme, Operation Deep Freeze, lasting from 1956 to the present, which resulted in wide-ranging hydrological and geophysical studies in the region (cf. U.S. Navy Hydrographie Office Tech. Rep. 190; U.S. Navy Task Force 43,1969) (cf. Thomas, 1960). The earlier data (up to Operation Deep Freeze II) were compiled into an oceanographic atlas of the Southern Ocean (Anonymous, 1957; Lyman, 1958). The Norwegians also carried out numerous hydrological and biological stations in the region during the Brategg expedition of 1947-48 (Mosby, 1956) and a summary of oceanographic measurements taken from the Japanese whaling fleet from 1946-52 was presented by Hazawa and Tsuchida (1954). Substantial studies of bottom sediments and geomorphology were also carried out during the cruise of the Ob from 1955-58 (Kort, 1962; Lisitzin, 1962,1970; Zhivago, 1962; Maksimov, 1964). Whilst much information was available on the Pacific Sector of the Southern Ocean by the time of the IGY (particularly in physical oceanography and marine biology), much remained to be learned (Fleming, 1952; Ewing and Heezen, 1956; Deacon, 1963; Brodie, 1965; Angino and Lepley, 1966). This is well illustrated by Ewing and Heezen's review which emphasized the limited geological knowledge in the region (cf. Frakes, 1983). The Pacific-Antarctic Ridge, for instance, was poorly known and the Macquarie Ridge was subsequently shown to be an island arc (Cullen, 1967; Summerhayes, 1967), not a mid-ocean ridge as proposed by Ewing and Heezen.
The IGY of 1957-58 marks the beginning of the most recent phase of Antarctic activity in which scientific research has been pre-eminent. Many nations such as New Zealand mark their permanent occupation of the continent from that date.
Following the IGY, the Antarctic Treaty was ratified in 1961 by the 12 nations that participated in the IGY. There are now 22 nations with consultative status (i.e., have continuing scientific programmes in the region). The provisions of the Antarctic Treaty apply to the area south of 60°S latitude including all ice shelves, although the rights of passage on the high seas are maintained under international law. The principal result of the Antarctic Treaty is that the Antarctic continent has been a region of peaceful international scientific co-operation. Lovering and Prescott (1979) describe the treaty as one of the most successful treaties negotiated for international co-operation (cf. Laws, 1985a). An overview of advances in Antarctic geophysical sciences since the IGY is given in Antarctic Journal of the
United States 1986,21(2). A brief description of Antarctic activities until 1974-75 is given by Dater (1975).
In New Zealand, scientific studies in the southern sector of the Pacific were carried out from U.S. vessels as part of Operation Deep Freeze in 1958 (Garner, 1958) and from U.S.C.G.C. Glacier in 1964-65 (Hatherton et al., 1965; Forbes, 1966) as well as from H.M.N.Z.S. Pukaki and Hazvea in 1956-57 (Burling, 1961) and H.M.N.Z.S. Endeavour in 1957 (forming part of the Trans-Antarctic Expedition) (Cassie, 1963), in 1958-60 (Adams and Christoffel, 1962; Bullivant, 1967) and 1963-65 (Ross, 1967; Summerhayes, 1969; Christoffel and Falconer, 1972) (cf. Burling, 1960; Meade, 1978). Since that time, New Zealand's oceanographic programme in southern waters has been largely in abeyance except as part of international co-operative programmes (Gordon, 1977; Neal and Nowlin, 1979; Bryden and Heath, 1985), on ships of opportunity (Glasby et al., 1975; Davey et al., 1982) or through the ice (Gilmour, 1979; Carter et al., 1981). More recently, New Zealand has been involved in the MSSTS (McMurdo Sound Sediment and Tectonic Studies) (Barrett, 1986) and CIROS (Cenozoic Investigations in the Western Ross Sea) (Barrett and Scientific Staff, 1985; Barrett, 1987,1989) projects which involved drilling into the seafloor through sea ice. A bathymetric chart of McMurdo Sound is a by-product of this work (Pyne et al., 1985). Sedimentological studies have also been carried out in McMurdo Sound by sampling through the sea ice and from U.S.C.G.C. Glacier (Macpherson, 1987; Ward et al., 1987). Korsch and Wellman (1988) have reviewed the tectonic evolution of the region. Fraser (1986) has presented an excellent photographic survey of New Zealand's sub-antarctic islands (cf. Clark and Dingwall, 1985). Vincent (1988) has reviewed microbial ecosystems in the marginal-ice zone and open ocean around Antarctica. Summaries of New Zealand work in the Ross Sea have been given by Knox (1986) and Hatherton (in press).
In the U.S.A., the 1961 Monsoon expedition traversed the Pacific-Antarctic Ridge at 64°30'S, 173°E, analyzed rare gases in the South Pacific seawater (Craig et al., 1967; Craig, 1970) and collected manganese nodules from the Southern Ocean (Mero, 1965). Cruises 1-55 of the U.S.N.S. Eltanin (1962-72) studied the entire circumpolar region and represent perhaps the most significant advance in the study of all aspects of the Antarctic Sector of the Pacific (cf. Antarctic Research Series, vol. 15,1971; vol. 19,1972; Hayes and Pitman, 1972). Some of the earlier Eltanin data are excellently summarized in the maps of the Antarctic Map Folio Series. DSDP legs 28 (1972-73), 29 (1973), 35 (1974) and 90 (1983) were also a key development which played a major role in increasing our knowledge of the palaeoclimatology and palaeoceanography of the region (cf. Johnson et al., 1982). Since the early 1970s, the United States has relied mainly on work from icebreakers on transit from New Zealand to McMurdo Sound or within the Ross Sea (cf. Jacobs et al., 1981; Anderson et al., 1983, 1984b; Nelson and Smith, 1986; Wilson et al., 1986) or from specific cruises such as those of R.V. Knorr (1978-79) (Suess and Ungerer, 1981; Nelson and Gordon, 1982) or S.P. Lee (1984) (Eittreim, Cooper, and Scientific Staff, 1984; Cooper and Davey, 1987). In 1974, R .V.Melville went to almost 70°S southeast of New Zealand as part of the GEOSECS programme to study seawater chemistry (Broecker et al., 1982). In 1982-83,
U.S.C.G.C. Polar Star circumnavigated the Antarctic continent (Holm-Hansen and Chapman, 1983; Hanson and Erickson, 1985). The interdisciplinary RISP (Ross Ice Shelf Project) drilling through the Ross Ice Shelf took place in 1976-77 (Clough and Hansen, 1979). This programme followed the earlier RIGGS (Ross Ice Shelf Geophysical and Glaciological Survey) which took place between 1973 and 1978 (Bentley and Jesek, 1981; Bentley 1984). Bentley also summarized earlier work on the Ross Ice Shelf. The Circum-Pacific Council for Energy and Mineral Resources maps of Antarctica represent the most modern bathymétrie and geological syntheses of the region. The Southern Ocean atlas also summarizes hydrological data for the region (Gordon et al., 1982) and the Antarctic Bibliography, now published in 13 volumes by the U.S. Library of Congress, is a major source of references. In addition, a listing of all oceanographic stations in the Southern Ocean has been compiled by Anonymous (1984). The Antarctic Research Series published by the American Geophysical Union, now running to 47 volumes, contains a substantial amount of information on the region, particularly in marine biology. For instance, Jacobs (1985) has summarized the oceanography of the Antarctic continental shelf; this volume includes a copy of the GEBCO bathymétrie map of the shelf area (cf. Vanney et al., 1981; Johnson et al., 1982). An assessment of U.S. research priorities in Antarctica is given in Anonymous (1983a, 1986a, 1987a). A list of funding allocations within U.S. Antarctic research programmes in selected years is given by Shapley (1985).
Of the other interested nations, German efforts have concentrated on the tectonics and stratigraphy of the Ross Sea region starting in 1979 (Kothe et al., 1981; Tessensohn, 1984; Hinz and Kristoffersen, 1987). The Germans carried out seismic work in the Ross Sea in 1980 using the Explora, the French in 1981-82 also using the Explora, and the Japanese in 1982-83 using the Hakurei Maru (Anonymous, 1982; Behrendt, 1983a). A summary map showing the tracks of the multi-channel seismic surveys in the Ross Sea is given in Eittreim, Cooper, and Scientific Staff (1984). The Italians also carried out seismic work from the Explora in the seasons 1986-87,1987-88 and 1988-89 (Anonymous, 1988,1989). The Soviet vessel Ob began working in the Southern Ocean in 1956 (e.g., Zernova, 1970) and Soviet ships have carried out fisheries surveys in the Pacific Sector of the Southern Ocean since 1968 (USSR, 1985). In the mid 1970s, Soviet scientists developed a programme "Polar Experiment-South (POLEX-South)" to make a long-term study of the Antarctic Circumpolar Current. The results of this work, including a discussion of earlier Soviet physical oceanographic studies in the region, are summarized by Sarukhanyan (1985) (cf. Brigham, 1988). Soviet ships circumnavigated Antarctica in 1982-83 with the Dmitri Mendeleyev concentrating its scientific effort southwest of the Campbell Plateau (Anonymous, 1983b). Bek-Bulat and Zalishchak (1985) have reported phosphorite on a seamount in the vicinity of the Eltanin Fracture Zone. The Russian Atlas of Antarctica represented a major synthesis of existing data to that date (Anonymous, 1966a). Soviet ships have also started harvesting krill in the region (Worthington, 1986). Significantly, there has been no winter marine research project in the Ross Sea to rival the 1986 winter Weddell Sea Project undertaken by the German research vessel R.V. Polarstern (Hempel, 1988).
There are also a number of international programmes interested in this region such as the World Climate Programme (SCOR Working Group 74, 1985) and the World Ocean Circulation Experiment (Anonymous, 1986b). The International Whaling Commission has also carried out a number of minke whale assessment cruises. These generally include 2-3 Japanese and one Russian whale scouting vessels. The cruises which have taken place in the Antarctic Sector of the Pacific are the Third (1980-81) (130°E-170°W), the Fifth (1982-83) (60°W-120°W), the Sixth (1983-84) (120°W-170°W), and the Eighth (1985-86) (130°E-170°W). The Scientific Committee on Antarctic Research (SCAR) has been involved in a number of projects such as production of the BIOMASS Handbook Series and the BIOMASS Report Series. It has also sponsored a series of symposia on Antarctic geology and geophysics (e.g., Oliver et al., 1983) and on Antarctic biology (e.g., Siegfried et al., 1985). The FAO has put out species identification sheets, including species distribution and fishing grounds, for fishery purposes in the CCAMLR (Commission for the Conservation of Antarctic Marine Living Resources) area of the Southern Ocean (FAO, 1985).
Satellite observations are also becoming increasingly important, for instance to study ocean floor bathymetry (Dixon and Parke, 1983), sea ice distribution (Zwally et al., 1979, 1983, 1985; Gudmandsen, 1983; Robin et al., 1983; Comiso and Zwally, 1984), sea conditions (Mognard et al., 1983; Fu and Chelton, 1984) the relationship of ocean currents to bathymetry (Colton and Chase, 1983) or geoid anomalies (Driscoll and Parsons, 1988).
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