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McMurdo Sound and its ice-clogged waters extends about 55 kilometres (34 mi) long and wide. The sound connects the Ross Sea to the north with the Ross Ice Shelf cavity to the south via Haskell Strait. The strait is largely covered by the McMurdo Ice Shelf. The Royal Society Range rises from sea level to 4,205 metres (13,796 ft) on the western shoreline. Ross Island, an historic jumping-off point for polar explorers, designates the eastern boundary. The active volcano Mount Erebus at 3,794 metres (12,448 ft) dominates Ross Island. Antarctica's largest scientific base, the United States' McMurdo Station, as well as the New Zealand Scott Base are on the southern shore of the island. Less than 10 percent of McMurdo Sound's shoreline is free of ice. It is the southernmost navigable body of water in the world.
Captain James Clark Ross discovered this sound, which is about 1,300 kilometres (810 mi) from the South Pole, in February 1841, and he named it after Lt. Archibald McMurdo of HMS Terror. The sound today serves as a resupply route for cargo ships and for airplanes that land on the floating ice airstrips near the McMurdo Station. However, McMurdo Station's continuous occupation by human beings since 1957/58 has dirtied the harbor of Winter Quarters Bay.
The pack ice that girdles the shoreline at Winter Quarters Bay and elsewhere in the sound presents a formidable obstacle to surface ships. Vessels require ice-strengthened hulls and often have to rely upon escort by icebreakers. Such extreme sea conditions have limited access by tourists, who otherwise are appearing in increasing numbers in the open waters of the Antarctic Peninsula. The few tourists who reach the McMurdo Sound find spectacular scenery with wildlife to be seen, including killer whales, seals, Adélie penguins, and emperor penguins.
Cold circumpolar currents of the Southern Ocean reduce the flow of warm South Pacific or South Atlantic waters reaching McMurdo Sound and other Antarctic coastal waters. Bitter katabatic winds spilling down from the Antarctic polar plateau into McMurdo Sound demonstrate Antarctica's status as the coldest and windiest continent in the world. The McMurdo Sound freezes over with sea ice about 3 metres (9.8 ft) thick during the winter. The Antarctic summer causes the pack ice to break up. Wind and currents may push the ice northward into the Ross Sea, stirring up cold bottom currents that spill into the ocean basins of the world. Temperatures during the dark winter months at McMurdo Station have dropped as low as −51 °C (−60 °F). However, December and January are the warmest months, with average highs at −1 °C (30 °F) , according to USA Today.[ citation needed ]
McMurdo Sound's role as a strategic waterway dates back to early 20th century Antarctic exploration. British explorers Ernest Shackleton and Robert Scott built bases on the sound's shoreline as jumping-off points for their overland expeditions to the South Pole.
McMurdo Sound's logistic importance continues today. Aircraft transporting cargo and passengers land upon frozen runways at Williams Field on the McMurdo Ice Shelf. Moreover, the annual sealift of a cargo ship and fuel tanker rely upon the sound as a supply route to the continent's largest base, the United States' McMurdo Station. Both the U.S. base and New Zealand's nearby Scott Base are on the southern tip of Ross Island.
Ross Island is the southmost piece of land in Antarctica that is accessible by ship. In addition, the harbor at McMurdo's Winter Quarters Bay is the world's southmost seaport (Department of Geography, Texas A&M University). The access by ships depends upon favorable ice conditions.
McMurdo Sound during austral winter presents a virtually impenetrable expanse of surface ice. Even during summer, ships approaching McMurdo Sound are often blocked by various concentrations of first-year ice, fast ice (connected to the shoreline), and hard multi-year ice. Subsequently, icebreakers are required for maritime resupply missions to McMurdo Station. Nonetheless, ocean currents and fierce Antarctic winds can drive pack ice north into the Ross Sea, temporarily producing areas of open water.
A common event of previously unseen dimensions occurred on the Ross Ice Shelf in 2000 that wreaked havoc at McMurdo Sound more than five years later. The 282-kilometre (175 mi) long Iceberg B-15, the largest ever seen at the time, broke off from the Ross Ice Shelf in March 2000 (Antarctic Climate & Ecosystems: Cooperative Research Center). Then, on 27 October 2005, B-15 suddenly broke up.
Research based upon measurements retrieved from a seismometer previously placed on B-15 indicated that ocean swells caused by an earthquake 13,000 kilometres (8,100 mi) away in the Gulf of Alaska caused the breakup, according to a report by the U.S. National Public Radio. Wind and sea currents shifted a smaller, but still massive Iceberg B-15A towards McMurdo Sound. B-15A's enormous girth temporarily blocked the outflow of pack ice from McMurdo Sound, according to news reports.
Iceberg B-15A's grounding at the mouth of McMurdo Sound also blocked the path for thousands of penguins to reach their food source in open water. Moreover, pack ice built up behind the iceberg in the Ross Sea creating a nearly 150-kilometre (81 nmi) frozen barrier that blocked two cargo ships en route to supply McMurdo Station, according to the National Science Foundation.
The icebreakers USCGC Polar Star and the Russian Krasin were required to open a ship channel through ice up to 3 metres (9.8 ft) thick. The last leg of the channel followed a route along the eastern shoreline of McMurdo Sound adjacent to Ross Island. The icebreakers escorted the tanker USNS Paul Buck to McMurdo Station's ice pier in late January. The freighter MV American Tern followed on 3 February.
Similar pack ice blocked a National Geographic expedition aboard the 34-metre (112 ft)Braveheart from reaching B-15A. However, expedition divers were able to explore the underwater world of another grounded tabular iceberg. They encountered a surprising environment of fish and other sea life secreted within a deep iceberg crevasse. Discoveries included starfish, crabs, and ice fish. The latter were found to have burrowed thumb-sized holes into the ice.
The expedition reported an exceedingly rare and seldom witnessed occurrence of an iceberg exploding. Shards of ice erupted into the air as if a bomb went off, this only hours after divers surfaced and after the Braveheart moved away from the iceberg (National Geographic).
Polar winds are a driving force behind weather systems arising from three surface zones that converge at McMurdo Sound: the polar plateau and Transantarctic Mountains, the Ross Ice Shelf, and the Ross Sea. These surface zones create a range of dynamic weather systems. Cold, heavy air descending rapidly from the polar plateau at elevations of 3,000 metres (9,800 ft) or more spawns fierce katabatic winds. These dry winds can reach hurricane force by the time they reach the Antarctic coast. Wind instruments recorded Antarctica's highest wind velocity at the coastal station Dumont d'Urville in July 1972 at 320 kilometres per hour (200 mph) (Australian Government Antarctica Division).
Prevailing winds spilling into McMurdo Sound shoot between mountain passes and other land formations, stirring up blizzards known locally as "Herbies". Such blizzards can occur any time of year. Residents of McMurdo Station and Scott Base have dubbed the nearby White Island and Black Island as Herbie Alley due to winds that funnel blizzards between the islands (Field Manual for the U.S. Antarctic Program).
Overall the continent's extreme cold air scarcely holds enough moisture for snowfall. Consequently, Antarctica's blizzards are at times as much about wind stirring up existing snow as they are about new snowfall. For instance, the water equivalent from annual snow fall on Ross Island averages only 17.6 centimetres (6.9 in) (National Science Foundation). Snowfall in Antarctica's interior is far less at 5 centimetres (2.0 in). Noted as well are the McMurdo Dry Valleys on the western shores of McMurdo Sound where snow seldom accumulates.
Antarctica's shortfall in new snow does not lessen the continent's striking polar climate. Antarctica essentially doubles in size during the winter as the surrounding sea water freezes (Antarctic Connection). The subsequent annual summer melt of the estimated 18,000,000 square kilometres (6,900,000 sq mi) of ice that rings Antarctica creates the planet's largest seasonal climate event (USA Today). The result is a vertical circulation driven by a massive heat and energy exchange between ice, ocean, and atmosphere.
McMurdo Sound provides an important component in Antarctica's global effects upon climate. A key factor is the polar winds that can drive the sound's pack ice into the Ross Sea summer or winter. Frigid katabatic winds rake subsequent exposed water, causing sea ice to form. Freezing surface water excludes salt from the water below; leaving behind heavy, cold water that sinks to the ocean floor. This process repeats itself along Antarctica's coastal areas, spreading cold sea water outward into the world's ocean basins.
According to an interview with a climatologist Gerd Wendler, published in the National Science Foundation's Antarctic Sun, one could dive to the ocean floor anywhere in the world and encounter water from the coast of Antarctica. "Seventy five percent of all the bottom water, wherever you are, comes from Antarctica."
Source: U.S. National Science Foundation
Source: Australian Government Antarctica Division
A rich sea life thrives under the barren expanse of McMurdo Sound's ice pack. For example, frigid waters that would kill many other fish in the world sustain the Antarctic notothenioids, a bony "ice fish" related to walleyes and perch. The notothenioids feature an Antifreeze protein in their bloodstream that prevents them from freezing. Notothenioids account for more than 50 percent of the number of fish species in the Antarctic coastal regions and 90 to 95 percent of the biomass, according to the National Academy of Sciences for the United States.
What some sea creatures lack in numbers, they make up for in their visual presentation. McMurdo Sound divers encounter colorful examples of sea life, including bright yellow cactus sponges and green globe sponges. Starfish, sea urchins, and sea anemones are also present. The latter is noted for its wispy tentacles. Large sea spiders inhabit the deeps of the sound and feed on sea anemone, whereas swarms of Antarctic krill flourish in the upper depths of the icy waters. The shrimp-like krill is a key species in the Southern Ocean food chain for sea life ranging from the baleen whale to penguins. The sound is also home to soft coral, whose flexible form allows the creature to bend so as to feed off the ocean floor.
Antarctic penguins, famous for their waddling walk on surface ice, transform themselves into graceful and powerful swimmers underwater. The emperor penguins' pursuit of squid, fish, and crustaceans leads them to dive as deep as 500 metres (1,600 ft). However, the emperor can go deeper. Scientists have found that the penguin can reach 600 metres (2,000 ft) for short durations. The much smaller Adélie penguin is less ambitious. It feeds underwater for up to two minutes at a maximum depth of 170 metres (560 ft).
The Weddell seal out-dives even the emperor penguin. The seal can hold its breath for up to 80 minutes and reach a depth of 700 metres (2,300 ft) (Underwater Field Guide to Ross Island & McMurdo Sound). Scientists diving in McMurdo also encounter the leopard seal, and crabeater seal. The many-storied leopard seal is a ferocious predator that preys on warm-blooded animals, such as other seals and penguins, whereas the more sedate crabeater uses its unusual multilobed teeth to sieve krill from the water.
Seals have a natural enemy in the orca or killer whale of McMurdo Sound. The killer whale's voracious appetite leads it to consume up to 227 kilograms (500 lb) of food daily. The orcas feature black and white coloring, a large dorsal fin up to 1.8 metres (5.9 ft), and enormous strength and size — males can be 8 metres (26 ft). The whales travel in pods of up to 30 individuals and can swim up to 46 kilometres per hour (29 mph).
More than 50 years of continuous operation of the United States and New Zealand bases on Ross Island have left pockets of severe pollution marring McMurdo Sound's pristine environment. Until 1981, McMurdo Station residents simply towed their garbage out to the sea ice and let nature take its course. The garbage sank to the sea floor when the ice broke up in the spring, according to news reports.
A 2001 survey of the seabed near McMurdo revealed 15 vehicles, 26 shipping containers, and 603 fuel drums, as well as some 1,000 miscellaneous items dumped on an area of some 20 hectares (49 acres). Findings by scuba divers were reported in the State of the Environment Report, a New Zealand sponsored study.
The study by the government agency Antarctica New Zealand revealed that decades of daily pumping thousands of gallons of raw sewage from 1,200 summer residents into the sound had fouled Winter Quarters Bay, the harbor at McMurdo. The pollution ended in 2003 when a $5 million waste treatment plant went online.Other documented bay water contaminants include leakage from an open dump at the station. The dump introduced heavy metals, petroleum compounds, and chemicals into the water.
Zoologist Clive Evans from Auckland University described McMurdo's harbor as "one of the most polluted harbors in the world in terms of oil", according to a 2004 article by the New Zealand Herald.
Modern operations in McMurdo Sound have sparked surface cleanup efforts, recycling, and exporting trash and other contaminants by ship. The U.S. National Science Foundation began a 5-year, $30-million cleanup program in 1989, according to Reuters News Agency.The concentrated effort targeted the open dump at McMurdo. By 2003, the U.S. Antarctic Program reported recycling approximately 70% of its wastes, according to Australia's Herald Sun.
The 1989 cleanup included workers testing hundreds of barrels at the dump site, mostly full of fuels and human waste, for identification before they are loaded onto a freighter for exportation. The precedent for exporting wastes began in 1971. The United States shipped out tons of radiation-contaminated soil after officials shut down a small nuclear power plant.
Yet the very ships involved in supporting the export of McMurdo Station's waste present pollution hazards themselves. A study by the Australian Institute of Marine Science found that anti-fouling paints on the hulls of icebreakers are polluting McMurdo Sound.Such paints kill algae, barnacles, and other marine life that adhere to ship hulls. Scientists found that samples taken from the ocean floor contained high levels of tributyltin (TBT), a component of the anti-fouling paints. "The levels are close to the maximum, you will find anywhere, apart from ship grounding sites", said Andrew Negri of the institute.
Ships, aircraft, and land-based operations in McMurdo Sound all present hazards of oil spills or fuel leaks. For instance, in 2003, the build-up of two years of difficult ice conditions blocked the U.S. tanker MV Richard G. Matthiesen from reaching the harbor at McMurdo Station, despite the assistance of icebreakers. Instead shore workers rigged a temporary 5.6-kilometre (3.5 mi) fuel line over the ice pack to discharge the ship's cargo. The ship pumped more than 23 million litres (6.1 million US gallons) of fuel to storage facilities at McMurdo.
Officials balance the potential for fuel spills inherent in such operations against the critical need to keep McMurdo Station supplied with oil. A fuel tank spill in an unrelated onshore incident in 2003 spilled roughly 25,000 litres (6,600 US gallons) of Diesel fuel at a helicopter pad at McMurdo Station. The 1989 grounding of the Argentinean ship Bahía Paraíso and subsequent spillage of 640,000 litres (170,000 US gallons) of oil into the sea near the Antarctic Peninsula showed the environmental hazards inherent in supply missions to Antarctica.
Antarctica's extreme remoteness and hazardous travel conditions limit Antarctica tourism to an expensive niche industry largely centered on the Antarctic Peninsula. The number of seaborne tourists grew fourfold during the 1990s, reaching more than 14,000 by 2000, up from 2,500 ten years earlier.More than 46,000 airborne and seaborne tourists visited Antarctica during the 2007–2008 season, according to the International Association of Antarctic Tour Operators (IAATO).
This confederation of tour operators reports that only 5% of Antarctic tourists visit the Ross Sea area, which encompasses McMurdo Sound. Tourists congregate on the ice-free coastal zones during summer near the Antarctic Peninsula. The peninsula's wildlife, soaring mountains, and dramatic seascapes have drawn commercial visitors since the late 1950s, when Argentina and Chile operated cruises to the South Shetland Islands.
Tourists flights began in 1957, when a Pan American Boeing 377 Stratocruiser made the first civilian flight to Antarctica. Commercial flights landed at McMurdo Sound and the South Pole in the 1960s. Routine overflights from Australia and New Zealand took place between 1977 and 1980, transporting more than 11,000 passengers, according to Antarctica New Zealand, which manages Scott Base. One such flight, Air New Zealand Flight 901, crashed into Mount Erebus on the eastern shores of McMurdo Sound. The crash high on the slopes of the active volcano took the lives of all 257 people aboard the aircraft.
In 1969 the MS Explorer brought seagoing tourists to Antarctica (British Antarctic Survey). The cruise's founder, Lars-Eric Lindblad, coupled expeditionary cruising with education. He is quoted as saying, "You can't protect what you don't know" (IAATO). In the decades since then, ships engaged in Antarctic sight-seeing cruises have grown in size and number.
Infrequent Antarctic cruises have included passenger vessels carrying up to 960 tourists (IAATO). Such vessels may conduct so-called "drive-by" cruises, with no landings made ashore.
The Russian Kapitan Khlebnikov has conducted voyages to the Weddell Sea and Ross Sea regions since 1992. High-latitude cruises in dense pack ice are only achievable during the summer season, November into March. In 1997, the vessel Kapitan Khlebnikov claimed the distinction of being the first ship to circumnavigate Antarctica with passengers (Quark Expeditions). Passengers aboard the icebreaker make landings aboard Zodiac inflatable boats to explore remote beaches. Their itinerary may also include stops at Ross Island's historic explorer huts at Discovery Point near McMurdo Station or Cape Royds (Antarctica New Zealand). Additionally, the Russian icebreaker extends the reach of tourism by launching helicopter trips from its decks, including visits to sites such as the McMurdo Dry Valleys and areas noted for wildlife viewing.
The 'Spirit of Enderby has been conducting cruises to the Ross Sea region for many years, including McMurdo Sound. Although the Enderby has an ice-strengthened hull, the ship is not an icebreaker. The Enderby sports Zodiac inflatable boats, a hovercraft for Antarctica voyages, and all-terrain vehicles for over ice or overland travel. Land-based tourism in Antarctica, however, continues to be rare. Antarctica lacks a permanent land-based tourism facility, despite the annual surge in the number of visitors.
The International Association of Tour Operators (IAATO) has established voluntary standards to discourage tourists from disrupting wildlife. Nonetheless, large ships, carrying more than 400 passengers, may spend up to 12 hours transporting tourists to and from breeding sites. Such large-ship operations expose wildlife to humans far longer than smaller vessels.
An iceberg is a large piece of freshwater ice that has broken off a glacier or an ice shelf and is floating freely in open (salt) water. Small bits of disintegrating icebergs are called "growlers" or "bergy bits".
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).
Ross Island is an island formed by four volcanoes in the Ross Sea near the continent of Antarctica, off the coast of Victoria Land in McMurdo Sound. Ross Island lies within the boundaries of Ross Dependency, an area of Antarctica claimed by New Zealand.
The McMurdo Station is a United States Antarctic research station on the south tip of Ross Island, which is in the New Zealand–claimed Ross Dependency on the shore of McMurdo Sound in Antarctica. It is operated by the United States through the United States Antarctic Program, a branch of the National Science Foundation. The station is the largest community in Antarctica, capable of supporting up to 1,258 residents, and serves as one of three United States Antarctic science facilities. All personnel and cargo going to or coming from Amundsen–Scott South Pole Station first pass through McMurdo. By road, McMurdo is 3 kilometres from New Zealand's smaller Scott Base.
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 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 Ross Ice Shelf is the largest ice shelf of Antarctica. It is several hundred metres thick. The nearly vertical ice front to the open sea is more than 600 kilometres (370 mi) long, and between 15 and 50 metres high above the water surface. Ninety percent of the floating ice, however, is below the water surface.
Scott Base is a New Zealand Antarctic research facility located at Pram Point on Ross Island near Mount Erebus in New Zealand's Ross Dependency territorial claim. The research facility was named in honour of Captain Robert Falcon Scott, RN, leader of two British expeditions to the Ross Sea area of Antarctica. The base was set up as support to field research and the centre for research into earth sciences, and now conducts research in many fields, operated by Antarctica New Zealand.
Drift ice, also called brash ice, is sea ice that is not attached to the shoreline or any other fixed object. Unlike fast ice, which is "fastened" to a fixed object, drift ice is carried along by winds and sea currents, hence its name. When drift ice is driven together into a large single mass, it is called pack ice. Wind and currents can pile up that ice to form ridges up to several metres in height. These represent a challenge for icebreakers and offshore structures operating in cold oceans and seas.
The United States Antarctic Program is an organization of the United States government which has presence in the continent of Antarctica. Founded in 1959, the USAP manages all U.S. scientific research and related logistics in Antarctica as well as aboard ships in the Southern Ocean.
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.
This is a list of extreme points in Antarctica.
The Drygalski Ice Tongue or Drygalski Barrier or Drygalski Glacier Tongue is a glacier in Antarctica, on the Scott Coast, in the northern McMurdo Sound of Antarctica's Ross Dependency, 240 kilometres (150 mi) north of Ross Island. The Drygalski Ice Tongue is stable by the standards of Antarctica's icefloes, and stretches 70 kilometres (43 mi) out to sea from the David Glacier, reaching the sea from a valley in the Prince Albert Mountains of Victoria Land. The Drygalski Ice Tongue ranges from 14 to 24 kilometres wide.
USS Glacier (AGB-4) was a U.S. Navy, then U.S. Coast Guard icebreaker which served in the first through fifteenth Operation Deep Freeze expeditions. Glacier was first icebreaker to make her way through the frozen Bellingshausen Sea, and most of the topography in the area is named for her crew members. When built, Glacier had the largest capacity single armature DC motors ever installed on a ship. Glacier was capable of breaking ice up to 20 feet (6.1 m) thick, and of continuous breaking of 4-foot (1.2 m) thick ice at 3 knots.
Marble Point is a rocky promontory on the coast of Victoria Land, Antarctica, located at 77° 26' S latitude and 163° 50' E longitude. The United States operates a station at the point. The outpost is used as a helicopter refueling station supporting scientific research in the nearby continental interior such as the McMurdo Dry Valleys. Weather permitting, helicopters are able to fly in and out of the station 24 hours a day during the summer research season.
An ice pier is a man-made structure used to assist the unloading of ships in Antarctica. It is constructed by pumping seawater into a contained area and allowing the water to freeze. By repeating this procedure several times, additional layers are built up. The final structure is many metres in thickness, and strong enough to support container trucks. Operation Deep Freeze personnel constructed the first floating ice pier at Antarctica’s southernmost sea port at McMurdo Station in 1973. Ice piers have been in use each summer season since, at McMurdo's natural harbor at Winter Quarters Bay located at. The harbor is positioned on the southern tip of Ross Island.
Winter Quarters Bay is a small cove of McMurdo Sound, Antarctica, located 2,200 miles (3,500 km) due south of New Zealand at 77°50'S. The harbor is the southern-most port in the Southern Ocean and features a floating ice pier for summer cargo operations. The bay is approximately 250m wide and long, with a maximum depth of 33m. The name Winter Quarters Bay refers to Robert Falcon Scott's National Antarctic Discovery Expedition (1901–04) which wintered at the site for two seasons.
The Erebus Ice Tongue is a mountain outlet glacier and the seaward extension of Erebus Glacier from Ross Island. It projects 11 kilometres (6.8 mi) into McMurdo Sound from the Ross Island coastline near Cape Evans, Antarctica. The glacier tongue varies in thickness from 50 metres (160 ft) at the snout to 300 metres (980 ft) at the point where it is grounded on the shoreline. Explorers from Robert F. Scott's Discovery Expedition (1901–1904) named and charted the ice tongue.
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.
Tourism in Antarctica started by the sea in the 1960s. Air overflights of Antarctica started in the 1970s with sightseeing flights by airliners from Australia and New Zealand, and were resumed in the 1990s. The (summer) tour season lasts from November to March. Most of the estimated 14,762 visitors to Antarctica from 1999–2000 were on sea cruises. During the 2009 to 2010 tourist season, over 37,000 people visited Antarctica.
The Ross expedition was a voyage of scientific exploration of the Antarctic in 1839 to 1843, led by James Clark Ross, with two unusually strong warships, HMS Erebus and HMS Terror. It explored what is now called the Ross Sea and discovered the Ross Ice Shelf. On the expedition, Ross discovered the Transantarctic Mountains and the volcanoes Erebus and Terror, named after his ships. The young botanist Joseph Dalton Hooker made his name on the expedition.