Knowledge Encyclopedia Ocean

["1,800 kg (4,000lb) \u2013 the weight 151 of a big male walrus. Skull and tusks Tusks are massively enlarged canine teeth that grow from the upper jaw. Since the walrus does not chew its food its other teeth are quite small, and there are not many of them. These teeth are sometimes used to crush food. Mobile eyes A walrus\u2019s eyes protrude from its skull in such a way that it can look straight up as well as forward, giving the walrus a good all-round view of its surroundings. Sensitive whiskers Self-sealing nostrils More than 400 highly sensitive As with all seals, the walrus\u2019s whiskers on the walrus\u2019s snout nostrils close automatically enable it to locate prey by feel, to keep water out when the walrus is submerged. Special mapping the exact shape and muscles open them when size of anything they touch. it has to take a breath. Spectacular tusks The tusks of adult males are longer than those of females, growing to 100 cm (40 in) or more. The male with the most impressive tusks usually out- ranks all the other males.","152 polar oceans SEALS 3,700 kg (8,160 lb) \u2013 the maximum weight of the heaviest bull southern elephant seals. RIBBON SEAL Seals Histriophoca fasciata Highly insulated with thick fat or dense fur to keep them Location: North Pacific and Arctic warm underwater, seals and sea lions are well adapted Length: Up to 1.75 m (53\u20444 ft) for life in the icy polar regions. Many of them spend their entire lives at sea, either hunting in the near-freezing Instantly recognizable by its dramatic water or hauled out on the drifting pack ice. coat pattern, the ribbon seal breeds on Arctic pack ice around Alaska and eastern Most polar species are true seals with backward-pointing hind limbs, Siberia. It is specialized for movement which they use to drive themselves through the water. Conversely, fur over slippery ice, using the claws seals and sea lions can rotate their hind limbs, helping their mobility on its flippers, and is almost on land. True seals move clumsily on land, so many breed on floating helpless on land. ice where they are less vulnerable to attack \u2013 although this does not deter hungry polar bears or orcas. Many ice-breeding seals are at risk RINGED SEAL from climate change, which is reducing the area covered by sea ice. Pusa hispida White stripes Location: Arctic Both males and females have a striped pattern Length: Up to 1.6 m (51\u20444 ft) but the male\u2019s colours are particularly striking. Widespread throughout the Arctic and nearby seas, Ring pattern BEARDED SEAL the ringed seal owes its name to the pattern of silver-grey rings on its dark fur. Females breed Erignathus barbatus in isolated, snow-covered lairs amid tumbled Location: Arctic ice floes on the pack ice, entered from the Length: Up to 2.5 m (81\u20444 ft) water below. These lairs are targeted by prowling polar bears, which Like the walrus, this Arctic seal feeds mainly on can detect them by smell. bottom-living animals, which it detects with its very long, sensitive whiskers. It lives all around the Arctic, breeding on ice floes where many fall prey to orcas and polar bears. Newborn pup HOODED SEAL HARP SEAL ROSS SEAL Cystophora cristata Pagophilus groenlandicus Ommatophoca rossii Location: N. Atlantic and Arctic Location: N. Atlantic and Arctic Location: Antarctic Length: Up to 2.7 m (85\u20446 ft) Length: Up to 1.7 m (57\u204412 ft) Length: Up to 2.4 m (75\u20446 ft) Found in the icy seas around Greenland, the Harp seals breed in big colonies on the sea ice of Restricted to the icy fringes of Antarctica, hooded seal is named for the inflatable black eastern Canada, the Greenland Sea, and the Russian the Ross seal has very big eyes to help it locate \u201chood\u201d of the adult male, used to display to females Barents Sea. Notoriously, the white-coated pups squid and fish in the deep, dark water below the ice. and rivals. For maximum impact, it can also inflate were once targeted by seal hunters, but this is now the lining of one nostril like a pink balloon. outlawed in Canada. Harp seals spend most of their It is a solitary, elusive animal, and its lives at sea, hunting fish and shrimp-like krill. preference for thick pack ice means Inflatable Nasal sac that it is rarely seen except by hood White-coated pup research scientists or the crews The white fur is lost at of Antarctic icebreakers. the age of three weeks.","37 km\/h (23 mph) \u2013 the speed a leopard Crabeater seals are one of the most 153 seal can swim through the water. abundant large mammals in the world. ANTARCTIC STELLER\u2019S SEA LION FUR SEAL Eumetopias jubatus Arctocephalus gazella Location: Far north Pacific Location: Mainly sub-Antarctic Length: Up to 3.3 m (105\u20446 ft) Length: Up to 2 m (61\u20442 ft) One of six species of sea lion, this is the Unlike true seals, the fur seals and sea lions only species that lives in near-Arctic waters. swim using powerful strokes of their long It gathers on remote northern shores to breed, front flippers. They also use these as legs, each big male claiming a territory giving them much more mobility on land. and hoping to mate with any The Antarctic fur seal ranges further south female that enters the area. than most, hunting krill, fish, and squid in the Southern Ocean. But it avoids Female the iciest waters, breeding in colonies on rocky islands such as South Georgia. Woolly coat A layer of dense fur Up to 6 million beneath its outer coat keeps the seal warm. Antarctic fur seals breed on South Georgia islands. Male WEDDELL SEAL CRABEATER SEAL Multi-cusped LEOPARD SEAL teeth Leptonychotes weddellii Lobodon carcinophaga Hydrurga leptonyx Location: Antarctic Location: Antarctic Location: Antarctic Length: Up to 3.3 m (105\u20446 ft) Length: Up to 2.6 m (81\u20442 ft) Length: Up to 3.4 m (111\u20446 ft) Weddell seals live all around Antarctica on the Despite its name the crabeater This is the only seal that regularly preys on coastal sea ice, breeding on fast ice attached seal does not eat crabs, other warm-blooded animals. Found all around to the shore. They hunt fish and other animals instead it feeds on krill. Antarctica, it lurks in the water near and below in the water below the ice, using their teeth The elaborately shaped, ice floes, waiting to ambush penguins and to make and enlarge vital breathing holes. interlocking teeth of this smaller seals as they slip into the sea. seal form a sieve to strain mouthfuls of krill from icy Antarctic seas. Millions of crabeater seals live on drifting pack ice, where they are a prey of leopard seals. SOUTHERN ELEPHANT SEAL Enormous male Leopard spots A male southern elephant seal can Mirounga leonina The female Location: Antarctic weigh as much as a small truck. can weigh Length: Up to 5 m (161\u20443 ft) five times less than Elephant seals are named for the male\u2019s massive the male size, as well as the trunk-like extension of its nose that amplifies its roaring calls. Rival males fight to mate with as many females as possible, inflicting deep gashes on opponents with their teeth.","","Ice hunters As the sea ice starts to form and thicken off the coast of Alaska in autumn, a mother polar bear ventures out onto the edge of the ice, followed by her two young. After orcas, polar bears are the most powerful Arctic predators. They hunt almost exclusively on the sea ice, using their acute sense of smell to detect seals from up to 1 km (0.6 mile) away. A bear can crouch for hours by a seal\u2019s breathing hole, waiting to scoop it from the water and kill it with a single bite. If sea ice fails to form because of climate change, the bears will be unable to hunt and may starve.","156 polar oceans PENGUINS 18 million The estimated number of macaroni penguins nesting on the shores of Antarctica. EMPEROR PENGUIN Penguins Aptenodytes forsteri Often seen as clumsy and even comical when they are on land, Location: Antarctic shores and seas penguins are transformed into fast, agile, highly effective hunters Height: Up to 1.2 m (4 ft) when they dive underwater. The emperor is the biggest penguin. It hunts fish and Found only in the Southern Hemisphere, penguins are the most specialized squid, diving so deeply to find them that it can stay of all ocean birds. Every part of a penguin\u2019s body is adapted for hunting submerged for 20 minutes. Unlike other penguins it underwater and it is as efficient a hunter as any seal. Their excellent sometimes breeds in winter on fast ice (ice attached insulation allows them to hunt in icy Antarctic seas that teem with to the shore); the males incubate the eggs on their fish and shrimp-like krill. While few species nest on the shores of feet to stop them freezing. Antarctica itself, others form huge breeding colonies on the bleak, rocky islands that dot the Southern Ocean. KING PENGUIN Tight grip Aptenodytes patagonicus Like other penguins, an Ad\u00e9lie has bristle- Location: Sub-Antarctic like projections from its tongue and palate Height: Up to 95 cm (373\u20448 in) that help it grip slippery prey in its beak. The direction of the bristles stops the prey Although the king penguin looks from wriggling out and pushes it towards very like the emperor penguin, the penguin\u2019s throat. it has a different way of life. It hunts in open water Fish cannot escape at the fringes of the due to the inward- Southern Ocean, and forms huge facing bristles breeding colonies in spring on sub-Antarctic islands such as South Georgia. Chicks have brown down feathers MACARONI PENGUIN Eudyptes chrysolophus Location: Antarctic and sub-Antarctic Height: Up to 71 cm (28 in) This is one of seven species of crested penguins, all adorned with flamboyant yellow feathers on their heads. It is one of the most common penguins, with millions of pairs nesting on the Antarctic Peninsula and sub-Antarctic islands. It mainly eats krill, plus small fish and squid.","3 m (10 ft) \u2013 the height an Ad\u00e9lie penguin can 36 km\/h (22 mph) \u2013 the top speed of a 157 leap out of the sea to land on an ice floe. gentoo penguin through the water. Ad\u00e9lie penguin GENTOO PENGUIN Living further south than most penguin Pygoscelis papua species, the Ad\u00e9lie breeds on ice-free Antarctic Location: Antarctic and shores in summer and spends the rest of the year at sea. It preys mainly on krill, seizing sub-Antarctic them one by one with its sharp bill, and when it has caught enough it rests on drifting pack Height: Up to 81 cm (32 in) ice and icebergs. Found in the seas and islands around Antarctica, the gentoo has an unusually long tail. It can swim faster than any other penguin, and uses its speed to catch a variety of prey. It has a loud trumpeting call, given with its head thrown back and beak pointing skywards. Torpedo shape CHINSTRAP PENGUIN Thick, warm feathers slicked back against its Pygoscelis antarcticus body give the penguin Location: Antarctic and sub-Antarctic a streamlined shape. Height: Up to 77 cm (303\u20448 in) A million pairs of chinstrap penguins nest on volcanic Zavodovski Island in the far south of the Atlantic. Here, the heat of the active volcano melts the snow, helping to incubate their eggs in the chilly sub-Antarctic climate. Another three million pairs breed on ice-free shores and islands all around Antarctica. Underwater flight ROCKHOPPER PENGUIN Penguins use their short, densely feathered wings Eudyptes chrysocome to \u201cfly\u201d through the water. Location: Sub-Antarctic islands and seas Height: Up to 62 cm (243\u20448 in) Vital protection A white breast makes the Ad\u00e9lie hard These small, yellow-crested sub-Antarctic to spot against the pale sky, when penguins nest on rocky coasts where they viewed from below by predators such must leap from rock to rock to reach as the leopard seal. the sea. There are two very similar species, which bird breed on remote shores and islands AD\u00c9LIE PENGUIN as far north as Tristan da Cunha in the Atlantic. Pygoscelis adeliae Location: Antarctic shores and seas Length: Up to 71 cm (28 in) Diet: Krill, fish, and squid","158 polar oceans POLAR SEABIRDS 50 million \u2013 the estimated number of breeding pairs of Wilson\u2019s storm petrel living around Antarctica. Light and dark Tubenose WHITE-CHINNED PETREL The plumage is very As with all petrels, variable, ranging from the bill is formed of nine Procellaria aequinoctialis dark brown on its tail distinct plates, with tubular Location: Southern Ocean and wings to almost nostrils lying along the top. Length: Up to 58 cm (223\u20444 in) This gives these birds the white on its head. Mainly black, but often with a white patch beneath name \u201ctubenose\u201d. its bill, the white-chinned petrel hunts at sea for SOUTHERN GIANT PETREL krill, small fish, and squid, which it seizes from just below the surface of the salty seawater. In the Macronectes giganteus process it swallows a lot of salt, and like other Location: Southern Ocean petrels it expels the excess from a special salt Length: Up to 99 cm (39 in) gland connected to its tubular nostrils. Although they are closely related to the Well built albatrosses, and look similar, The white-chinned petrel the giant petrels have many has a large, bulky body. behavioural differences. Giant petrels are mainly scavengers that live on scraps picked Pale bill up from the breeding colonies of seals and penguins. They also prey upon helpless Wilson\u2019s storm petrel could be one of young, and kill and eat any injured adults they find. If threatened, they spray the most numerous foul-smelling oil at their enemies. seabirds on Earth. SOUTH POLAR SKUA SNOW PETREL Fluttering wings A storm petrel has a distinctive Catharacta maccormicki Pagodroma nivea fluttering, hovering flight as it Location: Antarctic Location: Antarctic searches the ocean for food. Length: Up to 55 cm (215\u20448 in) Length: Up to 40 cm (153\u20444 in) A notorious pirate, the south polar skua harasses This beautiful petrel other seabirds as they return to their breeding sites is well named, not and steals their fish. It nests on Antarctic shores in only because it is summer, but when winter closes in it pure white, but leaves for the north Atlantic and because it breeds north Pacific. mainly on the snowy continent of Antarctica. White flash It ranges further south than This mainly brown any other bird, and has even skua has distinctive been seen over the frozen white wing patches. wastes of the South Pole. At sea it feeds mainly among the pack ice, resting on icebergs. Snow white feathers BLACK-BROWED WILSON\u2019S STORM PETREL ALBATROSS Oceanites oceanicus Thalassarche melanophris Location: Oceans worldwide Location: Southern Ocean Length: Up to 20 cm (8 in) Length: Up to 93 cm (365\u20448 in) No bigger than a songbird, this fragile-looking Widespread throughout the Southern petrel lives on some of the wildest, windiest Hemisphere, the black-browed albatross seas on the planet. Despite this it is hugely is smaller than some other albatrosses, successful, with millions nesting on rocky but is just as skilled at soaring for hours islets around Antarctica. It has a curious habit over the waves with barely a wingbeat. It nests in colonies of pattering its feet on the ocean surface on remote islands, each pair as it gathers the small planktonic raising a single chick. animals that form its food. Downy chick","60,000 The number of tiny copepods eaten 159 each day by a songbird-sized little auk. KING EIDER Camouflaged female Somateria spectabilis Location: Arctic shores Length: Up to 63 cm (243\u20444 in) Wintering on coastal waters all around the Arctic Ocean, the king eider is a diving sea duck that feeds on bottom-living animals such as crabs and clams. In spring it moves onto land, nesting around the lakes that form when the winter snow melts. Polar seabirds In the polar regions, and especially around the frozen desert of Antarctica, the seas contain far more food than the land. A wide variety of seabirds come to prey upon the teeming animal life. Many of these birds remain at sea for much of the year, but return to the fringes of the land in spring to nest, lay eggs, and rear their young. Most of them hunt marine life, but others are scavengers or even pirates that ambush other birds and steal their food. LONG-TAILED Colourful SKUA breeding male Stercorarius longicaudus ARCTIC TERN Location: Arctic, sub-Antarctic Length: Up to 53 cm (203\u20444 in) Sterna paradisaea Location: Arctic and Antarctic Also known as the long-tailed jaeger, this is Length: Up to 36 cm (141\u20448 in) a predator and pirate, like most other skuas, often stealing the prey of other seabirds as This graceful seabird breeds in the Arctic, they return from hunting at sea. But unlike but spends the northern winter feeding many skuas it is a slender, elegant bird, in the oceans around Antarctica. This with slim, pointed wings and long, whippy epic migration means that the tail streamers. It breeds all around the High Arctic tern travels further each Arctic, but spends the northern winter over year than any other animal. warmer oceans south of the equator. Whip tail Both sexes have long tail feathers when fully adult. THICK-BILLED MURRE LITTLE AUK IVORY GULL Uria lomvia Alle alle Pagophila eburnea Location: Arctic, N. Atlantic, Location: Arctic, N. Atlantic, Location: Arctic Length: Up to 48 cm (19 in) and N. Pacific and N. Pacific Length: Up to 20 cm (8 in) The ivory gull is the only gull with pure white Length: Up to 43 cm (17 in) plumage. It is rarely seen south of icy Arctic seas, A tiny relative of the thick-billed murre, this hunts hunting at the edge of the pack ice in winter Auks are the northern counterparts of penguins, underwater in the same way, and flies low over and breeding on ice-free Arctic shores hunting at sea in the same way the sea with fast whirring wingbeats. It breeds in in summer. As well as taking fish by using their wings to swim colonies on the shores of Arctic islands, each pair and other animals, it underwater \u2013 although unlike nesting in a rocky crevice or scavenges the remains penguins they are able to beneath a boulder. of polar bear kills. fly. The thick-billed murre is the largest living species Stubby wings Pure white of auk; it nests in dense Adult ivory gulls colonies on sheer cliffs are white, but as facing Arctic seas. young birds they have black spots. Unique adaptation The spotted eggs have pointed ends and vary from white to blue in colour.","","Sleek swimmer Swooping up from the depths towards a gap in the Antarctic sea ice, an emperor penguin displays its effortless mastery of the underwater world. Able to dive to 550 m (1,800 ft) or more below the floating ice in search of fish, squid, and other prey, the emperor penguin holds the record for the deepest-diving seabird. Special adaptations allow it to conserve oxygen in its body, enabling it to stay submerged for an incredibly long time. Dives of more than 20 minutes have been observed.","","OCEANS AND US Beautiful and bountiful, the world\u2019s oceans provide people with many vital sources of food, energy, and recreation. However, these vast yet vulnerable expanses are under serious threat from climate change, high levels of pollution, and other forms of harmful human impact.","164 COASTAL COMMUNITIES HUMAN The oceans provided convenient transport and trade routes for IMPACT early civilizations. This gave rise to settlements along the coast, from small fishing villages to important trading posts. Today, Earth\u2019s oceans are an essential part of human life. one-third of the world\u2019s population lives along shores, and this Not only do oceans help to regulate Earth\u2019s climates, proportion is rising. Eight out of 10 of the world\u2019s largest cities, they are also vital for food, transport, trade, and from New York to Shanghai (below), are on the coast. energy. Although the oceans may appear to be a limitless resource, they are not. Marine life is being killed off by pollution, and overfishing has reduced some fish species to near extinction. Scientists are striving to understand more about the oceans so that we are better placed to protect marine life in the future world. OCEAN RESOURCES Fishing The oceans contain a wealth of resources that we rely on each day. Our early ancestors gathered seaweed and shellfish from shores, Offshore oil and gas fuel our cars and heat our homes, and metals caught fish, and hunted seals for food. Later they fished from boats are used in industry. Marine life not only provides us with food, and began simple freshwater fish-farming. Today, 3.2 billion people but also ingredients for medicines, skin care, and other products. rely on seafood for 20 per cent of their animal protein intake, and marine fish-farming is growing. Commercial fishing now amounts to Minerals and metals over 79 million tonnes (87 million tons) a year, and people across the world are eating more seafood than ever before. For centuries, people have evaporated seawater to obtain salt, such as the sea salt harvested in this Thai lagoon. The seas are also rich in other resources, which we are only just beginning to exploit. Sand, gravel, and limestone are essential supplies for the construction industry, and gold and diamonds are also extracted from the seabed. Still untouched are manganese nodules and black smokers on the seafloor, which contain copper, nickel, titanium, and other metals. Deep-ocean muds offer a future source of some rare metals used for mobile phones and computers. 1961: 9 KG (20 LB) 2017: 20.5 KG (45 LB) AVERAGE ANNUAL FISH CONSUMPTION PER PERSON Energy sources Modern oil exploration began on land more than 100 years ago, but rapidly moved offshore into shallow coastal waters. More than half of current oil and gas discoveries are beneath the deep oceans, with drilling in water depths of up to 2,000 m (6,600 ft) and reaching as far as 7,000 m (23,000 ft) below the seafloor. Over 60 per cent of commercial energy still comes from oil and gas, but sustainable sources, such as offshore wind farms (right), are steadily increasing, and power from tides and waves is also being harnessed across the world.","165 SEA CARGO OCEANS IN DANGER The oceans have provided vital trade routes for more than A fast-growing world population, crowded coastlines, extraction of 2,000 years. Today, more than 50,000 cargo ships carry oil and metals, global trade, and a booming tourist industry are all everything from cars to toys and oil to clothes, docking at having a profound impact on the world\u2019s oceans. Tonnes of waste, ports across the world. Supertankers and giant container ships sewage, and plastics are dumped into the seas each year. The are amongst the largest vessels ever built for the high seas. oceans are warming, losing oxygen, and becoming more acidic. Marine ecosystems are fragile, coral reefs are dying, and resources are limited \u2013 the oceans are under threat as never before. Pollution Semi-enclosed seas, like the Baltic, Mediterranean, and Black Sea, and those closest to megacities and industry, such as the Yellow and East China seas, are most at risk from pollution. Some are so polluted with sewage (right), oil, toxic chemicals, and fertilizer run-off that their marine life is largely dead or dying. Inland seas, such as the Caspian, and the Great Lakes of North America will find it hard to ever recover from more than a hundred years of pollution. UNDERWATER CABLES Habitat loss Climate change The first transatlantic telegraph cable was laid in 1858. Now The two sea habitats that are The effects of global warming on parts of the oceans are a busy network of communications cables, suffering extreme loss are coral the oceans are dramatic. Warmer oil and gas pipelines, and other seafloor installations. Today 99 reefs and mangrove wetlands. waters contribute to the loss per cent of all internet data is transmitted by submarine cables Together they are home to around of coral reefs and lead to more that stretch across oceans, laid as deep as Mount Everest is high. one-third of all marine species. extreme weather. As glaciers and Special ships are used to lay cables, while remotely operated More than 30 per cent of these ice sheets melt, sea levels rise, submarine vehicles are used to check for any problems. habitats has already gone and impacting on low-lying islands another 50 per cent is at risk. and nations. LEISURE AT SEA CONSERVATION One of the world\u2019s largest industries The negative human impact on is tourism, which accounts for 10 the oceans can be managed if per cent of world trade. Many tourists action is taken fast. There are seek sun-drenched beaches, water thousands of Marine Protected sports, and sailing marinas. Remote Areas, such as the Channel ocean islands and colourful coral Islands off California, USA, reefs are prized destinations for (right), for the conservation of snorkelling and diving. Ocean-going life and resources \u2013 but more cruise ships \u2013 the largest carrying are urgently needed. Oil-slick over 6,000 passengers \u2013 reach some dispersal projects, plastic waste of the remotest parts of the ocean, retrieval, and beach clean-up from around Antarctica to the islands operations are all helping to of the South Pacific. protect the world\u2019s seas.","Tension-leg oil platform Oil rig Crane winches 166 oceans and us OIL RIG supplies up There are many types of oil rig. Tension-leg Most of the energy used to power our homes, industry, to platform platforms are floating structures used in water and transport comes from fossil fuels, such as coal, from boats that is 200\u20132,000 m (660\u20136,600 ft) deep. They oil, and natural gas. More than a third of oil and gas are tethered to the ocean floor by strong cables. reserves are extracted from deep below the sea. Flare stack Oil from deep under the seabed is pumped up to the platform through long riser pipes. It is later Oil and gas formed over millions of years from the remains transported to shore for processing by tanker or of dead plankton buried under layers of sand and silt at pipeline. Large crews maintain operations on the intense heat and pressure. Oil rigs are used to drill for platform 24 hours a day, in harsh conditions. and extract these precious fuels. Offshore rigs are some of the biggest structures ever built. Helicopter Crew are transported Drilling tower to and from the rig Also known as a derrick, by helicopter. this holds the equipment used to drill and pump oil Living quarters from the underwater well. A rig can accommodate up to 500 workers, who typically work per cent of oil and gas discoveries in the 12-hour shifts, but spend four weeks onshore for every four on the rig. 50 last decade have been under the ocean. Helicopter landing pad Lifeboat Gas flare The average number of oil rigs The rig has Pockets of gas found trapped above the oil lifeboats for are burned, or \u201cflared off\u201d, if a rig is not set 1,600 in the ocean at any one time. evacuation in up to transport gas. Increasingly, this gas is an emergency. captured, to avoid waste and pollution. Floating columns Four huge columns support the large platform above the water. Anchor system Steel cables secure the floating platform to the seabed.","Sea life days \u2013 the maximum stay for workers Fish and other marine animals may shelter beneath the rig, although 30 on an oil rig without shore leave. oil drilling and extraction can disrupt wildlife and the environment. million barrels \u2013 the minimum Drilling through rock 500 amount of oil in a super-giant oilfield. To find offshore oil, first a survey exploring the rocks below the seabed is done to identify a potential site, then a mobile drilling rig is moved into position. A series of pipes designed to drill down through the rock to the oil, known as a drill string, is lowered to the seabed. If oil is found, the site is converted for production. Some rigs drill to depths of more than 7,000 m (23,000 ft) below the ocean floor. Blowout Drilling riser million years \u2013 the average time preventer holds drill controls oil string and 10\u201320 that oil or gas takes to form. carries mud flow and to surface seals well SEABED Wellhead SEDIMENTARY Drill string LAYERS OF ROCK Natural gas OIL-RESISTANT LAYER OF ROCK Oil trapped by rock Production risers Water Oil flows to the surface of Support framework the sea through riser pipes. 167 Cables are held rigidly At exploration (see panel), in place so that the rig a drill string is lowered through a drilling riser from does not move. the platform to the seafloor.","168 oceans and us WIND POWER Wind power Nacelle This sits on top of the tower A cleaner, safer, and sustainable alternative to fossil and houses the generator fuels, such as coal, is to harness the energy of the that turns the motion of the winds that blow across the oceans. rotor blades into electricity. A wind power station, or wind farm, is a group of tall Crane steel towers topped with rotating blades like those A huge crane carried of a windmill. As the blades spin in the wind, they on the jack-up boat lifts turn a generator, which converts this mechanical energy into electricity. Offshore wind farms are the components of more efficient than onshore ones, as sea winds a turbine into place. are stronger and steadier than winds on land. Towers ready Windfarm Rotor blades for installation Up to 81 m (266 ft) long, Offshore wind farms, such as the one seen each blade equals the here, are sited in fairly shallow water no wingspan of an Airbus more than 30 km (19 miles) from the A380 \u2013 the world\u2019s largest coast. The largest have more than a passenger plane. hundred turbines, the bases of which are sunk into the seafloor. An offshore Main tower electrical substation transfers the The tower is made from power to the grid on the mainland. tubular steel and stands up to 100 m (328 ft) high. Access ladder This allows workers arriving by boat access for inspection and maintenance. Jack-up vessel These specialized turbine- installation vessels have metal \u201clegs\u201d that lower and attach to the seafloor. It takes the onboard engineers less than two days to install a turbine. Then the legs are jacked back up, and the vessel moves on to place the next turbine in position. Power cable A cable sends the electrical power generated at each turbine to the wind- farm substation. Underwater base A steel foundation called a monopile is driven deep into the seabed and wedged in with concrete to secure the turbine.","Just one of the biggest wind turbines can By 2050, some experts believe that one-third of the 169 produce enough electricity to power 600 homes. world\u2019s electricity will be generated by wind farms. Tidal power Wave power Moving water is also used to generate electricity. Tides are a Harnessing the power of waves to generate electricity is still huge potential source of renewable energy. Large, low-lying underdeveloped. In 2000, the first small-scale project was dams called tidal barrages (pictured) generate electricity from launched off the coast of Scotland. This uses floating cylinders the power of tides. However, turbines placed in a fast-flowing (pictured) containing motors that are activated by wave motion. body of water, or tidal stream, are more widely used. The motors power a generator that produces electrical energy. Substation This structure collects electrical power generated by the turbines and feeds it directly to a conversion station. Conversion station The station converts the electrical current into the most efficient form for transmission to an onshore station. Mechanism turns Giant rotor blades the rotor blades to spin this shaft face into the wind Generator converts the motion of the spinning shaft into electrical energy Inside the nacelle The nacelle is the heart of the turbine, where wind is harnessed to create electricity. This structure contains the mechanisms that are set in motion by the turning rotor blades. A nacelle can be large enough to have a helipad on top.","170 oceans and us FISH FARMING 28.7 million tonnes (31.6 million tons) \u2013 the amount of fish produced each year by marine fish farms for human food. Fish farming Farmed fish The fish in this farm Around the world, people are eating more fish than are European sea bass. ever before. Just under half of the fish we eat is reared Other widely farmed in farms, rather than caught in the wild. marine fish are amberjacks and yellowtails. Fed on Also known as aquaculture, fish farming is one of the fastest- nutrient-rich pellets, growing food industries in the world. Many fish farms are located these fish thrive in inland and rear freshwater species, but about 35 per cent of all farm conditions. farmed fish comes from marine or coastal fish farms. In addition to fish, large numbers of shellfish, such as oysters and mussels, and seaweed are grown for human consumption. Buoy holds Wild fish circular net in place Multi-species farm Most fish farms rear only one species at a time, but this modern farm in the Mediterranean is cultivating several types of marine life at once. Fish are reared in a net enclosure close to the shore and the waste they produce provides nutrients for sea urchins and mussels growing nearby. Strings of seaweed help to maintain healthy, oxygen-rich water.","1 billion \u2013 the number of people who rely on 30 million tonnes (33 million tons) \u2013 the amount of seaweed farmed each year, 171 seafood as their main source of protein. used for food and as an additive in products such as toothpaste and paints. Buoys floating on Harvesting boat the surface keep A boat harvests seaweed ropes taut by winching the ropes up from the sea. Flowing current The current flows from the fish pen towards the mussels and seaweed, bringing fish waste laden with nutrients. Sea cucumbers Weights anchor Sea cucumbers on the seabed ropes supporting feed on fish waste that floats seaweed and down from above. This keeps shellfish the enclosure clean, and the sea cucumbers can be Seaweed harvested for food. Large quantities of seaweed are harvested each year for Net enclosure food and as an ingredient The net is suspended in other products. from a floating frame, keeping the fish enclosed Mussels in one small area. Mussels grow on ropes suspended from floating buoys. They feed on waste from the fish, sea cucumbers, and sea urchins, filtering nutrients from the water. Sea urchins Sea urchins are invertebrates with a spiny outer case. Their soft bodies inside are considered a delicacy in many parts of the world. Over-harvested in the wild, they are often cultivated in farms.","172 oceans and us FISHING TRAWLER 9.1 million tonnes (10 million tons) \u2013 the estimated amount of bycatch (sea life caught unintentionally) thrown back dead into the sea each year. Crane Unloading The large crane hauls The net empties the net full of fish out into the hold for processing. of the water and suspends it above the deck. Heavy nets When at sea, the openings of some nets\u2019 mouths are as large as a football pitch. As a result, they can haul in many tonnes of fish and other sea life on each trip. Trawler net There are several different types of trawler. Otter trawlers, like this one, are designed to catch fish that live near the seabed. Warp wires attached to the boat tow the weighted net behind. Otter boards (rigid boards on either side of the net) keep the net mouth open. Fish are funnelled into the net, collecting at the cod end. Trawler Propeller Warps (steel Engine room Deep hull wires) Powerful diesel engines turn the bladed propellers Otter board at the trawler\u2019s rear to push it through the water. Weight Floats Gutting fish Workers sort the fish, and Mesh remove the heads and internal Holes in the net allow organs. Any waste is made into smaller fish to escape. fishmeal, a product that is used to feed farm animals. Cod end The catch collects at the tapered end of the net.","4.6 million \u2013 the number of fishing vessels in operation worldwide. More 144 m (472 ft) \u2013 the length of the world\u2019s largest 173 than 80 per cent of these are small boats less than 12 m (40 ft) long. fishing vessel, the Annelies Ilena. Factory freezer trawler Fishing trawler This ocean-going fishing trawler hauls Braving stormy seas and long ocean voyages, sturdy a large catch in its net and unloads it trawler ships drag large nets through the water. Thousands into the ship\u2019s hull. Different-sized nets of fish can be caught by a single sweep of a net. are towed at different depths to catch particular fish species. Below decks, In 2018, 79.3 million tonnes (87.4 million tons) of fish were caught in the the fish are cut, processed, boxed, world\u2019s oceans. The boats that helped to land this catch range from small, and frozen all whilst out at sea. simple vessels to large ocean-going factory ships, which process and freeze their catches on board so they can stay at sea for weeks on end. Radar Radar navigation equipment Wheelhouse The wheelhouse is where helps the ship avoid other the crew navigate and check vessels in foggy conditions. weather and sea forecasts. Sleeping quarters Mess room Beds and storage lockers are The crew eat and provided for the 30\u201350-strong relax in the mess room. crew, who may be at sea for up to six weeks at a time. Filleting and skinning Storing boxed fish More than one-third of all fish stocks The skin and major bones Within hours of being caught, packaged fish are now overfished \u2013 of the fish are removed to produce ready-to-sell are stored in freezer taken more quickly than the fish can compartments deep reproduce so numbers cannot recover. fish fillets. Some types of fish are kept whole with in the ship\u2019s hull. This preserves the just the head removed. catch until the ship returns to dock.","Stilt fishing Perched precariously on wooden sticks bound together by twine, Sri Lankan fishermen work above the waters for hours at a time using simple rods and lines. This unique style of fishing began after the Second World War, when food shortages and overfishing in the most popular areas prompted some fishermen to seek out new spots. They first stood on shipwrecks, but later erected stilts to raise themselves above the water so as not to disturb the small herring and mackerel they hoped to catch.","","176 oceans and us SHIPS 121 km\/h (75 mph) \u2013 the fastest speed sailing record, set by the racing yacht Vestas Sailrocket 2 in 2012. Ships The bridge, or control room CONTAINER SHIP People may have taken to the seas as long of the ship, is always manned as 60,000 years ago, perhaps on primitive Speed: Up to 37km\/h (23 mph) rafts. Today, the oceans carry all types of by one or more officers Length: Up to 400 m (1,312 ft) vessel, from tugs to tankers and sailing boats to submarines. Over half the world\u2019s 100,000-strong fleet are merchant ships carrying trade goods, while about 10 per cent are naval vessels. Cruise ships and fishing boats make up most of the rest. Vessels such as oil tankers and container ships, which are some of the largest ships on the ocean, are the most efficient way of transporting bulk fuel and heavy goods around the world. SPEED BOAT RACING YACHT TUGBOAT Speed: Up to 160 km\/h (100 mph) Speed: Up to 120 km\/h (75 mph) Speed: Up to 27 km\/h (17 mph) Length: Up to 15 m (50 ft) Length: Up to 15 m (50 ft) Length: Up to 30 m (98 ft) Small, high-powered motor boats are popular for A racing yacht is a medium-sized Powerful and sturdily built, tugboats are the cruising and sports such as fishing and racing. The sailing boat with a lightweight hull work-horses of harbours and river estuaries. They world water speed record was set in 1978 by a and a tall mast to carry large are built to manoeuvre other vessels by pushing, boat called the Spirit of Australia, which reached sails. From weekend regattas pulling, and towing, often working in teams 511.1 km\/h (317.6 mph) powered by turbo-jet to Olympic events, yacht around the largest ships. propulsion. Many modern speed boats can easily racing is highly popular. The average 160 km\/h (100 mph) over calm seas. Ocean Race, contested over Tugs carry 72,000 km (39,000 miles), equipment such Propulsion is provided by is one of the sport\u2019s as towlines and an outboard motor greatest challenges. lifting gear Large sail called a spinnaker catches the wind SEARCH AND RESCUE BOAT Powerful HOVERCRAFT searchlight Speed: Up to 74 km\/h (46 mph) Speed: Up to 137 km\/h (85 mph) Length: Up to 35 m (115 ft) Length: Up to 58 m (190 ft) Maritime search and rescue teams These vessels skim on a cushion of air over water, operate a range of vessels for coastal land, mudflats, beaches, and ice floes. The air and deep-sea missions. The boats are currents that lift them are blown beneath the fast, robust, highly manoeuvrable, craft by fans. Hovercraft were once common as and can withstand very rough seas. Many even right themselves commercial ferries, but are now mostly used for if they are overturned military and leisure purposes. by freak waves. Skirt prevents air escaping","458.45 m (1,504 ft) \u2013 the length of the oil tanker 19,000 The number of containers carried 177 Jahre Viking, the longest ship ever built. on the largest merchant ships. The true giants of the seas, container ships transport bulk cargoes of loose products, such as AIRCRAFT CARRIER construction materials and coal, and carry all kinds of non-perishable items in huge steel containers. These ships need specialized ports and take nearly 10 km (6 miles) to slow down and stop. Speed: 72 km\/h (45 mph) Length: Up to 342 m (1,122 ft) This vessel is the largest warship and usually the most important ship in a naval fleet. It is a floating airbase with a huge flight deck for take-offs and landings. Aircraft carriers can hold war planes, such as bombers and fighters, as well as helicopters and reconnaissance planes. Angled deck assists take off CRUISE SHIP TALL SHIP SUBMARINE Speed: Up to 56 km\/h (35 mph) Speed: Up to 27 km\/h (17 mph) Speed: 37 km\/h (23 mph) Length: Up to 362 m (1,188 ft) Length: Up to 111 m (364 ft) Length: Up to 175 m (574 ft) Cruise liners offer luxury holidays, taking High-masted, wooden-hulled sailing ships A submarine can patrol underwater for months tourists to exotic locations such as the islands plied the seas for exploration, trade, warfare, at a time, adjusting its air- or water-filled ballast of the Caribbean or the Indian Ocean, the and scientific discovery for more than four tanks to dive lower or rise to the surface. Norwegian fjords, or the icy seas off Antarctica. centuries. They were slowly replaced by steel- Submarines have been essential to naval warfare Some cruise liners rank amongst the largest hulled steam ships in the mid-1800s, but some since World War I. Today, they may be heavily ships ever built, carrying more than 6,000 are still built today for tourism and racing. passengers and 2,000 crew. armed with nuclear missiles. A fully rigged tall Conning tower ship carries This structure rising square sails from the hull houses on two or the sub\u2019s navigation three masts and communication equipment. RESEARCH SHIP OIL TANKER Speed: Up to 37 km\/h (23 mph) Speed: 37 km\/h (23 mph) Length: Up to 210 m (689 ft) Length: Up to 458 m (1504 ft) Many ocean research expeditions have taken Tankers come in all sizes, and include the place over the past 250 years. Modern research biggest ships ever built. Some are longer ships are equipped with laboratories and than New York\u2019s Empire State Building is tall: specialized instruments, and some carry small roughly four football pitches end-to-end. self-guiding vessels for underwater investigations. These supertankers are designed to transport liquids and have the capacity to carry The polar research more than four million barrels vessel RSS Sir David of crude oil. Attenborough","178 oceans and us POLLUTION 8 million tonnes (9 million tons) of plastic end up in the oceans every year. Pollution Pollution hotspots Every year, human activities expose the planet\u2019s vulnerable Human impact along densely populated coasts can oceans to increasing amounts of pollution. Harmful substances produce a wide range of different ocean pollutants. and materials enter ocean waters, threatening marine life and Whether it\u2019s washed, blown, dumped, or the result upsetting the delicate balance of ocean ecosystems. of an accident, much of the pollution reaching the ocean was produced originally on land. This pollution takes many forms, from air pollution, some of which Effluent falls back to Earth, to plastic waste. Some pollutants disperse Raw sewage can lead to the rapid growth of more easily than others, but in large amounts all damage algae, which can release poisons into the water. the oceans. Oil is toxic to life, but small amounts from natural seeps degrade faster than harmful major spills. Raw sewage and run-off farm waste release excess nutrients, which make algae grow, and disease-causing germs into the water. Toxic chemicals Washed-up waste from pesticides and industrial Waves frequently draw waste can enter the food chain ocean pollutants and waste back to shore, as they build up in the bodies\u00a0 contaminating coastlines. of living creatures. Factories Gold mining Crop dusting Greenhouse gas Toxic compounds of Harmful pesticides may be emissions contribute cyanide and arsenic, used blown by winds out to sea, and to global warming and to extract gold from ore, fertilizer run-off can trigger ocean acidification, while can enter water sources waste water run-off may harmful algal blooms. contain toxic chemicals. and reach the sea. Sewage pipes In some places, underground pipes pump untreated sewage directly into the sea, polluting the water and harming life. Rubbish islands Plastic waste and other rubbish dumped on land and washed into rivers can flow out to sea. There, circulating currents known as gyres may cause it to congregate, forming large, floating islands of rubbish such as this waste mass engulfing Roat\u00e1n Island in the Caribbean Sea. With typical lifetimes of up to 500 years before they biodegrade, waste plastics pose major problems for ocean life. They trap and kill marine animals and stop sunlight reaching phytoplankton that rely on light to produce food. In addition, this plastic debris breaks down into microplastics \u2013 tiny particles of plastic \u2013 which can then enter the food chain.","80 per cent of microplastics in the oceans come from plastic 179 waste dumped on land that then washes into oceans. Oil spills If wrecked, an oil tanker can discharge tens of thousands of litres of oil into the sea. Ghost fishing Thousands of fishing nets are lost or dumped in the oceans every year. These entangle, suffocate, and kill tens of thousands of turtles, fish, seals, and other marine life. Nuclear waste Low-level radioactive waste has been dumped at more than 50 sites in the Atlantic and Pacific oceans. Wrecked aeroplane The fuel from wrecks of ships and planes disperses rapidly, and the sunken vessels can become artificial reefs for marine life. Up to 2,000 shipping containers holding a range of contaminants are lost overboard every year. Gas pipeline Fur, feathers, and oil Underwater pipes transfer gas from place to place. Damage Oil destroys the ability of fur and or corrosion to pipes can feathers to repel water and so keep sea lead to liquefied natural gas mammals and birds warm. It can also contaminating the seawater. kill if swallowed. Vast amounts of oil enter the ocean every year from leaks, Ferry boat spills, and natural seepage. In 2010, the Marine pollution is worst in seas that Deepwater Horizon oil well spilt more are partially enclosed by land, such than 4 million barrels (636 million as the Mediterranean, and near coasts, litres) of oil, forming a 149,000-sq-km where busy shipping lanes and ferry (57,500-sq-mile) slick in the Gulf of routes are streaked with oil and diesel. Mexico, devastating marine life. Eating plastic waste Lots of plastic waste ends up in the sea and washes up on beaches. Seabirds often mistake the coloured plastics for food. It can lodge in their throat or gut, killing them. Around one million seabirds and 100,000 marine animals die this way each year.","Plastic pollution In the rubbish-strewn waters of Verde Island Passage in the Philippines, a crab struggles to escape from a single-use plastic cup. This expanse of water is one of the most biodiverse regions of marine life in the world, with dozens of new species discovered there every year. Sadly, many of the sea creatures are under threat from the rising tide of plastic waste that is dumped or washed into the ocean, which traps, entangles, or chokes helpless animals. These floating rubbish tips also impact more than two million people in the region, who depend on the waters for their livelihood.","","182 oceans and us CLIMATE CHANGE 30 per cent \u2013 the increase in acidity of the oceans over the last 250 years. Climate change Ocean acidification Even though the oceans are vast, the changes that humans Seawater is far more acidic today than it was are making to the planet and its climate are having a devastating before industrialization began. This is because impact beneath the waves. excess carbon dioxide \u2013 from clearing forests and burning fossil fuels for energy, transport, As we cut down forests and burn fossil fuels, such as coal and oil, levels of carbon and industry \u2013 dissolves in the water, making dioxide in the atmosphere are rising. Carbon dioxide is known as a greenhouse gas it more acidic. Acid in the oceans reacts with because it traps the Sun\u2019s heat. More of it traps more heat, warming up the world minerals in the shells of marine creatures, and its seas, and even turning the oceans acidic. Not only does climate change releasing the minerals into the water, leaving threaten to flood coastlines and change weather patterns, but many kinds of the shells thinner and more fragile, and making marine life are less likely to survive \u2013 including spectacular reef-building corals. it harder for the creatures to rebuild them. Deforestation As land is cleared of trees for farming, industry, and urban growth, less carbon dioxide is absorbed from the atmosphere and more is released into it. Every day, the world\u2019s oceans absorb A forested world High levels of tree cover on land help to absorb 20 million tonnes carbon dioxide, reducing the amount entering (22 million tons) of carbon dioxide. the atmosphere and reaching the oceans. Rich reefs Colourful corals Coral reefs support rich and Brightly coloured corals thrive in abundant marine life, including low-acidity water, extracting readily vivid clownfish, damselfish, available minerals from the water and butterflyfish. to strengthen their structures. Body building Mutual benefit 2 Present day Shellfish such as crabs and sea urchins Corals protect and get some Warmer oceans carry less oxygen, making extract the minerals they need from water nourishment from algae living it harder for certain animals to thrive. Migration to build their hard shells, or exoskeletons. in them, which \u2013 like trees \u2013 patterns may be affected as changes in temperature use light energy to make food disrupt ocean currents. More acidic water weakens 1 Healthy seas shells and rocky corals, and stops the eggs of ocean Before the widespread burning of coal, oil, and from carbon dioxide. creatures \u2013 such as fish \u2013 from developing properly. gas, lower levels of carbon dioxide in the atmosphere and oceans meant that seawater was far less acidic. In this environment, coral and other forms of marine life were able to build and maintain their skeletons and other hard structures, and fish flourished.","475 billion tonnes (525 billion tons) of carbon dioxide have been 25 per cent of all marine species 183 absorbed by the oceans since the start of the Industrial Revolution. live in and around coral reefs. Climate disruption Rising seas The oceans help to control Many low-lying islands, climates. They absorb coastal towns, and cities carbon dioxide, reducing around the world could its greenhouse effect, and become uninhabitable if their currents circulate sea levels continue to rise. warm tropical waters with This is a result of melting cold polar ones, preventing ice caps and glaciers, and extremes. Warmer waters of seawater expanding as make devastating storms it gets warmer. Here, a such as Hurricane Dorian boy rides his bike through (pictured right) likely and floodwaters on the Pacific could disrupt the climate. island of Tuvalu. Factories Emptier oceans Industries, homes, and transport burn Plankton and fish populations fossil fuels, such as oil and coal, for may be affected, while numbers power. When this happens, the fuel of some kinds of jellyfish that reacts with oxygen in the air to create are tolerant of more acidic and carbon dioxide. A growing human warmer waters may rise. population and rising demand may see industries maintain or even increase emissions despite the known threats. Dying corals Weakened shells 3 Looking ahead Growing grasses Warmer waters cause coral The shells and hard skeletons of If fossil fuel burning continues and carbon Seagrasses absorb carbon sea urchins and other creatures dioxide emission rates are not lowered, the oceans dioxide, so may help to bleaching, as stressed are weakened and made more could become 150 per cent more acidic by 2100. combat ocean acidification. corals expel the tiny algae vulnerable to injury by the more Corals, shellfish, and other hard-shelled marine species that live in them and give acidic water. may struggle to survive. However, some soft-bodied Broken reefs them their vibrant colours. animals, such as jellyfish, may actually thrive. Coral reefs may be damaged Without the algae to help beyond repair by bleaching feed them, corals may die. and acidification. This makes them unable to build their skeletons, meaning that they can no longer support such a rich abundance of life.","184 oceans and us OCEAN WATCH 5,000 The approximate number of plastic items found on every 1.6 km (1 mile) of beach in the UK. Ocean watch Monitoring the oceans The oceans are under threat from pollution, climate change, In order to protect and conserve the and overfishing. One of the ways we can conserve the oceans ocean, scientists are using a range of for future generations is by first studying them. devices to gather vital information about the oceans \u2013 from anchored buoys and The major challenge of monitoring the world\u2019s oceans is their sheer scale. tide gauges to unmanned vehicles that Oceans cover 71 per cent of the planet\u2019s surface and can reach depths of more can roam thousands of kilometres per than 10,900 m (35,760 ft). To cover this range, researchers are increasingly mission. Some instruments measure turning to technology for assistance. This allows experts to collect large amounts the water\u2019s temperature and chemistry, of data from different areas and depths in the ocean and then compare this whilst underwater robots monitor information over time to assess what changes are occurring and why. marine life at close hand. Tower next to the tide house SoFi monitors winds and air temperature This soft-bodied robot that resembles a fish passes through coral reefs without disturbing the marine life. Its sensors and high-definition video cameras film and monitor the condition of shallow-water coral. Tide gauge station Side-mounted fins alter their These scientific stations angle to help SoFi rise or fall measure and record the height of the surrounding water, Shark tagging producing accurate records of sea levels and high and low Individual creatures, such as this young blacktip reef tides. Some stations also shark, can be monitored by fitting a tag to their body. Tags contain sensors that measure communicate with satellites to track the location, direction, wind and air temperature. and depth of the shark so that researchers can learn more about its migrating, feeding, and breeding habits. Beach clean-ups Tag attached to Scientists are not the only people monitoring oceans and first dorsal fin coastal communities. There are worldwide efforts to tidy up beaches, as seen by these students who are removing waste \u2013 much of it plastic bottles and shopping bags \u2013 from a beach in the Indonesian village of Ujong Blang.","4,078 The number of Argo floats 80 per cent \u2013 the area of the world\u2019s oceans that 185 deployed at sea, as of March 2020. have yet to be fully observed and mapped. Satellite sensing Satellites are used to monitor the ocean surface. They measure the heat energy emitted from the ocean, and this data can be gathered to build up global sea surface temperature maps that are useful in climate change research. Argo float Survey ships Thousands of these temperature and These vessels can deploy buoys, floats, salinity (salt) measuring devices form a and underwater robots. They can also global network. In a 10-day cycle, each take multiple water samples from float descends to a depth of up of 2,000 m different depths using a circular frame, (6,600 ft). When it resurfaces, it transmits called a rosette, containing niskin bottles its data via satellite to researchers on land. (pictured below the water\u2019s surface). Smart buoy Echo Voyager Powered by solar panels, this Guided by motion sensors buoy is packed with sensors that and using sonar to detect obstacles in its path, Boeing\u2019s measure the wind and other Echo Voyager is an unmanned weather conditions above the underwater vehicle (UUV). surface. Submerged sensors can Scientists deploy it to patrol measure the ocean\u2019s chemistry, such and monitor the condition as its acidity and oxygen levels. of seabeds in deep waters. Rosette typically holds 12 or 24 niskin bottles Each float takes around six hours to descend from the surface to 1,000 m (3,280 ft)","","OCEAN MAPS Humans have always explored and mapped the world\u2019s oceans, but recent technology has allowed us to see and understand these vast regions as never before. From the tropical Pacific to the chilly Arctic, each of the five oceans is home to unique geographical features, habitats, and creatures.","188 The world\u2019s oceans are one vast expanse of water stretching around the globe, divided into five main GLOBAL areas: the Arctic, the Atlantic, the Indian, the Pacific, OCEAN and the Southern oceans. Near coastlines, parts of these can be grouped into smaller seas \u2013 bodies of water usually partially surrounded by land. ARCTIC OCEAN Queen Chukchi Canada Beaufort Elizabeth Greenland Sea Basin Sea Islands Baffin Baf n Greenland I sl Bay Denmark Strait BIcaSnekelaandNoNrwoSergetaihan and Mid - Atlantic Ridgevis Strait Sea Hudson Iceland Bay DaLabSreaador FCr ahcatrul iree- TrenchGulf of Gibbs Basin l l Alaska Zone Rocka Aleutian Rocky Mountains antic Ridge Mendocino Fracture Zone NORTH GNraenwdfoBuanndklasnodf AMERICA Northeast M urray Fra cture Zone n e Sohm Mid- Atl FEraacsttuArezoZroense Molo kai Fract ure Zo Plain Sargasso P A C I F I CHaIswlaanidiasn Gulf of Kane Mexico Sea Nares Fra ct u r e Zone Cape Verde Clarion Fracture Zone Middle America Plain Basin AFRICA Guatemala Pacific Zone Trench Caribbean Sea AT L A N T I C Christmas Ridge Clipperton Fracture Doldrums Fracture Zone Gallego sBaesiGnal\u00e1paCgooRcisdgeos OCEAN Rise Basin Islands ench Guinea Basin i SOUTH Ascension Fracture Zone AMERICA Angola Manihiki Pacific Peru R Plateau Basin rT Brazil Basin Tahiti O C E A N Nazca Ridge Basin Southwest Sala y Gomez Ridge ile Andes vis Ridge Pacific Easter Island Basin h Rio Grande Wal Cape Challenger Fracture Zone Rise Basin East C Chile Argentine Rise - Basin RLiodugiesville u r e P Pacific-Antarctic Ridge Eltanin Fracture Zone Southeast Falkland Islands Pacific SOUTHERN OCEAN Basin Cape Passage Scotia Atlantic-Indian Ridge Horn Sea Atlantic-Indian Drake Weddell Weddell Plain Sea A N TA R C T I C A","189 THE PACIFIC OCEAN Ocean areas Atlantic Pacific Ocean IS THE BIGGEST AND Ocean 47 per cent of the ALSO THE DEEPEST OCEAN. Stretching from east Asia to the west coast 23 per cent ocean surface of the Americas, the IT ALSO HAS THE LONGEST Pacific Ocean takes Southern Indian COASTLINE AT 135,665KM up the majority of the Arctic Ocean Ocean ocean surface. The Ocean 20 per cent other oceans cover 4 per cent 6 per cent (84,298 MILES) LONG. smaller areas. Svalbard Franz Josef Kara ARCTIC OCEAN Land Sea Barents Novaya Laptev Sea East Sea Zemlya Siberian Sea Sea of AAleluetuitaina n Island s Okhotsk Trench EUROPE Kuril Trenc Black Sea Caspian ASIA Sea ofrench SEemampeoruonrts Sea Japan Izu-OTgreanscahwara Mediterranean Sea Himalayas np a Northwest GPeurlfsian Ja Paci c East Trench h Basin China Red Sea Sea T Ryukyu Arabian Philippine M iodu-nPtaaci if i c South M n s Aden Se Chagos-Laccadive Plateaua Bay of China PPhhiilliippppinienTeren Gulf of Carl Ridge Bengal Sea Sea Melanesian berg Great Rift Valley Sri Lanka Mariana Basin Somali Basin s Ninetyeast Ridge PACIFIC Maldives ch KapingamRiasre SumatraJ Borneo Ma Ceylon angi O C E A N Seychelles scarene Plateau Plain ava T Java New r ench Guinea Mid-Indian Cocos Basin Basin Arafura Sea New Great Barrier Reef Madagascar INDIAN Coral Hebrid North Mid-Indian Ridge Sea Lord Fiji Basin Fiji Mauritius AUSTRALIA es Trench Kermadec Trench O C E A NCape of South Fiji Good Hope Basin Agulhas Basin SoMuthawdBaeasgstainIsncdaiarCnBrRaiodsgzeient Broken Ridge Perth Howe New Basin e Zealand Crozet Natal Tasman Ris Chatham Basin Rise Basin Plateau PlKateeraguuelen So uthea st In d i a n Tasmania Southeast Indian Basin Ridge Tasman Campbell Sea Plateau S O U T H E R N O C E A NBasin Enderby Plain Davis Sea A N TA R C T I C A","190 ocean maps ARCTIC OCEAN 15 million sq km (5.8 million sq miles) \u2013 the area covered by Arctic sea ice in winter. ocean data P h i l i pSpeian e Himalayas ARCTIC OCEAN ASIA Area: 12,173,000 sq km (4,700,000 sq miles) Average depth: 990 m (3,250 ft) Deepest point: 5,608 m (18,400 ft) Winter freeze In winter, floating sea ice covers most of the Arctic Ocean. Mid-Paci c Mountains Kuril Trench Siberia OkSheotasokfPNaocrithcwBeasstin Migrating whales Emperor Seamounts Laptev Kara Novaya Beluga whales spend Sea Sea Zemlya the winter hunting in Trough open water beyond the East NansenFranLzanJdosefBaSreenats pack ice. As the ice Aleutian Siberian Sea AmunGdLasokemkneBolBanRsaoiindssMgionevakarovRBidagsein melts they migrate to shallow coastal waters Em Basin all around the Arctic. PACIFIC peror Aleutian Trench ARCTIC Svalbard SBeeraing MeRniddgeeleyev Baltic PlCahteukacuhi Chukchi OCEAN + North Pole GreeSnelaandNoNBroSwaresweaingeiagSnieaan Bering Strait Sea Wandel OCEAN Canada Sea Basin BeaSuefoart Reykjanes Ridge Bering Strait Hawaiian Gree Some 15,000 years ago, Islands Gulf of Queen Denmark Strait Alaska during the last Ice Age, Elizabeth Baf n nland Iceland this strait was dry land, MendocinoMFurrarcatyurFeraZcotunree Zon Islands Baffin Bay allowing humans to I reach North America Da slandvis Strait from Eurasia. Labrador Sea LaBbarsaindor e Hudson Bay NORTH Newfoundland Basin AMERICA ATLANTIC Icy waters The Queen Elizabeth Islands were first mapped by explorers looking for a sea route from the Atlantic to the Pacific through the Arctic. For centuries navigators searched for a way through the treacherous, ice-bound waters. Norwegian explorer Roald Amundsen made the first complete passage in 1906.","13 per cent \u2013 the present rate at which summer sea ice 1,500 The number of lives lost when the ocean liner RMS Titanic 191 in the Arctic Ocean is shrinking each decade. hit an iceberg that drifted south from Baffin Bay in 1912. Arctic Ocean Shrinking ice Lying around the North Pole and virtually surrounded by Climate change has raised the annual average air the continents of North America and Eurasia, the Arctic Ocean temperature over the Arctic Ocean by 3\u00b0C (5.4\u00b0F) since is the smallest of the world\u2019s oceans. In winter it freezes 1970. This is making winter sea ice thinner and less likely to form at all. In summer it melts faster, leaving over to create a vast sheet of floating ice. a smaller area of ice in the far north. It may not be long before all the Arctic sea ice melts away in summer, The ocean floor is expanding at the Gakkel Ridge, near the North leaving open water at the North Pole. Pole, where tectonic plates are pulling apart. The ridge is flanked CaSsepaian by deep ocean, surrounded by shallow shelves extending from the continents, which are dotted with islands. Most of these islands are connected by sea ice in winter, but the ice melts away in summer to leave a relatively small \u2013 and shrinking \u2013 area of ice around the North Pole. Black Lena Delta Six huge rivers Sea Mediterranean Sea pour fresh water A colder past Melting away into the Arctic Sea ice once extended The white area shows the E Ocean \u2013 the sea ice in September 2019. Mackenzie, Yukon, this far in summer. U Ob, Yenisei, Top of the world Kolyma, and the R Lena (seen here In 1958, the nuclear from space as it submarine USS Nautilus O flows into the made the first voyage Laptev sea). These across the North Pole P rivers make the underneath the pack ice. Arctic the least More recently, similar E salty of the nuclear submarines world\u2019s oceans. have been able to North Arctic islands surface through the Sea The ocean is dotted ice at the pole. with islands such as MRiiddg-Ae tlanti Novaya Zemlya, Moving waters Svalbard, the Queen OCE Elizabeth Islands, Polar winds blowing from the east drive an ocean current Baffin Island, and clockwise around the central Arctic Ocean, as well as the Greenland (left). cold Transpolar Drift current that diverges around Rocky and icebound, Greenland. Currents also flow in the opposite direction vegetation on these along continental shores. The currents carry sea ice across islands is sparse. the North Pole and south to warmer waters where it melts. c Cold current AN Icebergs Off Greenland, icebergs are formed from glaciers that have flowed from the land to the coast. In Baffin Bay icebergs drift south with the Labrador Current, down the Davis Strait and into the North Atlantic where they are a threat to shipping.","192 ocean maps ATLANTIC OCEAN 16,000 km (10,000 miles) \u2013 the length of the Mid-Atlantic Ridge, the longest mountain range on Earth. Shoreline breeders Baf n Greenland Greenland Rich marine life in the Bay Sea north Atlantic supports a Iceland host of seabirds like these Labrador Norwegian SBa puffins, which breed on Sea Iceland Sea North Sea rocky shores in spring. Basin Labrador Hudson jandegse ltieca Bay H A Basin FCrhaacrtluier-eGZibobnseMid-AtlanticPorcupine Grand Banks Plain T of Newfoundland RRieyk C MNEORRI OcAetalannotgiNsraepwhBfeorFaurRsanincidtdluargnedeZForancetAuzroerZeosnFEeMAraaPzasocldrtateesuiAn-iBrrzeiasocZareyosPnIRlbaeMieisnreaiadnBBeaiisryacaoyf Sargasso Sea A This calm sea is at the centre Hatteras Plain Sohm of a gyre. Water and debris Plain are swept towards it. Bermuda Gulf Canary of Sargasso Islands Mexico Sea M i d d l eT rAemn cehr i c a Yucatan Nares PlainKane Fracture Zone Cape Basin Verde Basin Caribbean Cape Verde Sea AT L A N T I CBarracuda Fracture Zone Plain O C E A NDemeraraVema Cape Fracture Zone Gambia Verde Islands Plain Gal\u00e1pagos Plain Doldrums Fracture Zone Islands Sierra Four ZonReoCmhaainnchFerLBaFecarotsaunicrneetuZreonZeone Tropical storms North Fracture The Gulf of Mexico and the P ePr uA- CCh iIl eFTIrCench O C E A N Ridge Fracture Zone Caribbean are regularly hit Pernambuco by hurricanes that brew up SOUT H Plain Ascension over the tropical Atlantic. MERI C Hurricane Dorian (seen from Fracture Zone space, above) caused huge Fracture Zone destruction when it swept west over coastlines and Saint islands in 2019. A A Brazil Ascension Island Atlantic Basin Bode Saint Helena Helena Santos Fracture Zone Plateau Rio Grande Rio GrandeMid Rise Tristan da Cunha Fracture Zone Argentine Gough Fracture Zone Giant river Basin Tristan da Vast amounts of fresh water and mud pour Cunha into the Atlantic Ocean from the River Argentine Plain Amazon, spreading out over 1.3 million sq km South Georgia (500,000 sq miles) of ocean. The river water Falkland dilutes the saltiness of the ocean and the mud Gough builds up to form huge, flat islands. Islands S cot i a S e a Island","2.5 cm (1 in) a year \u2013 the average rate at 305 km\/h (190 mph) \u2013 the maximum windspeed 193 which the Atlantic Ocean is getting wider. of the most powerful Atlantic hurricane on record. ocean data Atlantic Ocean ATLANTIC OCEAN Extending from the icy fringes of the Arctic to the Southern Ocean around Antarctica, the vast Area: 106,400,000 sq km (41,100,000 sq miles) Atlantic is the world\u2019s second-biggest ocean \u2013 and it is getting bigger every year. Average depth: 3,300 m (10,830 ft) The Atlantic Ocean originated as a rift that opened up through Deepest point: 8,605 m (28,230 ft) an ancient supercontinent some 180 million years ago, during the age of the dinosaurs. The ocean floor is still expanding from EUROPE Mediterranean Sea the rift, steadily pushing the Americas further away from One of six seas linked Europe and Africa. Molten rock from below Earth\u2019s crust has Black to the Atlantic, the risen up through the rift to form the volcanic Mid-Atlantic Ridge, Sea Mediterranean is which snakes north to south through the entire ocean. almost completely Mediterranean Sea surrounded by land. Swirling gyres AFRICA Ocean water swirls around the north and south Atlantic in huge current systems called \u201cgyres\u201d that flow clockwise in the north and anticlockwise in the south. They drive westward-flowing currents that carry warm water away from the tropics. Cold parts of gyres (shown here in blue) help to cool the tropics, while warm parts of gyres (red) carry heat to cooler regions. Water and floating debris are pushed towards the calm centres of the gyres. Guinea Gulf Gulf of Guinea The narrow arrows indicate the Basin of The shape of the gulf is direction of individual currents similar to the corresponding Guinea coastline of South America \u2013 Puerto Rico Trench evidence of the ancient AngolaRidge continental rift. There are only a few areas Basin where the ocean floor of the n Skeleton Coast Atlantic is being destroyed Walvis The cold Benguela Current in the Atlantic flows in deep ocean trenches. The north past southwest Africa, chilling the air over main site is the Puerto Rico Cape Basi the ocean. This causes fogs that strip the air of Trench, where the ocean floor moisture, creating the coastal Namib Desert and grinds beneath the edge of the the barren shores of what is called the Skeleton Caribbean Plate. This activity Coast. Here, the wrecks of ships that have run has fuelled the eruption of into rocks in the fog are strewn along the coast. volcanoes, which have formed the islands of the Lesser Antilles, such as Montserrat (right). Oceanic Iceland The Mid-Atlantic Ridge is made up of a chain of volcanoes under the water. In the far north an unusually active section called the Reykjanes Ridge breaks the ocean surface to form Iceland. The ridge passes through the middle of Iceland, dotting the landscape with active volcanoes. As a result, much of Iceland\u2019s landscape (left) is formed from dark basalt, a type of volcanic rock.","194 ocean maps INDIAN OCEAN 1 million sq km (386,000 sq miles) \u2013 the area of ocean floor covered by the gigantic Bengal Fan, to the south of the Ganges Delta. Suez Canal ASIA The Red Sea is a major shipping route, thanks to Himalayas the Suez Canal, which links its northwestern tip Red Sea PGeurlsfianQueeZnonFreactureGulf ofMOuRmrirdaagnye Bay of with the Mediterranean. Bengal Saudi Arabian The canal is 193 km Arabia Sea Andaman (120 miles) long, and Islands broad enough to allow Gulf of Aden Arabian GTuhlaf iolafnd the passage of ships Chagos-Laccadive Plateau Andaman up to 50 m (164 ft) wide. Basin Sri Lanka Coral islands C a sberg Ridge Sea The thousand-plus coral islands of the Maldives lie on the rocky ICA rl Maldives Ninetyeast Ridge ridge of the Chagos-Laccadive Plateau. Most of these are only Valley Somali Basin Ceylon EasRitdIgnediaman S a metre or two high, making Plain them vulnerable to rising sea u levels caused by climate change. m a t r AFR Chagos Trench Cocos a Basin Great Rift J Seychelles a a M v Comoros Mascarene ascarene Plateau Mid-Indian Mid-Indian Investigator RidgeChristmas Basin Basin Island MoCzhaanmnbielque INDIAN Madagascar Mauritius OCEAN R\u00e9union MPlaasicnarene Madagascar n Ridge Basin Perth Broken Ridge Basin Living fossil MMaNdoaazgataamslbcBaiqrauPesliaPntlaeateuauSouthwest India Ridg e The coelacanth is a type of fish FraDciatumreanZtoinnae believed to have been extinct South Crozet for 70 million years, until it was discovered living in the Mozambique Cape Africa Basin Southeast Channel in 1938. Fish of this Basin Southeast type were the ancestors of all Crozet land vertebrates. Agulhas Ocean Plateau Plateau Kerguelen PlKaetergauuelen Indian Agulhas Current Islands Indian The southward-flowing Agulhas Current Agulhas Ridge Basin Conrad Basin slams into storm waves off South Africa, creating giant, very dangerous Rise Southern waves up to 20 m (66 ft) high. Enderby Plain ocean data INDIAN OCEAN Area: 73,600,000 sq km (28,400,000 sq miles) Average depth: 3,890 m (12,760 ft) Deepest point: 7,450 m (24,440 ft) ANTARCTICA","110 The number of active volcanoes on Java, Sumatra, and nearby 1,192 The number of coral 195 islands, created by the tectonic activity of the Java Trench. islands in the Maldives. Indian Ocean East Philippine Lying to the south of Asia, the Indian Ocean is the China warmest of the world\u2019s five oceans. Its temperature has Sea dramatic effects on the climates of nearby countries. The open waters of tropical oceans usually have relatively little marine life, because the warm surface water does not mix with the nutrient-rich water below. But strong monsoon winds in the northern Indian Ocean drive currents that drag nutrients to the surface, fuelling the growth of plankton that support a wealth of fish and other life. River water flowing out of Asia also carries vast amounts of mineral-rich sediment into the Bay of Bengal, creating a rich marine ecosystem. South Ganges Delta China Sea Sulu SeaPACIFIC OCEAN Sediment eroded from the Himalayan RiEftast AfricanSeamountains is carried to the ocean by the Philippine Ganges River, where it forms the Ganges Celebes Delta (above). Lying above sea level, Borneo Sea Trench the delta is the top of the submarine Arabian Expanding seas Bengal Fan, a vast build-up of silt Peninsula that is so heavy it distorts the The floor of the Indian Ocean Earth\u2019s crust. Africa is expanding where tectonic plates in the Earth\u2019s crust are JSJaeaavvaa Sunda IndianRed Seapulling apart. Along the line of Shelf Ocean the rift a mid-ocean ridge has Banda formed. This ridge extends north into the Red Sea, where it is Trench Sea pushing Arabia away from Africa, making the Red Sea grow North Arafura wider every year. The Red Sea Shelf Rift is also linked to the East African Rift, which is ripping Australian Africa apart. Cuvier Basin Plateau The dotted line shows the location of the rifts AUSTRALIA Monsoon rain South In summer, hot, dry air over Australian the lands of Asia draws moist air from the Indian Ocean. Basin Huge rain clouds form, spilling torrential rain over the land Java Trench that often causes flooding The northeastern edge of the (pictured right). In winter, ocean floor is grinding beneath Asia, cool air sinks over Asia and creating the deep Java Trench. pushes dry air southwards, This is one of the world\u2019s most active reversing the wind system volcanic and earthquake zones, and causing droughts. creating volcanoes like Krakatoa (pictured above) and triggering the Cyclone chaos catastrophic 2004 Asian tsunami. The low-lying Ganges Cold frontier Delta is vulnerable to The cold waters of the Antarctic storm surges driven Circumpolar Current \u2013 the largest current by tropical cyclones that swirls around Antarctica \u2013 mark the that sweep north up southern boundary of the Indian Ocean. the funnel-shaped Bay of Bengal. In 2008, Cyclone Nargis caused catastrophic flooding in this way.","196 ocean maps PACIFIC OCEAN 1.6 million sq km (600,000 sq miles) \u2013 the size of the Great Pacific Garbage Patch, a patch of floating debris that is almost three times the size of France. Tropical typhoons Aleutian Trench Emperor Seamounts Bering Sea Gulf of The tropical Pacific This deep trench marks Alaska is regularly swept by where the ocean floor is Aleutian Trench huge revolving storms. plunging beneath Alaska. Known as typhoons or Chinook Mendocino Fracture tropical cyclones, they Kuril Trench Trough are the same as Atlantic hurricanes, and just as Northwest Murray Fracture devastating in their Paci c Basin impact. The most intense storm ever Trench Mid-Paci Hawaiian Ridge Molokai recorded was Typhoon Clarion Fracture Tip in October 1979, East with winds reaching up Mariana OCEAN to 305 km\/h (190 mph). Basin Mariana Trench The ocean floor here lies almost 11 km (7 miles) below the waves. c Seamounts Hawaiian Islands Mariana Mic Caroline ron e s i a Central Paci c Islands PACIFIC Melanesian Basin Me l Basin Papua New Guinea anes i a Line Islands Coral reefs Solomon n South Pacific shores are bordered by beautiful Islands esia coral reefs (see pp.98\u201399). The Great Barrier Reef \u2013 famous for its rich diversity of animal life \u2013 extends Coral Samoa along the coast of northeastern Australia for Sea 2,300 km (1,430 miles). Fiji Tahiti ocean data LouiSouthKermadec Trench ly Fiji o PACIFIC OCEAN Lord Howe P Basin Area: 141,120,000 sq km (54,500,000 sq miles) AUSTRALIA South West Average depth: 4,317 m (14,163 ft) Rise Paci c Basin Deepest point: 10,977 m (36,014 ft) Tasman sville Ridge Agassiz Pacific Ocean Sea New Menard Zealand Fracture Zone Eltanin The biggest and deepest ocean, the Pacific covers about Campbell a third of the world\u2019s total surface area, and extends nearly Plateau halfway around the globe. A N TA RC TI C A Larger than all the continents combined, and accounting for almost half of the total area of the world\u2019s oceans and seas, the Pacific is truly gigantic. Yet it was once even bigger \u2013 while other oceans, such as the Atlantic, are expanding, the Pacific is gradually getting smaller, carrying America closer to Australia, Japan, and China.","25,000 The number of islands in the tropical south 714 million cubic km (171 million cubic miles) \u2013 the approximate 197 Pacific, forming the realm of Oceania. volume of ocean water in the Pacific \u2013 half the world\u2019s total. NORTH Kelp forests Zone A M E R Extensive submerged forests of giant kelp \u2013 a type of seaweed (see Zone pp.74\u201375) \u2013 line the cooler coastal ICA waters of North and South America, Fracture Zone which are rich in nutrients. With Gulf of Califo fronds growing up to 50 m (164 ft) Zone rnia GMulefxoifco from the seabed to the surface, Clipperton Fracture Zone they are home to a wide variety M i dTdrl ee nAc of animals, including fish, sea lions, Galapagos Fracture Zone and sea otters. East Paci c Rise Pacific Ring of Fire The Pacific is shrinking because the ocean floor is being destroyed at the edges, where it is slipping beneath other plates making up Earth\u2019s crust. This process \u2013 called subduction \u2013 has created a ring of deep ocean trenches all around the outer edges of the Pacific from New Zealand to Chile. Along these subduction zones are at least 450 volcanoes, which surround the ocean and form the \u201cPacific Ring of Fire\u201d. m e r i c a h Guatemala Gal\u00e1pagos Islands Basin Although these volcanic islands lie on the equator, they are swept by Galapagos the cold waters of the Peru Current. Islands These waters are rich in nutrients that support plankton, fish, seabirds, and Marquesas Fracture ZoneEast Paci c Rise Peru other wildlife such as this seaweed- Basin eating Gal\u00e1pagos marine iguana. Easter Fracture Zone Hotspot volcanoes Easter Most volcanoes occur near plate boundaries. Island However, the ocean floor of the Pacific is also dotted with isolated volcanoes that have erupted over hotspots beneath Earth\u2019s crust. Hotspots are fixed spots in the mantle where magma is especially hot. Movement of the crust over these hotspots creates chains of volcanic islands and submerged seamounts. The longest, the Emperor Seamount Chain, which includes the Hawaiian Islands, stretches 6,000 km (3,730 miles). Fracture Zone Challenger Fracture Zone South East Black smoker Paci c Basin The East Pacific Rise is a fast-spreading mid-ocean ridge dotted with underwater Fracture Zone hot springs known as black smokers (see pp.64\u201365), which gush superheated, mineral-rich water into the cold, dark ocean depths. The smokers support amazing communities of organisms that get all their energy from the chemicals in the water, instead of from sunlight.","198 ocean maps SOUTHERN OCEAN 30 million cubic km (7.2 million cubic miles) \u2013 the volume of water contained in the Antarctic ice sheet. Volcanic islands WalvCisaRpiedgBe asin AFR The deepest point in the Mid-Atl Discovery Cape Rise Southern Ocean is the A TOLCAENATNI C a n t i c Rid Tablemount South Sandwich Trench. Here, one slab of ocean floor is grinding beneath another. The collision has created a chain of volcanic islands. Agulhas Plateau ge Agulhas SOUTH AMERICA South STarneSndowcuhtihch ER Atlantic-Indian Basin Georgia Argentine Ridge Basin ScoSteiaa S OWUe dPTdl aeHliln NO C E A N Prince Edward ScRotidg Maud Islands Rise Falkland Enderby Islands e ia Drake Passage Weddell Sea Rocky refuge Juan Ronne Ice Filchner The northernmost tip of Antarctica, Fern\u00e1ndez Shelf Ice Shelf known as the Antarctic Peninsula, thaws in summer. This allows it to Islands Larsen Berkner support breeding colonies of birds, Ice Shelf Island such as Ad\u00e9lie penguins, that cannot nest on the ice. Chile RiseBaPSaocuth Amery Ice Shelf Bellingshausen A N TA R C T I C A Sea South Pole eaisfitcsin AmuRniddsgeen Menard Fracture Zone Ross Ice Shelf East Paci c Amundsen Ross Sea Rise Sea PACIFIC Udintsev Southeast OCEAN Eltanin SOUTHERN O CEAN Pacific-Antarctic Ridge Ross Ice Shelf Fracture Indian-Antarctic The continental ice sheets of Antarctica Fracture extend over coastal seas to form deep ice Macquarie Ridge shelves. The vast Ross Ice Shelf covers Tasman 500,809 sq km (193,363 sq miles) \u2013 the Plateau size of France. Zone Campbell Tasmania Zone Plateau ocean data S o ut h w e st Lo Chatham Rise Tasman Pacific Basin uisville Ridge Basin SOUTHERN OCEAN Lord Howe Rise Area: 35,000,000 sq km (13,514,000 sq miles) New Zealand Average depth: 3,350 m (11,000 ft) Deepest point: 7,235 m (23,740 ft)","16,000 km (10,000 miles) \u2013 the distance that some Antarctic coastal seas are often deep because the Earth\u2019s crust 199 albatrosses can fly in a single journey. has been distorted by the colossal weight of the ice sheets. ICA Southern Ocean MozaRmidbgiqeueBNaastianl The Southern Ocean, which surrounds the frozen Antarctic continent, is the stormiest, iciest, most hostile Conrad PInladSteioaaunthRwidegset Crozet Islands ocean on Earth, yet it abounds with marine life. Rise Crozet The Crozet Islands and other sub- Crozet Antarctic isles are home to breeding Apart from the shores of Antarctica, the Southern Ocean has Islands albatrosses. The wandering no obvious boundaries. Its northern frontier is the Antarctic Mid \u2013 Indian Ridge albatross, pictured above, spends Convergence, where the cold Antarctic Circumpolar Current sinks Crozet most of its life in flight, riding beneath the warmer waters of the south Pacific, south Atlantic, uPlain Basin the storm-force Antarctic winds, and south Indian oceans. The boundary is not visible, but it is but it comes to land to nest. obvious to anyone heading south on a ship, as the temperature Davis Sea suddenly drops from about 6\u00b0C (43\u00b0F) to near freezing point. Kerguelen Plateau Kerguelen Island Food-rich waters Heard and Winter ice The Antarctic Circumpolar Current McDonald The extent of flows east around the continent. winter sea ice is At its inner boundary, close to Islands I N D I A N shown in grey. Antarctica itself, deep, nutrient- rich water is drawn to the surface OCEAN from near the ocean floor. The nutrients fuel the growth of clouds Ridge Broken Ridge of microscopic algae. These in turn feed vast pinkish swarms of krill \u2013 Basin the staple prey of penguins, dian crabeater seals, and baleen whales. Frozen ocean When the air over the Southern Ocean chills down with the onset of winter, the sea starts to freeze over. By September, sea ice covers some 18 million sq km (7 million sq miles) \u2013 more than the area of Antarctica itself. In spring the sea ice starts to melt away, shrinking to less than 2.6 million sq km (1 million sq miles) in February. Indian ast In e h t u ge So raLliraIanliaBAinghBtasin Rid SouGtrheaAtuAstust A Sea ice extent in September Sea ice extent in February AU R Giant icebergs Drowned continent Huge tabular (flat-topped) icebergs T break away from the Antarctic ice The continent of Antarctica lies shelves and drift with the currents. beneath vast ice sheets, up to 4 km S This one, known as iceberg D28, broke (2.5 miles) thick at their deepest away from the Amery Ice Shelf in parts. These continental ice sheets 2019. Seen here from space, it had an are made of fresh water \u2013 in fact area of 1,632 sq km (630 sq miles). they contain around 70 per cent of all the fresh water on Earth. Much of Antarctic Convergence the bedrock beneath lies below sea The white dotted line marks level, so if there was no ice large the boundary of the ocean areas of the continent would be at the Antarctic Convergence. underwater, as this map shows.","200 glossary Glossary ABDOMEN ATMOSPHERE BIVALVE CARAPACE In crustaceans and insects, the rear The air that surrounds Earth, which A type of mollusc, such as an oyster The hard upper shell of a turtle or part of the body. contains gases such as oxygen and or a mussel, that has a shell made of a crustacean such as a crab. carbon dioxide. up of two halves joined by a hinge. ADAPTATION CARBON DIOXIDE ATOLL BLOWHOLE The way an organism becomes A gas that forms a small part of the more suited to its environment A ring of coral reef that surrounds The nostril on the top of the head of atmosphere and is found in water in through evolution. a lagoon. a cetacean, through which it breathes dissolved form. Some living things, air at the ocean surface. such as algae and plants, can use it ALGAE BACTERIA to make food. BLUBBER Plant-like organisms that usually live Microscopic organisms that are made CARCASS in water and use energy from sunlight of only one cell. A thick layer of fat beneath the skin to make their own food. The largest of some marine mammals, including The dead body of an animal. algae are seaweeds, while the smallest BAITBALL whales and seals, that provides are part of the plankton. insulation in cold oceans. CARNIVORE A tightly packed ball of small fish ALGAL BLOOM swimming closely together as a BONY FISH An animal that eats other animals. defence against predators. A large concentration of algae in one A fish that has a skeleton made of CARTILAGE area. Algal blooms can be harmful BALEEN bone, rather than of cartilage. Around to other life. 90 per cent of all fish in the oceans A tough, springy material that in A mesh of bristly plates in the are classed as bony. some fish, such as sharks, forms the ANAL FIN mouths of some types of whale, skeleton instead of bone. These fish used for sieving and trapping tiny BRIDGE are known as cartilaginous fish. A fin on the belly of a fish, just in food particles from seawater. front of its tail, used for keeping the Of a ship, the area at the front from CAUDAL FIN fish stable as it swims. BEAK which the ship is steered. The fin that makes up a fish\u2019s tail. ANTENNAE In marine mammals, such as some whales and dolphins, a projecting BUOY CAY A pair of sense organs that can snout similar to the beak of a bird. detect movements and chemicals A floating marker anchored to the A low island made of coral sand. in the water. BELL seabed by a chain or cable. CELL AQUACULTURE The muscular, bag-like body of BUOYANCY a jellyfish. The smallest unit of life. Some The cultivation of fish and other The ability to float. organisms, such as bacteria, consist of marine species, usually for food. BIODIVERSITY just one cell. Larger forms of life may BYCATCH consist of trillions of different types of ARTHROPOD The variety of all living things cells that perform various functions. found on Earth or in a particular Fish and other marine life that are An invertebrate animal with an area, measured by numbers of caught accidentally in fishing nets CEPHALOPOD external skeleton and jointed legs. different species. cast to catch other species. Bycatch is often thrown dead or dying back An animal belonging to the group of BIOLUMINESCENCE into the sea. marine molluscs that includes squid, octopuses, and cuttlefish. Emitting a natural light. It is seen in CALF animals that live in the deep, dark CETACEAN zones of the ocean where sunlight The young of a whale, dolphin, or manatee. A whale, dolphin, or porpoise. cannot penetrate. CAMOUFLAGE CLIMATE The ability of an organism to blend The most common weather conditions in with its environment. in an area over a period of time. CLIMATE CHANGE The process of gradual change to Earth\u2019s climate due to human activity. COLONY A group of organisms living together. A colony of tiny organisms may work together to perform the functions of one creature, such as a salp or a siphonophore. These are known as colonial animals."]