Water, which comprises of two-thirds of the planet earth, is divided into five oceans. The southernmost division of the world ocean that encircles Antarctica (south of 60 degree S latitude) is called Antarctic Ocean. It is the fourth largest ocean after Pacific, Atlantic and Indian Ocean. The Arctic Ocean is the only ocean that is smaller than Antarctic Ocean. The Antarctic Ocean has many names like Southern Ocean, The great Southern Ocean, South Polar Ocean, Austral Ocean etc.
The geography of the Antarctic Ocean is very interesting. Antarctic Ocean was formed when the continents of South America and Antarctica moved apart, that opened up the Drake Passage. This happened 30 million years ago. But this long period still makes Antarctic Ocean the youngest of all the oceans. The Antarctic Ocean is flanked by Pacific, Atlantic and Indian Oceans in the north, unlike other oceans which are surrounded by landmass in the north. This also poses a huge difficulty of distinguishing the oceans. In fact the only reason for considering them as different Oceans is the fact that the water of the Antarctic Ocean is very different. The flow of water causes a current called Antarctic Circumpolar current which circulates the water around it very rapidly.
The Antarctic Ocean is relatively shallow. The average depth varies between 4000-5000 m. The South Sandwich Trench is the deepest point in this ocean and is about 7236 m deep. There are many geographical subdivisions such as bays, straits, channels and so on. The temperatures fluctuate from 272 – 283 K. It is cold throughout the year. Moreover, there are cyclonic storms that travel eastwards that become very turbulent due to the temperature fluctuations between the water and ice.
There Southern Ocean is rich in resources and biodiversity. To mention a few, it has huge possibly giant gas and oil fields. This is mainly concentrated on the continental margin. The gravity separation during the sedimentary process has been speculated to be a reason for the possibly good deposits of gold and many such valuable metals. Manganese nodules are also suspected of being present in the depths of the ocean. Apart from these, the icebergs that form in the Antarctic Ocean are a very good resource of freshwater. But the resource has not been tapped, though few proposals have been made to tow the icebergs to the more dry regions of north like Australia.
The flora and fauna of the Antarctic Ocean is very amusing and diverse. Since the ocean has a low temperature and huge exposure, the animals found are extremophiles. This means they have to adjust to extreme climates. The animals rely on the phytoplankton present in the ocean, either directly or indirectly for food. This is obvious because Antarctica is a cold desert with sparse vegetation. The animals found include, blue whales, orcas, fur seals and not to forget penguins. Penguins are the major attractions in the Antarctic region. There are different species of penguins present here that includes, gentoo penguins, king penguins, chinstrap penguins and so on. Rock hopper penguin which is known for its beauty (characteristic feathers around the eyes that give them features that are similar to long eyelashes) is also found there. The important species of seals found here are Antarctic fur seal, Antarctic krill, leopard seals, Weddell seals etc. As one goes to the depths of the ocean, near the sea floor, there are diverse and dense benthic population with about 1, 50,000 animals per square meter or 10.8 sq. ft. The deep sea floor is the same all around the Antarctic, so there are hundreds of species that are similar, all over the region as in the mainland. This gives a large distribution of a unique collection of animals. Deep sea gigantism is a known trait among the animals here.
The birds include albatrosses, sues, gulls, petrels and terns. There are more than 100 million birds that visit the rocky shores of Antarctica for nesting purposes. The insectivorous South Georgia Pipit is common to South Georgia and some minor surrounding islands. Freshwater ducks live in South Georgia and the Kerguelen Islands.
The variety of fish in this ocean is pretty less as compared to others. The white-blooded fish also called the Channichthyidae family are only found in the Antarctic Ocean. They are called so because they lack hemoglobin that makes their blood white. The Antarctic toothfish breeds very close to the mainland of Antarctic, but the Patagonian toothfish dwells in the comparatively warmer waters farther away. Due to this reduced water temperatures around, the Antarctic toothfish has antifreeze proteins in its tissues and blood. Toothfish are commercially very often fished, but sadly, illegal overfishing has reduced their numbers significantly.
There are many mammals in the Antarctic Ocean. Mainly it is the pinnipes species, commonly known as seals. Out of this, the largest is the elephant seal that can be up to 4000 kg in weight. The sizes are huge. The smallest seal is the Antarctic fur seal which again weighs 150 kg. The seals generally live on sea ice except the species mentioned about that ice in the north of the ice. Ross seals and leopard seals are independent creatures, while others stay in a group. The whales are the other class of mammals that are found here. There are 10 cetacean species, six baleen species and four toothed whales present in the Southern Oceans. The largest of them is definitely the blue whale that weighs up to 84 kg. Many of them are migratory and travel to the tropical regions to escape from the Antarctic winters.
The crustaceans present are mainly krill that are free-swimming crustaceans. With a biomass of around 500 million the Antarctic Krill is one of the most abundant species on earth. They move as a swarm with each tiny individual about 6 c in length and weight about 1 gram. As they move together they produce an illusion of red water. An amusing feature of the krill is that during the winters when the food is very scarce they can turn back to their smaller juvenile stage, using their own body as nutrition. Slow moving sea spiders are also common crustaceans here.
There are many invertebrates, the major class being the mollusks. They include the sea urchins, giant squid, scalps and sponges. Sponges are indicators of environmental pollution and are used by environmentalists to detect pollution and global warming.
The environmental issue in the Antarctic is a hot and sensitive topic. The main issue is global warming caused by the ozone hole above the Antarctic. It has permanent effects such as reduced productivity of phytoplankton that reduces the marine population to 15%. Apart from this it also damages the DNA of some fish. The environmental issues due to illegal, unreported and unregulated fishing is also significantly rising. This has led to many international agreements. Some of the recent agreements that came into effect are; The prohibition of commercial whaling south of 40 degrees south (By Southern Ocean Whale Sanctuary of International whaling commission), Convection for the conservation of the Antarctic Seals (As a part of Antarctic Treaty System), Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR) again as a part of the Antarctic Treaty System.
Then there is prohibition for the exploitation of mineral resources to the south of Antarctic Convergence. All these new pacts and agreements have been seen to have a positive effect in the issue but for long term benefits, many other steps ought to be taken.
Due to the rich marine life in the region there it is necessary that you preserve them and save them from extinction. Some of the facts like significant climatic changes, ocean acidification and fishing have greatly effected the marine population on this ocean. Large reserves created have provided a home to the marine species and have helped them adapt to the changes in the environment. Reserves have a great role in improving the environment and the ocean health bounded by it. So, more reserves are to be built to keep the marine life intact and to keep them from extinction.
The number of tourists visiting Antarctica has increased over the years and this has led to the introduction of alien species in the environment, meddling with vegetation and disturbing of the wildlife in the area. If this continues, it may threaten the peaceful and natural environment of Antarctica and its ocean. Bioprospecting can also effect the environment adversely and threaten some of the species. By keeping a control on tourism, fishing, mining and bioprospecting, you can prevent some potential damages to Antarctic Ocean and keep it and the surrounding oceans intact and safe from depletion. Awareness about the ocean and the ocean life must be created among the people. By taking the correct measures and making people aware about the importance of ocean and the marine life in it, you can preserve this ocean for the future generation and make the world a better place to live in.