Introduction
Antarctica is Earth’s southernmost continent, encapsulating the South Pole. It is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14.0 million km2 (5.4 million sq mi), it is the fifth-largest continent in area after Asia, Africa, North America, and South America. For comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages at least 1 mile (1.6 km) in thickness. Antarctica is the coldest, windiest and driest continent. Since all but 2.4% of Antarctica is covered by ice that averages 2,160 meters thick, it is also the highest continent.
Antarctica is about 14 million square kilometers in area, which is about the size of the contiguous 48 U.S. states plus about half of Mexico. The continent surrounds the South Pole and is cut off from all other continents by the southern parts of the Atlantic, Pacific, and Indian Oceans — which together are called the Southern Ocean.
|
Climate
The climate of Antarctica is the coldest on the whole of Earth. Antarctica has the lowest naturally occurring temperature ever recorded on the ground on Earth: −89.2 °C (−128.6 °F) at Vostok Station. It is also extremely dry (technically a desert), averaging 166 mm (6.5 in) of precipitation per year. Even so, on most parts of the continent the snow rarely melts and is eventually compressed to become the glacial ice that makes up the ice sheet. Weather fronts rarely penetrate far into the continent. Most of Antarctica has an ice cap climate (Köppen EF) with very cold; generally extremely dry weather throughout the year and no month averaging above 0 °C (32 °F).
The Research paper on Civil War Southern South Union
American Civil War- Secession American Civil War- Secession Essay, Research Paper A frequently, and sometimes hotly, discussed subject; the outcome of the American Civil War has fascinated historians for generations. Some argue that the North? s economic advantages proved too much for the South, others that Southern strategy was faulty, offensive when it should have been defensive, and vice-versa. ...
Some fringe coastal areas have a polar climate (Köppen ET) with a short summer averaging above freezing, and much higher precipitation.
Precipitation
Almost all Antarctic precipitation falls as snow. Note that the quoted precipitation is a measure of its equivalence to water, rather than being the actual depth of snow. The air in Antarctica is also very dry. The low temperatures result in a very low absolute humidity, which means that dry skin and cracked lips are a continual problem for scientists and expeditioners working in the continent.
Weather condition classification
The weather in Antarctica can be highly variable, and the weather conditions can often change dramatically in short periods of time. There are three classifications for describing weather conditions in Antarctica. At least one of the following criteria must be met for each category.
Condition 1
Wind speed over 55 knots (60 miles per hour)
Visibility less than 100 feet (30 meters)
Wind chill below −100 °F (−73 °C)
Description: Dangerous conditions; outside travel is not permitted.
Condition 2
Wind speed of 48 to 55 knots (55 to 63 miles per hour)
Visibility 1/4 of a mile to 100 feet (402 to 30 meters)
Wind chill of −75 °F (−60 °C) to −100 °F (−73 °C)
Description: Unpleasant conditions; outside travel is permitted but not recommended.
Condition 3
Wind speed below 48 knots (55 miles per hour)
Visibility greater than 1/4 of a mile (402 meters)
Wind chill above −75 °F (−60 °C)
Description: Pleasant conditions; all outside travel is permitted.
Natural vegetation
The majority of the Antarctic continent is covered by permanent ice and snow leaving less than 1% available for colonization by plants. Most of this ice and snow-free land is found along the Antarctic Peninsula, its associated islands and in coastal regions around the edge of the rest of the Antarctic continent. Even in the most inhospitable ice-free habitats, such as inland mountains and nunataks, life can still be found.
The Research paper on Need of a Strengthened Species Act
There lived a bird called Passenger Pigeon in North America. A century ago people could see them in thousands or even in millions. Sadly, there are very few of them left today. The species called passenger pigeons was becaming extinct like many other species. Obviously, there were no laws to protect endangered species, resulting in the large scale destruction of the native habitat. Providing ...
There are no trees or shrubs, and only two species of flowering plants, Antarctic hair grass and Antarctic pearlwort are found, occurring on the South Orkney Islands, the South Shetland Islands and along the western Antarctic Peninsula. The vegetation is predominantly made up of lower plant groups (mosses, liverworts, lichens and fungi) which are specially adapted to surviving in extreme environments, in particular, tolerating low temperatures and dehydration. There are, in total, around 100 species of mosses, 25 species of liverworts, and 300 to 400 species of lichens and 20-odd species of macro-fungi. The greatest diversity of species is found along the western side of the Antarctic Peninsula where the climate is generally warmer and wetter than elsewhere in the Antarctic continent. Certain species of moss and lichen, however, have a widespread distribution and others specialize in surviving in very extreme conditions.
Wildlife
Penguins are the most common birds in the Antarctic. Living in colonies with populations larger than some cities, and surviving in the harshest of conditions, it is no wonder that penguins are seen as the emblem of Antarctica. However, of the 17 different species of penguin, only two (emperor and Adélie) make the Antarctic continent their true home, although others (chinstrap, gentoo and macaroni) breed on the northern tip of the Antarctic Peninsula, where conditions are less harsh. King penguins only breed on the warmer more northerly subantarctic islands. One species, the Galapagos penguin, even lives on the equator. The real home of all penguins is the cooler waters of the Southern Hemisphere.
Whales and seals are the two groups of marine mammals to be found in the Southern Ocean where they are an important part of the marine ecosystem.
Whales and seals of the Southern Ocean have been severely exploited by man in the past, but are now mostly protected. Some seals and whales have had dramatic population increases in recent decades, though others remain greatly reduced compared to pre-hunting levels. The removal of millions of krill-eating whales and seals had a marked effect on the Antarctic marine ecosystem, and it may be centuries before a new equilibrium is reached. There are two natural groups of whales — toothed and baleen. As their name implies, toothed whales have teeth; they mostly eat squid and fish, and take their prey one at a time. The largest toothed whale is the sperm whale (Physeter macrocephalus) of Moby Dick fame, and the group includes more than 60 other species, varying in size down to porpoises, one thousand of which would equal the body weight of a single sperm whale.
The Essay on Seals Diet Consist Of The Antarctic Silverfish Penguins Fish Prey
Surviving in the Ross Sea Emperor penguins and Weddell seals are the only marine predators that breath air and live year round in Antarctica Ross Sea. How these two animals are able to live among each other when there diets, hunting depths and area distribution are shared is the question. Ross Sea is called home by six emperor penguin colonies, approximately 180, 000 birds, and about 50, 000 ...
There are also two natural groups of seals — true seals and eared seals, the latter comprising fur seals and sea-lions. In fact all seals have ears, but ‘eared’ seals differ in having a small external ear rather than just a small aperture on the side of the head. Depending on species, seals feed on fish and squid and/or krill. The leopard seal (Hydrurga leptonyx) is also a predator of penguins and other seals. Thick layers of blubber beneath the skin of both whales and seals, act as a food reserve and insulation. All Antarctic seals also have a layer of fur, giving additional insulation when they are hauled out on land or ice.
Seals leave the water to breed rest and moult. Of the six Antarctic species, four are ice habitat specialists, breeding on the sea ice in spring. Leopard (Hydrurga leptonyx) and Ross seals (Ommatophoca rossii) tend to be solitary, whereas Weddell (Leptonychotes weddellii) and Crab eater seals (Lobodon carcinophagus) form loose breeding aggregations.
Leopard seal
Ross seal
Weddell seal
Fish and cephalopods (squid and octopus) in the Antarctic are important components of the benthic and pelagic marine ecosystems. They are major prey for higher predators, including toothed whales, seals and seabirds.
The Antarctic fish fauna is unusual in being dominated by the radiation of small number of groups. The most striking radiation is that of the so-called Antarctic cods (not related to true cods) the Notothenioids, which dominate the continental shelves. However in deeper waters there are also significant radiations of snail-fishes (Liparidae) and eel-pouts (Zoarcidae).
The Term Paper on Fish Farming
Fish farming is the principal form of aquaculture, while other methods may fall under mariculture. Fish farming involves raising fish commercially in tanks or enclosures, usually for food. A facility that releases young (juvenile) fish into the wild for recreational fishing or to supplement a species’ natural numbers is generally referred to as a fish hatchery. Worldwide, the most important ...
The Antarctic fish fauna contains the unique vertebrate group the Channichyidae or ice fish (so called because of their pale coloration).
These fish are the only group of vertebrates which have no red blood pigment (haemoglobin).
Oxygen is transported instead in solution in the blood plasma. The mackerel ice fish (Champsocephalus gunnari) is important prey for Antarctic fur seals, and is the subject of a closely regulated commercial fishery.
Cods Notothenioids
The squid range in size from the small (15 cm) Brachioteuthis to the enormous (4 m) Mesonychoteuthis, which has large hooks, as well as suckers, on its arms and tentacles for capturing prey. The octopuses are less well known and despite the fact that they are very common, there are undoubtedly many species in Antarctic benthic ecosystems which are currently unknown to science.
Large fisheries for squid occur in waters adjacent to the Antarctic. Commercially exploitable squid live in Antarctic waters and exploratory fishing for them has already taken place. If full scale fishing develops, it will require management under precautionary principles by CCAMLR (Commission for the Conservation of Antarctic Marine Living Resources), because of the risk to dependent predators.
