Antarctican facts:
After centuries of speculation and exploration, Antarctica was finally discovered on January 27, 1820, by Estonian Admiral Thaddeus Von Bellingshausen, commanding a Russian voyage. Since then it has captivated explorers, scientists, and the public’s imaginations. Though what do people really know about Antarctica? Here are a few facts.
Geography:
Antarctica is the fifth largest continent, with an area of fourteen million square kilometres, compared with Europe’s ten million square kilometres and the USA’s nine million square kilometres. Containing a tenth of the Earth’s total landmass, Antarctica is twice as big as Australia, but if it were to lose its ice, East Antarctica would be Australiasized, while West Antarctica, comprised of the Peninsula and Marie Byrd Land, would be a series of islands. Ninety-eight percent of Antarctica is covered with ice; the remaining ice-free two percent (including the famed Dry Valleys) would be about the size of New Zealand. Most of the exposed rock is in the Trans-Antarctic Mountains or along sparse and narrow slivers of coast. Antarctica is surrounded by the fierce, wind-lashed, Southern Ocean, which extends from the 40th south parallel to the Antarctic Circle at 66 degrees South. South America is the closest continent at 1100km away while Australia and South Africa are 2500km and 4000km away, respectively. Antarctica is one lonely place.
East Antarctica is formed from old continental crust, heavily folded and metamorphosed. It rises steeply from the coast to the central plateau at over 4000m. The East Antarctic ice sheet was fully formed by at least fourteen million years ago and though there were fluctuations in temperature, the ice sheet has remained intact with no compete de-icing.
The 1200km-long West Antarctica from the Peninsula to the Trans-Antarctic Mountains constitutes 6.8 percent of Antarctica with an average elevation of 2000m. Marie Byrd Land averages 600m to1000m, with mountains peaking over 2000m, while the Peninsula, is part of an ancient Antarctic-Andean structure that ends near the Ellsworth Mountains. The Ellsworth Mountains at the base of the Peninsula are part of a separate structure to the Trans-Antarctic Mountain system and has some limited bare ground as does the Peninsula, the bare ground existing due to the disappearing icecap. The West Antarctic ice sheet was fully formed by at least five million years ago. There is no suggestion of any period where there was a complete ice sheet disappearance.
Climatic processes:
The strong winds around Antarctica circulate in a westerly direction, due to the southern latitude’s low temperature and pressure compared to the equator’s high temperature and pressure, which combined with the rotation of the Earth, provides the wind system. The temperatures of East Antarctica can reach 89 degrees Celsius, the strong katabatic (downward flowing) winds affecting the Antarctic plateau. But the katabatic winds are lessened on the Peninsula when these winds interact with eastbound cyclonic winds bringing warm, moist air, and precipitation from the sea. These cyclonic storms frequent the Peninsula, as they are further north and in the path of the circumpolar winds.
Ocean circulation close to the continent is from the east, but in the Furious Fifties and Roaring Forties they shift to come in from the west, creating the Antarctic Divergence, where the two currents sweep away from another, which can actually be seen as a physical boundary in the water. Carrying ten percent of the world’s oceans, connecting the Atlantic, Pacific and Indian oceans, the circumpolar current’s rate is four times that of the Gulf Stream. The storminess of the Southern Ocean is due to a bottleneck effect created by Tierra del Fuego and the Antarctic where the Atlantic, Pacific and Southern Oceans combine. Two thousand miles of ocean are suddenly compressed into a much shallower, 600-mile wide area, with winds forced southward via the Andes mountain range. The prevailing weather system then moves from west to east. In fact, Cape Horn earned the name wallapak wellek, meaning ‘evil point’ from the Yamana Indians on Tierra del Fuego due to its storminess.
Climatic regions and Temperatures:
Four general climatic regions have been identified, including the interior Antarctic plateau (East Antarctica plateau), the Antarctic slope, the Antarctic Coast and Maritime Antarctic (west Antarctic Peninsula, its islands, and the South Sandwich and South Shetland Islands). The Southern and Eastern parts of the Peninsula are completely ice-bound being 4 C to 6 C colder and having stronger winds similar to the East Antarctic coast.
The Peninsula receives more sunlight and daylight hours, and sea temperatures are higher even in winter. And because it is mountainous, it disrupts warm, moist air from the northwest garnering the Peninsula the highest precipitation rate for all of Antarctica with more than 1000mm per annum on the Peninsula west coast. The winds cause snowdrifts, sleet, and even rain with temperatures sometimes rising above freezing in the summer. On the Peninsula and adjacent islands in the winter, temperatures can range from 15C to +5C, while in the summer rise to 0C to 10C. The sub-Antarctic in summer and winter can be warmer by another 5C and mean annual temperatures on coastal Antarctica can be -10C
Zoological and Botanical:
Vertical ocean circulation from the Antarctic Bottom, consisting of water up-welling and sinking brings warmer water to the ocean top, which helps to cool the air and also produce nutrients for surface-dwelling organisms. This is important in Antarctica for the food chain in the Southern Ocean is rich with algae blooming after the winter, bringing in phytoplankton and zoo-plankton which nourishes krill, fish, seal and whales. Penguins, sea birds and small insects make for some of the land animals.
Invertebrates include collembola, mites, rotifers, protozoa, tardigrades, nematodes and others in Antarctica, with 25 mites species and 7 collembola species in Maritime Antarctica, the largest of which is only 5mm. These invertebrates in turn, forage on bacteria, fungi or algae. In modern times, reindeer, cats, and rats have been introduced to the Sub-Antarctic islands, but have had a rather negative effect on native species.
Botanically, there is not much. Antarctica has the coldest and driest climate in the world due to locked up water, resulting in very low humidity and precipitation, causing the soil-forming process (weathering, etc) to be reduced. Moisture plays an important role over temperature so in order to survive plants may choose anti-dehydration traits over cold resistance, with plant growth reflecting areas of moisture rather than warmth. As Antarctica was covered by ice by the Pleistocene era, any later re-colonisation by plant life had either to take place from existing plant expansion on limited unfrozen land or were imported from the surrounding continents by birds, wind or ocean currents.
Cryptogams make up one group of plants with 350 to 400 species of lichens, 360 species of algae, 9 Genera of liverworts, 28 macro fungi, 75 species of fungi, and 85 mosses most of which grow in the continental or maritime zones, some in both. But there are only two flowering plants on the Peninsula, the Antarctic hair grass and Antarctic Pearlwort or the carnation in the maritime zone. Compared to the fifty species of vascular plants on South Georgia Island this is still paltry when compared to the eighty thousand vascular plant species in the Amazon. Of course the higher north one goes, the diversity of faunal and floral species increases, as does the productivity of the soil. So at 65 degree South, where temperatures range from 0C midsummer to around 15C in the winter there can be a carpeting effect of lichens and mosses in more sheltered areas.
Antarctica is a fascinating place to contemplate and is on many an adventurous tourist’s list of pilgrimage, but tourism, climate change, and possible future industrial processes (mining) could spoil our last pristine continent.
Sources:
Argod, R. 2004. Out of Antarctica: Reflections on the Origin of Peoples. London: Richmond Editions.
Campbell, I.B. & Claridge, G.G.C. 1987. Antarctica: Soils, Weathering Processes and Environment. Amsterdam: Elsevier.
Crossley, L. 2000. Explore Antarctica. Cambridge: Cambridge University Press.
FlemAth, R & FlemAth, R. 1995. When The Sky Fell: In Search of Atlantis. London: BCA.
Hansom, J.D. & Gordon, J.E. 1998. Antarctic Environments and Resources -A Geographical Perspective. New York: Addison Wesley Longman, Ltd.
McLeod, L. (ed.) 2002. Savage Planet: Cape Horn. Manchester: Granada, 16-17.
Press, F. and Siever, R. 1986. Earth. New York: W.H. Freeman and Company, 292.
Pyne. S.J. 2003. The Ice. London: Weidenfeld & Nicolson.
Rubin, J. 2000. Lonely Planet: Antarctica. London: Lonely Planet Publications Pty Ltd.
