Antarctic System Science

Aitcho Island

The first stop of the expedition was at Aitcho Island, which is part of the South Shetland Island group. The island group runs 280 miles N to S and are 100 miles west of the Antarctic Peninsula. William Smith first discovered the Shetland Islands in 1819 when he was blown off course while going around Cape Horn. The islands were originally called “H.O. Islands” after the Admiralty Hydrographic Office who mapped the island group in 1936. The name was later changed to “Aitcho Island,” a phonetic spelling.
	Aitcho Island is where our first encounter with penguins took place. Pictured here is a gentoo penguin (Pygoscelis papua). There are 17 species of penguin, of which 7 are commonplace in the Antarctic region. Penguins are flightless seabirds, and spend most of their time fishing at sea and only come on to land to breed and rear their young. They are highly adapted to the Antarctic system and their lives in the water. Their wings are very rigid and help them to swim. Unlike otherbirds whose bodies are made to be light in order to fly, penguins need the added weight to counteract bouyancy and dive in search of food.
Penguins, like this chinstrap, (Pygoscelis antarctica) rely on krill, the keystone species of the Antarctic system, as their main source of food. Some penguins may also feed on fish and squid. While in the water penguins usually dive in search of food for between 5-7 minutes and usually go as deep as 100 meters. The emporer penguin (Aptenodytes forsteri), which is the largest of the penguins can dive for 18 minutes and go as deep as 630 meters.
	During the summer months when penguins leave the water, they make their nests out of small stones. The nests are constantly being maintained by the birds, and the partner not sitting on the nest often goes to collect pebbles from adjacent nests to add to his/her nest. The real job of the parent that is not on the nest is to go and feed, especially when the young are born and can not yet enter the water. Penguins nest in colonies that range in size from a few pairs to over a million birds!
Further exploration of the island led us to a group of Southern elephant seals (Mirounga leonina) that were congregating near the shore to molt. This seal is the largest seal and the males can grow to be 20 feet long and weigh 4 tons while females average 12 feet and weigh 1 ton. When males reach maturity, they form the distinctive enlarged nose. They inflate the proboscis (inflatable sac) that is contained within the nose during the breeding season to lure females in order to breed. Males also fight both for play and for the right to breed. Scars from previous encounters are often visible on the seal. The Southern elephant seal is also the deepest diving seal, and can dive to 3,300 feet for over 30 minutes. During the time spent beneath the surface, the seal hunts for krill, squid and fish. One mature male usually has a harem of females that he services during the breeding season. The male will viciously defend the females and their offspring. Males who were not successful during the breeding season will sometimes hang around a successful male and his harem trying to fornicate with the females in hopes that he will have offspring. They go about this very stealthily, trying not to attract the attention of the bull. These seals are referred to as “sneaky fuckers.”
	The brown skua (Catharacta lonnbergi) is another bird that spends the summer breeding season in the Antarctic. Skuas are very opportunistic birds and aggressive birds. They often steal penguin eggs or kill small chicks. They have also been found to take milk from nursing elephant seals. They were gliding over the penguin colonies in search of abandoned eggs or exposed chicks. Several times they flew away with an egg in their mouth.
Although Antarctica is covered by an ice sheet except for 2.4 per cent of its 14 million square kilometers, there are some amazing geological features which appear along the exposed coastlines. Given the exposure of this rock, the snow had been scoured away from its base. This created prime nesting spots for penguins who were seen nesting all around the spire.
	The first thought that most people have about Antarctica is ice. There is sure an abundance of ice, and more and more is being learned every year. Cold temperatures have led to accumulations of ice on the continent for millions of years. The thickest portion of the ice is approximately 15,669 feet (4,776 meters) thick. The average coverage is 7,086 feet (2,160 meters) thick. The ice coverage of Antarctica comprises 90 percent of the the world's ice and 70 percent of the fresh water.