The island of South Georgia as seen from The Copernicus Sentinel-2 mission. (2018)
South Georgia Island (54°15′ S) is 104 mi (167 km) long and roughly 25 mi (37 km) and, as a fragment of continental crust on the Scotia Plate, is composed of gneiss and schist. Eleven peaks, the highest of which rises to 6,500 ft (2,000 m), form its backbone and may be extensions of the Andes. Most of the island is ice-covered, but the surrounding sea is usually free of pack ice during the winter. Alpine glaciers which once extended to the ocean are now rapidly receding. On the north coast, in sheltered bays, low-lying areas are snow-free in summer.
South Georgia lies below the Polar Front, a position that causes it to have a more antarctic climate that its latitude would suggest. It is cold, cloudy, and windy, and the weather is highly variable, even from hour to hour. Katabatic winds may descend northeastern slopes with little warning. Snow can fall at any time of the year. Average annual precipitation on King Edward Point near Grytviken is 63 in (160 cm). Recorded temperatures there range from -2°F (-19.4°C) to 79°F (+26.3°C).
South Georgia and the islands of the Scotia Arc lie within the Antarctic Botanical Zone, a region of low terrestrial biodiversity. Plant life is similar to that to Tierra del Fuego and southern Patagonia. Tussac grass, mosses, and lichens dominate ice-free areas. Breeding King, Macaroni, and Gentoo Penguins, Black-browed and Wandering albatrosses, and Giant Petrels are abundant and attest to the richness of the marine ecosystem offshore. On Bird Island, off the northwest tip of South Georgia, where rats were never introduced, burrowing petrels and prions occur in large numbers. That island boasts one of the densest concentrations of breeding sea birds and seals in the world, while St. Andrews Bay on the east coast of South Georgia is iconic for its huge populations of King Penguins and great numbers of elephant and fur seals. The endemic South Georgia Pipit is the only songbird in the Antarctic region. There are no native terrestrial mammals.
House mice, brown rats, and reindeer were introduced to South Georgia during the era of whaling and sealing. Reindeer have been successfully eradicated, and several inter-glacial valleys have been rid of rats. Reindeer overgrazed native grasslands of tussac grass and greater burnet, which have since been replaced with annual meadow grass. Today the island has no permanent human settlers.
Snow- and ice-covered peaks form the backbone of South Georgia Island.
King Penguins and Elephant Seals are the main attractions.
Thousands of King Penguins nest at Salisbury Plain. The fuzzy brown chicks cluster in large creches on slopes above the coast.
Male elephant seal with several females and young hauled out on beach.
Away from the trampled coastal haulouts of seals and congregations of penguins, the vegetation is a grassland interspersed with bogs and small ponds.
Native fescue grasses and mosses cover some lower slopes. Several forbs including Antarctic pearlwort grow as low mats or cushions.
Macaroni Penguins nest high in the tussac grassland.
South Georgia Pipit (Anthus antarcticus) is endemic to South Georgia and the only songbird in the Antarctic. Its presence is most apparent from its song while in flight.
Giant Petrels squabble over the carcass of an elephant seal pup which probably died of avian flu. The smaller birds are Cape Petrels.
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Sources: Burton, Robert and John Croxall. 2012. A Field Guide to the Wildlife of South Georgia. South Georgia Heritage Press.Princeton, NJ, Princeton University Press. Quinn, Joyce A. 2008. Arctic and Alpine Biomes. Greenwood Guides to the Biomes of the World. Westport, MA,
Greenwood Press.
