McDonald and Heard Islands - Biophysical processes
McDonald and Heard Islands are located halfway between Australia and South Africa in the Southern Ocean, at approximately 53°S 73°30’E. The islands are approximately 4000 kilometres southwest of Western Australia, 4700 kilometres southeast of Africa and 1000 kilometres north of Antarctica.
Heard Island is the largest in the group of islands at 368 square kilometres. The islands are some of the most remote places in the world.
The subantarctic islands are volcanically active, and allow for the study of geomorphic processes and glacial dynamics. Heard Island has experienced volcanic activity and fresh lava flows in the last few decades. This activity is continuing to shape the island including increasing its size and elevation. As a result of volcanic activity all vegetation on the island has been lost.
Heard Island and the McDonald Islands are located south of the Antarctic Convergence. The Antarctic Convergence is a marine zone where cold waters of the Antarctic sink under the lightly warmer waters of the subantarctic.
Heard Island is considered to be a biological hotspot. There are large colonies of penguins and petrels, and harems of fur seals and elephant seals. There are also high numbers of seabirds and marine mammals.
Due to the diversity of landscapes on the islands a range of different vegetation communities can be found. In the tundra areas vegetation is minimal and includes low shrubs, mosses and liverworts.
The islands are part of the Southern Indian Ocean Islands Tundra ecoregion. The mid-latitude location of the islands in the Southern Ocean is south of the Antarctic Polar Front. This is an area of strong, persistent westerly winds, and associated with a deep low pressure system. East moving depressions move across the islands throughout the year. This results in strong regional strong, westerly winds, frequent precipitation, and low seasonal and daily temperature ranges.
- relatively low-lying
- free from ice
- more stable weather than Heard Island
- Monthly average temperatures range from 0.0° to 4.2°C, with an average daily range of 3.7 to 5.2°C in summer and −0.8 to 0.3°C in winter.
- annual precipitation at sea level - 1.3 to 1.9 m
- high relative humidity
- persistent cloud cover and often-spectacular cloud formulations
- predominantly westerly and persistently strong winds
- perennial ice cover and mountains impact on local climate. Big Ben the island’s largest mountain has orographic affects on precipitation, snow accumulation winds and cloud cover.
Conduct research on the Heard and McDonald Islands. Create a profile of the islands and the biophysical processes that occur there. Refer to the processes that occur in each of the four spheres: atmosphere, lithosphere, biosphere and hydrosphere.
For a more detail, view:
UNESCO Heard and McDonald Islands
Australia's Heard Island: A mysterious land of fire and ice
Heard and McDonald Islands - FAQs
World Heritage Places - Heard and McDonald Islands