Icy ecosystems – key terms
Discovering Antarctica’s fragile frozen secrets
Antarctica is the coldest, driest, windiest and highest continent on Earth. What makes the frozen continent so valuable to scientists and vulnerable to human contact?
This resource provides explanations of the key concepts encountered when exploring this icy ecosystems – the ‘basics’ that every student should understand.
Antarctic food chain
A succession of organisms in an ecological community that constitutes a continuation of food energy from one organism to another as each consumes a lower member and, in turn, is preyed upon by a higher member. The Antarctic food chain is relatively simple, with fewer different species, but greater numbers of them.
Ecosystem Antarctica
The ecological community together with its environment, functioning as a unit that is roughly centered on the South Pole and surrounded by an ocean consisting of the southern parts of the Atlantic, Pacific and Indian oceans. This system can be organised into a marine and terrestrial ecosystem.
Ice/land ratio in Antarctica
During the winter, the size of Antarctica doubles as the surrounding sea water freezes, effectively blocking heat transfer from the warmer surrounding ocean. Antarctica has a higher average elevation than any other continent on Earth, which results in even colder temperatures.
Past climates
Earth's climate has been changing for billions of years – warming and cooling many times long before humans were around. Sediments and fossils deposited millions of years ago provide a record of ancient environments. Layers of mud and sand record seasonal changes, and tree rings show past climates. Bubbles of ancient air trapped inside glaciers record what the atmosphere was like.
Physical animal adaptations in Antarctica
Apart from habitats, which provide food, water and shelter, animals also depend on their physical features – called adaptations. These develop over many generations. Penguins, for example, have heavy, solid bones that act like a diver's weight belt, allowing them to stay underwater. Their wings, shaped like flippers, help them "fly" underwater.
Physical properties of water and ice
Cold water molecules move faster with increasing pressure. Hot water freezes faster than cold water. Ice melts when compressed except at high pressures when liquid water freezes when compressed.
Plate tectonics
A scientific theory of geology that has been developed to explain the observed evidence for large scale motions of the Earth's lithosphere.
Sea ice, icebergs and ecosystems
Icebergs can cause an expansion of sea ice, which inhibits penguin movements from feeding grounds in the open ocean to the breeding areas, and also inhibits the growth of phytoplankton – a major food source for krill. Without enough phytoplankton, entire food chains in the Antarctic can collapse.
Sea ice, icebergs and glaciers
Sea ice forms from salty ocean water. Icebergs and glaciers form from fresh water or snow. Sea ice grows, forms and melts strictly in the ocean. Glaciers are considered land ice, and icebergs are chunks of ice that break off glaciers and fall into the ocean.
Weather in Antarctica
Antarctica is surrounded by ocean, with 98% of its area covered with snow and ice. Antarctica reflects most of the sun's light rather than absorbing it. The extreme dryness of the air causes any heat that is radiated back into the atmosphere to be lost instead of being absorbed by the water vapour in the atmosphere.
