Environments
The continent of Antarctica has a limited number of finely balanced
ecosystems, most of which are marine based. Krill, the shrimp-like crustacea,
is the key species in the marine food chain. On the continent itself,
however, there are small areas around the fringes where the land is not
permanently covered by ice. Such sites are very often home to lower forms of
plant life, such as bacteria, lichens and mosses, and small animals, the
largest of which is the wingless midge.
The freshwater and saline lakes found in the oases around the continent may
also support relatively simple ecosystems. Great variations in climatic
conditions on Antarctica prevent the establishment of higher plant and animal
species, and keep land-based ecosystems very simple.
|
