Fast ice forms and remains ‘land fast’ along the coast, where it is attached to the shore, to an ice wall, to an ice front, between shoals or grounded icebergs. Vertical fluctuations may be observed during changes of sea-level. Fast ice acts like a belt around the Antarctic coast, regulating the flow of ice shelves and glaciers into the sea.
Fast ice may be formed in situ from sea water or by freezing of pack ice of any age to the shore, and it may extend a few metres or several hundred kilometres from the coast. Fast ice may be more than one year old and may then be prefixed with the appropriate age category (old, second-year, or multi-year).
Scientists have been monitoring fast ice in East Antarctica since the 1950s. Ice cores form a long term record of East Antarctica fast ice and are used in science projects. Basic information on the cores is recorded in the field, before they are taken back to Australia for more detailed analysis.
In Spring, zooplankton feed on the nourishing algae found in the fast ice. Emperor penguins breed on fast ice, and Weddell seals give birth on it.
Young coastal ice
Young coastal ice is the initial stage of fast ice formation consisting of nilas or young ice, its width varying from a few metres up to 100–200 m from the shoreline.
Anchor ice is submerged ice attached or anchored to the bottom, irrespective of the nature of its formation.