The Arctic sea ice and its related
biota are unique, and the year-round persistence of the ice has allowed the development of ice
endemic species. The specialized
sympagic community within the sea ice is found in the tiny liquid filled network of pores and brine channels or at the ice-water interface. The organisms living within the sea ice are consequently small (<1mm), and dominated by
bacteria, and unicellular plants and animals.
Diatoms are considered the most important primary producers inside the ice with more than 200 species occurring in Arctic sea ice. In addition,
flagellates contribute to
biodiversity.
Protozoan and
metazoan ice
meiofauna, in particular
turbellarians,
nematodes,
crustaceans and
rotifers, can be abundant in all ice types year-round. In spring,
larvae and juveniles of
benthic animals (e.g.
polychaetes and
molluscs) migrate into coastal fast ice to feed on the ice
algae for a few weeks. A partially endemic
fauna, comprising mainly
gammaridean amphipods, thrives at the underside of ice floes. Locally and seasonally occurring at several hundred individuals per square meter, they are important mediators for particulate organic matter from the sea ice to the water column. Ice-associated and
pelagic crustaceans are the major food sources for
polar cod (
Boreogadus saida) that occurs in close association with sea ice and acts as the major link from the ice-related food web to seals and whales. While previous studies of coastal and offshore sea ice provided a glimpse of the seasonal and regional abundances and the diversity of the ice-associated biota, biodiversity in these communities is virtually unknown for all groups, from bacteria to metazoans. Many
taxa are likely still undiscovered due to the methodological problems in analyzing ice samples. The study of diversity of ice related environments is urgently required before they ultimately change with altering ice regimes and the likely loss of the multi-year ice cover. ==See also==