ABSTRACT
Sea ice is an important component of the physical environment in polar regions and strongly affects all organisms living in these areas. Ice effectively reduces the amount of light reaching the water column and reduces heat and gas exchange and vertical mixing. Microalgae that live in close association with sea ice, either attached to ice crystals or in the interstitial water found between ice crystals, are collectively called ice algae. N. N. Zubov used the terms ice plankton and cryoplankton for organisms peculiar to sea ice that develop during the summer in and around ice and form communities. The ecology of the ice algae is complex. Two surface ice communities occur in the Antarctic. The first forms when the weight of the snow layer is sufficient to depress the ice and seawater containing algal cells floods the snow-ice interface. The second surface community develops on fast ice when there is not enough snow to depress the ice.
