Physical controls on the development and characteristics of Antarctic sea ice biological communities— a review and synthesis

Abstract

Ice structures found in Antarctic sea ice and related morphological processes are summarized, including: frazil ice growth; the flooded snow layer; pressure ridge induced flooding; thermally driven brine drainage; and platelet-ice formation. The associated colonization, physiological adaptation, and growth of sea ice biota within these structures, to the levels presently identifiable, are also reviewed. A strong interaction exists between the physical processes that form, evolve and deteriorate sea ice, and the biological communities located within sea ice. Variability of ice structure and associated biological communities over small spatial scales necessitated analysis of the biological component in combination with physical and chemical properties of the sea ice. The ice microstructure provides indications of the growth and evolution of the ice properties and initially defines how ice biota colonize the ice. The light, temperature, space and nutrient fields within which ice biota subsequently adapt and grow, are the other key determinants of the biology. While the ice microstructure shapes the localized biological response, relatively large regions of pack ice have characteristic microstructures. Regional patterns of biomass and biological productivity within the Antarctic sea ice zone may therefore be predictable as a result of these physical-biological associations. Examples from the drifting pack ice and fast ice zones of the Weddell and Ross Seas are given.