9316736 Raymond Recently it has been shown that diatoms from sea ice platelets in McMurdo Sound, Antarctica, release a proteinaceous, ice-active substance that, at natural concentrations, causes dense pitting on the basal surfaces of growing ice platelets. At present, only fish, insects and bacteria are known to produce an ice-active substance. Thus, the ice-active substances associated with sea- ice algae are of interest because it is the first to be associated with algae, and it may provide new insights on how biomolecules interact with ice. The objectives of this project are to biochemically, biophysically and physiologically characterize the ice-active substance. On a biochemical and biophysical level, the objectives are to purify the ice-active substance, to determine its chemical composition and structure, and to characterize its effect on the growth of ice crystals. On a physiological level, the objective is to determine the relationship between algal production of ice-active substance and the environment. More specifically, what is the temporal and spatial distribution of the ice-active substance in McMurdo Sound, how is its production influenced by temperature and light, and among which species and habitats is it found? The long-term goal of project is to understand what role ice-active substances play in the sea-ice algal community. ***
