A detailed investigation of the autoecology, morphology and life history of Prasiola calophylla were conducted to extend the existing data for the species. Data on distribution and growth patterns of the alga in the field was gathered by field observations, mapping, photography and sketches at Cape Royds and the Garwood Valley. At Cape Royds the area to the north of Blue Lake was examined in ... detail in order to relate the occurrence of P. calophyll to the effects of windblown saline aerosols from Backdoor Bay. At the Garwood Valley, extensive searches were made for the alga in streams and other habitats where percolating meltwater was expected to occur. A more detailed investigation was made in a single stream close to the campsite and some physico-chemical data was collected from this habitat. Simple experiments were performed to determine the ability of P. calophyll to resist washout from running water habitats. Microscopic examination of various growth forms and life stages of the alga was made.