A comprehensive suite of geochemical samples and measurements from a selection of meltwater ponds at Bratina Island was collected in the 2005/06 and 2006/07 seasons. The purpose was to help identify interactions between inorganic and organic carbon and the biogeochemical cycling of this element within meltwater ponds and to assess model predictions against observed winter freezing conditions in ... certain ponds. In the first season of study four melt water ponds were selected for sampling based chemical stratification profiles including conductivity profiles taken in the centre of each pond at 5cm and 10cm intervals, representative depths identified to sample based on the stratified layers, at each depth water samples were collected for nutrient, cation, anion bicarbonate, sulphide, dissolved organic carbon, trace metal and arsenic analysis with temperature, pH, conductivity, dissolved oxygen and Eh measured immediately for each sample. In the second season of the study, seven melt water ponds were selected and sampled for collection and in situ measurements of chemical profile data and water samples. Sediment and salt samples were also collected from within and around ponds in this area over both seasons to help characterise the geochemical extremes in melt water ponds. Extensive sampling of microbial mat, sediment and water communities, along with corresponding environmental data and water samples and measurements of key environmental processes, were used to understand the effects of water chemistry on species composition.