A series of 10 ponds, located away from the main influences of the penguin colony at Cape Hallett, were investigated for variation in chemistry and microbial mat development. Cores of benthic microbial mats were collected from each pond for particulate nutrient and pigment analyses, biomass determination and species composition. Surface water samples were also collected from each pond to determine ... phytoplankton chlorophyll a, particulate nutrients and dissolved nutrients. Additional microbial mat material and underlying sediments were collected for toxin and molecular analysis. Photosynthesis and nitrogen fixation experiments were conducted on microbial mats collected from each pond with conductivity and pH measurements, coupled with gross mat morphology used to select the most contrasting ponds. Photosynthesis and respiration rates were determined by measuring the rate of evolution or consumption of oxygen using oxygen electrodes. Samples for dissolved inorganic carbon uptake were taken for analysis. Nitrogen fixation was determined and gas samples from the nitrogen fixation were then collected for analysis by gas chromatography. Temperature, pH and conductivity were measured at the surface and deepest point of each pond. As all ponds were fully mixed, water samples for cation, anion and bicarbonate analyses were collected from the surface and bottom of the ponds only. Five cryoconite ponds on each of two glaciers, Tucker and Bornmann glaciers, were investigated. For each cryoconite hole, temperature, pH and conductivity profiles were taken through the water column. Water samples were collected for dissolved nutrients, chlorophyll a, particulate nutrients, cations, anions and bicarbonate analyses, while sediment samples were collected for pigment analysis and species composition.