Samples of algae and bacteria were from the east and west lobe of Lake Bonney (sediment), Lake Miers sediment, Lake Fryxell (9.75m and 14m sediment) and an oligotrophic and eutrophic pond at Cape Bird. All samples were incubated for 0, 3h, 6h, 12h, and 24h and then subjected to experiments measuring photosynthesis, nitrate reduction and sulphate reduction. During photosynthesis small organic ... compounds are excreted by the photosynthesizing algae and bacteria and used as a source of food for those which are not. Measurements of heterotrophic uptake of organic compounds was determined. Bacterial numbers present in a series of counts were done for the main groups of bacteria involved including: total bacteria, photosynthetic bacteria, nitrate reducing bacteria and sulphate reducing bacteria. The enrichment procedure was undertaken to encourage the growth of specific types of bacteria.