The supraglacial environment is an integral part of the glacial ecosystem. It is known to harbour an active microbial community that is concentrated in cryoconite holes, unique freshwater environments formed when solar-heated dark debris melts down into the glacier ice. Cryoconite holes are potentially important sources of organic carbon and nutrients to the glacial system. Field measurements and laboratory analyses and experiments were undertaken to explore the chemical environment, to determine the inorganic carbon uptake rate and the interactions between photosynthesis and water chemistry, and to examine the role ot phosphorus as the limiting nutrient for the cryoconite community from Werenskioldbreen, a well-researched Svalbard glacier.