The lakes and watercourses are habitats for various communities of cyanobacteria and algae, which are among the few primary producers in Antarctica. The amount of nutrients in the mineral-poor Antarctic environment is a limiting factor for the growth of freshwater autotrophs in most cases. In this study, the main aim was to assess the availability of mineral nitrogen for microorganisms in cyanobacterial mats in James Ross Island. The nitrate and ammonium ions in water environment were determined as well as the contents of major elements (C, N, P, S, Na, K, Ca, Mg, Al, Fe, Mn) in cyanobacterial mats. The molar ratios of C:N, C:P and N:P in mats were in focus. The growth of freshwater autotrophs seems not to be limited by the level of nitrogen, according to the content of available mineral nitrogen in water and the biogeochemical stoichiometry of C:N:P. The source of nutrients in the Ulu Peninsula is not obvious. The nitrogen fixation could enhance the nitrogen content in mats, which was observed in some samples containing the Nostoc sp.
Studies of the chemical composition of surface freshwaters of the Fugleberget drainage basin, Spitsbergen, were performed in the summer of 1979. It was found that activity of birds (little auk) is the main factor differentiating the chemical properties of waters of the drainage basin. The birds faeces cause the enrichment of waters with nutrients, fertilizing the environment. There is a dependence of the concentration of determined water chemistry parameters on the distance from the bird colony.
This phytoplankton study was conducted from May to September 2002, 2003 and 2005 during fountain-based water aeration in the pelagial of Jeziorak Mały urban lake in Poland. Differences in the abundance and biomass of phytoplankton groups (cyanobacteria, diatoms, chlorophytes, dinoflagellates, chrysophytes and cryptomonads) related to physico-chemical water parameters were analyzed at the fountain and in the lake centre. Fountain water-mixing changed phytoplankton growth likely by decreasing water temperature, oxygenation and nutrient concentrations. These induced a disturbance in the cyanobacteria and stimulated growth of phytoplankton groups in the water column. High phytoplankton abundance at 1 m depth at the fountain could relate with phytoplankton sinking in the water column. This additional water mixing also intensified sedimented organic matter decomposition, thus enhancing nutrient uptake by phytoplankton. These results are important for future shallow urban lake management.