Impacts of temperature regimes and radiation (PAR and UVR) conditions on the possible geographic distribution of desmids This preliminary study revealed that the Cosmarium strains collected from various geographic regions demonstrated different physiological behaviour which is in accordance with the climate prevailing at the site of the clonal origin. The species and strain specific differences were expressed under a set of varying temperature and radiation (PAR and UVR) conditions demonstrating that the responses are genetically preserved (i.e. such physiological performances can be considered as adaptations genotypic responses to long term environmental changes). Acclimation under relatively low light temperature conditions of a climate chamber affected more photosynthetic parameters than morphological or growth parameters.