Climate change projections for Carpathian soda pans on the basis of photosynthesis evidence from typical diatom species

The Carpathian Basin is home to a number of astatic soda pans which are especially vulnerable to the climate change due to their high degree of hydrological sensitivity. The photosynthetic plasticity of the three most dominant benthic diatom species (Nitzschia aurariae, N. reskovii, N. supralitorea) in a number of soda pans was measured, along with sulphate and chloride ion content; conductivity and temperature gradients were also recorded. On the basis of the maximal photosynthetic activity (Ps), climate models were employed to observe and predict the effects of climate change on photosynthesis over three time-spans: past (1970–2000), recent past (2005–2015) and projected future (2041–2060). Comparing the periods, it becomes apparent that climate change has a significant effect on photosynthesis and the photosynthetically active period of the Nitzschia species, the dominant primary producers in soda pans, by enhancing their photosynthetic activity and extending their vegetation period by two months. Due to the breadth of their ecological niche, the competitive advantages of the diatom species studied in the course of this research as against others are expected to prevail under the conditions predicted by the climate scenario presented here. [Display omitted] •Nitzschia ssp. have high optima and tolerance along more environmental gradients.•They have competitive advantages due to their broad fundamental niches.•Climate change intensifies the photosynthesis of these dominant primary producers.•Furthermore, it extends their vegetation period in soda pans.•Increasing functional importance of these ecosystems is expected in the future.