فهرست نشریات علمی دسترسی آزاد ایران

Biological Soil Crusts (BSCs) are formed by the activity of various groups of microorganisms such as green microalgae, cyanobacteria, fungi, and bacteria. Biological soil crusts are ecosystem engineers across ‎all terrestrial environments, especially in drylands; yet their resilience in intensively ‎managed, saline-alkaline agricultural and horticultural soils remains unexplored. This study characterized algal diversity in relation to selected soil biochemical properties of BSCs across nine agricultural and horticultural sites in Northeast Iran. For this purpose, pH, EC, and chlorophyll content were measured according to established methodologies. Soil chemical analyses ‎revealed high pH and electrical conductivity (EC) in some samples of biological soil ‎crusts from the studied sites. According to the results, Cyanophyta and Chlorophyta ‎were the dominant algal groups in all collected BSC samples in Northeastern Iran. Also, based on the results, a ‎significant negative correlation was found between soil pH and chlorophyll a content. ‎Although the EC level in soil was negatively correlated with chlorophyll content, the algal ‎community comprised extremophile taxa tolerant to these stressful conditions. In addition, the ‎number of identified taxa correlated negatively with soil pH and EC levels, and ‎positively with chlorophyll content. The ‎genera Chlorococcum from Chlorophyta and Phormidium (Cyanophyta) were dominant, ‎with their prevalence underscoring their documented salinity tolerance. Additionally, other identified ‎genera, such as Pseudanabaena, Nostoc, Calothrix, and a few diatom genera, further confirm the presence of stress-adapted flora. This study demonstrates that elevated soil pH and EC are key environmental filters that shape biological soil crusts' algal communities, selecting for a specialized, tolerant consortium.