Biodiversity of Phototrophs and Culturable Fungi in Gobustan Caves

Abstract

Unique natural objects, such as the caves of the Gobustan National Historical and Artistic Preserve, are also of great cultural and historical value due to rock art and sites of ancient people. A favorable microclimate makes these habitats convenient for colonization by microbiota, including phototrophs. In arid regions with intense seasonal fluctuations of microclimatic parameters, the conditions for survival are the least favorable; therefore, it becomes especially important to determine the composition of communities that are the most adapted to specific conditions. This work aimed to identify the biodiversity of communities of caves and grottoes of the Gobustan Reserve. The studies were carried out in July 2019. Samples were analyzed for cyanobacteria and algae by microscopy and cultivation methods, microfungi were isolated by soil dilution, and the fouling glass method was also used. In total, 29 taxa of cyanobacteria and algae, 18 taxa of fungi, and 3 species of mosses were identified. The studied habitats were dominated by the algae Chlorella vulgaris, Aphanocapsa sp., and Stichococcus bacillaris; the subdominants were Jaaginema subtilissimum, Leptolyngbya tenuis, Chlorococcum minutum, and Humidophila contenta. Microfungi had the highest occurrence of Aspergillus niger, Aureobasidium pullulans, Alternaria alternata, and Talaromyces ruber. It was noted that cyanobacteria dominated in morphologically differentiated biofilms and green algae on the rocks. The greatest number of microfungi was found in the aphotic zone and bryophyte tufts. The dominance of green algae is atypical for most caves of other regions and may be associated with intense lighting of habitats. The absence of protonema is a consequence of the aridity and low moisture content of the substrates.