Life in the Underground: Hidden Cyanobacterial Diversity in Cave Lampenflora Assessed by Metabarcoding

Recent studies of understudied habitats, particularly caves, have revealed previously unrecognised cyanobacterial diversity. In this study, we used a metabarcoding approach to assess cyanobacterial communities in lampenflora developing in the most visited sections of Stopić Cave, Serbia. Two visually distinct lampenflora types were analysed: aerophytic lampenflora on exposed surfaces and submerged lampenflora within retained water, along with key environmental parameters. A wide range of Cyanobacteria was detected, including cave-adapted, rock-dwelling, atmophytic taxa from various habitats (deserts, thermal and saline environments), as well as species typically associated with freshwater and saline environments. Notably, many of the documented taxa have only recently been described. Dominant Cyanobacteria (>10%) included those assigned to Cyanothece aeruginosa, Loriellopsis cavernicola, Marileptolyngbya sina, Neochroococcus gongqingensis, Pseudocyanosarcina phycocyania, Scytonema hofmanii and Thainema salinarum, while representatives of the genera Chalicogloea, Crocosphaera, Dulcicalothrix, Gloeothece, Kovacikia, Timaviella, and Trichocoleus each contributed ≥1% of the community. In addition, Vampirovibrio chlorellavorus, a representative of Candidatus Melainabacteria, the non-photosynthetic relative of Cyanobacteria and an obligate parasite of Chlorella species, was detected in all aerophytic lampenflora.