Life Under Artificial Light in a Unique Habitat: Exploring Lampenflora in Ravništarka Cave, Serbia

The phototrophic component of the lampenflora was studied in two seasons in Ravništarka Cave in Serbia. A distinct and diverse lampenflora developed in the vicinity of artificial lights: green to dark, epilithic to endolithic, dominated by microorganisms to macroorganisms or dominated by Cyanobacteria to green algae. The phototrophic microorganisms studied belong to the Cyanobacteria, Chlorophyta (green algae) and Bacillariophyta (diatoms). Diatoms were characterized with highest number of taxa recorded, while green algae were abundant in the biofilms biomass at many sites. Several dominant genera were identified in each group, but the most distinctive diatom genus was <i>Humidophila</i>, while <i>Leptolyngbya</i> stood out among the Cyanobacteria. <i>Stichococcus</i> was the most species-rich green algae, but <i>Chlorella</i> sp. and <i>Bracteacoccus minor</i> were also found at most sampling sites. We found that many of the dominant genera are reported in lampenflora worldwide, while some, such as <i>Sellaphora</i>, are rarely encountered. The ecological parameters were mostly site-specific, and some also depended on the season of sampling. After redundancy analysis, relative humidity and substrate moisture were statistically significant ecological parameters that correlated positively with the Bacillariophyta. The work represents a significant contribution to the knowledge of the phototrophic community of lampenflora and to the understanding of their development in show caves.