Cyanobacterial Diversity associated to the Rock-Cut Caves of Nashik, Maharashtra, India

Abstract

Cyanobacterial biofilms are pioneering communities on lithic surfaces and may contribute to discoloration, moisture, mineral interactions and biodeterioration of cultural heritage. The present study documents the morphological diversity of cyanobacteria associated with five rock-cut cave complexes of Nashik District, Maharashtra, India: Chamar Leni, Pandav Leni, Jain Caves, Trigalwadi Caves and Ankai Caves. Samples were collected from moist and wet rock walls, floors, sculptures, soil-associated surfaces, water-contact zones and nearby subaerophytic substrates. Environmental observations included temperature, pH and relative humidity. The compiled checklist comprised 55 morphotaxa representing 18 genera and 72 site occurrences. Coccoid forms represented 25 taxa (45.5%), non-heterocystous filamentous forms traditionally grouped as Oscillatoriales represented 13 taxa (23.6%) and heterocystous forms represented 17 taxa (30.9%). Pandav Leni exhibited the highest observed richness (33 taxa), followed by Ankai (18), Jain (8), Chamar Leni (7) and Trigalwadi (6). Nostoc commune was recorded at all five study sites, whereas Aphanothece castagnei and Gloeocapsa compacta each occurred at three sites. The assemblage contained numerous taxa with mucilaginous sheaths, thick envelopes, false branching or heterocysts, traits consistent with persistence under fluctuating moisture and high irradiance. The results support previous Indian and International observations that cyanobacteria can form persistent lithophytic biofilms on heritage stone surfaces. However, because identification in the present study was morphology-based, the reported species should be regarded as morphotaxa pending molecular confirmation. Future work should integrate 16S rRNA/16S–23S ITS sequencing, quantitative abundance measurements, stone physicochemistry and seasonal monitoring to resolve cryptic diversity and strengthen conservation applications.