Major impacts of caving activities on cave microbial diversity: case study of Morca Cave, Turkey.

Some of microorganisms identified in cave ecosystems have been reported to play a permanent and strategic role for maintaining life of these environments. Human entrance into caves can induce some changes of cave physicochemical parameters which ultimately impacts the living organisms. In these facts, for the first time, Morca Cave was explored in a purpose to evaluate the impacts that can be caused by the human activities on microbial diversity in a limited period of time. Morca is a karts cave located in the Taşeli Plateau in the Middle Taurus mountains in Turkey. The first entrance into this cave was in 2018, and expeditors reached to - 500 m. During the second expedition in 2019, a camp was established at the - 1040-m depth during 4 days. In order to evaluate the human impacts in a new explored cave, this camping depth is chosen to be our studied area because it was its first entrance. Before the installation and at the end of the camp, sediments and surface samples were taken from different points of the camp area and around. Sequencing of 16 s rRNA of each sample to isolate DNA by using the next-generation sequencing (NGS) method was performed. The profile of the microbial diversity before the camping revealed that the class Thermoplasmata was dominated the archaea group and Gammaproteobacteria and Alphaproteobacteria were the most dominant bacterial classes. After the camp, most studied sites were noted with a decrease of microbial diversity especially the previous cited classes strains. Bacteria belonging to Bacilli class have increased after the camp. Increase of bacteria that are belonging to Bacteroidia has also observed in the most active areas. This present study highlight how cave microbial diversity can respond to the human activities within a short period inside a closed cave. Furthermore, it may constitute a solid basis and support on the improvement of techniques for cave management and expedition planning for the conservation of cave nature.