Evaluation of microbial diversity of the microbial mat from the extremely acidic Lake Robule (Bor, Serbia)

Extremely acidic environments are frequently formed in areas impacted by mining activities, and Lake Robule is such an ecosystem. Although an extreme environment, Lake Robule is inhabited by acidophilic microorganisms. We investigated biodiversity of the macroscopic structure known as a microbial mat formed on the lake bottom in shallow waters. Microbial mats are common in acidic environments, but their composition can differ significantly from site to site. Microbial diversity of the mat from Lake Robule was investigated using both cultivation-dependent and metagenomic approaches. The results showed the mat to be mostly inhabited by heterotrophic acidophilic bacteria. When compared to the microbial community of Lake Robule’s surface water, the microbial mat proved to be a more complex community. A biogeochemical model of the mat of Lake Robule is proposed on the basis of our results and available published data