Taxonomic diversity of bacterial communities in the sediments of a soda lake in Arusha, Tanzania

Abstract

Soda lakes are special ecosystems with high salinity and alkalinity, notably found in the Great Rift Valley of East Africa. Given the unique nature of soda lakes, it is interesting and valuable to examine their bacterial composition as an initial step towards bioprospecting. This study provides the first metagenomic snapshots of bacterial communities inhabiting Lake Natron sediments using the 16S rRNA gene sequenced using a PacBio sequencing system. Results show high abundance and diversity of species in general, with notable dominance of Firmicutes, Bacteroidota, Actinomycetota, and Proteobacteria with the relative abundances of 45.21 %, 25.23 %, 12.59 %, and 23.29 %, respectively. At the class level, Bacteroidia (23.54 %), Gammaproteobacteria (22.32 %), Bacilli (19.66 %), and Clostridia (22.32 %) were the most dominant classes. At lower taxonomic ranks (especially at the genus and species levels), there was an increase in the percentage of unknown and “Candidate Phyla” species (i.e., those discovered using genetic methods but not yet fully characterized or classified), suggesting the potential presence of new bacterial taxa in Lake Natron. The diversity indices revealed a high level of community diversity, with a large number of species, the presence of rare species, and an even distribution of bacteria across the sampling points. Although this study provides the first report on the existence of different bacterial taxa in Lake Natron, additional investigation into the biotechnological importance of the found species is of importance; hence, a functional metagenomic study is advised.