Author(s)

Paul-Alain Nana^1*, Moïse Nola², Geneviève Bricheux³, Zéphyrin Fokam⁴, Pierre Ngassam², Dickson Achuo Enah², Jonathan Colombet³, Agnès Vellet³, Anne Mone³, Viviane Ravet³, Didier Debroas³, Télesphore Sime-Ngando³

¹Department of Oceanography, Institute of Fisheries and Aquatic Sciences, University of Douala, Douala, Cameroon.
²Laboratory of Hydrobiology and Environment, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.
³Laboratory Microorganisms: Genome and Environment, UMR CNRS 6023, Clermont Auvergne University, Clermont-Ferrand, France.
⁴Department of Biology, Higher Teacher Training College, University of Bamenda, Bamenda, Cameroon.

This study explores the diversity and structure of prokaryotic communities (Archaea and Bacteria) of 2 tropical volcanic lakes (Nyos and Monoun) in Cameroon, using 16SrRNA sequences. Metagenomics analysis of sequences showed that most OTUs (Operational Taxonomic Units) were associated with 26 phyla (23 for Bacteria and 3 for Archaea) in Nyos and 36 phyla (33 for Bacteria and 3 for Archaea) in Monoun. In both lakes, Proteobacteria for Bacteria and Crenarchaea for Archaea were predominant and present at all depths but in different proportions. Bacterial community compositions were generally dominated by members of Proteobacteria, Firmicutes, Actinobacteria, Chloroflexi and Bacteroidetes covering about 98% of the sequences. Crenarchaea, Thaumarchaea and Euryarchaea were the three main phyla of Archaea common to both lakes. The amount of virus and total bacteria was determined by flow cytometry technic and the evaluated ratio ranged from 0.2 to 1.2 at Nyos and from 0.6 to 2.6 at Monoun. For both lakes, the correlation was very significant between viruses and total bacteria. The depth-dependent variability is discussed with chemical and physical environmental parameters. These could significantly influence virus-mediated bacterial lysis and abundance and vertical stratification of the prokaryotic community.

Bacteria, Flow Cytometry, Lakes Nyos and Monoun, OTUs, Viruses

Nana, P. , Nola, M. , Bricheux, G. , Fokam, Z. , Ngassam, P. , Enah, D. , Colombet, J. , Vellet, A. , Mone, A. , Ravet, V. , Debroas, D. and Sime-Ngando, T. (2020) Diversity and Structure of the Prokaryotic Communities Indigenous to Two Volcanic Lakes: Nyos and Monoun in Cameroon. Open Journal of Ecology, 10, 632-650. doi: 10.4236/oje.2020.109039.