Item

Abstract

During the last five decades, the Aral Sea has gradually changed from a
saline water body to a hypersaline lake. Microbial community inhabiting
the Aral Sea has been through a succession and continuous adaptation
during the last 50 years of increasing salinization, but so far, the
microbial diversity has not been explored. Prokaryotic diversity of the
Large Aral Sea using cultivation-independent methods based on
determination of environmental 16S rRNA gene sequences revealed a
microbial community related to typical marine or (hyper) saline-adapted
Bacteria and Archaea. The archaeal sequences were phylogenetically
affiliated with the order Halobacteriales, with a large number of
operational taxonomic units constituting a novel cluster in the
Haloferacaceae family. Bacterial community analysis indicated a higher
diversity with representatives belonging to Proteobacteria,
Actinobacteria and Bacteroidetes. Many members of Alphaproteobacteria
and Gammaproteobacteria were affiliated with genera like Roseovarius,
Idiomarina and Spiribacter which have previously been found in marine or
hypersaline waters. The majority of the phylotypes was most closely
related to uncultivated organisms and shared less than 97% identity with
their closest match in GenBank, indicating a unique community structure
in the Large Aral Sea with mostly novel species or genera.