Temporal variation in culturable bacterial isolates and their enzyme-associated traits across sampling sites in Abu Dhabi salt flats

Salt-flats (sabkha) are extreme environments characterised by high salinity and alkalinity, supporting diverse halophilic and halotolerant bacteria with biotechnological potential. We investigated the culturable bacterial diversity in the Abu Dhabi salt-flats across three seasons- winter, transitional warmer period, and summer, focusing on temporal variations, salt tolerance, and enzymatic capabilities. Soil samples were collected from six salt-flat sites during each season, yielding 158 bacterial isolates identified using 16S rRNA gene sequencing. Bacillota was the dominant phylum across all seasons, with strains with the closest match with Bacillus paralicheniformis, Bacillus licheniformis, Bacillus vallismortis, and Bacillus tropicus being most abundant. Bacterial richness was at the transitional warmer period, indicating temporal influence on the culturable fraction. Salt tolerance assays based on qualitative growth observations showed that most recovered isolates grew in media containing 10–15% NaCl under the conditions tested. Qualitative enzyme screening indicated frequent positive reactions for cellulase, protease, hydrolase, and transferase-related activity, whereas amylase, lipase, and xylanase-related activity were detected less often. Maximum -likelihood phylogenetic analysis based on 16S rRNA gene sequences grouped the recovered isolates into three broad phylogenetic groupings, including a mixed cluster of Halomonas-and related taxa, a cluster containing several Bacillales-associated genera, and a larger grouping dominated by Bacillus -affiliated isolates. The observed phenotypic traits were distributed across multiple branches, but no statistically supported relationship between phylogeny and functional characteristics was established. Overall, these findings provide a preliminary observational overview of the culturable fraction recovered from salt-flat soils and its qualitative enzyme-related traits, providing a baseline for future quantitative and culture-independent investigations.