New insights in bacterial and eukaryotic diversity of microbial mats inhabiting exploited and abandoned salterns at the Ré Island (France)

Abstract

In order to understand the effect of human practices on microbial mats organisation, the study aimed to investigate the biodiversity within microbial mats from exploited and abandoned salterns. Despite several attempts, archaeal 16S rRNA gene fragment sequences were not obtained, indicating that microbial mats were probably dominated by Bacteria with very low abundance of Archaea (< 1%).Thus, the study compared the bacterial and meiofaunal diversity of microbial mats from abandoned and exploited salterns. The higher salinity (101 ± 3.7 psu vs. 51.1 ± 0.7 psu; Welch t-test p<0.05) of the exploited site maintained lower bacterial diversity in comparison to the abandoned site where the salinity gradient was no longer maintained. However, the microbial mats exhibited similar bacterial class composition while the eukaryotic diversity was significantly higher in the exploited saltern. The abandoned saltern was dominated by sulfate-reducing bacteria and Nematoda, while the exploited saltern was characterized by the presence of halophilic bacteria belonging to Marinobacter, Salinivibrio and Rhodohalobacter genera, and the larger abundance of Hypotrichia (ciliates). Such bacterial and eukaryotic diversity difference might be explained by human actions for salt recovery in exploited salterns such as scraping the surface of microbial mat and increasing salinity renewing the microbial mat each year. Such action decreases the bacterial diversity changing the food web structure that favour the presence of a larger diversity of eukaryotic organisms. Our study provides new insights on microbial mat communities inhabiting salterns, especially the consequences of abandoning saltern exploitation.

Microbial community structure and shift pattern of industry brine after a long-term static storage in closed tank

“…In this paper, bacterial and archaeal communities in different brine samples were analyzed by Illumina highthroughput sequencing technology. Overall, the bacterial communities in the brine samples are mainly composed of Proteobacteria and Bacteroidetes (Figure 4A), which is consistent with other researches (Boujelben et al, 2012;Kalwasinska et al, 2018;Mazière et al, 2021). In fact, Proteobacteria and Bacteroidetes are also the dominant phyla in other saline waters (Boujelben et al, 2012;Kalwasinska et al, 2018;Cardoso et al, 2019), playing an important role in carbon and nitrogen cycling (Bernhard et al, 2012;Wong et al, 2015).…”

Biomineralization by Extremely Halophilic and Metal-Tolerant Community Members from a Sulfate-Dominated Metal-Rich Environment

“…They can be applied to bioremediation approaches reducing the impact of high contamination caused by salt or heavy metals including radionuclides [12]. We expected to find highly different, specialized microbiomes in a gradient of contamination with high salt and metal concentrations [1][2][3][4]. The site featured high Cs and Sr concentrations, which were accompanied by Mn and sulfate as well as chloride concentrations at high levels.…”

“…Environments with high salt concentrations such as brines, salty soils, or sediments drive adaptation of the microbial community present at such sites [1][2][3][4]. Specific contaminants include not only NaCl, but specifically due to mining operations of sulfidic ores, high sulfate concentrations may lead to halophilic communities establishing on such sites [5][6][7].…”

The application of plant growth-promoting rhizobacteria in Solanum lycopersicum production in the agricultural system: a review

“…A large number of taxonomic microbes include prokaryotic organisms (viruses, bacteria, and archaea) and eukaryotic organisms (algae, arthropods, fungi, nematodes, and protozoa) inhabit this soil. Bacteria and fungi contain mostly prevalent units revealing elementary ecological purposes ( Mazière et al, 2021 ). PGPR is designated and assists plant development as free-living bacteria inhabiting soil flourish well and competitively inhabit the plant roots ( Basu et al, 2021 ).…”