IMPACTS ASSESSMENT OF DESALINATION BRINE DISCHARGE ON THE MARINE MICROBIAL BIODIVERSITY: A METAGENOMIC APPROACH

Abstract

Being a hotspot of desalination, the health of the marine ecosystem of the Arabian Gulf is facing a serious threat. Many studies are suggesting that desalination activities could potentially harm the marine life, however, little experimental data are being provided in this regard. The current study is dedicated to assessing the effect of discharging desalination brine into the sea on the marine microbiome. Umm Al Houl desalination plant in Al Wakra was chosen as a case study, where spatiotemporal investigation of sea microbiome diversity was carried out. The novelty in this study is the utilization of the metagenomic approach, where the microbiome sensitivity will be assessed passively by studying the environmental DNA of seawater. The result of the study suggests that the physico-chemical characteristics of the seawater receiving the brine were not altered, neither spatially nor temporally. Slight differences were noted between different locations; however, the changes were not correlated with distance from brine outfall. The resulting differences were likely the result of tides, waves, and other seawater dynamics. Similarly, when measuring the biodiversity of the microbiome from different samples, random differences were existing that could not be explained as a response of sample's proximity to the brine outfall. Which also indicates the effect seawater dynamics. However, the existence of seasonal differences was observed as summer season had higher diversity compared to the winter. Further investigations and long-time monitoring are required to understand the effect of discharged desalination brine on the marine microbiome. Nevertheless, this study provides a foundation for future research to be conducted on the Arabian Gulf's microbial diversity.