Climate change-induced pressures and increased water demand impose an</p><p>additional threat to the sustainability of coastal freshwater systems.</p><p>The changes in precipitation patterns and quantity, rising seawater</p><p>level, and air temperature contributed to the irregularity of the</p><p>available freshwater resources and even induced salinization of the</p><p>previously freshwater systems. Lake Vrana is the largest surface</p><p>freshwater resource in mid-Dalmatia, while the local springs are heavily</p><p>used in agriculture. The karstified carbonate ridge that separates the</p><p>lake from the Adriatic Sea enables seawater intrusion if the lake's</p><p>precipitation-evaporation balance is disturbed. The impact of</p><p>anthropogenic activities and drought exuberated salinization on</p><p>microbial communities in Lake Vrana was tracked using 16S rRNA gene</p><p>sequencing. By monitoring changes in physio-chemical parameters and</p><p>microbial communities, we studied the ecosystem response to salinization</p><p>and its recovery. The study aimed to determine how the spatio-temporal</p><p>changes in water ion content act as a selective force on microbial</p><p>community structure. Water column samples were sequentially filtered to</p><p>separate particle-associated and free-living microbes and determine the</p><p>potential differential salinity impact on microbial communities. The</p><p>relative abundance of halotolerant opportunistic taxa increased as</p><p>salinization progressed. This study represents a valuable contribution</p><p>to understanding the impact of the Freshwater Salinization Syndrome on</p><p>the Mediterranean lake microbial communities and the ecosystem</p><p>resilience. Sequencing was performed at the Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna under the project ID JMF-2112-11.
