This study investigates minerals and microorganisms effects on fluid chemistry through a continuous enrichment culture in a gas-lift bioreactor during the MoMARsat’19 cruise. A sulfate-based chimney and buoyant hydrothermal fluid, both collected in situ at the Aisics vent of the Lucky Strike hydrothermal field, were incubated for 18 days under physico-chemical conditions mimicking those of in situ diffuse vents. We present the evolution of elemental and Sr, and Li isotopic compositions of the bioreactor fluid, alongside Bacteria and Archaea diversity, and analyze the mineral saturation state of the fluid through geochemical modeling. Our results reveal that the microbial diversity in the bioreactor reflects that of the sulfate-based chimney. During the initial 168 h, minerals precipitation/dissolution primarily controlled the elemental and Sr isotopic composition of the fluid. From 168 h to 264 h, sulfate-reducing Archaea (Archaeoglobi) disappeared in favor of sulfur-reducing Archaea (Thermoprotei and Thermococci). This coincides with a drastic increase in trace element concentrations and less radiogenic 87Sr/86Sr ratios, showcasing microbial influence on the fluid. From 264 h onwards, with stable sulfur-reducing archaeal diversity, mineral saturation state primarily controls the elemental composition of the fluid. However, we attribute the observed increase in the 87Sr/86Sr ratio and δ7Li to changes in bacterial diversity, notably increasing Deinococci abundance. This study reveals that in diffuse vent environments related to the sulfur cycle: (i) microorganism and mineral influence fluid chemistry over time, (ii) microbial diversity affects trace metal concentrations and isotopic signatures, and (iii) the 87Sr/86Sr ratio trace mineral-fluid-microorganism interactions, unlike δ7Li.