Spatiotemporal dynamics of the microbial community in the water column of Ojo de Liebre Lagoon, Baja California Sur, Mexico

Abstract

Microbial communities in hypersaline environments play a key role in biogeochemical cycles and ecological productivity. This is the first study to characterize the composition, structure, and metabolic potential of the prokaryotic community in the water column of Ojo de Liebre Lagoon (Baja California Sur, Mexico), a hypersaline ecosystem of ecological and socioeconomic importance. From the information obtained from 4 sampling campaigns (2021–2022) conducted at 18 stations, we analyzed physicochemical variables (salinity, temperature, and density) and sequenced the V4–V5 region of the 16S rRNA gene. Data were processed using QIIME2, and metabolic potential was inferred via PICRUSt2. The community was dominated by Actinobacteriota, Bacteroidota, Cyanobacteriota, Pseudomonadota, and Verrucomicrobiota, with spatiotemporal differences linked to temperature (r² = 0.77, P = 0.001) and salinity (r² = 0.39, P = 0.014) gradients. Rare taxa (<1% abundance), such as Thermoanaerobaculales and Desulfobacterota, contributed to diversity, particularly in November. Metabolic inference revealed significant pathways (P < 0.05), including vitamin B6 biosynthesis, chitin degradation, and nitrate reduction, suggesting roles in biogeochemical cycles and adaptation to extreme conditions. The prokaryotic community structure in the lagoon responded to physical and chemical variations, with a stable taxonomic core and rare taxa enhancing diversity under specific conditions. The inferred metabolic potential highlights their participation in biogeochemical processes and their capacity to degrade complex organic compounds. These results establish a baseline for understanding microbial dynamics in hypersaline systems and their impact on ecosystem function.