Influence of thermal stratification on aquatic community structure and water quality across freshwater ecosystems

Climate change intensifies thermal stratification in lakes, altering oxygen, nutrients, and habitats, which reduces aquatic biodiversity, modifies biological communities, and compromises the ecological resilience of these ecosystems. In this context, the objective was to evaluate, through a systematic review, the impact of thermal stratification on aquatic biodiversity in lake systems, analyzing changes in richness, abundance, and biological composition associated with thermal stratification. The methodology was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Population, Intervention, Comparison, and Outcome (PICO) approach to ensure rigor and reproducibility. A structured Boolean search in Scopus initially identified 854 records. After applying the inclusion criteria (publications from 2015 to 2025, English language, and quantitative physicochemical and biological data) and the PRISMA screening process, 33 studies were selected for the systematic review. The results show that thermal stratification reduces oxygen in the hypolimnion, favors tolerant species and decreases diversity, with cyanobacteria dominance, trophic simplification and habitat restriction, while thermal mixing promotes a partial recovery of biodiversity, although temporary and dependent on the type of lake, being more effective in deep temperate systems than in tropical ones; overall, thermal stratification is confirmed as a key factor regulating biodiversity patterns and water quality in lake ecosystems.