Exploring the resilience of playa lake ecosystems to climate change: A microbial perspective

Playa lakes, ephemeral water bodies found in arid and semi-arid regions, are increasingly impacted by climate change. The Mexican playa Lake Atotonilco has experienced a significant decline in water volume, leading to increased salinity and making it a valuable model for assessing climate impacts. Using 16S rRNA sequencing, this study investigated the responses of microbial communities and their contributions to key biogeochemical cycles, including those related to greenhouse gas dynamics. Spatial differences in physicochemical parameters were observed: channels and wastewater treatment plant (WWTP) effluent showed elevated BOD₅, COD, coliforms, and pH above regulatory limits, whereas the lake displayed higher DO but increased TP and TKN. Bacterial communities exhibited marked seasonal and depth-related shifts, reflecting strategies that support ecosystem resilience. To robustly identify differentially abundant taxa, two methods (ANCOM-BC2 and DESeq2) were implemented, which consistently detected significant differences across seasons. Despite strong environmental fluctuations, a core microbial community persisted, suggesting functional continuity in biogeochemical cycling. This study provides a comprehensive assessment of microbial dynamics in a playa lake, integrating community structure with physicochemical variability to reveal bacterial responses to climate-driven environmental change. Because playa and other shallow lakes worldwide are experiencing increasing desiccation, salinization, and nutrient imbalances, defining these microbial processes is essential for anticipating ecological change. This study provides a needed baseline for future research and offers key insights for managing climate-vulnerable aquatic ecosystems in arid regions.