Twenty Years of Research in Ecosystem Functions in Aquatic Microbial Ecotoxicology.

This article systematically reviews 20 years (2000–2020) of research on the effects of pesticides on ecosystem functions supported by aquatic microbial communities, focusing on autotrophic (photosynthetic) and heterotrophic (decomposer) microorganisms in freshwater environments. It highlights that pesticide exposure—primarily herbicides affecting autotrophs and fungicides targeting heterotrophs—impairs key ecosystem functions such as biodiversity maintenance, organic matter production and decomposition, nutrient cycling, and gas regulation, though responses vary by microbial group and pesticide type. The review identifies significant research gaps, including limited studies on chronic exposures, combined effects on both microbial components, underexplored functions (e.g., protozoan roles, minor nutrient cycles), and the need for integrative approaches linking molecular to ecosystem-level effects. It emphasizes the importance of incorporating functional endpoints into ecological risk assessments to better understand and manage pesticide impacts on freshwater microbial biodiversity and ecosystem services.