Impacts of organophosphate pesticide types and concentrations on aquatic bacterial communities and carbon cycling

Organophosphorus pesticides (OPPs) are important chemical stressors in aquatic ecosystems, and they attract increasing more attentions recently. However, the impacts of different OPPs on carbon cycling remain unclear, particularly for those functional-yet-uncultivable microbes. This study investigated the change in lake aquatic microbial communities in the presence of dichlorvos, monocrotophos, omethoate and parathion. All OPPs significantly inhibited biomass (p<0.05) and the expression of carbon cycle-related cbbLG gene (p<0.01), and altered aquatic microbial community structure, interaction, and assembly. Variance partitioning analysis showed a stronger impact of pesticide type on microbial biomass and community structure, where pesticide concentration played more significant roles in carbon cycling. From analysis of cbbLG gene and PICRUSt2, Luteolibacter and Verrucomicrobiaceae assimilated inorganic carbon through Wood-Ljungdahl pathway, whereas it was Calvin-Benson-Bassham cycle for Cyanobium PCC-6307. This work provides a deeper insight into the behavior and mechanisms of microbial community change in aquatic system in response to OPPs, and explicitly unravels the impacts of OPPs on their carbon-cycling functions. Organophosphorus pesticides present substantial risks due to their high toxicity, potentially causing health problems in humans and environmental harm. They've led to varying degrees of aquatic pollution, impacting biodiversity and stability. Our research delves into the diverse effects of different types and concentrations of OPPs on microbial communities and the carbon cycle in aquatic environments. Understanding these complexities is crucial for managing the repercussions of pesticide exposure on aquatic ecosystems and carbon dynamics, vital for preserving ecological health amidst contamination.