Heatwaves, elevated temperatures, and a pesticide cause interactive effects on multi-trophic levels of a freshwater ecosystem

• DOI: 10.1016/j.envpol.2023.121498
• Publication Date: 2023-03-23T08:12:13Z
• Authors: Markus Hermann; Edwin T.H.M. Peeters; Paul J. Van den B...
• Keywords: Freshwater ecosystem; Microcosm

Climate impacts of elevated temperatures and more severe frequent weather extremes like heatwaves are globally becoming discernible on nature. While a mechanistic understanding is pivotal for ecosystem management, stressors pesticides may interact with warming, leading to unpredictable effects freshwater ecosystems. These multiple stressor studies scarce experimental designs often lack environmental realism. To investigate the effects, we conducted microcosm experiment 48 days comprising benthic macroinvertebrates, zooplankton, phytoplankton, macrophytes, microbes. The fungicide carbendazim (100 μg/L) was investigated combined temperature scenarios representing (+4 °C) or (+0 +8 °C), both applied similar energy input daily fluctuating ambient (18 °C ± 1.5 which served as control. Measurements showed highest dissipation in water under followed by temperatures. Average concentrations were about 50% 16% sediment nominal concentration. In heated cosms, zooplankton community dynamics revealed an unexpected shift from Rotifera Cladocera Copepoda nauplii, indicating variations their thermal sensitivity, tolerance resilience. Notably, warming shaped responses similarly, suggesting heat intensity rather than distribution patterns determined structure. Heatwaves led significant early longer-lasting adverse that exacerbated over time being most sensitive likely due interactions. Finally, structural equation model demonstrated relationships between macrophytes significantly negative whereas positive macroinvertebrate abundances. relationship feeding abundance masked temperature-affected microbial leaf litter decomposition. Despite communities, our study highlights increased pesticide threat extremes. More intense thus cause alterations assemblages will adversely affect ecosystem's processes functions.