Effect of an antidepressant on aquatic ecosystems in the presence of microplastics: A mesocosm study

• Published in: Environmental pollution (1987) 2024-09, Vol.357, p.124439, Article 124439
• Main Authors: Vasantha Raman, Nandini, Gebreyohanes Belay, Berte M., South, Josie, Botha, Tarryn L., Pegg, Josephine, Khosa, Dumisani, Mofu, Lubabalo, Walsh, Gina, Jordaan, Martine S., Koelmans, Albert A., Teurlincx, Sven, Helmsing, Nico R., de Jong, Nina, van Donk, Ellen, Lürling, Miquel, Wepener, Victor, Fernandes, Tânia V., de Senerpont Domis, Lisette N.
• Format: Article
• Language: English
• Subjects: acute exposure; Animals; antidepressants; Antidepressive Agents - pharmacology; Aquatic ecosystem functioning; aquatic food webs; Asellus aquaticus; biodegradation; Biomass; Chaoborus; chronic exposure; Daphnia - drug effects; Daphnia - physiology; Daphnia magna; dose response; Ecosystem; Environmental Monitoring; Fluoxetine; Food Chain; locomotion; macroinvertebrates; Microplastics; Microplastics - toxicity; Multiple stressors; Non-monotonic responses; nutrient availability; Pharmaceutical; phytoplankton; Phytoplankton - drug effects; pollution; sediments; species; Water Pollutants, Chemical - toxicity; zooplankton; Zooplankton - drug effects
• ISSN: 0269-7491; 1873-6424; 1873-6424
• DOI: 10.1016/j.envpol.2024.124439

Emerging pollutants, such as pharmaceuticals and microplastics have become a pressing concern due to their widespread presence and potential impacts on ecological systems. To assess the ecosystem-level effects of these pollutants within a multi-stressor context, we simulated real-world conditions by exposing a near-natural multi-trophic aquatic food web to a gradient of environmentally relevant concentrations of fluoxetine and microplastics in large mesocosms over a period of more than three months. We measured the biomass and abundance of different trophic groups, as well as ecological functions such as nutrient availability and decomposition rate. To explore the mechanisms underlying potential community and ecosystem-level effects, we also performed behavioral assays focusing on locomotion parameters as a response variable in three species: Daphnia magna (zooplankton prey), Chaoborus flavicans larvae (invertebrate pelagic predator of zooplankton) and Asellus aquaticus (benthic macroinvertebrate), using water from the mesocosms. Our mesocosm results demonstrate that presence of microplastics governs the response in phytoplankton biomass, with a weak non-monotonic dose-response relationship due to the interaction between microplastics and fluoxetine. However, exposure to fluoxetine evoked a strong non-monotonic dose-response in zooplankton abundance and microbial decomposition rate of plant material. In the behavioral assays, the locomotion of zooplankton prey D. magna showed a similar non-monotonic response primarily induced by fluoxetine. Its predator C. flavicans, however, showed a significant non-monotonic response governed by both microplastics and fluoxetine. The behavior of the decomposer A. aquaticus significantly decreased at higher fluoxetine concentrations, potentially leading to reduced decomposition rates near the sediment. Our study demonstrates that effects observed upon short-term exposure result in more pronounced ecosystem-level effects following chronic exposure. [Display omitted] •Model-ecosystem design reveals fluoxetine and microplastic interaction effects.•Fluoxetine evokes a non-monotonic response in zooplankton and decomposition rate.•Microplastics governs the response in phytoplankton standing crop.•Behavioral assays reveal non-monotonic responses in zooplankton and invertebrates.