Contaminants disrupt aquatic food webs via decreased consumer efficiency


  • Overall, contaminants reduce consumption rates across aquatic ecosystems.
  • Contaminants disproportionately impact consumers relative to resource taxa.
  • Contaminants have greater negative effects on primary consumers with sedentary resources.
  • Metal contaminants have relatively strong dampening effects on consumption.
  • 33 % of studies expose contaminants to only consumer or resource, not both.


Changes in consumer-resource dynamics due to environmental stressors can alter energy flows or key interactions within food webs, with potential for cascading effects at population, community, and ecosystem levels. We conducted a meta-analysis to quantify the direction and magnitude of changes in consumption rates following exposure of consumer-resource pairs within freshwater-brackish and marine systems to anthropogenic CO2, heavy metals, microplastics, oil, pesticides, or pharmaceuticals. Across all contaminants, exposure generally decreased consumption rates, likely due to reduced consumer mobility or search efficiency. These negative effects on consumers appeared to outweigh co-occurring reductions in prey vigilance or antipredator behaviors following contaminant exposure. Consumption was particularly dampened in freshwater-brackish systems, for consumers with sedentary prey, and for lower-trophic-level consumers. This synthesis indicates that energy flow up the food web, toward larger – often ecologically and economically prized – taxa may be dampened as aquatic contaminant loads increase.

Clance L. R., Ziegler S. L. & Fodrie F. J., 2023. Contaminants disrupt aquatic food webs via decreased consumer efficiency. Science of the Total Environment 859(2): 160245. doi: 10.1016/j.scitotenv.2022.160245. Article.

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