Heavy metals, organic chemicals, microplastics - how sensitive is zooplankton to pollution?

Abstract

Marine zooplankton encounter pollution from a multitude of land- and sea-based human activities through agricultural runoff, wastewater inputs, and industrial emissions. In addition, long-range transported airborne pollutants eventually enter the oceans through rainfall or dust fallout, and reach otherwise untouched remote areas, such as islands and the polar regions. The toxicity of chemical pollutants, including heavy metals, petrochemicals and pesticides, to zooplankton has been studied since the 1970s, and persistent organic pollutants (POPs), PFAS, and nanomaterials have since been added to the body of scientific literature. Recently, investigations of microplastics and microfibers add a layer of complexity, where both the physical traits of the particle and the chemical traits of leachable additives or adsorbed hydrophobic chemicals may drive the toxicity of these particulate contaminants. Here, I review examples of zooplankton-pollutant interactions for microplastics, car tire additives, and heavy metals studied with different approaches ranging from laboratory experiments, field sampling in combination with modeling efforts, to theoretical trait-based approaches. The individual phenotypic variability and species-specific patterns of sensitivity or resilience that emerge call for autecological assessments of vulnerability to pollution against the backdrop of changes in ocean climate, such as warming and ocean acidification. The multitude of pressures acting simultaneously demonstrates the urgent need to take multi-stress conditions and cocktail effects into account to understand and predict the anthropogenic impacts on marine zooplankton.