Microplastic Ingestion by Zooplankton

TLDR

Microplastics are ubiquitous in marine ecosystems and are known to be ingested by many marine organisms, yet their effects on zooplankton remain poorly understood. The study employed bioimaging and feeding‑rate experiments to document ingestion, egestion, and surface adherence of microplastics in northeast Atlantic zooplankton and to assess their impact on copepod algal ingestion. Thirteen zooplankton taxa ingested 1.7–30.6 µm polystyrene beads, with uptake varying by species, life stage, and bead size; copepods egested microplastic‑laden faecal pellets, microplastics adhered to their exteriors, and exposure to 7.3 µm particles reduced algal feeding in *Centropages typicus*, indicating that microplastics can impair zooplankton function and health.

Abstract

Small plastic detritus, termed "microplastics", are a widespread and ubiquitous contaminant of marine ecosystems across the globe. Ingestion of microplastics by marine biota, including mussels, worms, fish, and seabirds, has been widely reported, but despite their vital ecological role in marine food-webs, the impact of microplastics on zooplankton remains under-researched. Here, we show that microplastics are ingested by, and may impact upon, zooplankton. We used bioimaging techniques to document ingestion, egestion, and adherence of microplastics in a range of zooplankton common to the northeast Atlantic, and employed feeding rate studies to determine the impact of plastic detritus on algal ingestion rates in copepods. Using fluorescence and coherent anti-Stokes Raman scattering (CARS) microscopy we identified that thirteen zooplankton taxa had the capacity to ingest 1.7–30.6 μm polystyrene beads, with uptake varying by taxa, life-stage and bead-size. Post-ingestion, copepods egested faecal pellets laden with microplastics. We further observed microplastics adhered to the external carapace and appendages of exposed zooplankton. Exposure of the copepod Centropages typicus to natural assemblages of algae with and without microplastics showed that 7.3 μm microplastics (>4000 mL–1) significantly decreased algal feeding. Our findings imply that marine microplastic debris can negatively impact upon zooplankton function and health.