The Impact of Polystyrene Microplastics on Feeding, Function and Fecundity in the Marine Copepod Calanus helgolandicus

Abstract

Microscopic plastic debris, termed “microplastics”, are of increasing environmental concern. Recent studies have demonstrated that a range of zooplankton, including copepods, can ingest microplastics. Copepods are a globally abundant class of zooplankton that form a key trophic link between primary producers and higher trophic marine organisms. Here we demonstrate that ingestion of microplastics can significantly alter the feeding capacity of the pelagic copepod Calanus helgolandicus. Exposed to 20 μm polystyrene beads (75 microplastics mL(–1)) and cultured algae ([250 μg C L(–1)) for 24 h, C. helgolandicus ingested 11% fewer algal cells (P = 0.33) and 40% less carbon biomass (P < 0.01). There was a net downward shift in the mean size of algal prey consumed (P < 0.001), with a 3.6 fold increase in ingestion rate for the smallest size class of algal prey (11.6–12.6 μm), suggestive of postcapture or postingestion rejection. Prolonged exposure to polystyrene microplastics significantly decreased reproductive output, but there were no significant differences in egg production rates, respiration or survival. We constructed a conceptual energetic (carbon) budget showing that microplastic-exposed copepods suffer energetic depletion over time. We conclude that microplastics impede feeding in copepods, which over time could lead to sustained reductions in ingested carbon biomass.

Microplastic exposure studies should be environmentally realistic

“…Exposure experiments, like the study of Sussarellu et al (1) recently published in PNAS, may provide such insights. However, the results of dose-response experiments must always be interpreted in light of environmental concentrations, and the experimental concentrations examined by Sussarellu et al (1) and several others (2)(3)(4)(5)(6)(7)(8) are orders-of-magnitude higher than those reported from field studies (Fig. 1).…”

The flip-or-flop boutique: Marine debris on the shores of St Brandon's rock, an isolated tropical atoll in the Indian Ocean

“…The impact of marine debris and microplastics (< 5 mm) in particular remains subject to investigation but there are indications of negative effects on biota, mediated by both the physical and chemical characteristics and composition of plastics and microplastics (e.g. Barnes et al, 2009;Watts et al, 2014;Cole et al, 2015;Hardesty et al, 2015). The potential of impacts of marine plastic debris on human health is also attracting attention (Seltenrich, 2015).…”

Marine microplastics spell big problems for future generations

“…Sediment-dwelling worms exposed to sediments contaminated with PVC microparticles had increased gut transit times and reduced lipid accumulation (8). Similarly, planktonic copepods exposed to micropolystyrene for prolonged periods had reduced food consumption, resulting in reduced reproductive output (9). They also showed a downward shift in their preference for algal prey, suggesting altered feeding behavior postcapture or postingestion.…”