Microplastics do not increase bioaccumulation of petroleum hydrocarbons in Arctic zooplankton but trigger feeding suppression under co-exposure conditions

Arctic sea ice has alarmingly high concentrations of microplastics (MPs). Additionally, sea ice reduction in the Arctic is opening new opportunities for the oil and maritime industries, which could increase oil pollution in the region. Yet knowledge of the effects of co-exposure to MPs and crude oil on Arctic zooplankton is lacking. We tested the influence of MPs (polyethylene, 20.7 mu m) on polycyclic aromatic hydrocarbon (PAH) bioaccumulation and oil toxicity in the key arctic copepod Calanus hyperboreus after exposure to oil with and without dispersant. Up to 30% of the copepods stopped feeding and fecal pellet production rates were reduced after co-exposure to oil (1 mu L L-1) and MPs (20 MPs mL(-1)). The PAH body burdenwas similar to 3 times higher in feeding than in non-feeding copepods. Copepods ingested both MPs and crude oil droplets. MPs did not influence bioaccumulation of PAHs in copepods or their fecal pellets, but chemical dispersant increased bioaccumulation, especially of >= 4 ring-PAHs. Our results suggest thatMPs do not act as vectors of PAHs in Arctic marine foodwebs after oil spills, but, at high concentrations (20 MPs mL(-1)), MPs can trigger behavioral stress responses (e.g., feeding suppression) to oil pollution in zooplankton. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The study revealed that Arctic sea ice has high concentrations of microplastics, and the reduction of sea ice in the Arctic opens up new opportunities for the oil and maritime industries, increasing the risk of oil pollution in the region. Copods exposed to microplastics and crude oil may exhibit behavioral stress responses, such as feeding suppression.