AUTHOR=Richon Camille , Gorgues Thomas , Paul-Pont Ika , Maes Christophe 

TITLE=Zooplankton exposure to microplastics at global scale: Influence of vertical distribution and seasonality

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.947309

DOI=10.3389/fmars.2022.947309

ISSN=2296-7745

ABSTRACT=Microplastics (MP) are ubiquitous contaminants in the ocean. Zooplankton are thus widely
exposed to MP ingestion. Here, we use a global coupled physical-biogeochemical model enriched
with a 3D representation of MP to assess the global zooplankton exposure to MP. As expected,
our results indicate that water MP concentration is highest in the surface layers of subtropical
gyres and coastal areas close to major MP sources, which is mostly due to floating MP, while
neutral MP contaminate the mesopelagic zone. Additionally, we showed that floating MP may
be also transported to the mesopelagic waters during the seasonal deepening of the mixed
layer depth. We then estimate zooplankton exposure to MP based on water MP concentrations,
plankton biomass and zooplankton grazing rate. Two main drivers lead to high zooplankton
exposure to MP: 1) high water MP contamination and 2) intense grazing activity. Seasonally,
re-stratification of surface waters may lead to MP vertical concentration coinciding with planktonic
blooms, thus increasing contamination risk.