Experimental ingestion of microplastics in three common Antarctic benthic species

Abstract

Microplastics (MP) have spread to every corner of the globe, reaching remote areas like Antarctica. Recentstudies detected MP in marine environments, including biota. Benthic organisms suffer negative effects upon MPingestion, leading to impacts on their populations. To address the current knowledge gap on how Antarcticbenthic invertebrates interact with MP, we conducted an experiment exposing a bivalve (Aequiyoldia eightsii) andtwo ascidians (Cnemidocarpa verrucosa and Molgula pedunculata) to polyethylene microbeads (mb). Specimens ofeach species were exposed for 48 h to two different concentrations of microbeads, a low dose (100 mb/l) and ahigh dose (1000 mb/l), with the same proportion of four different microbead size fractions (Fine (10–20 μm),Small (45–53 μm), Medium (106–125 μm), and Large (850–1000 μm)). After exposure, all three species hadingested microbeads. Significant differences between doses were observed in A. eightsii and C. verrucosa but not inM. pedunculata. Both ascidians ingested microbeads of all size fractions, whereas the bivalve did not ingest thelargest microbeads. No significant differences were found between species in the number nor sizes of microbeadsingested. Minor variations between taxa may be attributed to the specific biology and anatomy of each species.Our study highlights the need for a deeper understanding of Antarctic benthic ecosystems, suggesting that theinteraction with MP is species-specific. We believe that this study provides a baseline for assessing MP pollutionin Antarctic benthic invertebrates and will help to inform policy-makers in protecting and preserving Antarcticmarine ecosystems from MP pollution.