Assessment of Microplastic Size Range and Ingestion Intensity by Gmelinoides fasciatus Stebbing, an Invasive Species of Lake Onego

Abstract

To indicate the potential role of Gmelinoides fasciatus, an invasive species of Lake Onego, in the inclusion of microplastics into food webs, several indicators were evaluated: its ability to ingest microplastics, the preferred size ranges, and the ingestion intensity. For this purpose, irregularly shaped polystyrene copolymer particles (acrylonitrile butadiene styrene plastics, artificially crushed) of four size classes (<50, 50-100, 100-250, >250 µm) were used. Gmelinoides fasciatus actively ingested microplastic particles, and in treatment with particles of 100-250 µm in size, the consumption rate was the highest. The crustaceans that survived the experiment ingested smaller particles than the deceased ones. Based on the size-frequency distributions of the ingested particles and the same in the suspension, crustaceans preferred smaller particles than those in suspension. The mean size of the ingested particles was 100 ± 5 µm. However, considering the actual concentration of microplastic fragments in the sediments of Lake Onego, in natural conditions, a negative effect of microplastic fragments on the G. fasciatus population is unlikely. At the same time, the ability of the invasive species G. fasciatus to consume microplastics and their active integration into the food webs of Lake Onego through consumption by fish can be considered reliable factors of the entry of microplastics in the fish of Lake Onego.