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Abstract：
Predators ingest microplastics directly from the environment and indirectly via trophic transfer, yet studies have not investigated the contribution of each pathway to microplastic ingestion in fish. We assessed the relative importance of the two exposure routes using mysids (Neomysis spp.) and a benthic fish (Myoxocephalus brandti) as a model prey-predator system. We first exposed the mysids to fluorescent polyethylene beads (27-32 μm) at concentrations of 200 and 2000 μg/L. We then exposed the fish to water containing the same concentrations of polyethylene beads or to nine mysids pre-exposed to polyethylene beads. We quantified the size and overall mass of polyethylene beads in mysids and in fish to assess polyethylene beads fragmentation by the mysids. Mysids ingested 2-3 more polyethylene beads from water containing the higher concentration, and fish ingested 3-11 times more polyethylene beads via trophic transfer than from the water column. The percentage of fragmented particles was higher in mysids and in fish fed bead-exposed mysids, suggesting that the mysids can fragment polyethylene beads. Our experiments demonstrate that trophic transfer is a major route of microplastic ingestion by fish and that prey such as mysids can fragment microplastics. Small particles can translocate from the digestive system into tissues and exert adverse physiological effects. Trophic transfer of microplastics may therefore pose more serious threats to organisms at higher trophic levels.
摘要：
捕食者直接从环境中摄取微塑料，并通过营养转移间接摄取微塑料，然而，研究还没有调查每个途径对鱼类微塑料摄入的贡献。我们使用mysids评估了两种暴露途径的相对重要性（新菌病spp。）和底栖鱼类（Myoxocephalusbrandti）作为模型猎物-捕食者系统。我们首先将霉菌暴露于浓度为200和2000μg/L的荧光聚乙烯珠（27-32μm）。然后，我们将鱼暴露于含有相同浓度的聚乙烯珠的水中，或暴露于预先暴露于聚乙烯珠的九种霉菌。我们量化了霉菌和鱼中聚乙烯珠的大小和总质量，以评估霉菌引起的聚乙烯珠碎片。Mysids从含有较高浓度的水中摄取2-3个更多的聚乙烯珠，鱼通过营养转移摄取的聚乙烯珠子比从水柱摄取的聚乙烯珠子多3-11倍。在鱼肉中，破碎颗粒的百分比更高，在喂食珠子暴露的鱼肉中，这表明霉菌可以使聚乙烯珠破碎。我们的实验表明，营养转移是鱼类摄取微塑料的主要途径，并且诸如霉菌之类的猎物可以破坏微塑料。小颗粒可以从消化系统转移到组织中并产生不利的生理效应。因此，微塑料的营养转移可能对营养水平较高的生物构成更严重的威胁。
