Marine Ecology and Biodiversity Group: Plymouth Marine Laboratory, Plymouth PL1 3DH, UK; College of Life and Environmental Science: Biosciences, University of Exeter, Exeter EX4 4QP, UK.
College of Life and Environmental Science: Biosciences, University of Exeter, Exeter EX4 4QP, UK.
Sci Total Environ. 2019 Oct 15;687:780-789. doi: 10.1016/j.scitotenv.2019.06.009. Epub 2019 Jun 10.
Microplastics (1 μm-5 mm) are a ubiquitous marine contaminant of global concern, ingested by a wide range of marine taxa. Copepods are a key component of marine food webs, providing a source of food for higher trophic levels, and playing an important role in marine nutrient cycling. Microplastic ingestion has been documented in copepods, but knowledge gaps remain over how this affects feeding preference and faecal density. Here, we use exposure studies incorporating algal prey and microplastics of varying sizes and shapes at a concentration of 100 microplastics mL to show: (1) prey selection by the copepod Calanus helgolandicus was affected by the size and shape of microplastics and algae they were exposed to; Exposure to nylon fibres resulted in a 6% decrease in ingestion of similar shaped chain-forming algae, whilst exposure to nylon fragments led to an 8% decrease in ingestion of a unicellular algae that were similar in shape and size. (2) Ingestion of microplastics with different densities altered the sinking rates of faecal pellets. Faeces containing low-density polyethylene sank significantly more slowly than controls, whilst sinking rates increased when faeces contained high-density polyethylene terephthalate. These results suggest that C. helgolandicus avoid ingesting algae that are similar in size and/or shape to the microplastic particles they are exposed to, potentially in a bid to avoid consuming the plastic.
微塑料（1μm-5mm）是一种普遍存在的海洋污染物，受到全球关注，被广泛的海洋生物摄入。桡足类是海洋食物网的关键组成部分，为更高营养级别的生物提供了食物来源，并在海洋营养循环中发挥着重要作用。已经在桡足类中记录到了微塑料的摄入，但人们对这如何影响摄食偏好和粪便密度仍存在知识空白。在这里，我们使用暴露研究，将大小和形状不同的藻类和微塑料作为食物，浓度为 100 个微塑料/mL，结果表明：（1）桡足类 Calanus helgolandicus 的摄食偏好受到它们所接触的微塑料和藻类的大小和形状的影响；暴露于尼龙纤维会导致类似链状形成的藻类的摄入量减少 6%，而暴露于尼龙碎片会导致类似形状和大小的单细胞藻类的摄入量减少 8%。（2）不同密度的微塑料的摄入改变了粪便颗粒的沉降速率。低密度聚乙烯的粪便明显沉降速度较慢，而当粪便中含有高密度聚对苯二甲酸乙二醇酯时，沉降速度增加。这些结果表明，C. helgolandicus 避免摄入与它们接触的微塑料颗粒大小和/或形状相似的藻类，可能是为了避免摄入塑料。
