Department of Biological, Geological and Environmental Sciences and Interdepartmental Research Centre for Environmental Sciences, UO CoNISMa, University of Bologna, Via S. Alberto 163, 48123, Ravenna, Italy.
Department of Biological, Geological and Environmental Sciences and Interdepartmental Research Centre for Environmental Sciences, UO CoNISMa, University of Bologna, Via S. Alberto 163, 48123, Ravenna, Italy; Department of Biology, Chioggia Hydrobiological Station Umberto D'Ancona, University of Padova, 30015, Chioggia, Italy.
Environ Pollut. 2020 Nov;266(Pt 2):115151. doi: 10.1016/j.envpol.2020.115151. Epub 2020 Jul 7.
Microplastics (MP) are omnipresent contaminants in the oceans, however little is known about the MP transfer between marine compartments and species. Three connected laboratory experiments using the filter-feeding mussel Mytilus galloprovincialis and the omnivorous polichaete Hediste diversicolor were conducted to evaluate whether the filtering action by mussels affects the vertical transfer of MP of different sizes (MP = 41 μm; MP = 129 μm) and densities (polyamide = 1.15 g cm; polypropylene = 0.92 g cm) across compartments and species with different feeding modes. Mussels significantly removed MP from the water column by incorporating them into biodeposits. This effect was particularly evident for the MP, whose deposition from the water column to the bottom was enhanced (about 15%) by the action of mussels. The incorporation of MP into faecal pellets increased the particles' sinking velocity by about 3-4 orders of magnitude. Conversely, the MP presence significantly decreased the depositional velocities of faecal pellets, and the magnitude of this effect was greater with increasing MP size and decreasing density. The MP incorporation into mussels' biodeposits also more than doubled the amount of MP uptake by H. diversicolor. We conclude that detrital pathways could be a transfer route of MP across marine compartments and food webs, potentially affecting the distribution of MP in sediments and creating hot-spots of bioavailable MP.
微塑料（MP）是海洋中普遍存在的污染物，但对于 MP 在海洋生物区系和物种之间的转移知之甚少。使用滤食贻贝 Mytilus galloprovincialis 和杂食性多毛类 Hediste diversicolor 进行了三个相互关联的实验室实验，以评估贻贝的过滤作用是否会影响不同大小（MP=41μm；MP=129μm）和密度（聚酰胺=1.15gcm；聚丙烯=0.92gcm）的 MP 在具有不同摄食方式的隔室和物种之间的垂直转移。贻贝通过将 MP 纳入生物沉积物中，从水柱中显著去除 MP。这种效果对于 MP 尤为明显，因为 MP 通过贻贝的作用从水柱沉积到底部的速度增加了（约 15%）。MP 纳入粪便颗粒会将颗粒的沉降速度提高约 3-4 个数量级。相反，MP 的存在显著降低了粪便颗粒的沉积速度，并且随着 MP 尺寸的增加和密度的降低，这种效果的幅度更大。MP 纳入贻贝的生物沉积物也使 H. diversicolor 对 MP 的吸收量增加了一倍以上。我们得出结论，碎屑途径可能是 MP 在海洋生物区系和食物网中转移的途径，可能会影响 MP 在沉积物中的分布并产生生物可利用 MP 的热点。
