Abstract：
Tire wear particles (TWPs) are a major source of environmental microplastic pollution which gradually settle and accumulate in sediments after entering the aquatic environment, which can affect the behaviors of benthic organisms. Bioturbation of benthic species could affect the fate, impacts and potential risks of TWPs by altering the properties and structure of sediments. Therefore, in this study, the effect of TWPs on the burrowing activity of Chinese mitten crab (Eriocheir sinensis) was investigated. In addition, the effects of crab bioturbation on the distribution of TWPs and their additives were studied. The combined effects of TWPs and crab bioturbation on the microbial communities in the sediments were also explored. The results of this study showed that both TWPs and the leachate significantly inhibited the burrowing activity of crabs. TWPs in the surface layer of sediments were re-distributed by crab bioturbation and enriched mainly in the sediments near the burrow walls. Meanwhile, the heavy metals (i.e., Zn, Ca, Mg, Ba and Al) used as additives during the tire production in the burrow walls significantly increased as the accumulation of TWPs near burrow walls. In this study, TWP exposure decreased the bacterial diversity and abundance, as well as the functional genes related to carbon and nitrogen cycling process, but crab bioturbation increased them in the sediments of burrow walls by constructing a unique habitat. However, after TWPs entering into burrows, they were significantly decreased in the sediments near the burrow walls like the effects of TWPs, suggesting the negative effects of TWPs could play a dominant role in this combined system. Overall, this study is important for evaluating the distribution and effects of TWP pollution in the sediment ecosystem under biological factors such as bioturbation.
摘要：
轮胎磨损颗粒（TWPs）是环境微塑料污染的主要来源，进入水生环境后逐渐在沉积物中沉积并积累。会影响底栖生物的行为。底栖物种的生物扰动可能会影响命运，通过改变沉积物的性质和结构对TWP的影响和潜在风险。因此,在这项研究中，研究了TWP对中华绒螯蟹（Eriocheirsinensis）挖洞活动的影响。此外,研究了河蟹生物扰动对TWPs及其添加剂分布的影响。还探讨了TWPs和螃蟹生物扰动对沉积物中微生物群落的联合影响。这项研究的结果表明，TWPs和渗滤液均显着抑制了螃蟹的穴居活动。沉积物表层的TWPs通过螃蟹生物扰动重新分布，并主要富集在洞穴壁附近的沉积物中。同时,重金属(即，Zn,Ca,Mg,Ba和Al）在轮胎生产过程中用作添加剂，随着TWP在洞穴壁附近的积累，在洞穴壁中显着增加。在这项研究中,TWP暴露降低了细菌的多样性和丰度，以及与碳和氮循环过程相关的功能基因，但是螃蟹的生物扰动通过建立独特的栖息地来增加它们在洞穴壁的沉积物中的含量。然而,在TWP进入洞穴后，它们在洞穴壁附近的沉积物中明显减少，就像TWP的影响一样，这表明TWP的负面影响可能在这个联合系统中起主导作用。总的来说,这项研究对于评估生物扰动等生物因素下TWP污染在沉积物生态系统中的分布和影响具有重要意义。
