Data_Sheet_1_Ingestion and Depuration of Microplastics by a Planktivorous Coral Reef Fish, Pomacentrus amboinensis.docx

Microplastics are ubiquitous contaminants in marine environments and organisms. Concerns about potential impacts on marine organisms are usually associated with uptake of microplastics, especially via ingestion. This study used environmentally relevant exposure conditions to investigate microplastic ingestion and depuration kinetics of the planktivorous damselfish, Pomacentrus amboinensis. Irregular shaped blue polypropylene (PP) particles (longest length 125–250 μm), and regular shaped blue polyester (PET) fibers (length 600–700 μm) were selected based on physical and chemical characteristics of microplastics commonly reported in the marine environment, including in coral reef ecosystems. Individual adult damselfish were exposed to a single dose of PP particles and PET fibers at concentrations reported for waters of the Great Barrier Reef (i.e., environmentally relevant concentrations, ERC), or future projected higher concentrations (10x ERC, 100x ERC). Measured microplastic concentrations were similar to their nominal values, confirming that PP particles and PET fibers were present at the desired concentrations and available for ingestion by individual damselfish. Throughout the 128-h depuration period, the 88 experimental fish were sampled 2, 4, 8, 16, 32, 64, and 128-h post microplastic exposure and their gastrointestinal tracts (GIT) analyzed for ingested microplastics. While damselfish ingested both experimental microplastics at all concentrations, body burden, and depuration rates of PET fibers were significantly larger and longer, respectively, compared to PP particles. For both microplastic types, exposure to higher concentrations led to an increase in body burden and lower depuration rates. These findings confirm ingestion of PP particles and PET fibers by P. amboinensis and demonstrate for the first time the influence of microplastic characteristics and concentrations on body burden and depuration rates. Finally, despite measures put in place to prevent contamination, extraneous microplastics were recovered from experimental fish, highlighting the challenge to completely eliminate contamination in microplastic exposure studies. These results are critical to inform and continuously improve protocols for future microplastics research, and to elucidate patterns of microplastic contamination and associated risks in marine organisms.

微塑料是海洋环境与海洋生物体内普遍存在的污染物。学界对微塑料可能造成海洋生物损害的相关担忧，通常与生物对微塑料的摄取过程紧密相关，尤以经口摄入途径最为显著。本研究采用贴合自然环境的暴露实验条件，探究浮游食性鱼类安邦雀鲷（Pomacentrus amboinensis）对微塑料的摄入与净化动力学过程。研究选取两类在海洋环境（包括珊瑚礁生态系统）中常见报道的微塑料：形态不规则的蓝色聚丙烯（PP）颗粒（最长粒径125~250 μm），以及形态规整的蓝色聚酯（PET）纤维（长度600~700 μm），选取依据为这类微塑料的典型理化特征。将成年安邦雀鲷个体分别暴露于单剂量的PP颗粒与PET纤维中，暴露浓度采用大堡礁海域已报道的环境相关浓度（environmentally relevant concentrations, ERC），以及未来预测的更高浓度梯度（10倍ERC、100倍ERC）。实测微塑料浓度与理论标称值基本一致，证实PP颗粒与PET纤维可维持预设浓度，且可供安邦雀鲷个体摄食。在为期128小时的净化周期内，研究人员分别于微塑料暴露后2、4、8、16、32、64及128小时对88尾实验鱼进行取样，并对其胃肠道（GIT）内摄入的微塑料进行检测分析。尽管安邦雀鲷在所有浓度组中均可摄入两种实验微塑料，但与PP颗粒相比，PET纤维的体内负载量显著更高，净化速率也显著更慢。对于两种微塑料而言，暴露于更高浓度组均会导致体内负载量上升，且净化速率降低。本研究结果证实安邦雀鲷可摄入PP颗粒与PET纤维，并首次揭示了微塑料的理化特征与暴露浓度对其体内负载量及净化速率的影响。最后，尽管已采取相应措施避免外源污染，但仍从实验鱼体内检出了外源微塑料，这凸显了微塑料暴露研究中完全消除污染的难度。上述研究结果可为未来微塑料研究的实验方案优化提供重要参考，同时有助于阐明海洋生物体内微塑料污染的分布模式及其潜在生态风险。