■由于塑料的大量处理,海洋生态系统接受这种废物的很大一部分。微塑料(MPs)是尺寸小于5毫米的固体颗粒。在塑料聚合物中,聚苯乙烯(PS)是一种最常用的和废弃的。由于它的密度大于水的密度,它积聚在海洋沉积物中,可能影响底栖群落。这项研究调查了MP的摄入及其对沙滩小型动物群落的影响。小型动物是沉积食物网的基础和较高营养水平之间的重要营养联系,因此可能与MP及其相关化合物的营养转移有关。
■我们在海洋沉积物中以三种标称浓度(103、105、107颗粒/mL)孵育了不添加MP(对照)和被PSMP(1-µm)污染的处理的微观世界,九天,每三天收集一次的小型动物样本。在每个采样时间,小型动物被收集,量化和识别到更高的分类单元水平,在落射荧光显微镜下定量MP的摄入。
■除了Tardigrada,所有小型动物类群(线虫,Turbellarians,co足类,Nauplii,Acari和Gastrotricha)摄入MP。吸收是强烈的剂量依赖性,最高为107个颗粒/毫升,在105个颗粒/mL时非常低,在103个颗粒/mL时无法证明。线虫主要在肠道中积累MP;肠道中的MP丰度随孵育时间的增加而增加。在最低的MP浓度下,总的meiofauna密度和物种丰富度显着降低,而在最高浓度下,这些参数与对照非常相似。相比之下,在低MP浓度的处理中,Shannon-Wiener多样性和均匀度更高。然而,这些结果应谨慎解释,因为在较低的两种MP浓度下,小型动物的丰度较低.
■在最高MP浓度下,丰度,海滩小型动物群落的分类学多样性和群落结构没有受到显着影响,表明MP对小型动物的影响最微妙。然而,较低的MP浓度确实导致丰度和多样性的大幅下降,与以前在人口和社区层面的研究一致。虽然我们只能推测这种违反直觉的反应的潜在机制,结果表明,需要进一步的研究来更好地了解MP对海洋底栖群落的影响。
UNASSIGNED: Due to the copious disposal of plastics, marine ecosystems receive a large part of this waste. Microplastics (MPs) are solid particles smaller than 5 millimeters in size. Among the plastic polymers, polystyrene (PS) is one of the most commonly used and discarded. Due to its density being greater than that of water, it accumulates in marine sediments, potentially affecting benthic communities. This study investigated the ingestion of MP and their effect on the meiofauna community of a sandy beach. Meiofauna are an important trophic link between the basal and higher trophic levels of sedimentary food webs and may therefore be substantially involved in trophic transfer of MP and their associated compounds.
UNASSIGNED: We incubated microcosms without addition of MP (controls) and treatments contaminated with PS MP (1-µm) in marine sediments at three nominal concentrations (103, 105, 107particles/mL), for nine days, and sampled for meiofauna with collections every three days. At each sampling time, meiofauna were collected, quantified and identified to higher-taxon level, and ingestion of MP was quantified under an epifluorescence microscope.
UNASSIGNED: Except for Tardigrada, all meiofauna taxa (Nematoda, turbellarians, Copepoda, Nauplii, Acari and Gastrotricha) ingested MP. Absorption was strongly dose dependent, being highest at 107 particles/mL, very low at 105 particles/mL and non-demonstrable at 103 particles/mL. Nematodes accumulated MP mainly in the intestine; MP abundance in the intestine increased with increasing incubation time. The total meiofauna density and species richness were significantly lower at the lowest MP concentration, while at the highest concentration these parameters were very similar to the control. In contrast, Shannon-Wiener diversity and evenness were greater in treatments with low MP concentration. However, these results should be interpreted with caution because of the low meiofauna abundances at the lower two MP concentrations.
UNASSIGNED: At the highest MP concentration, abundance, taxonomic diversity and community structure of a beach meiofauna community were not significantly affected, suggesting that MP effects on meiofauna are at most subtle. However, lower MP concentrations did cause substantial declines in abundance and diversity, in line with previous studies at the population and community level. While we can only speculate on the underlying mechanism(s) of this counterintuitive response, results suggest that further research is needed to better understand MP effects on marine benthic communities.