College of Marine Life Sciences, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.
College of Marine Life Sciences, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.
Chemosphere. 2021 Mar;267:129308. doi: 10.1016/j.chemosphere.2020.129308. Epub 2020 Dec 14.
Microplastic debris has become a significant global environmental issue. Yet, the effects on ingestion of microplastics by protozoan grazers-an important link in the microbial loop-are scant. Feeding experiments were conducted with the free-living marine ciliate Uronema marinum grazing on cultured bacteria Pseudoaltermonas sp., exposing them to different concentrations or sizes of polystyrene beads for 96 h. The number of beads decreased during exposure experiments. Under the microplastic influence, the ciliate cells were observed to decrease in abundance, body size, and biomass. It was noted that the ciliate biomass in the highest microplastic density treatment was significantly lower than that in the control (98.1% lower) and that microplastics can be ingested by ciliate protozoa which performed an important role in the transportation of energy across the microbial loop. Moreover, carbon biomass of ciliates exposed to microplastics of different particle diameters decreased significantly compared to the control. However, this effect does not seem to vary depending on microplastic sizes. This study is a first step in providing experimental insight into the feeding relationship between microplastics and marine protozoan grazers. Further research based on components of the microbial loop is needed to explore the impacts of microplastics in marine food webs.
微塑料碎片已成为全球性的重大环境问题。然而，原生动物食者（微生物环中的重要环节）摄入微塑料的影响却鲜为人知。本研究采用自由生活的海洋纤毛虫 Uronema marinum 摄食培养的细菌 Pseudoaltermonas sp.，进行了 96 小时的摄食实验，暴露于不同浓度或尺寸的聚苯乙烯珠中。暴露实验过程中，珠的数量减少。在微塑料的影响下，纤毛虫细胞的丰度、体型和生物量减少。值得注意的是，在最高微塑料密度处理组中，纤毛虫生物量明显低于对照组（低 98.1%），并且纤毛虫可以摄入在微生物环中具有重要能量传递作用的微塑料。此外，与对照组相比，暴露于不同粒径微塑料的纤毛虫的碳生物质显著降低。然而，这种影响似乎并不取决于微塑料的尺寸。本研究是深入了解微塑料与海洋原生动物食者之间摄食关系的第一步。需要进一步基于微生物环的成分进行研究，以探索微塑料对海洋食物网的影响。
