College of Life Science and Technology, Jinan University, Guangzhou, China; College of Environment and Climate, Guangdong Provincial Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, Guangdong, China.
College of Life Science and Technology, Jinan University, Guangzhou, China.
Sci Total Environ. 2024 Nov 20;952:175986. doi: 10.1016/j.scitotenv.2024.175986. Epub 2024 Sep 2.
Microplastics have become ubiquitous in the global marine environment, posing substantial influences on marine organism health, food web function and marine ecosystem structure. Protozoan grazers are known for their ability to improve the biochemical constituents of poor-quality algae for subsequent use by higher trophic levels. However, the effects of microplastics on the trophic upgrading of protozoan grazers remain unknown. To address this knowledge gap, the ciliate Euplotes vannus and the heterotrophic dinoflagellate Oxyrrhis marina were exposed to microplastic particles (5 μm) for four days with various concentrations (1-20 mg/L). Both O. marina and E. vannus ingested microplastics. At the exposure level of 20 mg/L, the ingestion rate, growth rate, biovolume, and carbon biomass of E. vannus were significantly decreased by 28.18 %, 32.01 %, 30.46 %, and 82.27 %, respectively, while such effects were not observed for O. marina. The contents of highly unsaturated fatty acids in O. marina and E. vannus on a mixed diet of microplastic particles and green algae significantly reduced by 8.66 % and 41.49 % relative to feeding only on green algae, respectively. Besides, we also observed an increase in the composition of C18:3 (ω-3) and C20:3 (ω-3) concurrence with a significant decrease in C16:0 and C18:0 in E. vannus after 96 h exposure at 20 mg/L. These results indicate that microplastics can weaken trophic upgrading of the nutritional quality by protozoan grazers, which may consequently alter the function of food webs.
微塑料已在全球海洋环境中广泛存在，对海洋生物健康、食物网功能和海洋生态系统结构产生了重大影响。原生动物捕食者以能够改善低质量藻类的生化成分，从而使其更有利于更高营养级生物利用而闻名。然而，微塑料对原生动物捕食者的营养升级的影响尚不清楚。为了解决这一知识空白，我们将纤毛虫 E. vannus 和异养甲藻 O. marina 暴露于不同浓度（1-20 mg/L）的微塑料颗粒（5 μm）中 4 天。O. marina 和 E. vannus 都摄取了微塑料。在 20 mg/L 的暴露水平下，E. vannus 的摄食率、增长率、生物量和碳生物量分别显著降低了 28.18%、32.01%、30.46%和 82.27%，而 O. marina 则没有观察到这种影响。在混合微塑料颗粒和绿藻的饮食中，O. marina 和 E. vannus 中的高度不饱和脂肪酸含量分别显著降低了 8.66%和 41.49%，而单独以绿藻为食时则没有这种影响。此外，我们还观察到在 20 mg/L 暴露 96 小时后，E. vannus 中的 C18:3（ω-3）和 C20:3（ω-3）的组成增加，而 C16:0 和 C18:0 的含量显著降低。这些结果表明，微塑料可以削弱原生动物捕食者对营养质量的营养升级作用，从而可能改变食物网的功能。
