Abstract：
Raphidiopsis blooms are notorious for cyanotoxin formation and strong invasiveness, threatening the stability of aquatic ecosystems and human health. The protozoa Paramecium can potentially serve as an organism for controlling Raphidiopsis blooms owing to its grazing effect. However, the grazing ability of Paramecium is largely determined by the size of the prey, and the population of Raphidiopsis consists of filaments of varying lengths and sizes. The selective grazing behavior of Paramecium toward short-length or small-sized filaments in the Raphidiopsis population, as opposed to long filaments, remains unclear. Therefore, in this study, we co-cultured the predator Paramecium sp. with different initial abundances and the prey Raphidiopsis raciborskii to explore this knowledge gap. Our results suggested that: (1) the population of R. raciborskii declined under the selective grazing effect of Paramecium sp. on short filaments, whereas R. raciborskii with long filaments survived; (2) the growth of Paramecium sp. feeding on the same abundance of R. raciborskii was reduced at higher initial abundances, whereas its carrying capacity exhibited an opposite trend; (3) under ingestion by Paramecium sp., the morphology of R. raciborskii developed in the direction of becoming larger, and higher initial abundances of Paramecium sp. intensified this process; (4) increasing initial abundance of Paramecium sp. aggravated the decline of R. raciborskii photosynthetic activity. Therefore, the grazing effect of Paramecium sp. on R. raciborskii mainly affects filaments of short length or small size. Collectively, these results clarify the inter-species interaction between the protozoa Paramecium and filamentous cyanobacteria Raphidiopsis, including population dynamics and morphological and physiological changes in the predator and prey. Such insights into the interactions between Paramecium and R. raciborskii may have implications for the biological control of blooms caused by filamentous cyanobacteria.
摘要：
Rephiopsis花臭名昭著的是蓝藻毒素的形成和强大的侵袭性，威胁着水生生态系统的稳定和人类健康。原生动物草履虫由于其放牧作用，可以作为一种控制菜鸟水华的生物。然而,草履虫的放牧能力在很大程度上取决于猎物的大小，Raphiopsis的种群由不同长度和大小的细丝组成。草履虫对短长度或小尺寸细丝的选择性放牧行为，与长细丝相反，尚不清楚。因此,在这项研究中，我们共同培养了捕食者草履虫。具有不同的初始丰度和猎物Rephidiopsisraciborskii来探索这种知识差距。我们的结果表明：（1）在草履虫的选择性放牧作用下，草履虫的种群数量下降。在短丝上，而长丝的raciborskii存活；（2）草履虫的生长。在较高的初始丰度下，以相同丰度的raciborskii为食减少，而其承载能力表现出相反的趋势；（3）被草履虫摄取。,raciborskii的形态向变大的方向发展，草履虫的初始丰度较高。加强了这一过程；（4）增加草履虫的初始丰度。加剧了raciborskii光合活性的下降。因此,草履虫的放牧效果。在raciborskii上，主要影响短长度或小尺寸的细丝。总的来说，这些结果阐明了原生动物草履虫和丝状蓝藻之间的种间相互作用，包括捕食者和猎物的种群动态以及形态和生理变化。对草履虫和raciborskii之间相互作用的这种见解可能对丝状蓝细菌引起的水华的生物控制具有意义。
