Chongqing Jiaotong University, Chongqing, 400074, China.
Chongqing Institute of Green and Intelligent Technology, Chongqing School of University of Chinese Academy of Sciences, Chinese Academy of Sciences, Chongqing, 400714, China.
Appl Microbiol Biotechnol. 2024 Dec;108(1):130. doi: 10.1007/s00253-023-12993-4. Epub 2024 Jan 15.
Although the Three Gorges Dam (TGD) is the world's largest hydroelectric dam, little is known about the spatial-temporal patterns and community assembly mechanisms of meio- and micro-eukaryotes and its two subtaxa (zooplankton and zoobenthos). This knowledge gap is particularly evident across various habitats and during different water-level periods, primarily arising from the annual regular dam regulation. To address this inquiry, we employed mitochondrial cytochrome c oxidase I (COI) gene-based environmental DNA (eDNA) metabarcoding technology to systematically analyze the biogeographic pattern of the three communities within the Three Gorges Reservoir (TGR). Our findings reveal distinct spatiotemporal characteristics and complementary patterns in the distribution of meio- and micro-eukaryotes. The three communities showed similar biogeographic patterns and assembly processes. Notably, the diversity of these three taxa gradually decreased along the river. Their communities were less shaped by stochastic processes, which gradually decreased along the longitudinal riverine-transition-lacustrine gradient. Hence, deterministic factors, such as seasonality, environmental, and spatial variables, along with species interactions, likely play a pivotal role in shaping these communities. Environmental factors primarily drive seasonal variations in these communities, while hydrological conditions, represented as spatial distance, predominantly influence spatial variations. These three communities followed the distance-decay pattern. In winter, compared to summer, both the decay and species interrelationships are more pronounced. Taken together, this study offers fresh insights into the composition and diversity patterns of meio- and micro-eukaryotes at the spatial-temporal level. It also uncovers the mechanisms behind community assembly in various environmental niches within the dam-induced river-reservoir systems. KEY POINTS: • Distribution and diversity of meio- and micro-eukaryotes exhibit distinct spatiotemporal patterns in the TGR. • Contribution of stochastic processes in community assembly gradually decreases along the river. • Deterministic factors and species interactions shape meio- and micro-eukaryotic community.
尽管三峡大坝（TGD）是世界上最大的水电站，但对于中微型真核生物及其两个亚类（浮游动物和底栖动物）的时空格局和群落组装机制知之甚少。这种知识差距在各种生境和不同水位期尤为明显，主要是由于每年定期的大坝调节。为了解决这个问题，我们采用线粒体细胞色素 c 氧化酶 I（COI）基因的环境 DNA（eDNA）宏条形码技术，系统分析了三峡水库（TGR）内三个群落的生物地理格局。我们的研究结果揭示了中微型真核生物的分布具有明显的时空特征和互补模式。三个群落表现出相似的生物地理格局和组装过程。值得注意的是，这三个类群的多样性沿着河流逐渐减少。它们的群落受随机过程的影响较小，而是沿着纵向河流-过渡-湖泊梯度逐渐减少。因此，确定性因素，如季节性、环境和空间变量以及物种相互作用，可能在塑造这些群落方面起着关键作用。环境因素主要驱动这些群落的季节性变化，而水文学条件，以空间距离表示，主要影响空间变化。这三个群落遵循距离衰减模式。在冬季，与夏季相比，衰减和物种相互关系更为明显。总之，本研究为中微型真核生物在时空水平上的组成和多样性模式提供了新的见解，并揭示了在大坝诱导的河流-水库系统中不同环境小生境中群落组装的机制。
