Given the biogeochemical functions of marine microbes, the structure and functional diversity of bacterioplankton communities could be regarded as bioindicators that reflect environmental quality. The habitat of the large yellow croaker (Pseudosciaena crocea) is suffering from widespread degradation, but the study of the croaker habitat is still insufficient. Here, we used 16S rRNA gene sequencing and functional prediction to investigate the surface bacterioplankton communities in an overwintering ground of P. crocea during the overwintering period (November 2018 to April 2019). Our results showed that the taxa and functions of the environmental bacterioplankton community exhibited obvious seasonality. Specifically, the bacterioplankton communities in autumn were characterized by animal parasites or symbionts, such as Acinetobacter baumannii and Moraxella, while organic substance–degrading bacteria, such as Rhodococcus, Stenotrophomonas, and Alcanivorax, dominated in spring. Moreover, phylogenetic-based mean nearest taxon distance (MNTD) analyses indicated that dispersal limitation was the most important process governing the spatiotemporal assembly of the bacterioplankton communities. The distance decay of similarity also suggested the impact of dispersal limitation on the generation of biogeographical patterns. Furthermore, variation partitioning analysis (VPA) and a partial Mantel test revealed that environmental filters, such as nutrients, temperature, and salinity, had relatively weak deterministic effects on the bacterioplankton community assembly. Overall, these findings provide a basis for understanding the theory of surface microbial community assembly in the overwintering habitat of the large yellow croaker.

中文翻译：

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东海南部大黄鱼Pseudosciaena crocea越冬栖息地表层浮游细菌群落的结构和功能多样性

鉴于海洋微生物的生物地球化学功能，浮游细菌群落的结构和功能多样性可被视为反映环境质量的生物指标。大黄鱼（Pseudosciaena crocea）的栖息地正在遭受广泛的退化，但对黄花鱼栖息地的研究仍然不足。在这里，我们使用 16S rRNA 基因测序和功能预测来调查大黄鱼越冬期间（2018 年 11 月至 2019 年 4 月）越冬地表面浮游细菌群落。我们的研究结果表明，环境浮游细菌群落的分类群和功能表现出明显的季节性。具体而言，秋季浮游细菌群落以动物寄生虫或共生体为特征，如鲍曼不动杆菌和莫拉氏菌，而有机物降解菌，如红球菌、狭养单胞菌和食肉菌则在春季占主导地位。此外，基于系统发育的平均最近分类距离 (MNTD) 分析表明，扩散限制是控制浮游细菌群落时空组装的最重要过程。相似性的距离衰减也暗示了扩散限制对生物地理模式产生的影响。此外，变异分区分析 (VPA) 和部分 Mantel 测试表明，环境过滤器，如营养物质、温度和盐度，对浮游细菌群落组装具有相对较弱的确定性影响。全面的，