聚球藻是海洋初级生产的重要贡献者，具有高度的系统发育多样性。然而，在中国最大的陆架海- -渤海，对其系统发育组成的研究还很缺乏。我们利用高通量测序技术对莱州湾( LZB )和渤海海峡( BS ) 6月和11月样品中的rpoC1基因进行了测序，以揭示渤海海湾和海峡地区聚球藻组合的系统发育组成。共鉴定出属于聚球藻亚簇S5.1、S5.2和S5.3的12个谱系。在空间上，分支I在BS中占据绝对主导地位。相比之下，LZB中的聚球藻组合更加多样化，分支VI和III比例较高。此外，我们在渤海海域6月至11月期间检测到强烈的聚球藻结构变化，分支 II、III、XX和miyav只在11月份被检测到。在垂直方向上，聚球藻群落的变化在水层之间并不明显，可能是由于水深较浅，水体混合强烈。冗余分析( RDA )和随机森林( RF )分析的结果共同强调了硅酸盐在聚球藻组合中的关键作用。我们的研究结果表明，渤海为聚球藻类群提供了特殊的生态位，导致聚球藻类群的系统发育组成与邻近的陆架海和世界其他大陆性海域相比具有独特性。

    Marine Synechococcus, a significant contributor to primary production, shows high phylogenetic diversity. However, studies on its phylogenetic composition in the Bohai Sea, the largest continental sea in China, are lacking. We sequenced rpoC1 (encodes the RNA polymerase beta' subunit protein) in samples from the Laizhou Bay (LZB) and Bohai Strait (BS) in June and November using high-throughput sequencing to reveal the phylogenetic composition of Synechococcus assemblages in the bay and strait areas of the Bohai Sea. In total, 12 lineages representing Synechococcus subclusters S5.1, S5.2, and S5.3 were identified. Spatially, clade I was obligately dominant in BS. In contrast, the Synechococcus assemblage in LZB was more diverse, with clades VI and III being highly abundant. In addition, we detected strong variation in Synechococcus structure between June and November in the Bohai Sea. Clades II, III, XX, and miyav were only detected in November. Vertically, variation in Synechococcus assemblage was not apparent among the water layers probably due to the shallow water depth with intense water mixing. Results of redundancy analysis (RDA) and random forest (RF) analysis together highlighted the key role of silicate in the Synechococcus assemblage. Our results suggested that the Bohai Sea provides various niches for different Synechococcus clades, resulting in a special phylogenetic composition of the Synechococcus assemblage, compared with that in the adjacent shelf sea and other continental seas in the world.