The cyanobacterium Prochlorococcus is the most abundant photosynthetic cell on Earth and contributes to global ocean carbon cycling and food webs. Prochlorococcus is known for its extensive diversity that falls into two groups of ecotypes, the low‐light (LL) and high‐light (HL) adapted ecotypes. Previous work has shown niche partitioning of the very abundant HL adapted ecotypes and subecotypes across oceanographic gradients including temperature, nutrients, and day length. However, niche partitioning of subecotypes within the LL adapted ecotypes has not been studied as well because they are less abundant and less accessible than surface, HL populations. Through high‐throughput, cyanobacterial‐specific, sequencing of high‐resolution depth profiles from three stations across the North Pacific Subtropical Front, we discovered extensive diversity and strong latitudinal partitioning of subecotype populations within LL ecotypes, in contrast to fairly consistent patterns at the broader level of LL Prochlorococcus ecotypes. These results indicate that both shallow and deep‐water processes shape microbial community structure in this region despite strong connectivity in microbial communities across the North Pacific Subtropical Front, supported by a few HL and LL sequences found ubiquitously across stations. This study expands understanding of the diversity and complexity of Prochlorococcus community structure over oceanographic gradients.

中文翻译：

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低光适应的原球菌亚亚型在北太平洋亚热带锋面海洋梯度上的生态位划分

蓝藻原球菌是地球上最丰富的光合细胞，并有助于全球海洋碳循环和食物网。原球菌以其广泛的多样性而著称，其分为两类生态型，即适应低光（LL）和高光（HL）的生态型。先前的工作表明，在包括温度，养分和天长在内的海洋梯度上，非常丰富的适应HL的生态型和亚生态型的生态位划分。但是，还没有研究过适应LL的生态型中亚生态型的生态位分配，因为它们比表层HL种群数量少，可及性差。通过北太平洋亚热带锋面三个站点的高通量，蓝藻特有的高分辨率深度剖面的测序，我们发现了LL生态型内亚生态型种群的广泛多样性和强大的纬度划分，而在更广泛的区域内却是一致的模式LL水平绿球菌生态型。这些结果表明，尽管整个北太平洋亚热带锋面的微生物群落之间具有很强的连通性，但浅水和深水过程仍在该区域形成了微生物群落结构，并在站点之间普遍存在一些HL和LL序列。这项研究扩大了对海洋梯度上Prochlorococcus群落结构的多样性和复杂性的了解。