In the ocean, Bacillariophyta are one of the most successful protistan groups. Due to their considerable biogeochemical implications, diatom diversity, development, and seasonality have been at the center of research, specifically large-sized species. In comparison, nanoplanktonic diatoms are mostly disregarded from routine monitoring and are often underrepresented in genetic reference databases. Here, we identified and investigated the temporal dynamics of relevant nanodiatoms occurring in the Western English Channel (SOMLIT-Astan station). Coupling in situ and laboratory approaches, we revealed that nano-species from the genera Minidiscus and Thalassiosira are key components of the phytoplankton community that thrive in these coastal waters, but they display different seasonal patterns. Some species formed recurrent blooms whilst others were persistent year round. These results raise questions about their regulation in the natural environment. Over a full seasonal cycle at the monitoring station, we succeeded in isolating viruses which infect these minute diatoms, suggesting that these mortality agents may contribute to their control. Overall, our study points out the importance of considering nanodiatom communities within time-series surveys to further understand their role and fate in marine systems.

中文翻译：

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西英吉利海峡相关纳米浮游硅藻的多样性和动态。

在海洋中，芽孢杆菌是最成功的原生生物群之一。由于具有相当大的生物地球化学意义，硅藻的多样性、发展和季节性一直是研究的中心，特别是大型物种。相比之下，纳米浮游硅藻大多不受常规监测的影响，并且在遗传参考数据库中的代表性不足。在这里，我们确定并研究了发生在西英吉利海峡（SOMLIT-Astan 站）的相关纳米硅藻的时间动态。结合原位和实验室方法，我们发现来自 Minidiscus 和 Thalassiosira 属的纳米物种是在这些沿海水域繁衍生息的浮游植物群落的关键组成部分，但它们显示出不同的季节性模式。一些物种形成反复开花，而其他物种则全年持续。这些结果提出了关于它们在自然环境中的调节的问题。在监测站的一个完整的季节性周期中，我们成功地分离出感染这些微小硅藻的病毒，这表明这些致死因子可能有助于控制它们。总的来说，我们的研究指出了在时间序列调查中考虑纳米硅藻群落以进一步了解它们在海洋系统中的作用和命运的重要性。