The microbial response to environmental changes in coastal waters of the eastern Cantabrian Sea was explored for four years by analysing a broad set of environmental variables along with bacterial community metabolism and composition. A recurrent seasonal cycle emerged, consisting of two stable periods, characterized by low bacterial metabolic activity (winter) from October to March, and high bacterial metabolic activity (summer) from May to August. These two contrasting periods were linked by short transition periods in April (TA ) and September (TS ). The phylogenetic groups Alphaproteobacteria and Bacteroidetes were dominant during winter and summer respectively, and their recurrent alternation was mainly driven by the bloom of eukaryotic phytoplankton before TA and the bloom of prokaryotic phytoplankton before TS . Bacterial growth efficiency remained high and stable during the winter and summer periods but dropped during the two short transition periods. Our results suggest that bacterial growth efficiency should be considered a very resilient property that reflects different stages in the adaptation of the bacterial community composition to the environmental changes occurring throughout the seasonal cycle in this coastal ecosystem.

中文翻译：

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沿海水域细菌生长效率，代谢和群落组成的周期性季节性变化。

通过分析一系列广泛的环境变量以及细菌群落的代谢和组成，探索了坎塔布连海东部沿海地区微生物对环境变化的响应。出现了一个周期性的周期性循环，包括两个稳定的时期，其特征是10月至3月的细菌代谢活动较低（冬季）和5月至8月的细菌代谢活动较高（夏季）。这两个相反的时期与4月（TA）和9月（TS）的短暂过渡期联系在一起。进化细菌群在冬季和夏季分别占主导地位，其轮生交替主要是由TA之前的真核浮游植物的开花和TS之前的原核浮游植物的开花驱动的。在冬季和夏季，细菌的生长效率仍然很高且稳定，但在两个短暂的过渡时期却有所下降。我们的结果表明，细菌的生长效率应被认为是一种非常有弹性的特性，它反映了细菌群落组成适应整个沿海生态系统整个季节周期中发生的环境变化的不同阶段。