Sunlight is the most important environmental control on diel fluctuations in phytoplankton activity, and understanding diel microbial processes is essential to the study of oceanic biogeochemical cycles. Yet, little is known about the in situ temporal dynamics of phytoplankton metabolic activities and their coordination across different populations. We investigated diel orchestration of phytoplankton activity in photosynthesis, photoacclimation, and photoprotection by analyzing pigment and quinone distributions in combination with metatranscriptomes in surface waters of the North Pacific Subtropical Gyre (NPSG). We found diel cycles in pigment abundances resulting from the balance of their synthesis and consumption. These dynamics suggest that night represents a metabolic recovery phase, refilling cellular pigment stores, while photosystems are remodeled towards photoprotection during daytime. Transcript levels of genes involved in photosynthesis and pigment metabolism had synchronized diel expression patterns among all taxa, reflecting the driving force light imparts upon photosynthetic organisms in the ocean, while other environmental factors drive niche differentiation. For instance, observed decoupling of diel oscillations in transcripts and related pigments indicates that pigment abundances are modulated by environmental factors extending beyond gene expression/regulation reinforcing the need to combine metatranscriptomics with proteomics and metabolomics to fully understand the timing of these critical processes in situ.

阳光是对浮游植物活动昼夜波动的最重要的环境控制，了解昼夜微生物过程对于研究海洋生物地球化学循环至关重要。然而，人们对浮游植物代谢活动的原位时间动态及其在不同种群之间的协调知之甚少。我们通过分析色素和醌的分布以及北太平洋副热带环流 (NPSG) 地表水中的宏转录组，研究了浮游植物在光合作用、光适应和光保护中的活性。我们发现色素丰度的昼夜循环是由它们的合成和消耗的平衡引起的。这些动态表明，夜晚代表了一个新陈代谢恢复阶段，重新填充细胞色素储存，而光系统在白天被改造为光保护。参与光合作用和色素代谢的基因转录水平在所有分类群中具有同步的 diel 表达模式，反映了光赋予海洋光合生物的驱动力，而其他环境因素则驱动生态位分化。例如，观察到的转录本和相关色素中 diel 振荡的解耦表明色素丰度受到超出基因表达/调控的环境因素的调节，这加强了将宏转录组学与蛋白质组学和代谢组学相结合的必要性，以充分了解这些关键过程的原位时间。参与光合作用和色素代谢的基因转录水平在所有分类群中具有同步的 diel 表达模式，反映了光赋予海洋光合生物的驱动力，而其他环境因素则驱动生态位分化。例如，观察到的转录本和相关色素中 diel 振荡的解耦表明色素丰度受到超出基因表达/调控的环境因素的调节，这加强了将宏转录组学与蛋白质组学和代谢组学相结合的必要性，以充分了解这些关键过程的原位时间。参与光合作用和色素代谢的基因转录水平在所有分类群中具有同步的 diel 表达模式，反映了光赋予海洋光合生物的驱动力，而其他环境因素则驱动生态位分化。例如，观察到的转录本和相关色素中 diel 振荡的解耦表明色素丰度受到超出基因表达/调控的环境因素的调节，这加强了将宏转录组学与蛋白质组学和代谢组学相结合的必要性，以充分了解这些关键过程的原位时间。