Orta-Ponce Cessna-Pamela, Alba-Salgueiro Rodrigo, Rodríguez Carlota, Valencia-Vila Joaquín, Díaz-Tapia Pilar, Bode Antonio, Nieto-Cid Mar, Varela Marta M
Facultade de Ciencias, Universidade da Coruña, A Coruña, Spain.
Centro Oceanográfico de A Coruña, Instituto Español de Oceanografía IEO-CSIC, A Coruña, Spain.
Environ Microbiol Rep. 2025 Aug;17(4):e70131. doi: 10.1111/1758-2229.70131.
Seasonality of prokaryotic abundance, diversity and community composition was investigated over a 2-year period in a coastal upwelling time-series station. A marked seasonality was found for prokaryotic abundance, peaking during upwelling and upwelling-to-downwelling transition, and decreasing during downwelling. The latter included a deeper mixed layer and a homogeneous water column favouring higher abundance of archaea (i.e., Marine Group II, Candiadatus nitrosopelagicus), SAR406 clade and the group Bacteria_Others including > 400 rare taxa. Upwelling and transition conditions, characterised by enhanced vertical stratification and a marked hydrographic variability, included a community less diverse with core-phylotypes proliferating, i.e., Flavobacteriaceae, Amylibacter and Planktomarina. Physical and biogeochemical variables collectively explained > 40% of the seasonal changes in prokaryotic assemblages. Additionally, fine-tune bacterial features evidenced 'closely related taxa' within particular bacterial phylotypes such as SAR116 clade; certain Flavobacteria belonging to NS2b, NS4 or NS9; members of the family Cryomorphaceae and Marine Group II, displaying seasonal microdiversity patterns. Taken together, seasonal hydrographic forcing induces a shift in the upwelling-driven microbiome providing new insights into the barely explored seasonal niche partitioning of surface prokaryotic communities in such highly productive upwelling systems. These results are of broad interest for understanding ecosystem functioning and forecast the impacts of current environmental change.
在一个沿海上升流时间序列站，对原核生物丰度、多样性和群落组成的季节性进行了为期两年的调查。发现原核生物丰度存在明显的季节性，在上升流期间以及从上升流向下沉流转变期间达到峰值，而在下沉流期间下降。下沉流包括一个更深的混合层和一个均匀的水柱，有利于古菌（即海洋第二类群、硝化螺旋菌属）、SAR406 进化枝以及包括 400 多个稀有分类单元的其他细菌类群的更高丰度。上升流和转变条件的特征是垂直分层增强和显著的水文变化，包括一个多样性较低的群落，核心系统型大量繁殖，即黄杆菌科、淀粉杆菌属和浮游海杆菌属。物理和生物地球化学变量共同解释了原核生物群落季节性变化的 40%以上。此外，精细调整的细菌特征证明了特定细菌系统型（如 SAR116 进化枝）内的“密切相关分类单元”；属于 NS2b、NS4 或 NS9 的某些黄杆菌；嗜冷杆菌科和海洋第二类群的成员，显示出季节性微多样性模式。总之，季节性水文强迫导致上升流驱动的微生物群落发生转变，为这种高产上升流系统中几乎未被探索的表层原核生物群落季节性生态位划分提供了新的见解。这些结果对于理解生态系统功能和预测当前环境变化的影响具有广泛的意义。
