Cobalamin (B12) is an essential cofactor that is exclusively synthesized by some prokaryotes while many prokaryotes and eukaryotes require an external supply of B12. The spatial and temporal availability of B12 is poorly understood in marine ecosystems. Field measurements of B12 along with a large set of ancillary biotic and abiotic factors were obtained during three oceanographic cruises in the NW Iberian Peninsula, covering different spatial and temporal scales. B12 concentrations were remarkably low (<1.5 pM) in all samples, being significantly higher at the subsurface Eastern North Atlantic Central Water than at shallower depths, suggesting that B12 supply in this water mass is greater than demand. Multiple regression models excluded B12 concentration as predictive variable for phytoplankton biomass or production, regardless of the presence of B12‐requiring algae. Prokaryote production was the best predictor for primary production, and eukaryote community composition was better correlated with prokaryote community composition than with nutritional resources, suggesting that biotic interactions play a significant role in regulating microbial communities. Interestingly, co‐occurrence network analyses based on 16S and 18S rRNA sequences allowed the identification of significant associations between potential B12 producers and consumers (e.g. Thaumarchaeota and Dynophyceae, or Amylibacter and Ostreococcus respectively), which can now be investigated using model systems in the laboratory.

中文翻译：

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北大西洋东部沿海到近海横断面的钴胺素和微生物浮游生物动力学

钴胺素 (B12) 是一种必需的辅因子，仅由一些原核生物合成，而许多原核生物和真核生物需要 B12 的外部供应。在海洋生态系统中，人们对 B12 的时空可用性知之甚少。在西北伊比利亚半岛的三个海洋航行期间，获得了 B12 以及大量辅助生物和非生物因素的实地测量，涵盖了不同的空间和时间尺度。所有样品中的 B12 浓度都非常低（<1.5 pM），在北大西洋东部中部水体的地下明显高于较浅的深度，这表明该水体中 B12 的供应量大于需求量。多元回归模型排除了 B12 浓度作为浮游植物生物量或产量的预测变量，无论是否存在需要 B12 的藻类。原核生物生产是初级生产的最佳预测因子，真核生物群落组成与原核生物群落组成的相关性比与营养资源的相关性更好，表明生物相互作用在调节微生物群落中起着重要作用。有趣的是，基于 16S 和 18S rRNA 序列的共现网络分析允许识别潜在的 B12 生产者和消费者之间的显着关联（例如奇异古菌和 Dynophyceae，或 表明生物相互作用在调节微生物群落中起着重要作用。有趣的是，基于 16S 和 18S rRNA 序列的共现网络分析允许识别潜在的 B12 生产者和消费者之间的显着关联（例如奇异古菌和 Dynophyceae，或 表明生物相互作用在调节微生物群落中起着重要作用。有趣的是，基于 16S 和 18S rRNA 序列的共现网络分析允许识别潜在的 B12 生产者和消费者（例如奇异古菌和 Dynophyceae，或Amylibacter和Ostreococcus），现在可以在实验室中使用模型系统进行研究。