Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, 36310 Vigo, Spain. CSIC, Instituto de Investigacións Mariñas, Eduardo Cabello 6, 36208 Vigo, Spain. Scottish Association for Marine Science, Oban, Argyll PA37 1QA, UK.
Environ Microbiol Rep. 2009 Dec;1(6):545-54. doi: 10.1111/j.1758-2229.2009.00079.x. Epub 2009 Sep 23.
Microbial degradation of dissolved organic matter (DOM) in planktonic ecosystems is carried out by diverse prokaryotic communities, whose growth rates and patterns of DOM utilization modulate carbon and nutrient biogeochemical cycles at local and global scales. Nine dilution experiments (September 2007 to June 2008) were conducted with surface water from the highly productive coastal upwelling system of the Ría de Vigo (NW Iberian Peninsula) to estimate bacterial growth rates of six relevant marine bacterial groups: Roseobacter, SAR11, Betaproteobacteria,Gammaproteobacteria, SAR86 and Bacteroidetes. Surprisingly, SAR11 dominated over the other bacterial groups in autumn, likely associated to the entry of nutrient-rich, DOC-poor Eastern North Atlantic Central Water (ENACW) into the embayment. Roseobacter and SAR11 showed significantly opposing growth characteristics. SAR11 consistently grows at low rates (range 0.19-0.71 day(-1) ), while Roseobacter has a high growth potential (range 0.70-1.64 day(-1) ). In contrast, Betaproteobacteria, Bacteroidetes, SAR86 and Gammaproteobacteria growth rates widely varied among experiments. Regardless of such temporal variability, mean SAR86 growth rate (range 0.1-1.4 day(-1) ) was significantly lower than that of Gammaproteobacteria (range 0.3-2.1 day(-1) ). Whereas the relative abundance of different bacterial groups showed strong correlations with several environmental variables, group-specific bacterial growth rates did not co-vary with ambient conditions. Our results suggest that different bacterial groups exhibit characteristic growth rates, and, consequently, distinct competitive abilities to succeed under contrasting environmental conditions.
浮游生态系统中溶解有机物质（DOM）的微生物降解是由多样化的原核生物群落进行的，其生长速率和 DOM 利用模式调节着当地和全球碳和营养元素生物地球化学循环。2007 年 9 月至 2008 年 6 月，在高生产力的伊比利亚半岛西北部的维哥湾沿海上升流系统进行了 9 项稀释实验，以估计 6 种相关海洋细菌群的细菌生长速率：玫瑰杆菌、SAR11、β变形菌、γ变形菌、SAR86 和拟杆菌。令人惊讶的是，SAR11 在秋季占主导地位，可能与富含营养物质、DOM 贫化的东北大西洋中央水（ENACW）进入海湾有关。玫瑰杆菌和 SAR11 的生长特征明显相反。SAR11 的生长速度始终较低（范围为 0.19-0.71 天（-1）），而玫瑰杆菌的生长潜力较高（范围为 0.70-1.64 天（-1））。相比之下，β变形菌、拟杆菌、SAR86 和γ变形菌的生长速率在实验中差异较大。尽管存在这种时间变异性，但 SAR86 的平均生长速率（范围为 0.1-1.4 天（-1））明显低于γ变形菌（范围为 0.3-2.1 天（-1））。虽然不同细菌群的相对丰度与多个环境变量强烈相关，但特定于群的细菌生长速率与环境条件不一致。我们的结果表明，不同的细菌群表现出特征性的生长速率，因此在不同的环境条件下具有不同的竞争能力。
