National Oceanography Centre, European Way, Southampton, SO14 3ZH, UK.
Microb Ecol. 2012 Jan;63(1):139-48. doi: 10.1007/s00248-011-9952-2. Epub 2011 Oct 13.
Microbial community structure in the subtropical north-east Atlantic Ocean was compared between 2 years and variation attributed to environmental variables. Surface seawater communities were analysed by flow cytometry and fluorescence in situ hybridisation. Probes specific to Alphaproteobacteria, Cyanobacteria, Gammaproteobacteria and Bacteroidetes identified 67-100% of cells. Due to natural variation in the study region due to the occurrence of major currents and islands, data could not be pooled but were instead divided between distinct water masses. Community structure did not differ greatly around the Cape Verde Islands between sampling periods but varied substantially in the open ocean, suggesting different environmental perturbations favour specific bacterial groups. Wind speed varied significantly between years, with moderate to strong breeze in winter 2008 and gales in winter 2006 (8.9 ± 0.2 ms(-1) and 16.0 ± 0.4 ms(-1), respectively). Enhanced wind-driven turbulence was associated with domination by the SAR11 clade of Alphaproteobacteria, which were present at 2.4-fold in the abundance of Prochlorococcus (41.8 ± 1.6% cells, compared to 17.7 ± 7.1%). Conversely, the calmer conditions of 2008 seemed to favour Prochlorococcus (40.0 ± 1.2% cells). Prochlorococcus high-light adapted clade HLI were only numerous during wind-driven turbulence, whereas oligotrophic-adapted clade HLII dominated under calm conditions. Bacteroidetes were most prominent in turbulent conditions (9.5 ± 1.3% cells as opposed to 4.7 ± 0.3%), as were Synechococcus. In 2008, a considerable dust deposition event occurred in the region, which may have led to the substantial Gammaproteobacteria population (22.5 ± 4.0% cells compared to 4.6 ± 0.6% in 2006). Wind-driven turbulence may have a significant impact on microbial community structure in the surface ocean. Therefore, community change following dust storm events may be linked to associated wind in addition to dust-derived nutrients.
对 2 年间亚热带东北大西洋的微生物群落结构进行了比较，并归因于环境变量的变化。通过流式细胞术和荧光原位杂交分析了表层海水群落。针对 α 变形菌门、蓝细菌、γ 变形菌门和拟杆菌门的探针鉴定了 67-100%的细胞。由于该研究区域由于主要洋流和岛屿的存在而发生自然变化，因此无法对数据进行汇总，而是根据不同的水体进行划分。在采样期间，佛得角群岛周围的群落结构差异不大，但在开阔海域则有很大差异，这表明不同的环境干扰有利于特定的细菌群体。风速在不同年份之间差异显著，2008 年冬季的微风和强风分别为 8.9±0.2ms-1和 16.0±0.4ms-1。增强的风驱动湍流与α变形菌门 SAR11 群的主导地位有关，该群在聚球藻丰度上增加了 2.4 倍（41.8±1.6%的细胞，而 17.7±7.1%的细胞）。相反，2008 年较为平静的条件似乎有利于聚球藻（40.0±1.2%的细胞）。高光适应的聚球藻高亮度 clade HLI 仅在风驱动的湍流中大量存在，而贫营养适应的 clade HLII 在平静条件下占主导地位。在湍流条件下，拟杆菌门最为突出（9.5±1.3%的细胞，而 4.7±0.3%的细胞），而聚球藻也是如此。2008 年，该地区发生了一次大规模的尘埃沉降事件，这可能导致了大量的γ 变形菌门种群（22.5±4.0%的细胞，而 2006 年为 4.6±0.6%）。风驱动的湍流可能对海洋表面微生物群落结构产生重大影响。因此，尘埃暴事件后的群落变化可能与相关风以及尘埃衍生的养分有关。
