CESAM and Department of Biology, University of Aveiro, Aveiro, Portugal.
Antonie Van Leeuwenhoek. 2012 May;101(4):819-35. doi: 10.1007/s10482-012-9697-z. Epub 2012 Jan 19.
Bacterioneuston may play a key role in water-air exchange of gases and in processing organic matter and pollutants that accumulate at the sea-surface microlayer (SML). However, the phylogenetic diversity of bacterioneuston has been poorly characterized. We analyzed 24 samples each from the SML and underlying water (UW) at three sites in the Ria de Aveiro estuary, Portugal. Cultivation and culture-independent techniques were used to compare bacterioneuston and bacterioplankton. Culturable heterotrophic bacteria were enriched in the SML. The culturable community was dominated by Psychrobacter and Acinetobacter. The presence of high numbers of Psychrobacter was a notable result. Differences were confined to a few genera overrepresented in UW samples (Kocuria, Agrococcus and Vibrio). 16S rDNA DGGE profiles were highly stable in terms of number and position of bands between sampling sites and dates but cluster analysis revealed a slight tendency for grouping according to sampled layer. SML-specific DGGE bands affiliated with Actinobacteria, Cyanobacteria, Gammaproteobacteria and Bacteroidetes. Low similarity between nucleotide sequences of DGGE-bands and previously reported sequences suggest the occurrence of SML-specific populations. Enrichment of SML for Pseudomonas and Aeromonas was questioned and the diversity of both communities was analyzed. Consistent differences between SML and UW aeromonads communities were not identified. In terms of Pseudomonas, a culturable operational taxonomic unit was consistently overrepresented within SML samples. Taken together, our results indicate that the similarity between SML and UW communities depends on spatial and temporal factors.
细菌浮层可能在气体的水-气交换以及在处理海洋表面微层（SML）中积累的有机物质和污染物方面发挥关键作用。然而，细菌浮层的系统发育多样性尚未得到充分描述。我们从葡萄牙阿威罗河口的三个地点采集了每个 SML 和下层水（UW）的 24 个样本。我们使用培养和非培养技术来比较细菌浮层和细菌浮游生物。可培养的异养细菌在 SML 中得到了富集。可培养的群落主要由 Psychrobacter 和 Acinetobacter 组成。高数量的 Psychrobacter 的存在是一个显著的结果。差异仅限于 UW 样本中过度表达的少数属（Kocuria、Agrococcus 和 Vibrio）。16S rDNA DGGE 图谱在采样地点和日期之间的条带数量和位置方面非常稳定，但聚类分析显示出根据采样层分组的轻微趋势。SML 特异性 DGGE 条带与放线菌、蓝细菌、γ-变形菌和拟杆菌有关。DGGE 条带的核苷酸序列与先前报道的序列之间的低相似性表明存在 SML 特异性种群。对 SML 中 Pseudomonas 和 Aeromonas 的富集提出了质疑，并对这两个群落的多样性进行了分析。在 SML 和 UW 气单胞菌群落之间没有发现一致的差异。就 Pseudomonas 而言，可培养的操作分类单元在 SML 样本中始终过度表达。总的来说，我们的结果表明，SML 和 UW 群落之间的相似性取决于空间和时间因素。
