Walsh Emily A, Kirkpatrick John B, Rutherford Scott D, Smith David C, Sogin Mitchell, D'Hondt Steven
Department of Microbiology, The Forsyth Institute, Cambridge, MA, USA.
Harvard School of Dental Medicine, Boston, MA, USA.
ISME J. 2016 Apr;10(4):979-89. doi: 10.1038/ismej.2015.175. Epub 2015 Oct 2.
We investigated compositional relationships between bacterial communities in the water column and those in deep-sea sediment at three environmentally distinct Pacific sites (two in the Equatorial Pacific and one in the North Pacific Gyre). Through pyrosequencing of the v4-v6 hypervariable regions of the 16S ribosomal RNA gene, we characterized 450,104 pyrotags representing 29,814 operational taxonomic units (OTUs, 97% similarity). Hierarchical clustering and non-metric multidimensional scaling partition the samples into four broad groups, regardless of geographic location: a photic-zone community, a subphotic community, a shallow sedimentary community and a subseafloor sedimentary community (⩾1.5 meters below seafloor). Abundance-weighted community compositions of water-column samples exhibit a similar trend with depth at all sites, with successive epipelagic, mesopelagic, bathypelagic and abyssopelagic communities. Taxonomic richness is generally highest in the water-column O2 minimum zone and lowest in the subseafloor sediment. OTUs represented by abundant tags in the subseafloor sediment are often present but represented by few tags in the water column, and represented by moderately abundant tags in the shallow sediment. In contrast, OTUs represented by abundant tags in the water are generally absent from the subseafloor sediment. These results are consistent with (i) dispersal of marine sedimentary bacteria via the ocean, and (ii) selection of the subseafloor sedimentary community from within the community present in shallow sediment.
我们调查了太平洋三个环境不同地点（两个位于赤道太平洋，一个位于北太平洋环流）水柱中的细菌群落与深海沉积物中的细菌群落之间的组成关系。通过对16S核糖体RNA基因的v4 - v6高变区进行焦磷酸测序，我们对代表29,814个操作分类单元（OTU，97%相似度）的450,104个焦磷酸测序标签进行了特征分析。层次聚类和非度量多维标度分析将样本分为四大类，与地理位置无关：光合层群落、亚光合层群落、浅海沉积群落和海底以下沉积群落（海底以下⩾1.5米）。水柱样本的丰度加权群落组成在所有地点随深度呈现相似趋势，依次为上层浮游生物、中层浮游生物、深层浮游生物和深渊浮游生物群落。分类丰富度通常在水柱的氧最小值区最高，在海底以下沉积物中最低。在海底以下沉积物中由丰富标签代表的OTU在水柱中通常存在但由很少标签代表，而在浅海沉积物中由中等丰富标签代表。相反，在水中由丰富标签代表的OTU在海底以下沉积物中通常不存在。这些结果与以下两点一致：（i）海洋沉积细菌通过海洋扩散；（ii）从浅海沉积物中存在的群落中选择海底以下沉积群落。
