Hewson Ian, Jacobson Meyers Myrna E, Fuhrman Jed A
Department of Biological Sciences and Wrigley Institute for Environmental Studies, University of Southern California, 3616 Trousdale Pkwy AHF 107, Los Angeles, CA 90089-0371, USA.
Environ Microbiol. 2007 Apr;9(4):923-33. doi: 10.1111/j.1462-2920.2006.01214.x.
Sediment bacteria play important roles in the biogeochemistry of ocean sediments; however, factors influencing assemblage composition have not been extensively studied. We examined extractable sediment bacterial abundance, the composition of bacterial assemblages using a high-throughput molecular fingerprinting approach, and several sediment biogeochemical parameters (organic matter content and alkaline phosphatase activity), along a 35 km transect from Point Fermin, Southern California, to Santa Catalina Island, across the approximately 900-m-deep San Pedro Basin. Automated rRNA intergenic spacer analysis (ARISA) demonstrated that in two spatially isolated shallow (approximately < 60 m, on opposite sides of the channel) sediment environments, assemblages were more similar to each other than to deeper communities. Distinct communities existed in deeper and shallower sediments, and stations within the deep basin over 2 km apart contained remarkably similar assemblage fingerprints. The relative contribution to total amplified DNA fluorescence of operational taxonomic units (OTUs) was significantly correlated to that of other OTUs in few comparisons (2.7% of total), i.e. few bacterial types were found together or apart consistently. The relative proportions within assemblages of only a few OTU were significantly correlated to measured physicochemical parameters (organic matter content and wet/dry weight ratio of sediments) or enzyme (alkaline phosphatase) activities. A low percentage of shared OTU between shallow and deep sediments, and the presence of similar, but spatially isolated assemblages suggests that bacterial OTU may be widely dispersed over scales of a few kilometres, but that environmental conditions select for particular assemblages.
沉积物细菌在海洋沉积物的生物地球化学过程中发挥着重要作用；然而，影响群落组成的因素尚未得到广泛研究。我们沿着从南加州费米恩角到圣卡塔利娜岛的35公里断面，跨越约900米深的圣佩德罗盆地，研究了可提取的沉积物细菌丰度、使用高通量分子指纹技术的细菌群落组成，以及几个沉积物生物地球化学参数（有机质含量和碱性磷酸酶活性）。自动rRNA基因间隔区分析（ARISA）表明，在两个空间隔离的浅海（约<60米，位于海峡两侧）沉积物环境中，群落彼此之间的相似性高于与深海群落的相似性。深海和浅海沉积物中存在不同的群落，深盆中相距2公里以上的站点具有显著相似的群落指纹。在少数比较（占总数的2.7%）中，操作分类单元（OTU）对总扩增DNA荧光的相对贡献与其他OTU的相对贡献显著相关，即很少有细菌类型始终共同出现或分开出现。只有少数OTU在群落中的相对比例与测量的物理化学参数（有机质含量和沉积物湿/干重比）或酶（碱性磷酸酶）活性显著相关。浅海和深海沉积物之间共享OTU的比例较低，以及存在相似但空间隔离的群落，这表明细菌OTU可能在几公里的尺度上广泛分布，但环境条件会选择特定的群落。
