Specific Bacterial, Archaeal, and Eukaryotic Communities in Tidal-Flat Sediments along a Vertical Profile of Several Meters
Specific Bacterial, Archaeal, and Eukaryotic Communities in Tidal-Flat Sediments along a Vertical Profile of Several Meters
复制标题
DOI：
10.1128/aem.72.4.2756-2764.2006
复制
发表时间：
2006-04
影响因子：
4.4
通讯作者：
R. Wilms;H. Sass;B. Köpke;J. Köster;H. Cypionka;B. Engelen
中科院分区：
文献类型：
--
作者：
R. Wilms;H. Sass;B. Köpke;J. Köster;H. Cypionka;B. Engelen
摘要用分子和地球化学方法分析了深达360厘米的潮滩沉积物的次表层。利用结构域特异的聚合酶链式反应对所有三个生命领域的群落结构进行分析，然后进行变性梯度凝胶电泳分析和特征条带的测序。沉积柱由岩性容易区分的层位组成，这些层位沉积在潮间带和盐沼环境中。孔隙水剖面的特征是在约250厘米深度处有一个次表层硫酸盐峰。甲烷和硫酸盐剖面相反，显示无硫酸盐地层中甲烷浓度增加。有机碳的有效性似乎对深层沉积物中的细菌群落组成有最显著的影响。总体而言，细菌群落以发酵菌和合养细菌为主。产甲烷古菌的深度分布与硫酸盐剖面相关，可用硫酸盐还原细菌的电子供体竞争来解释。在无硫酸盐蛋鸡中存在与典型的氢遗传营养微生物甲烷杆菌相关的序列。在整个缺氧沉淀柱中都发现了属于甲烷类的古生菌，它们利用非竞争性底物。针对真核生物18S rRNA基因的引物显示，在沉积物岩芯的更深部分存在古生菌序列的子集。与其他古生物序列的系统发育距离表明，这些生物代表了一个新的系统发育群，被提出为“潮滩群1”。尽管它们的多样性随着深度的增加而减少，但在360厘米处仍然可以检测到真核生物。大多数真核序列与食草动物和沉积物捕食者的序列有较远的亲缘关系。
ABSTRACT The subsurface of a tidal-flat sediment was analyzed down to 360 cm in depth by molecular and geochemical methods. A community structure analysis of all three domains of life was performed using domain-specific PCR followed by denaturing gradient gel electrophoresis analysis and sequencing of characteristic bands. The sediment column comprised horizons easily distinguishable by lithology that were deposited in intertidal and salt marsh environments. The pore water profile was characterized by a subsurface sulfate peak at a depth of about 250 cm. Methane and sulfate profiles were opposed, showing increased methane concentrations in the sulfate-free layers. The availability of organic carbon appeared to have the most pronounced effect on the bacterial community composition in deeper sediment layers. In general, the bacterial community was dominated by fermenters and syntrophic bacteria. The depth distribution of methanogenic archaea correlated with the sulfate profile and could be explained by electron donor competition with sulfate-reducing bacteria. Sequences affiliated with the typically hydrogenotrophic Methanomicrobiales were present in sulfate-free layers. Archaea belonging to the Methanosarcinales that utilize noncompetitive substrates were found along the entire anoxic-sediment column. Primers targeting the eukaryotic 18S rRNA gene revealed the presence of a subset of archaeal sequences in the deeper part of the sediment cores. The phylogenetic distance to other archaeal sequences indicates that these organisms represent a new phylogenetic group, proposed as “tidal-flat cluster 1.” Eukarya were still detectable at 360 cm, even though their diversity decreased with depth. Most of the eukaryotic sequences were distantly related to those of grazers and deposit feeders.