Eukaryal and Archaeal Diversity in a Submerged Sinkhole Ecosystem Influenced by Sulfur-Rich, Hypoxic Groundwater
Eukaryal and Archaeal Diversity in a Submerged Sinkhole Ecosystem Influenced by Sulfur-Rich, Hypoxic Groundwater
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受富硫、缺氧地下水影响的水下天坑生态系统中的真核和古菌多样性
DOI：
10.1016/j.jglr.2010.02.014
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发表时间：
2010
影响因子：
4.5
通讯作者：
B. Biddanda
中科院分区：
文献类型：
--
作者：
S. Nold;Heidi A. Zajack;B. Biddanda
中岛天坑(23米深)是休伦湖(美国密苏里州)的一个水下岩溶地貌，充斥着低氧、高电导率的地下水。在这里，由紫色丝状蓝藻组成的微生物垫覆盖着富碳的沉积物。为了研究该生境中古细菌和真核生物的物种多样性，我们构建了克隆文库，并对沉积物岩心小亚单位核糖体RNA基因进行了测序，这些核糖体RNA基因被分成五个明显不同的层：表层蓝藻垫层(0-0.2 cm)，底层白色结晶层(0.2-0.5 cm)，以及从岩心不同层(0.5-2.0 cm，7.5-9.5 cm，24.5-28.5 cm)中选择的三个富含有机物质的黑色沉积物亚段。蓝藻的克隆文库以真核18S rRNA基因序列为主，如线虫(Tobrilus Gracilis)、纤毛虫(Frontonia Vernaris)和迟滞动物(Isohsibius Granifer)。浅层富含有机物质的沉积物与上覆垫层共享克隆，但也包括种子虾(Cyprdidae sp.)和桡足类(Leptodiaptomus spp.)来自最深沉积物的克隆库主要是与已知的产甲烷菌(甲烷螺菌和甲烷菌)相似的古生菌序列和包括非嗜热的克伦考古群在内的未培养的古生代。系统发育树显示了在不同的真核生物和古生物谱系中的代表性。通过记录淡水天坑的物种组成，这项研究扩大了我们对受低氧、富硫地下水影响的生境中微生物群落的了解。
Middle Island sinkhole (23m depth) is an underwater karst feature in Lake Huron (MI, USA) inundated with hypoxic, high-conductivity groundwater. Here, microbial mats composed of purple-pigmented filamentous cyanobacteria cover carbon-rich sediments. To study the species diversity of Archaea and Eukarya in this habitat, we constructed clone libraries and sequenced the small subunit ribosomal RNA genes from sediment cores sectioned into five visually distinct layers: the surface cyanobacterial mat (0–0.2cm), an underlying white crystalline layer (0.2–0.5cm), and three sub-sections of black organic-rich sediment chosen from distinct layers in the cores (0.5–2.0cm, 7.5–9.5cm, and 24.5–28.5cm). Clone libraries from the cyanobacterial mat were dominated by eukaryal 18S rRNA gene sequences such as nematodes (Tobrilus gracilis), ciliates (Frontonia vernalis), and tardigrades (Isohypsibius granulifer). Shallow organic-rich sediments shared clones with the overlying mat but also included seed shrimp (Cyprididae sp.) and copepods (Leptodiaptomus spp.). Clone libraries from the deepest sediments were dominated by archaeal sequences similar to known methanogens (Methanosphaerula and Methanosaeta) and uncultivated Archaea, including non-thermophilic Crenarchaeota. Phylogenetic trees revealed representation in diverse eukaryotic and archaeal lineages. By chronicling the species composition of freshwater sinkholes, this study expands our knowledge of microbial communities in habitats influenced by hypoxic, sulfur-rich groundwater.