Functional structure of laminated microbial sediments from a supratidal sandy beach of the German Wadden Sea (St. Peter-Ording)
Functional structure of laminated microbial sediments from a supratidal sandy beach of the German Wadden Sea (St. Peter-Ording)
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DOI：
10.1016/j.seares.2013.08.001
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发表时间：
2014-01-01
影响因子：
2
通讯作者：
Hinrichs, Kai-Uwe
中科院分区：
文献类型：
--
作者：
Buehring, Solveig I.;Kamp, Anja;Hinrichs, Kai-Uwe
对于未经训练的人来说，层状微生物沉积物隐藏在一层薄薄的沙层中，存在于北海沿岸的潮上海滩中。栖息的微生物群落根据光、氧或硫化合物的垂直梯度进行自我组织。我们使用脂质生物标记方法对微生物群落的垂直分区进行了精细调查，并结合微传感器测量和 C-13 标记实验评估了生物地球化学过程。脂质生物标志物指纹图谱显示了蓝藻和硅藻在这些系统中的首要重要性，而异囊糖脂揭示了即使在 9 至 20 毫米深度也存在固氮蓝藻。整个系统中高丰度的鸟氨酸脂质 (OL) 可能来自硫酸盐还原菌，而 5 至 8 毫米之间的特征性 OL 谱可能表明存在紫色非硫细菌。通过实验研究微生物脂质的吸收，追踪了 C-13 标记的碳酸氢盐的命运，揭示了蓝细菌对于碳固定的首要重要性。然而，在更深的层中，紫硫细菌的摄取是明显的，并且通过将标记摄取到最深层的硫酸盐还原细菌的脂质中可以显示出密切的微生物耦合。在稍后时间点收集的沉积物岩心中的微传感器测量揭示了与生物标志物分析和标记实验相同的一般模式。氧气和 pH 微传感器剖面显示顶层有活跃的光合作用。从更深处扩散并在活性氧光合作用层下方减少的硫化物表明硫细菌的存在，例如使用硫化物代替水进行光合作用的缺氧光养生物。 (C) 2013 Elsevier B.V. 保留所有权利。
Hidden for the untrained eye through a thin layer of sand, laminated microbial sediments occur in supratidal beaches along the North Sea coast. The inhabiting microbial communities organize themselves in response to vertical gradients of light, oxygen or sulfur compounds. We performed a fine-scale investigation on the vertical zonation of the microbial communities using a lipid biomarker approach, and assessed the biogeochemical processes using a combination of microsensor measurements and a C-13-labeling experiment. Lipid biomarker fingerprinting showed the overarching importance of cyanobacteria and diatoms in these systems, and heterocyst glycolipids revealed the presence of diazotrophic cyanobacteria even in 9 to 20 mm depth. High abundance of ornithine lipids (OL) throughout the system may derive from sulfate reducing bacteria, while a characteristic OL profile between 5 and 8 mm may indicate presence of purple non-sulfur bacteria. The fate of C-13-labeled bicarbonate was followed by experimentally investigating the uptake into microbial lipids, revealing an overarching importance of cyanobacteria for carbon fixation. However, in deeper layers, uptake into purple sulfur bacteria was evident, and a close microbial coupling could be shown by uptake of label into lipids of sulfate reducing bacteria in the deepest layer. Microsensor measurements in sediment cores collected at a later time point revealed the same general pattern as the biomarker analysis and the labeling experiments. Oxygen and pH-microsensor profiles showed active photosynthesis in the top layer. The sulfide that diffuses from deeper down and decreases just below the layer of active oxygenic photosynthesis indicates the presence of sulfur bacteria, like anoxygenic phototrophs that use sulfide instead of water for photosynthesis. (C) 2013 Elsevier B.V. All rights reserved.