The Variation of Microbial Communities in a Depth Profile of Peat in the Gahai Lake Wetland Natural Conservation Area

The Gahai Lake wetland natural conservation area in northwestern China includes peatland that has been accumulating over hundreds of years and is seldom disturbed by industry. Bacteria and archaea in peat soil, which is a reservoir for carbon and water, may influence its ecological function. The objective of this study was to obtain a clearer understanding of peat microbial ecology and its relationship to the environmental conditions of this area. Hence, the microbial community of the peatland ecosystem was investigated by sequencing bacterial and archaeal DNA extracted from samples collected at different peat depths. Results showed that in all samples the dominant bacterial phyla were <i>Proteobacteria</i> (relative abundance 0.39 ± 0.12) and <i>Chloroflexi</i> (0.16 ± 0.09), while the dominant archaeal phyla were Miscellaneous Crenarchaeotic Group (MCG) (0.62 ± 0.21) and <i>Euryarchaeota</i> (0.27 ± 0.16). The diversity and microbial community structure at deeper depths (90 and 120 cm below the peat surface) significantly differ from that at shallower depths (10, 30 and 50 cm deep). In contrast to the shallow layers, the deeper layers became more abundant in the bacterial phyla <i>Chloroflexi, Bacteroidetes</i>, Atribacteria, Aminicenantes, <i>Chlorobi</i>, TA06, Caldiserica and <i>Spirochaetae</i>; and in the archaeal phyla MCG and Miscellaneous Euryarchaeotic Group (MEG). This study revealed a significant shift in microbial community in peat between 50 cm and 90 cm deep, as probably influenced by the oxygen supply at different depths. Furthermore, new insights into the microbial taxa were obtained, thus providing a baseline for future studies of this peat ecosystem.

中国西北的尕海湖湿地自然保护区内，存在经数百年持续积累且极少受工业活动扰动的泥炭地。作为碳与水的储库，泥炭土壤中的细菌和古菌可能对其生态功能产生影响。本研究旨在更清晰地阐明该区域泥炭微生物生态学特征及其与当地环境条件的关联。为此，研究人员对不同泥炭深度采集的样本中提取的细菌与古菌DNA进行测序，以此探究该泥炭地生态系统的微生物群落组成。
测序结果显示，所有样本中的优势细菌菌门为变形菌门（Proteobacteria，相对丰度0.39 ± 0.12）和绿弯菌门（Chloroflexi，0.16 ± 0.09）；优势古菌菌门则为奇古菌簇杂类群（Miscellaneous Crenarchaeotic Group, MCG，0.62 ± 0.21）以及广古菌门（Euryarchaeota，0.27 ± 0.16）。泥炭地表层以下90cm和120cm的深层样品，其微生物多样性与群落结构与浅层（10cm、30cm、50cm）样品存在显著差异。与浅层土层相比，深层土层中细菌菌门的绿弯菌门、拟杆菌门（Bacteroidetes）、Atribacteria、Aminicenantes、绿菌门（Chlorobi）、TA06、Caldiserica以及螺旋体门（Spirochaetae），以及古菌菌门的MCG和广古菌簇杂类群（Miscellaneous Euryarchaeotic Group, MEG）的相对丰度显著升高。
本研究揭示了泥炭层在50cm至90cm深度处发生的微生物群落显著转变，该转变或受不同深度的氧气供给条件影响。此外，本研究还获得了关于该区域微生物类群的新认知，为后续该泥炭生态系统的相关研究提供了基准参考数据。