Georgia Institute of Technology, Schools of Biology and Earth & Atmospheric Sciences, Atlanta, Georgia, USA.
Appl Environ Microbiol. 2012 Oct;78(19):7023-31. doi: 10.1128/AEM.01750-12. Epub 2012 Jul 27.
The abundances, compositions, and activities of microbial communities were investigated at bog and fen sites in the Glacial Lake Agassiz Peatland of northwestern Minnesota. These sites contrast in the reactivity of dissolved organic matter (DOM) and the presence or absence of groundwater inputs. Microbial community composition was characterized using pyrosequencing and clone library construction of phylogenetic marker genes. Microbial distribution patterns were linked to pH, concentrations of dissolved organic carbon and nitrogen, C/N ratios, optical properties of DOM, and activities of laccase and peroxidase enzymes. Both bacterial and archaeal richness and rRNA gene abundance were >2 times higher on average in the fen than in the bog, in agreement with a higher pH, labile DOM content, and enhanced enzyme activities in the fen. Fungi were equivalent to an average of 1.4% of total prokaryotes in gene abundance assayed by quantitative PCR. Results revealed statistically distinct spatial patterns between bacterial and fungal communities. Fungal distribution did not covary with pH and DOM optical properties and was vertically stratified, with a prevalence of Ascomycota and Basidiomycota near the surface and much higher representation of Zygomycota in the subsurface. In contrast, bacterial community composition largely varied between environments, with the bog dominated by Acidobacteria (61% of total sequences), while the Firmicutes (52%) dominated in the fen. Acetoclastic Methanosarcinales showed a much higher relative abundance in the bog, in contrast to the dominance of diverse hydrogenotrophic methanogens in the fen. This is the first quantitative and compositional analysis of three microbial domains in peatlands and demonstrates that the microbial abundance, diversity, and activity parallel with the pronounced differences in environmental variables between bog and fen sites.
在明尼苏达州西北部的阿加西斯冰川泥炭地的沼泽和泉区对微生物群落的丰度、组成和活性进行了研究。这些地点在溶解有机物质（DOM）的反应性和地下水输入的存在与否方面存在差异。使用焦磷酸测序和系统发育标记基因的克隆文库构建来描述微生物群落组成。微生物分布模式与 pH 值、溶解有机碳和氮浓度、C/N 比、DOM 的光学特性以及漆酶和过氧化物酶活性有关。在泉区，细菌和古菌的丰富度和 rRNA 基因丰度平均比沼泽区高>2 倍，这与泉区 pH 值较高、可利用 DOM 含量较高以及酶活性增强一致。真菌的平均丰度相当于定量 PCR 检测的总原核生物的 1.4%。结果表明，细菌和真菌群落之间存在统计学上显著的空间分布模式。真菌的分布与 pH 值和 DOM 光学特性无关，并且呈垂直分层，在表面附近有较高的子囊菌和担子菌，在次表面有较高的接合菌。相比之下，细菌群落组成在环境之间差异较大，沼泽区以 Acidobacteria（总序列的 61%）为主，而泉区以 Firmicutes（52%）为主。与泉区中多种氢营养型甲烷菌的优势相比，沼泽区的乙酸营养型甲烷古菌表现出更高的相对丰度。这是首次对泥炭地中三个微生物域进行定量和组成分析，表明微生物丰度、多样性和活性与沼泽和泉区之间环境变量的显著差异平行。
