Peatlands are important players in climate change-biosphere feedbacks via long-term net carbon (C) accumulation in soil organic matter and as potential net C sources including the potent greenhouse gas methane (CH4). Interactions of climate, site-hydrology, plant community, and groundwater chemical factors influence peatland development and functioning, including C dioxide (CO2) and CH4 fluxes, but the role of microbial community composition is not well understood. To assess microbial functional and taxonomic dissimilarities, we used high throughput sequencing of the small subunit ribosomal DNA (SSU rDNA) to determine bacterial and archaeal community composition in soils from twenty North American peatlands. Targeted DNA metabarcoding showed that although Proteobacteria, Acidobacteria, and Actinobacteria were the dominant phyla on average, intermediate and rich fens hosted greater diversity and taxonomic richness, as well as an array of candidate phyla when compared with acidic and nutrient-poor poor fens and bogs. Moreover, pH was revealed to be the strongest predictor of microbial community structure across sites. Predictive metagenome content (PICRUSt) showed increases in specific genes, such as purine/pyrimidine and amino-acid metabolism in mid-latitude peatlands from 38 to 45° N, suggesting a shift toward utilization of microbial biomass over utilization of initial plant biomass in these microbial communities. Overall, there appears to be noticeable differences in community structure between peatland classes, as well as differences in microbial metabolic activity between latitudes. These findings are in line with a predicted increase in the decomposition and accelerated C turnover, and suggest that peatlands north of 37° latitude may be particularly vulnerable to climate change.

中文翻译：

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泥炭地微生物群落组成是由自然气候梯度驱动的。

泥炭地通过土壤有机质中的长期净碳（C）积累以及作为潜在的净碳源（包括潜在的温室气体甲烷（CH4）），在气候变化-生物圈反馈中扮演着重要角色。气候，现场水文学，植物群落和地下水化学因素之间的相互作用影响泥炭地的发育和功能，包括二氧化碳（CO2）和CH4通量，但微生物群落组成的作用尚不清楚。为了评估微生物的功能和分类学差异，我们使用了小亚基核糖体DNA（SSU rDNA）的高通量测序来确定来自20个北美泥炭地土壤中的细菌和古细菌群落组成。有针对性的DNA元条形码表明，尽管平均而言，变形杆菌，酸性杆菌和放线菌是优势菌群，与酸性和营养贫乏的和沼泽相比，中等和富fen的宿主具有更大的多样性和分类学丰富性，以及一系列候选门。此外，pH被认为是跨站点微生物群落结构的最强预测因子。预测性基因组含量（PICRUSt）显示，中纬度泥炭地中的特定基因（例如嘌呤/嘧啶和氨基酸代谢）从38 N升高至45°N，表明在这些微生物中，微生物生物质的利用已超过了初始植物生物质的利用微生物群落。总体而言，泥炭地类别之间的群落结构似乎存在明显差异，而纬度之间的微生物代谢活动也存在差异。