Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique (GRIL), Université du Québec à Montréal, Montréal, QC, Canada.
Department of Marine Biology and Oceanography, Institut de Ciències del Mar (ICM-CSIC), Barcelona, Spain.
Mol Ecol. 2019 Sep;28(18):4181-4196. doi: 10.1111/mec.15223. Epub 2019 Sep 24.
Aerobic methanotrophic bacteria (methanotrophs) use methane as a source of carbon and energy, thereby mitigating net methane emissions from natural sources. Methanotrophs represent a widespread and phylogenetically complex guild, yet the biogeography of this functional group and the factors that explain the taxonomic structure of the methanotrophic assemblage are still poorly understood. Here, we used high-throughput sequencing of the 16S rRNA gene of the bacterial community to study the methanotrophic community composition and the environmental factors that influence their distribution and relative abundance in a wide range of freshwater habitats, including lakes, streams and rivers across the boreal landscape. Within one region, soil and soil water samples were additionally taken from the surrounding watersheds in order to cover the full terrestrial-aquatic continuum. The composition of methanotrophic communities across the boreal landscape showed only a modest degree of regional differentiation but a strong structuring along the hydrologic continuum from soil to lake communities, regardless of regions. This pattern along the hydrologic continuum was mostly explained by a clear niche differentiation between type I and type II methanotrophs along environmental gradients in pH, and methane concentrations. Our results suggest very different roles of type I and type II methanotrophs within inland waters, the latter likely having a terrestrial source and reflecting passive transport and dilution along the aquatic networks, but this is an unresolved issue that requires further investigation.
好氧甲烷营养菌（甲烷营养菌）将甲烷作为碳和能源的来源，从而减轻了自然来源的净甲烷排放。甲烷营养菌代表了一个广泛而系统发育复杂的群体，但该功能群的生物地理学以及解释甲烷营养菌群分类结构的因素仍知之甚少。在这里，我们使用高通量测序技术对细菌群落的 16S rRNA 基因进行测序，以研究甲烷营养菌群落组成以及影响其在广泛淡水生境（包括湖泊、溪流和河流）中分布和相对丰度的环境因素，这些淡水生境横跨北方景观。在一个区域内，还从周围流域采集土壤和土壤水样，以覆盖整个陆地-水生连续体。无论在哪个区域，北方景观的甲烷营养菌群落组成仅表现出适度的区域分化，但沿着从土壤到湖泊群落的水文连续体表现出强烈的结构，这一格局主要是由 pH 值和甲烷浓度等环境梯度上 I 型和 II 型甲烷营养菌之间明显的生态位分化所解释的。我们的研究结果表明，内陆水域中 I 型和 II 型甲烷营养菌的作用非常不同，后者可能具有陆地来源，反映了沿水网的被动运输和稀释，但这是一个尚未解决的问题，需要进一步研究。
