Centre for Northern Studies (CEN) and Institut national de la recherche scientifique, Centre Eau Terre Environnement, Quebec, Canada.
PLoS One. 2013 Nov 13;8(11):e78204. doi: 10.1371/journal.pone.0078204. eCollection 2013.
Thawing permafrost in the Canadian Arctic tundra leads to peat erosion and slumping in narrow and shallow runnel ponds that surround more commonly studied polygonal ponds. Here we compared the methane production between runnel and polygonal ponds using stable isotope ratios, ¹⁴C signatures, and investigated potential methanogenic communities through high-throughput sequencing archaeal 16S rRNA genes. We found that runnel ponds had significantly higher methane and carbon dioxide emissions, produced from a slightly larger fraction of old carbon, compared to polygonal ponds. The methane stable isotopic signature indicated production through acetoclastic methanogenesis, but gene signatures from acetoclastic and hydrogenotrophic methanogenic Archaea were detected in both polygonal and runnel ponds. We conclude that runnel ponds represent a source of methane from potentially older C, and that they contain methanogenic communities able to use diverse sources of carbon, increasing the risk of augmented methane release under a warmer climate.
解冻的加拿大北极冻原导致泥炭侵蚀和坍塌，形成狭窄而浅的沟渠池塘，围绕着更为常见的多边形池塘。在这里，我们使用稳定同位素比、¹⁴C 标记和高通量测序古菌 16S rRNA 基因，比较了沟渠和多边形池塘之间的甲烷产生情况。我们发现，与多边形池塘相比，沟渠池塘的甲烷和二氧化碳排放量显著更高，而且来自于旧碳的比例略大。甲烷稳定同位素特征表明通过乙酸营养型甲烷生成，但在多边形和沟渠池塘中均检测到了乙酸营养型和氢营养型甲烷古菌的基因特征。我们得出结论，沟渠池塘代表了潜在更古老 C 的甲烷来源，并且它们包含能够利用多种碳源的产甲烷群落，这增加了在更温暖的气候下甲烷释放增加的风险。
