Small thaw ponds: An unaccounted source of methane in the Canadian high Arctic.

Negandhi, Karita; Laurion, Isabelle; Whiticar, Michael J.; Galand, Pierre E.; Xu, Xiaomei et Lovejoy, Connie (2013). Small thaw ponds: An unaccounted source of methane in the Canadian high Arctic. PLoS ONE , vol. 8 , nº 11. e78204. DOI: 10.1371/journal.pone.0078204.

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Résumé

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.

Type de document:	Article
Mots-clés libres:	Arctic regions; Canada; carbon dioxide; genes, archaeal; global warming; methane; methanobacterium; molecular typing
Centre:	Centre Eau Terre Environnement
Date de dépôt:	09 avr. 2018 19:35
Dernière modification:	27 nov. 2019 14:20
URI:	https://espace.inrs.ca/id/eprint/3731

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