title: Environmental selection of planktonic methanogens in permafrost thaw ponds.
abstract: The warming and thermal erosion of ice-containing permafrost results in thaw ponds that are strong emitters of methane to the atmosphere. Here we examined methanogens and other Archaea, in two types of thaw ponds that are formed by the collapse of either permafrost peat mounds (palsas) or mineral soil mounds (lithalsas) in subarctic Quebec, Canada. Using high-throughput sequencing of a hypervariable region of 16S rRNA, we determined the taxonomic structure and diversity of archaeal communities in near-bottom water samples, and analyzed the mcrA gene transcripts from two sites. The ponds at all sites were well stratified, with hypoxic or anoxic bottom waters. Their archaeal communities were dominated by Euryarchaeota, specifically taxa in the methanogenic orders Methanomicrobiales and Methanosarcinales, indicating a potentially active community of planktonic methanogens. The order Methanomicrobiales accounted for most of the mcrA transcripts in the two ponds. The Archaeal communities differed significantly between the lithalsa and palsa ponds, with higher alpha diversity in the organic-rich palsa ponds, and pronounced differences in community structure. These results indicate the widespread occurrence of planktonic, methane-producing Archaea in thaw ponds, with environmental selection of taxa according to permafrost landscape type.
authors: Département de Biologie, Centre d'études nordiques (CEN) and Takuvik Joint International Laboratory, Université Laval, Québec, QC G1V 0A6, Canada.|Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC G1V 0A6, Canada.
authors: Sophie
authors: S
authors: Crevecoeur
authors: Département de Biologie, Centre d'études nordiques (CEN) and Takuvik Joint International Laboratory, Université Laval, Québec, QC G1V 0A6, Canada.
authors: Warwick F
authors: WF
authors: Vincent
authors: Département de Biologie, Centre d'études nordiques (CEN) and Takuvik Joint International Laboratory, Université Laval, Québec, QC G1V 0A6, Canada.|Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC G1V 0A6, Canada.|Québec-Océan, Université Laval, Québec, QC G1V 0A6, Canada.
authors: Connie
authors: C
authors: Lovejoy
mesh_terms: D001105:Archaea / Q000235:genetics*; D002170:Canada; D002245:Carbon Dioxide / Q000032:analysis; D016000:Cluster Analysis; D019641:DNA, Archaeal / Q000235:genetics; D019605:Euryarchaeota / Q000235:genetics*; D006863:Hydrogen-Ion Concentration; D008697:Methane; D065946:Permafrost; D010802:Phylogeny; D010933:Plankton; D061005:Ponds; D011792:Quebec; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil; D012988:Soil Microbiology; D013696:Temperature; D014871:Water Microbiology
chemical_list: D019641:DNA, Archaeal; D012336:RNA, Ribosomal, 16S; D012987:Soil; D002245:Carbon Dioxide; D008697:Methane