title: Salinity Affects the Composition of the Aerobic Methanotroph Community in Alkaline Lake Sediments from the Tibetan Plateau.
abstract: Lakes are widely distributed on the Tibetan Plateau, which plays an important role in natural methane emission. Aerobic methanotrophs in lake sediments reduce the amount of methane released into the atmosphere. However, no study to date has analyzed the methanotroph community composition and their driving factors in sediments of these high-altitude lakes (>4000 m). To provide new insights on this aspect, the abundance and composition in the sediments of six high-altitude alkaline lakes (including both freshwater and saline lakes) on the Tibetan Plateau were studied. The quantitative PCR, terminal restriction fragment length polymorphism, and 454-pyrosequencing methods were used to target the pmoA genes. The pmoA gene copies ranged 104-106per gram fresh sediment. Type I methanotrophs predominated in Tibetan lake sediments, with Methylobacter and uncultivated type Ib methanotrophs being dominant in freshwater lakes and Methylomicrobium in saline lakes. Combining the pmoA-pyrosequencing data from Tibetan lakes with other published pmoA-sequencing data from lake sediments of other regions, a significant salinity and alkalinity effect (P = 0.001) was detected, especially salinity, which explained ∼25% of methanotroph community variability. The main effect was Methylomicrobium being dominant (up to 100%) in saline lakes only. In freshwater lakes, however, methanotroph composition was relatively diverse, including Methylobacter, Methylocystis, and uncultured type Ib clusters. This study provides the first methanotroph data for high-altitude lake sediments (>4000 m) and shows that salinity is a driving factor for the community composition of aerobic methanotrophs.
authors.affiliation: College of Geographic Sciences, Nanjing Normal University, 1 Wenyuan Road, 210023, Nanjing, China.|Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Straße 10, 35043, Marburg, Germany.|Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, 1 Wenyuan Road, 210023, Nanjing, China.
authors.forename: Yongcui
authors.initials: Y
authors.lastname: Deng
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, 100085, Beijing, China. yqliu@itpcas.ac.cn.
authors.forename: Yongqin
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
authors.forename: Marc
authors.initials: M
authors.lastname: Dumont
authors.affiliation: Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Straße 10, 35043, Marburg, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Conrad
mesh_terms: D044822:Biodiversity; D004269:DNA, Bacterial / Q000235:genetics; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology*; D060106:Lakes / Q000737:chemistry* / Q000382:microbiology*; D008697:Methane / Q000378:metabolism*; D020580:Methylobacterium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D008772:Methylococcaceae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D042083:Methylocystaceae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D054712:Salinity; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000378:metabolism*; D018609:Tibet
chemical_list: D004269:DNA, Bacterial; D012965:Sodium Chloride; D010088:Oxidoreductases; D008697:Methane
keywords: Aerobic methanotrophs; High-altitude lake; Methylomicrobium; Salinity; Tibetan Plateau