title: Partitioning of Thaumarchaeota populations along environmental gradients in high mountain lakes.
abstract: We investigated the spatial distribution and diversity of ammonia-oxidizing Archaea (AOA) across gradients of pH, trophic status and altitude in a set of high mountain lakes (Limnological Observatory of the Pyrenees, north-east Spain). Both phylogeny- and taxonomy-based approaches revealed well-defined AOA community patterns with pH as the main potential driving environmental factor. The I.1a and SAGMGC-1 Thaumarchaeota clusters, and their potentially associated amoA gene variants (clusters Fresh 5 and Soil/Fresh 1, respectively) showed highest relative abundances in the most oligotrophic lakes. Euryarchaeota (i.e. HV-Fresh cluster, Methanomicrobiales and Thermoplasmatales) dominated in lakes with higher trophic status. Phylogenetic diversity (PD) in Pyrenean lakes was 1.5- to 2.3-fold higher than the PD from an equivalent number of globally distributed marine and soil sites. We observed segregated distributions for SAGMGC-1, preferentially distributed in the lakes with the lowest pH (< 5) and the highest nitrite concentration (> 0.12 μm), and I.1a in lakes with lower nitrite and dissolved organic carbon concentrations below 0.5 mg L(-1) . Overall, these results showed strong selection by local environmental conditions, unveiled new ecological niches for freshwater SAGMGC-1 in low pH oligotrophic lakes, and suggested specific and successful adaptations of planktonic archaea to the high mountain lakes landscape.
authors.affiliation: Limnological Observatory of the Pyrenees (LOOP) - Biogeodynamics & Biodiversity Group, Department of Continental Ecology, Centre d'Estudis Avançats de Blanes CEAB-CSIC, Girona, Spain.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Auguet
authors.forename: Emilio O
authors.initials: EO
authors.lastname: Casamayor
mesh_terms: D000531:Altitude; D000641:Ammonia / Q000378:metabolism; D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D044822:Biodiversity; D004783:Environmental Microbiology; D060106:Lakes / Q000737:chemistry / Q000382:microbiology*; D008969:Molecular Sequence Data; D009573:Nitrites / Q000032:analysis; D010802:Phylogeny; D012988:Soil Microbiology; D013030:Spain
chemical_list: D009573:Nitrites; D000641:Ammonia