title: Dynamics of ammonia-oxidizing Archaea and Bacteria in contrasted freshwater ecosystems.
abstract: Thaumarchaeota have been recognized as the main drivers of aerobic ammonia oxidation in many ecosystems. However, little is known about the role of ammonia-oxidizing Archaea (AOA) and Bacteria (AOB) in lacustrine ecosystems. In this study, the photic zone of three contrasted freshwater ecosystems located in France was sampled during two periods: winter homothermy (H) and summer thermal stratification (TS), to investigate the distribution of planktonic AOA and AOB. We showed that AOB were predominant in nutrient-rich ecosystems, whereas AOA dominated when ammonia concentrations were the lowest and during winter, which could provide a favorable environment for their growth. Moreover, analyses of archaeal libraries revealed the ubiquity of the thaumarchaeal I.1a clade associated with higher diversity of AOA in the most nutrient-poor lake. More generally, this work assesses the presence of AOA in lakes, but also highlights the existence of clades typically associated with lacustrine and hot spring ecosystems and specific ecological niches occupied by these microorganisms.
authors: Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes: Génome et Environnement, BP 10448, F-63000 Clermont-Ferrand, France.
authors: Mylène
authors: M
authors: Hugoni
authors: Sandrine
authors: S
authors: Etien
authors: Antoine
authors: A
authors: Bourges
authors: Cécile
authors: C
authors: Lepère
authors: Isabelle
authors: I
authors: Domaizon
authors: Clarisse
authors: C
authors: Mallet
authors: Gisèle
authors: G
authors: Bronner
authors: Didier
authors: D
authors: Debroas
authors: Isabelle
authors: I
authors: Mary
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001105:Archaea / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D058448:Biota; D005602:France; D005618:Fresh Water / Q000382:microbiology*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D012621:Seasons; D017422:Sequence Analysis, DNA
chemical_list: D000641:Ammonia