title: pH as a Driver for Ammonia-Oxidizing Archaea in Forest Soils.
abstract: In this study, we investigated the impact of soil pH on the diversity and abundance of archaeal ammonia oxidizers in 27 different forest soils across Germany. DNA was extracted from topsoil samples, the amoA gene, encoding ammonia monooxygenase, was amplified; and the amplicons were sequenced using a 454-based pyrosequencing approach. As expected, the ratio of archaeal (AOA) to bacterial (AOB) ammonia oxidizers' amoA genes increased sharply with decreasing soil pH. The diversity of AOA differed significantly between sites with ultra-acidic soil pH (<3.5) and sites with higher pH values. The major OTUs from soil samples with low pH could be detected at each site with a soil pH <3.5 but not at sites with pH >4.5, regardless of geographic position and vegetation. These OTUs could be related to the Nitrosotalea group 1.1 and the Nitrososphaera subcluster 7.2, respectively, and showed significant similarities to OTUs described from other acidic environments. Conversely, none of the major OTUs typical of sites with a soil pH >4.6 could be found in the ultra- and extreme acidic soils. Based on a comparison with the amoA gene sequence data from a previous study performed on agricultural soils, we could clearly show that the development of AOA communities in soils with ultra-acidic pH (<3.5) is mainly triggered by soil pH and is not influenced significantly by the type of land use, the soil type, or the geographic position of the site, which was observed for sites with acido-neutral soil pH.
authors.affiliation: Environmental Genomics, Helmholtz Zentrum München, German Research Centre for Environmental Health, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Stempfhuber
authors.forename: Marion
authors.initials: M
authors.lastname: Engel
authors.forename: Doreen
authors.initials: D
authors.lastname: Fischer
authors.forename: Ganna
authors.initials: G
authors.lastname: Neskovic-Prit
authors.forename: Tesfaye
authors.initials: T
authors.lastname: Wubet
authors.forename: Ingo
authors.initials: I
authors.lastname: Schöning
authors.forename: Cécile
authors.initials: C
authors.lastname: Gubry-Rangin
authors.forename: Susanne
authors.initials: S
authors.lastname: Kublik
authors.forename: Brigitte
authors.initials: B
authors.lastname: Schloter-Hai
authors.forename: Thomas
authors.initials: T
authors.lastname: Rattei
authors.forename: Gerhard
authors.initials: G
authors.lastname: Welzl
authors.forename: Graeme W
authors.initials: GW
authors.lastname: Nicol
authors.forename: Marion
authors.initials: M
authors.lastname: Schrumpf
authors.forename: Francois
authors.initials: F
authors.lastname: Buscot
authors.forename: James I
authors.initials: JI
authors.lastname: Prosser
authors.forename: Michael
authors.initials: M
authors.lastname: Schloter
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001105:Archaea / Q000502:physiology*; D065928:Forests; D005858:Germany; D006863:Hydrogen-Ion Concentration; D064307:Microbiota; D010084:Oxidation-Reduction; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology
chemical_list: D012987:Soil; D000641:Ammonia