title: Ancient landscapes and the relationship with microbial nitrification.
abstract: Ammonia oxidizing archaea (AOA) and bacteria (AOB) drive nitrification and their population dynamics impact directly on the global nitrogen cycle. AOA predominate in the majority of soils but an increasing number of studies have found that nitrification is largely attributed to AOB. The reasons for this remain poorly understood. Here, amoA gene abundance was used to study the distribution of AOA and AOB in agricultural soils on different parent materials and in contrasting geologic landscapes across Australia (n = 135 sites). AOA and AOB abundances separated according to the geologic age of the parent rock with AOB higher in the more weathered, semi-arid soils of Western Australia. AOA dominated the younger, higher pH soils of Eastern Australia, independent of any effect of land management and fertilization. This differentiation reflects the age of the underlying parent material and has implications for our understanding of global patterns of nitrification and soil microbial diversity. Western Australian soils are derived from weathered archaean laterite and are acidic and copper deficient. Copper is a co-factor in the oxidation of ammonia by AOA but not AOB. Thus, copper deficiency could explain the unexpectedly low populations of AOA in Western Australian soils.
authors.affiliation: Soil Biology and Molecular Ecology Group, School of Earth and Environment and the Institute of Agriculture, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
authors.forename: Sasha N
authors.initials: SN
authors.lastname: Jenkins
authors.affiliation: Soil Biology and Molecular Ecology Group, School of Earth and Environment and the Institute of Agriculture, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Murphy
authors.affiliation: Soil Biology and Molecular Ecology Group, School of Earth and Environment and the Institute of Agriculture, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
authors.forename: Ian S
authors.initials: IS
authors.lastname: Waite
authors.affiliation: School of Biology, Newcastle University, Newcastle upon Tyne, NE1 7RU, England, UK.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Rushton
authors.affiliation: Soil Biology and Molecular Ecology Group, School of Earth and Environment and the Institute of Agriculture, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: O'Donnell
mesh_terms: D000383:Agriculture; D001105:Archaea / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D019843:Archaeal Proteins / Q000235:genetics; D001315:Australia; D001419:Bacteria / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D001426:Bacterial Proteins / Q000235:genetics; D003300:Copper / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D058465:Nitrification; D010088:Oxidoreductases / Q000235:genetics*; D012988:Soil Microbiology
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D003300:Copper; D010088:Oxidoreductases; C045582:ammonia monooxygenase