Population Ecology of Nitrifiers in a Stream Receiving Geothermal Inputs of Ammonium
AUTOR(ES)
Cooper, A. Bryce
RESUMO
The distribution, activity, and generic diversity of nitrifying bacteria in a stream receiving geothermal inputs of ammonium were studied. The high estimated rates of benthic nitrate flux (33 to 75 mg of N · m−2 · h−1) were a result of the activity of nitrifiers located in the sediment. Nitrifying potentials and ammonium oxidizer most probable numbers in the sediments were at least one order of magnitude higher than those in the waters. Nitrifiers in the oxygenated surface (0 to 2 cm) sediments were limited by suboptimal temperature, pH, and substrate level. Nitrifiers in deep (nonsurface) oxygenated sediments did not contribute significantly to the changes measured in the levels of inorganic nitrogen species in the overlying waters and presumably derived their ammonium supply from ammonification within the sediment. Ammonium-oxidizing isolates obtained by a most-probable number nonenrichment procedure were species of either Nitrosospira or Nitrosomonas, whereas all those obtained by an enrichment procedure (i.e., selective culture) were Nitrosomonas spp. The efficiency of the most-probable-number method for enumerating ammonium oxidizers was calculated to be between 0.05 and 2.0%, suggesting that measurements of nitrifying potentials provide a better estimate of nitrifying populations.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=242434Documentos Relacionados
- Feeding ecology of stream-dwelling fishes from a coastal stream in the Southeast of Brazil
- Feeding ecology of Rivulus luelingi (Aplocheiloidei: Rivulidae) in a Coastal Atlantic Rainforest stream, southern Brazil
- Ecology of Phallotorynus pankalos (Cyprinodontiformes: Poeciliidae) in a first-order stream of the upper Paraná Basin
- Concentrations of nitrifying bacteria in sewages, effluents, and a receiving stream and resistance of these organisms to chlorination.
- Feeding ecology of a stream fish assemblage in an Atlantic Forest remnant (Serra do Japi, SP, Brazil)