Diversity of the nitrite reductase gene nirS in the sediment of a free-water surface constructed wetland

Autores/as

  • Olaya Ruiz-Rueda Institute of Aquatic Ecology, Faculty of Sciences, University of Girona, Girona, Spain
  • Rosalia Trias Institute of Aquatic Ecology, Faculty of Sciences, University of Girona, Girona, Spain
  • Librado J. Garcia-Gil Department of Biology, University of Girona, Girona, Spain
  • Lluís Bañeras Institute of Aquatic Ecology, Faculty of Sciences, University of Girona, Girona, Spain

Palabras clave:

nirS gene, denitrification, free water surface constructed wetland, sediments

Resumen

The diversity of the nitrite reductase gene nirS was studied in the bulk sediment of a free-water surface constructed wetland (FWS-CW) located next to the Empuriabrava wastewater treatment plant (WWTP), in Castelló d’Empúries (Girona, NE Spain). The study period extended from the inception of the treatment wetland, in June 1998, until March 1999 and comprised periods of relatively high nitrate and ammonium concentrations at the influent and low nitrate-removal efficiencies. To evaluate nirS diversity, partial gene sequences were obtained by cloning of the respective PCR products. Rarefaction curves based on DOTUR analyses of the deduced amino-acid sequences predicted a greater diversity of nirS genes in samples containing higher ammonium concentrations. Estimated Shannon-Weaver indices of the four cloned samples showed a positive relationship with the N-NH4 +/N-NO3− ratios measured at the FWS-CW inlet. Identities between the deduced amino-acid sequences and those previously deposited in public databases ranged from 72 to 97%. Phylogenetic analysis based on these deduced sequences grouped 165 nirS clones in seven main clusters according to high similarity indices. Up to 60% of the clones clustered together in a highly homogeneous group with little homologies to any sequence retrieved from cultured representatives. Moreover, prevailing environmental conditions appeared to select for particular denitrifying populations, e.g., with respect to ammonium load and nitrogen removal efficiencies. This observation is of particular interest for the management of treatment wetlands, in which only slight variations in the theoretical denitrification potential of the system can occur. [Int Microbiol 2007; 10(4): 253-260]

Biografía del autor/a

Olaya Ruiz-Rueda, Institute of Aquatic Ecology, Faculty of Sciences, University of Girona, Girona, Spain

Institute of Aquatic Ecology, Faculty of Sciences, University of Girona, Girona, Spain

Rosalia Trias, Institute of Aquatic Ecology, Faculty of Sciences, University of Girona, Girona, Spain

Institute of Aquatic Ecology, Faculty of Sciences, University of Girona, Girona, Spain

Librado J. Garcia-Gil, Department of Biology, University of Girona, Girona, Spain

Department of Biology, University of Girona, Girona, Spain

Lluís Bañeras, Institute of Aquatic Ecology, Faculty of Sciences, University of Girona, Girona, Spain

Institute of Aquatic Ecology, Faculty of Sciences, University of Girona, Girona, Spain

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Publicado

2010-01-21

Número

Sección

Research Articles