title: Correlations between in situ denitrification activity and nir-gene abundances in pristine and impacted prairie streams.
abstract: Denitrification is a process that reduces nitrogen levels in headwaters and other streams. We compared nirS and nirK abundances with the absolute rate of denitrification, the longitudinal coefficient of denitrification (i.e., Kden, which represents optimal denitrification rates at given environmental conditions), and water quality in seven prairie streams to determine if nir-gene abundances explain denitrification activity. Previous work showed that absolute rates of denitrification correlate with nitrate levels; however, no correlation has been found for denitrification efficiency, which we hypothesise might be related to gene abundances. Water-column nitrate and soluble-reactive phosphorus levels significantly correlated with absolute rates of denitrification, but nir-gene abundances did not. However, nirS and nirK abundances significantly correlated with Kden, as well as phosphorus, although no correlation was found between Kden and nitrate. These data confirm that absolute denitrification rates are controlled by nitrate load, but intrinsic denitrification efficiency is linked to nirS and nirK gene abundances.
authors: Department of Civil, Environmental and Architectural Engineering, University of Kansas, Lawrence, KS 66045, USA.
authors: David W
authors: DW
authors: Graham
authors: Clare
authors: C
authors: Trippett
authors: Walter K
authors: WK
authors: Dodds
authors: Jonathan M
authors: JM
authors: O'Brien
authors: Eric B K
authors: EB
authors: Banner
authors: Ian M
authors: IM
authors: Head
authors: Marilyn S
authors: MS
authors: Smith
authors: Richard K
authors: RK
authors: Yang
authors: Charles W
authors: CW
authors: Knapp
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D058440:Denitrification / Q000235:genetics*; D017753:Ecosystem; D009584:Nitrogen / Q000032:analysis*; D045483:Rivers / Q000737:chemistry* / Q000382:microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D001426:Bacterial Proteins; D014874:Water Pollutants, Chemical; D009584:Nitrogen