Peer-Reviewed Journal Details
Mandatory Fields
Barrett, M,Jahangir, M,Lee, C,Smith, C,Bhreathnach, N,Collins, G,Richards, K,O'Flaherty, V
2013
September
Environmental Science And Pollution Research
Abundance of denitrification genes under different peizometer depths in four Irish agricultural groundwater sites
Published
WOS: 12 ()
Optional Fields
Denitrification Subsoil Piezometer Groundwater nirK nirS nosZ qPCR DENITRIFYING BACTERIA NITRATE CONCENTRATION NOSZ GENES SOILS WATER NIRK MANAGEMENT REDUCTASE AQUIFER DIVERSITY
20
6646
6657
This study examined the relationship between the abundance of bacterial denitrifiers in groundwater at four sites, differing with respect to overlaying land management and peizometer depth. Groundwater was sourced from 36 multilevel piezometers, which were installed to target different groundwater zones: (1) subsoil, (2) subsoil to bedrock interface, and (3) bedrock. The gene copy concentrations (GCCs), as gene copies per liter, for bacterial 16S rRNA genes and the denitrifying functional genes, nirK, nirS, and nosZ, were determined using quantitative polymerase chain reaction assays. The results were related to gaseous nitrogen emissions and to the physicochemical properties of the four sites. Overall, nirK and nirS abundance appeared to show no significant correlation to N2O production (P = 0.9989; P = 0.3188); and no significant correlation was observed between nosZ and excess N-2 concentrations (P = 0.0793). In the majority of piezometers investigated, the variation of nirK and nirS gene copy concentrations was considered significant (P < 0.0001). Dissolved organic carbon (DOC) decreased with aquifer depth and ranged from 1.0-4.0 mg l(-1), 0.9-2.4 mg l(-1), and 0.8-2.4 mg l(-1) within piezometers located in the subsoil, subsoil/bedrock interface, and bedrock depths, respectively. The availability of increasing DOC and the depth of the water table were positively correlated with increasing nir and nosZ GCCs (P = 0.0012). A significant temporal correlation was noted between nirS and piezometer depth (P < 0.001). Interestingly, the nirK, nirS, and nosZ GCCs varied between piezometer depths within specific sites, while GCCs remained relatively constant from site to site, thus indicating no direct impact of agricultural land management strategies investigated on denitrifier abundance.
10.1007/s11356-013-1729-3
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