Microbial Oxidation of Pyrite Coupled to Nitrate Reduction in Anoxic Groundwater Sediment
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Microbial Oxidation of Pyrite Coupled to Nitrate Reduction in Anoxic Groundwater Sediment. / Jørgensen, Christian Juncher; Elberling, Bo; Jacobsen, Ole Stig; Aamand, Jens.
In: Environmental Science and Technology, Vol. 43, No. 13, 2009, p. 4851-4857.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Microbial Oxidation of Pyrite Coupled to Nitrate Reduction in Anoxic Groundwater Sediment
AU - Jørgensen, Christian Juncher
AU - Elberling, Bo
AU - Jacobsen, Ole Stig
AU - Aamand, Jens
PY - 2009
Y1 - 2009
N2 - Although many areas in Denmark are intensively agricultured, the discharge of nitrate from groundwater aquifers to surface water is often lower than expected. In this study it is experimentally demonstrated that anoxic nitrate reduction in sandy sediment containing pyrite is a microbially mediated denitrification process with pyrite as the primary electron donor. The process demonstrates a temperature dependency (Q10) of 1.8 and could be completely inhibited by addition of a bactericide (NaN3). Experimentally determined denitrification rates show that more than 50% of the observed nitrate reduction can be ascribed to pyrite oxidation. The apparent zero-order denitrification rate in anoxic pyrite containing sediment at groundwater temperature has been determined to be 2-3 µmol NO3- kg-1 day-1. The in situ groundwater chemistry at the boundary between the redoxcline and the anoxic zone reveals that between 65 and 80% of nitrate reduction in the lower part of the redoxcline is due to anoxic oxidation of pyrite by nitrate with resulting release of sulfate. It is concluded that microbes can control groundwater nitrate concentrations by denitrification using primarily pyrite as electron donor at the oxic-anoxic boundary in sandy aquifers thus determining the position and downward progression of the redox boundary between nitrate-containing and nitrate-free groundwater.
AB - Although many areas in Denmark are intensively agricultured, the discharge of nitrate from groundwater aquifers to surface water is often lower than expected. In this study it is experimentally demonstrated that anoxic nitrate reduction in sandy sediment containing pyrite is a microbially mediated denitrification process with pyrite as the primary electron donor. The process demonstrates a temperature dependency (Q10) of 1.8 and could be completely inhibited by addition of a bactericide (NaN3). Experimentally determined denitrification rates show that more than 50% of the observed nitrate reduction can be ascribed to pyrite oxidation. The apparent zero-order denitrification rate in anoxic pyrite containing sediment at groundwater temperature has been determined to be 2-3 µmol NO3- kg-1 day-1. The in situ groundwater chemistry at the boundary between the redoxcline and the anoxic zone reveals that between 65 and 80% of nitrate reduction in the lower part of the redoxcline is due to anoxic oxidation of pyrite by nitrate with resulting release of sulfate. It is concluded that microbes can control groundwater nitrate concentrations by denitrification using primarily pyrite as electron donor at the oxic-anoxic boundary in sandy aquifers thus determining the position and downward progression of the redox boundary between nitrate-containing and nitrate-free groundwater.
U2 - 10.1021/es803417s
DO - 10.1021/es803417s
M3 - Journal article
VL - 43
SP - 4851
EP - 4857
JO - Environmental Science & Technology. News & Research Notes
JF - Environmental Science & Technology. News & Research Notes
SN - 1086-931X
IS - 13
ER -
ID: 14858550