• DOI:10.2134/JEQ1999.00472425002800010032X
• Corpus ID: 40226710

In Situ Measurements of Denitrification in Constructed Wetlands

@article{Xue1999InSM,
  title={In Situ Measurements of Denitrification in Constructed Wetlands},
  author={Yuan Xue and David A. Kovacic and Mark B. David and Lowell E. Gentry and Richard Lesley Mulvaney and Charles W. Lindau},
  journal={Journal of Environmental Quality},
  year={1999},
  volume={28},
  pages={263-269}
}

• Yuan Xue, D. Kovacic, +3 authors C. Lindau
• Published 1999
• Engineering, Environmental Science
• Journal of Environmental Quality

Quantitative estimates of denitrification are needed in designing artificial wetlands to optimize nitrate (NO 3 - ) removal. Acetylene blockage and 15 N-tracer methods were employed to quantify denitrification in constructed wetlands receiving agricultural tile drainage, using plastic tubes to enclose in situ mesocosms. Estimates were also made through NO 3 - disappearance from mesocosm water columns. The 15 N and C 2 H 2 methods yielded comparable rates. At 4 to 25°C, and with 9 to 20 mg NO 3 -N L -1 initially in the mesocosm water columns, denitrification rates by the C 2 H 2 technique ranged from 2.0 to 11.8 mg N m -2 h -1 . In the June-August 15 N experiment, when wetland NO 3 was below detection, a time series of denitrification rates followed a bell-shaped curve after a pulse input of NO 3 - (∼15 mg N L -1 , 70 atom% 15 N). The maximal denitrification rate (9.3 mg N m -2 h -1 ) was observed 5.4 d after the pulse. After 33 d, 58% of the 15NO3 - had been evolved as N 2 , only ∼0.1% as N 2 O; 6 to 10% was recovered in plant shoots and as organic N in the upper 5 cm of sediment. From 32 to 36% of the 15 NO 3 - spike was not recovered, and presumably seeped into the sediments. The NO disappearance rates in the water column ranged from 12 to 63 mg N m -2 h -1 at 11 to 27°C. Because water infiltration carries NO 3 through the anaerobic sediment/water interface for denitrification, a subsurface-flow wetland may denitrify more NO 3 - than a surface-flow wetland.