title: Nitrate turnover in a peat soil under drained and rewetted conditions: results from a [(15)N]nitrate-bromide double-tracer study.
abstract: Under natural conditions, peatlands are generally nitrate-limited. However, recent concerns about an additional N input into peatlands by atmospheric N deposition have highlighted the risk of an increased denitrification activity and hence the likelihood of a rise of emissions of the greenhouse gas nitrous oxide. Therefore, the aim of the present study was to investigate the turnover of added nitrate in a drained and a rewetted peatland using a [(15)N]nitrate-bromide double-tracer method. The double-tracer method allows a separation between physical effects (dilution, dispersion and dislocation) and microbial and chemical nitrate transformation by comparing with the conservative Br(-) tracer. In the drained peat site, low NO3(-) consumption rates have been observed. In contrast, NO3(-) consumption at the rewetted peat site rises rapidly to about 100% within 4 days after tracer application. Concomitantly, the (15)N abundances of nitrite and ammonium in soil water increased and lead to the conclusion that, besides commonly known NO3(-) reduction to nitrite (i.e. denitrification), a dissimilatory nitrate reduction to ammonium has simultaneously taken place. The present study reveals that increasing NO3(-) inputs into rewetted peatlands via atmospheric deposition results in a rapid NO3(-) consumption, which could lead to an increase in N2O emissions into the atmosphere.
authors: a Department of Soil Physics , Helmholtz Centre for Environmental Research - UFZ , Halle (Saale) , Germany.
authors: Rolf
authors: R
authors: Russow
authors: Nadine
authors: N
authors: Tauchnitz
authors: Oliver
authors: O
authors: Spott
authors: Sibylle
authors: S
authors: Mothes
authors: Sabine
authors: S
authors: Bernsdorf
authors: Ralph
authors: R
authors: Meissner
mesh_terms: D064751:Ammonium Compounds / Q000032:analysis; D001965:Bromides / Q000032:analysis; D004784:Environmental Monitoring; D005858:Germany; D009566:Nitrates / Q000032:analysis*; D009573:Nitrites / Q000032:analysis; D009587:Nitrogen Isotopes / Q000032:analysis; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D014867:Water / Q000737:chemistry; D053833:Wetlands
chemical_list: D064751:Ammonium Compounds; D001965:Bromides; D009566:Nitrates; D009573:Nitrites; D009587:Nitrogen Isotopes; D012987:Soil; D012989:Soil Pollutants; D014867:Water