Field and laboratory studies of N_2O turnover in the saturated zone of hydromorphic soils of Northwest Germany. Ⅰ: N_2O surface emission and vertical distribution of concentrations and isotopomer signatures

摘要

Groundwater N_2O concentrations and emissions to the atmosphere are closely related to denitrifica-tion dynamics in the saturated zone. In the shallow groundwater of hydromorphic soils redox conditions are generally favorable for denitrification. The contribution of these environments to N_2O in the atmosphere depends on the partial processes of N_2O turnover in the saturated and unsaturated zones, i.e. production during nitrification and denitrification, consumption during denitrification, as well as convective and diffusive transport. The objectives of this study were to determine surface and subsurface fluxes of ground water derived N_2O and to evaluate the use of stable isotope natural abundance as a tool to trace ground water N_2O turnover.