Anoxic N2 fluxes from freshwater sediments in the absence of oxidized nitrogen compounds

From anoxic incubated freshwater sediments, initially without inorganic nitrogen compounds in the overlying water, remarkable and unexpected N2 fluxes were estimated. N2 leakage from the atmosphere and oxygen leakage followed by nitrification and denitrification, two possible causes, were thoroughly examined but found to be incorrect. From these investigations it was furthermore concluded that the N2 fluxes are real. The fluxes appear only under anoxic conditions and at least one step in the forming has to be biological. How these N2 fluxes were formed remained unclear as alternative pathways for the anoxic forming of N2 found in literature did not give an explanation to the source and/or mechanism leading to the N2 fluxes either.