Nitrogen-15: Microbiological Alteration of Abundance

Abstract
The abundance of N15 relative to N14 is significantly altered during experiments in vitro in which nitrate and nitrite are microbiologically reduced to nitrogen gas. In all studies to date, N14O3-and N14O2-species have been preferentially reduced. This selectivity has a complex dependence on conditions in the medium. The results are not only relevant to natural variations in N15 relative to N14 but should be seriously considered during N15 tracer studies in soils.