The global budget of nitrous oxide is dominated by terrestrial and marine biological sources and atmospheric sinks. Details of the
budget remain unclear, including the cause of increasing atmospheric N_2O concentrations. Marine sources of N_2O include
denitrification and nitrification. Our understanding of the major microbial players in the nitrogen cycle has changed in recent years
(for example, the nitrifying Archaea), and the overall contributions of these organisms to N_2O production and their isotopic signatures
are poorly constrained [1]