Nitrous oxide (N2O) in the north-eastern Arabian Sea and its formation pathways, a stable isotope and isotopomeric perspective

Nitrous oxide (N2O) is a biogenic trace gas in the atmosphere having significant role in global climate change and stratospheric chemistry. Its concentration in the ambient air has increased to the current value of 325 ppbv from 275ppbv in last hundred years. Oceans account for 25-30 % of global N2O emissions. Tropical and coastal regions contributes to more than 50 % of oceanic emissions; however, the biogeochemical pathways leading to its formations are poorly constrained. Nitrification and denitrification dominates N2O production with their N2O source product varying with oxygen availability. This paper describes the dissolved nitrous oxide concentration and its changes with apparent oxygen utilisation (AOU) along the Northeast Arabian Sea waters during South West Monsoon. Stable isotopic study of N2O including d15Nbulk, d18O, d15Nα and its site preference (SP) which is the difference between d15N α and d15N β were also conducted for the first time in this oceanic regions. The N2O were highly concentra...