Production and emissions of oceanic nitrous oxide

• Main Author: Freing, Alina
• Format: Thesis
• Language: English
• Published: 2009
• Subjects: North Atlantic
• Online Access: https://oceanrep.geomar.de/id/eprint/3344/; https://oceanrep.geomar.de/id/eprint/3344/1/freing_dissertation.pdf; https://macau.uni-kiel.de/receive/diss_mods_00004273

This study calculates N2O production rates (N2OPR) based on concentration measurements and Transit Time Distribution (TTD) calculations. New parameterisations of N2OPR based on an apparent oxygen consumption rate (AOUR and temperature or depth, respectively, are developed and applied to calculate N2O production the entire ocean. A global annual subsurface N2O production of ~3±1 Tg N and a global annual organic carbon remineralisation rate of 17.6 Pg are estimated. The N2O flux to the mixed layer (F_grad) and the N2O emissions to the atmosphere via gas exchange (F_gasex) are calculated or the central North Atlantic. The mean F_grad is found to be significantly smaller than the mean F_gasex. A possible reason for this is the seasonality of surface pN2O/F_gasex, as a seasonally-resolved, integrated estimate of F_gasex significantly reduces the difference between the two flux estimates. There is no conclusive evidence for a biological N2O source in the mixed layer.