Seasonal and spatial variability in N₂O distribution in the Arabian Sea

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• 作者：Patra ; Prabir K. ; Lal ; Shyam ; Venkataramani ; S. ; de Sousa ; S.N. ; Sarma ; V.V.S.S. ; Sardesai ; S.
• 刊名：Deep Sea Research Part I: Oceanographic Research Papers
• 出版年：1999
• 出版时间：March, 1999
• 年：1999
• 卷：46
• 期：3
• 页码：529-543
• 全文大小：360 K

文摘

Extensive measurements of nitrous oxide (N₂O) were made in the central and eastern Arabian Sea during the northeast monsoon (February–March), intermonsoon (April–May) and southwest monsoon (July–August) seasons. The latitudinal and longitudinal variations, along with seasonal changes with respect to winter convection and coastal upwelling, are clearly discernible. Vertical profiles collected down to 1000 m show that the Arabian Sea water column is supersaturated with N₂O at all depths. However, N₂O consumption at intermediate depths, coincident with the oxygen minimum and associated with sediment–water interfaces, and in the denitrifying zone, coincident with NO^-₂ secondary maxima, are also apparent. The N₂O concentration varies from 10 nM near the surface to about 80 nM in the secondary peak region (≈800 m). Interrelationships with chemical parameters suggest nitrification to be the main process for the production of N₂O in the oceanic water. Plots of apparent oxygen utilization vs production of N₂O indicate a consistent linear relationship for AOU between 0 and 200 μM.