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Coexistence of nitrous oxide undersaturation and oversaturation in the surface and subsurface of the western Arctic Ocean
Author(s) -
Zhang Jiexia,
Zhan Liyang,
Chen Liqi,
Li Yuhong,
Chen Jianfang
Publication year - 2015
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2015jc011245
Subject(s) - halocline , oceanography , surface water , arctic , nitrification , meltwater , nitrous oxide , geology , water column , bottom water , environmental science , nitrogen , geomorphology , chemistry , snow , salinity , organic chemistry , environmental engineering
The nitrous oxide (N 2 O) distributions in a shelf‐slope‐basin section from the Chukchi Sea shelf to the Chukchi Abyssal Plain (CAP) in the western Arctic Ocean were observed for the first time during the fourth Chinese National Arctic Research Expedition (4th CHINARE) in late August 2010. The N 2 O concentrations were 11.4–16.9 nmol L −1 , corresponding to saturation values of 92–118% in the surface water. In the surface, biological factor was negligible to N 2 O production, and physical process dominated the surface N 2 O distribution. The N 2 O undersaturation may be the result of dilution by sea ice meltwater. The oversaturation may be caused by the diffusing of N 2 O‐rich shelf bottom water. Below the surface, N 2 O concentrations ranged from 11.4 to 21.4 nmol L −1 . On the Chukchi Sea shelf, N 2 O concentrations increased from the surface to the near‐bottom water, indicating sediment N 2 O produced by nitrification or denitrification emission may be a significant source. The subsurface maxima in the upper halocline layer (UHL) may receive partial contribution from nitrification production but was primarily caused by the spreading of shelf water.