ADVANCES IN POLAR SCIENCE ›› 2012, Vol. 23 ›› Issue (2-English): 87-94.DOI: 10.3724/SP.J.1085.2012.00087

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Multiple processes affecting surface seawater N2O saturation anomalies in tropical oceans and Prydz Bay, Antarctica

CHEN Liqi1,2, ZHAN Liyang1,2, XU Suqing1,2, ZHANG Jiexia1,2, ZHANG Yuanhui1,2 &
XU Guojie1,2   

  1. 1 Key Laboratory of Global Change and Marine-Atmospheric Chemistry, State Oceanic Administration (SOA) ;
    2 Third Institute of Oceanography, SOA
  • Received:2012-03-16 Revised:2012-03-25 Online:1962-06-30 Published:1962-06-30
  • Contact: CHEN Liqi
  • Supported by:

    the National Natural Science Foundations of China;State High Technique Research Development Project;Ministry of Science and Technology of China;CAA cooperation program

Abstract: We analyzed the N2O content in surface seawater sampled in Prydz Bay, Antarctica, on a cruise track between 30°S and 30°N during the 22nd Chinese Antarctic Research Expedition during austral summer, 2006. The surface water showed an average pN2O value of 311.9±7.6 nL/L (14.1±0.4 nmol/L), being slightly undersaturated; the air-sea N2O flux of this region was -0.3±0.8 μmol/(m2?d). However, N2O in the surface water was oversaturated in most stations along the cruise track. Saturation anomalies were above 10%, in maximum of 54.7% found at the Equator, followed by 31% at 10°N in the Sulu Sea; in other words, the air-sea fluxes at these locations were 12.4 and 4 μmol/(m2?d), respectively. Therefore, we believe that the surface water in Prydz Bay was near equilibrium with atmospheric N2O, and ocean waters in lower latitudes acted as a N2O source. Physical processes, such as stratification, ice-melt water dilution, and solar radiation dominate the N2O saturation in surface water Prydz Bay; While biological production and upwelling in subtropical and tropical regions should responsible for N2O over saturation in Surface water along the cruise track.

Key words: dissolved N2O, saturation anomalies, tropic, subtropic, Prydz Bay