南海中部海区次表层NO_2^--N的最大值

Subsurface nitrite maximum in central South China Sea

本文根据1983年9月至1985年1月南海中部海区综合调查所获得的NO_2^--N及有关参数的观测资料,分析了该海区NO_2^--N的分布变化特征及其与环境因子的关系。结果表明,调查海区NO_2^--N含量的变化范围在0～0.54μmol/L之间,其中小于0.05μmol/L的测定值约占测定总数的82.1%,而大于0.05μmol/L测定值基本上出现在50～150m层。文中还对该海区次表层NO_2^--N最大值形成的机理作了初步探讨,指出密度跃层的终年存在、铵的氧化和浮游植物的代谢过程是调查海区次表层NO_2^--N最大值形成的主要因素。

The distributional characteristics of nitrite and the relationship between subsurface nitrite maximum and environmental factors were studied based on the survey data of the central South China Sea from September 1983 to January 1985. It is shown the nitrite contents range from 0 to 0. 54μmol/L,of which the values lower than 0. 05μmol/L account for about 82. 1%and that higher than0. 05μmol/L are found in the subsurface layer(50～150m). The mechanism for the formation of nitrite maximum layers is discussed. It is concluded that existence of pycnocline in all seasons,oxidization of ammonium and metabolism of planktons in the subsurface layer are important factors for the formation of nitrite maximum layers in the area.