东海海水中的溶存甲烷

基于1994年秋季航次在东海的调查资料,较详细地分析了溶存甲烷在水体中的分布规律、成因和来源.表层水中溶存甲烷呈过饱和状态,饱和度127%～254%,温跃层以上水体中,甲烷的断面分布不同于营养盐的分布,各站测值相近,没有显示出受长江冲淡水的影响,而呈现的舌状分布,在陆架底层水中有明显的高浓度甲烷水体,表明甲烷从沉积物中迅速扩散进入底层水.黑潮次表层水的涌升过程稀释了陆架边缘底层水中的甲烷.在陆架和大洋区测站上,甲烷的垂直分布不同,前者主要受物理混合过程所控制;后者呈大洋区分布特征,在温跃层附近出现甲烷的次表层最大,这可能是陆架底层高浓度甲烷沿等密度面的输送所致.

Dissolved methane in sea water of the East China Sea

Based on our investigated data for the East China Sea in autumn 1991,the paper discusses the dissolved methane distribution features,formation mechanism, and sources of methane in sea water in detail.In the surface water, the dissolved methane is supersaturation and the saturation is 127%-259%.Above the thermocline,the sectional distribution of methane is different from the nutrient's.The values of each station are almost similar to each other.It is not shown that the tongue shaped distribution under the influence of the Changjiang diluted water.There is the higher concentrations in the bottom water and it is shown that the methane diffuses rapidly into the water from the sediments on the continental shelf.The upwelled process of the Kuroshio subsurface water dilutes the methane concentration in the bottom water on the shelf.The methane vertical profiles show various distributions on the shelf and open ocean.The former is mainly controlled by the physical mixing process.The later shows the open oceanic feature.There is the subsurface methane maximum around the thermocline.It is possible that the bottom water with higher methane on the shelf is transported along the isopycnal surface.