冬季南海北部陆架锋区悬浮颗粒态硅的分析

A study on particulate silica in the northern part of the South China Sea in winter

对冬季南海北部陆架锋区的悬浮颗粒态生物硅(Particulate Biogenic Silica,PBSi)和成岩硅(Lithogenic Silica,LSi)含量进行了调查分析,讨论了悬浮颗粒态生物硅分布及其影响因素。结果表明,南海北部陆架区悬浮颗粒态生物硅和成岩硅平均含量分别为0.59和8.93μmol/dm3。生物硅分布与水团关系密切:在营养盐充足的沿岸水生物硅含量高(1.0μmol/dm3);而在营养盐缺乏的陆架表层水生物硅含量低(0.23μmol/dm3);在两种水团过渡区生物硅含量居中(0.65μmol/dm3)并与溶解硅酸盐(Dissolved Silicate,DSi)成显著正相关(R=0.48,N=44,P=0.001,a=0.01)。此外锋面位置也直接影响生物硅的含量与分布。大部分调查海区被高温高盐低营养盐海水占据,因此导致了调查海区以低浓度的生物硅和成岩硅为特征,且与世界其他海区相比,生物硅含量处于低值区。

The distribution of particulate biogenic silica （PBSi） and lithogenic silica （LSi） were studied in the northern part of South China Sea in winter 2004. The average concentrations of PBSi and LSi were 0.59 and 8.93 μmol/dm^3 , respectively. Due to the intrusion of offshore seawater, the concentrations of PBSi decreased greatly from the coastal water （1.0 μmol/dm^3） to the offshore water （0.23 μmol/dm^3）, just like the distribution of dissolved silicate （DSi）, which is related to the water mass and shelf front. The concentration of PBSi in the northern part of South China Sea is ranked at the lower end among the world coastal areas.