北极楚科奇海沉积生物硅的分布及其硅质泵过程初探

Biogenic Silica Distribution in Chukchi Sea and Its Implications for Silicate Pump Process

依托第3次、第4次、第5次北极科学考察在北极楚科奇海采集的表层沉积物样品,通过碱液连续提取法对生物硅含量进行分析,以探讨楚科奇海的生物硅分布及硅质泵过程。结果显示,楚科奇海表层沉积物中生物硅的含量为1.23%~10.60%。高值区位于楚科奇海陆坡处72°N附近和楚科奇海南部阿纳德尔流和西伯利亚沿岸流的交界处68°N附近,低值区位于楚科奇海东部阿拉斯加沿岸流影响区域,其生物硅含量小于3%。楚科奇海表层沉积物中生物硅的分布与上层水体的初级生产力的分布格局较一致,而影响上层水体浮游植物生产的两个重要因素分别为楚科奇海环流格局（尤其是太平洋入流水的影响）和海冰融化。生物硅和有机碳之间存在很好的正相关关系,表层沉积物中蛋白石/有机碳（Sibio/Corg）的比值为1.6~2.02,与北太平洋中该比例相当,表明上层海洋硅质泵过程对楚科奇海碳埋藏的贡献较大,使得楚科奇海成为全球海洋吸收大气CO2重要的汇之一。

Biogenic silica content in marine surface sediments collected from three Chinese Arctic Research Expeditions in Chukchi Sea was determined with continuous alkaline extraction methods. The results showed that the content of biogenic silica in surface sediments was 1. 23% ~ 10. 60%. Two high-content areas are located in the slope of the Chukchi Sea（ 72°N） and the northern part of the Bering Strait in southern Chukchi Sea where Anadyr Water and Eastern Siberian Coastal Water meets（ 68°N）; Low content area is located in east Chukchi Sea influenced by Alaska Coastal Water,with biogenic silica content 3%or less. The main factors controlling the biogenic silica distribution patterns include the upper primary productivity,circulation patterns in Chukchi Sea（ especially the Pacific water inflow into Chukchi Sea） and influence of sea ice. The existence of a good positive correlation between biogenic silica and organic carbon indicated the contribution of silicate pump in biological pump.Opal / organic carbon ratio（ Sibio/ Corg） in Chukchi Sea was varied from 1.6 to 2.02,the same magnitude as it was in North Pacific Ocean,indicating the high biological pump efficiency in Chukchi,especially for the large contribution of silicate pump,making the Chukchi Sea become one of the important global atmospheric CO2 sinks area.