南大洋普里兹湾沉积物中生物硅的溶解度研究

摘要

利用中国南极科学考察航次(第18、21、24次)获得的沉积物样品,采用分批(batch)实验方法,获取实验室生物硅溶解度,并结合间隙水中可溶性硅剖面,对普里兹湾沉积物中生物硅的溶出过程进行了初步研究.研究结果如下:在25℃,pH 8条件下,普里兹湾IV-10、IS-4站表层沉积物中生物硅的实验室溶解度分别为1 936、1 540 μmol·dm-3,不同层次沉积物溶出结果显示随深度增加溶解度值降低.根据实验室溶解度数据与间隙水硅酸盐Cd的分析比较,表明研究站位沉积物生物硅的早期成岩过程中生物硅的溶出还伴随有其他化学过程.%Laboratory-based solubility determinations of biogenic silica were performed in batch reactors on sediments from two cores collected in Prydz Bay,in the Southern Ocean.The results show that the apparent solubility of biogenic silica (BSi) in the top sediments of stations IV-10 and IS-4 were 1 930 μmol · dm-3 and 1 540 μmol o dm" ,respectively,and the solubility decreased with depth in the core.The apparent solubility of BSiwas much higher than the value of an asymptotic concentration (Cd) of dissolved silica(DSi) in pore water.The pore water distributions of DSi record early diagenetic histories that may involve chemical interactions other than the simple dissolution of the deposited BSi.