Yan Hui-Min, Liu Min, Hou Li-Jun, Xu Shi-Yuan, Lin Xiao
Key Laboratory of Geo-information Science of the Ministry of Education, Department of Geography, East China Normal University, Shanghai 200062, China.
Huan Jing Ke Xue. 2008 Jan;29(1):164-9.
Distributions of biogenic silica (BSi) in surface sediments from the shoals in the Yangtze Estuary were investigated using an 8-hour sequential extraction method, and the relationships of BSi with the sediment physio-chemical characteristics were also discussed. The findings indicated that the BSi contents in the shoal sediments varied from 0.47% to 1.02%, and the average content was 0.75%. The BSi contents range of the high, middle and low intertidal flats was 0.47%-0.91%, 0.48%-1.02% and 0.47%-0.96%, respectively. The significant positive relationships were found between BSi and the clay and silt contents in sediments, which indicated that the accumulation of BSi in sediments closely depended on sediment compositions. There also existed the remarkable positive relationships between BSi and organic carbon (OC) and nitrogen (ON). This implied that BSi was apt to accumulate in sediments enriched in organic matter. Compared with Redfield ratios, the ratios of OC/BSi and ON/BSi in shoal sediments were relatively lower and in the range of 0.28-2.59 and 0.05-0.21, respectively. Therefore, it was shown that the dissolution rate of BSi in shoal sediments was lower than the rate of organic matter decomposition. In addition, it was also found that there was the weak positive correlation between BSi and chlorophyll in the sediments, reflecting that primary productivity such as diatoms, to some certain, made contribution to the storage of BSi.
采用8小时连续提取法研究了长江河口浅滩表层沉积物中生物源二氧化硅(BSi)的分布情况,并探讨了BSi与沉积物理化特性之间的关系。研究结果表明,浅滩沉积物中BSi含量在0.47%至1.02%之间,平均含量为0.75%。高潮滩、中潮滩和低潮滩的BSi含量范围分别为0.47% - 0.91%、0.48% - 1.02%和0.47% - 0.96%。发现BSi与沉积物中的黏土和粉砂含量之间存在显著正相关关系,这表明沉积物中BSi的积累密切依赖于沉积物组成。BSi与有机碳(OC)和氮(ON)之间也存在显著正相关关系。这意味着BSi易于在富含有机质的沉积物中积累。与雷德菲尔德比值相比,浅滩沉积物中OC/BSi和ON/BSi的比值相对较低,分别在0.28 - 2.59和0.05 - 0.21范围内。因此,表明浅滩沉积物中BSi的溶解速率低于有机质分解速率。此外,还发现沉积物中BSi与叶绿素之间存在弱正相关关系,反映出硅藻等初级生产力在一定程度上对BSi的储存有贡献。