Silica Dissolution In Sediments Of The Southern Ocean: An Integrated Field, Laboratory And Modeling Study

9312220 VANCAPPELIN从海洋中去除硅的主要机制是在沉积物中埋藏生物成因二氧化硅残留物。生物源二氧化硅的埋藏通量受地表水中的生成量、水柱和表层沉积物中的溶解作用的控制。为了更好地了解生物成因二氧化硅的溶解过程，将使用新收集的沉积物材料和天然海水进行流动实验。实验将研究pH、温度、钠、镁和铝对溶解过程的影响。拟议的研究还将确定生物成因二氧化硅的反应性随沉积物中深度/时间的变化。这项研究将包括表面绒毛层材料的溶解实验，以量化在水-沉积物界面回收的沉积生物源二氧化硅的数量。实验确定的动力学速率定律、速率常数和溶解度将包含在二氧化硅的早期成岩模型中。该模型将被用来测试(1)从沉积物到上覆水的硅酸通量和(2)颗粒二氧化硅的埋藏通量对二氧化硅沉积通量变化的响应。

9312220 VANCAPPELLIN The major mechanism removing silicon from the oceans is the burial in sediments of biogenic silica remains. The burial flux of biogenic silica is controlled by production in surface waters, and by dissolution in the water column and surface sediments. To gain a better understanding of the dissolution process of biogenic silica, flow-through experiments will be performed with freshly collected sediment material and natural seawater. The experiments will address the role of pH, temperature, Na, Mg and Al on the dissolution process. The proposed research will also establish the evolution of the reactivity of biogenic silica as a function of depth/time in the sediments. The study will include dissolution experiments with the superficial fluff layer material, in order to quantify the amount of deposited biogenic silica that is recycled at the water-sediment interface. The experimentally determined kinetic rate laws, rate constants and solubilities will be included in an early diagenetic model for silica. The model will be used to test the response of (1) the flux of silicic acid from the sediments to the overlying water and (2) the burial flux of particulate silica, to variations of the silica deposition flux.