The balance between biogenic silica production and its dissolution in the surface ocean

生物二氧化硅的产生与其在表层海洋中的溶解之间的平衡

基本信息

批准号：
17310005
负责人：
TAKEDA Shigenobu
金额：
$ 10.46万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17310005/
关键词：
Earth science Marine ecosystem Silicon Diatoms Stable isotope Mass spectrometry Biogenic silica Phytoplankton ケイ藻地球化学ケイ酸

项目摘要

Production and dissolution rates of biogenic silica (diatom frustules) in the surface waters were determined simultaneously using silicon stable isotope tracer to investigate balance between biogenic silica production and its dissolution in the surface waters of the western subarctic North Pacific Ocean. New analytical method for the determination of silicon isotope ratios was developed using a high-resolution Inductively Coupled Plasma-Mass Spectrometry. By correcting background Si peaks, analytical precision and sensitivity similar to those of the thermal ionization mass spectrometry were obtained. This method was used for the determination of the rates of biogenic silica production and dissolution in the Oyashio surface water of the western subarctic North Pacific. Column integrated dissolution rate of biogenic silica exceeded production rate by diatoms within the euphotic layer, suggesting active silicic acid dissolved from particulate biogenic silica and its utilization by diatoms in the surface mixed layer. Batch dissolution experiments of diatom frustules obtained from the western subarctic North Pacific were also conducted in the laboratory to investigate differences in dissolution kinetics between the dominant diatom groups. Observed dissolution rates indicated that degree of solubility of diatom frustules is different between the diatom species as well as the site of the frustules. Morphological changes of diatom frustules during the dissolution process seem to be an important factor affecting surface/volume ratio of the frustules and consequently its dissolution rate. From these results, most of the biogenic silica produced by diatoms was estimated to be recycling in the surface ocean. However, existence of diatom frustules in the deep layers implies that rapid sinking of diatom containing feral pellets should be considered as another important process in the marine silicon cycles.

使用硅稳定的同位素示踪剂同时确定地表水中生物二氧化硅（硅化液膜）的生产和溶解速率，以研究生物二氧化硅产生与其在西部亚北太平洋西部地表水中的溶解之间的平衡。使用高分辨率的电感耦合等离子体 - 质谱法开发了用于测定硅同位素比率的新分析方法。通过校正背景SI峰，获得了与热电离质谱法相似的分析精度和灵敏度。该方法用于确定北太平洋西部北太平洋的Oyashio地表水中的生物二氧化硅产生和溶解的速率。柱综合生物二氧化硅的溶解速率超过了爵士层内的硅藻的产量，这表明活性硅酸溶于颗粒生物二氧化硅及其在表面混合层中的硅藻的利用。还在实验室中进行了从西部亚亚北太平洋获得的硅藻瓣的分批溶解实验，以研究显性硅藻基团之间溶解动力学的差异。观察到的溶解速率表明，硅藻种类的硅藻液的溶解度在硅藻物种和冰丝部位之间有所不同。在溶解过程中，硅藻瓣的形态变化似乎是影响冰块表面/体积比及其溶解速率的重要因素。从这些结果中，估计由硅藻产生的大多数生物二氧化硅在地面海洋中回收。然而，深层中存在硅藻的存在意味着，含有野性颗粒的硅藻的快速下沉应被视为海洋硅周期中的另一个重要过程。