Cultivation of diatoms using Tb-doped silicate minerals to characterize silicon utilized by diatoms

硅藻占海洋初级产品的70%，是生物泵的重要组成部分。这是因为它们通过将被吸收的碳输送到相对稳定的二氧化硅胶囊中，有效地隔离了大气中的二氧化碳。然而，对硅藻华的时间没有给出明确的解释。我们进行了硅藻的培养实验，研究硅藻结合硅的化学形态。到目前为止，我们取得了以下成绩：1)培养与分析石英颗粒是硅的唯一来源时，观察到增殖现象，掺铽体系中也观察到类似的增殖现象。用两个过滤器成功地分离了硅颗粒、硅藻和海水，用氢氧化钠溶液煮沸分离样品也成功地测定了石英颗粒和硅藻中的硅。2)培养装置：设计了波浪发生器，并将其置于可控培养箱中，模拟硅藻生长的自然环境。3)抑制分析中硅的空白值参考培养应在硅浓度相对较低的水平上进行，这可以通过选择和洗涤适当的设备和塑料器皿来实现。4)硅藻培养的时间和条件摇摇抑制硅藻的增殖，2周至1个月间观察硅藻的增殖情况。硅藻中铽的掺入硅藻中含有可检测到的铽，表明硅藻利用了石英颗粒中的硅。然而，人们发现需要一些重复实验来证实结果。

Diatoms are responsible for as much as 70% of the primary product in the ocean and play a major role of biological pump. This is because they sequester the atmospheric carbon dioxide effectively by transporting assimilated carbon into deeper layer of the ocean in capsules of relatively stable silica. However, the clear explanation for the timing of diatom bloom has not been given. We have conducted cultivation experiments of diatoms to investigate the chemical form of silicon incorporated by diatoms. So far, we have made the following achievements itemized below.1) Cultivation and analysisProliferation was observed when quartz particles were exclusive source of silicon and Similar proliferation was observed in the terbium doped system. The silicon particles, diatoms and seawater were successfully separated with two filters and the determination of silicon in quartz particles and diatoms was also successful with boiling the separated samples in a sodium hydroxide solution.2) Cultivation apparatusA wave-generator was designed and set in a controlled cultivation box to mimic the natural environment of diatom growth.3) The suppression of blank value of silicon in the analysisReference cultivations should be conducted at the comparatively small level of silicon concentration, which was made possible by selecting and washing proper equipments and plastic-ware.4) Time and condition of the diatom cultivationProliferation of diatoms was suppressed with rocking and the proliferation of diatoms were observed between two weeks and one month times.5) Incorporation of terbium in diatomsDetectable amount of terbium was incorporated in diatoms, suggesting that the diatoms utilized silicon in quartz particles. However, it was found that some replicate expriments are required to confirm the results.