2001 Fiscal Year Final Research Report Summary
Cultivation of diatoms using Tb-doped silicate minerals to characterize silicon utilized by diatoms
| Project/Area Number |
12640477
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
地球化学
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
AKAGI Tasuku Tokyo University of Agriculture and Technology, Faculty of Agriculture, Professor, 農学部, 教授 (80184076)
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| Co-Investigator(Kenkyū-buntansha) |
OGAWA Hiroshi Tokyo University, Marine research institute, associate professor, 海洋研究所, 助教授 (50260518)
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| Project Period (FY) |
2000 – 2001
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| Keywords | diatoms / speciation of sillcon / Skeletonema / cultivation experiment / carbon geocycle / terbium |
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| Research Abstract |
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 analysis
Proliferation 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 apparatus
A 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 analysis
Reference 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 cultivation
Proliferation 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 diatoms
Detectable 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.
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