Evaluation of species specific elemental quota using new trace element analysis methods for individual microalgal cell

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H03585
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: The University of Tokyo
• Principal Investigator: Itai Takaaki 東京大学, 大学院理学系研究科(理学部), 准教授 (60554467)
• Co-Investigator(Kenkyū-buntansha): 平田 岳史 東京大学, 大学院理学系研究科(理学部), 教授 (10251612) ; 高橋 嘉夫 東京大学, 大学院理学系研究科(理学部), 教授 (10304396) ; 砂村 倫成 東京大学, 大学院理学系研究科(理学部), 助教 (90360867)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 放射光マイクロビーム / 微細藻類 / 生物必須微量元素 / 湖沼 / カイアシ / X線吸収微細構造

Outline of Final Research Achievements

With the aim of establishing a method for analyzing the trace element composition of a single microalgae cell, we have been working on methods using synchrotron radiation X-ray fluorescence analysis and its applied research. Specific achievements include: (1) establishing a method to analyze the concentrations and relative ratios of Fe, Cu, and Zn in microalgae approximately 20 μm in size at the individual level; (2) elucidating the controlling factors of intracellular element concentrations by comparing the trace element concentrations in diatoms from multiple eutrophic lakes (available element concentrations in water and cell density); and (3) analyzing 1-μm-level microalgae by STXM to evaluate the applicability of elemental distribution and speciation of carbon, (4) achieving chemical speciation analysis of Fe in mesoscale zooplankton (copepods) at the individual level using chelate washing and X-ray absorption fine structure analysis.

Free Research Field

環境地球化学

Academic Significance and Societal Importance of the Research Achievements

本研究で取り組んだ手法は、海洋分野では北米の研究者1グループが進めてきた内容で、国内でその応用性を実証する取り組みはなかった。今回の研究成果が、国内の陸水学・海洋学コミュニティに波及すれば、水圏生態学の研究の深化につながり、気候変動に対する生態系応答などの課題にも貢献できると考えている。