Development of a chemical imaging method of marine particles using optical sensing techniques

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K13934
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 24020:Marine engineering-related
• Research Institution: Japan Agency for Marine-Earth Science and Technology (2019-2021); The University of Tokyo (2018)
• Principal Investigator: Takahashi Tomoko 国立研究開発法人海洋研究開発機構, 超先鋭研究開発部門(超先鋭技術開発プログラム), Young Research Fellow (20806301)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: コヒーレント反ストークスラマン散乱 / マイクロプラスチック / 動的粒子化学イメージング / 海中粒子

Outline of Final Research Achievements

In this project, chemical imaging techniques of flowing particles in water were investigated aiming at in-situ continuous monitoring of deep-sea micro particles. For fast in-flow detection of microplastics and microalgae with high spatial and temporal resolutions, a method based on coherent anti-stokes Raman scattering (CARS) detection, was proposed. Different plastic particles with sizes of several tens of micrometers were selectively detected in a high-speed flow. In-flow classification of microplastic and alga particles was also successfully performed by the simultaneous detection of CARS and two-photon excited auto-fluorescence signals. In addition, an integrated method of digital holography and Raman spectroscopy was investigated, and the morphological and chemical analysis of plastic, organic and inorganic particles was demonstrated in a large volume of water using a compact system.

Free Research Field

水中分光

Academic Significance and Societal Importance of the Research Achievements

主たる海中粒子である有機物は深海の貴重な栄養源だが、一方で生態系に影響を及ぼしうるマイクロプラスチックも深海で多く発見されている。現状では海中粒子の種類ごとの分布はサンプリングでしか得ることができず、微小粒子や特に存在密度の少ない深海粒子については限られた情報しかないが、本研究により数十マイクロメートルの微小粒子を流れの中で連続的に化学モニタリングする計測手法を提示でき、深海環境影響評価の革新的なツールとして期待できる。今後手法を海中現場での調査に応用することにより、今までよりはるかに高い空間・時間分解能での調査が可能になり、栄養塩循環への新たな知見やプラスチック汚染のコントロールにつながる。