Understanding material accumulation mechanisms in surface microlayer during the Oyashio spring diatom blooms

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K17898
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 63040:Environmental impact assessment-related
• Research Institution: Tokai University
• Principal Investigator: NOSAKA Yuichi 東海大学, 生物学部, 講師 (40803408)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 海洋表面マイクロ層 / 透明細胞外重合体粒子 / 植物プランクトン / 親潮域 / 物質循環

Outline of Final Research Achievements

Sea-surface microlayer is the interface between ocean and atmosphere. The accumulation of material in the sea-surface microlayer reduces the rate of material exchange between ocean and atmosphere which could have an impact on predictions of global warming, however there is lack of the knowledge. The massive phytoplankton bloom occurs in the Oyashio region off the coast of Sanriku, and it is possible that a large amount of organic matter accumulates in the microlayer, but not research has been conducted on this region. This study revealed that sugars as derived from phytoplankton accumulate in the microlayer during May 2022 and 2023. Further, the results of the incubation experiments showed that the sugar productivities by phytoplankton varied depending on the light intensity and ultraviolet light.

Free Research Field

生物海洋学

Academic Significance and Societal Importance of the Research Achievements

親潮域の春季植物プランクトン大増殖期において、海洋表面マイクロ層には糖類が蓄積することが判明した。この量はマイクロ層直下の水と比較して8倍にもなる場合がある。また、糖類以外の粒子態物質量を比較した場合にも同様の結果が得られた。したがって、本海域の春季植物プランクトン大増殖期では、二酸化炭素などの地球温暖化に関わる物質の海洋―大気間の交換速度が相対的に低下している可能性がある。このことは地球温暖化予測モデルの精度上昇に対し重要なデータの一つとして学術的にも社会的にも有用である。