Relationship between nitrogen and carbon stable isotope effects and their sustainable food chains in marine ecosystems

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K19862
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 63:Environmental analyses and evaluation and related fields
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: Aita Maki 国立研究開発法人海洋研究開発機構, 地球環境部門(地球表層システム研究センター), グループリーダー (90463091)
• Co-Investigator(Kenkyū-buntansha): 石井 励一郎 総合地球環境学研究所, 研究基盤国際センター, 准教授 (40390710)
• Project Period (FY): 2018-06-29 – 2023-03-31
• Keywords: 同位体効果 / アミノ酸組成 / 窒素・炭素安定同位体比 / 同位体濃縮 / 代謝理論モデル / マイワシ / カタクチイワシ / 給餌実験

Outline of Final Research Achievements

To understand the mechanism of "fluctuation" in various isotope effects occurring in the organisms' bodies, we conducted feeding experiments on Japanese sardines and anchovies using food with known carbon and nitrogen stable isotope ratios. As a result, we succeeded in capturing the process in which the isotope ratio of the ovary increased as yolk formation progressed. In contrast, isotope ratios of the muscle and liver did not change. From this fact, we speculated that wild Japanese sardines accumulate nutrients in their muscles during their migration from the foraging grounds to the spawning grounds, where they efficiently and stably distribute as well as utilize the accumulated nutrition along with the ingested nutrition to the gonads to form the ovaries.

Free Research Field

海洋物質循環、同位体生態学、生物地球化学

Academic Significance and Societal Importance of the Research Achievements

海域規模の海水温の変動と小型浮魚類の数十年規模の変動が密接に関連していることは知られているが、自然界の代謝系の機能的適応戦略、特に加入量の予測に不可欠な産卵親魚群の繁殖能力に関する理論的・実験的な検証は未だ十分ではない。本研究で捉えた代謝系ダイナミクスについて、今後、アミノ酸レベルまで解明し、規格化することができれば、代謝ダイナミクスの解明を通じて、生物生理学研究の発展のみならず、水産海洋学分野においては新たな資源管理方策の提示・導入などにも貢献できると考えられる。