Development of evaluation method for environmental stresses in brackish water clam Corbicula japonica considering natural environmental changes

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04744
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22060:Environmental systems for civil engineering-related
• Research Institution: Ibaraki University
• Principal Investigator: Fujita Masafumi 茨城大学, 地球・地域環境共創機構, 教授 (60362084)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: ヤマトシジミ / 酸化ストレスマーカー / 成長力 / 開閉運動 / 汽水域

Outline of Final Research Achievements

To investigate biomarkers representing the physiological and biochemical responses of the brackish-water clam Corbicula japonica, we conducted experiments to test different water-temperature levels, salinity levels, food-availability levels, and wastewater exposure. We found that future habitat changes driven by global warming should be closely watched, particularly given that local anthropogenic disturbances further add to natural ones. The results also indicated that the biochemical-level response can be interpreted using individual-level response, but careful attention must be given to over- or underestimation. Additionally, it was obtained that valve opening-closing response measurement using a hall element sensor was useful and valve-opening frequency and valve-opening rate can be good indices.

Free Research Field

水環境工学

Academic Significance and Societal Importance of the Research Achievements

汽水域では自然的要因の変動が大きい。水生生物に対する環境ストレスは自然的要因に人為的要因が上乗せされることから、自然的要因の影響も考慮した評価が重要になる。潮汐にともなう日内変動だけでなく、将来の気候変動による影響にも目を向けると、この視点はさらに重要になる。実環境における水生生物への影響やそれを踏まえた水環境評価・管理へと展開するうえでは、水生生物に対する環境ストレスの影響を分子レベルだけでなく個体レベルの応答も含めて理解することが重要になり、また、生化学的・生理学的応答を総合的に評価する手法も有用となる。