Evaluation of the groundwater impact on the diversity production in coastal environment: Toward the conservation of seagrass ecosystem services

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H03411
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 64040:Social-ecological systems-related
• Research Institution: Okayama University
• Principal Investigator: Saito Mitsuyo 岡山大学, 環境生命科学研究科, 准教授 (20512718)
• Co-Investigator(Kenkyū-buntansha): 岩田 徹 岡山大学, 環境生命科学研究科, 准教授 (10304338) ; 大久保 賢治 岡山大学, 環境生命科学研究科, 特命教授 (50135612) ; 小野寺 真一 広島大学, 先進理工系科学研究科(総), 教授 (50304366)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 地下水 / 沿岸環境 / 多様性 / 藻場 / 海底湧水

Outline of Final Research Achievements

Seagrass-seaweed meadows (hereafter SSM) are regarded as an important coastal ecosystem with several ecosystem services. In this research, we aimed to evaluate the effect of groundwater on the diversity production in the coastal environment of islands in Seto Inland Sea for the conservation of SSM. We succeeded in mapping the spatial distribution of seagrass-seaweed meadows on an intertidal beach scale by the imagery analysis using UAV (Unmanned Aerial Vehicle; drone), which hasn’t been well examined before. We also evaluated the effect of submarine groundwater discharge (SGD) on the spatial distribution, constituent species, and the habitat of SSM, and found that SGD-derived nitrogen significantly influenced the spatial variation and biomass of green algae (e.g. Ulva). Besides, it was also demonstrated that SGD-derived nutrients to the coastal area tend to increase after extreme rainfall events.

Free Research Field

沿岸環境科学

Academic Significance and Societal Importance of the Research Achievements

本研究の学術的意義は，藻場の保全にとって重要な水温や塩分，栄養塩環境のバリエーション，すなわち沿岸環境の多様性形成に及ぼす地下水（海底湧水）の影響を明らかにする点にある．地下水を含む陸側の要因が沿岸藻場に及ぼす影響は従来ほとんど明らかにされておらず，得られる結果は沿岸域の複雑な物質循環の解明にとって重要かつ新規性の高い知見となる．
また，社会的意義として，本研究の成果をもとに，将来的には藻場の保全や再生ポテンシャルの高いエリアの提案に加え，新たな保全対策の一つとして，陸域地下水の適正利用などの提案が可能になると考えられる．したがって，自然環境と人間との共生に向けた世界的な波及効果が期待できる．