Fractionation of carbon forms in sedimentary layers and typification of carbon stock effects in urban coastal areas

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04710
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22040:Hydroengineering-related
• Research Institution: Osaka Metropolitan University (2022); Osaka City University (2020-2021)
• Principal Investigator: Toru Endo 大阪公立大学, 大学院工学研究科, 准教授 (00527773)
• Co-Investigator(Kenkyū-buntansha): 中下 慎也 広島大学, 先進理工系科学研究科(工), 助教 (90613034)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 大阪湾 / 堆積物 / 炭素貯留 / 残存性有機炭素 / 生分解性有機炭素 / 無機炭素

Outline of Final Research Achievements

Blue carbon is attracting attention as a measure to reduce greenhouse gas emissions, and it is desirable to elucidate and quantify the effects of carbon sequestration in coastal areas. The objective of this study was to clarify the morphological carbon deposition in Osaka Bay. First, as a simple analytical method for morphological carbon in lieu of biodegradation tests, we focused on the fact that the combustion temperature of carbon compounds differs depending on their composition, and developed a method that can fractionate organic matter in sediments into biodegradable and persistent organic carbon by identifying the combustion temperature of biodegradable organic carbon. Subsequently, we measured the amount of carbon by morphology in sediments collected in the sea area and along the coast of Osaka Bay, clarified the amount of residual organic carbon stored in the entire Osaka Bay area, and organized the carbon deposition by morphology for each coastal profile.

Free Research Field

沿岸環境工学

Academic Significance and Societal Importance of the Research Achievements

ブルーカーボン生態系として、マングローブ林や海草・藻場、塩性湿地など植生を含む沿岸生態系の重要性が世界的に認知されている。本研究では干潟や砂浜、港湾海域などの都市沿岸部における炭素貯留効果に着目しており、本研究の成果は我が国に多く分布する海岸線の新たな生態系価値を見出すとともに、海岸線保全の重要性の向上に貢献する。また、海底に堆積する有機物の一部は、生物の同化にともなう呼吸や無機化により再び回帰するため、有機物そのものは正確なストックとして評価できない。本研究では、堆積物中に残存する難分解有機炭素の簡易分析手法を構築しており、今後は本手法により多くのサンプル調査が可能となり実態解明に貢献する。