Elucidation of the key processes of carbon sequestration in coastal sea

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K14511
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 40030:Aquatic bioproduction science-related
• Research Institution: Nagasaki University
• Principal Investigator: TAKASU Hiroyuki 長崎大学, 水産・環境科学総合研究科(環境), 助教 (00774803)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: 溶存態有機物 / 炭素隔離 / 栄養塩

Outline of Final Research Achievements

Nutrients amendment incubation experiments using coastal seawater were conducted to confirm whether nutrients are limiting factors for microbial decomposition of refractory dissolved organic carbon (RDOC). Amount of RDOC was not significantly different between nutrients amended and non-amended bottles. However, concentrations of dissolved protein in nutrients amended bottles were significantly lower than those in non-amended bottles at the end of experiments, suggesting that nutrients addition promoted bacterial decomposition of protein in refractory fraction. In nutrients non-amended bottles, other organic compounds with same carbon equivalent with decomposed protein in the nutrients amendment bottles may be decomposed, and thus, significant differences of RDOC between nutrients amended and non-amended bottles may be not found. Thus, influences of nutrients amendment on microbial decomposition of organic matter may differ among types of organic compounds.

Free Research Field

生物地球化学、海洋生物環境学

Academic Significance and Societal Importance of the Research Achievements

海洋生物を介して海域に貯留される炭素は、「ブルーカーボン」と呼ばれ、陸上植物の貯留する炭素に匹敵するかそれ以上であると試算されており、COP21で合意されたパリ協定においてもブルーカーボンは温室効果ガスの吸収、貯蔵庫の候補として位置付けられている。本研究では、沿岸域の溶存態有機炭素の細菌分解・生成に対する栄養塩添加の影響の一端を明らかにすることができた。これは、海洋細菌群集によるブルーカーボンの生成メカニズムの解明に資する成果であり、ブルーカーボンの生成による炭素隔離能力の強化を図る上で重要な情報であると考えられる。