Environmental factors controlling accumulation of refractory components of macrophyte contributing to an increase of carbon sequestration to the ocean

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K12295
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: UMEZAWA Yu 東京農工大学, (連合)農学研究科(研究院), 准教授 (50442538)
• Co-Investigator(Kenkyū-buntansha): 渡辺 誠 東京農工大学, (連合)農学研究科(研究院), 准教授 (50612256) ; 堀川 祥生 東京農工大学, (連合)農学研究科(研究院), 准教授 (90637711)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 海草藻類 / 生産量 / 構造物質 / 忌避物質 / 炭素固定 / 分解特性

Outline of Final Research Achievements

Carbon incorporated by macrophyte and sequestrated in the ocean for a long period has been focused on as “blue carbon”. But there is limited knowledge on the primary production (PP) of each species of macroalgae and the decomposition characteristics of the newly produced organic matter under various marine environments. In this study, we accurately evaluated the gross PP by measuring the production of each part of the leaf and stem of Sargassum spp. using the 13C method. We also measured the N content of eelgrass, (Zostera marina) leaves using a portable nitrogen meter and found a negative correlation between N content and the amount of phenol, one of the repellent substances. Furthermore, the incubation experiments of algal tissues with different amounts of repellent substances showed the possibility that the amounts of repellent substances, N&P, in addition to the amounts of structural substances, determine the decomposition characteristics of these plant-derived organic matter.

Free Research Field

生物地球化学

Academic Significance and Societal Importance of the Research Achievements

COP21にて採択されたパリ協定では「温室効果ガスの削減に向けて、生態系吸収源の評価・利用」が明記されており、21世紀後半には、温室効果ガス排出量を生態系が吸収できる範囲に抑えることが掲げれられた。国内でも、近年、「ブルーカーボン（海洋の生物が取り込む炭素）」の活用が着目され、2019年6月の閣議決定では、初めて明記されるに至っている。本研究の成果は、このブルーカーボンの価値の定量的評価に活用できるものであるほか、今後、海草藻場の造成を行っていく上での最適地（水産、環境、防災など様々な観点で）を探っていく際に、有用な科学的知見を提供する。