Study on ocean acidification and mass extinction of biosphere in the earth surface's environmental system

2014 Fiscal Year Final Research Report

• Project/Area Number: 22224009
• Research Category: Grant-in-Aid for Scientific Research (S)
• Allocation Type: Single-year Grants
• Research Field: Geology
• Research Institution: The University of Tokyo
• Principal Investigator: KAWAHATA Hodaka 東京大学, 大気海洋研究所, 教授 (20356851)
• Co-Investigator(Kenkyū-buntansha): SUZUKI Atsushi 独立行政法人産業技術総合研究所, 地質情報部門, 研究グループ長 (60344199) ; YAMAOKA Kyoko 独立行政法人産業技術総合研究所, 地質情報部門, 研究員 (39610399) ; MAYURI Inoue 岡山大学, 理学部, 助教 (20451891) ; NISHI Hirosi 東北大学, 学術資源研究公開センター, 教授 (20192685)
• Project Period (FY): 2010-04-01 – 2015-03-31
• Keywords: 海洋酸性化 / 二酸化炭素 / pH / 生物起源炭酸塩 / 精密飼育実験 / 河川水 / 化学風化 / 栄養塩

Outline of Final Research Achievements

This study focused on reevaluating conditions based on samples taken from the Ayeyarwady, Mekong, and Chao Phraya rivers. Our calculations suggest that chemical weathering and associated CO2 uptake in the Himalayas have played a minor role in long-term global cooling in the past. In contrast, soil respiration in these river basins, which have thick, well-developed soil layers, increases river water pCO2, and on a short timescale these rivers function as strong sources of CO2 to the atmosphere.
In Paleocene/Eocene (P/E) transition at 56-57 Ma, a pH decrease was very likely responsible for the emergence of agglutinated foraminiferal fauna as calcareous fauna was eliminated by acidification. Current global emission rate (~7.3 peta gC yr-1) of anthropogenic carbon input is approximately 30 times. The results give an implication that the deep sea benthic fauna will be threatened in future in combination with ocean acidification.

Free Research Field

数物系科学・地球惑星科学・地質学・環境地質