Community shift from hard to soft corals in a CO2 seep

2020 Fiscal Year Final Research Report

• Project/Area Number: 16H01766
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Environmental dynamic analysis
• Research Institution: The University of Tokyo
• Principal Investigator: Kayanne Hajime 東京大学, 大学院理学系研究科(理学部), 教授 (60192548)
• Co-Investigator(Kenkyū-buntansha): 波利井 佐紀 琉球大学, 熱帯生物圏研究センター, 准教授 (30334535) ; 佐藤 縁 国立研究開発法人産業技術総合研究所, エネルギー・環境領域, 研究グループ長 (40357132) ; 栗原 晴子 琉球大学, 理学部, 助教 (40397568)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 海洋酸性化 / サンゴ礁 / ソフトコーラル / 造礁サンゴ

Outline of Final Research Achievements

Three species of soft corals of genera Sarcophyton (mainly Sarcophyton elegans), Sinularia, and Lobophytum were identified in the coral reef flat with CO2 seep on Iwotoorishima Island. A significant decrease in coverage of both soft and hard corals occurred accompanying with mass bleaching event in 2016 and 2017. Subsequently, Sarcophyton along LN-15 close to the CO2 seep, and hard corals along LN-8, 200 to 300 m away from the seep, have recovered. On the other hand, at LN-17 at the site of CO2 seep, certain species of reef-building corals such as Porites, Goniastrea, Goniopora, and Favia (currently renamed as Dipsastraea) have been recruited; these corals may have acquired high CO2 tolerance.
Nanipora, a recently discovered species of Octocoral, was found to be predominantly distributed near CO2 seep, suggesting that Nanipora may have evolved to be particularly adapted to high CO2 environments.

Free Research Field

地球システム学

Academic Significance and Societal Importance of the Research Achievements

式根島のCO2湧出口において生物分布とその応答を調査している，筑波大学と研究連絡を行って，硫黄鳥島と式根島との比較を行った．さらに，国内の酸性化モニタリングネットワークに参加して，亜熱帯海域における酸性化モニタリングの代表地点として登録した．