講演情報
[ACG67-P05]海洋昇温および酸性化に対する生物炭素ポンプの生物地球化学的応答：C-LIFEプロジェクトの概要
*野口 真希1、田所 和明2、木元 克典1、鋤柄 千穂1 (1.海洋研究開発機構 地球表層システム研究センター、2.水産研究・教育機構 水産資源研究所 海洋環境部)
キーワード：
海洋酸性化、生物ポンプ、石灰化プランクトン、動的環境適応モデル
Human activities have led to the release of substantial amounts of carbon dioxide (CO2) into the atmosphere and oceans, resulting in global warming, ocean deoxygenation, and acidification. These stressors have profoundly affected plankton, which form the foundation of the marine food web and drive the biological carbon pump, thereby posing serious threats to marine ecosystems and human society. Among planktonic organisms, calcifying species are particularly vulnerable to ocean acidification. Calcareous foraminifera have already exhibited signs of shell dissolution in response to acidification. Such disruptions at lower trophic levels are expected to cascade throughout marine ecosystems. Long-term observations at time-series station K2 (47N, 160E) in the northwestern North Pacific also confirm the progression of ocean acidification.
Since 2001, the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has conducted continuous observations at station K2, located off the Kamchatka Peninsula where the biological carbon pump is particularly active. Analyses of seawater pH reveal a clear trend toward acidification over the past two decades (Wakita et al., 2017; 2026). Micro X-ray computed tomography (MXCT) analyses of calcareous foraminifera collected from this region indicate shell degradation in approximately 20% of nearly 100 examined individuals. Complementary laboratory culture experiments on gastropod larvae under simulated future ocean acidification conditions demonstrate that progressive acidification results in thinner and smaller shells, reduced shell density, and increased fragility. Furthermore, gene expression analyses reveal a contraction of the cellular regions responsible for shell formation (Shimizu et al., 2025). These findings suggest that in future oceans, calcifying organisms may encounter challenges not only in maintaining existing shells but also in forming new ones, raising concerns about their survival and population persistence.
To address these emerging risks, the C-LIFE project (Carbon cycle and Lower trophic level oceanic organisms Investigation for Future Environments [JPMJCR24J1]), supported by the Japan Science and Technology Agency (JST) CREST program, was launched in October 2024. The objective of C-LIFE is to advance beyond the limitations of traditional chemical equilibrium methodologies by developing a novel global three-dimensional ocean ecosystem model incorporating a flexible plankton functional type scheme (FlexPFT). The FlexPFT framework integrates dynamic adaptive processes to evaluate ecosystem responses under multiple stressors.
By integrating molecular biological data, laboratory experiments, and long-term field observations into a three-dimensional ocean ecosystem model, the project will quantitatively assess the impacts of anthropogenic CO2-driven warming and acidification on marine ecosystems and the biological carbon pump. Through this integrative approach, C-LIFE aims to advance mechanistic understanding of how ocean acidification may influence the biological carbon pump and future climate-ocean feedbacks.
Since 2001, the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has conducted continuous observations at station K2, located off the Kamchatka Peninsula where the biological carbon pump is particularly active. Analyses of seawater pH reveal a clear trend toward acidification over the past two decades (Wakita et al., 2017; 2026). Micro X-ray computed tomography (MXCT) analyses of calcareous foraminifera collected from this region indicate shell degradation in approximately 20% of nearly 100 examined individuals. Complementary laboratory culture experiments on gastropod larvae under simulated future ocean acidification conditions demonstrate that progressive acidification results in thinner and smaller shells, reduced shell density, and increased fragility. Furthermore, gene expression analyses reveal a contraction of the cellular regions responsible for shell formation (Shimizu et al., 2025). These findings suggest that in future oceans, calcifying organisms may encounter challenges not only in maintaining existing shells but also in forming new ones, raising concerns about their survival and population persistence.
To address these emerging risks, the C-LIFE project (Carbon cycle and Lower trophic level oceanic organisms Investigation for Future Environments [JPMJCR24J1]), supported by the Japan Science and Technology Agency (JST) CREST program, was launched in October 2024. The objective of C-LIFE is to advance beyond the limitations of traditional chemical equilibrium methodologies by developing a novel global three-dimensional ocean ecosystem model incorporating a flexible plankton functional type scheme (FlexPFT). The FlexPFT framework integrates dynamic adaptive processes to evaluate ecosystem responses under multiple stressors.
By integrating molecular biological data, laboratory experiments, and long-term field observations into a three-dimensional ocean ecosystem model, the project will quantitatively assess the impacts of anthropogenic CO2-driven warming and acidification on marine ecosystems and the biological carbon pump. Through this integrative approach, C-LIFE aims to advance mechanistic understanding of how ocean acidification may influence the biological carbon pump and future climate-ocean feedbacks.