Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Evening Poster

A (Atmospheric and Hydrospheric Sciences) » A-CG Complex & General

[A-CG43] Coastal Ecosystems - 2. Coral reefs, seagrass and macroalgal beds, and mangroves

Thu. May 24, 2018 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Toshihiro Miyajima(Marine Biogeochemistry Group, Division of Ocean-Earth System Science, Atmosphere and Ocean Research Institute, The University of Tokyo), Yu Umezawa(Tokyo University of Agriculture and Technology), Atsushi Watanabe(東京工業大学 環境・社会理工学院, 共同), Tomihiko Higuchi(Atmosphere and Ocean Research Institute, The University of Tokyo)

[ACG43-P06] The estimation of CO2 flux in subtropical coastal ecosystems using a numerical model

*Hirotada Moki1, Akio Sohma2, Takashi Shibuki3, Takeshi Toyoda3, Anirban Akhand1, Kenta Watanabe1, Tatsuki Tokoro1,4, Tomomi Inoue5, Hiroya Yamano5, Masayuki Bannno1, Yasuyuki Nakagawa1,6, Hiroyuki Matsuda7, Tomohiro Kuwae1 (1.Port and Airport Research Institute, 2.Osaka City University, 3.Mizuho Information and Research Institute, Inc., 4.National Research Institute of Fisheries and Environment in Inland Sea, 5.National Institute for Environmental Studies, 6.Kyushu University, 7.Yokohama National University)

Keywords:Ecosystem model, Subtropical coastal ecosystem, Air-ecosystem CO2 flux, Carbon burial rate, Future prediction

Coastal ecosystems can play a role in climate change mitigation. One of the appropriate way to accurately quantify and predict the role is the utilization of numerical models. The mitigation effects can be facilitated by CO2 uptake by net primary producers such as mangroves, zooxanthella in coral reef and seagrasses.

In this study, we developed a new ecosystem model that incorporates the biogeochemical processes of mangroves, tidal flats, seagrass meadows, lagoons, and coral reefs. We estimated CO2 fluxes between air and the ecosystems and carbon burial rates in Yaeyama islands, Japan, which is the model site. In the future prediction, we selected two scenarios of representative concentration pathways, low emission (RCP2.6) and high emission (RCP8.5), adopted in IPCC 5th Assessment Report and compared the model results in 2010 and 2100. The output of HadGEM2-ES from CMIP5 models were used as the boundary data.
Our model results showed that the mangrove absorbed CO2 more than other ecosystems because of direct uptake of CO2 from the air. The maximal carbon burial rate was found in the mangrove. Additionally, the inflowing of open waters affected the air-ecosystem CO2 flux and carbon burial rate near the open boundary. We will also present the result of comparisons between the model results and observed data.