Japan Geoscience Union Meeting 2023

Presentation information

[E] Oral

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

[A-CG35] Global Carbon Cycle Observation and Analysis

Thu. May 25, 2023 10:45 AM - 12:15 PM 104 (International Conference Hall, Makuhari Messe)

convener:Kazuhito Ichii(Chiba University), Prabir Patra(Research Institute for Global Change, JAMSTEC), Akihiko Ito(National Institute for Environmental Studies), Chairperson:Kazuhito Ichii(Chiba University)

11:45 AM - 12:00 PM

[ACG35-10] Temporal variations of air-water carbon dioxide fluxes in tropical and subtropical clam and fishponds in Taiwan

*Veran Weerathunga1, Li-Lian Liu1, Fei-Ling Yuan1, Sheng Xiang Xu1, Kai-Jung Kao1, Kuei-Chen Huang1, Wei-Ming Chen1, Wei-Jen Huang1 (1.Department of Oceanography, National Sun Yat-sen University, Kaohsiung, Taiwan)


As aquaculture will continue to expand more on land than those in the sea, the role of these inland waters in air-water carbon dioxide (CO2) gas exchange has gained increasing attention due to the issue of "carbon tax". However, studies focusing on CO2 gas exchange in clam and fishponds are rare. Here, we measured the partial pressure of CO2 at the air-water interface by deploying a home-made CO2 buoy in three clam and three fishponds on the west coast of Taiwan for 24 hours from April 2021 to June 2022, covering three culture stages: stocking, middle, and harvesting stage. We observed both diurnal and culture stage-dependent changes in CO2 flux. In all ponds, fluxes were stronger during the daytime due to higher wind speeds compared to nighttime. Clam ponds acted as a sink of CO2 into the atmosphere during the stocking stage but turned into a source during the harvesting stage. Fishponds acted as a source of CO2 during all stages, but flux became stronger when reaching the harvesting stage. Overall, clam ponds acted as a weak sink of atmospheric CO2 (1.0 ± 18.8 mmol.m-2.d-1), while fishponds were a source of atmospheric CO2 (15.9 ± 21.3 mmol.m-2.d-1). We suggest that management practices based on the species and culture cycle along with diurnal variations should be considered to estimate the air-water CO2 flux in an aquaculture pond.