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Sakaguchi J, Nakayama K, Komai K, Kubo A, Shimizu T, Omori J, Uno K, Fujii T. Carbon dioxide uptake in a eutrophic stratified reservoir: Freshwater carbon sequestration potential. Heliyon 2023; 9:e20322. [PMID: 37767477 PMCID: PMC10520817 DOI: 10.1016/j.heliyon.2023.e20322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023] Open
Abstract
Carbon capture and storage due to photosynthesis activities has been proposed as a carbon sink to mitigate climate change. To enhance such mitigation, previous studies have shown that freshwater lakes should be included in the carbon sink, since they may capture as much carbon as coastal areas. In eutrophic freshwater lakes, there is uncertainty about whether the equilibrium equation can estimate the partial pressure of carbon dioxide (pCO2), owing to the presence of photosynthesis due to phytoplankton, and pH measurement error in freshwater fluid. Thus, this study investigated the applicability of the equilibrium equation and revealed the need to modify it. The modified equilibrium equation was successfully applied to reproduce pCO2 based on total alkalinity and pH through field observations. In addition, pCO2 at the water surface was lower than the atmospheric partial pressure of carbon dioxide due to photosynthesis by phytoplankton during strong stratification. The stratification effect on low pCO2 was verified by using the Net Ecosystem Production (NEP) model, and a submerged freshwater plants such as Potamogeton malaianus were found to have high potential for dissolved inorganic carbon (DIC) sequestration in a freshwater lake. These results should provide a starting point toward more sophisticated methods to investigate the effect of freshwater carbon on DIC uptake in freshwater stratified eutrophic lakes.
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Affiliation(s)
- Jinichi Sakaguchi
- Graduate School of Engineering, Kobe University, 1-1 Rokkodai-Cho Nada-Ku, Kobe City, 658-8501, Japan
| | - Keisuke Nakayama
- Graduate School of Engineering, Kobe University, 1-1 Rokkodai-Cho Nada-Ku, Kobe City, 658-8501, Japan
| | - Katsuaki Komai
- School of Earth, Energy and Environmental Engineering, Kitami Institute of Technology, 165 Koen-cho, Kitami, 090-8507, Japan
| | - Atsushi Kubo
- Department of Geoscience, Shizuoka University, 836 Ohya, Suruga-Ku, Shizuoka, 422-8529, Japan
| | - Taketoshi Shimizu
- Water Quality Laboratory, Kobe City Waterworks Bureau, Kobe, Hyogo, 652-0004, Japan
| | - Junpei Omori
- Water Quality Laboratory, Kobe City Waterworks Bureau, Kobe, Hyogo, 652-0004, Japan
| | - Kohji Uno
- Department of Civil Engineering, Kobe City College of Technology, 8-3 Gakuenhigahimachi, Nishi-ku, Kobe City, 651-2194, Japan
| | - Tomoyasu Fujii
- School of Science Education, Nara University of Education, Takabatake-Cho, Nara, 630-8528, Japan
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Nakayama K, Kawahara Y, Kurimoto Y, Tada K, Lin HC, Hung MC, Hsueh ML, Tsai JW. Effects of oyster aquaculture on carbon capture and removal in a tropical mangrove lagoon in southwestern Taiwan. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156460. [PMID: 35660579 DOI: 10.1016/j.scitotenv.2022.156460] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/20/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Blue carbon ecosystems (BCEs) are a promising resource for the mitigation of global warming; however, climate spectrums and anthropogenic activities could influence the fragile balance of BCEs as carbon sinks or sources. We assess how oyster farming affects dissolved inorganic carbon (DIC) and total alkalinity (TA) on CO2 fluxes in a mangrove-dominated lagoon. Water physical, chemical and biological parameters were recorded by in-situ buoys within the lagoon and at its inflow. Structural equation modeling was adopted to clarify the factors/processes controlling the partial pressure of CO2 (pCO2). A three-dimensional environmental model followed by a conceptual DIC model was used to quantify the spatiotemporal patterns of capture and release of DIC and TA by oyster production. The results showed that 49% of TA and DIC released from mangroves was depleted by oyster shell formation. DIC was reduced by algal photosynthesis and algal was served as a food source supporting oyster production. Annual oyster production through phytoplankton photosynthesis accounted for 11% of the atmosphere carbon inflows, suggesting that oyster production served as a significant atmospheric/terrestrial carbon sink in the lagoon. The results indicate that mangroves benefit local oyster production by acting as an important source of DIC and TA, and that the oyster aquaculture contributed to carbon capture in a mangrove-dominated lagoon ecosystem.
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Affiliation(s)
- Keisuke Nakayama
- Graduate School of Engineering, Kobe University, 1-1 Rokkodai-Cho, Nada-Ku, Kobe City 657-8501, Japan.
| | - Yuki Kawahara
- Graduate School of Engineering, Kobe University, 1-1 Rokkodai-Cho, Nada-Ku, Kobe City 657-8501, Japan
| | - Yuki Kurimoto
- Faculty of Engineering, Kobe University, 1-1 Rokkodai-Cho, Nada-Ku, Kobe City 657-8501, Japan
| | - Kazufumi Tada
- Oriental Consultants Co., Ltd., 3-2-18 Nakanoshima, Kita-Ku, Osaka 530-0005, Japan
| | - Hao-Chi Lin
- Graduate School of Engineering, Kobe University, 1-1 Rokkodai-Cho, Nada-Ku, Kobe City 657-8501, Japan
| | - Meng-Chi Hung
- Endemic Species Research Institute, 1 Minsheng E. Rd., Jiji, Nantou 55203, Taiwan, ROC
| | - Mei-Li Hsueh
- Endemic Species Research Institute, 1 Minsheng E. Rd., Jiji, Nantou 55203, Taiwan, ROC
| | - Jeng-Wei Tsai
- Department of Biological Science and Technology, China Medical University, No. 100, Sec. 1, Jingmao Rd., Beitun Dist., Taichung City 406040, Taiwan, ROC.
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Li Y, Yuan L, Cao HB, Tang CD, Wang XY, Tian B, Dou ST, Zhang LQ, Shen J. A dynamic biomass model of emergent aquatic vegetation under different water levels and salinity. Ecol Modell 2021. [DOI: 10.1016/j.ecolmodel.2020.109398] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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