Mariculture structure adjustment to achieve China's carbon neutrality and mitigate climate change

Chi Song; Yonglong Xiong; Peng Jin; Yixin Sun; Qiaochu Zhang; Zengling Ma; Guang Gao

doi:10.1016/j.scitotenv.2023.164986

Mariculture structure adjustment to achieve China's carbon neutrality and mitigate climate change

Sci Total Environ. 2023 Oct 15:895:164986. doi: 10.1016/j.scitotenv.2023.164986. Epub 2023 Jun 21.

Authors

Chi Song¹, Yonglong Xiong¹, Peng Jin², Yixin Sun¹, Qiaochu Zhang³, Zengling Ma⁴, Guang Gao⁵

Affiliations

¹ State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China.
² School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China.
³ China-ASEAN College of Marine Sciences, Xiamen University Malaysia, Sepang 43900, Malaysia.
⁴ Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China.
⁵ State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China. Electronic address: guang.gao@xmu.edu.cn.

PMID: 37353016
DOI: 10.1016/j.scitotenv.2023.164986

Abstract

China is responsible for the biggest shellfish and macroalgae production in the world. In this study, comprehensive methods were used to assess the CO₂ release and sequestration by maricultured shellfish and macroalgae in China. Through considering CaCO₃ production and CO₂ release coefficient (Φ, moles of CO₂ released per mole of CaCO₃ formed) in different waters, we find that cultured shellfish released 0.741 ± 0.008 Tg C yr^-1 through calcification based on the data of 2016-2020. In addition to calcification, maricultured shellfish released 0.580 ± 0.004 Tg C yr^-1 by respiration. Meanwhile, shellfish sequestered 0.145 ± 0.001 and 0.0387 ± 0.0004 Tg C yr^-1 organic carbon in sediments and shells, respectively. Therefore, the net released CO₂ by maricultured shellfish was 1.136 ± 0.011 Tg C yr^-1, which is about four times higher than that maricultured macroalgae could sequester (0.280 ± 0.010 Tg C yr^-1). To achieve carbon neutrality within the mariculture system, shellfish culture may need to be restricted and meanwhile the expansion of macroalgae cultivation should be carried out. The mean carbon sequestration rate of seven kinds of macroalgae was 174 ± 6 g m^-2 yr^-1 while some cultivated macroalgae had higher CO₂ sequestration rates, e.g. 356 ± 24 g C m^-2 yr^-1 for Gracilariopsis lemaneiformis and 331 ± 17 g C m^-2 yr^-1 for Undaria pinnatifida. In scenario 0.5 (CCUS (Carbon Capture, Utilization and Storage) sequesters 0.5 Gt CO₂ per year), using macroalgae culture cannot achieve China's carbon neutrality by 2060 but in scenarios 1.0 and 1.5 (CCUS sequesters 1.0 and 1.5 Gt CO₂ per year, respectively) it is feasible to achieve carbon neutrality using some macroalgae species with high carbon sequestration rates. This study provides important insights into how to develop mariculture in the context of carbon-neutrality and climate change mitigation.

Keywords: Carbon neutrality; Carbon sequestration; Climate change; Respiration; Seaweed; Shellfish.

MeSH terms

Carbon Dioxide / analysis
Carbon Sequestration
Carbon* / analysis
China
Climate Change
Seaweed*
Social Conditions

Substances

Carbon
Carbon Dioxide