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AEI
Aquaculture Environment Interactions

    AEI prepress abstract   -  DOI: https://doi.org/10.3354/aei00349

    Carbon budgets of two typical polyculture pond systems in coastal China and their potential roles in the global carbon cycle

    Dongxu Zhang, Xiangli Tian*, Shuanglin Dong, Yan Chen, Jie Feng, Rui-Peng He, Kai Zhang

    *Corresponding author:

    ABSTRACT: Although an indispensable component of aquatic ecosystems, the role of aquaculture systems in the global carbon cycle is poorly understood to date. In this study, the carbon budgets in a polyculture system of swimming crabs Portunus trituberculatus with kuruma shrimp Marsupenaeus japonicus) (PM) and that of swimming crabs with kuruma shrimp and short-necked clams Ruditapes philippinarum (PMR) were studied during the farming season (125 d in total). The results showed that the carbon input via water was the main input (55.06% in PM and 62.50% in PMR), followed by that via the feeds. PM absorbed 21.55 g C m–2 across the air–water interface during the farming season, accounting for 13.27% of the total input. The carbon output via water was the main output in both PM and PMR, accounting for 89.17 and 46.43%, respectively. PMR emitted 53.00 g C m–2 into the atmosphere during the farming season, accounting for 32.53% of the total output. The carbon output by harvested animals in PMR accounted for 19.48% of the total output, which was much higher than that from harvested animals in PM (5.71%). Carbon accumulation in the sediment in PM was significantly higher than that in PMR (p < 0.05), but the value of both represented a small portion of the total output. Clam farming in the polyculture system profoundly altered the carbon budgets by changing the CO2 flux direction, reducing carbon accumulation in water and sediments and increasing the carbon output by harvested animals. In terms of the global warming potential which was calculated from the results of CO2 and CH4 fluxes across the air–water interface, PM had potential for mitigating the greenhouse effect on the 20 yr horizon, while PMR exacerbated global warming. On the condition of current research, PM acted as a net carbon sink in the global carbon cycle, while PMR acted as a carbon source.