Guangdong Ocean University, China (People's Republic)
Abstract: Ecosystems around the globe are increasingly challenged by climate change, which is widely attributed to greenhouse gas emissions. Strategic plans and management have been carried out in many countries for reducing greenhouse gas emissions and developing various forms of carbon sink storage. The ocean has considerable potential to function as a carbon sink, absorbing anthropogenic carbon dioxide and buffering the effects of climate change. In addition to forest and grassland ecosystems, the importance of carbon sequestration by marine organisms as an ecological carbon sink has become increasingly recognized, and marine shellfish play a significant role in marine organic carbon storage. However, how the mariculture of shellfish can be better used to increase the ocean carbon sink needs long-term assessment. In this study, we examined the species composition, production, and carbon sink capacity of six major mariculture shellfish species (clam, ark clam, razor clam, mussel, oyster, and scallop) in nine coastal provinces of China from 1981 to 2020. Spatiotemporal distributions of annual production and carbon sink of the six shellfish species in the nine provinces were analyzed. Effects of species composition and production on the carbon sink capacity of shellfish mariculture were assessed using logarithmic mean Divisia index (LMDI) decomposition approach.
Results showed that both annual production and carbon sink of the six mariculture shellfish species in the nine coastal provinces of China increased consistently from 1981 to 2020, with shellfish production increasing from 9.80 × 104 t to 1.35 × 107 t and carbon sink increasing from 1.00 × 104 t to 1.17 × 106 t. Among the six shellfish species, oyster, clam and scallop were the main source of removable carbon sinks for shellfish mariculture in China. The annual production and carbon sink capacity of mariculture shellfish resources in China varied geographically among species, with scallop and clam contributing most in northern China provinces and oyster and clam contributing most in southern China provinces. Among the nine provinces, Shandong, Fujian and Liaoning had the highest carbon sink of shellfish mariculture, whereas Jiangsu, Hebei and Hainan showed the lowest carbon sink, although Hebei and Jiangsu exhibited the highest growth rate (14% and 12%, respectively). The LMDI decomposition approach suggested that annual production played a more important role than species composition in influencing the carbon sink capacity of shellfish mariculture in China. Based on the results, we proposed a scheme that optimally and more sustainably manages mariculture shellfish resources in China.
