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Ecological engineering by artificial upwelling for enhancing seaweed growth and consequently increasing nutrient removal from seawater has proved promising in combating intense coastal eutrophication. However, a key issue needs to be answered: how much economic and ecological benefit could this engineering bring if it were to be implemented in national aquaculture areas. This study estimated the promoting effect of nutrient concentration change induced by artificial upwelling on kelp growth using a model simulation based on the temperature, light intensity, and nutrient concentration data from three bays in Shandong Province, China&mdash, &nbsp, Aoshan Bay, Jiaozhou Bay, and Sanggou Bay. Our results indicate that ecological engineering by artificial upwelling can increase the average yield of kelp by 55 g per plant. Furthermore, based on the current existing kelp aquaculture area of China and the aquaculture density of 12 plants/m2, we inferred that this ecological engineering could increase the natural kelp yield by 291,956 t and the removal of nitrogen (N) and phosphorus (P) nutrients by 4875&ndash, 6422 t and 730&ndash, 1080 t, respectively.

China is now accelerating the development of an ecological engineering for carbon sequestration in coastal mariculture environments to cope with climate change. Artificial upwelling as the ecological engineering can mix surface water with bottom water and bring rich nutrients to the euphotic zone, enhance seaweed growth in the oligotrophic sea area, and then increase coastal carbon sequestration. However, one of the major obstacles of the artificial upwelling is the high energy consumption. This study focused on the development of energy management technology for air-lift artificial upwelling by optimizing air injection rate. The fundamental principle underlying this technology is that the mode and intensity of air injection are adjusted from the feedback of information on velocity variation in tidal currents, illumination, and temperature of the surface layer. A series of equations to control air injection was derived based on seaweed growth and solar power generation. Although this finding was originally developed for the air-lift artificial upwelling, it also can be used in other areas of engineering, such as water delivery, aeration, and oxygenation. The simulations show that using a variable air injection rate can lift more nitrogen nutrients of 28.2 mol than using a fixed air injection rate of 26.6 mol, mostly with the same energy cost. Using this control algorithm, the changed temperature and dissolved oxygen profiles prove the effective upwelling in the experiments and the average weights of kelp are 33.1 g in the experimental group and 10.1 g in the control group. The ecological engineering was successfully increasing crop yield for carbon sequestration in coastal mariculture environments.