A Preliminary Study On Monitoring And Evaluation Of Environmental Effects Of Air-lift Artificial Upwelling

In the surface waters, the distribution of nutrients is extremely high in coastal waters of the East China Sea, but only in the narrow sea shore in50m deep shelf area with low nutrient content, unable to meet the needs of plankton. Deep sea water temperature is low and rich in nutrients. It can be raised to the surface by upwelling, so you can change the distribution of temperature and nutrients around the water, improving the marine environment and primary productivity. Artificial upwelling is a hot domestic marine scientific research recently, but literature and research on how to monitor and evaluate is relatively rare. In this paper, We carry out monitoring and assessment of environmental effects of aitificial upwelling from the following aspects:In order to verify the impact of the "Shallow Gas Injection Theory" and enhance the environmental effects of upwelling, two lake trials were carried out in Thousand-island Lake, Zhejiang Province by using single-point and three-dimensional monitoring theories respectively. Temperature, dissolved oxygen and chlorophyll along with other parameters under different nozzle shape, injection volume and diameter conditions are measured successfully.Temperature and nutrients are the best indicator and important environmental parameters of water. On the basis of the lake trial on monitoring, simulation of temperature and nutrient of the water around the system is studied in computational fluid dynamic theory by fluent. Simulation of water is divided into two cases, the lake and the sea. VOF model analysis on temperature of upwelling process is used in the lake case. Simulation result of temperature is consistent with the experimental result and the simulation model predicts the temperature of the surrounding water well. In seawater case, the transmission model component analysis was used on temperature and nutrient simulation, simulation shows that the temperature and the mixed layer of nutrients can be controlled by varying the flow rate the speed of currents.Chlorophyll a is also an important parameter to assess the primary productivity of waters by artificial upwelling. In order to assess the primary productivity, artificial neural network modeling is used. The temporal evolution models of chlorophyll a, dissolved oxygen, depth, temperature, salinity and pH are established respectively. A new assessment method of environmental effects in marine artificial upwelling is also proposed.Lake trial, simulation and modeling of air-lift artificial upwelling all have already been carried out successfully. The effect and impact on the environment of air-lift artificial upwelling were fully validated by the result of monitoring tests, which provide a strong reference to the environmental effects assessment of aitificial upwelling and sea trials in the future.