SGD studies in Jiaozhou Bay

In Jiaozhou Bay, (Wang et al. , 2014) studied the distribution characteristics of radium isotopes in water bodies to prove that the activity of 224Ra and 226Ra may be influenced by local lithology, human activities and groundwater recharge. In addition, the activity distribution of224Ra in Jiaozhou Bay decreased gradually with the increase of offshore distance, while the activity of226Ra remained at a high level in the whole jiaozhou Bay, which provided the basis for the follow-up study.
(Yuan et al. , 2016) estimated SGD flux by using the mass balance method of 226Ra. The discharge flux of submarine groundwater in Jiaozhou Bay from September to October in 2011 was 7.85*106m3/d, while that in Jiaozhou Bay from April to May in 2012 was 4.72*106 m3/d. Yan Zhang (2017) improved this model by fully taking the tracer loss in seawater caused by RSGD into account, especially when the concentration difference between offshore seawater and groundwater is not large enough. The result is 1.21*107 to 2.17*107m3/d, which is 1.34~1.44 times of the previous model.
In 2017, (Qu et al. , 2017)used generalized darcy’s law to describe the cross section flow dynamics, seawater exchange rate of groundwater, SGD related nutrient flux and nutrient flux (DIN and DIP) of four different wetland types. He calculateed the SGD exchange rate was 3.6*10-3 to 7.6 cm/d, which reached the maximum in the sandy coastal zone. This phenomenon proves that the rate of SGD has good correlation with hydraulic conductivity. In addition, (Yuanet al. , 2018) studied the influence of SFGD on the seasonal and spatial variation, distribution and flux of dissolved and granular nutrients in Jiaozhou Bay, proving its important role in the ecosystem of Jiaozhou Bay.
Furthermore, (Yang et al. , 2013) proposed a biogeochemical model and a new definition of marine bay water exchange time. He used the ratio of non-conservative substance Si and N as tracer of water in the bay. According to the definition of water exchange completed in the Bay and the filling and empting principle of the bay, he calculated that the water exchange time of Jiaozhou Bay was between 12 and 15 days, and the average value was 12.5 days. This method does not need to be based on the dynamics of power flow, and it is not affected by power flow parameters and variables. Therefore, as long as the new definition, principle, method and biogeochemical model are used to study the water exchange capacity of Jiaozhou Bay, the water exchange time of Jiaozhou Bay can be calculated. The results obtained are basically similar to those calculated by box model and numerical model by State Oceanic Administration and Qingdao Aquatic Products Administration (1998).