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).