The hydrodynamic and transport models were established in Jinmeng Bay (JMB) based on MIKE 21 to study influences of two artificial islands (Lotus Island and Conch Island), and the transport process of green algae was simulated by the Lagrangian particle tracking model. The numerical results reveal that: 1) the velocity in Tanghe estuary was decreased by 50%~80% due to artificial islands; 2) a poor water exchange capacity was formed by the islands and connection road; 3) most green algae remained between the artificial island and the connection road due to hindering of water convection by artificial islands.
The construction of artificial island has become one of the dominant ways for exploring marine resources. It can also resolve the contradiction between population growth and land use. However, the large-scale artificial islands will definitely alter the hydrodynamics in the surrounding area and have impact on the marine environment (Gong et al., 2012; Zhang et al., 2017; Guo L et al., 2009). Jinmeng Bay (JMB) is one of the famous bathing beaches in the Bohai Bay, China. Two artificial islands (Lotus Island and Conch Island) have been built since 2011. With the accelerated process of urbanization in Qinhuangdao, terrestrial pollution, coastal sewage discharge and mariculture have exerted a great influence on the coastal ecological environment. At the same time, the impact of artificial islands on the hydrodynamic environment are obvious, which may result in a lower capacity of water exchange. In 2015, a novel green tide began to emerge in the Bohai Bay and lasted from May to September, threatening the environment and ecosystem of the Beidaihe seaside holiday resort along the coast (Hong et al., 2019; Kuang et al., 2019; Zhao et al., 2017)
Therefore, how to ensure the demands of local economic development and minimum the impact of the artificial islands on marine environment has become a hot research topic. In recent years, many scholars have investigated the artificial island structure, design standard and its influence of construction on surrounding water areas (Lu, 2011). These researches mainly focused on the feasibility analysis of the artificial island (Wang et al., 2012) and impact on the hydrodynamics conditions and erosion-deposition variation of the bay. However, there are a few studies about the impact of artificial island on the hydrodynamics environment and migration of green algae.