Abstract
Artificial reefs (ARs) have been widely used to restore the seabed habitat and protect biodiversity. They can effectively increase the dissolved oxygen content in the bottom water layer by their disturbing effect of upwelling and downwelling. The bottom water is prone to hypoxia in summer due to the extreme weather of the global climate and excessive biomass in some marine ranching in northern China. Therefore, how to effectively use the upwelling effect of artificial reefs to alleviate this problem is a necessary subject of research. Generally, ARs are arranged by different intervals in a unit form on the seafloor, and the flow field effect is different from that of the individual reefs. However, few studies have been focused on the effect of layout mode on the flow field of a unit reef (UR). In this paper, we selected the interval between reefs (IR) and the angle of inflow (AI) as the influencing factors to study the flow field effect of UR. The upwelling and wake regions of 64 URs were presented by the efficiency and disturbance indices related to the flow characteristics and proposed an optimal layout mode having the best performance of the upwelling effect. The results showed that the interactions among the AI, the transverse, and longitudinal IRs were significant, and the AI has a significant influence on the flow field. These indices were effective and contribute to the layout optimization of UR. The AI close to 45° has a significant influence on the flow field effect of UR.
Highlights
Artificial reefs (ARs), as man-made permeable structures, are widely used in biodiversity conservation and coastal habitat restoration in marine ranching engineering [1,2,3,4].After the settlement of ARs, a complex hydrodynamic condition is formed in a certain range around the ARs
The evaluation results of the indices of φ1 and φ2 show that the unit reef (UR) formed by the combinations of longitudinal and transverse interval between reefs (IR) with the best benefit of the upwelling region have the better benefit of wake region
Artificial reefs laid on the seafloor can retard the flow to form a slow flow area
Summary
Artificial reefs (ARs), as man-made permeable structures, are widely used in biodiversity conservation and coastal habitat restoration in marine ranching engineering [1,2,3,4]. There is an upwelling region above the AR, which can enhance the exchange and transport of nutrients between the upper and lower water layers and is conducive to the improvement of primary productivity This is one of the basic principles for AR to perform its function on the flow field. Li et al [28] studied the flow field effect of three kinds of tube artificial reef piles under different inlet velocities This form of layout mode is prone to collapse due to the impact of the ocean current. A reasonable combination of ARs, such as IRs and AIs, can improve the overall flow field effect of UR and enhance the disturbance efficiency between the bottom and the upper water layer in the artificial reef area. This study can provide a scientific reference for the layout optimization of UR
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
