The Application of Seabed Silt in the Preparation of Artificial Algal Reefs

Abstract

Large amounts of silt have been deposited on the seabed in China’s coastal areas due to intensive coastal development and marine raft aquaculture, which are the main causes of local marine environmental disasters. In this study, seabed silt was tested as a potential raw material for artificial reefs. The silt was mixed with cement in four proportions to create concrete specimens for use in silt artificial reefs (SARs). The compressive strength development and nutrient dissolution were examined in the SAR specimens. The hydration products of the SAR paste were investigated through X-ray diffraction (XRD), scanning election microscope (SEM), and differential scanning calorimetry (DSC) techniques. The results showed that the compression strength of the SAR specimens was inversely proportional to their seabed silt content. The SAR specimens were able to continuously dissolve nitrogen-containing nutrients. The presence of Ca(OH)2, commonly found in traditional concrete, was not detected, which may help improve the seaweed adhesion and biological effects of artificial reefs. The effective utilization of seabed silt could serve to restore and improve the marine ecological environment.

Comparative Analysis of the Ecological Succession of Microbial Communities on Two Artificial Reef Materials

“…In contrast, concrete is a more suitable material for ARs due to its density, strength and durability (>30 years) [ 7 , 54 ], but has higher construction costs than other materials [ 52 ]. The addition of industrial waste (e.g., slag and fly ash), biogenic material (e.g., oyster shells) and seabed silt into AR concrete is also a potential strategy for environmental remediation [ 55 ].…”

The Hydrodynamic Characteristics Induced by Multiple Layouts of Typical Artificial M-Type Reefs with Sea Currents Typical of Liaodong Bay, Bohai Sea

“…To date, the most common methods to investigate the hydrodynamic characteristics of artificial reefs relate to numerical simulations or experimental tests conducted within wind tunnel or flumes, where particle image velocimetry (PIV) techniques can be applied [25][26][27][28][29][30][31]. Previous studies conducted by adopting these methods have highlighted a list of factors that can alter the hydrodynamic characteristics of artificial reefs, and this includes the original flow field and the existing terrain, the location of the new artificial reefs placed, the manufacturing materials, the shape and the structure, the opening ratio and the upstream area of the reefs, as well as the number of elements [32][33][34][35][36][37][38]. Most of the studies available in literature refer to single artificial reefs, however, when these are implemented within marine regions across the world, their setup involves groups of them which form proper reef belts, and there is a need to accurately assess the performance of them as a full unit rather than their independent performance.…”