Ecological restoration method for sea island seaweed field based on artificial algal reefs

Abstract

The invention relates to an island seaweed field ecological restoration method based on artificial algal reefs, and belongs to the technical field of marine ecological restoration engineering. The method aims at solving the problems that in the prior art, algae are slowly attached to and grow on natural reefs, attached larvae are disengaged due to algal reef displacement caused by wave scouring, and large prefabricated parts are difficult to hoist and position on the sea and high in risk. According to the technical scheme, the method comprises the steps that an artificial algal reef which is of a hollow structure, provided with holes in the outer vertical face and provided with connecting lug plates and bottom mounting lug plates is prepared; seaweed spores are attached to reefs and grow to a certain length in the water tank of the seedling raising field; after being transported to a target area, the algal reefs are installed in a linkage mode in a low tide period, that is, each algal reef is independently anchored to the seabed through the installation lug plates, and then the adjacent algal reefs are transversely connected through the connection lug plates and the screw rods to form an integral structure. The method is mainly used for rapid construction and ecological restoration of the sea area seaweed field around the island.

Description

An Ecological Restoration Method for Seaweed Farms on Islands Based on Artificial Algal Reefs Technical Field

[0001] This invention belongs to the field of marine ecological restoration engineering technology, specifically relating to a method for ecological restoration of seaweed farms on islands based on artificial algal reefs. Background Technology

[0002] In existing technologies, direct restoration of seaweed beds in natural reef areas surrounding islands typically results in low attachment rates of seaweed spores or larvae to the reef surface, and slow initial growth, leading to a lengthy natural formation cycle for seaweed beds. Furthermore, in open marine environments, especially in areas with significant wave action, even the placement of artificially constructed reefs often presents challenges. Continuous wave erosion can cause reef displacement and capsizing, resulting in the loss of a large number of seaweed larvae before they can firmly establish themselves, making it difficult to guarantee the effectiveness of ecological restoration. On the other hand, using large, integrated prefabricated components to improve stability introduces new construction difficulties. The hoisting and precise positioning of large components at sea is extremely difficult, heavily influenced by wind, waves, visibility, and sea conditions, leading to high construction risks and high costs. How to achieve ecological restoration units that possess effective wave resistance and stability while supporting rapid seaweed attachment and growth in complex open marine environments, while simultaneously ensuring construction feasibility and safety, remains a long-standing challenge in this field. Summary of the Invention

[0003] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0004] Another objective of this invention is to provide an ecological restoration method for seaweed farms on islands based on artificial algal reefs. This method can effectively reduce the displacement of algal reefs and the shedding of seaweed larvae caused by wave erosion, overcome the problem of slow attachment and growth of seaweed on natural reefs, and avoid the disadvantages of difficult positioning and high operational risks of large prefabricated components at sea, thereby promoting the rapid and stable restoration of seaweed farms on islands.

[0005] To achieve these objectives and other advantages of the present invention, a method for ecological restoration of seaweed farms on islands based on artificial algal reefs is provided, comprising the following steps: 1) preparing artificial algal reefs, wherein the artificial algal reefs are constructed of reinforced concrete, the cross-section of the artificial algal reefs is rectangular, and the interior has a hollow structure. At least one outer surface of the artificial algal reef has several holes, and the outer surface of the artificial algal reefs is provided with connecting lugs for interconnection between the reefs. The bottom of the artificial algal reefs is provided with mounting lugs with through holes; 2) placing the artificial algal reefs in a spore attachment tank in a nursery, the spore attachment tanks containing seaweed propagules, so that the spores released by the seaweed propagules attach to the surface of the artificial algal reefs and the inner wall of the hollow cavities, allowing the seaweed to grow to a length of 1-15 cm. cm; 3) Transport the pre-attached artificial reefs to the target island area by boat; 4) Install the artificial reefs in a chain during low tide to complete the ecological restoration of the seaweed beds on the island; The chain installation of artificial reefs specifically includes: 4.1) Place the first artificial reef in the predetermined position, with the outer facade with holes perpendicular to the main wave direction, and drill anchor holes in the natural reef by drilling through the through holes of the mounting ear plates; 4.2) Insert the expansion bolts into the anchor holes, and tighten the first nut to lock the expansion sleeve of the bolt into the hole wall, and then connect the second nut to the expansion bolt to press. 4.3) Install the second artificial reef and align its connecting ear plate with the connecting ear plate of the first artificial reef. The outer facade of the second artificial reef is also perpendicular to the main wave direction. Repeat the drilling of anchor bolt holes in step 4.1) and the expansion bolt fixing process in step 4.2) to complete the anchoring of the second artificial reef. 4.4) Use connecting bolts to pass through the through holes of the connecting ear plates of the two artificial reefs and screw in nuts to connect the two adjacent artificial reefs laterally. 4.5) Repeat steps 4.3) and 4.4) to install and connect the subsequent artificial reefs in sequence to form a laterally interlocked artificial reef group.

[0006] This invention ensures the initial stability of each individual artificial reef unit on the seabed by installing ear plates and anchoring them one by one, effectively resisting wave-induced displacement. Furthermore, by connecting the ear plates and connecting bolts, adjacent reefs are laterally interlocked, linking the dispersed units into a whole. This significantly enhances the structure's overall resistance to wave erosion and torsional strength, thereby greatly reducing the risk of seaweed larvae detaching due to reef movement. Simultaneously, by pre-attaching and growing seaweed propagules to a certain length in a controlled environment before transporting the seaweed-attached reef to the target sea area for installation, a seed population with a certain growth foundation is directly provided. This bypasses the natural bottleneck of seaweed's difficulty in attaching and slow germination on natural hard substrates, accelerating the formation of the seaweed farm. Moreover, the method of this invention uses standardized, modular medium-sized components for on-site assembly and installation, avoiding the technical difficulties and safety risks of directly hoisting and positioning large prefabricated components at sea, making construction operations more flexible and controllable.

[0007] Preferably, the process also includes pretreatment of the artificial algal reef. The specific pretreatment process is as follows: the prepared artificial algal reef is soaked in seawater rich in organic matter for pretreatment for 3-7 days. During the pretreatment, the water in the pretreatment tank is kept circulating to promote the formation of biofilm by microorganisms on the surface of the artificial algal reef and the inner wall of the hollow cavity. Then, the placement operation in step 2) is performed to allow algal spores to attach to the biofilm.

[0008] This invention pre-immerses artificial algal reefs in seawater rich in organic matter, prompting microorganisms to form a biofilm on its surface and internal cavity walls. As a natural bioactive matrix, the biofilm effectively improves the hydrophilicity and microstructure of the concrete surface, providing more and stronger attachment sites for algal spores. At the same time, the organic matter and microbial metabolites contained in the biofilm itself can provide direct nutritional support for the germination and early growth of the attached spores, thereby significantly improving the attachment success rate and colonization stability of the spores, accelerating their early growth rate, and shortening the pre-attachment culture period.

[0009] Preferably, the method for preparing the organic-rich seawater is as follows: Preparation of seaweed extract: Collect local dominant large seaweed, wash and crush it into particles with a diameter of 2-5 mm. Mix the seaweed particles with natural seawater at a mass ratio of 1:10-1:15, soak at room temperature for 48-72 hours, stirring every 8-12 hours. After soaking, filter to remove solid residue to obtain seaweed extract. Preparation of organic matter leachate: Collect surface sediments from natural intertidal mudflats or shellfish farming areas, mix with natural seawater at a volume ratio of 1:5-1:8, stir evenly, and allow to settle for 24-36 hours. Filter the supernatant through a 100-200 mesh sieve to obtain organic matter leachate. Mix the prepared seaweed extract and the prepared organic matter leachate at a volume ratio of 1:1-2:1, and then dilute with 1-2 times the total volume of natural seawater to obtain the organic-rich seawater.

[0010] This invention utilizes extracts prepared from locally dominant seaweeds and mixes them with organic matter leachates from natural sediments to create organic-rich seawater that mimics the natural nutrient cycle and microbial community foundation of the target marine area. The mixture provides a balanced, diverse, and ecologically compatible source of nutrients and microorganisms, enabling the cultivation of structurally stable and highly bioactive pioneer biofilms on the surface of artificial algal reefs. This specially formulated biofilm serves as a seedbed, with nutritional conditions and a microbial environment more suitable for the attachment and germination of seaweed spores, thus effectively improving the overall success rate of subsequent seaweed spore attachment and the robustness of early growth during the pretreatment stage.

[0011] Preferably, during the pretreatment process, intermittent turbulent flow control is implemented for the water circulation in the pretreatment tank. Specifically, a program-controlled circulating water pump is used, with a cycle of 2-4 hours. In each cycle, the water flow velocity is increased to 15-25 cm / s to form a turbulent state for the first 10-15 minutes, and then the water flow velocity is reduced to 5-8 cm / s to maintain a horizontal state until the end of the cycle. The flow velocity in the turbulent state is at least 3 times that in the horizontal state.

[0012] This invention introduces periodically varying flow velocities into the water circulation, effectively disturbing the fluid boundary layer on the surface and within the hollow structure of the artificial algal reef using intermittent turbulence. This enhances water exchange and the transport and infiltration of nutrients on complex surfaces, promoting the uniform distribution and contact of microorganisms and their required substrate. Switching to a laminar flow state then provides a suitable low-shear environment for microbial colonization and stable biofilm growth. This alternating dynamic and static hydraulic control encourages the biofilm to form a more uniform substrate of thickness and density on all exposed surfaces of the artificial algal reef, including the internal cavities. This provides a higher-quality and more consistent attachment foundation for subsequent algal spore attachment, improving the overall success rate of the pre-attachment stage.

[0013] Preferably, during the transportation process in step 3), the pre-attached artificial algal reefs are fixed in layers on the ship-borne transport frame, and a buffer isolation layer made of sodium alginate-based hydrogel is set between the contact surfaces of adjacent artificial algal reefs. The thickness of the buffer isolation layer is 2-5 cm, and its surface is kept moist by an atomization system throughout the transportation process.

[0014] This invention utilizes a sodium alginate-based hydrogel buffer layer between adjacent artificial reefs during transportation. The material's unique flexibility and water retention physically buffer direct collisions and friction between the reefs, effectively preventing the detachment of algae larvae due to mechanical damage. Simultaneously, with continuous atomized humidification, the gel layer maintains a locally high-humidity microenvironment for the algae larvae throughout the transportation process, preventing damage from dehydration. The gel material used is seawater-soluble, quickly and completely dissolving itself after installation and immersion in water. This eliminates the need for additional manual cleaning, maintains construction efficiency, and leaves no solid residue in the target sea area. Therefore, it ensures high survival rates during transportation while also considering ease of construction and environmental friendliness.

[0015] Preferably, the preparation method of the buffer isolation layer is as follows: 6.1) Sodium alginate and starch are dry-mixed at a mass ratio of 3:1 to obtain a mixed dry material; then, the mixed dry material is dissolved in water, and the mass-volume ratio of the mixed dry material to water is 6%-8%. The mixture is stirred at 200-300 rpm for 60-90 min under a water bath condition of 45-55 ℃ to obtain a spinning solution; subsequently, the spinning solution is injected into a 4%-5% calcium chloride aqueous solution by a wet spinning process to solidify and form fibers, which are then woven into a mesh with a pore size of 1 cm × 1 cm. After drying, a soluble fiber mesh is obtained; 6.2) Sodium alginate is dissolved in natural seawater at a mass-volume ratio of 4%-6%, and the solution is continuously stirred to obtain a functionalized gel solution; 6.3) 0.5%-1% of sea salt crystals by total mass are added to the gel solution prepared in step 6.2) to obtain a sea salt gel solution; wherein the particle size range of the sea salt crystals is 0.5-2 mm. The particles are graded according to size, with 0.5-1 mm particles accounting for 60%-70% and 1-2 mm particles accounting for 30%-40%; 6.4) Soluble fiber mesh is placed in a mold, and then sea salt gel solution is injected. Subsequently, cross-linking and curing are carried out by spraying a 2.5%-3% calcium chloride sea water solution. The spraying amount is 0.05-0.08 ml per square centimeter of gel surface, and the cross-linking reaction time is 90-120 s. Finally, a buffer isolation layer with a thickness of 2-3 cm and an internal fiber mesh is formed.

[0016] This invention designs a sodium alginate-based hydrogel with a composite soluble fiber mesh as a buffer layer. The preparation method optimizes the structure and performance of this layer. The internally woven fiber mesh provides necessary skeletal support and integrity, ensuring the shape retention and cushioning effect of the layer during dry handling and transport under pressure. The externally encapsulated functionalized gel provides excellent water retention and flexibility, effectively absorbing impact and maintaining a moist microenvironment. The key lies in the specific particle size of sea salt crystals incorporated into the gel. When the layer comes into contact with seawater, the salt crystals dissolve rapidly, forming numerous microchannels and weak points within the gel matrix. Combined with the pre-designed pore structure of the fiber mesh, this guides rapid water penetration and causes the gel to disintegrate in a controlled and rapid manner along these weakened pathways. This achieves a balance between buffer protection and rapid automatic removal after water immersion, ensuring effective protection during transportation, efficient installation, and no solid residue.

[0017] Preferably, the cured fibers are collected by rollers, rinsed with deionized water for 30 seconds to remove residual calcium chloride on the surface, and then dried in an oven at 40-45 ℃ for 20-30 minutes to obtain dried soluble fibers. The dried soluble fibers are then woven on a weaving device using a plain weave method, with each pair of warp and weft yarns forming a group of two warp yarns and another pair of weft yarns forming a group of two weft yarns. The groups are arranged at a 1 cm interval. During weaving, the weft yarn groups pass between the two warp yarns and are tightened by the reed of the loom. This allows the warp and weft yarns to lock together at the intersection points due to the friction between the fibers and the tightness of the weave, forming a stable fiber mesh with a pore size of 1 cm × 1 cm.

[0018] This invention enhances the mechanical strength of individual fibers by twisting and plying them. Furthermore, it utilizes a plain weave structure with a double warp and double weft configuration, resulting in a tight mechanical interlocking and engagement of the warp and weft threads at their intersections. This structural design, combined with the frictional resistance of the twisted fiber surface and the tightness achieved through the loom tightening process, endows the fiber mesh with excellent dimensional stability and resistance to deformation and unraveling in its dry state. This solves the problem of mesh structure loosening and deformation during subsequent handling, transportation, and pre-installation operations without the use of chemical adhesives, ensuring the structural integrity and reliability of the buffer layer carrier before application.

[0019] Preferably, in step 1), when preparing the artificial algal reef, a one-time molding surface enrichment process is used to concentrate the active adhesion promoter on the surface area of ​​the artificial algal reef. Specifically, this includes the following steps: 8.1) A layer of interface adhesive with a thickness of 1-2 mm is uniformly sprayed onto all inner wall surfaces of the artificial algal reef mold. The adhesive is prepared by mixing water-based epoxy resin and cement in a mass ratio of 1:1; 8.2) On the uncured adhesive surface, the active adhesion promoter dry powder is uniformly sprayed onto the inner wall of the mold using an air pressure spray gun. The spraying density is controlled at 800-1000 g / m², forming a pre-placed promoter layer; 8.3) Before the pre-placed promoter layer cures, the main concrete of the artificial algal reef is poured into the mold and fully vibrated. Under the vibration, the concrete and the pre-placed promoter layer are in full contact; 8.4) Curing is carried out according to conventional processes, and the mold is removed after reaching the demolding strength.

[0020] This invention employs a one-step surface enrichment process, pre-fixing an active adhesion promoter onto the inner wall of the mold before concrete pouring. This allows the promoter to be confined and enriched in the surface area of ​​the artificial algal reef component during subsequent conventional pouring and vibration. This method departs from the traditional approach of directly mixing additives into the entire concrete structure, achieving a precise and high-concentration distribution of active ingredients on the surface layer of the final product. This ensures that algal spores obtain maximum attachment sites and nutrient supply upon contact with the reef surface. Simultaneously, the use of an interfacial binder guarantees a strong bond between the promoter layer and the concrete matrix, effectively preventing premature peeling during subsequent soaking, transportation, and wave erosion. This significantly improves the durability and efficiency of promoter utilization, creating a superior and lasting surface microenvironment for algal attachment and early growth.

[0021] Preferably, the preparation method of the active adhesion promoter includes the following steps: 9.1) mixing seaweed extract and diatomaceous earth at a mass ratio of 1:3, stirring and reacting at 45-55 ℃ for 2-3 h to obtain mixture A; 9.2) drying mixture A at 80-90 ℃ until the water content is less than 5%, and then grinding it into powder with a particle size of 0.1-0.5 mm; 9.3) soaking the powder in a calcium chloride solution with a mass concentration of 2%-3% for 10-15 min, filtering and drying again to obtain the active adhesion promoter.

[0022] This invention prepares a granular active adhesion promoter by loading seaweed extract onto porous diatomaceous earth with a high specific surface area, followed by drying, grinding, and treatment with calcium chloride solution. The promoter's porous structure effectively adsorbs and slowly releases nutrients from the seaweed extract, providing a continuous nutrient supply for seaweed spores. Simultaneously, its rough surface microstructure significantly increases the effective adhesion area and sites on the artificial algal reef concrete surface, improving the physical properties of the matrix. When the promoter is enriched on the surface of the algal reef using the process of this invention, it can continuously and stably create a nutrient-rich microenvironment with a physical structure more conducive to colonization at the spore attachment interface in seawater contact, thereby specifically solving the problem that the chemical properties of the concrete surface are unfavorable for initial spore attachment and germination, effectively improving the efficiency of the pre-attachment stage.

[0023] Preferably, in step 2), the growth of seaweed to a length of 1-15 cm is carried out in a controlled tidal simulation tank system, specifically including: illumination control: using a full-spectrum LED light source to simulate the daytime cycle of the target island area, with an illumination intensity of 300-800 μmol photons / m². -2 s -1 Within the range, a sinusoidal fluctuation is performed with a 4-hour cycle. The light and dark periods are set according to the actual day-night ratio of the target area. Hydrological control: A semi-diurnal tidal cycle with a complete tidal cycle of 12 hours is simulated by a program-controlled water flow pump. In each cycle, the water flow velocity increases linearly from 5 cm / s to 25 cm / s in the first 6 hours to simulate the rising tide. In the following 6 hours, the water flow velocity decreases linearly from 25 cm / s to 5 cm / s to simulate the falling tide. Nutrient control: Nitrogen and phosphorus nutrients are added to the tank at regular intervals every day to maintain the nitrate concentration in the tank at 10-15 μmol / L and the phosphate concentration at 1-2 μmol / L. Growth monitoring: The average length of algae on the surface of the artificial reef is monitored regularly. When the average length of algae reaches 8 cm, it is determined that it has reached the transplantable standard, the simulated cultivation is stopped, and preparations for transportation are made.

[0024] This invention utilizes a water tank cultivation system that precisely simulates the real environment of a target island region to systematically acclimate seaweed larvae attached to artificial algal reefs. The system dynamically simulates various key environmental factors, including periodically varying light intensity, semi-diurnal tidal fluctuations in water flow velocity, and maintaining nutrient concentrations within specific ranges. Seaweed grown in this controlled yet highly simulated dynamic environment allows its physiological state and morphological structure (such as the development of rhizoids and the mechanical strength of the thallus) to adapt in advance to the rhythmic changes and hydraulic stresses of the future marine environment. This proactive environmental acclimatization process effectively reduces the severe environmental stress experienced when seaweed is directly transplanted from a stable laboratory environment to an open, turbulent sea area, thereby significantly improving the survival rate, attachment stability, and adaptability to natural tidal and wave environments of the transplanted seaweed larvae, laying a solid biological foundation for the successful and rapid establishment of seaweed farms.

[0025] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0026] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0027] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0028] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0029] This invention provides a method for ecological restoration of seaweed farms on islands based on artificial algal reefs, comprising the following steps: 1) preparing artificial algal reefs, wherein the artificial algal reefs are constructed of reinforced concrete, have a rectangular cross-section, and a hollow internal structure. At least one outer surface of the artificial algal reef has several holes, and the outer surface of the artificial algal reef is provided with connecting lugs for inter-reef connection. The bottom of the artificial algal reef is provided with mounting lugs with through holes; 2) placing the artificial algal reefs in a spore attachment tank in a nursery. The spore attachment tank contains seaweed propagules, allowing the spores released by the seaweed propagules to attach to the surface and inner wall of the hollow cavity of the artificial algal reef, and allowing the seaweed to grow to a length of 1-15 cm. cm; 3) Transport the pre-attached artificial reefs to the target island area by boat; 4) Install the artificial reefs in a chain during low tide to complete the ecological restoration of the seaweed beds on the island; The chain installation of artificial reefs specifically includes: 4.1) Place the first artificial reef in the predetermined position, with the outer facade with holes perpendicular to the main wave direction, and drill anchor holes in the natural reef by drilling through the through holes of the mounting ear plates; 4.2) Insert the expansion bolts into the anchor holes, and tighten the first nut to lock the expansion sleeve of the bolt into the hole wall, and then connect the second nut to the expansion bolt to press. 4.3) Install the second artificial reef and align its connecting ear plate with the connecting ear plate of the first artificial reef. The outer facade of the second artificial reef is also perpendicular to the main wave direction. Repeat the drilling of anchor bolt holes in step 4.1) and the expansion bolt fixing process in step 4.2) to complete the anchoring of the second artificial reef. 4.4) Use connecting bolts to pass through the through holes of the connecting ear plates of the two artificial reefs and screw in nuts to connect the two adjacent artificial reefs laterally. 4.5) Repeat steps 4.3) and 4.4) to install and connect the subsequent artificial reefs in sequence to form a laterally interlocked artificial reef group.

[0030] In existing technologies, the ecological restoration of seaweed farms on islands often faces the dilemma of inefficiency in directly relying on natural reef bases, or the vulnerability of deployed, unattached, single artificial reefs to wave erosion and displacement. Using large, monolithic prefabricated components to improve stability presents challenges such as difficulties in offshore hoisting and positioning, and high construction risks.

[0031] The specific implementation of this invention is as follows: First, according to design requirements, a single artificial algal reef component is prepared by casting reinforced concrete. The component has a rectangular cross-section and an internal hollow structure to reduce weight, such as a hollow cylindrical structure. Several holes are evenly distributed on at least one outer surface of the component. An outwardly protruding connecting lug is prefabricated on the outer surface of the component, with through holes on the lug. An installation lug with through holes is fixedly installed at the bottom of the component. After curing and reaching the required strength, the prepared artificial algal reef component is transferred to a land-based nursery. It is placed in a large spore attachment tank filled with natural seawater. Mature algae (such as Sargassum fusiforme and Sargassum horneri) collected from the target sea area are pre-placed in the spore attachment tank as propagation bodies. Under suitable light and water flow conditions, the propagation bodies release spores, which gradually attach to all exposed surfaces of the artificial algal reef, including the outer surface, the inner walls of the holes, and the inner walls of the hollow cavities. By controlling the tank environment, the attached algal spores germinate and grow until the algae reach several centimeters in length. Then, using transport vessels, the pre-attached artificial reef components, with the algal larvae reaching the required length, are transported to the waters near the target island. Offshore installation is then carried out during low tide when the waves are relatively calm. During installation, the first artificial reef is first hoisted onto a pre-selected natural reef base and its orientation is adjusted so that the outer facade with the holes is perpendicular to the main wave direction of the area. Anchor bolt holes are drilled in the natural reef using underwater drilling tools through the through holes in the mounting lugs. Next, expansion bolts are inserted, the first nut is tightened to secure the expansion sleeve within the hole, and the second nut is tightened to press the mounting lugs, thus completing the independent anchoring of the first artificial reef. Then, the second artificial reef is hoisted, its connecting lugs aligned precisely with those of the first reef, and its outer facade is similarly adjusted to be perpendicular to the main wave direction. The steps of drilling anchor bolt holes and installing expansion bolts are repeated to complete the independent anchoring of the second artificial reef. Subsequently, corrosion-resistant connecting bolts are passed sequentially through the aligned connecting lugs on two adjacent algal reefs, and nuts are screwed into both ends for tightening, thus achieving a rigid lateral connection between the two algal reefs. Following this method, subsequent artificial algal reefs are installed, anchored, and connected sequentially, ultimately forming a row of horizontally interlocked integral structures on the seabed. This method, through a sequential operation of independent anchoring followed by lateral connection, ensures the initial stability of each unit and the overall wave resistance of the interlocking group. It directly establishes biological populations using pre-grown algal larvae and employs medium-sized modular components for on-site assembly, effectively overcoming the construction and ecological bottlenecks faced by traditional methods.

[0032] Another technical solution also includes the pretreatment of artificial algal reefs. The specific pretreatment process is as follows: the prepared artificial algal reefs are soaked in seawater rich in organic matter for pretreatment for 3-7 days. During the pretreatment, the water in the pretreatment tank is kept circulating to promote the formation of biofilms on the surface of the artificial algal reefs and the inner wall of the hollow cavities. Then, the placement operation in step 2) is carried out to allow algal spores to attach to the biofilm.

[0033] In existing technologies, to promote seaweed attachment, newly prepared artificial algal reefs are often placed directly into spore attachment tanks containing spores. However, clean concrete surfaces are often unfavorable for initial spore colonization, resulting in unsatisfactory attachment rates and slow early growth, thus prolonging the seedling cultivation period.

[0034] This invention adds a crucial pretreatment step before the attachment of seaweed spores. First, a special culture medium for pretreatment needs to be prepared. Specifically, dominant large seaweeds, such as the common Sargassum, are collected from the target island's waters. After washing to remove attached mud and debris, they are crushed into small particles using a pulverizer. These seaweed particles are mixed with natural seawater in a certain proportion and soaked at room temperature for a period of time, with periodic stirring to promote the dissolution of contents. After soaking, the extract is obtained by filtration, resulting in a seaweed extract rich in algal nutrients. On the other hand, organic-rich surface sediments are collected from the intertidal mudflats of the target area. These are mixed with natural seawater and thoroughly stirred. After sufficient time for settling of coarse particles, the supernatant is filtered again to obtain an extract rich in microorganisms and dissolved organic matter. Finally, the seaweed extract and the organic matter extract are mixed in a predetermined proportion and diluted with natural seawater to prepare the organic-rich seawater for pretreatment. Subsequently, the artificial reef components, after being poured, cured, and with clean surfaces, are completely submerged in a large pretreatment tank filled with nutrient solution. The water in the tank is kept in a circulating state to simulate gentle wave action. In this environment, nutrients and microorganisms (including bacteria and microalgae) in the nutrient solution gradually attach, grow, and metabolize on all submerged surfaces of the artificial reef, including the complex pores and hollow cavities. After several days of cultivation, a visible, slippery natural biofilm is formed. This biofilm successfully alters the microscopic physicochemical properties of the concrete surface. After pretreatment, the artificial reef components are then transferred to a spore attachment tank. Here, the biofilm, acting as a more hydrophilic and nutrient-rich active substrate, significantly improves the attachment effect of algal spores.

[0035] In another technical solution, the method for preparing the organic-rich seawater is as follows: Preparation of seaweed extract: Collect local dominant large seaweed, wash and crush it into particles with a diameter of 2-5 mm. Mix the seaweed particles with natural seawater at a mass ratio of 1:10-1:15, soak at room temperature for 48-72 hours, stirring every 8-12 hours. After soaking, filter to remove solid residue to obtain seaweed extract. Preparation of organic matter leachate: Collect surface sediments from natural intertidal mudflats or shellfish farming areas, mix with natural seawater at a volume ratio of 1:5-1:8, stir evenly, and let stand for 24-36 hours. Take the supernatant and filter it through a 100-200 mesh sieve to obtain organic matter leachate. Mix the prepared seaweed extract with the prepared organic matter leachate at a volume ratio of 1:1-2:1, and then add 1-2 times the total volume of natural seawater to dilute the mixture, thus obtaining the organic-rich seawater.

[0036] The organic-rich seawater used in this invention for soaking artificial algal reefs is obtained through a natural-process-mimicking preparation method. Specifically, the preparation of seaweed extract begins. Workers collect dominant, thriving large algae species, such as Sargassum or Sargassum fusiforme, from the surrounding waters of the target island for ecological restoration. The collected seaweed is thoroughly washed to remove surface sediment, small animals, and other impurities. Then, using specialized pulverizing equipment, the washed seaweed is processed into uniformly sized fine particles with a particle size of 2-5 mm. These seaweed particles are then added to a large soaking tank at a predetermined ratio of 1:10 with natural seawater from the same area and extracted at room temperature for 60 hours. During extraction, gentle stirring is performed every 10 hours to promote the release of nutrients from the seaweed cells. After extraction, all solid residues are removed through a multi-layer filtration system, yielding a clear seaweed extract rich in seaweed-derived polysaccharides, proteins, vitamins, and natural growth substances. Simultaneously, the preparation of the organic matter leachate is carried out in parallel. Staff traveled to the intertidal mudflats or adjacent shellfish farming areas in the target region to collect surface sediment samples that were dark in color and rich in organic matter. This sediment was mixed with natural seawater in a separate container in a specific ratio and vigorously stirred to fully disperse it into a suspension. The suspension was then allowed to stand for a sufficient period, such as 30 hours, to allow coarser sand and inorganic particles to settle. The upper layer of liquid was then filtered again through a fine-mesh sieve to obtain an organic matter leachate containing abundant dissolved organic matter, humus, and native microbial communities. Finally, the prepared seaweed extract and organic matter leachate were transferred to a mixing tank and mixed at a 1:1 volume ratio. Then, an equal volume of natural seawater was added for dilution, adjusting the concentration to a suitable level for soaking the algal reef, thus obtaining the final pretreated culture medium. The culture medium prepared using this method has components derived from and adapted to the target ecosystem, enabling more effective guidance for the formation of a stable and fully functional biofilm.

[0037] In another technical solution, during the pretreatment process, intermittent turbulent flow control is implemented for the water circulation in the pretreatment tank. Specifically, a program-controlled circulating water pump is used, with a cycle of 2-4 hours. In each cycle, the water flow velocity is increased to 15-25 cm / s to form a turbulent state for the first 10-15 minutes, and then the water flow velocity is reduced to 5-8 cm / s to maintain a horizontal state until the end of the cycle. The flow velocity in the turbulent state is at least 3 times that in the horizontal state.

[0038] In existing technologies, a constant flow rate is typically used to circulate water in the pretreatment tank. This method makes it difficult to ensure that nutrients and microorganisms are evenly delivered to all surfaces of the artificial reef, especially the internal pores and cavities. This can easily lead to uneven biofilm growth and affect the overall quality of subsequent spore attachment.

[0039] This invention employs a dynamic water flow management mode. During the pretreatment stage, in which the artificial algal reef is immersed in organic-rich seawater, a pretreatment tank is connected to a circulating water pump system managed by a programmable logic controller (PLC). This system operates on a fixed cycle length, for example, 3 hours. At the beginning of each cycle, the controller instructs the pumps to significantly increase the outlet flow rate for a short period, such as 12 hours, bringing the main flow velocity within the pretreatment tank to a high turbulent state. This strong turbulence effectively penetrates the pores of the artificial algal reef, entering its hollow cavities, disturbing the static water boundary layer on each surface, and promoting full contact between the microorganisms and nutrients in the culture medium and the entire submerged surface. Subsequently, for most of the remaining time in the cycle, the controller reduces the pump flow rate to a lower and more stable state, creating a gentle advection. This advection environment provides stable growth conditions for the microorganisms already attached to the surface, allowing them to colonize and begin forming a biofilm. This alternating turbulent and advection cycle continues automatically throughout the pretreatment period. In this way, the periodic changes in hydrodynamic conditions take into account both the uniformity of material transport and the stability of microbial growth, thereby helping to form a biofilm substrate with more uniform thickness and density on all surfaces of the artificial algal reef, including its complex internal structure, laying a good foundation for the attachment of algal spores in the next stage.

[0040] In another technical solution, during the transportation process in step 3), the pre-attached artificial algal reefs are fixed in layers on the ship-borne transport frame, and a buffer isolation layer made of sodium alginate-based hydrogel is set between the contact surfaces of adjacent artificial algal reefs. The thickness of the buffer isolation layer is 2-5 cm, and its surface is kept moist by an atomization system throughout the transportation process.

[0041] In existing technologies, artificial algal reefs with attached algal larvae are usually directly stacked or simply fixed with ropes during ship transportation. Collisions and friction between the reefs are inevitable, causing a large number of fragile larvae to fall off. At the same time, the salt spray and dry air brought by wind and waves during the sea voyage can also cause the larvae to lose water and be damaged, seriously affecting their survival status before transplantation.

[0042] After the artificial reefs have completed pretreatment and spore attachment cultivation, specialized transport protection measures are required before loading them onto ships for transport to the target sea area. Specifically, a sturdy, multi-layered steel frame is first installed on the transport ship's deck as a transport rack. The height of each frame layer is slightly greater than the total thickness of the artificial reef components and the buffer layer. A crucial step is to pre-lay a specially designed buffer pad on all surfaces that may come into contact with adjacent reefs or the frame before hoisting each artificial reef to its designated position on the transport rack. This buffer pad is made of sodium alginate-based hydrogel material, which is flexible and water-retaining, and can be up to 3 cm thick, sufficient to absorb the expected swaying and compressive energy. When placing the artificial reefs, ensure that the buffer pad completely covers the contact area. When multiple artificial reefs are placed on a single frame, their lateral contact is also separated by pre-installed vertical buffer pads. After all reefs are in place, they are secured to the transport rack with adjustable straps to restrict significant movement. Throughout the voyage, a misting system connected to the freshwater tank is periodically activated, spraying fine water mist into the air and onto the surface of the cushioning pads in the transport area. This maintains a locally high-humidity microenvironment, effectively preventing the algae larvae from dehydrating due to prolonged exposure to dry air. When the transport ship arrives at the target sea area for hoisting operations, the cushioning pads, hoisted along with the artificial reef, rapidly absorb moisture and begin to dissolve upon contact with seawater. They typically dissipate completely into the sea within a short time, requiring no manual removal. This protects the larvae and avoids adding extra steps to the underwater installation operation or leaving behind solid waste.

[0043] In another technical solution, the preparation method of the buffer isolation layer is as follows: 6.1) Sodium alginate and starch are dry-mixed at a mass ratio of 3:1 to obtain a mixed dry material; then, the mixed dry material is dissolved in water, and the mass-volume ratio of the mixed dry material to water is 6%-8%. The mixture is stirred at 200-300 rpm for 60-90 min under a water bath condition of 45-55 ℃ to obtain a spinning solution; subsequently, the spinning solution is injected into a calcium chloride aqueous solution with a mass concentration of 4%-5% using a wet spinning process to solidify and form fibers, which are then woven into a mesh with a pore size of 1 cm × 1 cm. After drying, a soluble fiber mesh is obtained; 6.2) Sodium alginate is dissolved in natural seawater at a mass-volume ratio of 4%-6%, and the solution is continuously stirred to obtain a functionalized gel solution; 6.3) 0.5%-1% of the total mass of sea salt crystals is added to the gel solution prepared in step 6.2) to obtain a sea salt gel solution; wherein the particle size range of the sea salt crystals is 0.5-2 mm. The particles are graded according to size, with 0.5-1 mm particles accounting for 60%-70% and 1-2 mm particles accounting for 30%-40%; 6.4) Soluble fiber mesh is placed in a mold, and then sea salt gel solution is injected. Subsequently, cross-linking and curing are carried out by spraying a 2.5%-3% calcium chloride sea water solution. The spraying amount is 0.05-0.08 ml per square centimeter of gel surface, and the cross-linking reaction time is 90-120 s. Finally, a buffer isolation layer with a thickness of 2-3 cm and an internal fiber mesh is formed.

[0044] In preparing the buffer layer, this invention first requires the fabrication of its internal support structure. Sodium alginate powder and food-grade starch are mixed uniformly in a dry state according to a specified ratio. This dry mixture is then added to a certain amount of warm water and stirred continuously to prepare a spinning solution with a specific viscosity. Subsequently, the spinning solution is extruded into a calcium chloride aqueous solution using a wet spinning device. The calcium ions in the solution cause the sodium alginate to instantly cross-link and solidify into continuous gel fibers. These fibers are collected, briefly washed with deionized water to remove excess calcium salts from the surface, and then dried at a low temperature to obtain soluble fibers with a certain strength. Next, these fibers are woven into a uniform mesh fabric using a plain weave machine, serving as the skeleton of the buffer layer. In addition, a functional gel matrix needs to be prepared. Sodium alginate is dissolved in natural seawater and stirred until completely dissolved to form a uniform and transparent gel solution. Pre-sieved sea salt crystals of different particle sizes are then added to this gel solution and stirred until homogeneous. The composite molding process then proceeds: the woven fiber mesh is laid flat at the bottom of the mold, and a gel solution mixed with salt grains is poured onto the mesh until it is completely submerged and reaches the predetermined thickness. Finally, a low-concentration calcium chloride seawater solution is uniformly sprayed onto the gel surface to initiate a cross-linking and curing reaction. After the reaction, the gel completely solidifies and bonds tightly with the internal fiber mesh, forming a complete composite buffer layer of the predetermined thickness. This layer is flexible and supportive in its dry state, and the internal sea salt grains and fiber mesh structure together ensure that it can rapidly and controllably disintegrate upon contact with seawater.

[0045] In another technical solution, the cured fibers are collected by rollers, rinsed with deionized water for 30 seconds to remove residual calcium chloride on the surface, and then dried in an oven at 40-45 ℃ for 20-30 minutes to obtain dried soluble fibers. The dried soluble fibers are then used as warp and weft threads in a plain weave method and woven at 1 cm intervals on a weave device. Specifically, each pair of warp threads forms a group, and each pair of weft threads forms a group, with each group arranged at a 1 cm interval. During weaving, the weft threads pass between the two warp threads and are tightened by the reed of the loom. The warp and weft threads are locked at the intersection points by the friction between the fibers and the tightness of the weave, forming a stable fiber mesh with a pore size of 1 cm × 1 cm.

[0046] As a specific application of the post-processing of fibers obtained from the aforementioned wet spinning process, the continuous gel fibers collected from the coagulation bath are first wound onto rollers and then guided through a deionized water spray zone to briefly and thoroughly rinse away any residual calcium chloride solution on the fiber surface. Subsequently, the rollers containing the moistened fibers are transferred to a hot air circulating oven for drying at a set suitable temperature. The drying process removes most of the moisture from the fibers, strengthening their mechanical properties and forming dry, flexible, and relatively strong soluble fiber filaments. Next, a weaving process is performed. Multiple such dried fiber filaments are twisted together to enhance the strength of individual strands. On a prepared loom, the twisted fibers are used as warp and weft yarns. A specific plain weave structure is employed: each pair of warp yarns forms a group, closely spaced together, with a fixed, uniform spacing between each group; the weft yarns are also inserted in pairs. During weaving, the weft yarn passes between two warp yarns. After each weft insertion, a certain tension is applied by the reed of the loom, pushing the weft yarn towards the weft end. This double-warp, double-weft weaving method, combined with the friction of the twisted fiber surface and the tight interlacing structure formed by the reed tension, ensures a stable mechanical interlocking of the warp and weft yarns at every intersection point without any chemical bonding. The resulting mesh has uniform mesh size and a stable structure, exhibiting good resistance to deformation and unraveling in a dry state, meeting the mechanical strength requirements of a buffer layer skeleton during subsequent handling, cutting, and laying.

[0047] In another technical solution, during the preparation of the artificial algal reef in step 1), a one-time molding surface enrichment process is used to concentrate the active adhesion promoter on the surface area of ​​the artificial algal reef. Specifically, this includes the following steps: 8.1) A layer of interface adhesive with a thickness of 1-2 mm is uniformly sprayed onto all inner wall surfaces of the artificial algal reef mold. The adhesive is prepared by mixing water-based epoxy resin and cement in a 1:1 mass ratio. 8.2) On the uncured adhesive surface, the active adhesion promoter dry powder is uniformly sprayed onto the inner wall of the mold using an air-pressure spray gun. The spraying density is controlled at 800-1000 g / m², forming a pre-placed promoter layer. 8.3) Before the pre-placed promoter layer cures, the main concrete of the artificial algal reef is poured into the mold and thoroughly vibrated. Under vibration, the concrete and the pre-placed promoter layer are in full contact. 8.4) Curing is carried out according to conventional processes, and the mold is removed after reaching the demolding strength.

[0048] In existing technologies, to improve the biocompatibility of artificial reef surfaces, active additives are typically mixed directly into the entire concrete mixture. While this method is simple, the additives are significantly diluted within the component, resulting in a limited proportion of effective components that are actually exposed on the surface and can directly contact algae spores. Furthermore, the additives tend to be unevenly distributed during pouring and compaction, affecting the stability and cost-effectiveness of their adhesion-promoting effect.

[0049] To overcome the aforementioned problems, this invention employs a molding process designed to precisely concentrate active ingredients on the surface of the artificial algal reef concrete components. The specific implementation is as follows: A thin layer of interface adhesive, composed of water-based epoxy resin and ordinary silicate cement in a specific ratio, is uniformly sprayed onto the clean inner wall of the reef mold using a spray gun. While the adhesive is still wet and uncured, a pre-prepared active adhesion accelerator powder is immediately and uniformly sprayed onto the adhesive coating on the entire inner wall of the mold using another pneumatic powder spraying device, forming a pre-placed accelerator powder layer. Subsequently, before the accelerator layer is disturbed or damaged, the main concrete mix for the artificial algal reef is rapidly poured into the mold. After pouring, thorough vibration compaction is immediately performed. During vibration, the fresh concrete comes into close contact and is compressed against the accelerator powder layer on the inner wall of the mold, ensuring that most of the accelerator particles are firmly embedded in the surface concrete of the component, rather than dispersed into the core. After pouring and vibration, the concrete is cured according to standard concrete curing procedures until sufficient demolding strength is achieved, at which point the mold is removed. At this point, the resulting artificial reef component has a high concentration of active adhesion promoter concentrated in the concrete surface layer of all its outer surfaces (i.e., the areas originally covered by the inner wall of the mold). This process ensures that the promoter is mainly distributed at the key interfaces for spore attachment, thus enabling it to function more efficiently in subsequent use.

[0050] In another technical solution, the preparation method of the active adhesion promoter includes the following steps: 9.1) Mix seaweed extract and diatomaceous earth at a mass ratio of 1:3, stir and react at 45-55 ℃ for 2-3 h to obtain mixture A; 9.2) Dry mixture A at 80-90 ℃ until the water content is less than 5%, and then grind it into powder with a particle size of 0.1-0.5 mm; 9.3) Soak the powder in a calcium chloride solution with a mass concentration of 2%-3% for 10-15 min, filter and dry again to obtain the active adhesion promoter.

[0051] The specific preparation method for the key material used in the aforementioned surface enrichment process, the preparation process of the active adhesion promoter, is as follows: First, a loading reaction is carried out. Seaweed extract obtained during the previous preparation of seaweed extract is mixed with pretreated food-grade diatomaceous earth powder, which has a high specific surface area and porous structure, in a reaction vessel according to a predetermined mass ratio. Under continuous stirring and appropriate heating, the active substances in the seaweed extract are fully impregnated and adsorbed onto the micropores of the diatomaceous earth particles. After loading is complete, the resulting mixture is dried to remove most of the moisture, and then processed into a fine powder with uniform particle size using a grinder. This dried powder is then immersed in a calcium chloride aqueous solution of a certain concentration for a short-term calcification treatment. This process allows components such as sodium alginate on the surface of the powder particles to undergo ion exchange with calcium ions, forming a more stable cross-linked structure. After treatment, the solid powder is separated by filtration and dried again to finally obtain a dry powder of the active adhesion promoter with good flowability. The porous structure of diatomaceous earth within these promoter particles locks in the nutrients from seaweed, allowing them to be released slowly. The rough microstructure and calcified structure of the particles themselves enable them to be firmly embedded in the concrete surface through the aforementioned one-time molding surface enrichment process. This provides a long-term and stable physical anchor and nutritional support for the attachment and early growth of seaweed spores after the artificial algal reef is put into use.

[0052] In another technical solution, in step 2), the growth of seaweed to a length of 1-15 cm is carried out in a controlled tidal simulation tank system, that is, simulating tides in a spore attachment tank. Specifically, this includes: light control: using a full-spectrum LED light source to simulate the photoperiod of the target island area, with a light intensity of 300-800 μmol photons / m². -2 s -1 Within the range, a sinusoidal fluctuation is performed with a 4-hour cycle. The light and dark periods are set according to the actual day-night ratio of the target area. Hydrological control: A semi-diurnal tidal cycle with a complete tidal cycle of 12 hours is simulated by a program-controlled water pump. In each cycle, the water flow velocity increases linearly from 5 cm / s to 25 cm / s in the first 6 hours to simulate the rising tide. In the following 6 hours, the water flow velocity decreases linearly from 25 cm / s to 5 cm / s to simulate the falling tide. Nutrient control: Nitrogen and phosphorus nutrients are added to the spore attachment tank daily to maintain the nitrate concentration in the tank at 10-15 μmol / L and the phosphate concentration at 1-2 μmol / L. Growth monitoring: The average length of algae on the surface of the artificial reef is monitored regularly. When the average length of algae reaches 8 cm, it is determined that it has reached the transplantable standard, the simulated cultivation is stopped, and preparations for transportation are made.

[0053] In existing technologies, seaweed larvae are often cultivated in spore attachment tanks with static or constant flow rates. This constant environment differs greatly from the actual dynamic tidal, fluctuating light conditions of the target sea area, resulting in larvae that have not undergone adaptive domestication in terms of morphology and physiology. When transplanted to open sea areas, they are prone to stress responses due to drastic environmental changes, which affects their survival rate and colonization success rate.

[0054] As the final cultivation stage of the aforementioned preparatory work, the growth of seaweed on artificial reefs does not take place in ordinary pools, but rather in a tidal simulation tank system that highly simulates the natural conditions of the target sea area. The core of the system is a large, controllable tank containing artificial reefs that have undergone surface treatment and are awaiting spore attachment and growth. Firstly, regarding lighting control, a programmable full-spectrum LED array is installed above the tank, with a emission spectrum close to natural sunlight. The control system sets the precise daily light and dark durations based on the target island's actual annual sunshine data. Furthermore, the light intensity is not constant, but fluctuates smoothly within a set range, with a period of several hours, simulating light intensity fluctuations caused by cloud cover changes under natural conditions. Secondly, for hydrological control, a computer-controlled variable-frequency pump simulates the semi-diurnal tide pattern. Within a complete simulated tidal cycle, the water flow velocity starts from a low value, linearly increases to a peak value within several hours, simulating the high tide process; then linearly decreases to the initial value within the same time frame, simulating the low tide process. This continuous day-and-night circulation ensures a constant, regularly changing bidirectional water flow within the tank. Furthermore, nutrient control is achieved through an automatic dripping system, which replenishes the circulating tank daily with appropriate amounts of nitrate and phosphate stock solutions. Online monitoring and periodic sampling analysis maintain the nutrient concentration in the water within a low range close to the natural levels of the target marine area, meeting growth requirements while preventing eutrophication. Throughout the cultivation period, technicians periodically sample the tank to monitor the average length of algal larvae attached to different locations on the algal reef. When monitoring data shows that the average length of the algae consistently reaches the preset transplantation standard, it is determined that the larvae have fully adapted to the simulated dynamic environment, are growing robustly, and cultivation can be stopped, allowing them to proceed to the subsequent processes of removal from the tank, transportation, and installation at sea. This system, through comprehensive simulation of key environmental factors, aims to cultivate more environmentally adaptable algal larvae.

[0055] An application example is the ecological restoration project of a seaweed farm on an island in the South China Sea, where the ecological restoration method based on artificial algal reefs described in this invention was applied. The specific implementation steps include: 1. In a land-based prefabrication yard, 200 individual artificial algal reefs were prepared by casting reinforced concrete. Each algal reef has a rectangular cross-section (2m × 1.5m) and an internal hollow cylindrical structure to reduce weight. Holes with a diameter of approximately 10cm are evenly opened on the two long sides of the algal reef. Steel connecting lugs with through holes are prefabricated on both sides of the algal reef, and mounting lugs with through holes are welded to the bottom. Before casting, a "one-time molding surface enrichment process" is used: after spraying a water-based epoxy resin-cement interface agent onto the inner wall of the mold, an active adhesion promoter powder made of diatomaceous earth and locally produced Sargassum extract is immediately sprayed (spraying density approximately 900 g / m²), followed by pouring the main concrete and vibrating for curing. After demolding, the promoter is firmly enriched on the surface of the algal reef.

[0056] 2. Local Sargassum seaweed was collected, crushed, and then extracted with seawater and filtered to obtain an algal extract. Simultaneously, sediment from nearby intertidal mudflats was collected, mixed with seawater, allowed to settle, and filtered to obtain an organic matter leachate. The two were mixed and diluted at a volume ratio of 1.5:1 to prepare the pretreatment solution. The algal reef was completely submerged in a large pretreatment tank filled with the pretreatment solution. A programmable circulating water pump system was used for intermittent turbulence control in 3-hour cycles: the flow rate was increased to 20 cm / s to create turbulence for the first 12 minutes of each cycle, then decreased to 6 cm / s to maintain a steady flow. Pretreatment was continued for 5 days to promote the formation of a uniform biofilm of microorganisms on all surfaces of the algal reef (including pores and cavities).

[0057] 3. The pretreated algal reefs are then transferred to a tidal simulation cultivation system. This system comprises multiple spore attachment tanks, with 4-6 algal reefs placed in each tank. The system accurately simulates the target island environment: it employs a full-spectrum LED light source, simulating the local real diurnal rhythm (14h light / 10h darkness), with a light intensity of 400-700 μmol photons / m². -2 s -1 Within the simulated dynamic environment, the flow rate exhibited a sinusoidal fluctuation with a 4-hour cycle. A semi-diurnal tide was simulated using a variable-frequency pump, with each cycle lasting 12 hours. The water flow velocity linearly increased from 5 cm / s to 24 cm / s within 6 hours, then linearly decreased back within the same 6-hour period. Nutrients were replenished daily to maintain nitrate concentrations at approximately 12 μmol / L and phosphate concentrations at approximately 1.5 μmol / L. Mature Sargassum fusiforme cells collected from the target sea area were introduced into the tank as propagation media. In this simulated dynamic environment, spores attached and grew for approximately 8 weeks, with regular monitoring throughout. Cultivation was stopped when the average length of the algae reached 8 cm.

[0058] 4. On the ship's multi-layered steel transport frame, a specially designed buffer layer is pre-laid on the contact surfaces of each layer and each algal reef. The buffer layer is made of sodium alginate-based hydrogel composite soluble fiber mesh, internally mixed with graded sea salt crystals, and is approximately 3 cm thick. After the algal reef is in place, it is secured with straps. Throughout the voyage, a misting system sprays water mist periodically to keep the surface of the buffer layer and the air around the algal reef moist.

[0059] 5. After the transport vessel arrives at the target sea area, construction will commence during low tide and when waves are relatively calm. A crane vessel will be used to lift each algal reef onto the pre-surveyed and selected natural bedrock reef platform. During installation, the orientation of the algal reef will be adjusted so that the long side with holes is perpendicular to the main wave direction. Anchor bolt holes will be drilled in the bedrock through the through holes in the mounting lugs, expansion bolts will be inserted and tightened, completing independent anchoring. When installing the second algal reef, its connecting lugs will be aligned with the first. After anchoring, stainless steel connecting bolts will be passed through the through holes in the lugs of both algal reefs and the nuts tightened to achieve a rigid lateral connection. Following this sequence of independent anchoring and lateral interlocking, the algal reefs will be installed and connected one by one, ultimately forming a stable, interlocking artificial algal reef group in an area approximately 100 m long and 5-8 m deep.

[0060] Six months after the project was completed, monitoring showed that the interlocking algal reefs were structurally stable, with no displacement or overturning. The algal reef surface and pores were covered with more than 85% seaweed (mainly Sargassum), with vigorous growth and an average length of more than 40 cm, forming a dense primary seaweed field that attracted various fish and benthic organisms, resulting in significant ecological restoration.

[0061] The comparative example is another area with similar ecological conditions on the same island (as a control area), which uses several traditional practices or practices that do not fully apply the core technology of this invention for comparison.

[0062] Comparative Example 1: One hundred ordinary concrete artificial reefs of similar size were deployed, but without any pretreatment (no biofilm formation, no surface accelerator enrichment). The algal reefs were solid structures with smooth surfaces, featuring only simple grooves and no standardized connecting components. They were directly lowered to the seabed without anchoring, relying on their own weight for stability.

[0063] Comparative Example 2: Another 100 ordinary concrete algal reefs were placed in a static seawater tank, inoculated with the same species of Sargassum propagules, and cultivated for the same period of time under constant light and weak circulating water. During transportation, the algal reefs were simply separated by straw mats, without any systematic moisture retention measures.

[0064] Comparison results: After experiencing several typhoon waves, monitoring in Comparative Example 1 revealed that approximately 30% of the material underwent significant displacement or tumbling, with some being buried in sandy sediments.

[0065] On the surfaces of the algal reefs in Comparative Examples 1 and 2, algal spores were sparsely and unevenly attached, with coverage rates of less than 20% after 6 months. The algae grew slowly and were thin and weak. In particular, on the algal reef of Method B, many larvae had detached or died before transplantation due to collisions and drying during transportation.

[0066] In summary, the control area showed slow seaweed farm recovery, failing to establish a habitat with scale and stable structure. In contrast, the application area, through the systematic method of this invention, effectively overcame multiple challenges related to stability, attachment efficiency, larval survival, and construction safety, achieving rapid, efficient, and stable ecological restoration.

[0067] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A method for ecological restoration of seaweed farms on islands based on artificial algal reefs, characterized in that, Includes the following steps: 1) Prepare artificial algal reefs, which are constructed of reinforced concrete, have a rectangular cross-section, and a hollow internal structure. At least one outer surface of the artificial algal reef has several holes. Connecting lugs for inter-reef connection are provided on the outer surface of the artificial algal reef, and mounting lugs with through holes are provided at the bottom. 2) Place the artificial algal reefs in a spore attachment tank in a nursery. The spore attachment tank contains algal vegetative cells, allowing the spores released by the algal vegetative cells to attach to the surface and inner wall of the hollow cavity of the artificial algal reef, and to allow the algae to grow to a length of 1-15 cm. cm; 3) Transport the pre-attached artificial reefs to the target island area by boat; 4) Install the artificial reefs in a chain during low tide to complete the ecological restoration of the seaweed beds on the island; The chain installation of artificial reefs specifically includes: 4.1) Place the first artificial reef in the predetermined position, with the outer facade with holes perpendicular to the main wave direction, and drill anchor holes in the natural reef by drilling through the through holes of the mounting ear plates; 4.2) Insert the expansion bolts into the anchor holes, and tighten the first nut to lock the expansion sleeve of the bolt into the hole wall, and then connect the second nut to the expansion bolt to tighten it. 4.3) Install the ear plate; 4.4) Place the second artificial reef and align its connecting ear plate with the connecting ear plate of the first artificial reef. The outer facade of the second artificial reef is also perpendicular to the main wave direction. Repeat the drilling of anchor bolt holes in step 4.1) and the expansion bolt fixing process in step 4.2) to complete the anchoring of the second artificial reef; 4.5) Use connecting bolts to pass through the through holes of the connecting ear plates of the two artificial reefs and screw in nuts to connect the two adjacent artificial reefs laterally; 4.6) Repeat steps 4.3) and 4.4) to install and connect the subsequent artificial reefs in sequence to form a laterally interlocked artificial reef group.

2. The method for ecological restoration of seaweed farms on islands based on artificial algal reefs as described in claim 1, characterized in that, It also includes the pretreatment of artificial algal reefs. The specific pretreatment process is as follows: the prepared artificial algal reefs are soaked in seawater rich in organic matter for pretreatment for 3-7 days. During the pretreatment, the water in the pretreatment tank is kept circulating to promote the formation of biofilms on the surface of the artificial algal reefs and the inner wall of the hollow cavities. Then, the placement operation in step 2) is carried out to allow algal spores to attach to the biofilm.

3. The method for ecological restoration of seaweed farms on islands based on artificial algal reefs as described in claim 2, characterized in that, The method for preparing the organic-rich seawater is as follows: Preparation of seaweed extract: Collect local dominant large seaweed, wash and crush it into particles with a diameter of 2-5 mm. Mix the seaweed particles with natural seawater at a mass ratio of 1:10-1:15, and soak at room temperature for 48-72 hours, stirring every 8-12 hours. After soaking, filter to remove solid residue to obtain seaweed extract. Preparation of organic matter leachate: Collect surface sediments from natural intertidal mudflats or shellfish farming areas, mix with natural seawater at a volume ratio of 1:5-1:8, stir evenly, and let stand for 24-36 hours. Take the supernatant and filter it through a 100-200 mesh sieve to obtain organic matter leachate. Mix the prepared seaweed extract with the prepared organic matter leachate at a volume ratio of 1:1-2:1, and then add 1-2 times the total volume of natural seawater to dilute the mixture, thus obtaining the organic-rich seawater.

4. The method for ecological restoration of seaweed farms on islands based on artificial algal reefs as described in claim 2, characterized in that, During the pretreatment process, intermittent turbulent flow control is implemented for the water circulation in the pretreatment tank. Specifically, a program-controlled circulating water pump is used, with a cycle of 2-4 hours. In each cycle, the water flow velocity is increased to 15-25 cm / s to form a turbulent state for the first 10-15 minutes, and then the water flow velocity is reduced to 5-8 cm / s to maintain a horizontal state until the end of the cycle. The flow velocity in the turbulent state is at least 3 times that in the horizontal state.

5. The method for ecological restoration of seaweed farms on islands based on artificial algal reefs as described in claim 1, characterized in that, During the transportation process in step 3), the pre-attached artificial algal reefs are fixed in layers on the ship's transport frame, and a buffer isolation layer made of sodium alginate-based hydrogel is set between the contact surfaces of adjacent artificial algal reefs. The thickness of the buffer isolation layer is 2-5 cm, and its surface is kept moist by an atomization system throughout the transportation process.

6. The method for ecological restoration of seaweed farms on islands based on artificial algal reefs as described in claim 1, characterized in that, The preparation method of the buffer isolation layer is as follows: 6.1) Sodium alginate and starch are dry-mixed at a mass ratio of 3:1 to obtain a mixed dry material; then, the mixed dry material is dissolved in water, the mass-volume ratio of the mixed dry material to water is 6%-8%, and stirred at a speed of 200-300 rpm for 60-90 min under a water bath at 45-55 ℃ to obtain a spinning solution; Subsequently, the spinning solution is injected into a 4%-5% calcium chloride aqueous solution using a wet spinning process to solidify and form fibers, which are then woven into a mesh with a pore size of 1 cm × 1 cm. After drying, a soluble fiber mesh is obtained; 6.2) Sodium alginate is dissolved in natural seawater at a mass-volume ratio of 4%-6%, and the solution is continuously stirred to obtain a functionalized gel solution; 6.3) 0.5%-1% of sea salt crystals are added to the functionalized gel solution prepared in step 6.2) to obtain a sea salt gel solution; wherein the particle size of the sea salt crystals ranges from 0.5-2 mm, and they are used according to particle size classification, with particles of 0.5-1 mm accounting for 60%-70%, 1-2 Particles with a diameter of mm account for 30%-40%; 6.4) Soluble fiber mesh is placed in a mold, and then sea salt gel solution is injected. Subsequently, cross-linking and curing are carried out by spraying a calcium chloride sea water solution with a mass concentration of 2.5%-3%, with a spraying amount of 0.05-0.08 ml per square centimeter of gel surface and a cross-linking reaction time of 90-120 s, finally forming a buffer isolation layer with a thickness of 2-3 cm and an internal composite fiber mesh.

7. The method for ecological restoration of seaweed farms on islands based on artificial algal reefs as described in claim 6, characterized in that, The cured fibers are collected by rollers and rinsed with deionized water for 30 seconds to remove residual calcium chloride on the surface. Then, they are dried in an oven at 40-45 ℃ for 20-30 minutes to obtain dried soluble fibers. The dried soluble fibers are then used as warp and weft threads in a plain weave method and woven at 1 cm intervals on a weave device. Specifically, each pair of warp threads forms a group, and each pair of weft threads forms a group. The groups are arranged at 1 cm intervals. During weaving, the weft threads pass between the two warp threads and are tightened by the reed of the loom. The warp and weft threads are locked at the intersection points by the friction between the fibers and the tightness of the weave, forming a stable fiber mesh with a pore size of 1 cm × 1 cm.

8. The method for ecological restoration of seaweed farms on islands based on artificial algal reefs as described in claim 1, characterized in that, In step 1), when preparing the artificial algal reef, a one-time molding surface enrichment process is used to concentrate the active adhesion promoter on the surface area of ​​the artificial algal reef. Specifically, this includes the following steps: 8.1) A layer of interface adhesive with a thickness of 1-2 mm is uniformly sprayed onto all inner wall surfaces of the artificial algal reef mold. This adhesive is made of water-based epoxy resin and cement in a mass ratio of 1:1; 8.2) On the uncured adhesive surface, the active adhesion promoter dry powder is uniformly sprayed onto the inner wall of the mold using an air pressure spray gun. The spraying density is controlled at 800-1000 g / m², forming a pre-placed promoter layer; 8.3) Before the pre-placed promoter layer cures, the main concrete of the artificial algal reef is poured into the mold and fully vibrated. Under the vibration, the concrete and the pre-placed promoter layer are in full contact; 8.4) Curing is carried out according to conventional processes, and the mold is removed after reaching the demolding strength.

9. The method for ecological restoration of seaweed farms on islands based on artificial algal reefs as described in claim 8, characterized in that, The preparation method of the active adhesion promoter includes the following steps: 9.1) Mix seaweed extract and diatomaceous earth at a mass ratio of 1:3, and stir and react at 45-55 ℃ for 2-3 h to obtain mixture A; 9.2) Dry mixture A at 80-90 ℃ until the water content is less than 5%, and then grind it into powder with a particle size of 0.1-0.5 mm; 9.3) Soak the powder in a calcium chloride solution with a mass concentration of 2%-3% for 10-15 min, filter and dry again to obtain the active adhesion promoter.

10. The method for ecological restoration of seaweed farms on islands based on artificial algal reefs as described in claim 1, characterized in that, In step 2), the seaweed growth to a length of 1-15 cm is carried out in a controlled tidal simulation tank system, specifically including: illumination control: using a full-spectrum LED light source to simulate the daytime cycle of the target island area, with a light intensity of 300-800 μmol / m². -2 s -1 Within the range, a sinusoidal fluctuation is performed with a 4-hour cycle. The light and dark periods are set according to the actual day-night ratio of the target area. Hydrological control: A semi-diurnal tidal cycle with a complete tidal cycle of 12 hours is simulated by a program-controlled water flow pump. In each cycle, the water flow velocity increases linearly from 5 cm / s to 25 cm / s in the first 6 hours to simulate the rising tide. In the following 6 hours, the water flow velocity decreases linearly from 25 cm / s to 5 cm / s to simulate the falling tide. Nutrient control: Nitrogen and phosphorus nutrients are added to the tank at regular intervals every day to maintain the nitrate concentration in the tank at 10-15 μmol / L and the phosphate concentration at 1-2 μmol / L. Growth monitoring: The average length of algae on the surface of the artificial reef is monitored regularly. When the average length of algae reaches 8 cm, it is determined that it has reached the transplantable standard, the simulated cultivation is stopped, and preparations for transportation are made.