Ecological artificial reef

下面为大家整理一篇优秀的paper代写范文- Ecological artificial reef，供大家参考学习，这篇论文讨论了生态型人工鱼礁。近几年，由于环境污染和过度捕捞等原因，渔业资源处于严重衰退的状态，严重影响到渔业的发展。因此，保护近海渔业资源成为目前最重要的任务。而建设人工鱼礁是改造近海渔场的一项根本措施，有利于渔业的可持续发展。人工鱼礁是模仿海洋中天然礁石、为水生生物的栖息、生长、繁育场所而人为设置在水域中的构造物，其目的是改善海域生态环境，营造海洋生物栖息的良好环境，为鱼类等提供繁殖、生长、索饵和庇敌的场所，达到保护、增殖和提高渔获量的目的。

In recent years, due to environmental pollution, overfishing and other reasons, China's fishery resources are in a state of serious decline, which seriously affects the sustainable development of fishery economy. Therefore, the protection of offshore fishery resources has become the most important task. The construction of artificial reef is a fundamental measure to transform the offshore fishery and a centennial plan to benefit future generations. Artificial reef is a structure artificially set in the water for the habitat, growth and breeding place of aquatic organisms, imitating the natural reef in the ocean. Its purpose is to improve the ecological environment of the sea area, create a good environment for Marine organisms to live in, and provide places for fish to reproduce, grow, prey and harbor enemies, so as to protect, multiply and increase the catch.

At present, the bottom artificial reef is widely used in the development of Marine ranching. Due to the limitation of artificial reef and seawater depth, the construction cost and delivery cost of artificial reef in deeper waters have been greatly increased, and even the bottom artificial reef cannot be used. The effect of the bottom reef on the upper waters is also limited. China's current offshore pollution is serious, a large number of development, we need to move deeper into the sea to develop Marine pastures to increase fishing output. The bottom reef is no longer sufficient to meet current needs. The floating reef can be fixed to the deeper sea area by anchor rope, and the functional reef is suspended or floating in the upper sea area. However, the research and application of floating reef are few at present. In this paper, a floating reef which can make full use of various water layers and be released into deeper waters is designed for xiangshan port area. Targeted structures to provide suitable and adequate hiding places for fish, spawning places for parent fish and nursery places for young fish.

Floating fish reef is mainly composed of algal reefs, converter reefs and BaoYuYu reef fish three subject and floating ball, connecting rope, anchor rope, anchor block of the four attachment, three reef monomer according to their respective role position arrangement, algal reef at the top is easy to accept the sun, converter reef in the middle of the implementation of the biggest seawater exchange efficiency, BaoYuYu reef at the bottom for the underlying fish larvae conservation.

The reef can also be extended to suit different depths. Sea areas under the jurisdiction of China's coastline is 18000 kilometers, about 300 square kilometers, is the bohai sea, yellow sea, east China sea, the south China sea, the average sea deep never to hundred meters to nearly kilometers deep, we have a lot of sea to pasture of Marine construction, but deep in the sea from dozens of meters to km on the underlying reefs in the sea is not realistic, role is limited. The floating reef designed in this paper can overcome the disadvantage that the range of action of the bottom reef is limited by its own height, and can be arranged to the water layer where it needs to play a role by means of anchor rope and floating ball.

Bait farms are the most important reason for the formation of fishing grounds, and also the fundamental reason for reefs to collect fish and other aquatic organisms. Therefore, the most direct way to collect fish is to plant aquatic plants on reefs and provide food sources for fish. Algae reefs are placed near the surface because the algae need to photosynthesize to get more sunlight. Many people grow algae on the nylon rope, so this paper also adopts this method, using the larger diameter nylon rope as part of the reef, and planting algae on it. Such a design would provide spawning grounds for Marine organisms that lay their eggs on elongated, strip-shaped structures, while growing algae that would act as cover for spawning areas and provide shade and increase dissolved oxygen in the water.

The seaweed reef is placed at an interval of 3m between the top and bottom with two identical supports. The outer circle of the supports is 2m in diameter, the inner circle is 1.2m in diameter, and the material is 70mm in diameter. Eight or more nylon ropes are connected in the middle, and algae and other aquatic plants are planted on the nylon ropes. The supporting structure with internal and external concentric rings can be fixed with more nylon ropes to increase the number of planting plants and provide more space for aquatic organisms to attach.

Artificial reef can change the current environment of the sea area around the reef area and generate local upwelling. Under the action of ocean current, it will also form back eddy and form a certain hydrostatic area on the back flow surface. The upwelling sends sediments and nutrients from the sea bottom to the upper waters, speeding up the circulation of material and promoting the growth of phytoplankton in the upper layers, thus forming a relatively abundant bait field in the local area. Back vortices also attract some fish. Floating reef is different from bottom reef in that it is suspended in seawater and can be in different water layers. Therefore, it can be designed in a proper shape to send the upper layer seawater to the bottom, and the upper layer seawater with higher temperature, more dissolved oxygen and abundant plankton to the lower water.

The designed variable flow reef is composed of four bell-mouth elbow pipes which have the function of changing the flow of water and reasonably fixed and arranged. Place the small end of each bell-mouth bend at the bottom and the large end at the top, vertically. The big mouth of the four elbow pipes is distributed symmetrically in the center in four directions. Two upper and lower fixing plates are used to fix the big mouth into a certain position, and four fixing rods are used to lock the fixing plate. This distribution allows the flow from different directions to enter the bell-mouth elbow, forming a downward flow and facilitating the exchange of seawater between the upper and lower layers.

There is a fixed ear at the bend and roar of the bell-mouth bend, and a mounting hole is left on the ear to match with the upper fixing plate, and the mounting hole of the upper fixing plate. The outer diameter of the elbow here is equal to the inner diameter of the upper fixing pipe, which can be fitted together. The lower surface of the elbow ear is in contact with the upper surface of the upper fixing plate, which is fixed together through the mounting hole. The upper and lower fixing plates are provided with four fixing holes to install the fixing rod. The fixing rod can lock the upper and lower fixing plates, so that the bend pipe and the fixing plate are fixed without deformation. At the same time, the fixed rod is also the position to fix the inverter reef to the connecting rope, so as to prevent damage of the inverter reef caused by directly connecting other weak parts of the inverter reef with the connecting rope.

Xiangshan port is located in the subtropical monsoon zone in the eastern part of Eurasia. In summer, the waters of xiangshan harbour vary greatly in the presence of elongate, oviposition parents of ogres, ogres of ohnius belengerii, Harpadon nehereus, Saurida elongate and elongate trimono, and Trachypenaeus curvirostris. These species lay eggs and incubate in the waters of xiangshan port, and then leave xiangshan port and migrate to the east China sea. Juveniles are vulnerable to predators and other carnivorous fish in nature, so the reef needs to have a smaller and more variable space to provide them with a conservation area. In addition, young fish have weak swimming ability and poor ability to resist the tide, so the reef should be able to slow down the role of the tide. The reef also needs to have better permeability so that the seawater inside the reef can be well exchanged with the outside, so as to keep the seawater inside the reef clean, with high oxygen content and rich food, which is conducive to the growth of young fish. In general, the fish reef will slow down the flow of water by fixing more circular pipes between the upper and lower fixed plates, and form narrow gaps to restrict the entry of large carnivorous fish and protect young fish.

The upper and lower fixing plate is concentric with the inner circular tube to form a transparent passage under the fish reef, which is conducive to the exchange of seawater and the entry of young fish. Internal circular tube, the circular tube with a diameter of 300 mm, the rest of the circular tube with a diameter of 200 mm, lateral hole, pipe hole between the space of the single circular tube and circular tube space together, installation direction for the circular tube side hole direction in the direction of the radius of the pipe in the fixed plate, improve the permeability of rock body, is conducive to the water of the sea into the reefs inside.

Since the weight of the floating reef is greater than its buoyancy, it needs to increase its buoyancy to be able to suspend stably in sea water. If the sea current velocity in the launching area is large, the floating reef will be subjected to great horizontal water resistance. In order to maintain the basic upward state, the floating reef needs to have residual buoyancy to balance the water resistance. In order to give full play to the function of the reef, it is necessary to have enough anchor blocks to fix the floating ball of the reef.

There are two kinds of anchoring methods for the reef: slow anchoring and tension anchoring. When the reef is completely immersed in sea water, the anchor rope is always in tension state, which is called tension anchoring. Anchor rope and reef height and greater than the depth of water, known as slow anchoring. Due to the high tidal current velocity of xiangshan port, there will be a great flow force when the tensioning anchor is used. To make the reef have a small inclination Angle, a large volume of floating ball and a heavier anchor block are required. Therefore, the reef is anchored by slow anchorage. Concrete block is used as anchor block and a single anchor rope is used to connect the reef body and anchor block. The common empirical ratio of the length of the anchor rope to the height of the reef body and the depth of water is 1.2.

The floating reef designed in this paper combines the upper reef, the middle reef and the lower reef with three different functions. The algal reef is composed of materials with slender shape, which can play the role of growing algae to provide food and spawning place. The reef is made up of four bell-mouth bends that carry water from the upper layers of the reef to the lower layers of the reef. The fish reef is composed of upper and lower cover plates and straight pipes with holes in the middle, which not only has good permeability, but also can create a still water area to provide spawning and conservation places.

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