Seaweed cultivation apparatus and seaweed bed formation method

Abstract

The present invention provides a seaweed cultivation device and a method for forming seaweed beds that enable the attachment and growth of seaweed near seawalls or quays. [Solution] This seaweed growing device 10 comprises at least two rope attachment devices 11, 12 installed and spaced apart from each other on the front Q1 of a seawall or quay wall Q or on the outer surface or ground of a marine / port structure that is in contact with seawater, and a rope 14 that is attached to be stretched between the at least two rope attachment devices and is located in the sea where seaweed can attach, and the rope is supported by the rope attachment devices at a predetermined distance from the front or outer surface.

Description

Technical Field

[0006] , , ,

[0001] The present invention relates to a seaweed growth device for growing seaweed in the vicinity of the front surface of a revetment or a quay wall and the outer surface of a marine or port structure, and a method for forming a seaweed bed.

Background Art

[0002] Amid the efforts towards biodiversity, technologies aiming for symbiosis of organisms on revetments and quay walls have been developed. Most of the coastal areas in the metropolitan regions are formed by vertical revetments and quay walls, creating an environment that is difficult for many organisms and plants living in the intertidal zone to settle. Therefore, by making the revetment have a gentle slope or creating a port structure with a shallow field or a tidal flat, it is expected to expand the habitat for organisms and form a harbor space with high hydrophilicity (see Non-Patent Document 1).

[0003] Patent Document 1 discloses attaching a carrier strip with seedlings, which is formed by winding a seedling thread with pre-attached gametophytes of seaweed in a water tank around a carrier strip of an appropriate thickness such as a rope, to the outer surface of a substantially annular holder that also serves as a fixing means for a construction structure (see FIG. 2).

[0004] Patent Document 2 discloses a method of installing a cultivation rope horizontally in the sea by an anchor, a float, and a mooring rope, and growing the thallus of seaweed integrated with a binding band into an adult on the cultivation rope (see FIG. 4).

[0005] Patent Document 3 discloses attaching a string-like body planted with algae or spores of algae to a concrete structure in a state where it can float in the water area facing the concrete structure, and attaching spores released from the algae planted on the string-like body, or spores released from the algae that have germinated and grown from the spores planted on the string-like body, to the wall surface of the concrete structure (see FIG. 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] [Non-Patent Document 1] "Guidelines for the Development and Maintenance of Bio-Symbiotic Port Structures" Ministry of Land, Infrastructure, Transport and Tourism website: https: / / www.mlit.go.jp / kowan / kowan_tk6_000019.html [Non-Patent Document 2] "Initiatives to Expand the Blue Carbon Ecosystem" Toa Construction Co., Ltd. Website: https: / / www.toa-const.co.jp / company / release / 2022 / 220613.html [Overview of the project] [Problems that the invention aims to solve]

[0008] Conventional seawalls designed for biological coexistence primarily focus on organisms, with few methods aimed at promoting seaweed growth on upright seawalls and quays. Among these, Non-Patent Document 2 proposes installing attachment bases with protruding corners to upright port structures to promote seaweed attachment and growth. However, using such attachment bases requires significant effort for structure formation and attachment to the seawall. Furthermore, upright seawalls limit growth opportunities and sunlight, resulting in reduced seaweed growth. Additionally, if seaweed beds are not present in the surrounding area, or if conditions are unsuitable for seaweed growth due to reduced salinity in summer, seaweed bed formation becomes difficult, limiting suitable locations for seaweed bed formation using J-Blue Credits, etc.

[0009] Patent Document 1 uses a roughly annular holder to which a seedling thread-supported strip is attached to the outer surface, making it unsuitable for growing seaweed in a straight line along seawalls or quays. Patent Document 2 involves setting up a cultivation rope horizontally in the sea using an anchor, float, and mooring rope, but near quays or seawalls, there is a high possibility of contact and wear due to the effects of tides and waves, making it unsuitable for growing seaweed at a predetermined distance from the wall surface near seawalls or quays. Furthermore, it is time-consuming as the cultivated seaweed seedlings must be attached to the rope with cable ties. Patent Document 3 involves attaching a string-like body to a concrete structure and allowing spores released from algae planted on the string-like body, or spores released from algae that have germinated and grown from spores planted on the string-like body, to adhere to the wall surface of the concrete structure. It does not allow for the growth of seaweed at a predetermined distance from the wall surface.

[0010] In view of the problems of the prior art described above, the present invention aims to provide a seaweed cultivation device and a method for forming a seaweed bed that enable the attachment and growth of seaweed near the front of seawalls, quays, or the outer surface of marine and port structures that come into contact with seawater. [Means for solving the problem]

[0011] A seaweed cultivation apparatus for achieving the above objective comprises at least two rope attachment devices installed on the front of a seawall or quay, or on the outer surface or ground of a marine or port structure that is in contact with seawater, and spaced apart from each other, and a rope attached so as to be stretched between the at least two rope attachment devices and located in the sea, allowing seaweed to attach and grow, wherein the rope is supported by the rope attachment devices at a predetermined distance from the front or outer surface.

[0012] This seaweed cultivation device allows for the attachment and growth of seaweed near seawalls, quays, and marine / port structures. By stretching a rope between at least two rope attachment devices installed on the front of a seawall or quay, or on the outer surface of a marine / port structure that is in contact with seawater, or on the ground, the rope is stably supported near the front or outer surface. This ensures that seaweed can reliably attach to the rope and grow in the vicinity of the seawall, quay, or marine / port structure, forming a seaweed bed. Furthermore, because the rope is installed at a distance from the front or outer surface, the seaweed attached to the rope can avoid the shaded areas caused by the quay or seawall, and a wider growth area for the seaweed can be secured.

[0013] In the above-described seaweed cultivation apparatus, it is preferable that the rope attachment device has a fixing portion fixed to the front or outer surface, a protruding portion extending from the fixing portion, and a rope attachment portion provided at the tip of the protruding portion.

[0014] Preferably, the rope attachment portion is supported by the protruding portion and is configured to extend vertically or horizontally with respect to the front or outer surface, and is a base for seaweed to attach to.

[0015] Preferably, the protruding portion is configured to be extendable and retractable in the direction of protrusion. This allows the rope to be adjusted to a position that receives more light from the sea surface.

[0016] Preferably, the protruding portion is configured to be movable in the vertical direction relative to the front or outer surface at the joint with the fixed portion. This allows the rope to be adjusted to a location that receives more light from the sea surface and to an appropriate water depth.

[0017] Preferably, the rope is stretched across the front or outer surface in a horizontal, vertical, or inclined direction.

[0018] It is preferable that multiple ropes are stretched across the surface at different distances from the front or outer surface. This allows seaweed to grow efficiently.

[0019] It is preferable that a plurality of the ropes are respectively stretched in a vertical or horizontal direction away from the front surface or the outer surface. Thereby, seaweed can be efficiently grown.

[0020] It is preferable that annular portions for attaching and detaching the rope to and from the rope attachment portion are provided at both ends of the rope. Thereby, installation and recovery of the rope are facilitated.

[0021] It is preferable that a rope holding device for holding the rope is installed between at least two of the rope attachment devices. Thereby, the deflection of the rope can be reduced

[0022] The rope has at least two floating bodies connected at both ends, and the floating bodies are installed so as to be vertically movable in accordance with the tidal level change with respect to the at least two rope attachment devices. It is preferable that the rope between the floating bodies is continuously positioned at a predetermined water depth from the water surface by the vertical movement of the floating bodies in accordance with the tidal level change. Thereby, the rope can be held at a constant water depth with respect to the water surface regardless of the tidal level change.

[0023] Further, the rope attachment device is composed of a pile-like body, and it is preferable that the pile-like body is installed on the ground at a predetermined distance away from the front surface or the outer surface.

[0024] The front surface or the outer surface is substantially upright. Further, the revetment may be an inclined revetment. It is preferable that the rope attachment device is installed on the wave dissipating block or the covering block installed on the inclined revetment.

[0025] A seaweed bed formation method for achieving the above object is to grow seaweed in the sea at a predetermined distance away from the front surface or the outer surface by installing the above-described seaweed growing device on the front surface, the outer surface or the ground to form a seaweed bed.

[0026] According to this method of forming seaweed beds, ropes are stably supported by rope attachment devices on the front of seawalls or quays, or on the outer surface or ground of marine / port structures that come into contact with seawater, and seaweed is reliably attached to and grows on the ropes, thus enabling the formation of seaweed beds near seawalls, quays, and marine / port structures.

[0027] Another method for forming a seaweed bed to achieve the above objective is a method for forming a seaweed bed by installing the seaweed growth device on the front of the aforementioned sloping seawall and growing seaweed in the sea near the front, The aforementioned sloping revetment is a mixture of steeply sloping and gently sloping surfaces, and a seaweed bed is formed on the gently sloping surface using the seaweed growth device.

[0028] This method of forming seaweed beds allows for longer slopes on gently sloping surfaces, enabling the installation of additional ropes, which in turn increases the seaweed bed area and thus the amount of seaweed.

[0029] Another method for forming a seaweed bed to achieve the above objective is a method for forming a seaweed bed by installing the above-mentioned seaweed growth device on the ground and growing seaweed in the sea near the front, The aforementioned ground consists of modified soil placed on top of the original ground. The ground surface of the aforementioned ground is covered with a stone covering that allows seaweed to attach and grow. When there is an exposed modified soil area adjacent to the stone covering area where the ground surface made of the modified soil is exposed, a rope attachment device to which one end of the rope is attached is installed on the stone covering area, and the rope is placed above the exposed modified soil area between the rope attachment device and another rope attachment device to which the other end of the rope is attached, thereby forming a seaweed bed on the exposed modified soil area.

[0030] According to this method of forming seaweed beds, if there is an exposed modified soil area adjacent to a stone-covered area where seaweed can attach and grow, and where the ground surface made of modified soil is unsuitable for seaweed attachment, a rope attachment device can be installed on the stone-covered area. A rope installed between this rope attachment device and another rope attachment device will be positioned above the exposed modified soil area, and seaweed will grow on this rope, thereby forming a seaweed bed on the exposed modified soil area. The other rope attachment device can be installed on another stone-covered area or the ground. [Effects of the Invention]

[0031] According to the present invention, it is possible to provide a seaweed cultivation device and a method for forming a seaweed bed that enable the attachment and growth of seaweed near seawalls or quays. [Brief explanation of the drawing]

[0032] [Figure 1] Figure 1(a) shows a seaweed cultivation device according to this embodiment installed on the front of an upright quay. Figure 1(a) shows a top view (b) taken from the top in the direction of arrow B, and Figure 1(a) shows a side view (c) taken from the side in the direction of arrow C. [Figure 2] This is a front view similar to Figure 1(a), schematically showing the seaweed cultivation device shown in Figure 1 installed on the front of a vertical quay and the resulting seaweed growth. [Figure 3] This is a side view similar to Figure 1(c), showing an example in which the protruding portion in Figures 1(a) to (c) is configured to be extendable and retractable in the protruding direction. [Figure 4] These are front view (a), top view (b), and side view (c) similar to Figures 1(a) to (c), showing an example in which the protruding portion in Figures 1(a) to (c) is configured to be movable in the vertical direction. [Figure 5] Figure 5(a) shows a different seaweed cultivation device according to this embodiment installed in front of an upright quay. Figure 5(a) shows a top view (b) taken from the top in the direction of arrow BB, and Figure 5(a) shows a side view (c) taken from the side in the direction of arrow CC. [Figure 6] This is a front view similar to Figure 5(a), schematically showing the seaweed cultivation device shown in Figure 5 installed on the front of a vertical quay and the resulting seaweed growth. [Figure 7] This is a top view similar to Figure 5(b), showing a modified example of the seaweed cultivation apparatus shown in Figures 5(a) to 5(c). [Figure 8] The figure shows preferred end shapes of the rope in this embodiment, illustrating an example in which loops are formed at both ends of the rope (a) and an example in which metal or resin floats are attached (b). [Figure 9] Figures 1(a) to 1(c) show a side view (a) and a front view (b) after seaweed growth, illustrating an example of a seaweed cultivation apparatus using the floating rope shown in Figure 8(b). [Figure 10] Figures 1(a) to 1(c) show the relative position of the rope to the water surface at mid-tide (a), the relative position at low tide (b), and the relative position at high tide (c). [Figure 11] Figure 9 shows a front view (a) of the rope relative to the water surface at mid-tide, a front view (b) of the rope relative to the water surface at low tide, and a front view (c) of the rope relative to the water surface at high tide when using a rope with a float. [Figure 12] This is a side view similar to Figure 1(c), showing an example where the rope attachment part of the rope attachment device in Figures 1(a) to 1(c) is constructed from a wooden stake. [Figure 13] Figures 9(a) and 9(b) show an example of a seaweed cultivation device in which the rope attachment device is configured in an L-shape, with a front view (a), a top view (b), and a side view (c). [Figure 14] Figures 13(a) to 13(c) are top views showing an example where two ropes are attached to the floating body. [Figure 15] Figures 13(a) to (c) are top views showing an example in which two ropes with floats are attached to the rope attachment point in a loosely fitted state using a ring-shaped device. [Figure 16] Figures 13(a) to (c) are front views showing an example in which the rope float is configured to be attachable to the rope attachment point from the upper side of the quay wall. [Figure 17] This is a side view showing an example of a rope attachment device constructed from a stake-like structure. [Figure 18]Figures 1(a) to 1(c) are front views showing examples where annular devices for attaching ropes are provided at predetermined intervals in the rope attachment section. [Figure 19] This is a front view showing an example of a configuration similar to Figures 1(a) to 1(c), but with the rope installed in a nearly vertical direction. [Figure 20] Figure 20(a) shows a side cross-sectional view of the seaweed cultivation device according to this embodiment installed on a sloping seawall, Figure 20(a) shows a front view of the seaweed cultivation device installed on numerous wave-dissipating blocks on the sloping seawall, viewed from the direction of arrow b in the same figure, and Figure 20(a)(b) shows a side view of a single wave-dissipating block from the side. [Figure 21] Figures 20(a) and 20(c) show the rope attachment device for the seaweed cultivation apparatus (Figure (a)) and the rope holding device (Figure (b)). [Figure 22] Figure 22(a) shows a side cross-sectional view of the seaweed cultivation device according to this embodiment installed on a gently sloping revetment, Figure 22(a) shows a front view of the seaweed cultivation device installed on numerous covering blocks of the gently sloping revetment as seen from the direction of arrow bb in the same figure, Figure 22(a) shows a side view of a rope attachment device installed on a covering block on the sloping surface of the gently sloping revetment as seen in detail, and Figure 22(d) shows a side view of a rope attachment device installed on a covering block on the flat surface of the gently sloping revetment as seen in detail. [Figure 23] These are side views of the main parts showing examples of rope attachment devices to be installed on the covering blocks in Figures 22(a) to (d), (a) and (b). [Figure 24] This is a side view showing a rope holding device installed on the front of the quay, which is located in the middle of the rope attachment equipment in the seaweed cultivation apparatus shown in Figure 1(a) or Figure 3(a). [Figure 25] The first image shows a side cross-sectional view (a) of the seaweed cultivation device according to this embodiment installed on a mixed-type sloping revetment, and the second image shows a side cross-sectional view (b) of the same seaweed cultivation device installed on a steeply sloping revetment. [Figure 26] This is a side cross-sectional view showing a flat region extending in the z-axis direction (towards the open sea) from the lower end of the inclined surface of a sloping seawall, to which the seaweed cultivation device according to this embodiment can be applied. [Figure 27]Figure 26 shows a schematic top view (a), a side cross-sectional view (b), and a side cross-sectional view (c) illustrating the artificial stone covering and the exposed calcia-modified soil in the flat area near the front of the sloping revetment. [Modes for carrying out the invention]

[0033] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Figure 1 is a front view (a) showing the seaweed cultivation device according to this embodiment installed on the front of a vertical quay, a top view (b) seen from the top of Figure 1(a) in the direction of arrow B, and a side view (c) seen from the side of Figure 1(a) in the direction of arrow C. Figure 2 is a front view similar to Figure 1(a) that schematically shows the seaweed cultivation device of Figure 1 installed on the front of a vertical quay and seaweed growing (however, the illustration of each fixing part 1 in Figure 1 is omitted).

[0034] As shown in Figures 1(a) to 1(c), the seaweed growing device (hereinafter referred to as the seaweed growing device) 10 comprises a plurality of rope attachment devices 11, 12 and a rope 14 to which seaweed can attach, stretched horizontally in the x-axis direction between the rope attachment devices 11, 12, and is installed on the front Q1 of an upright quay Q. The quay Q may be a gravity-type quay or a sheet-pile quay installed in a port or the like.

[0035] Each rope attachment device 11, 12 has a plate-shaped fixing part 1 fixed to the front Q1 of the quay Q, and a rod-shaped protruding part 2 attached to the fixing part 1 and extending in the z-axis direction (towards the open sea), both on the top and bottom. Furthermore, it has a rope attachment part 3 that is supported at the ends of the upper and lower protruding parts 2, 2 and extends in the y-axis direction (vertically). For example, the fixing part 1 can be made from a steel plate, the protruding part 2 from a steel rod, and the rope attachment part 3 from a steel pipe. In addition, each rope attachment device 11, 12 can be assembled on land in advance by welding the fixing part 1 and the protruding part 2 together, and welding the protruding part 2 and the rope attachment part 3 together. The protruding part 2 and the rope attachment part 3 may be made of resin, in which case they may be joined by bolts and nuts or the like.

[0036] Each rope attachment device 11, 12 is fixed by attaching the plate-shaped fixing part 1 to the front Q1 of the quay wall Q using anchor bolts 17 (Figure 1(c)). After installing each rope attachment device 11, 12 on the front Q1 of the quay wall Q, the rope 14 can be attached and fixed by wrapping it around the joint between the protruding part 2 and the rope attachment part 3 and tying it. In Figure 1(a), the rope 14 is installed on top of the rope attachment devices 11, 12, but it may also be installed on the bottom as shown by the dashed line in Figure 1(a), allowing the rope's water depth position to be set according to the water depth suitable for seaweed growth on the rope.

[0037] Furthermore, while various materials can be used as the material for the rope 14 to allow seaweed to attach, hemp, paper, or biodegradable plastic ropes may also be used. Because these materials are biodegradable, even if they are released into the environment, they will not cause problems such as microplastic pollution.

[0038] Furthermore, the distance L (in the z-axis direction) from the front Q1 of the quay wall Q to the rope 14 is preferably about 20 to 100 cm, and can be adjusted by changing the length of the protruding part 2. In addition, the rope attachment parts 3 extending in the y-axis direction of the rope attachment devices 11 and 12 can be used as a substrate for seaweed attachment. Examples of seaweed that can be attached and grown include kelp, wakame, arame, kajime, kurome, akamoku, oobamoku, and the genus Sargassum.

[0039] Furthermore, the width W in the x-axis direction between the rope attachment devices 11 and 12 in Figure 1(a) is preferably set in the range of several meters to several tens of meters. The number of rope attachment devices can be set according to the overall installation width of the seaweed growth device 10 on the front Q1 of the quay wall Q. For example, as shown by the dashed line in Figure 1(b), it is possible to add rope attachment devices 13 similar to rope attachment devices 11 and 12, and ropes 15 on which seaweed can attach between rope attachment devices 12 and 13. In addition, the installation range of the seaweed growth device 10 may be set considering the tidal level fluctuations on the front Q1.

[0040] By installing the seaweed growth apparatus 10 shown in Figures 1(a) to 1(c) in the sea in front of the quay Q (Q1), the rope 14 is stably supported away from the front of the quay Q (Q1). As shown in Figure 2, seaweed can reliably attach and grow on the rope 14 stretched in the x-axis direction and on each rope attachment point 3 installed in the y-axis direction, thereby enabling the growth of seaweed SW in the vicinity of the front of the quay Q (Q1). Furthermore, because the rope 14 is installed away from the front of the quay Q (Q1), the seaweed SW attached to the rope 14 can avoid the shaded area created by the quay Q, and a wider growth area for the seaweed SW can be secured.

[0041] Furthermore, the protruding portion 2 in Figures 1(a) to (c) may be configured to be extendable and retractable in the z-axis direction, as shown in Figure 3. Specifically, the protruding portion 2A in Figure 3 is configured to be extendable and retractable by using steel pipes 2a and 2b of different diameters, inserting the larger diameter steel pipe 2b into the smaller diameter steel pipe 2a fixed to the fixing portion 1, and allowing it to be extended and retracted in the z-axis direction. This allows the rope 14 to be positioned together with the rope attachment portion 3 so that it can receive more light from the sea surface. The position of the steel pipe 2b after extension and retraction adjustment may be fixed using known means such as bolts.

[0042] Furthermore, the protruding portion 2 in Figures 1(a) to (c) may be configured to be movable in the y-axis direction. That is, as shown in Figures 4(a) to (c), the fixed portion 1A is configured as a flat rail extending in the y-axis direction and having an internal gap c, and the rectangular plate-shaped movable portion 1B is slidably inserted into the U-shaped gaps c on both sides. The protruding portion 2 is fixed to the movable portion 1B. The movable portion 1B can move in the y-axis direction together with the protruding portion 2 within the gap c of the fixed portion 1A and can be set to the desired position. This allows the rope 14 to be adjusted together with the protruding portion 2 to a location that receives more light from the sea surface and to a water depth suitable for the seaweed to grow. The movable portion 1B after adjustment may be fixed in place by known means such as bolts.

[0043] Figure 5 shows a front view (a) of another seaweed cultivation device according to this embodiment installed in front of a vertical quay, a top view (b) of Figure 5(a) viewed from the top in the direction of arrow BB, and a side view (c) of Figure 5(a) viewed from the side in the direction of arrow CC. Figure 6 is a front view similar to Figure 5(a) that schematically shows the seaweed cultivation device of Figure 5 installed in front of a vertical quay and seaweed growing (however, the illustration of each fixing part 1 in Figure 5 is omitted).

[0044] The seaweed growing apparatus 20 shown in Figures 5(a) to (c) is configured such that, in addition to the rope attachment devices 11 and 12 shown in Figures 1(a) to (c), another rope attachment device similar to the one shown is installed in the z-axis direction, providing a protruding part 27 and a rope attachment part 28. Multiple ropes are then installed, spaced apart in the y-axis and z-axis directions, each extending in the x-axis direction. Specifically, the rope attachment devices 21 and 22 of the seaweed growing apparatus 20, as shown in Figures 5(a) to (c), have, in addition to each fixing part 1, each protruding part 2, and each rope attachment part 3, a rod-shaped protruding part 27 attached to each rope attachment part 3, and a rope attachment part 28 supported at the ends of the upper and lower protruding parts 27 and extending in the y-axis direction. The protruding part 27 and the rope attachment part 28 may have the same configuration as the protruding part 2 and the rope attachment part 3, and the rope attachment part 28 can be a seaweed attachment substrate, similar to the rope attachment part 3.

[0045] The seaweed cultivation device 20 includes a rope 14 similar to those shown in Figures 1(a) to (c), as well as a rope 24 stretched in the x-axis direction between the rope attachment device 21 and the rope attachment device 22 described above, and is installed in front of the upright quay Q Q, on the front Q1. As shown in Figures 5(a) to (c), the rope 14 is installed at the top on the side closer to the front Q1, and the rope 24 is installed at the bottom on the offshore side further away from the front Q1. By installing multiple rows of ropes 14 and 24 at different water depths in this way, a large variety of seaweed to be grown and a large growing area can be secured.

[0046] Furthermore, although ropes 14 and 24 are installed at different depths in Figures 5(a) to (c), they may also be installed at the same depth. Suitable seaweeds can grow depending on the water depth; for example, brown algae grow at depths of 3 to 10 m, and green algae grow at depths shallower than 3 m. For this reason, the same type of seaweed may be used if the depths of ropes 14 and 24 are the same, or the target type of seaweed may be changed by changing the depths of ropes 14 and 24.

[0047] By installing the seaweed growth apparatus 20 shown in Figures 5(a) to (c) in the sea in front of the quay Q1, the ropes 14 and 24 are stably supported near the front of the quay Q1. As in Figure 2, seaweed SW attaches to the rope 14 and the rope attachment 3 and grows. Furthermore, as shown in Figure 6, seaweed SW attaches to the rope 24 stretched in the x-axis direction and to each rope attachment 28 installed in the y-axis direction. This results in a larger growth area near the front of the quay Q1 than in Figure 2, allowing seaweed SW to grow more efficiently.

[0048] Furthermore, as shown in Figure 6, when seaweed SW grows to about 2-3m on rope 14 installed near the water surface, if a rope is installed vertically below it, the light may be blocked by the seaweed vertically above, and the increased water depth may reduce underwater illumination, potentially negatively impacting seaweed growth. However, by installing the lower rope 24 further away from the front Q1 of the quay wall Q than rope 14, as shown in Figures 5(a)-(c), the negative impact on seaweed growth can be mitigated. In addition, the protrusion length of the lower protrusion 27 in Figures 5(a)-(c) may be made longer than the upper protrusion 27 to allow light to reach the seaweed below and improve its growth. Moreover, if the sunlight conditions for seaweed meet the specified growth conditions, an additional rope may be added at the same water depth as rope 14 and at a distance away from the front Q1 (the same distance as rope 24), and / or at the same water depth as rope 24 and at a distance closer to the front Q1 (the same distance as rope 14). Figure 6 shows an example where mature seaweed SW, such as wakame, hangs downward due to its own weight on the upper rope 14, while mature seaweed SW of Sargassum species, which have air bladders, stand upright due to the buoyancy of the air bubbles and hang upward on the lower rope 24.

[0049] Figure 7 is a top view similar to Figure 5(b) showing a modified example of the seaweed growth apparatus 20 shown in Figures 5(a) to (c). In the example in Figure 7, the rope attachment devices 21, 22 and the additional rope attachment device 23 shown in Figures 5(a) to (c) are positioned offset in the x-axis direction relative to the positions of the rope attachment devices 11, 12, and 13, while remaining approximately parallel to the front surface Q1 of the quay wall Q. With respect to the width W between rope attachment devices 11, 12 and between rope attachment devices 12, 13, and between rope attachment devices 21, 22 and between rope attachment devices 22, 23, rope attachment device 21 is offset from rope attachment device 11 by approximately W / 2, and rope attachment device 22 is offset from rope attachment device 12 by approximately W / 2. The rope 14 between rope attachment devices 11 and 12, and the additional rope 15 between rope attachment devices 12 and 13, are installed at the top on the side closer to the front Q1, while the rope 24 between rope attachment devices 21 and 22, and the additional rope 25 between rope attachment devices 22 and 23, are installed at the bottom on the side further from the front Q1 than ropes 14 and 15. Note that the installation positions of rope attachment devices 21 and 22 relative to the width W between rope attachment devices 11 and 12, and between rope attachment devices 12 and 13, are not limited to W / 2, and may be offset from the W / 2 position.

[0050] Figure 8 shows preferred end shapes of the rope in this embodiment, illustrating an example where loops are formed at both ends of the rope (a) and an example where floats are attached (b). In Figure 8(a), rope 14A has loops 18, 18 formed at both ends of the rope as annular sections corresponding to the outer shapes of the rope attachment section 3 in Figures 1(a) to (c) and the rope attachment section 28 in Figures 5(a) to (c). In Figure 8(b), rope 14B has metal or resin floats 19, 19 attached to both ends of the rope, with the float 19 having an attachment hole 19a at the center, which is an annular section corresponding to the outer shapes of the rope attachment section 3 and the rope attachment section 28. Ropes 14A and 14B can be installed by attaching the loops 18 and floats 19 over the rope attachment sections 3 and 28, and can be removed by pulling them out. This makes it easy to install and retrieve ropes 14A and 14B.

[0051] Figure 9 shows a side view (a) and a front view (b) after seaweed growth, illustrating an example of a seaweed growth apparatus using the floating rope shown in Figure 8(b) in Figures 1(a) to (c). The seaweed growth apparatus 10A in Figures 9(a) and 9(b) uses a rope 14B with floating bodies 19 at both ends, as shown in Figure 8(b), and the mounting holes 19a of the floating bodies 19 are sized to loosely fit into the rope attachment section 3 in a loosely fitted state. When the rope 14B is installed in the x-axis direction in a loosely fitted state to the rope attachment section 3 by the floating bodies 19, the rope 14B is stably supported near the front Q1 of the quay wall Q, and the floating bodies 19 become buoyant and move up and down (y-axis direction) in accordance with the fluctuations in the tide level. Therefore, the rope 14B can be positioned at a specific water depth (for example, the water surface or the optimal water depth for growth) according to the tide level as a floating type. By equipping the rope with a float in this way, the rope's position can be automatically adjusted to a depth suitable for seaweed growth, even in areas with large tidal fluctuations, according to the tide level. The float 19 is not limited to a donut shape in plan view; it may also be a polygon, such as a square. If a float is not required, the rope 14A shown in Figure 8(a) can be used to attach the rope to the attachment section 3. However, in this case, the float 19 will get caught at the position of the protruding section 2, so it is preferable to adjust the installation depth of the rope attachment devices 11 and 12 so that the water depth is suitable for seaweed even at low tide. Furthermore, when installing the rope below the rope attachment section 3, the work can be carried out by a diver.

[0052] Next, the rope position due to tidal fluctuations in the fixed rope structure shown in Figure 1 and the floating rope structure shown in Figure 9 will be explained with reference to Figures 10 and 11. Figure 10 is a front view (a) showing the relative position of the rope to the water surface at the mid-tide, a front view (b) showing the relative position at low tide, and a front view (c) showing the relative position at high tide, as shown in Figures 1(a) to (c). Figure 11 is a front view (a) showing the relative position of the rope to the water surface at the mid-tide, a front view (b) showing the relative position at low tide, and a front view (c) showing the relative position at high tide, as shown when using the floating rope in Figure 9.

[0053] The seaweed cultivation apparatus 10 shown in Figures 1(a) to 1(c) is a fixed rope structure in which rope attachment devices 11 and 12 are fixed to the front Q1 of the quay wall Q, and the rope 14 is attached and fixed approximately horizontally between the rope attachment devices 11 and 12. Therefore, the rope 14 is always in a constant vertical position regardless of the tide level. For example, at the mid-tide level in Figure 10(a), it is at a predetermined depth relative to the water surface; at low tide in Figure 10(b), it is at or near the water surface; and at high tide in Figure 10(c), it is at its maximum depth relative to the water surface. The vertical position of the rope 14 is set so that the rope 14 is not exposed above the water surface at low tide in Figure 10(b).

[0054] The seaweed cultivation device 10A shown in Figures 9(a) and 9(b) is a floating rope structure in which floating bodies 19 at both ends of the rope 14B are loosely fitted to the rope attachment parts 3 of the rope attachment devices 11 and 12, and the rope 14B is stretched in a substantially horizontal direction. As a result, the rope 14B moves in the y-axis direction in accordance with the fluctuations in the tidal level due to the floating bodies 19, and is always at or near the water surface at all tidal levels, including the mid-tide in Figure 11(a), low tide in Figure 11(b), and high tide in Figure 11(c). This allows for efficient cultivation of seaweed SW by utilizing the light-rich water surface or near the water surface, regardless of tidal fluctuations. Maintaining the rope 14B at or near the water surface as shown in Figures 11(a) to 11(c) is preferable when the water depth for seaweed growth is shallow due to relatively high turbidity in the sea area. Furthermore, the floating body 19 can adjust the buoyancy it generates to keep the rope 14B at a suitable depth, not just at or near the water surface. As a result, the rope 14B can always maintain a suitable depth, which can increase the growth rate of seaweed SW.

[0055] Figure 12 is a side view similar to Figure 1(c), showing an example where the rope attachment part of the rope attachment device in Figures 1(a) to (c) is constructed from a wooden stake. The rope attachment part 3 in Figures 1(a) to (c) may be made of metal or resin, but the rope attachment device 13A in Figure 8 has a rope attachment part 3A made of a wooden stake in addition to the fixing part 1 and protruding part 2 similar to those in Figures 1(a) to (c), and the rope attachment part 3A is connected to and supported by the protruding part 2 via an annular stake holder 4. By constructing the rope attachment part 3A from a wooden stake, the CO2 emissions from the material can be reduced compared to rope attachment parts made of metal or resin.

[0056] Furthermore, while the quay Q in Figures 1 and 3 is preferably an unused quay where ships dock or moor, it may also be an active quay in a port where ships dock or moor. In this case, the distance L in the z-axis direction in Figure 1(b) is preferably smaller than the protruding length of the fender attached to the quay Q from the front Q1. Also, if the distance L in Figure 1(b) is larger than the protruding length of the fender, if the frequency of ships docking is low, the rope can be retrieved when docking and reinstalled when leaving the quay. Such retrieval and reinstallation can be easily achieved, for example, by using the ropes 14A and 14B in Figures 8(a) and 8(b). Also, for example, if the rope is located 1m away from the front Q1 of the quay Q and the protruding length of the fender is 30cm, this can be addressed by shortening the protruding length of the protruding part 2 so that the rope is within 30cm of the front Q1 (see Figure 3), thereby bringing it closer to the front of the quay. Furthermore, when the captain of the docking vessel needs to fit between the rope attachment devices 11 and 12, the installed ropes may be loosened to accommodate this.

[0057] Next, another example of a seaweed cultivation device having a floating rope structure as shown in Figures 9(a) and 9(b) will be described. Figure 13 is a front view (a), top view (b), and side view (c) of an example of a seaweed cultivation device in which the rope attachment device of Figures 9(a) and 9(b) is configured in an L shape. The seaweed cultivation device 10B shown in Figures 13(a) to 13(c) is equipped with rope attachment devices 61 and 62 made of rod-shaped bodies configured in an L shape, and has a structure using a rope with a floating body. The rope attachment devices 61 and 62 have rope attachment parts 63 and 63 that extend downward along the y-axis toward the sea, a protruding part 64 that bends at a right angle toward the upper end Q2 of the quay wall Q and extends in the z-axis opposite to the offshore direction, and a fixing part 65A that is fixed to the upper end Q2 at the tip of the protruding part 64, and can be easily constructed from a rod-shaped body such as a steel rod. The fixing part 65A is fixed to the upper end Q2 of the quay wall Q using anchor bolts (not shown) or the like. The floating body 19 of the rope 14B is attached to the rope attachment part 63 from the lower end in a loosely fitted state using the attachment hole 19a, and the rope 14B with the floating body is installed between the rope attachment devices 61 and 62. Therefore, the rope 14B with the floating body remains at or near the water surface even when there are tidal level fluctuations such as low tide and high tide, as in Figures 11(a) to (c). The distance L in the z-axis direction from the front Q1 to the rope 14B (Figure 1(b)) can be adjusted by the length of the protruding part 64. The protruding part 64 may also be configured to be extendable and retractable in the z-axis direction.

[0058] Furthermore, since it is a difficult task to sink the floating body 19 after installing the rope attachment devices 61 and 62 shown in Figures 13(a) to (c) and attach it from the lower end of the rope attachment section 63, it is preferable to attach the floating body 19 by loosely fitting it from the upper end of the rope attachment section 63, using a structure that allows the rope attachment section 63 to be removed and returned to its original connected state at the corner connection between the rope attachment section 63 and the protruding section 64, or to make a notch in a part of the floating body 19 so that the floating body 19 can be passed through the rope attachment section 63 and attached, and then close the notch after the floating body 19 is attached, or to use an annular device 19b that can be opened and closed as shown in Figure 15, which will be described later. Furthermore, as a structure for removing the rope attachment portion 63 and returning it to its original connected state, a hollow cylindrical member is used instead of the rod-shaped rope attachment devices 61 and 62 of the seaweed growth device 10B, a threaded portion is provided on the upper end of the rope attachment portion 63, and the rope attachment portion 63 is screwed into the threaded portion provided on the inner circumference of the protruding portion 64. This allows the floating body 19 to be loosely attached from the upper end of the removed rope attachment portion 63, and then the original connected state can be returned by screwing it in.

[0059] Alternatively, as shown in Figure 14, in Figures 13(a) to (c), a rope 14C may be added and connected to the floating body 19 in addition to rope 14B, resulting in two ropes 14B and 14C.

[0060] Furthermore, as shown in Figure 15, two ropes 14B with floating bodies 19A are installed, and each floating body 19A is connected to the rope attachment section 63 via an annular fitting 19b with a relatively large inner diameter, eliminating the need for attachment holes. Since the annular fitting 19b is attached to the rope attachment section 63 in a loosely fitted state, it becomes a floating rope structure similar to Figures 13(a) to (c). Note that in order to install two ropes 14B with floating bodies 19A, it is necessary to add a rope attachment section 63 (Figure 13(a)) to the rope attachment devices 61 and 62, but in the case of one rope, the configuration may be the same as that of the rope attachment devices in Figures 13(a) to (c).

[0061] Furthermore, the rope attachment device 65 in Figure 16 has a fixing auxiliary part 68 that extends downward along the y-axis toward the sea, a U-shaped part 67 that connects the lower end of the fixing auxiliary part 68 to one end, and a rope attachment part 66 that extends upward along the y-axis from the other end of the U-shaped part 67 and whose upper end is exposed above the water surface even at high tide so that the floating body 19 does not come off. The fixing auxiliary part 68 has an upper end fixing part 69 that extends upward along the y-axis and bends at a right angle in the negative z-axis direction toward the upper end Q2 of the quay wall Q. The fixing auxiliary part 68 is connected at its lower end to the lower end of the rope attachment part 66 via the U-shaped part 67, and the upper end fixing part 69 is fixed to the upper end Q2. With the rope attachment device 65, by providing the fixing auxiliary part 68, the floating body 19 of the rope with floating body 14B can be attached to the rope attachment part 66 from the upper end from the upper side of the quay wall Q. Furthermore, the fixing support portion 68 may be configured as a linearly extending rod-shaped portion omitting the upper end fixing portion 69, with its upper end fixed to the upper part of the front surface Q1 of the quay wall Q. Also, the rope attachment portion 66 and the fixing support portion 68 may be positioned so as to overlap in the z-axis direction, or they may be positioned so as to be aligned in the x-axis direction.

[0062] Furthermore, the rope attachment device 71 in Figure 17 is composed of a single pile-like body, and is fixed by penetrating the seabed ground G at a predetermined distance in the z-axis direction from the front Q1 of the quay wall Q. The floating body 19 of the floating rope 14B can be attached to the rope attachment device 71 from the upper end from the upper side of the quay wall Q. Note that at least two of the rope attachment devices 65 and 71 in Figures 16 and 17 are installed in the x-axis direction, and the floating rope is stretched between them. Also, since the rope attachment device 71 is installed independently of the quay wall Q, the predetermined distance at which it is installed may be longer than the distance L from the front Q1 in Figure 1(b), and in this case as well, it is within the vicinity of the front Q1.

[0063] Furthermore, the rope attachment device 11A in Figure 18 is configured such that, as shown in Figures 1(a) to (c), annular fittings 3d such as D-rings are attached to the rope attachment part 3 at predetermined intervals in the y-axis direction, for example, every 50 cm, and the rope 14 is installed by hooking a hook-shaped part 14d (or a metal part such as a carabiner or cam jam) attached to the end of the rope 14 onto it. Alternatively, the hook-shaped part 14d may be omitted, and the rope 14 may be directly attached by passing it through the annular fitting 3d. This makes it easy to change the water depth position of the rope 14, for example, every 50 cm, and also makes it easy to lay the rope 14 at an angle.

[0064] Furthermore, while the ropes are installed to extend in the x-axis direction in Figures 1(a)-(c) and 5(a)-(c), to accommodate the growth of multiple types of seaweed that prefer different water depths, the ropes 14 may be installed at an angle to the x-axis direction, for example, as shown by the dashed line in Figure 1(a).

[0065] Alternatively, as shown in Figure 19, the rope may be installed so as to extend in the y-axis direction. That is, the seaweed growing device 80 in Figure 19 comprises a plurality of rope attachment devices 81, 82 and a rope 84 to which seaweed can attach, stretched between the rope attachment devices 81, 82 in the y-axis direction, and is installed on the front Q1 of an upright quay wall Q. The rope 84 is located a predetermined distance in the z-axis direction from the front Q1. The rope attachment devices 81, 82 have the same configuration as the rope attachment devices 11, 12 in Figures 1(a) to (c), but are installed vertically so as to extend in the x-axis direction. Multiple ropes 84 can be installed. In addition, each rope attachment part 83 of the rope attachment devices 81, 82 protrudes from the front Q1 and extends in the x-axis direction, becoming a seaweed attachment base that can grow seaweed. Note that the rope attachment devices may have the same configuration as the rope attachment devices 21, 22 in Figures 5(a) to (c), and may be installed so as to extend in the x-axis direction.

[0066] Next, an example of applying the seaweed cultivation device according to this embodiment to a sloping seawall will be described with reference to Figures 20(a) to (c) and 21(a) and (b). Figure 20 is a side cross-sectional view (a) showing the seaweed cultivation device according to this embodiment installed on a sloping seawall, a front view (b) of the seaweed cultivation device installed on numerous wave-dissipating blocks of the sloping seawall in Figure 20(a) as seen from the direction of arrow b in the same figure, and a side view (c) of a single wave-dissipating block in Figures 20(a) and (b) as seen from the side. Figure 21 is a diagram (a) showing the rope attachment device for the seaweed cultivation device in Figures 20(a) to (c) and a diagram (b) showing the rope holding device.

[0067] As shown in Figures 20(a) and (b), the sloping seawall D has numerous concrete wave-dissipating blocks BL installed along the sloping surface 50 from the lower end underwater to the upper end near land in the y-axis and z-axis directions, and over a predetermined distance in the x-axis direction. The seaweed growth device 30 shown in Figures 20(a) to (c) comprises a rope attachment device 31 attached to the wave-dissipating block BL at the left end of Figure 20(b) installed on the sloping surface 50 of the sloping seawall D, a rope attachment device 32 attached to the wave-dissipating block BL at the right end, and a rope 34 stretched between the rope attachment devices 31 and 32 in the x-axis direction. In addition, rope holding devices 33, 33 are attached to the wave-dissipating block BL between the rope attachment devices 31 and 32 to hold the rope 34.

[0068] As shown in Figure 20(a), the inclined revetment D is composed of an inclined surface 50 and a flat surface 51, and the inclination angle θ1 of the inclined surface 50 is, for example, approximately 37° (1:4 / 3) with respect to the horizontal plane. In addition, concrete covering blocks HB are laid on the flat surface 51 that follows the lower end of the inclined surface 50 and on the inclined surface that slopes from the flat surface 51.

[0069] The rope attachment devices 31 and 32, as shown in Figure 21(a), each comprise a rod-shaped projection 31a and a ring-shaped rope attachment portion 31b positioned at its tip, and can be constructed from, for example, a steel rod. The rope attachment device 31 can be fixed by inserting the rod-shaped projection 31a into a fixing hole formed at a predetermined position in the wave-dissipating block BL, as shown by the dashed line in Figure 20(c), and then filling the fixing hole with a filler material. The rope holding device 33 may have the same configuration as the rope attachment device 31, so the rope attachment device 31 can also be used as a rope holding device. The rope 34 can be installed by passing it through the ring-shaped rope attachment portions 31b of the rope holding devices 33, 33, and then tying it, for example, with the ring-shaped rope attachment portions 31b of the rope attachment devices 31 and 32 at both ends.

[0070] Figure 21(b) shows another example of a rope holding device. This rope holding device 35 comprises a rod-shaped projection 35a and a spiral rope holding part 35b located at the tip. The rope 34 can be installed by pushing it from the side into the spiral rope holding part 35b as shown by the dashed line in the figure and moving it towards the center through the spiral space. Therefore, the rope 34 can be passed through the rope holding device 35 after it has been installed using the rope attachment devices 31 and 32 at both ends. The rope holding devices 33 and 35 can hold the rope 34 in an intermediate position and reduce the bending of the rope 34.

[0071] By installing the seaweed growth device 30 shown in Figures 20(a)-(c) and 21(a)(b) on the wave-dissipating block BL installed on the inclined surface 50 of the inclined seawall D, the rope 34 is stably supported in the vicinity of the inclined surface 50, and seaweed can reliably attach to and grow on the rope 34 in the x-axis direction, as shown in Figure 20(c), thereby enabling the growth of seaweed SW in the vicinity of the inclined surface 50 of the inclined seawall D.

[0072] In Figures 20(a) to (c), the rope is shown in a single row, but multiple rows may be installed, and another row may be installed between another wave-dissipating block BL or between a covering block HB. This increases the growth area for seaweed, allowing for more efficient growth. In addition, the rope may be installed at an angle with respect to the x-axis between wave-dissipating block BL and covering block HB to allow for the growth of seaweed that prefers different water depths.

[0073] Figures 22(a) to (d) show an example of applying the seaweed cultivation device according to this embodiment to a gently sloping revetment. Figure 22 is a side cross-sectional view (a) showing the seaweed cultivation device according to this embodiment installed on a gently sloping revetment, a front view (b) of the seaweed cultivation device installed on numerous covering blocks of the gently sloping revetment shown in Figure 22(a) as seen from the direction of arrow bb in the same figure, a magnified side view (c) of a rope attachment device installed on a covering block on the sloping surface of the gently sloping revetment, and a magnified side view (d) of a rope attachment device installed on a covering block on the flat surface of the gently sloping revetment.

[0074] As shown in Figures 22(a) and (b), the gently sloping revetment R has numerous concrete flat covering blocks HB installed along a predetermined distance from the lower end underwater to the upper end near land and along the inclined surface 52 and the flat surface 53 that continues from the lower end. The seaweed growth device 40 shown in Figures 22(a) to (d) comprises a rope attachment device 41 attached to the leftmost covering block HB in Figure 22(b) installed on the inclined surface 52 of the gently sloping revetment R, a rope attachment device 42 attached to the rightmost covering block HB, a rope attachment device 43 attached to the leftmost covering block HB installed on the flat surface 53 of the gently sloping revetment R, a rope attachment device 44 attached to the rightmost covering block HB, a rope 45 stretched approximately horizontally between the rope attachment devices 41 and 42, and a rope 46 stretched approximately horizontally between the rope attachment devices 43 and 44. Furthermore, rope holding devices 47, 47 for holding the rope 45 are attached to the covering block HB between rope attachment devices 41 and 42, and rope holding devices 48, 48 for holding the rope 46 are attached to the covering block HB between rope attachment devices 43 and 44.

[0075] As shown in Figure 22(a), the gently sloping revetment R is composed of a gently sloping surface 52 and a flat surface 53, and the inclination angle θ2 of the gently sloping surface 52, which is gentler than the inclined surface 50 in Figure 20(a), is, for example, about 22 to 27° (1:2 to 2.5) with respect to the horizontal plane. In addition, covering blocks HB are laid on the flat surface 53 that continues from the lower end of the gently sloping surface 52.

[0076] The rope attachment devices 41 to 44 in Figures 22(a) to (d) may have the same configuration as the rope attachment device 31 in Figure 21(a). The rope holding devices 47 and 48 may have the same configuration as the rope attachment device 31 in Figure 21(a) or the rope holding device 35 in Figure 21(b).

[0077] By installing the seaweed growth device 40 shown in Figures 22(a) to (d) on the covering block HB installed on the gently sloping surface 52 and the flat surface 53 of the gently sloping revetment R, the ropes 45 and 46 are stably supported in the vicinity of the gently sloping surface 52 and the flat surface 53, and seaweed can reliably attach to and grow on the lateral ropes 45 and 46 as shown in Figures 22(c) and (d), thereby enabling the growth of seaweed SW in the vicinity of the gently sloping surface 52 and the flat surface 53 of the sloping revetment D.

[0078] Furthermore, in Figures 20(a)-(c) and 22(a)-(d), it is preferable to set the vertical position, the length of the protruding portion, and the installation angle of the rope attachment devices 31, 32 and 41-44 so that the water depth at which the ropes 34, 45, and 46 are installed is suitable for the growth of seaweed. For example, as shown in Figure 23(a), the rope attachment device 41A is configured with a long protruding portion and installed vertically to the inclined covering block HB. Also, as shown in Figure 23(b), the rope attachment device 43A is configured with a long protruding portion and installed vertically to the horizontal covering block HB.

[0079] Furthermore, in the case of a sloping revetment, the gentler the slope, the longer the slope length becomes, thus increasing the area of ​​seaweed beds. Since the amount of light per unit area is constant, adding lateral ropes to a steep slope does not significantly increase the amount of seaweed, whereas on a gentle slope, adding ropes can be expected to increase the amount of seaweed. From this viewpoint, a mixed slope shape, where the area suitable for seaweed growth at a suitable water depth is gently sloped and the rest is steep, is preferable. An example of applying a seaweed growth device to such a mixed slope revetment will be explained with reference to Figures 25(a) and (b).

[0080] As shown in Figure 25(a), the mixed-type sloping revetment F consists of a steeply sloping surface 91 corresponding to the covering block HBa laid at the upper end underwater, a steeply sloping surface 93 corresponding to the covering block HBb laid at the lower end, and a gently sloping surface 92 with a gentler angle of inclination corresponding to a plurality of covering blocks HB laid in between them. The water depth range T for seaweed SW growth exists within the gently sloping surface 92. The seaweed growth device 90 consists of a plurality of rope attachment devices 94 installed on each covering block HB and a plurality of ropes (not shown) stretched between the rope attachment devices, similar to Figures 22(a) to (d). Figure 25(b) shows a steeply sloping revetment F' which lacks the gently sloping surface 92 of Figure 25(a) and consists of a steeply sloping surface 99 similar to the steeply sloping surfaces 91 and 93. A plurality of rope attachment devices 94 are laid on the plurality of covering blocks HB laid on the steeply sloping surface 99. Figure 25(b) also shows the water depth range T for seaweed SW growth. Comparing Figure 25(a) and Figure 25(b), the mixed-slope revetment F in Figure 25(a) has a longer slope than the steep revetment F' in Figure 25(b). This allows for the installation of more rope attachment devices 94 within the seaweed growth water depth range T on the gently sloping surface 92, enabling the addition of more ropes. As a result, the seaweed bed area can be increased, leading to an increase in the amount of seaweed.

[0081] Next, an example of applying a seaweed growth device to a flat artificial stone covering area installed near the front (offshore) side of the sloping surface of a sloping seawall will be explained with reference to Figures 26 and 27. As shown in the side cross-section of Figure 26, a flat area K is constructed extending in the z-axis direction (offshore side) from the lower end of the sloping surface of the sloping seawall J. The flat area K mainly consists of a ground M made of calcia-modified soil on the original ground and an artificial stone covering area N made of artificial stones installed on top of the ground M so as to cover the ground M. The calcia-modified soil of the ground M is manufactured from dredged soil and steelmaking slag. The artificial stones of the artificial stone covering area N are substitutes for stone materials and are installed in the sea to cover the ground M, similar to covering stones. The artificial stone covering area N serves as a substrate for seaweed to attach, allowing seaweed to grow. The ground M made of calcia-modified soil has lower strength than the artificial stone covering area N, making it difficult for seaweed to attach.

[0082] In the artificial stone covering section N shown in Figure 26, there are cases where the artificial stone is partially absent, exposing the ground surface of the soil M. For example, as shown in the top view and side cross-section view in Figures 27(a) and 27(b), the ground surface of the soil M, which is made of calcia-modified soil, may be exposed between the artificial stone covering section N1 and the artificial stone covering section N2, resulting in the existence of an exposed calcia-modified soil section M0. While seaweed SW attaches to and grows in the artificial stone covering sections N1 and N2, the exposed calcia-modified soil section M0 lacks a substrate for seaweed attachment, preventing seaweed from attaching. As a result, the exposed calcia-modified soil section M0 becomes a non-growing area for seaweed, hindering the efficient formation of seaweed beds in the flat area K near the front of the sloping revetment J. To address this, a seaweed growth device 100 is installed in the exposed calcia-modified soil section M0, as shown in the side cross-section view in Figure 27(c).

[0083] In other words, the seaweed growing apparatus 100 in Figure 27(c) comprises rope attachment devices 101 and 102 fixed to the artificial stone N11 at the right end of the artificial stone covering section N1 and the artificial stone N21 at the left end of the artificial stone covering section N2, respectively, and a rope 104 stretched between the rope attachment devices 101 and 102 and installed above the exposed calcia-modified soil section M0. The rope attachment devices 101 and 102 may have the same configuration as the rope attachment devices 31 and 32 in Figure 21(a), and are fixed by inserting their rod-shaped protruding parts 31a (Figure 21(a)) into fixing holes formed in the artificial stones N11 and N21, and then filling the fixing holes with filler material. Furthermore, the rope attachment devices 101 and 102 are installed so as to protrude slightly upward or diagonally upward from the artificial stones N11 and N21, and the rope 104 installed between them is at approximately the same height as the artificial stones N11 and N21, becoming nearly horizontal above the exposed calcia-modified soil section M0. By attaching and growing seaweed SW on the rope 104 installed in this manner, a seaweed bed can be formed in the exposed calcia-modified soil section M0 in the same way as the artificial stone covering sections N1 and N2, and a seaweed bed can be efficiently formed in the flat area K. It is also conceivable to place artificial stones in the exposed calcia-modified soil section M0 to form an artificial stone covering section that serves as a base for seaweed attachment, but installing the rope 104 above the exposed calcia-modified soil section M0 as shown in Figure 27(c) is simpler and allows for quicker implementation. Furthermore, the rope 104 does not necessarily have to be at the same height as the artificial stones N11 and N21. For example, if the upper surface of the artificial stones in the artificial stone covering sections N1 and N2 is near the lower end of the seaweed growth depth, it is preferable to raise the rope 104 to a height above the lower end of the seaweed growth depth (but below the upper end).

[0084] Furthermore, it is preferable to install additional rope attachment devices 101 and 102 in the same manner according to the width in the x-axis direction of the exposed calcia-modified soil section M0 in Figure 27(a), thereby increasing the length of the rope. The installation positions of the rope attachment devices 101 and 102 may be within a flat area K extending in the z-axis direction, near the inclined surface of the inclined revetment J. Also, for example, if an artificial stone covering section is installed from the revetment side for a predetermined length, and there is no artificial stone covering section offshore but there is a ground made of calcia-modified soil, a rope attachment device can be installed in the same manner on the artificial stone covering section, another rope attachment device can be installed on the ground, and a rope can be installed between the two rope attachment devices to form a seaweed bed in the installation range of the rope extending offshore. Furthermore, if the rope is long, it is preferable to install the rope holding devices 31 and 35 in Figures 21(a) and 21(b) on the intermediate exposed calcia-modified soil section.

[0085] Furthermore, in the seaweed cultivation devices 10, 10A, 10B, 20, 30, 40, 80, 90, and 100 of this embodiment, spore bags or the like may be installed near the ropes after the ropes have been installed, or ropes with seed threads or the like attached may be installed. A spore bag is made by collecting mature seaweed from a natural seaweed bed, filling it into a bag, and floating it on the ropes of the seaweed cultivation device, thereby dispersing the seaweed seeds from the bag to the surrounding ropes of the seaweed cultivation device.

[0086] Alternatively, the ropes to which the seed threads are attached can be changed seasonally, allowing for the cultivation of different seaweed species, such as wakame and akamoku from winter to spring, and arame from autumn to winter. This can increase the annual amount of seaweed per unit area.

[0087] Seaweed growth may be promoted by placing fertilizers that supply iron and nitrogen to the surrounding area on the seabed, or by attaching them to rope attachment points 3 and ropes 14, 15, 24, 25, 14A, 14B, 14C, 34, 45, 46, 84, etc., that extend in the y-axis direction. In addition, nets may be placed around the outer perimeter to prevent damage from herbivorous fish. By these methods, seaweed can grow even in areas where it is difficult for seaweed to reproduce after the summer due to rising water temperatures and decreasing salinity. This expands the range in which seaweed can grow.

[0088] While embodiments for carrying out the present invention have been described above, the present invention is not limited to these, and various modifications are possible within the scope of the technical idea of ​​the present invention. For example, in the seaweed cultivation device 10 of Figure 1(a), a rope holding device 31 for holding the rope 14 may be installed on the front Q1 of the quay wall Q as shown in Figure 24, between the rope attachment devices 11 and 12. The rope 14 is held by passing it through the ring-shaped rope holding portion 31b of the rope holding device 31, thereby reducing the deflection of the rope 14. Similarly, in the seaweed cultivation device 20 of Figure 5(a), a rope holding device 31 may be installed between the rope attachment devices 21 and 22. Alternatively, the rope holding device 35 shown in Figure 21(b) may be used instead of the rope holding device 31.

[0089] Furthermore, in the seaweed growing apparatus according to this embodiment, not only the rope attachment parts 3 and 28 but also the protruding parts 2, 28, 31a, and 35a of the rope attachment device and rope holding device can be used as seaweed growing substrates.

[0090] Furthermore, although the seaweed cultivation device was installed on a seawall / quay in this embodiment, the installation location is not limited to these. For example, it may be on the outer surface of marine / port structures that come into contact with seawater, such as piles / floating piers, floating solar power generation facilities, or offshore wind power generation facilities installed along the coast. The seaweed cultivation device allows a rope to be installed at a predetermined distance from the outer surface, similar to the case of the front Q1 of the quay Q. Seaweed can then attach to the rope and grow in the vicinity of the marine / port structure, forming a seaweed bed.

[0091] Furthermore, although the rope is shown nearly horizontally in Figures 2, 6, 9(b), 10, 11, and 27(c), in reality, as the seaweed SW grows, it will sag to some extent due to its own weight. In this case, if necessary, the rope retaining device 31 in Figure 21(a) or the rope retaining device 35 in Figure 21(b) can be installed at intermediate positions (one or more) along the rope to reduce the sagging.

[0092] Furthermore, when installing ropes as shown in Figures 20(a)-(c), 22(a)-(d), and 25(a), the shortest distance from the wave-dissipating block BL or covering block HB to the rope is preferably about 1 to 100 cm. [Industrial applicability]

[0093] According to the present invention, seaweed can attach and grow near seawalls, quays, and marine / port structures, expanding the range in which seaweed can grow and allowing for the formation of wider seaweed beds, thereby contributing to an increase in blue carbon content. [Explanation of Symbols]

[0094] 1,1A fixed part 2,2A Protruding part 3,3A Rope attachment section 10,10A,10B,20,30,40,80,90 100 Seaweed growing device 11, 11A, 12, 13, 13A Rope attachment device 14,15,24,25,14A,14C,34,45,46,84,104 ropes 14B Rope with floating device 17 Anchor bolts 18 Rings (annular section) 19,19A Floating body 19a Hole (annular portion) 21, 22, 23 Rope attachment device 27 Protruding part 28 Rope attachment section 31, 32 Rope attachment devices, rope holding devices 31a Protruding part 31b Rope attachment section, rope holding section 33,35 Rope holding device 35a Protruding part 35b Rope holding section 41-44, 94 Rope attachment device 47,48 Rope holding device 50 Slope 51 Flat surface 52 Gentle slope 53 Flat surface 61, 62, 65 Rope attachment device 63 Rope attachment point 64 Protruding part 65A Fixed part 66 Rope attachment section 71 Rope attachment device 72 Fixed part 81, 82, 101, 102 Rope attachment device 83 Rope attachment section 91,93 Steep slope 92 Gentle slope Q Wharf Q1 front L Distance from front Q1 G Submarine ground BL wave-dissipating blocks D Sloping revetment HB coated block R gently sloping revetment F Mixed type of sloping revetment θ1,θ2 Tilt angle SW seaweed K flat region M ground M0 Calcia-modified soil exposed area N,N1,N2 Artificial stone covering part

Claims

1. At least two rope attachment devices attached to the front of a seawall or quay, or to the outer surface of a marine or port structure that is in contact with seawater, or to the ground, and spaced apart from each other, The system includes a rope that is installed so as to be stretched between at least two of the aforementioned rope attachment devices and is located in the sea, allowing seaweed to attach to and grow, The rope is supported by the rope attachment device at a predetermined distance from the front or outer surface of the seaweed growing apparatus.

2. The seaweed cultivation apparatus according to claim 1, wherein the rope attachment device comprises a fixing portion fixed to the front or outer surface, a protruding portion extending from the fixing portion, and a rope attachment portion provided at the tip of the protruding portion.

3. The seaweed growing apparatus according to claim 2, wherein the rope attachment portion is supported by the protruding portion and is configured to extend vertically or horizontally with respect to the front or outer surface and is a substrate for seaweed attachment.

4. The seaweed growing apparatus according to claim 2, wherein the protruding portion is configured to be extendable and retractable in the protruding direction.

5. The seaweed growing apparatus according to claim 2, wherein the protruding portion is configured to be movable in the vertical direction relative to the front or outer surface at the joint portion with the fixed portion.

6. The seaweed growing apparatus according to claim 1, wherein the rope is stretched across the front or outer surface in a horizontal, vertical, or inclined direction.

7. The seaweed growing apparatus according to claim 1, wherein multiple ropes are stretched across the front or outer surface at different distances from each other.

8. The seaweed growing apparatus according to claim 1, wherein each of the ropes is stretched across the front or outer surface at intervals in the longitudinal or transverse direction.

9. The seaweed cultivation apparatus according to claim 1, wherein annular portions for attaching and detaching the rope to the rope attachment portion are provided at both ends of the rope.

10. The seaweed cultivation apparatus according to claim 1, wherein a rope holding device for holding the rope is installed between the at least two rope attachment devices.

11. The rope has at least two floating bodies connected at both ends, The floating body is installed on at least two rope attachment devices so as to be able to move up and down in accordance with the fluctuations in the tide level. The seaweed cultivation apparatus according to claim 1, wherein the floating bodies move up and down in accordance with the fluctuation of the tidal level, so that the rope between the floating bodies is continuously positioned at a predetermined depth from the water surface.

12. The aforementioned rope attachment device is composed of a stake-like body. The seaweed growing apparatus according to claim 1, wherein the pile-like body is installed in the ground at a predetermined distance from the front or outer surface.

13. The seaweed growing apparatus according to claim 1, wherein the front surface or the outer surface is substantially upright.

14. The seaweed cultivation apparatus according to claim 1, wherein the aforementioned revetment is a sloping revetment.

15. The seaweed cultivation apparatus according to claim 14, wherein the rope attachment device is installed on a wave-dissipating block or covering block installed on the sloping revetment.

16. A method for forming a seaweed bed by installing the seaweed growth apparatus described in any one of claims 1 to 15 on the front surface, the outer surface, or the ground, thereby growing seaweed in the sea near the front surface or the outer surface.

17. A method for forming a seaweed bed by installing the seaweed growth device described in claim 14 or 15 on the front surface, thereby growing seaweed in the sea near the front surface, The aforementioned sloping revetment is a mixture of steep and gentle slopes, and the method for forming a seaweed bed is to form a seaweed bed on the gentle slope using the seaweed growth device.

18. A method for forming a seaweed bed by installing the seaweed growth apparatus described in claim 1 on the ground, thereby growing seaweed in the sea near the front surface, The aforementioned ground consists of modified soil placed on top of the original ground. The ground surface of the aforementioned ground is covered with a stone covering that allows seaweed to attach and grow. A method for forming a seaweed bed in a modified soil exposed area, wherein, when there is a modified soil exposed area adjacent to the stone covering area where the modified soil surface is exposed, a rope attachment device to which one end of the rope is attached is installed on the stone covering area, and the rope is placed above the modified soil exposed area between the rope attachment device and another rope attachment device to which the other end of the rope is attached.

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