JP2000201567A - Seaweed bed creation method and seaweed bed created thereby - Google Patents

Abstract

(57) [Summary] [Problem] To provide a seaweed bed creation base optimal for growing perennial seaweed and a seaweed bed creation method using the same. A seaweed bed is provided on a foundation pile (11) on a ground (10).
It is constructed by installing the upper structure (200) on the lower structure (100) fixed by (0). The upper structure (200) includes first and second vertical wave-breaking plates (21).
0, 220) and the horizontal wave-absorbing plate (23
0). A landing block (300) is fixed on the horizontal wave plate (230). Landing block (30
0) is soaked in seawater (802) in a container (800) together with mother algae (810) before being fixed to the horizontal wave plate (200). The zoospores (82) released from the mother algae (810)
0) is landed on the landing block (300). A few months later, the perennial seaweed (20) grows on the implantation block (300) fixed to the horizontal wave plate (230).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a seaweed bed most suitable for artificially growing seaweeds, particularly perennial seaweeds, and a seaweed bed created by the method.

[0002]

BACKGROUND ART It is well known that a seaweed bed is a place where fish lay eggs, fry hide, and abalones and turtles grow. This type of seagrass bed has been protected by the fishermen since ancient times as an important place.

Further, in recent years, creatures growing in seaweed beds have degraded organic matter and taken in nitrogen and phosphorus discharged from cities to purify seawater and have become a serious social problem. This type of seagrass bed plays an important role from the viewpoint of environmental protection such as absorption of CO ₂ .

[0004]

However, this type of seagrass bed has disappeared due to the rapid reclamation of the vast coastal area in the inland sea and the inner bay area and the occurrence of rocky shore in the reef area.
It is said to have disappeared on the scale of several thousand ha even after the year.

[0005] For this reason, there is a social need to regenerate a seaweed bed or to newly construct a seaweed bed.

[0006] As an artificial seaweed bed, a mound created from natural stone or a concrete block has been known. In this method, the mound sinks due to scouring, and natural stones and concrete blocks are scattered on coasts where waves are intense, so that wave resistance is a problem. Furthermore, this kind of artificial seaweed bed occupies a large area because of its trapezoidal structure, but its internal space is filled with stones, so that it can be used as a seaweed bed only on the mound surface.

On the other hand, structures such as a breakwater structure and a wave-breaking structure have been conventionally known as a seawall or a breakwater. It has been observed that natural seaweed and the like adhere to this type of structure.

However, the seaweed attached to this kind of structure is called an annual algae, and the annual algae grown in the spring die in the summer, and environmental protection such as water purification and CO ₂ absorption throughout the year. Role cannot be expected.

Accordingly, an object of the present invention is to provide a method for creating a seaweed bed most suitable for growing seaweeds, particularly perennial seaweeds, and to provide a seaweed bed formed by the method.

[0010]

According to a first aspect of the present invention, there is provided a method for constructing a seaweed bed, comprising the steps of: installing a support structure having a pile driving hole on a seabed; and a foundation inserted through the pile driving hole. Driving a pile into the submarine base, fixing the support structure, and immersing the base and mother algae of seaweed in seawater in a container;
Releasing the zoospores from the mother algae into the seawater and landing on the base; and, on the support structure, the zoospores were substantially horizontally placed at a predetermined water depth position. Supporting the substrate.

In the present invention, the mother alga of the base and the seaweed are immersed in the seawater in the container, and the zoospores are released from the mother algae into the seawater to be implanted on the base. Therefore, compared with the case where the grown seaweed is physically implanted, the zoospores can be reliably implanted on the base.

Further, since the base is supported by the supporting structure fixed to the seabed ground by the pile, a stable seaweed bed can be constructed.

[0013] Furthermore, the zoospores that have been implanted on the base can grow into adults while responding to the environment in the sea area where the base is installed, and have a higher degree of environmental adaptability than those that land on adults.

According to a second aspect of the present invention, in the first aspect, the base is provided with irregularities suitable for landing of the zoos.

[0015] In this case, the area for the zoospores to land increases, and the zoosports have the property of easily landing on a vertical surface rather than on a horizontal plane. Because it is protected, a secure landing is possible.

According to a third aspect of the present invention, in the first or second aspect, the base is a horizontal wave-absorbing plate having a wave-absorbing hole.

This makes it possible to make the zoospores relatively quiet on the bed on which the zoospores are implanted, and to prevent the zoospores from falling off the base due to waves before the roots of the seaweed are formed.

According to a fourth aspect of the present invention, in the third aspect, the container containing the seawater surrounds the horizontal wave-absorbing plate, which covers the wave-absorbing hole of the horizontal wave-absorbing plate and serves as a bottom plate, and surrounds four sides. And a side plate.

In this case, the horizontal wave plate can be used also as the bottom plate of the container, and the trouble of taking the horizontal wave plate into and out of the container after the container is completed can be omitted.

The method for constructing a seaweed bed according to the invention of claim 5 is as follows:
Installing a support structure having a pile driving hole on the seabed ground, driving a foundation pile inserted into the pile driving hole into the submarine base, and fixing the support structure; On the body, a step of supporting the horizontal base almost horizontally at a predetermined water depth position, a landing block plate and a seaweed mother algae,
A step of immersing the zoospores in the seawater in a container, releasing the zoospores from the mother algae into the seawater, and landing the zoospores on the landing block; and landing the zoospores on the horizontal base. Fixing the block.

According to the present invention, instead of the horizontal wave-dissipating plate, the zoosport is landed on a landing block fixed to a horizontal base. Since the landing block is smaller than the horizontal base,
The work of putting the landing block in and out of the container is simplified. In addition, the work of fixing the landing block to the horizontal base can be performed on land, and when the horizontal base is previously set in the sea area, the horizontal base can be used as a scaffold, so that it is safe.

According to a sixth aspect of the present invention, in the fifth aspect, the landing block is formed with irregularities suitable for landing of the zoosport.

Also in this case, the area on which the zoosports land is increased, and the sprouts are protected from the waves by the convex and concave portions even after the landing blocks are installed in the sea area, so that reliable landing is possible. Become.

According to a seventh aspect of the present invention, there is provided a seaweed bed formed by the method according to any one of the first to sixth aspects.

The seaweed bed created by the above method is an optimum seaweed bed for growing seaweeds, especially perennial seaweeds.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

(Structure of Seaweed Bed Creation Base) FIGS. 1 and 2
Shows the construction state of the seaweed bed and the seaweed bed creation base according to the embodiment of the present invention. The seagrass bed shown in FIG. 1 illustrates a state around April of the following year after being created around November.

In FIGS. 1 and 2, this seaweed bed formation base is roughly divided into a lower structure 100 serving as a support structure.
And an upper structure 200 supported thereon, and, for example, four foundation piles 110 for supporting and fixing the lower and upper structures 100 and 200 on the seabed ground 10.

The lower structure 100 includes four foundation piles 110.
And a steel jacket 120 installed on the seabed ground 10. This steel jacket 12
0 is the foundation pile guide rod 122, beam 124 and bracing 1
26 is connected and fixed by, for example, welding.
In addition, a vertical wave breaking plate 128 is fixed to each of two of the four foundation pile guide rods 122 toward the inside and outside of the bay, respectively.

On the other hand, the upper structure 200 is made of precast concrete cast in advance with steel reinforced concrete (SRC). This upper structure 200
Has first and second vertical wave plates 210 and 220, a horizontal wave plate 230, a foundation pile guide rod 240, and a beam 250.

The first vertical wave-dissipating plate 210 is disposed facing the outside of the bay, and serves to cancel external waves coming from the outside of the bay. 212.

On the other hand, the second vertical wave-dissipating plate 220 is disposed facing the inside of the bay, and serves to cancel waves in the bay such as wake waves generated by navigation of a ship. The second vertical wave-dissipating plate 220 is also formed with a wave-dissipating slit 222 that penetrates away from its surface.

The first and second vertical wave plates 210 and 2
20 has its upper end height position set, for example, about 3 m higher than the water level of the sea surface at the time of high tide, assuming a state of a high wave.

Further, the first and second vertical wave plates 210,
220, the slits 212 and 2 for wave canceling formed respectively.
Reference numeral 22 is set to be 20 to 40% of the total surface area of each wave canceling plate.

The horizontal wave plate 230 disposed on the horizontal wave plate 230 between the first and second vertical wave plates 210 and 220
Is located well below the water level at low tide. The horizontal wave-absorbing plate 230 has a wave-breaking slit 232 that penetrates away from its surface. This horizontal wave plate 2
By providing 30, the energy loss rate (wave extinction rate) of the wave due to the seaweed bed creation base is almost stable regardless of the wave cycle.

Note that the first and second vertical wave plates 210 and 2
The wave-breaking slits 212, 222, and 232 formed in the horizontal wave-breaking plate 20 and the horizontal wave-breaking plate 230 may be water-permeable holes that allow water to pass therethrough before and after each wave-breaking plate. Various shapes can be applied.

The first and second vertical wave-breaking plates 21
0, 220 and the horizontal wave-absorbing plate 230 are connected by four foundation pile guide rods 240 and four upper and lower beams 250.

An anchor bolt 2 for fixing the landing block 300 shown in FIG.
A large number of protrusions 60 are formed.

As shown in FIG. 1, seaweeds, especially perennial seaweeds 20, which have been implanted in the state of zoospores, grow on the landing block 300. After being inserted into the anchor bolt 260 shown in FIG. 2, the landing block 300 is fastened and fixed on the horizontal wave plate 230 by a nut 310.

The thus constructed seaweed bed creation base is
By connecting a plurality of ridges in the direction of arrow A shown in FIG. 2, a detached shore can be constructed.

(Method of Constructing a Base for Creating a Seaweed Bed) Next, a method of constructing a substrate for creating a seaweed bed will be described with reference to FIGS.

First, as shown in FIG. 3, a plurality of temporary piles 112 are driven into the seabed ground 10. This temporary pile 11
A mounting table 114 on which the steel jacket 120 is mounted is formed at the upper end of 2.

Thereafter, as shown in FIG. 4, a steel jacket 120 is suspended and mounted on each mounting table 114 of the plurality of temporary piles 112 by a crane or the like (not shown).

After the mounting of the steel jacket 120 is completed, as shown in FIG. 5, the four foundation piles 1 are guided while being guided by the foundation pile guide rods 122 of the steel jacket 120.
10 is driven into the undersea ground 10. Thereby, the steel jacket 120 is stably installed on the seabed ground 10.

After that, as shown in FIG. 6, the upper structure 200 is installed on the steel jacket 120.
The upper structure 200 is previously formed on the ground. The upper structure 200 is suspended by a crane or the like, and a foundation pile guide rod 2 formed on the upper structure 200 is formed.
While the foundation pile 110 is inserted into the
00 is placed on the steel jacket 120.

Thereafter, as shown in FIG. 7, the grouting agent injection hose 130 is connected to the foundation pile guide rod 122 of the steel jacket 120, and the foundation pile guide rods 122, 240 of the steel jacket 120 and the upper structure 200 are connected. A grout agent is injected between and the foundation pile 110. By this operation, the foundation pile 110, the lower structure 100, and the upper structure 2
00 is fixedly connected, and the construction of the seaweed bed creation base is completed.

(Landing of zoospores on the landing block) In parallel with the construction of the above-mentioned seaweed bed creation base, the zoospores landing on the landing block 300 on land is shown in FIG. It is performed as shown.

In FIG. 12, seawater 8 is contained in a container 800.
02 is accommodated. In the seawater 802, a plurality of landing blocks 300 and a mother algae 810 of perennial seaweed collected by nature around November.

Between November and February, zoospores 820 are released from the mother algae 810 as shown in FIG. Therefore, as shown in FIG. 12, the landing block 300 is immersed in the seawater 802 for one day or night, for example, so that the zoosports 820 are placed on the landing block 300.

The oscillating element 810 is placed on the upper surface of the landing block 300.
It is preferable to form an uneven pattern 320 on the surface of the landing block 300 as shown in FIG. In the present embodiment, the uneven pattern 32
0 is formed by forming a plurality of grooves 322 having a width of 10 cm and a depth of 4 to 5 cm, but is not limited to this example.

(Installation of Landing Block) The landing block 300 on which the trocar 810 has landed is installed on the horizontal wave plate 230. The landing block 300 is formed with four holes (not shown), and four anchor bolts 260 projecting upward from the horizontal wave-absorbing plate 230 are inserted into the holes, so that the landing block 300 Horizontal wave plate 230
Installed on top. Thereafter, as shown in FIG. 1, by fastening a nut 310 to the upper end of the anchor bolt 260,
The landing block 300 is firmly fixed on the horizontal wave-absorbing plate 230.

The installation work of the landing block 300 is performed by placing an operator on the horizontal wave-absorbing plate 230.
That is, the horizontal wave-absorbing plate 230 is also used as a scaffold when the landing block 300 is installed. Therefore, the worker can safely perform the work on the horizontal wave-dissipating plate 230 serving as a stable scaffold.

Before the upper structure 200 is placed on the steel jacket 120, the landing block 300 is placed on land.
May be fixed on the horizontal wave plate 230 of the upper structure 200.

(Function of Seaweed Bed) Next, the function of the above seaweed bed will be described.

(1) This seaweed bed is composed of the lower and upper structures 1
Since 00 and 200 are firmly fixed on the ground 10 by the foundation pile 110, they can be a stable base on which seaweeds grow. In particular, even when this seaweed bed creation base is constructed on a sandy beach where sand movement is intense, the foundation pile 1
When the base 10 is driven deeper than the ground 10, a stable base can be constructed.

This seaweed bed is a wave-breaking structure and therefore has high wave resistance, and since it has a pile structure, there is no sinkage caused by scouring.

(2) The seaweed bed of this embodiment is installed on the ground 10 having a water depth of several tens of meters to several tens of meters.
Since the landing block 300 as an epiphytic base is installed near the water surface 12, an appropriate water depth and sunshine for seaweed can be secured. This landing block 300
Is preferably a distance at which sufficient light reaches the seaweed 20 disposed thereon, for example, a water depth of 1 to 5 m. In this way, the zoospores 810 that have been implanted on the implantation block 300 can have sufficient sunlight, so that the seaweed grown in spring, for example, the perennial seaweed 2
0 can perform environmental conservation functions such as water purification and CO ₂ absorption throughout the year.

(3) A landing block 30 as a base for the settlement
No. 0 is installed not on the seabed ground 10 but at a position where the water depth is shallow, so that invasion of herbivores such as sea urchins and fish can be prevented. This makes it possible to prevent seaweeds formed on the landing block 300, particularly perennial seaweeds, from being damaged.
In particular, as in the present embodiment, the first and second vertical wave breaking plates 21
When they have 0,220, they serve as physical barriers, so that the effect of preventing the damage of the perennial seaweed 20 is great.

(4) In this embodiment, since the first and second vertical wave plates 210 and 220 are disposed outside and inside the bay, respectively, the water area on the horizontal wave plate 230 therebetween is However, even if it is a sea area with rough waves, it can be a quiet area with few waves. Therefore, the landing block 3
Even if the period immediately after 00 is set, and before the roots of the seaweed 20 are still firmly fixed to the implantation block 300, the seaweed 20 is washed away or its stem breaks. Can be prevented.

(5) Lower structure 1 of this seaweed bed creation base
00 can be the base for the larvae to settle. This lower structure 1
The effect of collecting fishes that aim at the animals attached to 00 as bait, or the shading of the lower structure 100 or the eddy current generated thereby attracts the fishes, or the fish gathering by seeking the lower structure 100 as a refuge place. is there. Thereby, the biota in the sea area around the seaweed bed creation base can be enriched.

(Modification of Seaweed Bed) Next, as another embodiment of the present invention, a modification of the seaweed bed will be described with reference to FIGS.
This will be described with reference to FIG.

The seaweed bed formation substrate shown in FIG. 8 is different from the seaweed bed formation substrate upper structure 200 shown in FIG.
It has been changed to 0. The other points are the same as the structure shown in FIG.

In the upper structure 400, the first vertical wave breaking plate 210 is disposed only on the side of the foundation pile guide rod 240 arranged in the bay or offshore, and the first pile wave guide plate 240 located in the bay is The second vertical wave plate 220 is not provided.

According to the seaweed bed creation base shown in FIG.
In particular, the first vertical wave-breaking plate 210
Therefore, the region on the horizontal wave-dissipating plate 230 located on the inner side of the bay can be secured as a quiet region. Therefore, similarly to the case of the seaweed bed creation base shown in FIG. 1, it is possible to construct an optimum seaweed bed for growing seaweeds, particularly perennial seaweeds.

In the substrate for seaweed bed creation shown in FIG. 9, the upper structure 500 has first and second vertical wave breaking plates 210 and 220.
Are not provided together. The seaweed bed creation base shown in FIG. 9 is desirably installed in a sea area where waves are not intense.
Since the seaweed bed creation base has the horizontal wave-dissipating plate 230, the horizontal wave-dissipating plate 23 does not matter as described above regardless of the wave cycle.
It is possible to stably perform the wave-dissipating function by 0, and thereby the water area on the horizontal wave-dissipating plate 230 can be calm.

The seaweed bed formation base shown in FIG. 10 uses a precast lower structure 600 instead of the steel jacket 120 shown in FIG. This lower structure 600
Is constructed by connecting and fixing four foundation pile guide rods 610 with beams 620.

Although the steel jacket 120 shown in FIGS. 1, 8 and 9 is excellent in that it is lightweight, the use of the precast lower structure 600 shown in FIG. 10 prevents the generation of rust. There is an effect that can be.

The seaweed bed formation base shown in FIG. 11 is obtained by installing an upper structure 500 shown in FIG. 9 on a precast lower structure 600 shown in FIG. In addition,
Although not shown, the upper structure 2 shown in FIG. 1 is placed on the precast lower structure 600 shown in FIGS.
00 can also be set.

(Structure for growing seaweed) As shown in FIG. 1, instead of the structure for growing the seaweed 20 on the implantation block 300, for example, as shown in FIG. The seaweed 20 may be grown directly on the base.

When the seaweed bed shown in FIG. 14 is formed, as shown in FIG.
0 and the side plate 920 surrounding the four sides constitute the container 900. At this time, the slit 232 formed in the horizontal wave plate 230 is covered with the lid 912.

Seawater 802 is stored in this container 900. In the seawater 802 in the container 900, a perennial seaweed mother algae 810 collected by nature around November is soaked overnight, for example.

As a result, the zoospores 82
0 is released, and the released oscillating element 820 is landed on the horizontal wave-dissipating plate 230.

The surface of the horizontal wave-absorbing plate 23 is placed on the surface of the horizontal wave-absorbing plate 23 so that the zoosports 810 easily land on the upper surface of the horizontal wave-absorbing plate 230.
It is more preferable to form a plurality of uneven patterns similar to the uneven pattern 320 as shown in FIG.

This operation is performed on land in parallel with the operation of fixing the lower structure 100 to the seabed ground 10.
Then, the horizontal wave breaker 230 on which the oscillating element 820 is landed is placed.
Is installed on the lower structure 100 to complete the seaweed bed.

The horizontal wave-absorbing plate 230 on which the oscillating element 820 is landed has two vertical wave-absorbing plates 210 and 2 shown in FIG.
20 or one vertical wave breaking plate 210 shown in FIG. 8 may be integrated, or only the foundation pile guide rod 240 may be integrated as shown in FIG. In any case, when the container 900 is formed, a part other than the horizontal wave plate 230 can be used as a part of the container 900.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

For example, in the embodiment described above, the lower and upper structures 100 and 200 are supported and fixed on the seabed ground 10 by the foundation pile 110, but only the lower support structure 100 is fixed by the foundation pile 110. It may be supported on the seabed ground 10. In this case, the upper structure 200 is supported by the lower structure 100.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a bed for seaweed bed creation according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the seaweed bed creation base shown in FIG.

FIG. 3 is a schematic explanatory view showing a first construction step of the seaweed bed creation base shown in FIG. 1;

FIG. 4 is a schematic explanatory view showing a second construction step of the seaweed bed creation base shown in FIG. 1;

5 is a schematic explanatory view showing a third construction step of the seaweed bed creation base shown in FIG. 1.

FIG. 6 is a schematic explanatory view showing a fourth construction step of the seaweed bed creation base shown in FIG. 1;

FIG. 7 is a schematic explanatory view showing a fifth construction step of the seaweed bed creation base shown in FIG.

FIG. 8 is a schematic explanatory view of a seaweed bed creation base according to another embodiment of the present invention.

FIG. 9 is a schematic explanatory view of a bed for seaweed bed creation according to still another embodiment of the present invention.

FIG. 10 is a schematic explanatory view of a bed for seaweed bed creation according to still another embodiment of the present invention.

FIG. 11 is a schematic explanatory view of a bed for seaweed bed creation according to still another embodiment of the present invention.

FIG. 12 is a schematic cross-sectional view for explaining a method of landing a zoosport on the landing block shown in FIG. 1;

FIG. 13 is a schematic cross-sectional view showing an example of an uneven pattern formed on the landing block shown in FIG.

FIG. 14 is a schematic cross-sectional view for explaining a method of landing a zoosport on a horizontal wave-absorbing plate.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Lower structure 110 Foundation pile 120 Steel jacket 122 Foundation pile guide rod 200 Upper structure 210 First vertical wave breaking plate 212, 222, 232 Wave breaking slit 220 Second vertical wave breaking plate 230 Horizontal wave breaking Plate 240 Foundation pile guide rod 250 Beam 260 Anchor bolt 300 Landing block 310 Nut 320 Concavo-convex pattern 322 Groove 400,500 Upper structure 600 Precast lower structure 800,900 Container 810 Mother algae 820 Oscillator 910 Bottom plate 912 Lid 920 side plate

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Keiji Nishiyama 1-7-1 Kyobashi, Chuo-ku, Tokyo Toda Construction Co., Ltd. F-term (reference) 2B003 AA01 BB03 BB04 BB06 BB08 DD01 DD02 EE04 2B026 AB05

Claims (7)

[Claims] 1. A step of installing a support structure having a pile driving hole on a seabed, and a step of driving a foundation pile inserted into the pile driving hole into the submarine base to fix the support structure. And a step of immersing the mother alga of the base and the seaweed in seawater in a container, releasing the zoospores from the mother algae into the seawater and landing on the base, and on the support structure, Almost horizontally at a predetermined depth,
Supporting the base on which the zoospores have been implanted. 2. The seaweed bed creation method according to claim 1, wherein irregularities suitable for landing the zoospores are formed on the base. 3. The method according to claim 1, wherein the base is a horizontal wave plate having a wave hole. 4. The container according to claim 3, wherein the container containing the seawater is constituted by the horizontal wave-dissipating plate having a bottom plate that covers the wave-dissipating hole of the horizontal wave-dissipating plate, and side plates surrounding four sides. A method for creating a seaweed bed, characterized in that: 5. A step of installing a support structure having a pile driving hole on the seabed ground, and a step of driving a foundation pile inserted into the pile driving hole into the submarine base to fix the support structure. And a step of supporting a horizontal base substantially horizontally at a predetermined water depth position on the support structure; dipping a landing block board and a seaweed mother algae in seawater in a container; Discharging into the seawater and landing on the landing block; andfixing the landing block on which the zoospores have been landed on the horizontal base. How to create a seaweed bed. 6. The method for creating a seaweed bed according to claim 5, wherein irregularities suitable for landing the zoospores are formed on the landing block. 7. A seaweed bed formed by the method according to any one of claims 1 to 6.