JP7408498B2 - Scour suppression unit, underwater plant regeneration method - Google Patents

Description

The present invention relates to a scour suppression unit and an underwater plant regeneration method.

In many cases, it is desirable to actively grow seaweed after installing underwater structures, etc., from the viewpoint of environmental conservation and local fishery promotion. One way to do this is to grow seaweed after construction.

Here, a general outline of the life history of brown algae is as follows.
First, zoospores released from the mother algae settle on a substrate (such as an algae reef) and then germinate to form a gametophyte (female or male). Next, the spermatozoa released from the spermatozoa of the male gametophyte fertilizes the egg of the female gametophyte and germinates to form a spore body, which grows and passes through a young sporophyte. Becomes an adult.

Conventional methods for regenerating seaweed beds include transplanting seeds and seedlings (gametophytes attached to threads, etc.) into sea areas, and dispersing zoospores and the like within sea areas.
In the case of seedling transplantation, seedlings are usually collected from other sea areas or grown on land and then introduced into the sea area. In this case, there were problems such as depletion of resources and time-consuming production of seedlings, resulting in high costs.
In addition, in the case of dispersing zoospores, etc., the zoospores are dispersed into the sea area from the mother algae placed in a bag-like structure. In this case, there are problems such as difficulty in securing mother algae from which zoospores can be obtained and difficulty in controlling the spread of zoospores within the ocean area.

In addition, conventional seaweed bed creation methods are carried out as a separate project after construction, which poses issues such as increased costs and longer construction periods. In addition, special materials were required, and safety considerations had to be taken as it involved diving. In particular, conventional seaweed bed regeneration methods mainly involve transplanting mother algae and fixing them with plates, etc., which are time-consuming and require special equipment (underwater glue, plate base, seeding rope, etc.) for seaweed propagation. etc.) had to be used.
In addition, a method of distributing spores has been attempted in recent years, but it has been difficult to implement in some regions and locations because the mother algae that serve as a supply source have been depleted due to rock formations and other factors.

Patent Document 1 describes an underwater afforestation method in which plant seeds and seedlings are held in a holder, and the holder is fixed to a weight and submerged in water. However, in the method described in Patent Document 1, since the holding body is made of vegetable fiber, it is essential to fix the holding body to a weight, and if the holding body is insufficiently fixed, the holding body itself may flow out. There was a risk of it being damaged, and reliability was low.

Japanese Patent Application Publication No. 2002-315469

An object of the present invention is to provide a scour suppression unit that can easily regenerate seaweed beds.

The present invention solves the above problems by the following solving means.

(1) A container with a plurality of openings;
a plurality of weight bodies made of stone or concrete housed in the housing;
A scour suppression unit that is installed underwater and suppresses submerged ground from being scoured,
comprising a plurality of porous members to which plant gametophytes are attached and whose individual shapes are maintained within the scour suppression unit;
The porous member is a scour suppression unit that is housed in the housing body together with the weight body.

(2) In the scour suppression unit described in (1),
female gametophytes and female gametophytes are attached to one porous member in a colony number of 1:1 to 1:2;
A scour suppression unit featuring:

(3) In the scour suppression unit described in (1),
The porous member is
a male porous member to which male gametophytes are mainly attached;
a female porous member to which female gametophytes are mainly attached;
two types are housed in the container;
A scour suppression unit featuring:

(4) In the scour suppression unit according to any one of (1) to (3),
the porous member is at least one of a concrete block, Ryukyu limestone, and a seashell;
A scour suppression unit featuring:

(5) An underwater plant regeneration method using the scour suppression unit according to any one of (1) to (4),
a process of constructing an underwater structure;
arranging the scour suppression unit near the foundation of the underwater structure;
An underwater plant regeneration method comprising:

(6) In the underwater plant regeneration method using the scour suppression unit according to (5),
maintaining the scour suppression unit installed underwater even after the underwater structure is removed;
An underwater plant regeneration method characterized by:

According to the present invention, a scour suppression unit that can easily realize seaweed bed regeneration is provided.

It is a figure which shows the example of use of the scour suppression unit by this invention. FIG. 2 is an enlarged view of one of the scour suppression units 1. FIG. It is a figure which shows the process of producing the scour suppression unit 1. It is a figure which shows the calculation example of the coverage of the female gametophyte in a male and female porous member.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings and the like.

(Structure of scour suppression unit)
FIG. 1 is a diagram showing an example of use of a scour suppression unit according to the present invention.
In the example shown in FIG. 1, a plurality of scouring suppression units 1 are arranged close to a foundation 101 of a wind power generation device 100 installed in the sea, stacked together below the water surface 200. The scouring suppression unit 1 is also called a filter unit, and has been widely used in the past to suppress scouring of the underwater ground by waves and the like. Although not shown, a mat may be installed between the foundation 101 and the scour suppression unit 1 in some cases.

FIG. 2 is an enlarged view of one of the scour suppression units 1.
The scour suppression unit 1 of this embodiment includes a container 10, a weight body 20, and a porous member 30.

The container 10 is a bag-shaped net having an opening 10a. The material of the container may be metal or a rope made of plant fibers. The container 10 is sealed with a weight body 20 and a porous member 30, which will be described later, housed therein. Note that the container 10 is not limited to a bag-like form using a net, and may have other forms such as a box-like form having an opening.

The weight body 20 is a rock, concrete piece, or the like that has been conventionally used in a scour suppression unit (filter unit). The size of the weight body 20 is, for example, about the size of a human head, and is so large that it does not pass through the opening 10a of the container 10.

The porous member 30 includes many fine holes. As the porous member 30, for example, a concrete block can be exemplified. Further, although the figure shows a simple rectangular concrete block, a hollow concrete block for construction may also be used. Note that the porous member 30 may be made of Ryukyu limestone or a shell.
Further, the porous member 30 maintains its individual shape within the scour suppression unit 1. Here, "the individual shape is maintained within the scouring suppression unit 1" means that from the start of construction of the scouring suppression unit, that is, from lifting the container with a crane, etc., to suspending it to the bottom surface of the water. It refers to the physical properties of porous members that maintain their individual shapes even when forces such as live loads, dead loads, and impact loads are applied throughout the installation process. Specifically, the material has physical properties such that the compressive strength per unit area is at least about 4 N/mm ² or more. An example of a porous member that satisfies this condition is architectural concrete block (cavity block) 08 (class A) specified in JIS A 5406, but even if a higher-strength type of hollow block is used, good.

Further, the porous member 30 has a plant gametophyte attached thereto. The gametophyte may be either a female gametophyte or a female gametophyte, or both. In this embodiment, the female gametophyte and the female gametophyte are attached to one porous member 30.

FIG. 3 is a diagram showing a process of manufacturing the scour suppression unit 1.
First, the weight body 20 and the porous member 30 are each prepared. The porous member 30 is soaked in a culture solution 300 containing gametophytes to impregnate the porous member 30 with the gametophytes (FIG. 3(a)). Note that the porous member 30 may be impregnated with the gametophyte by pouring the culture solution 300 onto the porous member 30 using a hose or the like.
By performing such impregnation, the gametophyte can be attached to the porous member 30.

The porous member 30 to which the gametophyte is attached and the weight body 20 are housed in the housing body 10. Here, the proportion of the weight occupied by the porous member 30 is desirably 10% or more and 30% or less of the combined weight of the porous member 30 and the weight body 20. After accommodating a predetermined amount of the porous member 30 and the weight body 20 in the container 10, the container 10 is closed, thereby producing the scour suppression unit 1.

BACKGROUND OF THE INVENTION Various underwater structures such as wind power generators installed in the sea are often removed after completing their role. In such cases, conventional scour suppression units were also often removed as unnecessary. However, removing the scour suppression unit requires a lot of effort, time, and cost.
Since the scouring suppression unit 1 of this embodiment is provided with attached gametophytes, seaweed and the like germinate, and most of them grow on the scouring suppression unit 1 itself. Therefore, the scouring suppression unit 1 has the function of not only simply suppressing scouring, but also regenerating seaweed beds that were lost during construction of the structure. Then, the seaweed bed will flourish on the scouring suppression unit 1. Therefore, when removing an underwater structure such as a wind power generator, the scouring suppression unit 1 may be left as is, or the position may be temporarily shifted only for the part necessary for removing the foundation, and then removed after the removal of the foundation is completed. It is advisable to return it to its original location.
In this manner, by maintaining the scour suppression unit 1 underwater even after the underwater structure is removed, the regenerated seaweed bed can be left substantially intact. Furthermore, since it is not necessary to remove the scour suppression unit 1, it is very beneficial in terms of labor, time, and cost for removing the underwater structure.

(Plant gametophyte)
In the present invention, the term "plant gametophyte" means a male gametophyte or a female gametophyte of any plant.

The plant from which the gametophyte is derived is not particularly limited, but among multicellular organisms that reproduce by gametophytes, seaweed, which is a marine plant, is preferred. Seaweeds are classified into brown algae, red algae, and green algae, and among these, brown algae are particularly preferred.

Among brown algae, the order Laminaria: Laminariaceae, the order Laminaria: Laminaceae, the order Laminata: Lessoniaceae, and the order Laminaria: Sargassum are important species that form seaweed communities in coastal areas as large seaweeds, and therefore they are considered as plant gametes in the present invention. Preferably, the body is derived from these.
More specifically, the plant gametophyte in the present invention is preferably derived from the following.
Saccharina japonica (scientific name: Saccharina japonica), Saccharina japonica (scientific name: Saccharina japonica), Saccharina japonica (scientific name: Saccharina japonica), Saccharina japonica (scientific name: Saccharina) japonica), Saccharina angustata (scientific name: Saccharina angustata), Saccharina angustata (scientific name: Saccharina angustata), Scientific name: Saccharina longissima), Gaggara kelp (Scientific name: Saccharina coriacea), Cat kelp (Scientific name: Arthrothamnus bifidus), Gagome kelp (Scientific name: Saccharina sculpera)
Seaweed (scientific name: Undaria pinnatifida), Japanese flounder (scientific name: Undaria undarioides), blue seaweed (scientific name: Undaria peterseniana), belonging to the genus Wakame of the order Laminariaformes and the family Prunidae.
Lessoniaceae, Ecklonia cava (scientific name: Ecklonia cava), Kurome (scientific name: Ecklonia kurome), Arame (scientific name: Eisenia bicyclis, syn. Ecklonia bicyclis), Ecklonia stol (scientific name: Ecklonia stol) (omifera)

In the present invention, any method capable of isolating gametophytes from plants can be adopted as a method for isolating gametophytes, and is not particularly limited. For example, in the case of isolating algal gametophytes, the following methods may be used. .
First, reproductive organs (bud stock, ascus spots, etc.) are cut out, washed with sterile filtered seawater, etc., and zoospores are released into a container of sterile filtered seawater by a drying process. Next, the culture is continued until the zoospores land on the bottom and form gametophytes. After culturing, collect the female gametophytes (or male gametophytes) one by one using a pipette, etc. under observation using a stereomicroscope, and place them in a culture container (multiplate, etc.) to separate the female and male gametophytes. By culturing the cells, a female gametophyte and a male gametophyte can be obtained.
The female gametophyte and the male gametophyte may be subjected to a test to confirm their reproductive ability, a treatment to promote maturation of the gametophyte, or the like, as necessary, before being attached to the porous member.

(Porous member to which the gametophyte is attached)
In the present invention, a porous member to which gametophytes are attached is used.
Both the male gametophyte and the female gametophyte may be attached to one porous member, or only one of the male gametophyte and the female gametophyte may be attached.

When both a male gametophyte and a female gametophyte are attached to one porous member, the fertilization of gametes (sperm, eggs) can be efficiently carried out by a scour suppression unit equipped with such a porous member. This method can be used to easily regenerate seaweed beds.
In such a case, it is preferable that the numbers of colonies of male gametophytes and female gametophytes in the porous member be close to the same ratio (ie, number of colonies of male gametophytes: number of colonies of female gametophytes = 1:1). Preferably, the number of colonies of male gametophytes: the number of colonies of female gametophytes = 1:1 to 1:2.
In the present invention, a porous member in which both male gametophytes and female gametophytes are attached in a colony number of 1:1 to 1:2 is also referred to as a "hermaphroditic porous member."

When male gametophytes and female gametophytes are mainly attached to one porous member, in the scour suppression unit, near the porous member to which male gametophytes (or female gametophytes) are mainly attached, By arranging the porous member to which the female gametophyte (or male gametophyte) is attached, fertilization of gametes (sperm, eggs) is performed efficiently, and seaweed bed regeneration can be easily realized.
In the present invention, "mainly male gametophytes (or female gametophytes) are attached" means that 70% or more of the gametophytes present in the porous member are male gametophytes (or female gametophytes). Preferably 80% or more, more preferably 90% or more, even more preferably 100% are male gametophytes (or female gametophytes).
In the present invention, a porous member to which male gametophytes are mainly attached is also referred to as a "male porous member", and a porous member to which female gametophytes are mainly attached is also referred to as a "female porous member".

In the present invention, the amount of gametophytes (the number of gametophyte colonies) attached to the porous member is specified as "coverage". In the present invention, "coverage" (unit: %) means the ratio of the adhesion area of the gametophyte per unit area of the porous member. For example, as described later, the degree of coverage can be determined by photographing the surface of a porous member using an imaging device (digital camera, etc.), performing bivalent processing on the obtained image, and calculating the proportion of the gametophyte image in the image. It is identified by

(Method of attachment of gametophyte)
The method for producing the male and female porous members, the male porous member, and the female porous member is not particularly limited.
For example, any method of contacting the porous member with a solvent containing a desired amount of gametophyte (ie, male gametophyte and/or female gametophyte) to which the porous member is to be attached may be mentioned.
Methods for such contact include a method in which a part or the whole of the porous member is immersed in a solvent containing the gametophyte, a method in which a part or the whole of the porous member is coated with a solvent containing the gametophyte, or a method in which a part or the whole of the porous member is impregnated with a solvent containing the gametophyte. Examples include a method of spraying.

The solvent for storing the gametophyte is not particularly limited as long as it does not interfere with the growth of the gametophyte, but preferably includes a culture medium and sterilized filtered seawater.
Examples of the medium include PESI medium, commercially available liquid fertilizer for plants, and commercially available plant nutrients.
Examples of sterilized filtered seawater include seawater from which solid substances (for example, particle size of 1 μm or more) have been removed and which have been sterilized by any method. The seawater used may be artificial seawater or natural seawater.

Although the amount of gametophyte in the solvent is not particularly limited, the greater the amount of gametophyte attached to the porous member, the more likely the gametophyte will be attached to the porous member in a living state, and the more easily the effects of the present invention will be exerted.
For example, it is preferable to adjust the amount of gametophyte in the solvent so that the amount of gametophyte attached to the porous member is 2 to 25%.

The temperature at which the porous member is brought into contact with the solvent containing the gametophyte is not particularly limited, but is usually a water temperature of 16 to 24°C.

The time for contacting the porous member with the solvent containing the gametophyte is not particularly limited, but from the viewpoint of sufficiently adhering the gametophyte to the porous member, it is usually 1 to 6 hours, and at most about 12 hours. It is preferable that the scour suppression unit is placed in the sea area after the solvent containing the gametophyte and the porous member have been in contact for the above period of time.

(Method for determining coverage)
An example of how to specify coverage will be described below.
The entirety of the two porous members (concrete blocks) was soaked in PESI medium containing different amounts of female gametophytes for 1 hour each to obtain two male and female porous members.
Next, the surface of the porous member was photographed in macro mode (close-up photography) using a digital camera, and the resulting image was subjected to bivalent processing. The results are shown in FIG.
From each bivalent image, the proportion of the female gametophyte image (portion shown in black) to the entire screen was calculated, and the degree of coverage (1.94% or 24.23%) was calculated.

10 Container 10a Opening 16 Water temperature 20 Weight body 24 Water temperature 30 Porous member 100 Wind power generator 101 Foundation 200 Water surface 300 Culture solution

Claims (5)

a container having a plurality of openings;
a plurality of weight bodies made of stone or concrete housed in the housing;
A scour suppression unit that is installed underwater and suppresses submerged ground from being scoured,
comprising a plurality of porous members to which plant gametophytes are attached and whose individual shapes are maintained within the scour suppression unit;
The porous member is housed in the container together with the weight body,
Male gametophytes and female gametophytes are attached to one porous member in a colony number of 1:1 to 1:2;
Scour suppression unit. a container having a plurality of openings;
a plurality of weight bodies made of stone or concrete housed in the housing ;
A scour suppression unit that is installed underwater and suppresses submerged ground from being scoured,
comprising a plurality of porous members to which plant gametophytes are attached and whose individual shapes are maintained within the scour suppression unit;
The porous member is housed in the container together with the weight body,
Two types of porous members are housed in the container: a male porous member to which male gametophytes are mainly attached, and a female porous member to which female gametophytes are mainly attached .
Scour suppression unit. In the scour suppression unit according to claim 1 or 2 ,
the porous member is at least one of a concrete block, Ryukyu limestone, and a seashell;
A scour suppression unit featuring: An underwater plant regeneration method using the scour suppression unit according to any one of claims 1 to 3 ,
a process of constructing an underwater structure;
arranging the scour suppression unit near the foundation of the underwater structure;
An underwater plant regeneration method comprising: In the underwater plant regeneration method using the scour suppression unit according to claim 4 ,
maintaining the scour suppression unit installed underwater even after the underwater structure is removed;
An underwater plant regeneration method characterized by:

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