Method for producing algae seed-based

Abstract

An object of the present invention is to provide a technique capable of efficiently promoting the growth of algae in the production of a seedbed.SOLUTION: The present invention provides a method for producing an algal seedbed comprising a predetermined adhesion step and an elongation step.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for producing an algal seed substrate. [Background technology]

[0002] From the perspective of environmental conservation and the promotion of local fisheries, it is often desirable to actively promote the growth of algae and other organisms after the construction of structures in or around the sea.

[0003] Known methods for growing algae in the ocean include using seed substrates and seed threads. In these methods, algal gametes are attached to the substrate or threads, which are then retained in the ocean and allowed to flourish, forming a seaweed bed. For example, as a method using seed threads, Patent Document 1 describes an underwater greening method in which plant seeds are held by a holder, and the holder is submerged in water while fixed to a weight. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-315469 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, in underwater greening methods using seed substrates, if the seed substrates, which are mainly covered with algae that have not yet grown (e.g., gametophytes or young sporophytes), are installed in the sea, they are susceptible to damage by shellfish and other organisms, hindering the growth of the algae. Therefore, there is a need for a technology that can efficiently promote the growth of algae in the production of seed substrates and the like.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technology that can efficiently promote the growth of algae in the production of seed substrates. [Means for solving the problem]

[0007] The present inventors have found that the above-mentioned problems can be solved by culturing algae on a substrate while satisfying certain installation conditions, and have completed the present invention. Specifically, the present invention provides the following.

[0008] (1) A method for producing an algae seed substrate, comprising: The manufacturing method comprises: an attachment step of attaching algal gametophytes and / or algal sporophytes to a surface of a mesh-containing substrate; After the attachment step, the substrate is inclined at an angle of 25° to 75° with respect to the bottom of the tank in a water tank, and an extension step is performed in which the substrate is cultured in the presence of a water flow. Including, The mesh size of the mesh is 4 mm or more, The velocity of the water flow is 10 cm / sec or more in a direction facing the surface of the base. Manufacturing method.

[0009] (2) The manufacturing method according to claim 1, wherein the velocity of the water flow is 30 cm / sec or less in a direction facing the surface of the substrate.

[0010] (3) The manufacturing method according to claim 1 or 2, wherein the direction of the water flow is approximately parallel to the bottom of the water tank.

[0011] (4) The elongation step is performed such that the photon flux density on the surface of the substrate is 30 μmol / m 2 / s or more 90μmol / m 2 The method according to any one of claims 1 to 3, wherein the method is carried out under bright conditions so that the temperature is 100°C / s or less.

[0012] (5) The method according to any one of claims 1 to 4, wherein the type of algae is a large brown algae. [Effects of the Invention]

[0013] According to the present invention, a technique is provided that can efficiently promote the growth of algae in the production of seed substrates. [Brief explanation of the drawings]

[0014] [Figure 1] 1A to 1C are diagrams showing examples of the shape of a substrate in the present invention. [Figure 2] FIG. 10 is a diagram showing the arrangement of the substrate and the like set in the embodiment. [Figure 3] FIG. 10 is a diagram showing the results of measuring the body length of algae in an example. [Figure 4] FIG. 10 is a diagram showing the relationship between the mesh size of the substrate and the water flow in the examples. [Figure 5] 10A and 10B are diagrams showing the installation angle of the base and the direction of the water flow set in the example. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0016] <Method for producing algae seed base> In one embodiment, the method for producing an algae seed substrate according to the present invention (hereinafter also referred to as the "production method of the present invention") comprises the following steps. An attachment step in which algal gametophytes and / or algal sporophytes are attached to the surface of a mesh-containing substrate. After the attachment step, an elongation step is performed in which the substrate is inclined at an angle of 25° to 75° relative to the bottom of the tank in the presence of a water flow. However, the mesh size must be 4 mm or more, and the water flow speed must be 10 cm / sec or more in the direction opposite the surface of the base.

[0017] Although underwater greening methods using seed substrates are widely used, when seed substrates with insufficiently grown algae (e.g., gametophytes or young sporophytes) attached are installed in the sea, they are susceptible to damage by shellfish and other organisms, which can hinder the growth of the algae. On the other hand, since it takes a long time (e.g., more than two months) to grow algae sufficiently, there was a need for technology that could efficiently promote algae growth in order to improve the efficiency of seed substrate production. Therefore, the present inventors conducted extensive research and found that the growth of algae can be efficiently promoted by a method including the above steps.

[0018] In the present invention, the term "algal seed substrate" includes a substrate having fully grown algae (for example, sporophytes having a body length of 3 to 10 cm) attached to the entire or part of the surface of the substrate. Fully grown algae have the advantage of being less susceptible to damage from shellfish and other prey, and less likely to be washed away within the sea.

[0019] In the present invention, the "surface of the substrate" corresponds to a support portion to which algae (gametophytes, sporophytes, etc.) can attach. The algae can attach to the entire or part of the surface of the substrate. The surface of the substrate may be any part of the member that constitutes the substrate, but in a preferred embodiment, it includes the mesh part and its surroundings.

[0020] In the present invention, "efficient promotion of algal growth" includes shortening the time required to obtain fully grown algae (e.g., sporophytes with a body length of 3 to 10 cm) from algal gametophytes or young algal sporophytes. For example, in conventional methods, it takes, for example, two months or more to obtain fully grown algae from algal gametophytes or young algal sporophytes. On the other hand, according to the present invention, the time required to obtain fully grown algae (that is, the total time required for the attachment step and elongation step in the present invention) can be shortened to, for example, 20 to 50 days.

[0021] Each step in the production method of the present invention will be described in detail below.

[0022] (1) Adhesion process The attachment step is a step of attaching algal gametophytes and / or algal sporophytes to the surface of a mesh-containing substrate.

[0023] (1-1) Foundation The substrate is not particularly limited, except that it has a mesh throughout or in part, and the lower limit of the mesh size of the mesh is 4 mm or more.

[0024] "Mesh size" is a unit that indicates the size of the mesh, and is also called the mesh size or pore size. In the present invention, the mesh size includes the side or diameter length of the opening surrounded by the wires or holes that make up the net. In a preferred embodiment of the present invention, all of the side or diameter lengths are 4 mm or more.

[0025] By setting the mesh size to 4 mm or more, the water flow during the elongation process described below is not impeded, and the algae growth promotion effect can be stably achieved. Furthermore, by setting the mesh size to 4 mm or more, it becomes easier to stably achieve the photon flux density requirements described below.

[0026] The lower limit of the mesh size of the mesh is 4 mm or more, preferably 4.5 mm or more, from the viewpoint of preventing water flow from being obstructed.

[0027] The upper limit of the mesh size of the mesh is preferably 30 mm or less, more preferably 25 mm or less, from the viewpoint of allowing the algae to more stably adhere to the surface of the substrate.

[0028] The shape of the mesh (holes, openings) is not particularly limited and can be any shape, but rectangular (square, rectangular, etc.), circular, etc. are preferred from the viewpoint of not interfering with the water flow in the elongation step described below. However, at least the maximum diameter of the openings satisfies the mesh size requirements described above.

[0029] The term "substrate having a mesh" includes a substrate in which a mesh is stretched over a space surrounded by a frame, and a substrate having holes on its surface (preferably a flat surface). In these embodiments, the entire frame and mesh, and the entire surface (preferably a flat surface) correspond to the "mesh-containing substrate."

[0030] Examples of a substrate having a mesh include a frame on which threads are stretched in a grid pattern (a lattice pattern) and a metal plate with multiple holes (punched metal). In these embodiments, algal gametophytes and / or algal sporophytes, which will be described later, can be attached mainly to the filaments, around the holes, etc.

[0031] When the mesh substrate is a frame on which filamentous materials are stretched in a grid pattern, the diameter of the filamentous materials is preferably 0.5 to 5.0 mm, from the viewpoint of allowing the algae to more stably adhere to the surface of the substrate.

[0032] When the mesh-containing substrate is a punched metal, the pitch (the distance between the centers of the holes) is preferably 150 to 350 mm, from the viewpoint of allowing the algae to more stably attach to the surface of the substrate.

[0033] The material of the substrate is not particularly limited as long as it can support algae and is not harmful to the ecosystem. Examples of materials for the substrate include metals (stainless steel, etc.), resins (biodegradable resins, reinforced resins, etc.), and fibers (hemp, cotton, etc.).

[0034] The substrate may be made of a single material or multiple materials. When the substrate is a frame on which thread-like materials are stretched in a grid pattern, the substrate may include a frame (made of, for example, resin) and thread-like materials (made of, for example, fiber). When the substrate is a perforated metal, the substrate may consist of metal only.

[0035] The shape of the entire substrate is not particularly limited, and examples thereof include a triangle, a rectangle (square, rectangle, etc.), a pentagon, a hexagon, a trapezoid, a circle, and the like. An example of the shape of the substrate is shown in Figure 1.

[0036] The size of the entire substrate is not particularly limited, and can be set appropriately depending on the amount of algal gametophytes and / or algal sporophytes to be attached, etc. The size of the entire base is preferably 50 to 100 cm on one side or in diameter.

[0037] In order to prevent the algal gametophytes and / or algal sporophytes attached to the surface of the substrate from falling off, any part of the surface of the substrate may be provided with an uneven surface (rough surface). In such a case, the depth of the irregularities is preferably 0.5 to 10 mm.

[0038] (1-2) Algal gametophyte and / or algal sporophyte "Algal gametophyte and / or algal sporophyte" includes the male gametophyte, female gametophyte, or sporophyte of any alga, and combinations thereof.

[0039] The algae is not particularly limited, but examples include brown algae, red algae, and green algae. Of these, brown algae are preferred, and large brown algae are more preferred, from the viewpoint that the effects of the present invention are particularly likely to be achieved.

[0040] Examples of brown algae include the Laminariales family, the Pycnonotaceae family, the Lessoniales family, and the Sargassaceae family. More specific and preferred examples of brown algae include: Laminariales, Laminaria family, Laminaria genus: Saccharina (scientific name: Saccharina japonica), Saccharina japonica (scientific name: Saccharina japonica), Saccharina japonica (scientific name: Saccharina angustata), Saccharina longissima (scientific name: Saccharina coriacea), Saccharina bifidus (scientific name: Arthrothamnus bifidus), Saccharina sculpera Wakame (scientific name: Undaria pinnatifida), Undaria undarioides, and Aowakame (scientific name: Undaria peterseniana) of the Laminariaceae family Ecklonia (scientific name: Ecklonia cava), Ecklonia kurome, Eisenia bicyclis (syn. Ecklonia bicyclis), and Ecklonia stolomifera are all members of the Lessoniaceae family and the Ecklonia genus. Of the above, wakame corresponds to large brown algae.

[0041] (1-3) Algae adhesion to the surface of the substrate There is no particular limitation on the method for attaching algal gametophytes and / or algal sporophytes to the surface of the mesh-containing substrate.

[0042] When attaching the algal gametophytes and / or algal sporophytes to the surface of the substrate, they may be used as they are, or may be chopped into pieces using a mixer or the like.

[0043] In a preferred embodiment of the present invention, in the attachment step, the algal gametophytes and / or algal sporophytes are placed in a liquid that does not inhibit their growth, in order to prevent them from drying out. In the present invention, examples of "liquids that do not inhibit the growth of algal gametophytes and / or algal sporophytes" include seawater, seawater medium (PESI medium), and the like.

[0044] The amount of algal gametophyte and / or algal sporophyte used is not particularly limited, but for example, it is 0.05 to 0.1 g (dry weight) / cm relative to the surface area of ​​the substrate (including the area of ​​the space surrounded by the frame and the holes opened on the surface). 2 may be.

[0045] The algal gametophytes and / or algal sporophytes can be attached by contacting them with the surface of the substrate (particularly around the mesh portion). For example, if the algal gametophytes and / or algal sporophytes are contained in a liquid, they can be efficiently attached by spraying the liquid onto the surface of the substrate.

[0046] In a preferred embodiment of the present invention, in the attachment step, after the algal gametophytes and / or algal sporophytes are brought into contact with the surface of the substrate, they are preferably cultured for a short period of time in an aquarium before proceeding to the elongation step described below. This culture allows the algal gametophytes and / or algal sporophytes to adhere more firmly to the surface of the substrate, making it less likely for the algal gametophytes and / or algal sporophytes to detach from the surface of the substrate.

[0047] When culturing for a short period of time in an aquarium, the size of the aquarium in which the substrate is placed is not particularly limited as long as it is large enough to accommodate one or more substrates. The arrangement of the substrates in the aquarium is not particularly limited, but from the viewpoint of increasing adhesion efficiency, it is preferable that the substrates are approximately parallel to the ground (for example, that the substrates are laid down on the bottom of the aquarium).

[0048] When culturing for a short period of time in an aquarium, it is preferable to fill the aquarium containing the substrate with a liquid that does not inhibit the growth of algal gametophytes and / or algal sporophytes, so that the entire substrate is submerged.

[0049] When culturing for a short period of time in an aquarium, the culturing time does not need to be excessive, and may be, for example, from the start of culturing until the gametophytes or sporophytes do not separate from the substrate when touched, or until young sporophytes are formed from the gametophytes. From this viewpoint, the culture time is preferably 5 to 20 days, more preferably 5 to 15 days.

[0050] When culturing for a short period of time in a tank, static culturing is preferred.

[0051] When culturing for a short period in an aquarium, the temperature condition is preferably 14 to 22°C from the viewpoint of the growth efficiency of the algae.

[0052] Other conditions in the attachment step (light / dark conditions, presence or absence of aeration, etc.) are not particularly limited, and any conditions that do not inhibit the growth of algal gametophytes and / or algal sporophytes can be employed.

[0053] Preferable specific methods in the attachment step include the following. Mix chopped algae gametophytes and sporophytes with a liquid that will not inhibit their growth, then spray it around the mesh part of the substrate. After spraying, immediately lay the substrate flat on the bottom of an aquarium that has already been filled with a liquid that will not inhibit the growth of algal gametophytes and / or algal sporophytes, and leave it there so that the entire substrate is submerged. · Culture under conditions that allow the growth of algal gametophytes and / or algal sporophytes (e.g., under aeration and light conditions, for 5 to 30 days). After confirming that the algae (sporophytes, gametophytes, etc.) are attached to the surface of the substrate, proceed to the elongation process described below.

[0054] (2) Extension process The elongation step is a step in which the substrate obtained after the attachment step is placed at an angle of 25° to 75° relative to the bottom of a water tank and cultured in the presence of a water flow, the water flow velocity of which is 10 cm / sec or more in the direction opposite to the surface of the substrate.

[0055] The present inventors have found that the growth of algae is promoted by setting the mesh size of the substrate to 4 mm or more and applying a water flow to the substrate so as to satisfy the above requirements. The reason for this is unclear, but is speculated as follows. When the above-mentioned base angle and water flow velocity are satisfied, the water flow can flow along the surface of the base. In such cases, the water flow can stagnate like a vortex as it passes through the algae on the base surface, slowing the flow velocity slightly. As a result, the algae have more and longer contact with the water flow, which is thought to promote their growth.

[0056] The water bath used in the elongation step may be the same as or different from that used in the attachment step.

[0057] The water tank used in the elongation step is preferably filled with a liquid that does not inhibit the growth of algal gametophytes and / or algal sporophytes, to the extent that the entire substrate is immersed therein. In the elongation step, the liquid in the water tank may be replaced as needed by pouring water into and draining water from the water tank.

[0058] (2-1) Installation of the base The installation angle of the base relative to the bottom of the tank is 25° to 75°, preferably 30° to 60°, and more preferably 35° to 55°.

[0059] In the present invention, the "bottom of the water tank" corresponds to a surface that is approximately parallel to the horizontal surface on which the water tank is placed.

[0060] The method for installing the base is not particularly limited as long as it can be fixed in a state inclined at an angle of 25° to 75° relative to the bottom of the tank, and examples thereof include the following methods. - Hang the base from the top of the aquarium and adjust the height to tilt the base at the desired angle. Once the base is tilted at the desired angle, use the fasteners to secure the base to the bottom of the tank. -Install a metal frame that can be tilted and fixed in place inside the aquarium, and then fix the base to the frame.

[0061] The number of substrates to be installed in the tank is not particularly limited, and one or more substrates may be installed. However, when multiple substrates are installed, it is preferable to arrange the substrates so that their surfaces are approximately parallel to each other and face each other with a gap between them, from the viewpoint of ensuring sufficient contact with the water flow described below. The gap between the substrates can be adjusted as appropriate within a range that does not stagnate the water flow.

[0062] (2-2) Generation of water flow In the elongation step, the substrate is placed at an angle as described above, and a water flow is generated in the direction opposite to the surface of the substrate at a speed of 10 cm / sec or more, and the culture is carried out. This process allows the algal gametophytes and / or algal sporophytes attached to the surface of the substrate to produce fully elongated algae (sporophytes, etc.), thereby providing an algal seed substrate.

[0063] In the present invention, the term "water flow" includes a water flow that is artificially generated in an aquarium under controlled conditions. For example, by using a water current generating device, it is possible to generate a water current with adjusted direction, speed, etc.

[0064] In the present invention, the term "direction facing the surface of the substrate" includes a direction facing one side or both sides of the surface of the substrate (the surface on which the mesh is located). The surface of the base has a mesh, so that the water flowing in the direction opposite to the surface of the base can penetrate the base.

[0065] Generally, the water current generated by the water current generating device circulates within the water tank. Therefore, in a preferred embodiment of the present invention, the water current is generated on both sides of the surface of the base in a direction penetrating the base. For example, when the installation angle of the base is 65° relative to the bottom of the tank, if a water flow is generated in a direction opposite to the surface of the base, the circulation of the water flow may cause the base to come into contact with the water flow not only from the side that forms an acute angle with the bottom of the tank (65°, see for example (A') in Figure 5), but also from the side that forms an obtuse angle (115°, see for example (A) in Figure 5).

[0066] The positional relationship between the base and the water flow generating device is not particularly limited as long as it can apply a water flow in a direction opposite to the surface of the base. In a preferred embodiment of the present invention, if the water flow generating device is placed on the side where the base forms an acute angle, the growth promoting effect can be more easily achieved.

[0067] The velocity of the water flow in the direction opposite to the surface of the substrate is 10 cm / sec or more, preferably 12 cm / sec or more, and more preferably 14 cm / sec or more. If the velocity of the water flow satisfies the above requirements, the contact between the water flow and the algae on the inclined substrate surface is likely to be large and long.

[0068] There is no particular upper limit to the speed of the water flow, but from the viewpoint of preventing the algae from being washed away due to excessive contact between the algae and the water flow, the speed is preferably 30 cm / sec or less, more preferably 25 cm / sec or less, in the direction opposite the surface of the substrate.

[0069] The velocity of the water flow can be determined by any flow rate sensor.

[0070] The direction of the water flow is not particularly limited as long as the water flow is generated in a direction opposite to the surface of the base, but from the viewpoint of stabilizing the direction of the water flow and making it easier to achieve the effects of the present invention, it is preferably approximately parallel to the bottom of the tank.

[0071] One or more water current generating devices can be placed in the water tank as long as the direction and speed of the water current specified in the present invention can be achieved. The water current generating device is not particularly limited, but may be a water current pump (circulator), a small propeller water current generating device (submersible mixer), or the like.

[0072] (2-3) Other conditions Any other conditions can be adopted in the elongation step as long as they do not inhibit the growth of the algae.

[0073] In the elongation step, by satisfying the above-mentioned conditions, the growth of the algae can be efficiently promoted. Therefore, the duration of the elongation step (i.e., the contact time between the algae and the water flow) does not need to be excessive. In a preferred embodiment of the present invention, the upper limit of the duration of the elongation step is preferably 30 days or less, more preferably 25 days or less. The lower limit of the time for which the elongation step is carried out is not particularly limited as long as the algae can be sufficiently brought into contact with the water flow, but it is preferably 15 days or more, more preferably 20 days or more.

[0074] The elongation step is preferably carried out under light conditions, from the viewpoint of more easily promoting the growth of the algae.

[0075] When the elongation step is carried out under light conditions, the photon flux density on the surface of the substrate is preferably 30 μmol / m from the viewpoint of facilitating stable algae growth. 2 / s or more 90μmol / m 2 / s or less, more preferably 40 μmol / m 2 / s or more 80μmol / m 2 It is preferable to adjust it so that it is / s or less. In such an embodiment, the light irradiated onto at least a portion (preferably the entire surface) of the substrate satisfies the above-mentioned photon flux density requirement. The photon flux density at the surface of the substrate can be measured by any light quantity sensor.

[0076] When the elongation step is carried out under light conditions, the number of light sources can be adjusted depending on the number of substrates, the size of the aquarium, etc., and can be any number equal to or greater than one.

[0077] When the extension step is carried out under bright conditions, the arrangement of the light source is not particularly limited as long as it can irradiate at least a portion (preferably the entire surface) of the substrate with light. For example, the light source arrangement is as follows: Fix the light source to the top of the tank (e.g., the ceiling). Surround the tank with reflective material (such as aluminum foil), and position the light source so that it hits the reflective material and illuminates the entire inside of the tank.

[0078] The temperature condition for the elongation step is preferably 14 to 22°C from the viewpoint of the growth efficiency of the algae.

[0079] The completion time of the elongation step can be set appropriately, for example, when the algae have grown sufficiently. For example, the following time points can be set as the completion time of the elongation step: When fully grown algae (e.g., sporophytes 3-10 cm in length) are observed on the surface of the substrate.

[0080] After the extension step, the resulting substrate can be used as a seed substrate for algae for various purposes. The obtained seed substrate may be used for various purposes as it is, or may be stored until use.

[0081] <Algal species base> The algal seed substrate obtained by the production method of the present invention can be used for any purpose, for example, in place of or in addition to a conventional seed substrate.

[0082] The seed substrate obtained by the manufacturing method of the present invention can be maintained in a sea area or the like, and by allowing the algae (sporophytes, etc.) on the seed substrate to flourish, a seaweed bed can be formed. Therefore, the seed substrate is suitable as a means of underwater greening in a sea area or the like. For example, the seed base can be fixed to the side of a coastal structure (bridge pier, revetment, submerged breakwater, artificial fishing reef, offshore wind power bottom-mounted foundation, etc.) and allowed to grow, forming a seaweed bed. Fixing nuts can be used to fix the seed base.

[0083] For example, if the substrate is made of a biodegradable resin, the algae seed substrate will decompose after being placed in the sea area, and the roots of the algae will be able to firmly attach to the coastal structure.

[0084] After the seed substrate is installed in the sea, if the algae fall off or weaken due to unexpected influences (high water temperatures due to abnormal weather, typhoons, etc.), new seed threads (threads with algae attached) can be fixed to the remaining substrate, and the substrate can be reused. Furthermore, if the sea area where the seed base is installed has a bad environment (muddy water, etc.), the seed base can be quickly retrieved and reinstalled in another sea area, etc. [Example]

[0085] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0086] <Test 1: Preparation of seed substrate> A seed substrate was prepared by the following method, and the growth efficiency of algae on the surface of the substrate was confirmed.

[0087] (1) Preparation of the foundation A square substrate having a grid-like mesh as shown in FIG. 1(A) was prepared. The base is made of a stainless steel outer frame and a grid (mesh), with a mesh size of 5 mm, a wire diameter of 0.5 mm, and a thickness of 0.5 cm. The length of one side of the base is 50 cm.

[0088] (2) The process of algae attachment to the substrate In this example, a large brown alga (scientific name: Undaria pinnatifida) was selected as the algae. First, the male and female algal gametophytes were chopped into pieces of several millimeters in size using a mixer. The chopped gametophytes were mixed and scattered on the substrate (especially around the mesh). After spraying, the substrate was immediately placed on the bottom of a tank containing a medium in advance, so that the substrate was completely submerged, and the substrate was left to stand, and cultured under aerated and bright conditions. Two to four weeks after the start of culture, it was confirmed that young sporophytes were formed from the gametophytes and that the formed sporophytes did not come off the substrate when touched (they were attached to the surface of the substrate).

[0089] In this example, a known seawater medium (PESI medium) was commonly used as the medium.

[0090] (3) Algae elongation process The substrate was transferred to another tank containing culture medium. Specifically, the five bases were installed at an angle of approximately 65° (115° obtuse angle) relative to the bottom of the tank. In this example, the installation angle of the bases was fixed by suspending the bases with a string from a pipe (not shown) hanging above the tank. The substrates were arranged at 15 cm intervals so that the substrate surfaces faced each other parallel to one another.

[0091] FIG. 2 shows a schematic diagram of the arrangement of the substrate and the like (in this diagram, the side surface of the substrate in the thickness direction is shown, and the surface of the substrate is not visible). A drain was installed on the side of the tank opposite the side where the water current generator was installed. The amount of water discharged from the tank was adjusted so that the water in the tank was replaced every 3 to 4 hours.

[0092] A water flow (10-20 cm / sec) was generated on the surface of each tilted substrate (the entire mesh surrounded by the outer frame of the substrate) in a direction opposite to the surface of the substrate and approximately parallel to the bottom of the tank using a water flow generator (product name "Vestawave", manufactured by Volks Japan Co., Ltd.) installed in the tank.

[0093] In this example, the water current generator was placed on the side where the base made an obtuse angle with the bottom of the tank (see Figure 2). However, the water does not flow in one direction inside the tank, but rather circulates around the tank as it hits the sides of the tank. Therefore, although the water flows onto the base in this example mainly from the side that forms an obtuse angle with the tank bottom, water also flows onto the base from the side that forms an acute angle with the tank bottom.

[0094] After the installation of the substrate, the substrate was cultured (contact between the substrate and the water flow) for 13 days to allow the algae to grow and obtain the seed substrate. The culture was carried out under bright conditions. A light source was fixed from the ceiling facing the tank, and the light intensity was adjusted so that the photon flux density on the surface of the substrate was 40 to 80 μmol / m 2 It was adjusted to / s.

[0095] The control was an example in which a substrate was set up in the same manner as above, except that no water flow was generated (water flow: 2 cm / sec or less), and culture was carried out.

[0096] In this example, the water flow was measured using an "ACM200A flow velocity sensor" (manufactured by Alec Electronics Co., Ltd.). The photon flux density was measured using a handheld light quantity sensor ("MQ-200X", manufactured by Apogee).

[0097] (4) Results The length of the algae (sporophytes) in each group was measured at the start of the elongation process (day 0) and at the end of the elongation process (day 13), and the average value was calculated. The results are shown in Figure 3. As shown in Figure 3, contact of the water flow with the surface of the substrate significantly promoted the growth of algae (sporophytes).

[0098] Although data are not shown, in culture, low photon flux densities (e.g., 40 μmol / m 2 / s), it was difficult to observe a stable promoting effect on sporophyte elongation.

[0099] The sporophytes obtained in this example (shown in Figure 3 on the 13th day with "current" in the figure) were placed on a seawall in the marine area, approximately perpendicular to the water surface, and it was confirmed that the algae had taken root well.

[0100] <Test 2: Examination of the relationship between mesh size and water flow> As shown in Test 1 above, in order to efficiently prepare a substrate, it is necessary to bring the substrate into sufficient contact with the water flow during the extension step. On the other hand, if the mesh size of the substrate is not appropriate, the substrate may impede the water flow and not be effective enough in promoting the growth of algae. Therefore, in this example, we investigated an appropriate mesh size for the base that would not impede the water flow.

[0101] The base was tilted and placed in the tank in the same manner as in Test 1, except that the mesh size of the base was set to either 0 (a flat base with no mesh at all) or 60 mm, and a water flow was generated under the same conditions as in Test 1. As a result, it was found that in order to generate sufficient water flow (10 cm / sec or more) throughout the tank, the mesh size of the substrate must be set to 4 mm or more, as shown in Figure 4. In Figure 4, the intersection of the line graph and the dashed line indicating the "minimum flow rate required for algae growth" is the point where the mesh size is 4 mm and the water flow is 10 cm / sec.

[0102] In addition, if the mesh size of the substrate is 4 mm or more, sufficient photon flux density (40 to 80 μmol / m 2 / s) was easy to achieve.

[0103] <Test 3: Examination of the relationship between substrate angle and algae growth efficiency> In Test 1, the base was installed at an angle of approximately 65° acute angle (115° obtuse angle) relative to the bottom of the tank, and the water flow generator was placed on the side where the base made an obtuse angle relative to the bottom of the tank. Therefore, as shown in Figure 5, we changed the installation angle of the base and the position of the water flow generator to examine the effect on the growth of the algae (sporophyte).

[0104] As shown in Figure 5, water was applied to the substrate under the following five conditions. The other conditions were the same as in Test 1. (A) The base was tilted at an acute angle of approximately 65° to the bottom of the tank, and the water flow generator was placed on the side where the base made an obtuse angle (115°) to the bottom of the tank. In other words, the conditions were the same as in Test 1. (A') The base was set at an acute angle of approximately 65° relative to the bottom of the tank, and the water flow generator was placed on the side where the base made an acute angle (65°) with the bottom of the tank. In other words, the water flow generator was placed on the opposite side from Test 1. (B) The base was placed at an acute angle of approximately 10° relative to the bottom of the tank, and the water flow generator was placed on the side where the base made an obtuse angle (170°) relative to the bottom of the tank. (B') The base was placed at an angle of approximately 10° to the bottom of the tank, and the water flow generator was placed on the side where the base made an acute angle (10°) with the bottom of the tank. (C) The base was placed at an angle of approximately 90° to the bottom of the tank, and the water flow generator was placed on one side of the base.

[0105] As a result, in (A) and (A'), sporophyte elongation was promoted stably. This was presumably because the water flowed along the surface of the substrate (the entire mesh surrounded by the outer frame of the substrate), evenly hitting the gametophytes and sporophytes. Furthermore, (A') tended to have a more stable effect than (A). In (A'), the water flow enters from the acute angle of the substrate, so a portion of the water flow flows downward along the substrate surface. This stagnates like a vortex at the acute angle between the bottom of the tank and the substrate, resulting in more and longer contact between the gametophyte and the water flow (i.e., the water reaches the gametophyte and sporophyte evenly).

[0106] In both (B) and (B'), sporophyte elongation was difficult to observe. In particular, in (B), sporophyte elongation was almost nonexistent. This was presumably because the water flow did not sufficiently follow the surface of the substrate and did not evenly reach the gametophytes and sporophytes.

[0107] In (C), the elongation of the sporophyte was even less evident than in (B) and (B'). This was presumably because the water flow only penetrated the mesh of the substrate, without running along the surface of the substrate, and therefore did not evenly reach the gametophytes and sporophytes.

Claims

1. 1. A method for producing an algae seed substrate, comprising: The manufacturing method comprises: an attachment step of attaching algal gametophytes and / or algal sporophytes to a surface of a mesh-containing substrate; After the attachment step, the substrate is inclined at an angle of 25° to 75° with respect to the bottom of the tank in a water tank, and an extension step is performed in which the substrate is cultured in the presence of a water flow. Including, The mesh size of the mesh is 4 mm or more, The velocity of the water flow is 10 cm / sec or more in a direction facing the surface of the base. Manufacturing method.

2. The manufacturing method according to claim 1 , wherein the velocity of the water flow is 30 cm / sec or less in a direction facing the surface of the substrate.

3. The manufacturing method according to claim 1 , wherein the direction of the water flow is approximately parallel to the bottom of the water tank.

4. The elongation step is performed so that the photon flux density on the surface of the substrate is 30 μmol / m ２ / s or more 90μmol / m ２ The method according to claim 1, wherein the method is carried out under bright conditions so that the temperature is 1000 K / s or less.

5. The method according to claim 1 , wherein the type of algae is a large brown algae.

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