JP2004173521A

JP2004173521A - Method for installing adhesive substrate for underwater organism

Info

Publication number: JP2004173521A
Application number: JP2002340667A
Authority: JP
Inventors: Hisami Arai; 久美新井; Misao Suzuki; 操鈴木; Tatsuto Takahashi; 達人高橋
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 2002-11-25
Filing date: 2002-11-25
Publication date: 2004-06-24
Anticipated expiration: 2022-11-25
Also published as: JP3915676B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for installing an adhesive substrate with which underwater organisms such as seaweed or coral can effectively be made to adhere onto the adhesive substrate installed in water and grow thereon without carrying out a special treatment or processing for promoting the adhesion onto the substrate. <P>SOLUTION: The method for installing is carried out as follows. The adhesive substrate at pH≤10 is installed in water so as to satisfy conditions of formula (2) in the relationship between the thickness δ of a boundary layer formed on the upper surface of the adhesive substrate specified by formula (1) and the diameter D of zoospores, eggs or larvae of the organisms to adhere onto the adhesive substrate surface and grow thereon. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明が属する技術分野】
本発明は、海藻や珊瑚等のような水中生物を着生させるべき着生基質（基盤）を水中に設置する方法に関するもので、海藻や珊瑚等を基質に効果的に着生させることができ、特に藻場（藻礁）や珊瑚礁等の造成・修復に好適な方法を提供するものである。
【０００２】
【従来の技術】
ホンダワラ類やアラメ、カジメ、コンブ等の海藻が群落する藻場は沿岸海域における海中動植物の生産の場であり、有用魚介類や海藻の生息場、魚介類の産卵場、稚仔魚の成育場、餌場等として不可欠な場所であると言える。また最近では、海水中の窒素やリンが海藻に取り込まれ或いは藻場内の食物連鎖を通じて他の生物に取り込まれることにより除去されることや、藻場内で懸濁物質が沈降して水中から取り除かれることなど、藻場の水質浄化作用についても注目されつつある。
【０００３】
しかし、近年、藻場は沿岸の埋め立てや海水の汚濁などの影響により急速な消失、衰退が続いており、特に最近では、多くの沿岸海域で所謂“磯焼け”と呼ばれる現象が発生し、大きな問題となっている。このため最近では、消失、衰退した藻場を回復させるための対策（藻場造成）が各地で行われるようになってきた。
従来行われている藻場造成の手法の一つに、藻場を造成したい場所に、海藻を育成するための基質（通常、コンクリートブロック等）を設置して、この基質に海藻の種苗や母藻を移植し、必要に応じて海藻育成のためのメンテナンスを行う方法がある。しかし、この方法は基質への種苗の移植や基質設置後のメンテナンスに手間と費用がかかり、大規模な藻場造成には適していない。したがって、藻場造成の基本的な手法としては、基質を種苗の移植等を行うことなくそのまま藻場造成場所に設置し、且つ設置した後はメンテナンスフリーで海藻を着生・生育させることが必要があると考えられる。
【０００４】
【発明が解決しようとする課題】
従来、藻場造成場所に設置される着生基質としては、製造の容易さ、海中での安定性、製造コスト等の面からコンクリートブロックが広く用いられている。しかし、コンクリートブロックを着生基質として単に海底に設置しても、十分満足できるような量の海藻を着生・生育させることができないという問題がある。このためブロックの基質面に凹凸や溝を付けたり、着生促進物質を塗布又は添付したり、或いは基質中に着生促進物質を添加するといった海藻着生を促す対策（例えば、特許文献１、特許文献２、非特許文献１）も試みられているが、その効果は必ずしも明確でなく、また、着生促進を目的として基質面に特別な加工や処理を加えたり、基質中に着生促進物質を添加したりすることは、藻場造成のコスト面からも問題がある。
【０００５】
【特許文献１】
特開２００１−２７５５０６号公報
【特許文献２】
特開２００２−４５０８０号公報
【非特許文献１】
「第５４回セメント技術大会講演要旨２０００」ｐ．４１０−４１１
【０００６】
したがって本発明の目的は、基質面に着生促進のための特別な処理や加工を施したり、基質中に着生促進物質を添加したりしなくても、水中に設置した着生基質に海藻や珊瑚等の水中生物を効果的に着生・生育させることができる着生基質の設置方法を提供することにある。
【０００７】
【課題を解決するための手段】
本発明者らは、海中に設置された着生基質面に海藻等の遊走子や卵等が着生して幼体まで成長するための諸条件について検討を行う過程で、着生基質表面に形成される境界層に着目し、この境界層が海藻等の遊走子や卵の着生・生育に及ぼす影響について詳細な実験と検討を行った。その結果、この着生基質表面に存在する海水の微小環境域（境界層）が海藻の遊走子や卵の着生・生育に大きく関与していることが判った。すなわち、海藻の繁殖形態は、胞子体（親個体）から放出された遊走子や卵が海水中を浮遊して基質に到達し、その表面に着生した後、幼体、さらには胞子体へと成長するものであるが、遊走子や卵が基質表面に到達した際に基質表面に適切な厚さの境界層が形成されていると、遊走子や卵が境界層の中に取り込まれ（すなわち基質表面から再離脱しない）、この境界層が遊走子や卵が着生・生育する環境（領域）となる。そして、境界層の水質は基質自体の組成や性質に大きく支配されるため、基質の組成や性質により境界層の水質環境が遊走子や卵の着生・生育に適したものであれば、境界層内の遊走子や卵は基質表面に適切に着生し、生育することになる。すなわち、基質表面に遊走子や卵を適切に着生させ、幼体まで生育させるには、基質に到達した遊走子や卵を取り込むことができる適切な厚さを有し、且つそれらの着生・生育に適した水質環境を有する境界層を基質表面に形成させる必要があることが判った。そして、そのような境界層を形成するための方策についてさらに検討を進めた結果、基質として所定レベル以下のｐＨを有するものを用いるとともに、その基質を、着生させるべき生物の遊走子や卵等の直径以上の厚さの境界層が形成されるような海中環境下に設置することが必要であることが判った。
【０００８】
本発明はこのような知見に基づきなされたもので、その特徴は以下の通りである。
［１］水中の基質に着生して成長する生物用の着生基質を水中に設置する方法において、ｐＨ１０以下の着生基質を、下記（１）式で規定される着生基質の上部面に形成される境界層の厚さδが、着生基質表面に着生・生育させるべき生物の遊走子、卵又は幼生の直径Ｄ（但し、遊走子、卵又は幼生が球形でない場合はその長径）との関係で下記（２）式の条件を満足するよう、水中に設置することを特徴とする水中生物用の着生基質の設置方法。
【数２】

【０００９】
［２］上記［１］の設置方法において、着生基質がｐＨ７．５〜９．５であることを特徴とする水中生物用の着生基質の設置方法。
［３］上記［１］又は［２］の設置方法において、着生基質表面に着生・生育させるべき生物が、海藻、珊瑚、貝類、フジツボ類、ゴカイ類の中から選ばれる１種以上であることを特徴とする水中生物用の着生基質の設置方法。
［４］上記［１］〜［３］のいずれかの設置方法において、着生基質が、カルシウム成分として実質的に炭酸カルシウムのみを含むことを特徴とする水中生物用の着生基質の設置方法。
［５］上記［１］〜［４］のいずれかの着生基質の設置方法により水中に設置された水中生物用の着生基質。
【００１０】
【発明の実施の形態】
以下、本発明による水中生物用の着生基質の設置方法の詳細と好ましい実施形態について説明する。なお、以下においては、着生基質を海中に設置する場合を例に説明する。
本発明は、着生基質を海中に設置するに当たり、着生基質の表面に海藻等の遊走子や卵を取り込み且つこれらを適切に着生・生育させることができる微小環境領域、すなわち特定の厚さと水質を有する境界層を形成することを狙いとしている。
【００１１】
このため本発明では、まず、着生基質としてｐＨ１０以下の基質を用いる。
通常の海水のｐＨは７．８〜８．４程度の弱アルカリであるが、そのｐＨが１０を超えると遊走子や卵の着生や生育が著しく阻害される。ここで、着生基質表面に形成される境界層は、基質に接する流動性が低い微小厚の海水層であるため、そのｐＨは基質自体のｐＨと略同じになり、したがって、境界層のｐＨを遊走子や卵の着生・生育に適したｐＨ１０以下とするには、ｐＨ１０以下の着生基質を用いる必要がある。図１は、ｐＨ１０の基質とｐＨ１２の基質について、基質−境界層−境界層外のｐＨの遷移の概略を示したものである。一般のコンクリートのｐＨは略１２であり、したがってコンクリート製の基質表面に形成される境界層も略ｐＨ１２となり、この境界層は遊走子や卵が極めて着生・生育しにくい環境であると言える。また、本発明で用いる着生基質のより好ましいｐＨは７．５〜９．５であり、これにより境界層のｐＨも略同じｐＨとなる。
【００１２】
さらに、着生基質表面に形成される境界層の条件としては、境界層の厚さが基質に着生・生育させるべき生物の遊走子や卵等の直径よりも大きいことが必要であり、具体的には、下記（１）式で規定される、着生基質の上部面に形成される境界層の厚さδが、着生基質表面に着生・生育させるべき生物の遊走子、卵又は幼生の直径Ｄとの関係で下記（２）式の条件を満足するよう、着生基質を海中に設置することが必要である。なお、後述するように境界層の厚さは遊走子や卵等をその内部に完全に取り込むための条件として規定されるものであるため、遊走子、卵又は幼生が球形でない場合は、その長径をもって上記直径Ｄとする。
【数３】

【００１３】
本発明において、境界層の厚さδを上記（２）式のように規定するのは、海水の流れに乗って着生基質表面に到達した遊走子や卵などが、再び海水の流れに乗って着生基質表面から離脱せず、着生基質表面に確実に留まるようにするには、遊走子や卵の全体が完全に取り込まれるような厚さの境界層が存在する必要があるからである。着生基質表面の境界層は流動性が低い海水層であり、その内部に完全に取り込まれた遊走子や卵は、着生するまでの間にそこに留まる確率が非常に高くなる。これに対して、境界層の厚さが上記（２）式を満足しないと、遊走子や卵は境界層外の海水流の影響を受けて、着生基質表面から離脱する確率が高まる。
また、遊走子や卵の取り込みが確実に行われるという観点からは、境界層は遊走子や卵の直径Ｄに対して十分に大きい厚さを有すること、例えば、δ≧２Ｄ、さらにはδ≧３Ｄというような十分な厚さを有することが好ましい。
【００１４】
図２は、上記（１）式で規定される境界層の厚さδを示している。ここで、上記（１）式自体は境界層厚さを求めるための広く知られた式であるが、ｘを海水の流れ方向における着生基質上部面の長さの１／２としたのは、少なくとも着生基質上部面の半分に（２）式を満足する境界層を形成させるためである。
【００１５】
本発明により着生基質表面に着生・生育させるべき海中生物の代表例としては、海藻、珊瑚、貝類、フジツボ類、ゴカイ類などがあるが、これらに限定されない。海藻として対象となるのは主に岩礁性藻場を形成する海藻類であり、例えば、マコンブ、アラメ、カジメ、ワカメ等のコンブ目；アカモク、ヤツマタモク、ノコギリモク等のホンダワラ類；マクサ（テングサ）；アナアオサなどが挙げられる。
【００１６】
海藻は、その種類によって親個体から海中に放出される生殖細胞の種類や大きさが異なる。すなわち、アラメ、カジメ、コンブ等のコンブ目では、胞子体（親個体）から長径約５μｍ程度の遊走子が海中に放出され、この遊走子が基質に着生して雌雄の配偶体へと成長し、その雌配偶体で作られた卵が受精することにより幼体、胞子体へと成長する。したがって、この種の海藻を着生基質に着生・生育させる場合には、上記（２）式を満足する境界層厚さδは、海藻の種類に応じて５μｍ以上の厚さとする必要がある。
【００１７】
一方、ホンダワラ類では、胞子体（親個体）から直径約２００〜３００μｍ程度の卵が海中に放出されて海中で受精し、その受精卵が基質に着生して幼体、胞子体へと成長する。したがって、この種の海藻を着生基質に着生・生育させる場合には、上記（２）式を満足する境界層厚さδは、海藻の種類に応じて２００〜３００μｍ以上の厚さとする必要がある。
さらに、珊瑚の場合には、親個体から放出された卵（直径約５００〜７００μｍ）が海中で受精し、その受精卵から長径約２ｍｍ弱程度の幼生（プラヌラ幼生）が生まれ、この幼生が基質に着生（定着）して親個体へと成長する。したがって、珊瑚を着生基質に着生（定着）・生育させる場合には、上記（２）式を満足する境界層厚さδは、珊瑚の種類に応じて２ｍｍ以上の厚さとする必要がある。
【００１８】
上記（１）式で規定される境界層の厚さを制御するための制御因子は、着生基質の設置場所における海水の最大流速Ｕ_０であり、したがって、海水の最大流速Ｕ_０が上記（２）式を満足する境界層厚さδが得られるような値となる場所を着生基質の設置場所として選定するか、或いは着生基質の設置場所における海水の最大流速Ｕ_０を上記（２）式を満足する境界層厚さδが得られるような流速に人工的に制御すればよい。後者の場合には、例えば、設置した着生基質又は着生基質群の周囲に海水流の抵抗となる抵抗体（例えば、板状の抵抗体）を設ける、着生基質又は着生基質群を海水流の抵抗となる通水性のある被覆材で覆う等の方法を採ることができる。
なお、本発明は海だけでなく、湖沼や川などの淡水或いは汽水域での着生基質の設置にも適用できる。
【００１９】
以下、本発明の好ましい条件について説明する。
先に述べたように、一般のコンクリートのｐＨは略１２であり、これを着生基質とした場合の境界層のｐＨも略１２となり、この境界層は遊走子や卵が極めて着生・生育しにくい環境となる。さらに、コンクリートは未炭酸化Ｃａを多量に含んでいるため、これを着生基質として水中に設置した場合、表層に水酸化カルシウムが生成して境界層内にＣａイオンが溶出し、このＣａイオンは境界層内の炭酸ガスと反応して炭酸カルシウムを生成する。この結果、境界層内で遊走子や卵の着生・生育（光合成）に必要な炭酸ガスが不足し、この面でも遊走子や卵の着生・生育が阻害されるとともに、生成した炭酸カルシウムが境界層内の遊走子や卵、基質面に付着することにより、遊走子や卵の着生・生育に悪影響を及ぼす。また、コンクリートの表層に生成した水酸化カルシウムの層は、Ｃａイオンの溶出などによって物理的にも不安定である。したがって、本発明の着生基質としては、一般のコンクリートは適さない。
【００２０】
本発明で用いる着生基質としては、カルシウム成分として実質的に炭酸カルシウムのみを含む（すなわち、不可避的に含まれる未炭酸化Ｃａを除くカルシウム成分の全量が炭酸カルシウムからなる）、ｐＨ１０以下（好ましくは、ｐＨ７．５〜９．５）の基質が特に好ましい。このような着生基質としては、例えば、粉粒状原料を適当なバインダー成分でブロック化したブロック体などが挙げられるが、これに限定されるものではない。このような着生基質を用いることにより、境界層のｐＨを１０以下（好ましくは７．５〜９．５）に維持できるとともに、基質からＣａイオンが溶出することもないので、境界層内の炭酸ガス濃度も遊走子や卵の生育に適したレベルに維持することができる。また、基質表面で新たに炭酸カルシウムが生成することもなく、しかも着生基質が元々含有している炭酸カルシウムは物理的に安定しているため、着生・生育しようとする遊走子や卵の保護にも有効である。
【００２１】
本発明によれば、基質に着生促進のための特別な処理や加工を施さなくても、着生基質に海藻や珊瑚等を効果的に着生・生育させることができるが、例えば、基質面に着生促進のための処理（例えば、着生促進物質の塗布や添付等）や加工（例えば、凹凸加工や溝加工等）を施したり、基質に着生促進物質を添加したりすることを排除するものではない。
以上述べたような本発明法により設置された着生基質は、海藻や珊瑚等のような水中生物を短期間で効果的に着生・生育させることができ、このため短期間で藻場や珊瑚礁等の造成・修復を行うことができる。
【００２２】
【発明の効果】
以上述べた本発明によれば、基質面に着生促進のための特別な処理や加工を施したり、基質に着生促進物質を添加したりしなくても、水中に設置した着生基質に海藻類や珊瑚等を効果的に着生・生育させることができる。
【図面の簡単な説明】
【図１】ｐＨ１０の基質とｐＨ１２の基質を水中に設置した場合似おける、基質−境界層−境界層外のｐＨの遷移の概略を示す説明図
【図２】本発明の（１）式で規定される境界層厚さδを示す説明図[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method of placing an epiphytic substrate (base) on which aquatic organisms such as seaweed and coral to grow on underwater, and can effectively grow seaweed and coral on the substrate. In particular, the present invention provides a method suitable for creating and restoring seaweed beds (algae), coral reefs, and the like.
[0002]
[Prior art]
Seaweed beds where seaweeds such as Honda straw, alame, squid, and kelp are a place of production of marine animals and plants in coastal waters, habitats of useful seafood and seaweeds, spawning grounds of seafood, nursery of fry, It can be said that it is an indispensable place as a feeding ground. In recent years, nitrogen and phosphorus in seawater have been removed by being taken up by seaweed or by other organisms through the food chain in the seaweed bed, and suspended substances settled in the seaweed bed and removed from the water. Attention is also being paid to the water purification effect of seaweed beds.
[0003]
However, in recent years, seaweed beds have been rapidly disappearing and declining due to the effects of coastal land reclamation and seawater pollution. In recent years, especially in many coastal waters, the so-called "iso-yake" phenomenon has occurred, Has become a problem. For this reason, in recent years, measures (seaweed bed creation) for restoring disappeared or decayed seaweed beds have been taken in various places.
One of the conventional methods of seaweed bed creation is to install a substrate (usually a concrete block, etc.) for growing seaweed at the place where the seaweed bed is to be created, and use this substrate as a seed or seedling for seaweed. There is a method of transplanting algae and performing maintenance for seaweed cultivation as necessary. However, this method requires labor and cost for transplanting seeds and seedlings to the substrate and maintenance after setting the substrate, and is not suitable for large-scale formation of a seaweed bed. Therefore, as a basic method of seaweed bed creation, it is necessary to install the substrate as it is without transplanting seeds and seedlings, and to set up and grow seaweed without maintenance after installation. It is thought that there is.
[0004]
[Problems to be solved by the invention]
Conventionally, concrete blocks have been widely used as an epiphytic substrate installed at a seaweed bed creation site in terms of ease of production, stability in the sea, production costs, and the like. However, there is a problem that even if a concrete block is simply set on the seabed as an epidermal substrate, a sufficiently satisfactory amount of seaweed cannot be epiphysed and grown. Therefore, countermeasures for promoting seaweed formation, such as forming irregularities or grooves on the substrate surface of the block, applying or attaching an adhesion promoting substance, or adding an adhesion promoting substance to the substrate (for example, Patent Document 1, Patent Literature 2 and Non-Patent Literature 1) have also been tried, but their effects are not always clear, and special processing or treatment is applied to the substrate surface for the purpose of promoting the growth of the substrate, or the growth of the substrate is promoted. The addition of a substance has a problem in terms of the cost of creating a seaweed bed.
[0005]
[Patent Document 1]
JP 2001-275506 A [Patent Document 2]
Japanese Patent Application Laid-Open No. 2002-45080 [Non-Patent Document 1]
"The 54th Annual Meeting of the Cement Technology Congress 2000" p. 410-411
[0006]
Therefore, an object of the present invention is to provide a seaweed to an epidermal substrate placed in water without applying a special treatment or processing to the substrate surface to promote the growth of the substrate or adding an epidermal promoting substance to the substrate. It is an object of the present invention to provide a method of installing an epiphytic substrate capable of effectively establishing and growing underwater organisms such as corals and corals.
[0007]
[Means for Solving the Problems]
The present inventors have studied on various conditions for zoospores and eggs such as seaweed to settle on the surface of an epithelial substrate installed in the sea and grow them into juveniles. Focusing on the boundary layer, we conducted detailed experiments and examined the effects of this boundary layer on the formation and growth of zoospores and eggs such as seaweed. As a result, it was found that the microenvironment area (boundary layer) of seawater existing on the surface of the epidermal substrate was greatly involved in the establishment and growth of zoospores and eggs of seaweed. In other words, the breeding form of seaweed is that zoospores and eggs released from the spore body (parent individual) float in the seawater, reach the substrate, settle on the surface, and then to the larva and further to the spore body Although it grows, if the zoospore or egg reaches the surface of the substrate and the boundary layer of an appropriate thickness is formed on the substrate surface, the zoospore or egg is taken into the boundary layer (ie, This boundary layer becomes an environment (area) where zoospores and eggs set and grow. Since the water quality of the boundary layer is largely controlled by the composition and properties of the substrate itself, if the water quality environment of the boundary layer is suitable for the zoospores and eggs, The zoospores and eggs in the layer will appropriately settle and grow on the substrate surface. In other words, in order to properly grow zoospores and eggs on the surface of the substrate and to grow to the juveniles, the zoospores and eggs have an appropriate thickness that can take in the zoospores and eggs that have reached the substrate, It was found that it was necessary to form a boundary layer having a water environment suitable for growth on the substrate surface. As a result of further study on a method for forming such a boundary layer, a substrate having a pH below a predetermined level is used as a substrate, and the substrate is used for zoospores, eggs, etc. of organisms to be established. It has been found that it is necessary to install in a submarine environment where a boundary layer having a thickness greater than the diameter of is formed.
[0008]
The present invention has been made based on such findings, and the features thereof are as follows.
[1] In a method of placing an epiphytic substrate for living organisms that grow on the substrate in water by placing it in water, the epiphytic substrate having a pH of 10 or less is placed on the upper surface of the epidermal substrate defined by the following formula (1). Of the zoospore, egg or larva of the organism to be established and grown on the surface of the epithelial substrate (however, if the zoospore, egg or larva is not spherical, its major diameter is A method for installing an epiphytic substrate for aquatic organisms, wherein the substrate is installed in water so as to satisfy the following condition (2) in relation to (1).
(Equation 2)

[0009]
[2] The method for setting an epiphytic substrate for aquatic organisms according to the above-mentioned [1], wherein the epithelial substrate has a pH of 7.5 to 9.5.
[3] In the installation method according to the above [1] or [2], the organism to be formed and grown on the surface of the substrate is one or more species selected from seaweed, coral, shellfish, barnacles, and moss. A method for setting an epiphytic substrate for aquatic organisms, characterized in that:
[4] The method according to any one of [1] to [3], wherein the epithelial substrate contains substantially only calcium carbonate as a calcium component. .
[5] An epiphytic substrate for aquatic organisms, which is installed in water by the method of any one of [1] to [4].
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the details and preferred embodiments of the method for installing an epiphytic substrate for aquatic organisms according to the present invention will be described. In the following, a case where the epidermal substrate is installed in the sea will be described as an example.
The present invention provides a microenvironment region in which zoospores and eggs such as seaweed can be taken in on the surface of an epithelial substrate and these can be appropriately established and grown when the epithelial substrate is placed in the sea, that is, a specific thickness. The aim is to form a boundary layer with water quality.
[0011]
Therefore, in the present invention, first, a substrate having a pH of 10 or less is used as an epidermal substrate.
Normal seawater has a weak alkaline pH of about 7.8 to 8.4, but if the pH exceeds 10, the formation and growth of zoospores and eggs are significantly inhibited. Here, the boundary layer formed on the surface of the epithelial substrate is a seawater layer having a small thickness in contact with the substrate and having a low fluidity. Therefore, its pH is substantially the same as the pH of the substrate itself. In order to adjust the pH to 10 or less, which is suitable for zoospores and egg growth, it is necessary to use an epiphytic substrate having a pH of 10 or less. FIG. 1 schematically shows the transition of the pH between the substrate, the boundary layer, and the outside of the boundary layer for the substrate at pH 10 and the substrate at pH 12. The pH of ordinary concrete is approximately 12, and therefore, the boundary layer formed on the surface of the concrete substrate is also approximately pH 12, and this boundary layer can be said to be an environment in which zoospores and eggs are extremely difficult to set and grow. Further, the more preferable pH of the epidermal substrate used in the present invention is 7.5 to 9.5, and the pH of the boundary layer is also substantially the same.
[0012]
Furthermore, as a condition of the boundary layer formed on the surface of the epithelial substrate, it is necessary that the thickness of the boundary layer is larger than the diameter of zoospores, eggs, etc. of the organisms to be established and grown on the substrate. Specifically, the thickness δ of the boundary layer formed on the upper surface of the epithelial substrate, which is defined by the following formula (1), is equal to the zoospore, egg, or In order to satisfy the condition of the following formula (2) in relation to the diameter D of the larva, it is necessary to place the epiphytic substrate in the sea. In addition, as described later, since the thickness of the boundary layer is defined as a condition for completely incorporating the zoospores, eggs, etc., when the zoospores, eggs, or larvae are not spherical, their major diameters And the above diameter D.
[Equation 3]

[0013]
In the present invention, the thickness δ of the boundary layer is defined as in the above equation (2) because zoospores, eggs, and the like that reach the surface of the epiphytic substrate along with the flow of seawater again ride on the flow of seawater. In order to ensure that the zoospores and eggs are completely incorporated, there must be a boundary layer to ensure that they do not detach from the surface of the epithelial substrate and remain on the surface of the epithelial substrate. is there. The boundary layer on the surface of the epithelial substrate is a seawater layer with low fluidity, and zoospores and eggs that have been completely incorporated therein will have a very high probability of staying there before they settle. On the other hand, if the thickness of the boundary layer does not satisfy the above equation (2), the probability of the zoospores and eggs detaching from the surface of the epiphytic substrate under the influence of the seawater flow outside the boundary layer increases.
In addition, from the viewpoint that zoospores and eggs are taken up reliably, the boundary layer should have a thickness that is sufficiently large with respect to the diameter D of the zoospores and eggs, for example, δ ≧ 2D, and furthermore, δ ≧ It is preferable to have a sufficient thickness such as 3D.
[0014]
FIG. 2 shows the thickness δ of the boundary layer defined by the above equation (1). Here, the above equation (1) itself is a widely known equation for calculating the thickness of the boundary layer, but x is set to の of the length of the upper surface of the epiphytic substrate in the seawater flow direction. This is because a boundary layer satisfying the expression (2) is formed on at least half of the upper surface of the substrate.
[0015]
Representative examples of marine organisms to be formed and grown on the surface of the epithelial substrate according to the present invention include, but are not limited to, seaweed, coral, shellfish, barnacles, and moss. The seaweeds are mainly seaweeds forming rocky seaweed beds. For example, the seaweeds such as makombu, alame, swordfish, seaweed; and the like, such as the red seaweed, the red seaweed, the sawfish, etc .; Anaoasa and the like.
[0016]
The type and size of germ cells released into the sea from a parent individual vary depending on the type of seaweed. In other words, in the order of the kelp, such as larvae, squid, and kelp, spores (parent individuals) release zoospores having a major axis of about 5 μm into the sea, and the zoospores attach to the substrate and grow into male and female gametes. The fertilized egg produced by the female gametophyte grows into a larva and a sporophyte. Therefore, when this type of seaweed is to be formed and grown on an epithelial substrate, the boundary layer thickness δ that satisfies the above equation (2) needs to be 5 μm or more depending on the type of seaweed. .
[0017]
On the other hand, in the straws, eggs having a diameter of about 200 to 300 μm are released from the sporophyte (parent individual) into the sea and fertilized in the sea, and the fertilized eggs settle on the substrate and grow into larvae and sporophytes. . Therefore, when this type of seaweed is to be formed on an epithelial substrate, the boundary layer thickness δ that satisfies the above equation (2) needs to be 200 to 300 μm or more depending on the type of seaweed. There is.
Furthermore, in the case of coral, eggs (approximately 500-700 μm in diameter) released from a parent individual are fertilized in the sea, and larvae (planula larvae) having a major axis of about 2 mm or less are produced from the fertilized eggs, and these larvae are used as substrates. And develop into a parent individual. Therefore, when the coral is to be established (fixed) and grown on the epithelial substrate, the boundary layer thickness δ that satisfies the above equation (2) needs to be 2 mm or more depending on the type of coral. .
[0018]
Regulator for controlling the thickness of the boundary layer as defined in the above (1) is the maximum flow velocity U ₀ of the seawater at the installation location of the epiphytic substrate, therefore, the maximum flow velocity U ₀ of the seawater above ( Either a location where the boundary layer thickness δ that satisfies the expression (2) is obtained is selected as the location of the epidermal substrate, or the maximum flow rate U0 of seawater at the location of the epidermal substrate is determined by the above _equation (2). It suffices to artificially control the flow velocity so as to obtain the boundary layer thickness δ satisfying the expression (3). In the latter case, for example, a resistor (for example, a plate-shaped resistor) that provides resistance to seawater flow is provided around the set epiphytic substrate or epiphytic substrate group. For example, a method of covering with a water-permeable coating material that is resistant to seawater flow can be employed.
The present invention can be applied not only to the sea but also to the installation of an epiphytic substrate in freshwater or brackish water such as a lake or a river.
[0019]
Hereinafter, preferable conditions of the present invention will be described.
As described above, the pH of general concrete is approximately 12, and the pH of the boundary layer when using it as an epithelial substrate is also approximately 12. This zoospore or egg is extremely apt to grow and grow on this boundary layer. It is an environment that is difficult to do. Furthermore, since concrete contains a large amount of uncarbonated Ca, when it is placed in water as an epithelial substrate, calcium hydroxide is generated in the surface layer and Ca ions are eluted in the boundary layer, and this Ca ion Reacts with carbon dioxide in the boundary layer to produce calcium carbonate. As a result, there is a shortage of carbon dioxide necessary for the formation and growth (photosynthesis) of zoospores and eggs in the boundary layer. Adheres to zoospores, eggs, and the substrate surface in the boundary layer, which adversely affects the formation and growth of zoospores and eggs. The layer of calcium hydroxide formed on the surface of concrete is physically unstable due to elution of Ca ions and the like. Therefore, general concrete is not suitable as the epiphytic substrate of the present invention.
[0020]
The epidermal substrate used in the present invention contains substantially only calcium carbonate as a calcium component (that is, the total amount of calcium components excluding unavoidable uncarbonated Ca is composed of calcium carbonate), and has a pH of 10 or less (preferably). Is particularly preferably a substrate having a pH of 7.5 to 9.5). Examples of such an epithelial substrate include, but are not limited to, a block obtained by blocking a granular material with an appropriate binder component. By using such an epithelial substrate, the pH of the boundary layer can be maintained at 10 or less (preferably 7.5 to 9.5), and Ca ions are not eluted from the substrate. The carbon dioxide concentration can also be maintained at a level suitable for the growth of zoospores and eggs. In addition, no new calcium carbonate is generated on the substrate surface, and the calcium carbonate originally contained in the epithelial substrate is physically stable. It is also effective for protection.
[0021]
According to the present invention, it is possible to effectively grow and grow seaweed, coral, etc. on the substrate, without performing special treatment or processing for promoting the substrate on the substrate. Subjecting the surface to a treatment for accelerating the formation (for example, applying or attaching an accelerating substance), processing (for example, embossing or grooving), or adding an accelerating substance to the substrate; Does not exclude.
The epithelial substrate provided by the method of the present invention as described above can effectively establish and grow aquatic organisms such as seaweed and coral in a short period of time. Construction and restoration of coral reefs can be performed.
[0022]
【The invention's effect】
According to the present invention described above, the substrate surface is not subjected to a special treatment or processing for promoting the formation of an epithelium, and the addition of the substance for promoting the formation of the substrate does not require the substrate to be placed in water. Seaweeds and corals can be effectively set and grown.
[Brief description of the drawings]
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view schematically showing a transition of pH between a substrate, a boundary layer, and a boundary layer outside when a substrate having a pH of 10 and a substrate having a pH of 12 are placed in water. FIG. Explanatory drawing showing the prescribed boundary layer thickness δ

Claims

In a method of placing an epithelial substrate for living organisms that grow on the substrate in the water,
A zoospore of an organism to be formed and grown on the surface of an epithelial substrate having a thickness δ of a boundary layer formed on the upper surface of the epithelial substrate defined by the following formula (1) and having a pH of 10 or less. And the diameter of the egg or larva D (or the longest diameter if the zoospore, egg or larva is not spherical), and is installed in water so as to satisfy the condition of the following formula (2). How to set epiphytic substrates for living organisms.

The method of claim 1, wherein the epiphytic substrate has a pH of 7.5 to 9.5.

The aquatic organism according to claim 1 or 2, wherein the organism to be established and grown on the surface of the epiphytic substrate is at least one selected from seaweed, coral, shellfish, barnacles, and moss. How to set the epidermal substrate for use.

The method according to claim 1, 2 or 3, wherein the epidermal substrate contains substantially only calcium carbonate as a calcium component.

An epiphytic substrate for aquatic organisms installed in water according to the method of claim 1, 2, 3 or 4.