Cultivation of Algae: Microalgae, Macro algae and more…

The Cultivation of Algae or algae culture, is a sort of aquaculture  that carries out  the cultivation of marine algae species in laboratories. Most of these crops are microalgae, such as phytoplankton and microphytes.

The procces is quite different in the case of macro algae since they are difficult to cultivate, especially because of their large size. Hence, their harvest is carried out directly from the ocean.

Basic Cultivation of Marine Algae

Cultivation of Algae: Microalgae

Microalgae are those organisms that make up phytoplankton ranging from autotrophs, to microflagellates and micro ciliates.

Cultivation of Algea in LaboratoriesThese species provide a high nutritional content for fish, crustaceans and mollusks. They are also quite helpful for handling systems of cultures in laboratories, and producing agar and carrageenan .

In most cases the main reason for cultivating microalgae, is to obtain species in a controlled environment. Another reason, is to expand their  population for commercial, industrial and ecological purposes, as well as to investigate their characteristics, life styles  and to know about the optimal conditions for them to grow.

There are many reasons why laboratories around the world are researching algae. It is considered that they have a potential high value ; especially for the commercial, industrial, technological and pharmaceutical areas. So, the study of these species help us know, the benefits that they offer for human beings and the planet.

Cultivation of Algae in Laboratories

The algae cultures in laboratories fulfill an specific function, which is to know and investigate everything related to a single species. In this sense, the advantages offered are those of studying them in an isolated environment. Experiments in laboratories also allow  a bigger knowledge about the optimal conditions of large-scale cultivation, for commercial and technological uses. So, they also help maximize the growth of the population of the algae studied.

The culture of these species in laboratories,  allows to explore the complex relationships between them and the ideal environment for their reproduction. This is, temperature, pH, light intensity, aeration rate and concentration of nutrients. These are the conditions that ensure that large-scale crops can be made,  with the necessary resources and without generating significant losses.

The models of growth developed in laboratories are a sort of planning tool,  which allows to design and operate optimally photo bioreactors or massive cultures of algae.

Massive Cultivation of Algae: Photo Bioreactors

Photo bioreactors are devices where big amounts of algae can be contained. They are intended to produce the massive growth of  microalgae. These devices are used to produce micro algal biomass in quantities of the order of kilogram per day or tons per year.

Photo bioreactors are designed for a micro alga in particular;  even for an specific application (for example, production of astaxanthin), which doesn´t mean  they can’t be used for several species. Unlike laboratory cultures their goal is not to obtain growth data. Otherwise, the growth models obtained in laboratories are used to design them. The (Photobioreactors)


Cultivation of Algae: Macroalgae

Macroalgae are harvested all over the world reaching  their highest level in Japan and China. Most of them have a high nutritional value, and they are also employed in several industrial processes.

They are highly consumed in Eastern countries. In the rest of the world, they are mostly used as animal food, fertilizers and / or  food additives.

Cultivation Methods

There are some methods of growing macroalgae, that are the most used since ancient times. These methods are mostly used for the reproduction of Red Algae or Rhodophytas, which have a huge commercial and industrial value.

Basket Raft 

It consists of five or more cylindrical bamboo baskets 1 meter long and 17 cm in diameter tied together.

Each basket contains a porous cylinder of strongly buffered mud,  containing 1.5 kg of fertilizer. They have an opening in the upper side of the basket, which makes easy the removal of the fertilizer cylinder. This cylinder must be filled monthly.

A rope is tied on each side of the basket and the juvenile sporophytes adhere by inserting the basal end of the stipe between the strings of the rope.

As the liquid fertilizer seeps from the cylinder, the nutrients are absorbed by the sporophytes.

Basket Raft

One line Tube Raft

It is built by attaching tubes of rubber or bamboo, extreme with extreme. This is  to make a single line of about 60 m long. Every 6 meters along the raft a porous mud jar of 2.8 lt is suspended. which contains fertilizer, at a depth of 1.3 meters.

The juvenile sporophytes similarly adhere at intervals of about 50 cm.The distance between the plants on a string varies between 1.7 to 3.0 cm., while  the length of the string ranges  from 1 to 3 meters. These rafts are placed every 3 or 4 meters between them.

The Two Lines Tube Raft

It is a stair shaped  structure made up  of 1 m long bamboo tubes, which are tied through two strings of 12 to 15 meters in intervals of 1 meter. The tubes are placed in groups of three, with a porous mud cylinder with fertilizers of 2.8 lt, suspended from the middle of the tube of each group.

Ropes with juvenile sporophytes adhere to the tubes, in the same way they do in the other types of rafts .Up to four tube rafts of two lines can be tied every 5 meters.

Two Lines Tubes Rafts

Basic culture method  on Bottoms

It is used only in shallow areas at low tide. The idea is to allow the use of floating rafts, which is called «stone pouring». This method involves placing large stones  of 16 kg of weight into the water, which provides adhesion surface  for zoospores produced naturally.

The stones are placed in rows every 2 meters, and separated from each other every 20 centimeters; resulting in densities of 3800 to 4800 stones per hectare.

In soft bottoms  the stones can be replaced with round baskets made of bamboo or willow branches. Here the spores can adhere to the baskets,  until they are placed in the sea, or may adhere sporophytes with sori.

Cultivation on Bottoms

Finally we invite you to watch this video,  so you can learn how algae are handled in laboratories 

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