Microalgae: The Marine Lung of the Earth

Algae are photosynthetic organisms responsible for most of the Earth’s oxygen regeneration by converting light energy and a source of carbon (CO2) into organic matter (biomass). Like terrestrial forests, they remove carbon dioxide from the atmosphere and produce oxygen, which helps regulate the climate. 

In fact, all types of algae produce more than half of the Earth’s oxygen. These algae are found in all aquatic environments, and are an essential part of the life cycle in the marine environment, forming the first link in the food chain. They are also autotrophic, ranging from unicellular known as phytoplankton to multicellular such as seaweed. 

Most algae perform photosynthesis, which uses solar energy to convert carbon dioxide and water into sugars and oxygen.  This process is considered one of the most important vital processes that occur on Earth. Some characteristics of algae differ from terrestrial plants, including the way in which chlorophyll aids in its photosynthesis.

Purification and conservation of stock algal cultures on agar plates
Purification and conservation of stock algal cultures on agar plates, 2023 / Credit: Mohamed Tafraouti.

There are two main classes of algae: macroalgae, which are visible to the naked eye, and microalgae, which are small, single-celled organisms (phytoplankton) found in both fresh and salt water, and moist soil. Therefore, it is considerably one of the most important food sources for small animals in the aquatic environment.

Single-celled phytoplankton appear invisible to the naked eye, but they can be seen in groups, usually in the form of a cloud, especially when they multiply in large quantities, such as what happens in some areas in the seas and oceans.

This can happen in ideal conditions for growth, hence the presence of a suitable temperature and an adequate source of light and vital nutrients like nitrates, phosphorus, potassium and carbon. When these conditions are present, the microscopic algae multiply rapidly and form what is known as an algal bloom. 

Of the many species that make up phytoplankton, some produce toxins called phytotoxins. Those mostly belong to the class Dinophyceae, and are either harmful to marine animals, or a source of pollution, something that is frequently observed in oysters or bivalves that could lead to a ban on their consumption.

Microscopic algae or phytoplankton measures from 2 to 100 micrometers in size, and are essential to marine life because they are at the base of the ocean food chain. They vary from several hundred thousand to several million species, including (47,000) species that have already been classified.

According to Dr. Fatima El Aamri, a researcher at the National Institute of Fisheries Research, microalgae plays an essential and strategic role in the field of aquaculture including mollusks, crustaceans and fish. The main applications of these micro-organisms in aquaculture are related to feeding, where they are used as a single ingredient or as a feeding additive for essential nutrients.

She highlighted that microalgae reduces dependence on antibiotics and drugs often used in conventional aquaculture, which improves the immune system of cultured animals against adverse conditions and pathogens. Commonly used in hatcheries, it produces an extract that inhibits the growth of many types of bacteria.

A researcher in front of her algae culture in her labaratory
Dr. Fatima El Aamri in the laboratory, 2023 / Credit: Mohamed Tafraouti.

They can be particularly useful during rearing of mollusk and shellfish larvae by reducing bacterial contamination during this early and susceptible period.

It has become clear to scientific researchers in Morocco that this botanical richness and new promising biological resource must be invested in for use in many applications in the pharmaceutical, cosmetic and food fields, as well as the production of biofuels and their use in aquaculture, or in the decontamination of gaseous or liquid industrial waste.

The National Institute, as a scientific research institution in the field of marine fishing, has directed its research programs in a way that supports and contributes to the realization of the goals of the strategic plan for the development and competitiveness of the Moroccan marine fishing sector (HALIEUTIS). In terms of aquaculture in general and shellfish breeding in particular, through the establishment of two experimental oyster hatcheries, one in the north of the Kingdom (Mediterranean Sea) and the other in the Gulf of Dakhla in the Atlantic Ocean.

The institute implemented this research project with the aim of developing the offer provided by microalgae products through collecting and isolating samples from local plankton and producing pure cultures to establish a local algae culture bank, which will enable researchers and scientists to evaluate them and study the physical, chemical and genetic characteristics of these strains. This will play an important role in sustainable development, environmental protection and the development of industrial fields in Morocco.

The shellfish farming station was built in the Amsa region, 15 km from the city of Tetouan, within the framework of Moroccan-Japanese cooperation. It is affiliated with the Specialized Centre for Animal Sciences and Engineering of Marine Aquaculture (CSZIAM) of the National Institute for Research in Marine Fisheries (INRH) in M’diq. The station thus provided an important opportunity to develop large-scale bivalve rearing and production techniques that are adapted to local conditions.  This will enable the formation of a scientific database, and prove the technical and economic feasibility of producing local spat bivalves.

Dr. Fatima El Aamri stated that the microalgae designated for bivalve farming at the established station form the basis of the process for producing spat in hatcheries, as they are essential inputs to ensure good preparation of the hatching flocks, and optimal growth of young oysters. Therefore, its good quality mass production is mandatory to improve seeds production process.

There are many different species of microalgae used in shellfish culture, some of which include: Isochrysis sp., Tetraselmis sp., and Chaetoceros sp.

It is inevitable to improve the culturing of algae, as it represents approximately 40% of the total cost of producing spat in hatcheries. This is done by modifying the main factors that affect the growth performance and quality of microalgae cultures (unsaturated fats, proteins, dyes…) which are temperature, salinity, light, and culturing medium.

Many trials are carried out to identify the preferences of each species in production in relation to these factors. This helps to optimize the spat production process and keep production costs at reasonable levels. 

Large-scale algal culture in a warehouse
Large-scale algal culture, Morocco, 2023 / Credit: Mohamed Tafraouti.

The research strategy includes a practical approach based on the development of expertise in microalgae cultivation techniques, from selection and purification to preparation of stock cultures, scaling up and maintenance of large-scale cultures. 

The Shellfish Research and Technology Station works to develop shellfish aquaculture in Morocco by mastering the techniques of shellfish culture and transfer through isolating, selecting, cultivating and improving the mass production of algae species. Thus, developing and perfecting experimental protocols related to rearing bivalve spat culture and then contribute to the development and promotion of shellfish aquaculture in Morocco. 

Dr El Aamri added that research activity in the field of microalgae has increased in recent years, an indication that this sector will be very promising in the future. "We now know better about its potential and importance. Studies estimate that the global market size of microalgae will increase by between 4 to 6% annually.”  

It is noteworthy that Morocco (Akhfnir region) is preparing, in the beginning of 2024, to launch a platform for removing carbon dioxide emitted into the atmosphere to reduce global warming using microalgae.  By establishing a water farm in the middle of the desert with the aim of growing large quantities of algae that will sequester approximately 40,000 tons of carbon dioxide annually. When ready to be harvested, the algae will be filtered from the water, a process that takes between 18 to 30 days. The water is then returned to the ocean.  The microalgae are dried and buried under sand, where the carbon they capture can be permanently stored. This process also contributes to reducing the acidity of water, which negatively affects the climate.

Overall, it can be said that the study of microalgae requires work in various fields and disciplines such as chemistry, biology, engineering, and others.  It is an important research area in many universities and research institutions around the world.

This story was produced with support from Internews' Earth Journalism Network. It was first published in آفاق بيئية (Maroc Environnement) in Arabic on 26 March 2023. It has been translated into English and lightly edited for length and clarity. 

Banner image: Microalgae strains, National Institute of Fisheries Research, Morocco, 2023 / Credit: Mohamed Tafraouti.

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