Carbon wells, sources of oxygen but also, potentially, renewable energy ... Microalgae should be studied more.
Discreet, because microscopic compared to algae that is easily observed with the naked eye on rocky coasts, microalgae can form so-called efflorescences - or "bloom", in English language. What is it about ? The phenomenon concerns more particularly the species living in aquatic environment. When one of them finds in its natural environment very favorable conditions, it multiplies exponentially, to eliminate the others. It is easily perceived by observing the surface of the body of water, whether it is the ocean, the sea or a lake: it changes color, from blue to yellow or red , Depending on the species.
From these observations came the idea of reproducing the phenomenon in a confined environment, while controlling it. Initially, the aim was to produce microalgae "fodder", which are used to feed molluscs - more precisely, their juveniles, in other words the young. This is particularly the approach adopted in hatcheries on the French Atlantic coast, where naturally occurring species are grown in the natural environment. However, in sunny and warmer regions and sometimes for many years, species of economic interest for the agri-food or medical sector are produced (in ponds or photobioreactors). Among other things, these species produce pigments with antioxidant properties.
Oils and oil
The recent demand for omega-3 fatty acids, polyunsaturated fatty acids whose health benefits have been praised for some years, could encourage these crops. These omega-3s are essentially derived from fatty fish living in cold water and now threatened with overfishing. It has long been known that certain microalgae are capable of synthesizing them. It is therefore sufficient to control their culture so that they become a renewable source of omega-3. This is done in the Pays de la Loire, where a diatom - Odontella aurita - is grown in open tanks and has been marketed for several years as a dietary supplement rich in manga-3 and silica. But the interest of microalgae is not only food ...
By replacing the usual fossil energies (oil, coal) with intensively grown microalgae, a new source of renewable energy could be available. And in the near future, the oil that can be extracted from these particular plants would thus be able to solve the problems of fuel supply at the global level. It should be noted that the engine invented by Rudolf Diesel originally operated with vegetable oil: oil tankers imposed petroleum-derived gas oil. However, on diesel-powered vehicles that are a little older, it is easy to use all kinds of oils as fuel. So why not an oil from microalgae?
A carbon trap
In the United States, a few years ago, a colleague responsible, as I was with a microalgae research laboratory, operated his vehicle with oil produced by his students. But in France, it's ... forbidden! Although I owned a vehicle of the same type, I did not venture to experiment. In conclusion, it should be added that 30 to 40% of the carbon dioxide released into the atmosphere has always been naturally fixed by the enormous biomass constituted by marine phytoplankton, that is to say, marine microalgae. This is not very surprising. Like all plants, algae use carbon dioxide during photosynthesis to make their own material (and, incidentally, release oxygen). Moreover, the oceans account for 70% of the world's surface. Finally, phytoplankton is generally present over several tens of meters from the surface. In any case, microalgae have been participating for thousands of years in limiting the greenhouse effect on our planet.
Sources of nutrients beneficial to our health, carbon dioxide sinks and sources of oxygen, potential sources of renewable energy that could be useful to transport both terrestrial (biofuel) and air (biokerosene), these particular plants do not Are not yet sufficiently intensively grown. At least that's my opinion. For if these cultures accelerated, they would otherwise save the planet, at least to prevent it from deteriorating further. For the well-being of our children, our grandchildren and future generations ...
By: GÉRARD TREMBLIN*, THE CONVERSATION FRANCE: Professor of Plant Biology Emeritus at the University of Maine.
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