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An inexhaustible resource could make it possible to fight against the effects of climate change: seaweed captures CO2, is a source of human and animal food, and even produces electricity.
They were there long before us, and we owe them everything. ” Algae are the first complex living organisms to exist on earth, and so all the rest of life was organized around algae “, explains Vincent Doumeizel, algae activist. Adviser on the oceans at the UN, he leads the World Coalition of Algae Stakeholders. It is in particular thanks to algae that humans are so intelligent: ” It is now proven that it is a massive ingestion over thousands of generations of polyunsaturated fatty acids found only in algae and fish that has allowed our brains to be so big, not mammoth or other meat protein. »
Algae to light a light bulb
Algae have superpowers; in particular, they have the capacity to produce electricity, as described this month by Vincent Doumeizel in the review Latitude Mer (editions of Ecuador). Thanks to photosynthesis, that is to say the transformation, by plants, of sunlight into energy, this year we were able to light a light bulb. ” It has long been known that microalgae during photosynthesis produce electricity – an exchange of electrons takes place, continues Vincent Doumeizel. By placing electrodes on a green algae, the ulvas, which are the most productive, we managed to light a light bulb. »
Water conducts electricity
But then the trees and all the plants, which do photosynthesis, could they also provide us with electricity? « It’s air around terrestrial plants, so we couldn’t harvest the electricity, says the author of The seaweed revolution (editions of Ecuador). Electricity is lost in the air which is not conductive. Since the water is conductive, the electricity produced by the macro-algae can be recovered. »
An ecological weapon
The material is inexhaustible, but it will surely take decades before the technologies are developed to be able to exploit this very green energy. But already, the algae are full of resources in the face of the ecological emergency. ” Algae absorb as much greenhouse gases as the Amazon today, recalls Vincent Doumeizel. They provide over 10% of the diet in Japan with incredible benefits. It is also a source of animal feed, of natural biostimulants which could replace fertilizers. All of this could provide a source of income for coastal populations who are piling up in misery while the resource is there and just waiting to be cultivated. » What about seaweed fields at the edge of the oceans? After offshore wind farms, there will soon be seaweed fields.
► The question of the week
Why does it smell so good when rain starts falling when it’s hot?
This smell of wet earth, of oncoming rain, does not come from the earth, nor from the rain, but from the plants which produce petrichor, a kind of oil which protects the leaves from drought, and which is released on contact water drops. Another phenomenon is associated with it, the release, by the rain, of a gas produced by bacteria contained in the earth. And if this perfume is so pleasant to us, it is because, in humans, the olfactory memory is the most developed; it is the memory, the signal, since the dawn of time, of the end of the drought, of the return of life.