By algae, we mean both prokaryotic organisms (blue algae or cyanobacteria) and eukaryotic organisms. Green and red algae belong to the green line, brown algae from the coasts or Phéophycées and Diatoms belong to the Stramenopiles.

A distinction is made between microalgae, which are single-celled or small in size, and macroalgae, which are larger in size.

Many algae are of great interest to the food industry because they are rich in phycocolloids, complex polysaccharides with thickening, gelling and stabilizing properties.

In food, the most commonly used phycocolloids are carrageenans. Extracted from red seaweed, they are used as additives in products as varied as ice cream, yoghurts, but also fish rillettes, sausages or prepared meat dishes.

To a lesser extent, alginates from brown algae and agar-agar from red algae are also used, particularly for molecular cooking preparations.

Finally, some sea weed can be used directly and can be found in many Asian dishes such as sushi.

In addition to food, algae also have properties more related to the medical field. Phycocolloids are not digestible and can be assimilated to plant fibres. Algae are also rich in iodine.

The film was shot at the Talence Botanical Garden, which is part of the University of Bordeaux.