This brightly colored algae protects 900 animal species and 150 plant species

Animal ? Vegetable? Corallines are one of those creatures that have long disturbed naturalists. It was ultimately Rodolfo A. Philippi, director of the Natural History Museum of Santiago (Chile) who decided in 1837: they were algae. In other words, a marine plant.

In the huge family of red algae, Phymatolithon calcareum worth the detour. Firstly because as an algae, it is one of the rare species not to have a sedentary life, except in its juvenile stage. There, it develops slowly (0.5 mm per year), forming thin limestone crusts on the rocks and shell debris of the seabed, up to 30 m deep.

But when mature, the red algae tending to purple and pink deploys its branches (or thalli) which will detach to form banks of floating, spherical arbuscules with a mineral appearance, similar to coral debris. Because this is the other particularity of the species, it fixes marine minerals with delight. Result ? It is loaded with calcium (up to 80%), magnesium, etc.

By gathering in the form of banks, these mineralized algae form the maërl, an environment offering galleries and hiding places important for marine biodiversity. Nearly 900 animal species and 150 plant species have been listed in maërl, the Breton equivalent of tropical coral.