These beautiful red microalgae are called Euglena sanguinea and are found all over the world in eutrophic freshwater habitats. They remind Chloé of blood oranges, they even look like they have pulps! Along with Euglena sanguinea there were lots of other microalgae like the yellow flower-like Synura, some dinoflagellates and lots of cool rotifers I’ll be posting about soon! What is so special about Euglena sanguinea is that it has the ability to turn from green to red in only 8 minutes and from red to green in about 20 minutes! The accumulation of red carotenoid astaxanthin pigments in the cell is caused by chronic environmental stress conditions such as high UV radiations.