Close-up of the edge of a village pond in Tholthorpe, Yorkshire, England, showing the effects of Euglena sanguinea. Encysted Euglena cells float on the water's surface; when the red carotenoid pigments are at the cell's surface, the euglena cells and the bloom are red. When exposed to the sun, the red pigment migrates to the cell's center, turning the cells and thus the bloom green. See 3Q2019 for the red bloom.