Differential interference contrast (DIC) light micrograph of a freshwater alga Gonyostomum sp. Gonyostomum can be a nuisance during summers when they bloom. The surface of the Gonyostomum is covered by small spheres of chloroplasts. Inside the cell, it has various vacuoles. The alga uses flagella to propel itself. Magnification: x1250 when printed at 10 centimetres wide at its longest edge.