Light micrograph of Pyrocystis noctiluca(Gr.pyro, fire & Gr. kystis, bladder) marine dinoflagellate alga cells, showing bladder shaped cells with chloroplasts in night position, where the chloroplasts with brownish color are retracted to the cell centre. Pyrocystis in mass reproduction causes a bright bioluminescent ocean glow at night. Culture material of the Culture Collection of Algae at the University of Cologne. Microscopic contrast method: Darkfield contrast. Magnification 45x when printed at 10 centimetres.