Noctiluca––also known as ‘sea sparkle’––is neither plant nor animal, but a single-celled planktonic organism called a dinoflagellate, which ingests other plankton. With diameters typically of about 0.5mm, dinoflagellates are hard to see with the naked eye. But when they bloom en masse, often due to excess nutrients in the water, they can form a red slime. At night, however, when these tiny organisms are disturbed by movements, such as footsteps or pounding surf, they emit a brilliant blue glow. There is a darker side to bioluminescent blooms that are linked to two environmental problems: they often occur around bays with river mouths, and they’re also more frequent after heavy rainfall. Both suggest pollution and agricultural run-off are leading to a concentration of nutrients such as phosphorus and nitrogen in the water causing populations to explode. According to Australia Geographic,