Quick growth in the population of algae in freshwater or marine ecosystems, as a result of excessive nutrients in the environment. It is usually characterised by changes in the colouration of the sea depending on which species of algae have caused the bloom (red, brown or green). These blooms have a harmful effect on the environment and other species that live in the area: the limit the amount of light that penetrates the water surface, use up all the oxygen in the water and suffocate other organisms, and even produce toxins as a by-product of their metabolism.























































































































