Algal blooms may be caused by overfishing

Scientists have recently determined that one of the main reasons why algal blooms spread across the surface of lakes, rivers, seas and oceans is the fact that top predatory fish in these ecosystems are being hunted. The animals usually keep algae in check, but, as they disappear, the organisms spawn out of control. They are extremely dangerous because they have the ability to block sunlight from entering the waters below their levels, creating havoc in the trophic chain, and destabilizing the ecosystems. The new find adds to different studies, which show that human chemicals, such as nitrogenous fertilizers and detergents, also play an important part in promoting excessive algal growth. The study that showed predatory fish-stock depletion to be a cause of the blooms was conducted in the Baltic Sea, by researchers from the University of Groningen, in the Netherlands. The group was led by expert Britas Klemens Eriksson, who first observed that the blooms tended to appear in areas where predatory-fish stocks had been depleted, or about to be so, Nature News reports…. Read Full Article