Tiny and insidious, microalgae are multiplying along our coastlines. Although vital to our survival, some 200 out of 5,000 species studied are harmful to people and ecosystems. As global warming intensifies the problem, our oceans may be growing ever more toxic. The Down to Earth team investigates.
Microalgae tend to be invisible to the naked eye, although occasionally algal blooms can be seen from space as they leave behind a trail of green, orange, brown, or even red sludge. It's a natural phenomenon, says Yoan Le Merrer, a marine scientist at French Institute for Ocean Science (IFREMER), but it's not entirely harmless.
