In 1971 I worked with researchers at the University of Rochester who were studying the algae blooms that were making a mess of Rochester, New York's Irondequoit Bay. At the time, the limiting factor for algae growth in the lake was phosphorous, and household use of detergents containing phosphates had fueled an algal population boom. Thanks to such research, low-phosphate detergents soon became. I presume the effect on the Bay was salutory, though I graduated and lost track of the researchers.
That was 35 years ago, but apparently we are still learning the same lessons. Please take time to read the long, but worthwhile, article from the Los Angeles Times on the frightening overrowth of toxic algae and other primitive organisms in our oceans.