Transcript:

Algae BloomsAmbience: OceanThere are many types of algae found in bodies of water around the world. Sometimes they experience spurts of growth called algal blooms, and the effects can be devastating. I'm Jim Metzner and this is the Pulse of the Planet.Nealson: The algae normally are in small numbers in the ocean and don't bother anybody, but occasionally conditions get right where the algae will go from a few cells per milliliter to thousands of cells per milliliter. You can see this by the color of the water. Often it turns a reddish color. Under those conditions, the algae produce enough toxin that can really become a nuisance and an economic disaster.Ken Nealson is a Wrigley professor in the Department of Earth and Biological Sciences at the University of Southern California.Nealson: That algal bloom will always crash because they run out of enough nutrients and that part of the ocean, for a brief time, all the bacteria will eat the algae and use up all the oxygen. And then the fish either have to move out or they'll die from lack of oxygen. We don't really understand what cause an algal bloom. Which nutrients will allow that to happen and how they build up and how you know that it is happening. What would be really valuable would be to have an early warning system so that you could see if something was going on. And if you knew what was causing it, then you could try to stop it. They happen usually near the shorelines, which makes us think it's connected somehow with the supply of nutrients, but they happen all over the world. We can see them off the coast of Africa; we can see them off the coast of India. Often we'll have an algal bloom right in Los Angeles harbor. One of the challenges facing researchers is that there may well be multiple causes for algae blooms. I'm Jim Metzner and this is the Pulse of the Planet.