Airdate: Oct 08, 2008
Scientist: Dave Whitall - (pronounced "white-all")
Off the coast of Louisiana there's a region of ocean the size of the state of New Jersey that's virtually devoid of life.
Dead Zone - Solutions
Music; Ambience: Waves, gentle
It's called "The Dead Zone" - a large stretch of ocean just off the coast of Louisiana. Virtually nothing lives or grows here because of the lack of oxygen in the water. I'm Jim Metzner and this is the Pulse of the Planet. There are lots of other bodies of water with low oxygen around the world, but none quite so large as the Dead Zone. Excessive amounts of nutrients in the water cause microscopic plants to bloom, die and use up all the oxygen.
Whitall: Nutrients come from a variety of sources, especially nitrogen, and it really comes from a lot of different sources within the landscape.
Dr. Dave Whitall is with the National Oceanic and Atmospheric Administration's Center for Coastal Monitoring and Assessment.
Whitall: The primary source of nitrogen in the Gulf of Mexico watershed is agriculture, so runoff from chemical fertilizers used to grow crops as well as from manure from animal production. But there's also other sources of nitrogen, such as human waste that gets processed through wastewater treatment plants. There's a component of air pollution, so our car exhaust and our power plant exhaust eventually come back down to Earth. There's nitrogen involved in that. So, it really is a multiple source pollutant that makes management of this problem a lot more difficult than if it was just coming from one source. For example, agriculture, one solution would be just to apply less chemical fertilizer in the watershed. Of course, that's going to have impacts in terms of the productivity of the area. You can't, obviously, stop using fertilizer, or your crops won't grow. But there's certain management practices, such as making sure to apply your fertilizer at the correct time of year. There's different crop practices in terms of when you plow your fields that can reduce the amount of nitrogen that make it into the river. There's really a variety of ways that you can reduce nitrogen and phosphorous, and as those nutrients go down, we would also expect the dead zone to decrease in size.
We'll hear more on the Dead Zone in future programs. Pulse of the Planet is made possible by the National Science Foundation. I'm Jim Metzner.