Dead Zone – Causes

Dead Zone – Causes

Ambience: Waves, gentle

JM: Since the 1980’s, scientists have been observing an area in the waters off the coast of Louisiana where hardly any thing lives or grows. They call it – The Dead Zone. I’m Jim Metzner, and this is the Pulse of the Planet.

Whitall: The area that we’re talking about off the coast of Louisiana is a very large area. It ranges in size from over 5,000 square miles to over 8,000 square miles. And just to give you an idea, that’s about the size of the state of New Jersey. This is an offshore area, so we’re not talking about something that you could see from the beach. We’re talking about something that’s miles offshore.

Dr. Dave Whitall is with the National Oceanic and Atmospheric Administration’s Center for Coastal Monitoring and Assessment. He says what creates the Dead Zone is a lack of oxygen in the water.

Whitall: The presence of low oxygen areas is ecologically quite important because any organism that requires oxygen to live can’t survive in an area where there is no oxygen. So any fish either has to leave that area of low oxygen, or it’s gonna die. So this is a very important problem.

Whitall: The Dead Zone is caused by a cascade of events that starts with nutrients in the form of nitrogen and phosphorous coming down the Mississippi River. The nitrogen and phosphorous are critical nutrients for plant growth, including microscopic plants called phytoplankton. When you get a lot of nutrients into the system, the phytoplankton will grow rapidly, or bloom, and when you have these phytoplankton blooms, eventually, when the phytoplankton die, they sink into the bottom waters. And as they get broken down and decomposed, that uses up oxygen. So, essentially, what’s happening is the root cause of the low oxygen is nutrients coming down the Mississippi River, but that’s taken through this biological process of algal blooms and subsequent decomposition.

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.

Dead Zone - Causes

Off the coast of Louisiana there's about 6000 square miles of ocean that're virtually devoid of life.
Air Date:11/18/2015
Scientist:
Transcript:

Dead Zone - Causes

Ambience: Waves, gentle

JM: Since the 1980's, scientists have been observing an area in the waters off the coast of Louisiana where hardly any thing lives or grows. They call it - The Dead Zone. I'm Jim Metzner, and this is the Pulse of the Planet.

Whitall: The area that we're talking about off the coast of Louisiana is a very large area. It ranges in size from over 5,000 square miles to over 8,000 square miles. And just to give you an idea, that's about the size of the state of New Jersey. This is an offshore area, so we're not talking about something that you could see from the beach. We're talking about something that's miles offshore.

Dr. Dave Whitall is with the National Oceanic and Atmospheric Administration's Center for Coastal Monitoring and Assessment. He says what creates the Dead Zone is a lack of oxygen in the water.

Whitall: The presence of low oxygen areas is ecologically quite important because any organism that requires oxygen to live can't survive in an area where there is no oxygen. So any fish either has to leave that area of low oxygen, or it's gonna die. So this is a very important problem.

Whitall: The Dead Zone is caused by a cascade of events that starts with nutrients in the form of nitrogen and phosphorous coming down the Mississippi River. The nitrogen and phosphorous are critical nutrients for plant growth, including microscopic plants called phytoplankton. When you get a lot of nutrients into the system, the phytoplankton will grow rapidly, or bloom, and when you have these phytoplankton blooms, eventually, when the phytoplankton die, they sink into the bottom waters. And as they get broken down and decomposed, that uses up oxygen. So, essentially, what's happening is the root cause of the low oxygen is nutrients coming down the Mississippi River, but that's taken through this biological process of algal blooms and subsequent decomposition.

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.