More bad news for the world's oceans: Dead zones—areas of bottom waters too oxygen depleted to support most ocean life—are spreading, dotting nearly the entire east and south coasts of the U.S. as well as several west coast river outlets.

According to a new study in Science, the rest of the world fares no better—there are now 405 identified dead zones worldwide, up from 49 in the 1960s—and the world's largest dead zone remains the Baltic Sea, whose bottom waters now lack oxygen year-round.

Click here to see a map of dead zones around the world.

This is no small economic matter. A single low-oxygen event (known scientifically as hypoxia) off the coasts of New York State and New Jersey in 1976 covering a mere 385 square miles (1,000 square kilometers) of seabed ended up costing commercial and recreational fisheries in the region more than $500 million. As it stands, roughly 83,000 tons (75,000 metric tons) of fish and other ocean life are lost to the Chesapeake Bay dead zone each year—enough to feed half the commercial crab catch for a year.

"More than 212,000 metric tons [235,000 tons] of food is lost to hypoxia in the Gulf of Mexico," says marine biologist Robert Diaz of The College of William & Mary in Williamsburg, Va., who surveyed the dead zones along with marine ecologist Rutger Rosenberg of the University of Gothenburg in Sweden. "That's enough to feed 75 percent of the average brown shrimp harvest from the Louisiana gulf. If there was no hypoxia and there was that much more food, don't you think the shrimp and crabs would be happier? They would certainly be fatter."

Only a few dead zones have ever recovered, such as the Black Sea, which rebounded quickly in the 1990s with the collapse of the Soviet Union and a massive reduction in fertilizer runoff from fields in Russia and Ukraine. Fertilizer contains large amounts of nitrogen, and it runs off of agricultural fields in water and into rivers, and eventually into oceans.

This fertilizer runoff, instead of contributing to more corn or wheat, feeds massive algae blooms in the coastal oceans. This algae, in turn, dies and sinks to the bottom where it is consumed by microbes, which consume oxygen in the process. More algae means more oxygen-burning, and thereby less oxygen in the water, resulting in a massive flight by those fish, crustaceans and other ocean-dwellers able to relocate as well as the mass death of immobile creatures, such as clams or other bottom-dwellers. And that's when the microbes that thrive in oxygen-free environments take over, forming vast bacterial mats that produce hydrogen sulfide, a toxic gas.

"The primary culprit in marine environments is nitrogen and, nowadays, the biggest contributor of nitrogen to marine systems is agriculture. It's the same scenario all over the world," Diaz says. "Farmers are not doing it on purpose. They'd prefer to have it stick on the land."

In addition to fertilizers, the other primary culprit is the consumption of fossil fuels. Burning gasoline and diesel results in smog-forming nitrogen oxides, which subsequently clear when rain washes the nitrogen out of the sky and, ultimately, into the ocean.

Technological improvements, such as electric or hydrogen cars, could solve that problem but the agricultural question is trickier. "Nitrogen is very slippery; it's very difficult to keep it on land," Diaz notes. "We need to find a technology to keep nitrogen from leaving the soil."

8 Comments

1. 1. jen_v 05:36 PM 8/15/08

   Cover cropping is a much more accessible, sustainable and effective method of reducing or eliminating the need for the application of nitrogen fertilizer. Of course, Monsanto and Dupont would Like you to purchase their expensive GM seed, they would Like you to think that they have the answer to a problem they are very much a part of...
   I am surprised that the SA is no more aware of the good solutions that sustainable agriculture (which is not just about sustainable agriculture, but also sustainable environment and society) have to offer - tried and tested - to this problem...

   Reply | Report Abuse | Link to this

2. 2. JustinDoDrop 06:09 PM 8/15/08

   Wow, pretty sad isnt it? Yet all the bottom feeder politicians will tell the Sheeple that everything is just hunky dory!
   
   JT
   www.FireMe.To/udi

   Reply | Report Abuse | Link to this

3. 3. teknopartz 10:07 PM 8/15/08

   Doesn't it make you wonder... today we have so much water run-off full of excess Nitrogen (which forms problematic algal blooms where not desired). At the same time we have industries setting themselves up ready to intentionally grow algae to harvest bio-diesel or whatever and 're-capture' carbon for fuel and stuff. Do the people with the Nitro/Algae problem talk to the people with the Nitro/Algae solution? Is there some way we can make these people talk to each other?

   Reply | Report Abuse | Link to this

4. 4. waggonem 04:15 PM 8/19/08

   I would like to see more exploration of bubbling air into the dead zones (in addition to, rather than as a substitute for, curtailing fertilizer and other chemical runoffs). Yes, the dead zones are in tidal waters, but the tides do not so mix up the waters as to revive the dead zones, so the tides are unlikely too much to disperse the aeration.

   Reply | Report Abuse | Link to this

5. 5. kaycee05 10:40 AM 5/5/10

   Good for making <a href="http://www.asiawriters.com">freelance writing opportunities</a>

   Reply | Report Abuse | Link to this

6. 6. SolaRoof 05:39 PM 5/21/10

   A scientist is quoted as saying: "Nitrogen is very slippery; it's very difficult to keep it on land," Diaz notes. "We need to find a technology to keep nitrogen from leaving the soil." If only Agribusiness and those who teach modern Petrochemical based production could understand that we don't need a new "technology" - what we need is to restore soils using organic and permaculture methods and stop using synthetic fertilizers that destroy soil structure and soil ecology. Healthy organic soils (unlike fertilizer) hold nitrogen in the organic material and it is released slowly by bacterial and enzymes
   action.
   
   The problem is that restoring soils around the world will take decades and the food that must be produced to feed billions will not come from wishful thinking or dreams of "new technology" which usually is code for GM plants or algae. But there is no quick fix and great dangers that we would further contaminate our ecosystem and food chain with toxic and destructive consequences.
   
   I propose an alternative approach to our food supply, which is to equip people to intensively and easily produce natural, organic food in the back yard or within our homes and communities with integrated SolaRoof greenhouse methods. Large scale Controlled Environment greenhouse growing of food, feed and fuel crops (including integrated algae) is now feasible with the SolaRoof breakthrough.

   Reply | Report Abuse | Link to this

7. 7. Ausearth 07:10 AM 6/23/10

   permaculture is a good idea

   Reply | Report Abuse | Link to this

8. 8. guido 12:58 PM 7/29/10

   In the long run reducing nitrogen fertalizer use might be the way to go, but today the problems lie with excess nitrogen in the water running into the oceans and bays. We need to deal with the problem where it is. Reducing nitrogen in any body of water is not an insoluble problem. The nitrogen can be handled before it gets into the bays and the oceans.
   
   Ask anybody who has ever had a home aquarium. You can set up biofiltration systems that put the nitrogen back into the air, where it comes from in the first place when fertalizers are manufactured. When I had an aquarium, my tap water always had nitrogen in it but the run off from my aquarium was always nitrogen free after I had added plenty of nitrogen in the fish food because I had set up an efficient nitrogen biofiltration system. Biofiltration systems can be set up in holding ponds or lakes or rivers. If you bubble off the nitrogen before it gets to bays or the oceans, the dead zones from nitrogen run off get reduced or eliminated without ruining farmers or crippling our food production systems.

   Reply | Report Abuse | Link to this