Listen to this PodcastMore 60-Second Earth
-
The Best Science Writing Online 2012
Showcasing more than fifty of the most provocative, original, and significant online essays from 2011, The Best Science Writing Online 2012 will change the way...
Read More »
There's a dead zone forming in the Gulf of Mexico, and I'm not talking about the ongoing oil gushing from BP's well.
No, it's the annual dead zone that forms thanks to all the fertilizers washing off Midwestern farm fields. These chemicals flow from tributaries into the Mighty Mississippi and then are carried by Old Muddy down to the Gulf.
Once there the nitrogen promotes algae growth. When the algae dies, it sinks and microbes feast on its corpse, sucking oxygen out of the surrounding waters in the process.
The result is deep water that's devoid of oxygen. This is bad news for creatures on the sea floor such as coral or slow-moving crabs and worms.
Scientists at the Louisiana Universities Marine Consortium predict that this year's dead zone will cover an area roughly the size of New Jersey, just shy of the record set back in 2002.
Nearly 120,000 metric tons of nitrogen made it to the Gulf in May of this year. That makes for a big algae bloom and a big dead zone.
What's worse, the oil spill could make it even bigger. Turns out that the microbes cleaning up that mess use oxygen, too.
—David Biello, with narration by Christie Nicholson
See what we're tweeting about
8 Comments
Add CommentThis report seems to indicate that this is an isolated annual occurrence rather than a widespread persistent condition. Do many of the animals living in the deadening zone leave to greener pastures? Just how serious is this problem, really?
Reply | Report Abuse | Link to thisIf it is a serious problem, doesn't also affect the entire Mississippi River watershed? In that case shouldn't the use of nitrogen in fertilizers be regulated?
Just a supposition, jtdwyer, to your second pair of questions....
Reply | Report Abuse | Link to thisPerhaps the concentration of nitrogen is significantly higher in the area around the Mississippi Delta than throughout the river itself. And I'd imagine that farming interests have successfully lobbied against regulation of fertilizers and their use.
akmangalick - Thanks - you could be right about nitrogen just showing up in the Delta, but I think it is just the final destination of fertilizer runoff from the fields of corporate farms across the middle of the country.
Reply | Report Abuse | Link to thisOf course those corporations have and would lobby against the regulation of fertilizer use, as would the rest of the country if they knew what it would do to crop yields and food prices. Not that alternative farming methods couldn't be implemented...
Plants need nitrogen. It is possible to cut back on nitrogen runoff but that of course requires regulation and creates expense, etc. Eutrophication DOES affect the river itself, but in different ways. The mixing of water in a river for example doesn't really allow for the build up of a dead zone, instead you get excess plant growth clogging the waterway. In the long run though its a big river and it keeps flowing. Phosphorus pollution is also a problem but for other reasons.
Reply | Report Abuse | Link to thisI think the basic truth is that with such a huge population of people around the globe this kind of degradation is almost unavoidable. Money interests are not usually very helpful though.
I agree with your basic truth. The thing I can't understand is why nature has 'permitted' an over population of a single species at the expense of all others. Why? What is it hedging against by not limiting our ability to overpopulate. Is there a mass die off in our near future?
Reply | Report Abuse | Link to thisNature neither permits nor denies nor plans. Nature simply is that which is. Large fluctuations in populations of species are pretty common. Humanity is no different. There have apparently also been huge explosions of the population of some species in the past. Around the P-T boundary for instance Listrosaurus appears to have multiplied to gigantic numbers. Soon it was extinct.
Reply | Report Abuse | Link to thisrshoff - Humanity has been very clever about managing the environment to the short term benefit of specific groups and humanity in general. Disregarding long term effects can produce disadvantageous results, such as extreme population densities and resource requirement shortfalls, especially food, water, arable land, etc.
Reply | Report Abuse | Link to thisSince 1950 the world population has increased from about 2.5 billion to nearly 7 billion today. This has been achieved primarily by increased food production and efficiently mechanized harvesting methods.
Unfortunately, improper irrigation methods, occupation of productive crop land and other factors are significantly reducing the availability of arable land. Highly efficient over harvesting of seafish is diminishing a critical source of nutrition. Diversion and consumption of ancient nonrenewed fresh water reservoirs are limiting availability. These and other issues (global warming, rising sealevels, etc.) mitigate against even the continued survival of current population levels, much less the continuation of traditional population growth. A catastrophic collapse of support infrastructure is certainly a critical concern, even if some humane method of population reduction is identified.
The Mississippi Delta dead zone will not likely be the primary contributor to the extinction of humanity, but there is an increasing list of potential candidates.
Here in Missouri, men have the lowest sperm count in the country because of the fertilizers in the Missouri and Kaw rivers, which is used for drinking water. The chemicals used to kill bugs also contributes to low sperm count and birth defects.
Reply | Report Abuse | Link to this