Tuesday, July 25, 2006


No shrimp, Sherlock

NOAA, via Truthout: A team of scientists from the NOAA National Centers for Coastal Ocean Science, Louisiana Universities Marine Consortium and Louisiana State University is forecasting that the "Dead Zone" off the coast of Louisiana and Texas this summer will be larger than the average size since 1990. ... The "Dead Zone" is an area in the Gulf of Mexico where seasonal oxygen levels drop too low to support most life in bottom and near-bottom waters. It is caused by a seasonal change where algal growth, stimulated by input of nutrients such as nitrogen and phosphorus from the Mississippi and Atchafalaya rivers, settles and decays in the bottom waters. The decaying algae consume oxygen faster than it can be replenished from the surface, leading to decreased levels of dissolved oxygen. ... Research indicates that nearly tripling the nitrogen load into the Gulf over the past 50 years has led to the heightened Gulf of Mexico hypoxia problem. The scientists say their research will improve assessments of hypoxic effects under various Gulf Coast oceanographic conditions. And where would those nitrates be coming from? Factory hog farms, fertilizer poured on crops in non-sustainable farming, untreated human waste. Things that any sane modern nation would deal with through the logical operations of government. And who would be responsible for making sure that our government fails to do sensible regulation? The people who say that government is the problem and prove it by their personal example.
I'd also be interested to see if there isn't a study of dead zone growth related to previous seasonal hurricane activity...
Actually, Fistandantalus, hurricanes apparently tend to reduce the size of dead zones, possibly by breaking up the concentration of dead algae and other hypoxia-causing items. Here's an excerpt on a report from 2005 on the Gulf dead zone:

The size just mapped was smaller than predicted using a model developed by Dr. Eugene Turner of Louisiana State University, an investigator of the research team, that relates the size with the May nitrate load along with a term that adds the influence of the previous year's nitrate load. Turner predicted a size of 6,200 square miles, which was larger than the measured size of 4,800 square miles. The smaller than predicted size was expected because of a tropical storm and hurricane that affected the area between the Mississippi and the Atchafalaya rivers earlier in July. While the two-layered system that supports the formation of hypoxia was redeveloping at the time of the mapping cruise, the oxygen level beneath that layer had not fallen below 2 ppm again. "I would predict that a somewhat larger area of hypoxia would have been mapped if the cruise had been conducted one week later than planned and therefore closer to the size modeled by Turner," said Rabalais. Confirmation of this prediction may come from the oxygen measurements taken by the NMFS groundfish survey that finished their work on the southeast Louisiana coast on July 27 - August 31.

Ah, yes. The Mississippi watershed. The nation's sewer -- or at least it's been treated as such, especially in the "right to pollute" states. One of the reasons that huge chunks of Louisiana are wastelands now. (The other big reason, of course, is the location of so many petrochemical and other plants in the state, in a section of the state now known as "Cancer Alley".)
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