Dead zone may 2010. It is now bigger.

The “Dead Zone”, the low-oxygen area in the Gulf of Mexico, which has been recorded this year, might just be the largest on record and it overlaps areas which were affected by the oil spill courtesy of our Eco-friendly oil conglomerate BP.

The areas afflicted with low levels of oxygen, also known as hypoxia, cover an area estimated to be over 7,000 square miles of the bottom of the Gulf of Mexico and extended as far as to actually enter Texas waters. This astonishing discovery was made by researchers at the Louisiana Universities Marine Consortium, after performing a survey of the waters.

The area covered is expected to have included a section off of Galveston, Texas, as well, however poor weather conditions forced the researchers to cut their surveying trip short.

“The total area probably would have been the largest if we had enough time to completely map the western part,” said the consortium’s executive director, Nancy Rabalais.

The largest dead zone that was ever measured in a survey, which started on a regular basis in 1985, was slightly more than 8,000 square miles, and was recorded in 2001.

This annual summer “dead zone” in the Gulf of Mexico is generally attributed to chemicals used by farmers, and which make their way to the Gulf by means of the Mississippi and Atchafalaya rivers.
The phosphorous and nitrogen contained in agricultural runoffs provide a food source which allows algae to prosper in the Gulf.

When bits of algae die off, or are excreted by sea animals which eat them settle onto the bottom of the water, they decompose and the bacteria consume the oxygen in the water.

The end result, the scientists explained, is that this causes oxygen depletion in the water, which forces many marine animals including fish, shrimp and crabs to either vacate their homes, or suffocate.

The marine life which makes its home in the sediments can survive with relatively little oxygen, however they will begin to die off as the oxygen level approaches zero.

To be considered as part of this “Dead Zone”, the oxygen levels in bottom waters in the Gulf of Mexico need to be at a level of 2 parts per million or less.

By the end of July this year, large areas of the norther part of the Gulf of Mexico had already reached that level, including one part close to Galveston Bay.

The area which the BP oil spill overlaps in some areas in the “Dead Zone”, Rabalais explained, and microbes which would be used to help clean up the spill can deplete oxygen levels in the water.

Be that as it may, scientists could not say that there is a definite link between the devastating oil spill, and the size of the “Dead Zone”.

“It would be difficult to link conditions seen this summer with oil from the BP spill in either a positive or negative way,” Rabalais explained.

Namibia

Researchers have found a “super fish” which is actually able to not only survive, but thrive in a previously thought uninhabitable region off of Africa’s south-west coast, which also happens to be infested by jellyfish.

This “super fish” is actually helping to keep the local ecosystem going, and is single handedly helping to preserve an important fishery as well.

One of the ecosystems off the coast of Namibia, the Beguela ecosystem, was at one point is history chock full of sardines. However, overfishing of the area, and various other environmental factors have caused the population of sardines to take a nose dive, and the ecosystem became overrun with algal blooms and jellyfish swarms.

The algae has almost consumed the entire oxygen supply of the water, and the waters closer to the surface are full of jellyfish and algae.

It has been discovered that bearded gobies are making their home at the very bottom, and they are the only vertebrate to do so. The stomach contents were examined, and revealed that these bearded fish eat the dead algae which falls from the surface, and they also eat the jellyfish! This astounding discovery was made by Anne Utne-Palm, of the University of Bergen, Norway and several of her collegues.

The team of researchers also discovered that the gobies are able to survive for hours in water with extremely low oxygen levels by lowering their metabolic rate, and when they run low they pop back to the surface for more oxygen!

What a Fish!

According to predictions made by a team of NOAA-supported scientists from the Louisiana Universities Marine Consortium, Louisiana State University, and the University of Michigan, the Gulf of Mexico “dead zone” is likely to become record big this summer. If there predictions are true, we will see a dead zone the size of New Jersey (7,450 to 8,456 square miles). Additional flooding of the Mississippi River since May can however increase these numbers even further.

What is the Gulf of Mexico ‘dead zone’?

The dead zone is an area off the coast of Louisiana and Texas in the Gulf of Mexico where the oxygen level seasonally drops so low that most life forms living in and close to the bottom dies.

Dead zones are the result of large amounts of nutrients reaching the water, e.g. through waterways polluted by sewage and agricultural runoff. The excess nutrients stimulate rapid and massive algae growth in the affected area, a so called algae bloom. When the algae die, they sink to the bottom where oxygen dependant bacteria begin to break them down. The decomposition process consumes vast amounts of oxygen and soon the bottom and near-bottom waters become so oxygen depleted that all sorts of oxygen breathing organisms begin to die. This so called hypoxic area (an area where the oxygen levels are low to non-existent) is not just a problem for wildlife; it can also damage the economy of nearby states since it destroys habitat necessary for commercial and recreational Gulf fisheries.

The largest dead zone on record appeared in 2002 and measured 8,484 square miles.

Mississippi and Atchafalaya Rivers too rich in nutrients

During April and May this year, the Mississippi and Atchafalaya Rivers experienced heavy water flows that were 11 percent above average.

“The high water volume flows coupled with nearly triple the nitrogen concentrations in these rivers over the past 50 years from human activities has led to a dramatic increase in the size of the dead zone,” said Gene Turner, Ph.D., a lead forecast modeler from Louisiana State University.

“As with weather forecasts, this forecast uses multiple models to predict the range of the expected size of the dead zone“, said Robert Magnien, Ph.D., director of NOAA’s Center for Sponsored Coastal Ocean Research. “The strong track record of these models reinforces our confidence in the link between excess nutrients from the Mississippi River and the dead zone.”