An over 7,000-square-mile wildlife "dead zone" located in the center of the Gulf of Mexico has grown from being a curiosity to a colossus over the past two decades, according to the National Wildlife Federation (NWF), and scientists are now concerned the recent oil spill and other emerging chemical threats could widen the zone even further.
This was 7,000 square miles of "dead zone" BEFORE the Gulf oil spill.
What will this oxygen depletion zone look like now?
in addition, my research shows that the MMS study for the effect of oxygen depletion due to deep water drilling underestimated the volume of "hydrocarbons" released into the environment due to a "catastrophic leak" by a factor of 10,000.
There are 188,000 to 527,000 metric tons of hydrocarbon gas being injected into the deep water gulf each day.
The dissolved natural gas being released will be more deadly than the oil.
The Gulf oxygen depletion zone or "Dead Zone" has been documented by environmentalists over the last 20 years.
This satellite image from NOAA is from 2008. The dead zone typically grows in the summer.
Scientists in Pennsylvania report that boosting production of crops used to make biofuels could make a difficult task to shrink a vast, oxygen-depleted “dead zone” in the Gulf of Mexico more difficult. The zone, which reached the size of Massachusetts in 2008, forms in summer and threatens marine life and jobs in the region. Their study is scheduled for the Oct. 1 issue of ACS’ semi-monthly journal Environmental Science & Technology.
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Now an immense amount of fossil-fuel gasses are being released into the ocean at the oil leak site.
How much gas is being released?
A BP executive stated that they were removing 3000:1 gas to oil at the well before the explosion. (thats 3000 barrels of gas for every barrel of oil) The amount of oil leaking into the gulf is 25,000 to 70,000 barrels.
at 3000:1 this would mean 75 - 210 million barrels of gas per day being released.
There is 5.64 cubic feet of gas per barrel.
That would mean there is 13.3 to 37.2 million cubic feet of gas being released each day.
(note: this is at standard atmospheric temp and pressure. At the ocean floor and 2,400 pounds per square inch, this gas is compressed by a factor of of over 1000 and will expand as it rises. So, in the video coming out of the pipe it looks like 75,000 to 210,000 barrels of gas per day.
you see, what happens when methane is released into the gulf? It goes into solution. There, in the deep ocean, it oxidizes, stripping the ocean of oxygen and forming carbon dioxide and water.
This report, contracted by MMS, and titled: "Deepwater Program: Understanding the Processes that Maintain the Oxygen Levels in the Deep Gulf of Mexico" was contracted to see what the effects of deepwater drilling would be on the oxygen content of the gulf.
They found that there are three regions of oxygen in the gulf, the oxygen- upper waters from 0-200 meters down, the oxygen minimum zone from 300-700 meters down, and the relatively dense, oxygen rich deep water brought by currents at a depth of 800-1500 meters.
it looks kind of like this, with the oxygen level going up again at deeper levels.
They found that the majority of dissolved oxygen in the deep water gulf (>400 meters)is due to current inflow, which then circulates within the depths of the gulf, since the exit at the Florida keys is so shallow.
"For deeper waters, the major source is transport of relatively dense, oxygen-rich water masses through the Yucatan Channel into the Gulf interior"
The study goes on to say that,
The Gulf of Mexico Basin is in no danger of becoming anoxic due either to natural processes, oil and gas production, or other anthropogenic effects. Decreased oxygen levels, however, could occur in localized areas.
In this they are talking about NORMAL oil production occurrences. they are also only looking at oxygen depletion caused by the long-term breakdown of oil.
Because discharges of oil or gas can consume oxygen during their degradation
Now, this is certainly going to occur, and for a long-long time, the oxygen rich waters flowing into the deep gulf will become depleted as the oil breaks down. That is on the long term. On the shorter term the real issue is the growing deep water dead zone of hydrocarbon-rich/oxygen-poor waters in the gulf at depths greater than 700 meters.
As this deep water dead zone moves into the loop current, it will recirculate in the gulf since the outflow of the gulf is at shallow depth. (from the study)
The Gulf of Mexico is a semi-enclosed sea with two ports. The
major inflow port is at the Yucatan Channel, which has a sill depth that is deep enough (~2,000 m) to allow the transport of relatively dense, oxygen-rich deep source waters from the Atlantic Ocean into the Gulf from the Caribbean Sea. The Loop Current brings these waters in. The major outflow port at the Florida Straits is shallow enough (~800m) that the deeper, oxygen rich waters can mix into the interior of the Gulf, rather than flowing directly out with the Loop Current.
So the Deep Water Dead Zone of the gulf will recirculate within the gulf of mexico, moving up the shore of Florida and back toward the coasts of Louisiana. It will spread through a majority of the area of the deep gulf.
This deep water oxygen depletion zone has the potential of killing most deep water sea life in the entire Gulf of Mexico.
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More on the MMS study
This study by MMS on the effect of oxygen depletion on the gulf of mexico is woefully inadequate. When they say that a "catastrophic oil spill" in the gulf would not lead to a "significant alteration of the oxygen supply", they underestimated the amount of hydrocarbons leaked into the gulf by a factor of 10,000. (see below)
In the event of analysis of the potential effect on the gulf oxygen contents they only look at the effects of oxygen depletion caused by oil decomposition.
They estimate that:
Catastrophic oil spills can introduce hydrocarbons at 2-3 times the rate of natural seeps, but such an input will not significantly alter the oxygen supply. There may be local effects from anthropogenic discharges, but the oxygen database is not adequate to assess them.
so, they say that the most catastrophic discharge will only be 2-3 times the natural seeps. Let's check that with reality. . .why don't we. . .
They say the natural seeps produce 140,000 +/- 60,000 Metric Tonnes of hydrocarbons per year. They say a "catastrophic" leak will produce 2-3 times that amount per year.
1 barrel of oil per day = 50 Tonnes of oil per year (approx)
current oil outflow is between 25,000 and 70,000 barrels per day
This equals 1.25 to 3.5 MILLION tonnes of oil per year.
at this rate, in the last 21 days between 71,918 and 201,370 metric tonnes of oil have ALREADY been released.
AND THAT IS JUST THE OIL
But what about the gases? the study says that the release above was hydrocarbons, not just oil.
from above:
That would mean there is 13.3 to 37.2 million cubic feet of gas being released each day
.
there are 70.6 million cubic feet of natural gas in one million metric tons of gas.
that means 188,000 to 527,000 metric tons of gas are being released each day.
how does that compare with 140,000 +/- 60,000 metric tons of hydrocarbons per year???
68,620,000 to 192,000,000 metric tons of gas per year
+
1,250,000 to 3,500,000 metric tons of oil per year
IT DOESN'T
woefully inadequate = the definition of MMS
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additional comment on the study:
when they say:
Complete oxidation of the U.S. Gulf oil and gas reserves, which are on the order of 10 billion barrels, would consume <1% of the standing oxygen supply. </p>
They are talking about long-term oxygen depletion due to oxidation of hydrocarbons, not the effects of the immediate release. They are also including the oxygen located in the super oxygen-rich shallow waters found between 0-70 meters down. The decomposition of the oil will occur below the "oxygen minimum" barrier between the depths of 300-700 meters down. This will provide a buffer zone where depletion in the deep water will be isolated from the oxygen rich surface and will draw exclusively from the deep-water oxygen reserves.
note that they add the caveat:
There may be local effects from anthropogenic discharges, but the oxygen database is not adequate to assess them.
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Here is some supporting information:
The Gulf Oils Spill: "A Dead Zone in the Making"?
Mississippi Scientists Find Oxygen Depletion Near Oil Leak
Oil Spill Science: The Smoking Gun
Understand the Processes that Maintain Oxygen Levels in the Deep Gulf of Mexico - an MMS study
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Thanks for the rescue!
I really think that this is the most significant issue. The amount of natural gas being released is 3000 times more in mass than the oil. But people only talk about the oil!
Oxygen depletion in the deep water zones is significant because there is a buffer of low-oxygen between depths of 300 and 700 meters. All oxygen depletion that occurs due to the breakdown of hydrocarbons below this level will be isolated from the surface, leading to an even larger "dead zone" in the deep.
The MMS study is intentionally inadequate. It is not peer reviewed and does not address the stratification of oxygen levels in the deep gulf waters. This study was supposed to be looking at possible impacts of deep water drilling but underestimates the "worst case" scenario from what is currently happening in the gulf by a factor of 10,000.
The fact that the natural gas is coming out at a rate of 3000:1 has not been mentioned in the media. CNN is still reporting that 210,000 gallons (5,000 barrels per day) is the "general consensus" levels of oil. A total misrepresentation.
It is up to the government to force BP to do a proper estimation of gas and oil leak rates using accurate measurements.