Global warming led to atmospheric hydrogen sulfide and Permian extinction

Penn State ^ | February 22, 2005

[snarks_when_bored]

Global warming led to atmospheric hydrogen sulfide and permian extinction
Tuesday, February 22, 2005
Washington, D.C. -– Volcanic eruptions in Siberia 251 million years ago may have started a cascade of events leading to high hydrogen sulfide levels in the oceans and atmosphere and precipitating the largest mass extinction in Earth’s history, according to a Penn State geoscientist. "The recent dating of the Siberian trap volcanoes to be contemporaneous with the end-Permian extinction suggests that they were the trigger for the environmental events that caused the extinctions," says Lee R. Kump, professor of geosciences. "But the warming caused by these volcanoes through carbon dioxide emissions would not be large enough to cause mass extinctions by itself." That warming, however, could set off a series of events that led to mass extinction. During the end-Permian extinction 95 percent of all species on Earth became extinct, compared to only 75 percent during the K-T when a large asteroid apparently caused the dinosaurs to disappear. Volcanic carbon dioxide would cause atmospheric warming that would, in turn, warm surface ocean water. Normally, the deep ocean gets its oxygen from the atmosphere at the poles. Cold water there soaks up oxygen from the air and because cold water is dense, it sinks and slowly moves equator-ward, taking oxygen with it. The warmer the water, the less oxygen can dissolve and the slower the water sinks and moves toward the equator. “Warmer water slows the conveyer belt and brings less oxygen to the deep oceans,” says Kump. The constant rain of organic debris produced by marine plants and animals, needs oxygen to decompose. With less oxygen, fewer organics are aerobically consumed. "Today, there are not enough organics in the oceans to go anoxic," says Kump. "But in the Permian, if the warming from the volcanic carbon dioxide decreased oceanic oxygen, especially if atmospheric oxygen levels were lower, the oceans would be depleted of oxygen." Once the oxygen is gone, the oceans become the realm of bacteria that obtain their oxygen from sulfur oxide compounds. These bacteria strip oxygen from the compounds and produce hydrogen sulfide. Hydrogen sulfide kills aerobic organisms. Humans can smell hydrogen sulfide gas, the smell of rotten cabbage, in the parts per trillion range. In the deeps of the Black Sea today, hydrogen sulfide exists at about 200 parts per million. This is a toxic brew in which any aerobic, oxygen-needing organism would die. For the Black Sea, the hydrogen sulfide stays in the depths because our rich oxygen atmosphere mixes in the top layer of water and controls the diffusion of hydrogen sulfide upwards. In the end-Permian, as the levels of atmospheric oxygen fell and the levels of hydrogen sulfide and carbon dioxide rose, the upper levels of the oceans could have become rich in hydrogen sulfide catastrophically. This would kill most the oceanic plants and animals. The hydrogen sulfide dispersing in the atmosphere would kill most terrestrial life. "A hydrogen sulfide atmosphere fits the extinction better than one enriched in carbon dioxide," says Kump. "Carbon dioxide would have a profound effect on marine life, but terrestrial plants thrive on carbon dioxide, yet they are included in the extinction." Another piece in the puzzle surrounding this extinction is that hydrogen sulfide gas destroys the ozone layer. Recently, Dr. Henk Visscher of Utrecht University and his colleagues suggested that there are fossil spores from the end-Permian that show deformities that researchers suspect were caused by ultra violet light. "These deformities fit the idea that the ozone layer was damaged, letting in more ultra violet," says Kump. Once this process is underway, methane produced in the ample swamps of this time period has little in the atmosphere to destroy it. The atmosphere becomes one of hydrogen sulfide, methane and ultra violet radiation. The Penn State researcher and his colleagues are looking for biomarkers, indications of photosynthetic sulfur bacteria in deep-sea sediments to complement such biomarkers recently reported in shallow water sediments of this age by Kliti Grice, Curtin University of Technology, Australia, and colleagues in the Feb. 4 issue of the journal, Science. These bacteria live in places where no oxygen exists, but there is some sunlight. They would have been in their heyday in the end-Permian. Finding evidence of green sulfur bacteria would provide evidence for hydrogen sulfide as the cause of the mass extinctions.

[snarks_when_bored]

95% of all living species disappeared in the Permian extinction. Hydrogen sulfide might have been the cause.

[beyond the sea]

Volcanic eruptions in Siberia 251 million years ago may have started a cascade of events

251,000,000 -- how accurate!

;-)

[beyond the sea]

95% of all living species disappeared in the Permian extinction.

But the likes of Janet Reno survived. Where's the justice in nature?

;-)

[snarks_when_bored]

Could be the press release writer's fault.

[snarks_when_bored]

(rimshot)

[Dog Gone]

We had to get rid of those nasty trilobites somehow.

[yer gonna put yer eye out]

Did you know that Algore discovered hydrogen sulfide? :0)

[YOUGOTIT]

There is no way that a statement like that can be believed. It is a theory, as with the people who believe that the earth turned into a snowball and ended most life or was that another time.

[Buwan]

They had SUVs way back then?

[Uncle Miltie]

Hydrogen Sulfide: If Siberian gaseous emissions were enough to kill most species, it really ought to lay off the chili.

[snarks_when_bored]

There is no way that a statement like that can be believed. It is a theory, as with the people who believe that the earth turned into a snowball and ended most life or was that another time.

As the article says: "Finding evidence of green sulfur bacteria would provide evidence for hydrogen sulfide as the cause of the mass extinctions."

It's research in progress, not intended to be believed, but rather examined and weighed.

[Noachian]

Let's see if I have this right:

If every country signed the Kyoto Treaty, and we all went back to living in the preindustrial age, nature could still come along and wipe us all out. Is that right?

[snarks_when_bored]

Yep.

[ClearCase_guy]

This idea that volcanoes near the arctic circle could cause Global Warming ... fascinating ... I wonder ... could it happen again? If we were to find ... let's say ... a chain of volcanoes near Alaska ... that were, you know ... warming the arctic waters ... could that cause Global Warming? Or is this something that only worked 251 million years ago?

[muawiyah]

There have been many such destructions. They are all believable.

[corkoman]

There is no way that a statement like that can be believed. It is a theory, as with the people who believe that the earth turned into a snowball and ended most life or was that another time.

You are being generous. It is not a theory, as theories are based on a lot of testing and observation.

This is a hypothesis, nothing more.

[snarks_when_bored]

I'm not sure that a link has been posted on FR to the Kyoto Count Up, a page at JunkScience.com. It's pretty interesting:

Kyoto Count Up

[snarks_when_bored]

Those Siberian Trap volcanoes threw truly staggering amounts of ash and chemicals into the atmosphere. If such eruptions happened today, bad stuff could happen again.

[muawiyah]

The volcanic eruptions in Siberia were many times larger than those going on these days. There were also large eruptions in India at a different period of time.

There's a theory that large globules of very hot rock "float" to the surface from time to time, and then break through! Some geologists believe the so-called "super volcanos" sit on top of such globules. Yellowstone is such a place, and if it bubbled through it'd kill us all!

Then there are the rocks that fall from the sky. Some are very small. Some are very large. It happens!

[muawiyah]

The "snowball" hypothesis left a layer of large gravel in this area. I spent months pulling those rocks out of my lawn when I first bought this house.