THE Hydrogen Thread (merged) Part 2

Graeme

Israeli invention could pave way for hydrogen cars

Kylon · Expert Joined: Aug 12, 2005 Posts: 803

Hydrogen Sulfide, Not Carbon Dioxide, May Have Caused Largest Mass Extinction
""However, we find mass extinction on land to be an unlikely consequence of carbon dioxide levels of only seven times the preindustrial level," Kump told attendees today (Nov. 3) at the annual meeting of the Geological Society of America in Seattle. "Plants, in general, love carbon dioxide, so it is difficult to think of carbon dioxide as a good kill mechanism."
On the other hand, hydrogen sulfide gas, produced in the oceans through sulfate decomposition by sulfur bacteria, can easily kill both terrestrial and oceanic plants and animals.

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 34 part 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 of the oceanic plants and animals. The hydrogen sulfide dispersing in the atmosphere would kill most terrestrial life. "

""We are looking for biomarkers, indications of photosynthetic sulfur bacteria," says Kump. "These photo autotrophic organisms live in places where there is no oxygen, but still some sunlight. They would have been in their hay day in the end-Permian." Finding biomarkers of green sulfur bacteria would provide evidence for hydrogen sulfide as the cause of the mass extinctions. " link

This is referring to the Permian Triassic Extinction event.

steam_cannon · Expert Joined: Dec 28, 2006 Posts: 2421 Location: MA

Yup. But don't worry, that probably won't happen again.

dohboi · Light Sweet Crude Joined: Dec 05, 2005 Posts: 1114

Hmmm. It seems that you need to change your title.
As your own quote states, it was both carbon dioxide and hydrogen sulfide that caused the extinctions. Or rather H2S was most of the immediate cause while CO2 and methane helped establish conditions that lead to the formation of H2S.
Peter Ward's "Under a Green Sky" is the work to read to understand this rather complex story.

I like the point in sc's quote--we've already killed off so much oceanic life that there's not enough left to produce the massive hydrogen sulfide eruptions that caused earlier extinctions!
On the other hand...
I have to track it down, but I saw something on public TV the other night about mysterious H2S eruptions off the coast of SW Africa. Perhaps it's already happening?

steam_cannon · Expert Joined: Dec 28, 2006 Posts: 2421 Location: MA

Kylon · Expert Joined: Aug 12, 2005 Posts: 803

There's more! link

"Millions of years before the dinosaurs were apparently killed by an asteroid hitting our planet, the Earth experienced another mass extinction that was far more devastating. The cause for that, paleontologist Peter Ward says, was actually homegrown: Hydrogen sulfide in the oceans and atmosphere turned the sky green and choked off oxygen for plants, animals and marine life.

Ward, who teaches at the University of Washington and who spoke at the Technology, Entertainment and Design (TED) conference last week, says that global warming caused by humans could reproduce the same hydrogen sulfide gas conditions that killed more than 90 percent of life during the Permian period, when the extinction occurred. And we might just do it faster than nature did.

Ward, who published a book about the extinctions last year called Under a Green Sky, is involved in a project with Arizona State University to design a $60 million atmosphere chamber to reproduce the Earth's atmospheric conditions from the Permian period--as well as any other period they want -- and recreate the die-off with plants grown in the chambers. The aim is to see what kinds of signs are left behind so they can then look for them in nature today and see what they tell us about evolution.

Although hydrogen sulfide has the potential to be a mass murderer, researchers have recently discovered a possible medical use for the deadly gas that could, ironically, also save millions of lives. Tests have only been conducted on mice, but so far they show that hydrogen sulfide injected directly into the heart of mice suffering a medically induced heart attack puts their bodies into a state of suspended animation and results in the heart cells sustaining less damage than those of mice who did not receive the injections.

Ward spoke with Wired.com about the possible risks and benefits of hydrogen sulfide and how gas masks may be in our future. "
Wired: Explain how the Permian mass extinction occurred.
Peter Ward: Step one is, there's an enormous release of flood basalts coming out of cracks in the earth, and huge amounts of magma from the deep Earth comes out. These things go on for millions of years, and the volume of lava is extraordinary. It may have covered an area the size of the continental U.S.

Now, the lava doesn't kill much, except the poor, stupid animals that were crazy enough to be around there. But as the lava comes out, carbon dioxide bubbles out with it and a lot of carbon dioxide goes into the atmosphere to the point that we estimate the carbon dioxide levels hit 3,000 parts per million. [Current carbon dioxide levels are about 380 parts per million.]

This causes the oceans and the planet to warm, and once you do that you stop ocean currents. Once you stop currents, you lose oxygen in the ocean, because it's circulation that keeps the ocean oxygenated. This allows a type of bacteria to take over that creates hydrogen sulfide (H2S). Animal life cannot live in water that has a lot of hydrogen sulfide in it. When you have concentrations of greater than 80 ppm of hydrogen sulfide, or you get up to 200 ppm, which is easily done, you'll kill every animal [in the ocean]. Eventually so much hydrogen sulfide leaks into the atmosphere that it kills animals and plants.

Wired: How many land species were there at the time and how many were killed?
Ward: On land you had hundreds of species of mammal-like reptiles -- the first stage of mammals. It was over 90 percent extinction, not just of land animals but of ocean animals and plants. Only 50 percent [of species] in the asteroid-dinosaur stage died. So this was way, way worse.

Wired: How long did it take for this to happen?
Ward: It occurred slowly, over thousands of years. We still do not know precisely how long.

Wired: It's believed that hydrogen sulfide was the cause of at least two other mass extinctions, right?
Ward: Actually, I think it's up to 12. Every mass extinction except the dinosaur extinction seems to have been caused by this. It's all about when the Earth decides to spit out these big burps of magma that come to the surface. But a big mass extinction from global warming has not happened in 100 million years.

Wired: We place the blame for our current global warming situation on rising CO2 levels created by man. But the previous episodes of global warming and mass extinctions were entirely the cause of nature. It seems as if we could do everything in our power to reduce man-made global warming and still face global warming and mass extinction from nature if we have flood basalts at the level that occurred during the Permian period.
Ward: Not really -- those past episodes were from very rare flood basalts. There may not be another of these, as the Earth is cooling as it ages.

But we've had these mass extinctions [from hydrogen sulfide] when carbon dioxide has hit 1,000 ppm. We have not hit that [level] for 100 million years. But we are currently at 380 ppm -- and climbing rapidly at 2 ppm a year and accelerating -- and this is the highest CO2 I think in the last 40 million years. The only time [these extinctions] ever happened in the past is when these big flood basalts happened. But now we're making it happen far faster than the flood basalts ever did. This is a unique event in the history of the planet.

Wired: What would life look like as the Earth's oxygen is slowly choked off by hydrogen sulfide and how long would it take?
Ward: This really is a long way off. This is something that's going to take thousands of years. The oceans take a long time to change from oxygenated to a place where there is no oxygen on the bottom. But once it starts, you can't stop it.

I think sea-level rise is a more imminent danger. The thing that we have to do is, we have to save the ice caps, because if the ice caps go, (the hydrogen sulfide scenario) is the inevitable next step. One thousand ppm (of CO2) is all it would take to get rid of all the ice caps on the planet. We'll be at 1,000 in 200 years or less. Which means good-bye ice caps on planet Earth, which means 240 feet of sea level, which means good-bye San Francisco, Seattle, New York and on and on.

But if losing the ice caps makes us uncomfortable [because of rising water], the hydrogen sulfide is going to make us extinct. In 500 years, I can see a world where everyone will be wearing gas masks. Those that [have] them will live; those that don't will die. We humans are here for the long haul, and if we do not stop heating our atmosphere, we will suffer a very nasty fate.

There's 1 more page at the website. At least I know I can survive via gas mask!

Graeme

swissinfo
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steam_cannon · Expert Joined: Dec 28, 2006 Posts: 2421 Location: MA

Excellent post! It's definitely going to be interesting...

dohboi · Light Sweet Crude Joined: Dec 05, 2005 Posts: 1114

Thanks for the great links, sc and kylon--you guys are awesome!

rockdoc123 · Light Sweet Crude Joined: May 16, 2005 Posts: 1658

There are a number of theories for the Permian extinction...this is just one of about five or six I have read. Everything from volcanic activity to asteroid impact.
Don't confuse theories with fact.

EnergyUnlimited · Fission Joined: May 15, 2006 Posts: 2918

fraggie · Coal Joined: Dec 27, 2006 Posts: 3

Would it be feasable to use solar power to make hydrogen ?
Not talking industry scale here mind you.
just enough to run your car ?

funzone36 · Heavy Crude Joined: Dec 04, 2005 Posts: 179

technically feasible if you have a water source. not sure if you'd have to sacrifice energy usage for your other personal needs. You'll also need to know how to store your hydrogen.

kpeavey · Expert Joined: Oct 04, 2004 Posts: 1039

Absolutely. Solar photovoltaics produce DC electricity which can be used directly or stored in batteries:
-stick the ends of the circuit in a bucket of water in a manner that prevents contact
-put a glass jar over each end
-one end will produce 2x the amount of gas as the other, this would be hydrogen. The lesser volume is the oxygen, also useful.
-the gasses can be drawn off for storage in whatever container you see fit
-as long as there is a current and water, the gasses will be produced

solar PV is a fine method, as it has no moving parts or fuel requirements. Production volume is a factor of wattage.
A particular problem with hydrogen is storage. Being the smallest atom, just about any storage container is bound to leak. Ventilation of the storage area is prudent, and it would be wise not to smoke in the area.
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