There's a paper out about computer simulation of the atmosphere at the time of the Permian-Triassic Boundary and during the PT Extinction. The model aimed at determining whether or not the hydrogen sulfide had a great an impact upon the atmospheric chemistry. As currently theorized H2S has a huge impact upon the event and may have been one of the main kill mechanisms.
There were probably two ways that H2S was such a powerful kill mechanism. The first was directly: H2S is a nasty chemical. As the waters of the Permian Ocean warmed and became more and more anoxic, bacteria that produce the stuff became more and more common until very large parts of the ocean were belching the stuff. More and more depths of the sea became poisoned. The warmth of the ocean combined with the anoxia and hydrogen sulfide is probably the main killing mechanism in the sea.
There is a suspicion that in the terrestrial environs, hydrogen sulfide killed in three ways. The first is the classic acid rain scenario. The second is direct inhalation or exposure near the ocean. Finally, and possibly the most important many variants of the model is the mixing with the upper atmosphere. Up there, it would react with the ever important ozone that protects life from all that harmful UV radiation. When it did, the UV blasted the terrestrial ecosystems in a pretty nasty way. It also, by reacting with the ozone, made it possible to extend the period of time that the methane hydrate belching would continue to oven cook the planet in conjunction with the carbon dioxide coughed up in massive amounts by the Siberian Traps. I blogged some time ago about the Permian Triassic Extinction. That was the current understanding of the PT Extinction mechanism. Then along came this paper. So how much does this paper change that understanding? What does the paper say?
The paper proposes that based on their own 2 D modeling that there was no way for the hydrogen sulfide to be transported to the upper atmosphere where the ozone layer is reside. One of the primary problems with this is, according to the paper, the tropics are an oxiding zone that would remove the hydrogen sulfide from circulation prior to updrafting. Obviously they had a chem model attached and are confident in their findings. Their paper appeared in Nature Geoscience.
Color me skeptical, but I am going to have to wait until I have a moment to read the whole paper to see what they have to say. That moment isn't now. This week is crunch week for the mischief project. I'm getting sponsors, but will it be enough? We shall see!
That said, a hat tip goes to Paleoblog for calling this to my attention.
There were probably two ways that H2S was such a powerful kill mechanism. The first was directly: H2S is a nasty chemical. As the waters of the Permian Ocean warmed and became more and more anoxic, bacteria that produce the stuff became more and more common until very large parts of the ocean were belching the stuff. More and more depths of the sea became poisoned. The warmth of the ocean combined with the anoxia and hydrogen sulfide is probably the main killing mechanism in the sea.
There is a suspicion that in the terrestrial environs, hydrogen sulfide killed in three ways. The first is the classic acid rain scenario. The second is direct inhalation or exposure near the ocean. Finally, and possibly the most important many variants of the model is the mixing with the upper atmosphere. Up there, it would react with the ever important ozone that protects life from all that harmful UV radiation. When it did, the UV blasted the terrestrial ecosystems in a pretty nasty way. It also, by reacting with the ozone, made it possible to extend the period of time that the methane hydrate belching would continue to oven cook the planet in conjunction with the carbon dioxide coughed up in massive amounts by the Siberian Traps. I blogged some time ago about the Permian Triassic Extinction. That was the current understanding of the PT Extinction mechanism. Then along came this paper. So how much does this paper change that understanding? What does the paper say?
The paper proposes that based on their own 2 D modeling that there was no way for the hydrogen sulfide to be transported to the upper atmosphere where the ozone layer is reside. One of the primary problems with this is, according to the paper, the tropics are an oxiding zone that would remove the hydrogen sulfide from circulation prior to updrafting. Obviously they had a chem model attached and are confident in their findings. Their paper appeared in Nature Geoscience.
Color me skeptical, but I am going to have to wait until I have a moment to read the whole paper to see what they have to say. That moment isn't now. This week is crunch week for the mischief project. I'm getting sponsors, but will it be enough? We shall see!
That said, a hat tip goes to Paleoblog for calling this to my attention.
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