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![]() "Ron Baalke" wrote in message ... http://www.washington.edu/newsroom/n...ve/k103103.htm Ward believes low oxygen and greenhouse conditions caused by high levels of methane from intense volcanic activity are likely culprits in mass extinctions that occurred about 250 million years ago....... In ultra-low oxygen environment, such as a deep ocean, carbon exits the planetary interior in the form of methane as illustrated by deep-sea volcanos: http://www.pmel.noaa.gov/vents/chemi...ges/vents2.gif On the other hand, if a volcano erupts into the atmosphere( 21% O2), methane is explosively converted into CO2, H2S is burned into SO2, hydrogen is oxidized into steam, thereby consuming the oxygen in the atmosphere. During intense vulcanism, oxygen level may be reduced to such an extent that methane begins to escape oxidation and accumulates in the atmosphere as on Titan. John Curtis |
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![]() "Ron Baalke" wrote in message ... http://www.washington.edu/newsroom/n...ve/k103103.htm Ward believes low oxygen and greenhouse conditions caused by high levels of methane from intense volcanic activity are likely culprits in mass extinctions that occurred about 250 million years ago....... In ultra-low oxygen environment, such as a deep ocean, carbon exits the planetary interior in the form of methane as illustrated by deep-sea volcanos: http://www.pmel.noaa.gov/vents/chemi...ges/vents2.gif On the other hand, if a volcano erupts into the atmosphere( 21% O2), methane is explosively converted into CO2, H2S is burned into SO2, hydrogen is oxidized into steam, thereby consuming the oxygen in the atmosphere. During intense vulcanism, oxygen level may be reduced to such an extent that methane begins to escape oxidation and accumulates in the atmosphere as on Titan. John Curtis |
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![]() Ward, working with UW biologist Raymond Huey and UW radiologist Kevin Conley, believes that breathing system, still found in today's birds, made the Saurischian dinosaurs better equipped than mammals to survive the harsh conditions in which oxygen content of air at the Earth's surface was only about half of today's 21 percent. Is there any way to know if the atmospheric pressure has always been 14.7 psi, or if it has varied widely over the eons? Venus, a planet slightly smaller than Earth, has an atmosphere 90 times the pressure at the surface than Earth's. Which would imply that Earth could hold an atmosphere that heavy, if the CO2 wasn't sequestered as limestone (IIRC) in our oceans. So there might have been a time where Earth's atmosphere was at say 30 psi, half being CO2, and the rest the N2 and O2 and the usual other stuff. After a big round of volcanos. Or just more N2 with the extra CO2 mopped up by the oceans? That would make it easier for those flying reptiles to fly..... |
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Ron Baalke wrote in message
... http://www.washington.edu/newsroom/n...ve/k103103.htm l University of Washington FOR IMMEDIATE RELEASE FROM: Vince Stricherz 206-543-2580 DATE: Oct. 31, 2003 Ultra-low oxygen could have triggered mass extinctions, spurred bird breathing system Recent evidence suggests that oxygen levels were suppressed worldwide 175 million to 275 million years ago and fell to precipitously low levels compared with today's atmosphere, low enough to make breathing the air at sea level feel like respiration at high altitude. Now, a University of Washington paleontologist theorizes that low oxygen and repeated short but substantial temperature increases because of greenhouse warming sparked two major mass-extinction events, one of which eradicated 90 percent of all species on Earth. In addition, Peter Ward, a UW professor of biology and Earth and space sciences, believes the conditions spurred the development of an unusual breathing system in some dinosaurs, a group called Saurischian dinosaurs that includes the gigantic brontosaurus. Rather than having a diaphragm to force air in and out of lungs, the Saurischians had lungs attached to a series of thin-walled air sacs that appear to have functioned something like bellows to move air through the body. Ward, working with UW biologist Raymond Huey and UW radiologist Kevin Conley, believes that breathing system, still found in today's birds, made the Saurischian dinosaurs better equipped than mammals to survive the harsh conditions in which oxygen content of air at the Earth's surface was only about half of today's 21 percent. And how did this determination get made? This 'theory' is completely circular. Because saurians have countercurrent lungs, the oxygen level must have been lower. And saurian lungs needed to be countercurrent, because the oxygen was lower. Oxygen concentrations are controlled and limited by wildfires. At about the current levels. A significantly lower oxygen level would only result from a multimillion year loss of phytoplankton in the ocean. "The literature always said that the reason birds had sacs was so they could breathe when they fly. But I don't know of any brontosaurus that could fly," Ward said. That isn't what the literature "always says." See Bakker. "However, when we considered that birds fly at altitudes where oxygen is significantly lower, LOL! The oxygen ratio is the same at all altitudes. we finally put it all together with the fact that the oxygen level at the surface was only 10 percent to 11 percent at the time the dinosaurs evolved. Again, how did this become a "fact?" "That's the same as trying to breathe at 14,000 feet. If you've ever been at 14,000 feet, you know it's not easy to breathe," he said. Ward believes low oxygen and greenhouse conditions caused by high levels of methane from intense volcanic activity Volcanic activity does not remove oxygen. {snip} Ward said mass spectrometer readings on fossil material, as well as the extinction pattern for fossils in rock outcrops collected from the time of the two extinctions, indicates the events were drawn-out affairs and did not happen suddenly, as they would have with an asteroid impact. Mass spectrometer readings on fossil material cannot indicate drawn-our affairs. Though extinction patterns can indicated this (again, see Bakker). In addition, he said it is known which types of creatures, and which breathing systems, best survived the extinction events. The extinction events also affected the ocean-dwellers. Not just lung-users. {snip} -- greywolf42 ubi dubium ibi libertas {remove planet for return e-mail} |
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Dear greywolf42:
"greywolf42" wrote in message ... Ron Baalke wrote in message ... .... "However, when we considered that birds fly at altitudes where oxygen is significantly lower, LOL! The oxygen ratio is the same at all altitudes. The relative concentration is the same, but the pressure, and hence the amount of oxygen per "breath" is decreased. Remember that we have to wear breathing apparatus when climbing to altitude. And we don't have to output near as much continuous power/pound as birds do (when not coasting). David A. Smith |
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Leafing through alt.sci.planetary, I read Robert Casey's message of Sun,
2 Nov 2003: So there might have been a time where Earth'satmosphere was at say 30 psi, half being CO2, and the rest the N2 and O2 and the usual otherstuff. That would make it easier for those flying reptiles to fly..... Yes, that's an interesting hypothesis - they learn to fly when flying is easier. However, if the O2 pressure was the same as it is now, the breathing would not have been any more difficult, if I understand these things correctly. But, of course, there is no overriding reason why both much higher total pressure and much lower O2 pressure should not have occurred sometime in the past, not necessarily co-incidentally. -- ,---. __ E-mail replies: please simply reply _./ \_.' without altering the subject line '..l.--''7 unless this newsgroup message is |`---' over two months old. If you do meet | Peter Munn problems, please mail to newsreply | Staffordshire UK @pearce-neptune... instead. |
#8
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Ron Baalke wrote in message
... http://www.washington.edu/newsroom/n...ve/k103103.htm l "However, when we considered that birds fly at altitudes where oxygen is significantly lower, In article , "greywolf42" writes: LOL! The oxygen ratio is the same at all altitudes. What does the oxygen ratio have to do with anything? What do you think happens to the partial pressure? Have you ever actually been to high altitude? How easy was it to breathe? Or exercise? we finally put it all together with the fact that the oxygen level at the surface was only 10 percent to 11 percent at the time the dinosaurs evolved. Again, how did this become a "fact?" Why don't you look it up and tell us? Ward believes low oxygen and greenhouse conditions caused by high levels of methane from intense volcanic activity Volcanic activity does not remove oxygen. I read the sentence wrong, too. It was sloppy, but read it again. It isn't saying the volcanic activity caused low oxygen, only that the low oxygen was simultaneous in time with high methane, the latter caused by volcanic activity. -- Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.) |
#9
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![]() "greywolf42" wrote in message ... Ron Baalke wrote in message ... http://www.washington.edu/newsroom/n...ve/k103103.htm l University of Washington FOR IMMEDIATE RELEASE FROM: Vince Stricherz 206-543-2580 DATE: Oct. 31, 2003 Ultra-low oxygen could have triggered mass extinctions, spurred bird breathing system Recent evidence suggests that oxygen levels were suppressed worldwide 175 million to 275 million years ago and fell to precipitously low levels compared with today's atmosphere, low enough to make breathing the air at sea level feel like respiration at high altitude. Now, a University of Washington paleontologist theorizes that low oxygen and repeated short but substantial temperature increases because of greenhouse warming sparked two major mass-extinction events, one of which eradicated 90 percent of all species on Earth. In addition, Peter Ward, a UW professor of biology and Earth and space sciences, believes the conditions spurred the development of an unusual breathing system in some dinosaurs, a group called Saurischian dinosaurs that includes the gigantic brontosaurus. Rather than having a diaphragm to force air in and out of lungs, the Saurischians had lungs attached to a series of thin-walled air sacs that appear to have functioned something like bellows to move air through the body. Ward, working with UW biologist Raymond Huey and UW radiologist Kevin Conley, believes that breathing system, still found in today's birds, made the Saurischian dinosaurs better equipped than mammals to survive the harsh conditions in which oxygen content of air at the Earth's surface was only about half of today's 21 percent. And how did this determination get made? This 'theory' is completely circular. Because saurians have countercurrent lungs, the oxygen level must have been lower. And saurian lungs needed to be countercurrent, because the oxygen was lower. Oxygen concentrations are controlled and limited by wildfires. Assumping that there is enough fuel to burn on land to significantly lower the atmospheric concentrations. There is no evidence that this happened in the Permian. Oxygen levels are also controlled by the carbon cycle, i.e., sequestation in carbonates. At about the current levels. A significantly lower oxygen level would only result from a multimillion year loss of phytoplankton in the ocean. "The literature always said that the reason birds had sacs was so they could breathe when they fly. But I don't know of any brontosaurus that could fly," Ward said. That isn't what the literature "always says." See Bakker. "However, when we considered that birds fly at altitudes where oxygen is significantly lower, LOL! The oxygen ratio is the same at all altitudes. A 21 percent oxygen ratio in a rarified atmosphere does not make breathing as easy as a 21 percent oxygen ratio at one atmosphere. Try driving up to Veil, Colorado from sea level and immediately running a mile. I'll call the parametics for you when you pass out. we finally put it all together with the fact that the oxygen level at the surface was only 10 percent to 11 percent at the time the dinosaurs evolved. Again, how did this become a "fact?" Its not that hard to figure out. One way is to look at the oxygen isotope ratios in sedimentary rocks or in fossils formed over time. This is done with a Mass Spectrometer, by the way. "That's the same as trying to breathe at 14,000 feet. If you've ever been at 14,000 feet, you know it's not easy to breathe," he said. Ward believes low oxygen and greenhouse conditions caused by high levels of methane from intense volcanic activity Volcanic activity does not remove oxygen. Since there have been no volcanic eruptions in modern times of the scale that has happened in the geologic past, I would say that that assumption is misleading, to say the least. I'd also have to ask from where you get this assumption? Ward said mass spectrometer readings on fossil material, as well as the extinction pattern for fossils in rock outcrops collected from the time of the two extinctions, indicates the events were drawn-out affairs and did not happen suddenly, as they would have with an asteroid impact. Mass spectrometer readings on fossil material cannot indicate drawn-our affairs. Though extinction patterns can indicated this (again, see Bakker). Have you ever done GC/MS before? Have you ever read lab results of GC/MS readings? If you have, then you cannot possibly credibly make this statement. In addition, he said it is known which types of creatures, and which breathing systems, best survived the extinction events. The extinction events also affected the ocean-dwellers. Not just lung-users. Yes it did. And your point is? What effect do you think a lower oxygen level in the atmosphere would have on the oceans? |
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On Sun, 9 Nov 2003 02:07:39 -0500, "George" wrote:
"greywolf42" wrote in message ... Volcanic activity does not remove oxygen. Since there have been no volcanic eruptions in modern times of the scale that has happened in the geologic past, I would say that that assumption is misleading, to say the least. I'd also have to ask from where you get this assumption? According to the estimates I've seen, up to 10 teratons of methane could have been released at the end of the Permian, which would soak up ~40 Tt of oxygen. This sounds like a lot, but if I haven't made a mistake in my calculations, the total amount of oxygen in the atmosphere ~= 1000 Tt, so it wouldn't be significantly dented. Am I missing something here? -- "Sore wa himitsu desu." To reply by email, remove the small snack from address. http://www.esatclear.ie/~rwallace |
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