Ultra-Low Oxygen Could Have Triggered Mass Extinctions, Spurred Bird Breathing System

http://www.washington.edu/newsroom/n...e/k103103.html

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.

"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. "However, when we considered that birds fly at altitudes where
oxygen is significantly lower, 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.

"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 are likely culprits in mass
extinctions that occurred about 250 million years ago, at the boundary
between the Permian and Triassic periods, and about 200 million years ago,
at the boundary between the Triassic and Jurassic periods. He will make a
presentation on the topic Tuesday at the American Geological Society annual
meeting in Seattle.

The Permian-Triassic extinction is believed to have eradicated 90 percent of
all species, including most protomammals, a group of mammal-like reptiles
that were the immediate ancestors of true mammals. The Triassic-Jurassic
extinction killed more than half the species on Earth, with mammal-like
reptiles and true mammals, which evolved during the Triassic Period, hit
particularly hard. But dinosaurs, which also evolved between the two
extinctions, had little problem with conditions during the Triassic-Jurassic
extinction.

"The seminal observation is that dinosaurs skated across the second of these
mass extinctions, actually increasing in number as they went along, while
everything else was dropping around them," Ward said.

Scientists know of five mass extinction events in Earth's history, but a
cause has been widely agreed upon for only one - the episode at the end of
the Cretaceous Period 65 million years ago, when the impact of an asteroid
is believed to have brought the demise of the dinosaurs. Such impact also
has been suggested as the cause of the Permian-Triassic and
Triassic-Jurassic extinctions, but geologists have yet to unearth any
indisputable evidence of such an impact, and there is no conclusive evidence
of what caused either of the events.

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.

In addition, he said it is known which types of creatures, and which
breathing systems, best survived the extinction events. The same breathing
systems are still present in birds, which are known to fare well at high
altitudes, where oxygen levels are substantially lower than at the surface.

"The reason the birds developed these systems is that they arose from
dinosaurs halfway through the Jurassic Period. They are how the dinosaurs
survived," he said.

###

For more information, contact Ward at (206) 543-2962 or

"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

"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

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.....

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}

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

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
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| Peter Munn problems, please mail to newsreply
| Staffordshire UK @pearce-neptune... instead.

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.)

"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?

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