Re: [GZG] Biology in a vacuum

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Gzg-l@lists.csua.berkeley.edu
http://lists.csua.berkeley.edu/mailman/listinfo/gzg-lIt's off-topic, but
have you seen anything on whales getting the bends?  The
article I saw
theorized high power sonar was scaring them causing them to surface too
quickly.

Roger Books

On 3/29/06, Beth.Fulton@csiro.au <Beth.Fulton@csiro.au> wrote:
>
> G'day,
>
> > Don't the deep diving sperm whales have air in
> > their lungs? Their lungs are probably
> > compressible, but they still have air no?
>
> For one Sperm whales don't go to the abyssal depths, they only go down
> 3000m. They also do this by having lungs that are (proportionally)
less
> than half those of terrestrial mammals, but they exchange much more
> efficiently (so while we manage a fairly small exchange of 15% on a
> breath they exchange upto 90%). They also have very high oxygen
binding
> as their red blood cells are larger. They also have 10 times the
> myoglobin. Moreover as a whale descends the lungs are compressed
(almost
> to the point of collapse) and what is there is pocketed into
> nonabsorptive parts of the lungs and nasal passages. A small trickle
> maybe allowed via shunts to vital organs. The muscles work off the
> myoglobin and can even go into heavy oxygen debt (which they work off
by
> breathing like crazy when they surface). They also tolerate CO2 build
up
> in the blood. Normal breathing and blood-oxygen transfer doesn't
resume
> until they're moving toward or are at the surface.
>
> Smaller deep diving mammals actually use the same tricks and go one
step
> further. They breath out or only take very very shallow breaths before
> they dive.
>
> SO basically whales do it by keeping air pockets to a minimum, which
is
> the way all deep sea creatures do it too. They don't have air filled
> bladders they have oil filled. Less pressure concerns that way, less
> equalisation issues for the degree of vertical movement they may do on
> short time scales.
>
> > Overall, you're still only dealing with 1
> > atmosphere of pressure which engineering wise is
> > trivial to contain.
>
> Its relative change that's important. For instance you get some of
your
> most dangerous diving accidents in the top metre of the ocean, because
> their the relative pressure is doubling, from there down the changes
are
> only incremental. So going from 1 atmosphere to no atmosphere isn't
> actually trivial for biological organisms.
>
> Cheers
>
> Beth
>
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