[extropy-chat] HISTORY: Solved & Unsolved Riddles

[Rafal Smigrodzki]

----- Original Message ----- 
From: "Hal Finney" <hal at finney.org>
To: <extropy-chat at lists.extropy.org>
Sent: Saturday, November 08, 2003 2:25 AM
Subject: Re: [extropy-chat] HISTORY: Solved & Unsolved Riddles


> I was interested to hear the discussion of why whales don't get the bends.
> However the explanation doesn't seem complete.  I believe that ordinary
> air, if compressed within the lungs, will dissolve to a greater degree
> in the blood, so the bends are possible even if you don't breathe
> compressed air.

### But the amount of air within the lungs of a whale must be minuscule
compared to the amount of air contained in a diver's bottle, at least if
divided by the volume of tissue in which the gas can dissolve in. The whale
carries most of his oxygen internally in the form of myoglobin, and doesn't
carry around a lot of gaseous nitrogen.

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>
> According to
> http://rbcm1.rbcm.gov.bc.ca/programs/whales/t-activity-5.html, whales
> have additional adaptations to prevent gases from being dissolved in
> their blood during dives, mechanisms to reduce the interface between
> air and blood.
>
> According to http://www.msnbc.com/news/977733.asp, a study reported
> in Nature last month suggested that some recent whale strandings after
> exposure to military sonars may have been caused by the animals getting
> the bends.  The author is quoted, "This new evidence from our study of
> marine mammal diseases in the U.K. challenges the widely held notion that
> cetaceans (marine mammals) cannot suffer from decompression sickness."
>
### But is it certainly the bends? I seem to recall reading about cavitation
as the postulated mechanism here.

Rafal