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marine diving mammals

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.
C

cliffgollus

New Member
Feb 22, 2003
32
4
0
Hi all,

I enjoyed Eric's current article on why marine diving mammals can go so long, so deep. I do not know if there is a mechanism to have him field questions so will put this in the forum. Question; is there any record of seals suffering SWB? If not, any thoughts why? The small lung volume was cited as needed to prevent nitrogen narcosis and getting bent, but doesn't blood (and tissue) also carry dissolved nitrogen? And why doesn't the oxygen become toxic at such extreme depth?

Thx, Cliff
 
Reactions: loopy
Hi!

You can contact Erik directly by clicking on the "email" link on the article under his photo. This will allow you to email him directly. In the meantime i'll contact him and see if he can get you a response that I can post here.

Cheer!
 
I might be able to answer some of the questions.

Seals SWB: There have been some cases of seals blacking out when they cannot find a breathing hole under the ice. This is not really shallow water blackout, but just blackout. The shallow water has nothing to do with it. The seals die when this happens.

High amounts of dissolved nitrogen occur when the ppN2 in the lungs is huge, and then the blood flows past the lungs/aveoli, and absorbs the N2. If the lungs are collapsed, there is no gas exchange from lungs to blood, so high pressures of N2 are never exposed to the blood, and thus the blood does not absorb N2 and cannot carry the N2 to the tissues either.

O2 toxicity works the same as the N2. Collapsed lungs prevent gas exchange from the lungs to the blood, preventing huge amounts of O2 to dissolve in the blood.

In short, collapsed lungs prevent all types of toxicities and narcosis, and collapsed lungs also prevent DCS and all gas-pressure related anomalies.


Eric Fattah
BC, Canada
 
Here is the first part of Erik's answer:
 
Thanks for both answers, especially the idea of a "conservative" dive to give room for evading predators, etc - my kind of conservative!

One other thing Eric mentioned was the theoretical limit to how deep someone can go, and then gave the example of Pippin blasting past it. I read somewhere a theory that on very deep dives, Pippin's lungs avoided being "squeezed" by filling with plasma. There was no data presented to support this, and such a thing sounds very much like pneumonia. Any thoughts on how divers exceed the theoretical limits?

Thx, Cliff
 
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