Scientists say whales were bent!!

[jiveturkey]

Whales getting bent? I don't understand how this is possible. I'm pretty sure they weren't breathing compressed gas.

Check out the link: http://www.globeandmail.com/servlet/story/RTGAM.20031008.uwhale09/BNStory/International/

 

[crazed_dolphin]

They weren't bent.....they had similar symptoms that humans get when we get DCS. The sonar is believed to be the cause of the nitrogen bubbles in the blood stream.

 

[Diver0001]

jiveturkey once bubbled...
Whales getting bent? I don't understand how this is possible. I'm pretty sure they weren't breathing compressed gas.

Check out the link: http://www.globeandmail.com/servlet/story/RTGAM.20031008.uwhale09/BNStory/International/

This is an interesting one for Dr. Deco.

Nitrogen levels in the tissues will increase as a result of freediving (what whales in fact are doing). This happens because the air in your lungs will compress as you go deeper and the nitrogen partial pressures will increase. For human freedivers it isn't much of a problem because they dive short and shallow as compared to whales. But if you're diving 100 metres deep (or deeper) and 1/2 hour long (or longer) then you're in decompression territory.

The link with the sonar wasn't about nitrogen uptake, though. It's a well known fact about bubble forming that aggitation (shaking or vibrating) stimulates bubble formation. Sonar is vibration and vibration leads to extra bubble formation so where as a whale might not have gotten DCS when just freediving, it might very well occur when exposed to sonar vibrations.

Hope that explains.

R..

 

[jiveturkey]

The whales are diving on a single breath taken at the surface. The expanding gas is only going to get as large as it was at the surface. It shouldn't matter how deep you go.

 

[JimC]

That logic works for lung over expantion injuries.

DCS is a completely diferent monster and there is more than enough N2 in a single breath of air to bend a human if they go down deep enough, long enough and come up fast enough.

Humans can't sustain life long enough on a single breath to realisticaly do it mind you. Whales should be able to easily achevie serious N2 loads. I would have to guess they are more tolerant and what would kill a human does nothing to a whale.

They might also be doing a lot of inwater recompresion therapy on there repetative dives! I wonder if whales typicaly do many shalow dives after deeper ones?

 

[CD_in_Chitown]

JimC once bubbled...
Humans can't sustain life long enough on a single breath to realisticaly do it mind you.

Strange that it would be documented in people then, check out the facts here

 

[saying]

JimC once bubbled...
I wonder if whales typicaly do many shalow dives after deeper ones?

Interesting idea.

As I understand it whales hang pretty close to the surface most of the time, breathing pretty regularly. (Of course, close to the surface for a 300 ton aquatic animal means somewhere from 1 - 30 feet or so.) Generally whales dive deep to hunt or flee.

I wonder if this behavior is evolution, an example of having weeded out the bent ones all those years ago?

 

[JimC]

I was refering to a single breath hold dive. These guys are doing repetative, extreem free dives.

Just look at what the world record holders are doing. Hundreds of feet, passed lung crush depth, on a sled and then accending on inflated baloons.

My question is what about Nitrogen Narcosis and O2 Tox. These guys are WAY passed where sane divers go on air.

cd_in_SeaTac once bubbled...


Strange that it would be documented in people then, check out the facts here

 

[Diver0001]

jiveturkey once bubbled...
The whales are diving on a single breath taken at the surface. The expanding gas is only going to get as large as it was at the surface. It shouldn't matter how deep you go.

Right. But I think you might have missed the point.

Under water the ambient pressure increases and it squishes your lungs with whatever air they had in them when you took your last breath at the surface. This squishing actually compresses the air in your lungs (and ears and whatever other air-spaces you have) so in fact you have compressed air in your lungs even when you're freediving. Your lungs will not be as full as they would have been on scuba but the air is compressed nevertheless.

You can visualise this by thinking of what happens to a balloon when you take it under water. As you go deeper it gets smaller and the air inside gets compressed.

So getting to the point, the squished air is compressed and compressed air, as you know, will lead to nitrogen uptake in your system as you descend. This is where "how deep" and "how long" come into the equation.

Hope this clarifies things a bit.

R..

 

[saying]

Diver0001 once bubbled...

So getting to the point, the squished air is compressed and compressed air, as you know, will lead to nitrogen uptake in your system as you descend. This is where "how deep" and "how long" come into the equation.

ie: The air in your lungs when freediving to 100fsw is at the 4ATA you would have breathed from a bottle, there's just not enough of it to keep you lungs at the normal volume.

Thereby, the reason freedivers do not usually get bent is not because they aren't breathing compressed air (because if breath is defined as metabolizing by using... then they are) it's because they aren't spending anywere near enough time, in normal circumstances, to get anywhere near NDLs.

Out of curiosity: are there phsyiological dangers for someone to freedive to 100 feet, exhale, and then take a breath from a reg sitting there waiting for them? That is, is there a risk in changing lung volume that quickly?