Now that I think about it, I've scuba dived to 130 feet and it didn't feel any different to me than being at 10 feet. The only reason I didn't go deeper is because the depth gauge, divermaster, and training told me not to go deeper, and not because I was feeling the pressure.
The effects of that pressure can change the way that our bodies interact with the gases disolved in our blood.
Nitrogen/Gas narcosis occures (with a normal air mixture) due to the higher partial pressure of those gases in your blood and cause an effect similar to inhaling nitrous oxide.
At even higher pressures, oxygen (in standard air mixtures) reach a partial pressure in your blood that becomes toxic, can cause severe damage and trigger seizures. (Which at depth will likely be fatal.)
Drivers who go deep must switch between different air mixtures as they descend and ascend through different pressure. This "tech" diving can be very dangerous and requires detailed training and planning to do safely.
I am no biologist but would imagine that animals who dive deep have developed specialized metabolisms to deal with the changes in partial pressure of gases as they dive deeper. (Edit: it looks like diving air breathers tend to have mechanisms to reduce the gas exchange between their lungs and blood so that the partial pressure of gases in their blood doesn't go up as they go down)
Decompression is a different issue and has to do with how these high partial pressures of gases (especially nitrogen) work their way out of tissues without coming out of solution and forming air bubbles.
"Feeling" changes in pressure depends on air space that can't equalize that pressure. One reason masks (which cover the nose) are used rather than goggles (which don't) is so that you can add air from your lungs to the mask and equalize the pressure. Otherwise you could give yourself a black eye or suffer a severe injury.
A fish's swim bladder is full of air that's been extracted from the water. As long as they don't go up and down too fast, they'll be fine at whatever depth.
But the other side of the equation is the partial pressures of various gasses dissolved in the blood. Humans experience nitrogen narcosis and oxygen toxicity just from breathing regular air and need special mixtures, fish need special biology to cope.
I would hazard a guess that it has to do with where food is.
Suddenly bringing up a deep water fish would make it explode. every 33ft up the volume of air doubles.
Hence that rule of diving of never holding your breath and continuously letting the air out as you surface.
What I find incredible that a seal could dive that deep, the volume of air at that depth would be a tiny fraction of the volume of air at the surface. It is as if its lungs were completely collapsed and empty.
I could be missing something, but I don't think this is quite correct.
Coming up from the first 33ft (10 meters) of depth, the pressure would go from two bars to one, or half, so the volume would double.
But any deeper, the ratio of pressure between the current depth and ten meters shallower isn't double, it's n/(n - 1).
Every ten meters the volume goes down like so 1, 1/2, 1/3, 1/4, 1/5
PS. Fish could still explode tho
I'm not in general willing to be a guinea pig for genetic manipulation, but toothed whale myoglobin and being able to dive with empty lungs for half an hour or 45 minutes? Sign me up.
: Mirceta, S., Signore, A. V., Burns, J. M., Cossins, A. R., Campbell, K. L., & Berenbrink, M. (2013). Evolution of mammalian diving capacity traced by myoglobin net surface charge. Science, 340(6138), 1234192–1234192. http://doi.org/10.1126/science.1234192
Also, this has nothing to do with decompression sickness (aka 'the bends'). That is to do with dissolved gases in the blood which turn into bubbles when the pressure is lowered.
> Air is forced from the lungs during a dive and into the upper respiratory passages, where gases cannot easily be absorbed into the bloodstream. This helps protect the seal from the bends.
Dissolved gases dropping out of solution and forming bubbles is literally decompression sickness.
and for clarity: 'forcing air into respiratory cavities in the skull' would not prevent the bends.
When you dive to 50m, the feeling of "being dizzy" happens when diving on air. This is due to Nitrogen narcosis. To minimise this, in technical diving, helium is added to the mix, to reduce the percentage of nitrogen and minimise the narcosis.
Going down to 332m, as you correctly say subjects you to a pressure of 34 Bar. To dive this deep you need to be breathing 4% Oxygen, maximum (compared to 21% that is in air we breathe at the surface). At this level, making the mix needs to be extremely precise and you need to be sure your instruments are properly calibrated, as a 5% mix can potentially kill you at that depth.
Ascending is just as dangerous since you now have highly compressed gas bubbles throughout your body. There are different models you can follow to manage decompression, but it’s far from settled science. Both individual variation and situational factors can affect it greatly.
> After almost five hours inside their tiny 6ft 4in cabin, the duo touched down on the sea floor at 36,000ft. [...] They spent 20 minutes there identifying the source of the explosive sound – a cracked acrylic window towards the back of the sub's entrance tunnel caused by the immense pressure of the water surrounding them. Due to their extreme conditions, they wouldn’t be able to fix it until they had made the long journey back to land through the silent abyss.
They did still continue despite the sound and vibration, of course.
The page is using up 15-20% CPU and GPU when it is the active tab even when not scrolling. That seems unexpected and unfortunate.
(I noticed because by the time I got to 3400 meters, my laptop's fans became audible.)
Regardless, fun and interesting webpage!
I wish some bored billionaires would take up the challenge and pump their billions into deep sea research. Like some others do for space exploration.
> "So little is known about life in these deep environments. Almost every expedition uncovers something new."
And I'm in that fraction, muahahahaha. ;-)
"One final note about life in the abyss: not all intruders from the lighted world are ROVs
or submarines. A southern elephant seal tagged by Census project TOPP recently dove
down 2,388 meters (~1.5 miles) from the surface. At that depth, water pressure is
roughly equal to 240 times the air pressure at sea level. The human eardrum can rupture
at 10 meters"
Do this a few times and you will notice all species have the same “age”, assuming life today all descendent from a common ancestor. Yes, some of them have may have changed more or less in appearance, but that correlates poorly with genetic changes.
You can't say that a species is as old as it's ancestral species, because you're talking about two different species.
>2400 METERS DEEP
That one caught me off guard. I'm used to seeing stories (or "tales") of e.g. Sperm Whales accomplishing incredible dives like that. An elephant seal doesn't really seem to be tuned to that kind of performance dives.
One additional info that could be included is that of submarines and their depth rating.