The Deep Sea

Throughoutly enjoyed it. Thanks for the good work.

> 6000 m: "More people have been to the Moon than the Hadal Zone."

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."

Beautiful! A really important article about how we’re about to start mining these regions on an unprecedented scale: https://www.theatlantic.com/magazine/archive/2020/01/20000-f...

That isn't really accurate. You are "pressurized" by the water around you. When the air comes out of your air tank, it's volume is dictated by the pressure around you. (Edit: this pressurized air has a higher partial pressure of the constituent gases which causes them to be absorbed from your lungs into your blood and then into your other tissues which eventually changes the partial pressure of the gases disolved in them, the reverse happens as you ascend and theses gases work their way back out into your blood and then lungs.)

"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.

When diving (as opposed to using a submarine), your body reaches the same pressure as the water surrounding it so there is no differntial to feel.

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.