On: Two days in an underwater cave running out of oxyg...

[stingraycharles]

This probably is a stupid question, but wouldn't the salty seawater be lighter than the rain water, and thus be at the surface ?

[cr1895 → stingraycharles]

Salty water is quite literally more dense than fresh water. Average seawater is 1025 kg/m^3, pure water is nominally 1000 kg/m^3.

Somewhat related video: dense brine that doesn't freeze in Arctic sea ice sinks rapidly through liquid seawater below

https://youtu.be/WyWn1XJ9kTE

[stingraycharles → cr1895]

Oh geez, you're absolutely right, I don't know what I was thinking. I probably needed my morning coffee.

[x2398dh1 → stingraycharles]

It's OK, stingrays like you aren't expected to know about polar regions and super cold water.