Hot answers tagged underwater
Yes, according to calculations presented here and here the conclusion is that: The O2 diffusion coefficient in saturated air (15% oxygen) is 5,700 to 10,800 times greater than in water (60°C and 20°C respectively). And here is a paper using this difference to investigate the transfer of O2 through the tracheal system of a click beetle.
I'd say that unihemispheric sleep and adaptations like it really are sleep - the brain activity on one side of the brain gives a characteristic sleep pattern. It certainly must satisfy the needs of an aquatic mammal like a dolphin or a whale since they have to be partially conscious to breathe by surfacing regularly. It does seem to affect the brain ...
This answer may not be professional, but I think that if the marine life were born and raised in a reef surrounded by hard water they would most likely adapt to it and be fine. This is why if a human were to be raised on mars, he would find it impossible to walk on earth as the difference in gravity would be too much.
I suppose that it depends on how sleep is defined. If we define it a a mechanism by which the brain repairs itself in an altered state, then, yes they do indeed sleep. Just not with all of their brain at once.
These are different things. Nitrogen Narcosis or more commonly Gas Narcosis is the narcotic effect of gasses like Oxygen and Nitrogen under pressure. The effects are most prominent under 30m and commercial/technical dives doing dives to 40/50m on air tend to experience the effects most. (Narcosis is managed by adding an inert gas - in most gases Helium - ...
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