Bone density underwater. Understanding the effects of Increased pressure vs Bouyancy

[manohman]

So you would expect that land creatures would have a greatest bone density with the strongest and heaviest bones, compared to animals living in the ocean.

And this makes sense since swimming is apparently really good on your joints. because there is less strain put on your bones underwater.

but underwater, or in the ocean, the pressure should be greater shouldnt it? So youd think that if there is greater pressure like at the bottom of the ocean, i.e. where submarines get crushed like soda cans in the movies due to the pressure,there would be greater strain on your bones?

Im guessing it has something to due with the bouyancy.

---

Members don't see this ad.

 

[amy_k]

The buoyant force and hydrostatic pressure are two different effects to consider in this context.

In the water the buoyant force acts upwards on the swimmer as their weight acts downwards, so the buoyant force takes some of the stress of gravity acting on the body away at all depths, and is experienced as an upwards force acting on the body.

The high pressure deep under the ocean surface is due to the large weight of the column of water above the submarine or deep-sea diver causing hydrostatic pressure. The diver still experiences a buoyant force and apparent 'weightlessness,' but the increase in hydrostatic pressure is experienced in the ears and lungs due to air in the body, which is at a different pressure to the total pressure in the water at that depth and needs to be equalized.