water pressure

The water of seas/oceans should have a different state "salty"whereas for rives likes and cave water "fresh"

While swimming in salty state at Greater depths player will take damage from watt pressure for this there should be another bar (like Hunger or Heath) only visible while in water. 

Player will take damage below a certain sea level and will take damage every 7 seconds of 1.5 hearts with leather /gold or no armour. 1 heart with iron. Half heart with Netherite and diamond. And will take same damage as diamond or Netherite with acute armour but every 14 seconds. This can be effected using aqua affinity enchantments