Water is not very compressible; even at the bottom of the ocean a kilogram of plain water still takes up 0.982 liters of volume (compared to 1 liter at the surface).
However, actual ocean water is saline (salty), and the salinity of the ocean varies widely. Dissolved salt makes ocean water more dense than pure water; and the more salt there is, the denser it is. That’s why it’s easier to float in the ocean than in a freshwater lake.
Typically, the water at the bottom of the ocean is slightly less salty than the water at the surface. This is because evaporation happens at the surface.
Water is not very compressible; even at the bottom of the ocean a kilogram of plain water still takes up 0.982 liters of volume (compared to 1 liter at the surface).
https://en.wikipedia.org/wiki/Properties_of_water#Compressibility
However, actual ocean water is saline (salty), and the salinity of the ocean varies widely. Dissolved salt makes ocean water more dense than pure water; and the more salt there is, the denser it is. That’s why it’s easier to float in the ocean than in a freshwater lake.
Typically, the water at the bottom of the ocean is slightly less salty than the water at the surface. This is because evaporation happens at the surface.