Does an increase in the salinity of seawater result in an increase or decrease in density?
Addition of salt to water definitely increases the MASS of the solution, while only marginally affecting volume.
As the water becomes more saline, a given object will become more buoyant in the water......
For a fun simple experiment take a 12 oz can of diet soda and a 12 oz can of regular soda with sugar. The diet soda will float and the regular soda will sink.
Adding a solute adds to the density of the solution. The more salt that is added to the water the greater the density will be.
The dead sea has water coming in carrying salts and no water going out. This causes an increase in the salinity of the dead sea. It is very easy to float in the dead sea because of the increased density of the water due to the dissolved salts.