[geoffthrob (OP)]

When sea water evaporates what happens to the salt? Does the salt build up at the bottom of the ocean? Are the oceans becoming more salty as times goes on? Thanks for your help.  []

[Kryptid]

Don't forget that the water that leaves the ocean in the form of evaporation also returns to it in the form of rain and river run-off.

[Bass]

The salt remains in the ocean.  The concentration may or may not increase, depending on the influx of fresh water and precipitation of salts from the ocean.  Different oceans have different salinityies- small bodies of water with no outlets can have very high salinities (Dead Sea, Great Salt Lake).  The Mediterranean, with high evaporation rates, little circulation and low influx of fresh water, is more salty than the other oceans.