Why the Red Sea concentrates salt
The Red Sea lies in a hot, dry region, where strong sunlight drives rapid evaporation and rain is scarce. Rivers add little freshwater to offset that loss. When seawater evaporates, its water molecules escape into the air, but most dissolved salts stay behind. The remaining water therefore becomes more saline—the measure of how much salt it contains.
A narrow gateway keeps the balance
The Red Sea is not sealed off. It connects to the Gulf of Aden and the Indian Ocean through the narrow Bab el-Mandeb strait, where water flows in and out. That exchange carries salt away as well as bringing in less-salty water, keeping the sea from becoming ever more concentrated. Its salinity reflects the balance between intense evaporation, limited freshwater input, and that ocean exchange.
For travelers, the striking part is that this saltiness is produced less by a special source of salt than by what the climate removes: the sun takes water out, while the dissolved minerals remain.
