Salinity (Geography)

[Aiezsedai]

Hi,

My question is about salinity of seas. Why is the Red Sea (45 promilles) saltier than the World Ocean (35 promilles)? And why is the Dead Sea even saltier - 67 promilles? What are the natural causes of these differences?

[gonelli]

I would put both instances down to evaporation, or some other process relating to it.

 

Doing a search on both seas does reveal information on reasons for the different salinities, probably best to start there.

[CaptainPanic]

How does the salt get into the sea? That's the question you want to answer.

[npts2020]

It makes sense for the Dead Sea to increase salt concentration from evaporation and reduction of tributary input since it is fairly isolated, the Red Sea has about a 100k wide connection to the Gulf of Aden arm of the Indian Ocean, which makes me skeptical that evaporation could be the main cause there.

[gonelli]

the Red Sea has about a 100k wide connection to the Gulf of Aden arm of the Indian Ocean, which makes me skeptical that evaporation could be the main cause there.

 

I actually was thinking the same thing when I first read the OP. Wikipedia (while I don't completely trust it) mentions that "due to the effects of the water circulation pattern, resulting from evaporation and wind stress. Salinity ranges between 3.6 and 3.8%." I'm going to try and see if I can find a more in depth explanation somewhere else, but that could be a good starting to point for explaining the salinity level.

 

As for why there is salt in sea water in the first place... there's a lot of salt around, and plenty of water for it to dissolve into.