Why is the ocean salty? And why doesn’t it keep getting saltier and saltier? Let us explain in song.
So how does salt get into the ocean? It’s from erosion. Soil and rocks near lakes and rivers slowly break down. When they do, they drop bits of minerals into the water, and those minerals eventually flow to the ocean where they collect.
This leads to the next question — if these salts keep coming into the ocean why isn’t it getting saltier and saltier all the time? It’s because the salts are also being removed by mineral precipitation.
Mineral precipitation in the ocean happens when dissolved minerals come out of the salty solution and form solids again.
Some of these minerals that precipitate out fall to the ocean floor and end up forming sedimentary rocks, like gypsum.
This precipitation helps the ocean keep its balance. But there are regional difference due to differences in precipitation and evaporation. For instance, parts of the Atlantic are as high as 37 and parts of the Pacific are as low as 32. But the average is 35, and it’s been about 35 for millions of years.