Why Is the Ocean Salty?
And is it getting saltier over time?
Growing up on an island, I’ve swallowed my fair share of seawater. And yuck, is it salty! When I later learned that urine is also salty, I became horrified and started looking at the bathing tourists with suspicion. Are they the source of that briny taste?
But since seawater made me gag enough already, I didn’t want to further inquire, lest my suspicion be confirmed. Eventually, however, my curiosity won out and I looked it up. Most online sources gave me this explanation:
Rainwater is slightly acidic and so when it falls on land, it slowly erodes rocks. This frees minerals from the rocks, which are then transported by streams and rivers to the ocean where, over millions of years, they accumulate, making the sea salty.
Even the US geological survey gives this as the main explanation.
But you know what? Although it sounds more sensible than my urine hypothesis, it’s just as wrong. Saying that the oceans are salty because of what rivers dump into them is like saying rivers transporting orange juice could produce, over millions of years, an ocean of tomato soup. It can’t. Rivers and oceans have different ingredients — they are not the same type of soup.
