Answer card
Why is the sea salty?
Want to guess first?
Write a guess down before you look, and you will notice what surprises you. You can’t get it wrong.
What we know
- True: “Rainwater that falls on land is slightly acidic, so it erodes rocks. This releases ions that are carried away to streams and rivers that eventually feed into the ocean.” NOAA Ocean Service — Why is the ocean salty?
- True: “Some ocean salts come from underwater volcanic eruptions, which directly release minerals into the ocean.” NOAA Ocean Service — Why is the ocean salty?
- True: “The average salinity is about 35 parts per thousand. Stated in another way, about 3.5 percent of the weight of seawater comes from the dissolved salts.” NOAA Ocean Service — Why is the ocean salty?
- True: “Two of the most prevalent ions in seawater are chloride and sodium. Together, they make up around 85 percent of all dissolved ions in the ocean.” NOAA Ocean Service — Why is the ocean salty?
What we made simpler
“Salts” here means many minerals dissolved in the water, not only the salt on your table (which is sodium and chloride).
Still open
How salty the very first oceans were, billions of years ago.
Next why
If rivers carry salt to the sea, why doesn’t river water taste salty?
DepthQuest — Ocean Chemistry →Try it
Written by people and checked against the sources named beside each line. All answer cards