The saltiness of seawater, or ocean salinity, is mainly caused by the dissolution of mineral ions from rocks on land into water. Rainwater, slightly acidic, erodes rocks, releasing these ions. Over time, these ions are carried into the ocean by rivers and streams. The continuous cycle of evaporation, where water evaporates but the dissolved salts remain, further concentrates the salt in the ocean.
Additionally, volcanic activity at hydrothermal vents on the seafloor also contributes to ocean salinity. These vents release dissolved minerals, including salts, into the ocean.
Here's a simple breakdown:
- Rainwater: Slightly acidic, it erodes rocks on land.
- Erosion: Releases mineral ions, including salts.
- Rivers & Streams: Carry dissolved ions into the ocean.
- Evaporation: Water evaporates from the ocean, leaving salt behind.
- Hydrothermal Vents: Release dissolved minerals, including salts, into the ocean.
This process has been happening for millions of years, resulting in the salty ocean we know today.
