The Salty Secret: Unraveling Why Sea Water is Salty, But Rivers Are Fresh

• Rainwater, slightly acidic from atmospheric carbon dioxide, erodes rocks on land, dissolving minerals like sodium and chloride.
• Rivers transport these dissolved minerals to the sea; river water remains fresh due to low mineral concentration and constant flow.
• The sea acts as a 'final collection point' where salts accumulate over billions of years, as there's no outlet for them.
• Evaporation removes pure water from the sea, leaving salts behind, continuously increasing salinity.
• Underwater hydrothermal vents and volcanoes also release minerals and salts directly into the sea, contributing to its saltiness.