The primary source of dissolved salt in the oceans, according to scientific understanding, is the gradual erosion of rocks on land.
The Primary Source: Rocks on Land
Rocks on land are the major source of salts dissolved in seawater. This process occurs over vast periods as part of Earth's natural cycles.
Here's a breakdown of how this process, highlighted in the reference, contributes salts to the ocean:
- Rainwater Erosion: Rainwater is naturally slightly acidic due to dissolved carbon dioxide from the atmosphere. When this acidic rainwater falls on land, it acts as a weak solvent.
- Rock Weathering: As rainwater flows over and through rocks, it causes them to erode. This erosion releases various ions – electrically charged atoms or molecules that make up the salts.
- Transport to the Ocean: These dissolved ions are then carried away by surface runoff and groundwater. They flow into streams and rivers, which act as natural transport systems, eventually feeding into the vast ocean basins.
Think of rivers constantly delivering a small but steady supply of these dissolved rock components into the sea. Over millions of years, this continuous input has accumulated the immense amount of salt found in the world's oceans.
This natural process of weathering and transport is fundamental to the ocean's salinity.
