Mon Prof Augmenté
How a Lagoon Is Born
Sea currents carry sand along the coast and drop it across the opening between two hills. Little by little, the sand builds a bar that rises above the water and traps a pocket of sea behind it, called a lagoon.
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In the picture
- A current flows along the shore carrying sand
- Sand piles up under the water in a long ridge
- The ridge rises above the waves as a sand bar
- Sea water trapped behind the bar becomes a lagoon
Examples
- A sandbar you can walk out to at low tide forms the same way
- The Venice lagoon in Italy is kept apart from the sea by long sandy islands
Key takeaways
- A lagoon is shallow sea water separated from the open sea by a strip of sand
- Currents take many years to build a sand bar
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