Estuary

water · coast · ecosystems

Mixing waters. Estuaries happen where rivers flow into the ocean and freshwater bumps into saltwater. The two waters swirl together in a special blend that's part fresh and part salty, called brackish water.

Super fertile zone. All those mixed waters bring tons of nutrients from the river and ocean, making estuaries some of the richest habitats on Earth. Fish, birds, and countless creatures thrive here because there's so much food.

In-between world. Estuaries are transition zones where river life meets ocean life. They're shaped by both freshwater currents flowing downstream and ocean tides flowing back in, creating a unique ecosystem that belongs to both worlds.

Common and important. You can find estuaries around the world wherever rivers meet the sea. Many cities grew up around them because estuaries are full of fish and made great harbors for ships.