Estuaries are rich in biodiversity. Organisms that live in estuaries are uniquely adapted to their brackish water. The estuarine crocodile, the largest reptile in the world, is an apex predator native to tropical estuaries of Australia and Southeast Asia. Estuarine crocodiles are equally adapted to survive in saltwater and freshwater ecosystems.

Photograph by Sam Abell

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estuary Encyclopedic Entry

Best For
6 - 12 and up

Geography, Science

Appropriate For

  • Educators
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An estuary is an area where a freshwater river or stream meets the ocean. When freshwater and seawater combine, the water becomes brackish, or slightly salty.