Life in an Estuary — Reading Comprehension

An estuary is not just a place where rivers meet the ocean—it is also one of the busiest ecosystems on Earth. The mix of freshwater and saltwater creates a special environment called brackish water. Many species can live only in estuaries because they are adapted to these conditions.

The structure of life in an estuary is diverse. Tiny plankton float in the water, serving as food for small fish and crabs. Shellfish such as clams and oysters attach to the muddy bottom. Marsh grasses and mangroves grow along the edges, providing shelter for birds and insects. Each part of this structure supports another, forming a web of life.

The function of estuaries is critical for the environment. They act as filters, cleaning water by trapping sediments and absorbing pollution before it reaches the ocean. Estuaries are also “feeding stations” for migrating birds and “rest stops” for fish traveling between rivers and seas.

Humans benefit in many ways too. Estuaries support fisheries, provide jobs, and are popular spots for recreation such as boating and birdwatching. 

However, they are fragile. Too much pollution, loss of marsh plants, or rising sea levels can damage these ecosystems.

Fun Fact: The largest estuary in the United States is the Chesapeake Bay, which supports more than 3,600 species of plants and animals!

What is brackish water?

What do plankton provide?

Why are marsh grasses important?

Which animal attaches to the bottom?

How do estuaries act as filters?

Why are estuaries “rest stops”?

What threatens estuaries?

Largest U.S. estuary is?