U.S. flag An official website of the United States government.
				Here's how you know we're official. **Official websites use .gov** A **.gov** website belongs to an official government organization in the United States.
 **Secure websites use HTTPS** A small lock or **https://** means you’ve safely connected to a .gov website. Share sensitive information only on official, secure websites.


Toggle navigation Toggle search National Ocean Service National Oceanic and Atmospheric Administration
 Search
					Search National Ocean Service


Home
				Ocean Facts

				Topics
					Explore All Topics 
                        Arctic 
                        Careers 
                        Economy 
                        Ecosystems 
                        Geodesy 
                        Hazards 
                        International
                        Navigation 
                        Observations 
                        Ocean 
                        Recreation 
                         Sea Level Rise 
                        Story Maps 
                        Tools
                
                			Education

				
				News
				Podcasts
				Video
				Images
				About Us


1. Home
2. Facts
3. What is an estuary?

**What is an estuary?**  The Estuary—where fresh and saltwater mix. It appears that your browser doesn't support HTML5 video.
						Here's a direct link to
							the video instead.
  **Estuaries: Where the River Meets the Sea**  Here's an overview in under two minutes. Transcript  Estuaries  and their surrounding wetlands are bodies of water usually found where rivers  meet the sea. Estuaries are home to unique plant and animal communities that have adapted to brackish water—a mixture of fresh water draining from the  land and salty seawater. However, there are also several types of entirely freshwater ecosystems that have many similar characteristics to the traditional brackish estuaries. For example, along the Great Lakes, river water with very different chemical and physical characteristics mixes with lake water in coastal wetlands that are affected by tides and storms just like estuaries along the oceanic coasts. These freshwater *estuaries* also provide many of the ecosystem services and functions that brackish estuaries do, such as serving as natural filters for runoff and providing nursery grounds for many species of birds, fish, and other animals. Estuaries are among the most productive ecosystems in the world. Many animals rely on estuaries for food, places to breed, and  migration stopovers. Estuaries are  delicate ecosystems. Congress created the  National Estuarine Research Reserve System to protect more than one million acres of estuarine land and water. These estuarine reserves provide essential habitat for wildlife, offer educational opportunities for students, and serve as living laboratories for scientists.  Video Transcript Estuaries: Where the River Meets the Sea.
Estuaries. 
Where freshwater rivers meet the salty open sea. There is a lot to love in an estuary. A popular destination for fishing, boating, birding and hiking, estuaries are a beautiful place to be. Miles of beaches, flowing grasses, marshes, creeks, and streams. This salty freshwater mix is where life begins and is the nursing grounds for 75% of the fish we catch.  Estuaries are lined with marshes and sea grasses that filter water flowing to the ocean and act as a buffer protecting us from coastal storms. 
NOAA works closely with coastal states to manage the National Estuarine Research Reserve System of 28 protected areas along the nation’s coasts. These valuable reserves are living laboratories for scientists and exciting, hands-on classrooms for students and teachers. At the reserves, scientists study sea level rise, water pollution, erosion, and impacts of human development. These studies provide strong scientific knowledge to help us create healthy, productive estuaries. The Chesapeake Bay, the ACE Basin in South Carolina, and San Francisco Bay in California, are just a few of the 28 reserves that can be found near you . So visit an estuary and experience firsthand the beauty and wildlife where the river meets the sea.
 **Did you know?** *Humans also rely on estuaries for food, recreation, jobs, and coastal protection. Of the 32 largest cities in the world, 22 are located on estuaries!*  More **Information** Estuaries: Nature's Water Filters (Animated Video and Quiz) National Estuarine Research Reserve System Estuaries (audio podcast) Estuaries, NOS Education   Get **Social** Social
  **Last updated:** 10/04/23 **Author:** NOAA How to cite this article Contact Us


Feedback Provide Feedback
							Contact Us
							Report an error
 Social Instagram Logo/a>


*Science. Service.Stewardship.*
 About NOS About Us
							NOS Program Offices
							Media Inquiries
							Website Acknowledgements
                            Site Index
							Disclaimer
 More Resources Freedom of Information Act
							Accessibility
							Information Quality
							Privacy Policy
							NOS For Employees
							USA.gov
 Department of Commerce
									National Oceanic and Atmospheric Administration (NOAA)
									National Ocean Service