Importance of Estuaries

An estuary (pronounced ) is a coastal area where fresh water from rivers and streams mixes with salt water from the ocean. Many bayous and lagoons along coasts are estuaries.

The community of life found in these waters and associated wetlands include mammals, birds, fish, reptiles, shellfish, and plants - all interacting within complex food webs.

Estuaries have economic, recreational, and aesthetic value. People are attracted to the water and visit estuaries to boat, fish, swim and enjoy their beauty. As a result, the economies of many coastal communities depend on the natural beauty and bounty of their estuaries. In fact, almost 70 percent of the economy in the Coastal Bend can be directly or indirectly attributed to our bays and estuaries in some way.

Estuaries come in all shapes and sizes, each unique to their location and climate. Where there are estuaries, there is unique beauty. When viewing an estuary from the air the dramatic river bends, marsh grasses, and mudflats paint a unique mosaic scenery.

With all the physical forces at work in an estuary (the flow of rivers; the deposition of sediments; the ebb and flow of tides) conditions are constantly changing. Species that evolve in estuaries are therefore adapted to tremendous variability and extreme conditions in their environment.

Long considered to be wastelands, estuaries have had their sediments dredged, marshes and tidal flats filled, water polluted, and shorelines reconstructed to accommodate housing, transportation, commerce, industry, and agricultural needs.

As our population grows and the demands imposed on our natural resources increase, so too does the importance of protecting these resources for their natural and aesthetic values.

Why Estuaries Matter
Nurseries: Many marine organisms, and most commercially valuable fish species, depend on estuaries at some point during their development.

Productivity: Within the sediments -- whether mud, silt, sand or rocks --live billions of microscopic bacteria, a lower level of the food web that subsist largely on decaying plants. Nutrients are essential to a healthy aquatic ecosystem, but in excess can lead to algal blooms causing eutrophication, a condition which results in low dissolved oxygen.

Water Filtration: Water draining from uplands carries a load of sediments and nutrients. As the water flows through salt marsh peat and the dense mesh of marsh grass blades, much of the sediment and nutrient load is filtered out. This filtration process creates cleaner and clearer water.

Flood Control: Porous, resilient salt marsh soils and grass absorb flood waters and dissipate storm surges. Salt marsh dominated estuaries provide natural buffers between the land and the ocean. They protect upland organisms as well as billions of dollars of real estate that might otherwise be subjected to more intense natural forces.

The CBBEP has provided a Powerpoint presentation on the estuaries in the Texas Coastal Bend for you to use in the classroom. Please click here to download.

The CBBEP has been working on another important project which is considered to be the "heart of the estuary" - the Nueces Delta Preserve. To find out more, please download the project description and map by clicking on the following links.