Q: What is an estuary?
An estuary is a partially enclosed body of water along the coast where freshwater from rivers and streams meet and mix with salt water from the ocean. Estuaries and the lands surrounding them are places of transition from land to sea, and although influenced by the tides, they are protected from the full force of ocean waves, winds, and storms by such landforms as barrier islands or peninsulas.
Q: What Types of Animals Live in Estuaries?
Many types of animals are found in estuaries. In fact, the complex food web found in an estuary helps to support an amazing diversity of animals. The decaying plants are eaten by microorganisms (animals so tiny you need a microscope to see them.) The microorganisms are eaten by small invertebrates (animals without backbones.) Fish, like carp and stickleback, then eat the invertebrates. Many of the fish we eat depend upon estuaries. They are sheltered places where fish can have their young and the young fish can grow before moving out into the open ocean. Without estuaries, the number of fish in our oceans would decrease greatly. Occasionally, water in certain areas of the estuary can dry up and all that is left is a mud flat. It may seem like there is no life in this mud flat at all, but there are all kinds of mussels, shrimp, worms and other invertebrates living in the mud. Often you can see birds probing the mud with their beaks looking for a tasty meal.
Q: What Types of Plants Live in Estuaries?
- The estuary is a hostile environment for most plants because salt dominates. A few grow further back on the shore, where they live in a fluctuating environment of sea water and fresh water. These plants must cope with:
- varying salinity levels
- strong currents and storm waves
- varying exposure to sunlight and wind
- low oxygen levels in muddy soil
Examples of plants you will find in an estuary are smooth cord grass, sea grass, spiked grass, glassworts, sea lavender, marsh elder, sweet gale and seaside goldenrod.
Q: What Role do Estuaries Play in Earth’s Cycles?
- Estuaries are connected to many different cycles on Earth including the nutrient cycle, the water cycle and the cycle of life.
- In the nutrient cycle, estuaries serve as a place were many elements are recycled and made available to living organisms. These elements must be kept in balance to maintain the health of the estuary.
- In the water cycle, estuaries serve as places where evaporation of water occurs, and also serve to recharge ground water.
- In the cycle of life, estuaries provide shelter, food and nursery grounds for animals. Decomposing animals in estuaries can provide nutrients for other organisms.
Q: How are Estuaries Connected to My Life?
Estuaries are important parts of our lives; interconnected to our economy, hobbies and culture, and an important part of our coastal and ocean ecosystems.
- Estuaries provide commercial economic benefit to the U.S. in the form of seafood sales and jobs.
- Recreational activities – such as fishing, birding, boating and hiking – are enjoyed by millions of Americans each year in estuaries bringing income to coastal communities.
- Estuaries offer cultural importance to Americans. They are often city and trade centers, they are an important source of food, the buffer communities from storm surges, and they have a long history of cultural use by Native Americans.
- Estuaries are vital ecosystems providing diverse habitat and nursery areas for many important organisms.
Because we are all connected to the nation’s coasts, our activities have many effects on estuaries, many of which are negative.
- Anthropogenic disturbances to estuaries include coastal development, introduction of invasive species, pollution via runoff, over fishing, dredging and filling, dams and global climate change.
- From government agencies and laws – established to protect estuaries – to volunteer citizens groups, our coasts are protected, restored and conserved in many ways.
- There are many things you can do around your home and in your community to keep estuaries clean.
Q: Why are estuaries important?
- Estuaries serve as sponges. As water flows from the land to the ocean, the water is filtered by the vegetation, and silt is trapped. Estuaries can also filter small amounts of pollution out of the water before it reaches the ocean.
- Estuaries serve as important natural buffers, protecting upland areas from erosion and natural storm surge.
- Estuaries provide a safe haven and protective nursery for small fish, shellfish, migrating birds, and coastal shore animals. In the U.S., estuaries are nurseries to over 75% of all fish and shellfish harvested.
Estuary Data Mapper (EDM) Frequently Asked Questions (FAQ). https://coast.noaa.gov/digitalcoast/tools/edm.html
Estuary Education, National Estuarine Research Reserve System. https://www.epa.gov/hesc/estuary-data-mapper-edm-frequently-asked-questions-faq
Chesapeake Bay Program. Bay FAQ. http://www.chesapeakebay.net/faq/keywords/estuary#inline
Estuary Biomes. Estuary Animals. http://excitingfacts.weebly.com/estuary-animals.html
NH Department of Environmental Services Coastal Program. “Life in New Hampshire Salt Marshes – A Quick-Reference Field Guide. February 2005. https://www.des.nh.gov/organization/commissioner/pip/publications/wd/documents/wd-04-19.pdf