Adaptations of plants living in estuaries include the ability to survive in water of varying salinity levels, cells that store oxygen for use underwater, and the ability to reproduce by releasing new plants ready to germinate. These adaptations are in response to the variable conditions of estuaries.
An estuary is an area where fresh water and salt water mix. River deltas, bays and coastal swamps are all places where estuaries occur.
Mangroves, seagrass, sedges, saltworts and eelgrass are all plants adapted to estuary life. All of these plants are salt-tolerant and able to survive in brackish water. Brackish water is a mixture of fresh and salt water; its salinity level is between that of the river water and sea water that mix in the estuary.
Estuary plants are the most efficient plants in the world. They produce more energy from sunlight than forests, grasslands and farms. This is due to the higher nutrient content that sea water provides for estuary soil.
Animals also adapt to life in the variable conditions of estuaries. Oysters, coral, shrimp, fish and birds all make their homes in estuaries. Marine animals such as turtles and rays live in the saltiest, most open parts of estuaries.