An estuary is a coastal area where fresh water from rivers and streams mixes with salt water from the ocean. Many bays, sounds, and lagoons along coasts are estuaries. Portions of rivers and streams connected to estuaries are also considered part of the estuary. The land area from which fresh water drains into the estuary is its watershed. Estuaries come in all shapes and sizes, each unique to their location and climate. Bays, sounds, marshes, swamps, inlets, and sloughs are all examples of estuaries.
An estuary is a fascinating place from the largest landscape features to the smallest microscopic organisms. When viewing an estuary from the air on is practically amazed by dramatic river bends as freshwater finds its way back to the sea. The vast expanse of marsh grasses or mudflats extend into calm waters that then follow the curve of an expansive barrier beach. Wherever there are estuaries, there is a unique beauty. As rivers meet the sea, both ocean and land contribute to an ecosystem of specialized plants and animals.
At high tide, seawater changes estuaries, submerging the plants and flooding creeks, marshes, panes, mudflats or mangroves, until what once was land is now water. Throughout the tides, the days and the years, an estuary is cradled between outreaching headlands and is buttressed on its vulnerable seaward side by fingers of sand or mud.
Estuaries transform with the tides, the incoming waters seemingly bringing back to life organisms that have sought shelter from their temporary exposure to the non-aquatic world. As the tides decline, organisms return to their protective postures, receding into sediments and adjusting to changing temperatures.
The community of life found on the land and in the water includes mammals, birds, fish, reptiles, shellfish, and plants all interacting within complex food webs. Flocks of shore birds stilt through the shallows, lunging long bills at their abundant prey of fish, worms, crabs or...