Part 1 of Essay
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 . Portions of rivers and streams connected to are also considered part of the estuary. The land area from which fresh water drains into the estuary is its watershed ....

Part 2 of Essay
.... 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 ....