Types of estuaries

There are several diferent types of estuaries.
An estuary is a body of water that has fresh water entering and is also open to the ocean. An estuary is a semi-enclosed, coastal body of water, that is connected to the open sea, with fresh water draining into it.
If you look at the state of Georgia you can see the Savannah river run through it. The Savannah river dumps into the Atlantic ocean and creates an estuary. Here is what a small portion of this estuary looks like.

Estuaries are known for their brackish water which is a combination of salt and fresh water. Estuaries have been called the "Nurseries of the Sea." because of the many phytoplankton that is found there help the food chain and provide food for many organisms.