estuary
You will see the term defined various ways, including "a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea" and "the part of the wide lower course of a river where its current is met by the tides". But, this is almost certainly the term you are looking for. An estuary environment is where salt and fresh water are mixed.
fresh or salt water surrounded by land
Yes: Intertidal zone
estuary
Estuary
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estuary
an estuarie
Antarctica is surrounded by a salt-water sea: the Southern Ocean.
Since they're surrounded by water/coastal areas, they made polders and dikes.
Both salt and fresh water flow into one. The definition is: A semi-enclosed coastal body of water, which has a free connection with the open sea. So it would be salt water.
brackish water
A body of water such as you describe would be the ocean itself.
A body of fresh water surrounded by land is a lake or pond.
a fresh water pond
a gulf!
Estuary
Australia people drink fresh water like we do, though their continent is surrounded by ocean water.
Lake
A lake.
estuary
Yes. There are amoebae in bodies of fresh water in the coastal regions of Texas.
a fresh water pond