That depends on where the wetlands are located. If they are coastal wetlands, which are accessible to the sea, they will have a marine or estuarine enviroment. If they are further inland, where they are inaccessible to the sea, they will have a fresh water environment.
Both
freshwater
groundwater has more freshwater than rivers and lakes
saltwater freshwater saltwater freshwater
they are both saltwater and freshwater
They contain saltwater and freshwater
The Persian Gulf is saltwater, not freshwater.
Most lakes contain freshwater. From this fact, I'm assuming it is made out of freshwater, rather than saltwater.
Freshwater
freshwater
Freshwater.
the densities are different (Saltwater has a greater density than freshwater.)
A. L Kontis has written: 'Simulation of freshwater-saltwater interfaces in the Brooklyn-Queens aquifer system, Long Island, New York' -- subject(s): Saltwater encroachment, Groundwater flow
An estuary is the place where freshwater and saltwater meet.