Estuaries can be found in some habitat. A coast embayed with numerous estuaries is likely to be a shoreline of submergence.
Estuaries are simply known to be lined with marshes and sea grasses that filters water moving/flowing into the ocean. They are referred to as buffers that protect man from coastal storms.
They make the environment to be different from both the freshwater river and the sea. They are said to be formed where pre-existing valleys were flooded at the end of the last glaciation.
