What are the examples of ecosystems? stream) A. Estuaries (the tidal mouth of a large river, where the tide meets the B. Intertidal zones (the intertidal zone is the zone between the high tide and low tide, also referred to as the foreshore, seashore, or littoral zone. It is, hence, an environment where seawater and air are interchanged repeatedly from the constant breaking and receding of waves.) ​