Which ecosystem exists in the upper coastal intertidal zone between land and sea?

The upper coastal intertidal zone, where land meets the sea, is characterized by a unique ecosystem that is specifically adapted to the varying conditions of this environment. Salt marshes thrive in this region due to their ability to tolerate saline water and periodic flooding from tidal changes. They are dominated by salt-tolerant grasses and herbs, which can withstand both saltwater and changing moisture levels. This ecosystem plays a crucial role in coastal protection, habitat provision for various terrestrial and marine species, and carbon storage.

Coral reefs, while important coastal ecosystems, are predominantly found in warm, shallow marine waters and do not exist in the intertidal zone between land and sea. Swamps and wetlands present in coastal areas typically suggest environments associated with freshwater systems and are not specifically representative of the upper intertidal zone where salt marshes are. Thus, the characteristics and conditions of the upper coastal intertidal zone make salt marshes the correct classification for the ecosystem found there.