A Time for Tides
Science

A coastal area covered by the highest of the high tides, mostly exposed to air
High-intertidal zone
A coastal area covered by the highest of the high tides, mostly exposed to air. high-intertidal zone. The high-intertidal zone is the part of the shore that gets covered by the sea only during the highest tides.

A coastal area exposed to air at the lowest of low tides and is primarily marine in character
Low-intertidal zone
A coastal area exposed to air at the lowest of low tides and is primarily marine in character. Low-intertidal zone. This zone is where the ocean meets the land and is mostly underwater, but it's exposed to air during the very lowest tides.