Answer:
Rocky intertidal zones hosts variety of organisms such as algae, seaweed, snails, crabs, etc. However, scientists have divided the zones into further three zones namely high tide, middle tide, and low tide. These divisions are mainly based on oxygen level. For example, those organisms that cannot surive high oxygen concentration are often found in the low tide zone. This is the reason that low tide zone hosts maximum biodiversity and thus also used as a health proxy for a coastal ecosystem. A decline in biodiversity in low tide zone is a serious concern of marine ecosystem.
