High Tide Zone

• The high tide zone is flooded during high tide. Since the area drains quickly, the high tide zone tends to be very saline. Algae, barnacles, snails and hermit crabs exist in this zone.
  
  

Middle Tide Zone

• The middle tide zone is dry and wet for equal times during the day. It has a slightly higher salinity than the low tide zone. This area experiences more waves than the high tide zone. Sponges, crabs and seaweed live here. Life tends to be more diverse in the middle tide zone.
  
  

Low Tide Zone

• The low tide zone is submerged for most of the day. It is only dry during extreme low tide. Biodiversity is greatest in the low tide zone. Plant life, tubeworms, shrimp, sea cucumbers and urchins can be found in the low tide zone.
  
  

Coastal Marshes

• Coastal marshes form in areas that are free from waves. Coastal marshes may be inundated during high tide but are exposed to air during low tide. Clams, oysters and mussels can be found in coastal marshes.
  
  

Tidal Salt Marsh

• A tidal salt marsh is the most productive ecosystem in the coastal tidal zone. Tides wash in nutrients and wash out waste. Algae are very active in a tidal salt marsh, fixing nitrogen to provide nutrients to organisms living there. Organism population grows rapidly.
  
  

Rocky Coasts

• Organisms such as barnacles, mussels and sea urchins attach to rocks. Water that comes in during high tide can get trapped in certain areas of the rocky coast, forming tide pools.