Living in Intertidal Zones
The intertidal zone, or littoral zone, is a marine aquatic environment that is submerged at high tide and exposed at low tide. Organisms that live here must be able to adapt to different salinities, pounding waves, a range of temperatures, and exposure to air.
The intertidal zone can be divided into 4 sections:
So why would any animals live in the harsh, intertidal environment??
The intertidal zone can be divided into 4 sections:
- Spray zone, which is above high tide and typically only receives splashes from the waves; the few animals that can survive here include fungi and algae, isopods and periwinkles
- High Tide Zone, which gets covered during high tide. These animals must be able to survive long periods of exposure to the air. Animals include anemones, barnacles, brittle stars, chitons, crabs, green algae, isopods, limpets, mussels, sea stars, snails, whelks and some seaweed .
- Mid Tide Zone gets exposed by low tide but is covered by the high tide. Since this zone stays wetter longer. Organisms in this area include anemones, barnacles, chitons, crabs, green algae, isopods, limpets, mussels, sea lettuce, sea palms, sea stars, snails, sponges, and whelks. Rock pools that contain water can also provide a habitat for small fish, shrimps, krill, sea urchins and plankton.
- Low Tide Zone stays moist almost all of the time due to nooks and channels that contain water even during the lowest tides. Animals include anemones, seaweed, chitons, crabs, green algae, hydroids, isopods, limpets, mussels, nudibranchs, sea cucumber, sea lettuce, sea palms, sea stars, sea urchins, shrimp, snails, sponges, surf grass, tube worms, and whelks.
- The Sea Star has tube feet to hold tight onto rocks
- Limpets can clamp down
- Worms and Sea Palms are very flexible
- Mussels use attachment threads
- Barnacles can close their top (trap door) sealing in water for long periods of time.
- Snails will cluster, secrete a gluelike mucus to to stick to the rocks and withdraw into their shells to avoid dessication (drying out).
- Some fish can breathe air at the surface, this allows them to survive in oxygen poor tide pools
- Due to long exposure to predators, some animals have developed escape plans:
-Sea Cucumbers, when disturbed, may expel their entrails (internal organs), leaving those for the predator while the sea cucumber escapes. The organs will regenerate over several days.
So why would any animals live in the harsh, intertidal environment??
- Abundant sunlight allows algae and other plants to grow and support lots of animals
- Continual waves bring nutrients and oxygen
- Food is abundant
- Rocks provide surfaces to cling to and lots of hiding places