The Rocky Intertidal Zone: Nature’s Krabby Patty

As we embrace the “SpongeBob SquarePants” theme that our blog site has recently been blessed with, I invite you on an exciting journey to get a taste of Nature’s Krabby Patty: the rocky intertidal zone at Aguilar Point on Vancouver Island’s Pacific coastline. Although it may lack the familiar ingredients (a frozen hamburger, fresh lettuce, crisp onions, tomatoes, sea cheese, pickles, mustard, ketchup, and a secret formula), all of the excitement is preserved in Nature’s Krabby Patty, as it layered with some of the highest diversity found in any ecosystem around the world!


Pedal disk of the anemone Conostichus ornatus. Image from stichus.htm

We begin our journey at the burger’s bottom bun closest to the ocean: the low tide zone, containing the most life of all zones within the rocky intertidal ecosystem. This zone is not often exposed to air, so organisms here must be well suited to withstand the intense forces of waves, and are generally not well adapted to air exposure. For example, in our survey of this zone, we found large invertebrates such as the giant green anemone, which maintain a firm grip onto the rocks with a pedal disk, and extend stinging tentacles into the water to capture and immobilize passing prey.


Blue mussels anchored to rocks with byssal threads. Image from

Next, as we ascend into the Patty’s filling, we enter the mid tide zone. Here, organisms must still be well adapted to withstand wave forces, but must also be able to survive more prolonged air exposure. For that reason, in this zone we found mussel beds providing habitat for many other invertebrate species. As the tide recedes, the mussels are able to seal their shells tightly to prevent becoming dried out. Additionally, they secure themselves firmly to the rocks (and to each other) using byssal threads, to prevent being displaced by the waves.


A chiton sealed to a rock. Image from http://www.democraticunder

Finally we reach the top bun, and find the high tide zone. Life here spends a majority of its time exposed to air, and therefore must be very well adapted to prolonged dry periods. As such, in the high tide zone we found black turban snails, chitons, and limpets resisting drying out with their shells sealed completely to rocks.

As we conclude our journey together, we have discovered a just a taste of the diversity of strategies that organisms use to survive the harsh conditions of the rocky intertidal zone. If you have the opportunity, indulge yourself and take a trip to a local shoreline, where if you look closely you will be able to explore countless other strategies organisms use to survive in different intertidal ecosystems. To further wet your appetite, visit the CRD website to learn more about intertidal zones and their inhabitants, why intertidal zones are important, and what you can do to protect them! (






Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s