Marine Ecology 101

Welcome to part two of our three part blog series (see part onethree, four and five) on the best ways to enjoy San Diego’s very own ASBS and Matlahuayl State Marine Reserve. La Jolla Cove and La Jolla Shores are both protected areas — the Cove and Shores are both classified as Areas of Special Biological Significance and La Jolla Shores is also a marine reserve known as the Matlahuayl State Marine Reserve. These posts will show you how to enjoy these special places while not harming those that live there. 

Before we go exploring the tidepools, let’s learn a little bit more about this habitat.


Many species live in the narrow band between the sea and the land. Some of them make rocks their home because of the support it provides for them. These creatures are subject to many hardships: they have evolved to endure desiccation, wave impact, and insane temperature changes. Because of this they often have hard bodies with shells or calcareous (a hard, cement-like substance) deposits. Tidepools are filled with competition. Space is scarce on the rocky shore and the organisms are constantly fighting for it. They try to outgrow each other and often get creative to find new spaces. They also have to protect themselves from wave impact which is why they are often strongly attached to rocks.

The lower parts of the rocky shore are occupied by algae and other organisms that are willing to stay underwater most of the time. The higher parts are full of limpets (#8 on illustration) and barnacles (#3 on illustration) that are able to survive long periods with out water, also known as desiccation. The level of exposure to the waves and other environmental factors results in zonation of the tidepools.

Stronger organisms live in parts of the tidepools exposed to stronger waves (High Tide Zone) while fragile ones hide in protected areas (Low Tide Zone).

The zonation is very important to keep the balance of this amazing coastal ecosystem. The food web (who eats who) in the tide pools is quite complex — it consists of many levels and many different predators. As a consequence, each species has adapted to a different strategy to obtain food, creating rich and beautiful biodiversity.

tide-pool-tramplingFragile Beauty

All this ocean beauty could be menaced by our activities.

Walking (trampling)
The constant stepping on top of rocks removes their algal cover and destroys the tide pool community.

Collecting animals or even empty shells can leave the hermit crabs homeless.

Urban runoff
After it rains, the sediments and pollutants from the streets can be deadly to the tidepool creatures.

Our trash can enter the tidepools and cause damage. We need to take action to protect the tidepool communities.

The tidepools house many living creatures — when we explore them we are only guests. In the next posts, we will see what it takes to be good guests. We will talk  about “house rules”, and the ways to take care of ourselves while in this beautiful wild place.

Written by Thais Fonseca Rech