Ocean Acidification Experiment


Who does ocean acidification affect?

Ocean Acidification is hazardous to all marine life, but it primarily affects those at the bottom of the food web, the organisms that support all life in the ocean. If these organisms were to disappear, their entire ecosystem would collapse.

As you have learned, the ocean is able to absorb a great deal of carbon dioxide from the atmosphere. However, carbon dioxide is being released in the atmosphere faster than the ocean can absorb it. It can no longer absorb as much CO2 as before, and that CO2 is causing massive changes in the ocean worldwide.  


To understand the affects of ocean acidification, we are going to be doing an experiment with clam and snail shells. Clams and snails are primary consumers, which means they are the second level of the food chain that eats producers like algae and seagrasses. Sometimes they even eat each other and other invertebrates. These organisms are vital food sources for animals higher up in the food chain and are greatly affected by ocean acidification because it makes it difficult for them to create shells. It also breaks down shells that are already formed, which is what you are going to see.

Go through the experiment below:


  • Empty shells from the beach (make sure these are empty and do not have living animals in them)
  • Water
  • Salt
  • Vinegar
  • 3 clear containers/glasses


1. Fill one container halfway with fresh water, one with salt water, and one with vinegar. There should be enough solution in the container to completely submerge the shell.


Before you begin the experiment, make some observations about the shells. Record their colour, shape, texture, and durability (are they hard or flexible). You may wish to take pictures of the shells to help remember your observations.

At the same time, place one shell in each of the glasses. Leave the shells undisturbed for one hour, then record observations from each of the containers.

Leave the shells in the containers overnight (approximately 12 hours) and record observations again from each of the samples.

Leave the shells again until 24 hours have passed since the start of the experiment. Take your observations again, this time removing the shells from their containers. What do you notice now about the shells in each of the containers?


  1. Are there any bubbles in the water?
  2. Has there been any change to the colour of the shell?
  3. Has there been any change to the shape of the shell?
  4. Has there been any change to the durability of the shell?


1. How did the shell change during the 24 hours in the freshwater? In the saltwater? In the vinegar?

2. How did the shell in the saltwater (basic) compare to the shell in the vinegar (acidic)?

3. Why do clams and crabs have shells? What purpose do the shells serve for their survival?

4. How would the acidic solution affect a clam living in the ocean? What does a weakened shell mean for the clam?

5. What are your sources of error? What would you need to change to eliminate this error?

6. Are your results valid? Why are why not? What would you have to do next to validate your results? 

7. Do you want to change any of your variables? How do you expect it to change your results?

8.  What are the implications of this experiment? How might your results impact the natural world? How might it affect humans  

9. Who benefits from the results of your study? Who might oppose your findings? 

10. Identify sources of carbon in your life. What changes can you make to your export of carbon that is reasonable? 

11. How can you communicate these findings to effectively encourage others to make a change to their carbon export?

Post about your results and observations in a blog!

To return to the Ocean Made Earth Habitable page, click HERE

To take the principle quiz, click THIS

Learning Objectives

To understand the affects of ocean acidification on the primary producers and primary consumers of the ecosystems, and why they are important to the health of the ocean.

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