1. What is ocean acidification?
Developed by Brian Erickson ©2017

2. Shellfish A general term, often describing food
Animals with a shell/exoskeleton
Live in water
Includes:
Oysters, mussels, clams, slugs (Mollusks)
Shrimp, lobsters, crabs (Crustaceans)
Urchins, sea stars, sand dollars (Echinoderms)
You were looking at a few examples of shellfish. This is a general term often used to describe food.
Picture from By Gary Houston (Own work) [CC0], via Wikimedia Commons,

3. “seed”
There will be a lot of talk about “seed” in the upcoming video. All they mean is the young oyster, typically within the first 2 weeks of life. At this point they are free swimming. Spat are the juveniles once they are ready to settle down and attach, usually to another shell or hard surface.
Image from Chesapeake Quarterly, Maryland Sea Grant, accessed

4. Cal Poly Pier in San Luis Bay

5. The Case of the Dying Oysters
As you watch, consider the questions in your handout.
Give students 10 minutes to read and answer questions, then discuss for 5 minutes (~15 minutes total)
After student brainstorm, mention they just did what scientists and engineers do all the time: identify a problem, come up with possible causes and ways to test their ideas. The hatchery managers and scientists did they same thing… (next slide)

7. Human activities release CO2.
The ocean absorbs ~25% of anthropogenic CO2.
Ocean chemistry changes.
Remind students to fill in their notes with the steps presented
CO2(g)
+ H2O(l)
↔ H2CO3(aq)
H2CO3(aq) ↔ H+(aq) + HCO3-(aq)

8. CaCO3(s) ↔ Ca+2(aq) + CO3-2(aq)
An example:
Carbonate, used for shell building, becomes less available. It takes more energy to make shells, leading to fewer & smaller shellfish.
Shellfish filter water. Fewer shellfish could lead to cloudier water. Cloudy water makes it harder for seagrasses to do photosynthesis. Seagrass beds are important habitat for young fish.
Less seagrass could mean fewer fish to catch.
This could impact humans who rely on fish for food & jobs.
CaCO3(s) ↔ Ca+2(aq) + CO3-2(aq)
Mention that we aren’t only talking about fishermen and fish eaters. This also could impact restaurants, people who work at packing plants, ice plants, truck drivers, dock workers, government scientists…
Oyster filtering image:

9. Ocean acidification:
the change in ocean chemistry due to increasing amounts of anthropogenic carbon dioxide (CO2) in the atmosphere
(Mention to students that the yellow, underlined words match the blanks in their notes)
Ocean acidification is often defined as a change in pH, but this misses some of the key points. We are calling it a “change in ocean chemistry,” and over the next few days we’ll find out what this means and why it is important to have a broader definition.
Photo by Lance Asper-
Anthropogenic: human created; coming from humans or their activities