Ocean Acidification Lab
Raise atmospheric CO₂ and watch ocean pH fall and carbonate ions disappear, using the real carbonic acid chemistry behind ocean acidification.
How to use: raise atmospheric CO₂ and watch it dissolve into the ocean, drop the pH, and lower the carbonate saturation state that shells and coral skeletons depend on.
Challenge 1: find the undersaturation point
Raise CO₂ until the aragonite saturation state Ω drops below 1 - the point where shells and coral skeletons start dissolving rather than growing.
Challenge 2: keep pH drop under control
Set the CO₂ growth rate so that after running 50 years, the pH has dropped by less than 0.1 units from its starting value.
About the Ocean Acidification Lab
Free ocean acidification lab. Raise atmospheric CO₂ and watch ocean pH fall and carbonate ions disappear, using the real carbonic acid chemistry behind ocean acidification. Drag, change the sliders and see the result live. No sign-up, works on phone and computer. Built for environmental science, the ocean acidification lab runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
Raise atmospheric CO₂ and watch ocean pH fall and carbonate ions disappear, using the real carbonic acid chemistry behind ocean acidification. Use it to explore environmental science ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the Ocean Acidification Lab
- Use the controls to change Atmospheric CO₂ (ppm), CO₂ growth rate (ppm/yr). The simulation reacts instantly.
- Press "▶ Run years", "Reset run", "⏭ Fast-forward to 2100 (business-as-usual)", "Reset to defaults" to start, reset or change what is happening.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Run the model at today's real growth rate and watch pH and Ω both fall over decades.
- Push CO₂ to 900+ ppm and find where Ω crosses below 1.
- Compare the pH drop after 50 years at a low versus a high CO₂ growth rate.
- Reset to pre-industrial 280 ppm and see Ω near its healthiest value.
Key ideas you can learn
- Dissolved CO₂ reacts with seawater to form carbonic acid, which releases hydrogen ions and lowers pH: CO2 + H2O ↔ H2CO3 ↔ H⁺ + HCO3⁻.
- Those extra hydrogen ions react with existing carbonate ions to form more bicarbonate, so rising CO₂ directly consumes the carbonate ions that shell- and coral-building organisms need.
- Aragonite saturation state Ω measures whether seawater favors shell growth (Ω ≥ 1) or shell dissolution (Ω < 1); it falls as carbonate ion concentration falls.
- Ocean acidification and the atmospheric greenhouse effect share the same root cause - rising CO₂ - but they are two separate, simultaneous problems: one changes ocean chemistry directly, the other traps heat.
Where this is used in the real world
Marine biologists and shellfish farmers track exactly this aragonite saturation state, since oyster and coral reef hatcheries have already reported real production losses tied to falling Ω in coastal waters.
Who is this simulation for?
Students, teachers and curious learners of all ages.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
Why does dissolving more CO₂ in the ocean lower the carbonate ion concentration rather than raising it?
The added carbonic acid's hydrogen ions react with existing carbonate ions (CO3²⁻) to form bicarbonate (HCO3⁻), converting one form of dissolved carbon into another and net removing free carbonate ions from the water even though total dissolved carbon goes up.
Why does the ocean's role in acidification often get less attention than its role in the greenhouse effect?
The ocean absorbing CO₂ actually helps slow atmospheric warming by removing a greenhouse gas from the air, but that same absorbed CO₂ directly acidifies the seawater and lowers carbonate availability - so the very process that buys time against climate change is quietly damaging marine chemistry.
Is the Ocean Acidification Lab free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the Ocean Acidification Lab work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.