Added carbon dioxide shifts reactions involving dissolved carbon dioxide, bicarbonate, carbonate and hydrogen ions. More hydrogen ions can reduce carbonate availability. Organisms respond in different ways, and local conditions also matter. The activity illustrates a chemical mechanism without equating every pH change with immediate shell loss or organism death.
Water and oceans · Discover & try
Can seawater acidify while it is still basic?
Reading level 4 of 5 · FluentChange
Word help
pH
A logarithmic measure related to hydrogen-ion activity.
Acidification
A decrease in pH, even if the solution remains basic.
Carbonate
A dissolved ion used in calcium-carbonate shells and skeletons.
Watch · Try · Explain
See how it works
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Selected pH states and exact logarithmic ratios; no local carbonate-system or biological forecast.
What to look for
- Read lower pH as more hydrogen ions.
- Check that every selected pH is still above seven.
- Separate the exact ratio from qualitative carbonate changes.
Explain what you noticed
A separate seawater sample changes from pH 8.3 to pH 8.0. Has it acidified?
Keep this idea: Acidification means a decrease in pH; seawater can become less basic without crossing pH 7.
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Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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