Ocean Acidification - AP Environmental Science

1. What is the chemical formula for a carbonate ion?

   $\text{CO}_3^{2-}$. Carbonate ions are essential for marine organism calcification.

2. What is the role of the ocean in the global carbon cycle?

   Major carbon sink, absorbing CO₂. Oceans absorb about 25% of human CO₂ emissions.

3. What chemical reaction occurs when CO₂ is absorbed by seawater?

   $\text{CO}_2 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{CO}_3$. CO₂ dissolves in water to form carbonic acid.

4. What is the relationship between CO₂ and pH in oceans?

   Higher CO₂ leads to lower pH. Inverse relationship: more CO₂ absorption decreases ocean pH.

5. What is the formula for the bicarbonate ion?

   $\text{HCO}_3^-$. Bicarbonate ion is a major component of ocean chemistry.

6. Which process increases ocean water's CO₂ absorption capacity?

   Cold water circulation and mixing. Cold water dissolves more CO₂ than warm water.

7. Identify a method to monitor ocean acidification.

   Measuring pH and carbonate ion concentrations. These measurements track ocean acidification progress.

8. What is the typical pH of acidified ocean water?

   Less than 8.1. Acidified water has lower pH than normal ocean conditions.

9. Which gas is primarily responsible for ocean acidification?

   Carbon dioxide (CO₂). CO₂ absorption forms acids that lower ocean pH.

10. What is the pH range of normal ocean water?

    Approximately 8.1 to 8.3. Ocean water is naturally basic, well above neutral pH 7.

11. What is one ecological impact of ocean acidification?

    Disruption of marine food webs. Loss of calcifying organisms disrupts marine ecosystems.

12. How does ocean acidification affect coral reefs?

    Weakens coral skeletons, hindering growth. Lower pH reduces carbonate for coral skeleton formation.

13. Which chemical reaction removes carbonate ions from seawater?

    $\text{Ca}^{2+} + \text{CO}_3^{2-} \rightarrow \text{CaCO}_3$. Calcium and carbonate combine to form shells and skeletons.

14. Which option is a direct effect of increased ocean acidity?

    Coral bleaching. Acidification directly weakens coral structures, causing bleaching.

15. What chemical reaction occurs when $CO_2$ is absorbed by seawater?

    $\text{CO}_2 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{CO}_3$. $CO_2$ dissolves in water to form carbonic acid.

16. Which component of seawater buffers pH changes?

    Bicarbonate ions ($\text{HCO}_3^-$). Bicarbonate ions help maintain stable ocean pH levels.

17. What is the role of phytoplankton in carbon cycles?

    Absorb CO₂ during photosynthesis. Phytoplankton remove CO₂ from water during growth.

18. Identify a potential solution to mitigate ocean acidification.

    Reducing CO₂ emissions globally. Reducing the source of excess CO₂ prevents further acidification.

19. What effect does ocean acidification have on marine biodiversity?

    Potential decline in species diversity. Acidification harms calcifying species, disrupting ecosystems.

20. Which feedback loop exacerbates ocean acidification?

    Warmer oceans release more CO₂, lowering pH. Warming reduces CO₂ solubility, creating positive feedback.

21. What is the chemical formula for carbonic acid?

    $\text{H}_2\text{CO}_3$. Carbonic acid forms when CO₂ dissolves in seawater.

22. How does temperature affect CO₂ solubility in ocean water?

    Higher temperature decreases CO₂ solubility. Warmer water holds less dissolved CO₂ than cold water.

23. Identify a mineral affected by ocean acidification.

    Calcium carbonate ($\text{CaCO}_3$). Calcium carbonate dissolves more easily in acidic water.

24. State the impact of reduced carbonate ions on calcifying organisms.

    Weaker shells and skeletons. Less carbonate means calcifying organisms struggle to build structures.

25. Identify the primary cause of ocean acidification.

    Increased atmospheric CO₂ from human activities. Burning fossil fuels releases CO₂ that dissolves in oceans.

26. What is the effect of increased $\text{H}^+$ ions on ocean pH?

    Lowers pH, making water more acidic. More hydrogen ions decrease pH on the logarithmic scale.

27. Identify an economic impact of ocean acidification.

    Threat to fisheries and aquaculture industries. Declining marine ecosystems reduce seafood availability and income.

28. What is ocean acidification?

    Decrease in pH of ocean water due to absorption of CO₂. Ocean water becomes less basic as it absorbs atmospheric CO₂.

29. Identify a consequence of ocean acidification on human communities.

    Impacts on food security and livelihoods. Declining fisheries affect coastal communities economically.

30. Which oceanic organisms are most affected by acidification?

    Coral reefs, mollusks, and some plankton. These organisms build calcium carbonate shells and skeletons.

31. What is the effect of ocean acidification on pH levels?

    Decreases ocean pH levels. More hydrogen ions make ocean water more acidic.

32. Which human activities contribute most to ocean acidification?

    Fossil fuel burning and deforestation. These activities release the most atmospheric CO₂.

33. What is the chemical formula for a hydrogen ion?

    $\text{H}^+$. Hydrogen ions determine acidity levels in solutions.

34. How does ocean acidification influence fish behavior?

    Alters sensory perception and behavior. Higher acidity disrupts fish nervous system function.

35. What is a potential impact of ocean acidification on tourism?

    Damage to coral reefs affects recreational activities. Coral reef degradation reduces diving and snorkeling tourism.

36. State one indicator of ocean acidification.

    Decreasing pH levels in ocean waters. pH decline is the primary measure of ocean acidification.

37. How does ocean acidification affect marine life?

    It reduces availability of carbonate ions for shell formation. Lower pH decreases carbonate availability for shell-building organisms.

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