Nov. 26 / Ocean Acidification

4 places where seawater gets ions

1. Atmospheric gases

2. Weathering and erosion

3. Volcanic activity

4. Biological processes

What’s the pH of pristine pure fresh water?

7 (neutral)

What’s the pH of seawater?

8.2 (basic)

What happens when we add CO2 to seawater?

It becomes more acidic

What trend has been observed in pH values since the 1850s?

Decrease

What has been happening to the amount of dissolved carbon dioxide in the oceans?

Increasing

What does ocean acidification have to do with coral reefs?

Coral skeletons are made of calcium carbonate, and acidification changes ocean chemistry and calcification. As more hydrogen ions are released, it combines with carbonate and steals it from the coral

What will happen to corals as ocean water becomes more acidic?

• Decreased growth rates and skeletal density

• Will use more energy which limits energy for reproduction

Will corals dissolve due to acidification?

No, because they have flesh over their calcium carbonate skeletons.

How does most of the CO2 produced from fossil fuels enter our oceans?

At the air-water interface, only from CO2 in the atmosphere.

How would you describe the relationship between seawater pH and atmospheric CO2?

As atmospheric CO2 increases, seawater pH decreases.

Which chemical compound is primarily responsible for forming the shells of marine calcifiers?

CaCO3 (calcium carbonate)