5/15 PitU: This week: Climate and physics

Acid and the ocean

The average pH of the ocean is 8.1, which means it is on the base side of the pH scale (remember, less than 7 is acidic, greater than 7 is basic). When scientists talk about ocean acidification, they are actually talking about ocean ‘de-basicifiction’—but that doesn’t sound as good 🙂

Ocean acidification

An unusual type of acid is carbon dioxide (CO₂). It’s unusual because most acids have a hydrogen atom/ion on them somewhere that can dissociate when the acid is mixed with water. Here’s the process that carbon dioxide undergoes when mixed with water:

How carbonic acid effects shells in the ocean

Watch the following video. It is part a review of acid/bases and pH, and part an introduction to oceans turning a bit more acidic.

Reading & questions

Read the article here.

Questions

1. What is pH and how is it measured?
2. How is ocean acidification related to a global increase in temperature?
3. What is the Kyoto Protocol? 
4. What chemical reaction happens when CO₂ and seawater (H₂O) mix?
5. Explain how shelled organisms are negatively impacted by ocean acidification.
6. What are a few ways you can help reduce global ocean acidification?

Submit photo of answers

Submit a photo of your answers here. If you use more than one page, it’s OK to only submit the first page.

Further reading/viewing

If you’d like more information on this topic, here are some resources:

• NOAA Education
• Oyster farmers and ocean acidification (4 min video)
• ACID TEST: The Global Challenge of Ocean Acidification (22 min video)