Acidity and Climate Change in the Arctic

Purpose

To apply prior knowledge of chemistry to the acidification of our oceans. This can be a computer lab or library based activity

Procedure

1. Set up a glass tank in your classroom and grow a population of algae in water. Local pet supply stores will most likely give you some for free from their fish tanks!
2. Set up a chart and record the pH of the water for several days. It should be fairly stable.
3. Add a couple of drops of vinegar every 3 or 4 days.
4. Record the pH in the chart
5. Note any changes in the size of the algae population

Discussion

Available in PDF attached.

Extensions

1. What are methane hydrates and how are they involved in the ocean’s "carbon sink"?
   Methane hydrates are sources of "frozen methane". It can float on water or even sink. They are found deep in the ocean floors and in permafrost. If they melt, the methane is released, which would contribute a major source of a greenhouse gas. Methane is a significant greenhouse gas and degrades into carbon dioxide.

2. What are possible "drivers" that may cause the ocean to act as a “carbon sink”?
   "Carbon sinks" include anything that absorbs carbon dioxide – including oceans, as well as green trees. Anything that encourages the absorption of carbon dioxide would be considered "drivers", encouraging the uptake of carbon dioxide. A "driver" for the absorption of carbon dioxide into the ocean might include increased plant life or increased atmospheric carbon dioxide. Oceans are estimated to have absorbed almost half of human CO2 emissions. Increased acidity of the ocean endangers marine plant and animal life.

3. How might the ocean act as a carbon "source"? If the organic material decomposes or rots, carbon dioxide is released into the water. This process requires oxygen.

Credits

Janet Nadeau (nadeau.janet [at] gmail.com)