1. Carbon Cycle and Ocean Acidification Inspiration 9 V. Soutar

2. pH Scale Based on the dissociation of water into hydrogen ions and hydroxide ions Scaled from 1 to 14 A pH of 7 is known as “neutral”, meaning hydrogen (H) = hydroxide ions (OH) More hydrogen ions increase acidity Technical Definition: pH = -log([H + ])

3. 3 The pH Scale A single step from one number to another number on the pH scale is a large change or giant step. Most organisms are very sensitive to changes in pH. Their survival is usually within a relatively narrow pH range. So, how many times greater is pH 7 than 6? www.thegardenersresource.com ACIDS BASES

4. http://www.chem.ubc.ca/courseware/pH/section3/index.html Interpreting the Diagram

5. Diagram tells me: Strong acids release more H+ Strong bases release more OH- pH 7 has equal amount of H + and OH - pH scale goes from 1-14; pH 1-6 acid; 7 neutral; 8-14 base pH 1 strongest acid; pH 14 strongest base

6. What is the trend? H+ concentration increases pH decreases and the concentration of OH- decreases OH- concentration increases pH increases and H+ decreases Acids release more H+ and bases release more OH-

7. Connection to the Carbon Cycle and Ocean Acidification What is a biogeochemical cycle? What are the sources and sinks for carbon? How could excess carbon dioxide in the atmosphere and the oceans cause ocean acidification? What are some ideas for experiments to test the affect of ocean acidification on marine life?

8. http://www.google.com/imgres Why is this called a biogeochemical cycle?

9. http://www.physicalgeography.net/fundamentals/9r.html What are the sources and sinks in the carbon cycle?

10. atmospheric CO 2 275 300 325 350 375 400 19501960197019801990200020102020 8.03 8.08 8.13 8.18 8.23 8.28 8.33 8.38 pH Year CO 2 Mauna Loa oceanic CO 2 pH Feely et al. 2008 Increasing CO 2 and Ocean Acidification What data supports acidification theories?

11. What are the impacts of increased atmospheric carbon dioxide on the ocean? Carbon dioxide diffuses into the oceans increasing carbonic acid which reduces pH; makes ocean slightly less alkaline (slightly more acidic) Concentration of carbonate ions decreases so less structural material for shell building Less carbonate in solution for coral reef building

12. Carbon in Seawater CO 2 CO 2 + H 2 O H 2 CO 3 Carbonic Acid H + + HCO 3 - Bicarbonate H + + CO 3 2- Carbonate K1K1 K2K2 K0K0 K1=K1= [H + ][HCO 3 - ] [H 2 CO 3 ] Dr. Brian Hopkinson

13. Atmospheric CO 2 in seawater - Effective Reactions – Carbon buffering - Reduces pH, CO 3 2- - Increases CO 2, HCO 3 - CO 2 + H 2 O → H 2 CO 3 H 2 CO 3 + CO 3 2- → 2HCO 3 - Dr. Brian Hopkinson