1. The Dangers of Ocean Acidification Scientific American March 2006, pp 58-65 Scott C. Doney

2. Question 1 Is the rate of CO 2 appearing in the atm (R in ) equal to the rate of CO 2 being removed from the atm (R out ) by plant uptake and deposition in the ocean? The assumption in 1950 was that R in = R out. Scientists set up CO 2 monitors in Antarctica and Mauna Loa n 1958. Result: R in > R out. Fig 16.8, 16.9 in text.

3. Question 2 How much of the CO 2 from fossil fuel burning has been deposited in the oceans? 1980-1990 studies mapped carbon concentrations worldwide. 2004 analysis of these data determined how much of total carbon is from fossil fuel burning. Result: 50% of fossil fuel carbon has been deposited in oceans.

4. CO 2 Chemistry Pristine oceans have pH = 8-8.3 CO 2 + H 2 O  H 2 CO 3 carbonic acid (weak acid) H 2 CO 3  H + + HCO 3 - HCO 3 -  H + + CO 3 2- 2000, pH of oceans was 0.1 pH units lower By 2100, it may be 0.3 pH units lower

5. More Chemistry Shellfish, coral, phytoplankton need calcium carbonate for body building. There is competition for the carbonate ion (CO 3 2- ) between Ca 2+ and H + –Ca 2+ + CO 3 2-  CaCO 3 –H + + CO 3 2-  HCO 3 - As H + increases, the second rxn dominates, thus removing too much CO 3 2-.

6. Question 3 What is the effect of CO 2 in the oceans? Some phytoplankton that live at the water's surface are covered with CaCO 3 plates. –If the ocean's pH decreases, less carbonate ion will be available for plate building. –These plankton are a major food source for fish and marine mammals. –They are also important in converting sunlight to carbon containing molecules and oxygen.

7. Question 3 Coral are actually algae or sea anemone- related species that filter plankton and secrete CaCO 3 for structure. With reduced levels of the carbonate ion, less CaCO 3 is available and less coral is produced. Deep sea coral reefs are important habitats for fish. In turn, fish are eaten by marine creatures higher on the food chain.

8. Question 3 The colors characteristic of shallow water coral are due to bacteria. Environmental stress such at high T and low pH cause these bacteria to leave the coral surface causing coral bleaching.

9. Current Research Three Approaches Study the impact of increased CO 2 levels on a single species. Study an isolated portion of a real ocean habitat. Study geologic records to determine the impact of increased CO 2 levels in the ocean http://www.royalsoc.ac.uk/displaypagedoc.a sp?id=13314http://www.royalsoc.ac.uk/displaypagedoc.a sp?id=13314