1. Aaron Cevallos Advisor: Andreas Andersson, Ph.D. Summer 2010

2. What is ocean acidification? What is causing it? The ocean absorbs approximately 1/3rd of the CO2 emitted to the atmosphere from the burning of fossil fuels. As CO2 dissolves in seawater, the pH of the water decreases. Since the beginning of the industrial revolution, ocean pH has dropped globally by approximately 0.1 pH units. By the end of this century, we may expect to see changes in pH that are the greatest in 21 million years. http://ioc3.unesco.org/oanet/FAQacidity.html

3. Evidence of ocean acidification at BATS N. Bates

4. Bermuda coral reef: the canary in a coal mine? Buddemeier et al. 2004, based on Veron 1995 Alex Venn -Marginal reef -Lower [CO 3 2- ] -Healthy reef -No major industries or pollution -Natural gradient in [CO 3 2- ] [CO 3 2- ] across coral reef platform Outer rim Mid-platformInshore

5. What can we expect in the future ? http://ioc3.unesco.org/oanet/FAQacidity.html The IPCC expects: a drop in ocean pH of about 0.4 pH units by the end of this century a 60% decrease in the concentration of calcium carbonate Changes in atmospheric CO2 under the "business as usual" scenario to the year 2100 and associated changes in ocean pH and carbon chemistry. Adapted from Wolf-gladrow et al., 1999

6. Why is ocean acidification a problem? Seawater acid-base balance important in regulating biological and chemical processes, e.g.: Function of enzyme and proteins Chemical reaction rates Availability of nutrients and trace metals CO 3 2- is an essential building block for marine calcifiers depositing skeletons or shells made of CaCO 3 † Less building material equals slower growth, weaker structures (similar to osteoporosis in humans) and increased vulnerability to environmental stress in general † Ca 2+ is the other building block, but there are plenty of calcium in seawater

7. Ca 2+ CO 3 2- CaCO 3 The Alkalinity Anomaly Method The alkalinity anomaly method relies on the principle that when a calcifying organism produces a mole of calcium carbonate, total alkalinity is decreased by two moles. I will be able to know the exact degree to which synthesis or dissolution is taking place using this method.

8. Average Daytime vs. Nighttime Calcification Rates

9. The Buoyant Weighing Method http://www.aagaines.com/man/graphics/scale.jpg Calcification (or dissolution) of a coral sample is inferred from changes in the sample’s mass. The weight can be determined in water using the formula: W a = W w / [1- (p w /p s )]

11. AA Predicted Weight Change vs. BW Actual Weight Change

12. Thank You!