1. Ocean Acidification Discussion Catherine Bacon 1.28.15

2. Anthropogenic Green House Gas Emissions The World Metrological Organization (WMO) claims that long-lived green house gas (LLGHG) concentrations reached new post-industrial revolution highs in 2013 The concentration of CO 2 in the atmosphere was measured to be 396.0 ppm in 2013 The oceans serve as a carbon sink where ¼ of all anthropogenic CO 2 is absorbed by the oceans.

3. Mechanisms of Ocean Acidification The oceans serve as a sink for 25% of anthropogenic CO 2 emissions The presence of carbonate (CO 3 2- ) in the oceans act as a buffer in this reaction The ocean’s buffering capacity is currently at 70% of its pre- industrial levels

6. Effects of Ocean Acidification Measurable increase in oceanic acidity has already been recorded. (0.1 unit lower than pre-Industrial pH) If current emission rates are maintained, pH will be 0.3-0.4 units lower by the end of the century. Coral and some plankton will have difficulty forming and maintaining shells due to the decrease in carbonate ions. Plankton are used as indicators of overall ecosystem health in some artic regions and are the base of many oceanic food webs. If pteropods are excluded from their native regions, their predators will be immediately affected.

7. Shell Formation and Dissolution In pteropods, carbonate, specifically aragonite, plays an important role in shell formation which occurs via calcification. In water undersaturated with respect to aragonite, shell dissolution occurs in pteropods. Dissolution begins with the formations of pits in the pteropod’s shell. 14 individuals tested in undersaturated water showed pits in their shells where the shell thickness was <1 μm where it is typically ~7 μm thick