Ocean Acidfication

Due to greenhouse gas emissions, the ocean has absorbed enough atmospheric CO2 to reduce the pH of the ocean surface by 0.1 logarithmic pH units, corresponding to a ~30% increase in ocean acidity . This poses several challenges to ocean organisms, particularly those that make calcium carbonate structures like corals, snails, and oysters. With more carbonate ions binding to excess H+ ions due to acidification, these organisms cannot make such structures. At high enough acidity levels, levels predicted to be reached by the year 2100, these calcified structures dissolve. In addition, increased ocean acidity has been shown to reduce the ability of some fish to detect predators and suitable habitat.

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GLODAP

Global Ocean Data Analysis Project (GLODAP) is a project that aggregates biogeochemical data derived by the chemical analysis of water samples from 1,108 cruises, with a goal to increase accessibility to these data. These data originate from stations across the globe, in which a total of 13 variables are measured, including nitrate levels, alkalinity, and pH.

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The pH measurements from the Arctic, Atlantic, Indian, and Pacific oceans by month from the GLODAP dataset. Lines of best fit are plotted for each ocean, where each besides the Arctic ocean has a negative slope. The overall trend is clearly sloped downward, indicating an acidification of the Earth’s oceans.