“Trouble in paradise: can shell recycling help buffer the effects of ocean acidification?” – Google Science Fair finalist

Google announced the finalists for its annual international science fair on Tuesday, with projects from all over the world covering a wide variety of fields — all, of course, by scientists under 18 years old. Isabella O’Brien of Canada, aged 13, came up with a way to reuse waste products to help the environment. She wants to grind up the many, many tons of shells left over from the seafood industry to reduce ocean acidification.

Photo credit: I. O'Brian

Photo credit: I. O’Brian

This experiment was designed to establish if adding crushed shells, which are 95% calcium carbonate, to seawater, would act as an alkaline buffer to mitigate the effects of ocean acidification. It was hypothesized that mussel, clam and oyster shell deterioration in seawater at pH 7.5 would be reduced by adding powdered shells to the acidic test solution. It was also hypothesized that the addition of the shell powder would stabilize the pH levels.

The average weight reduction of each shell in treated and untreated solutions showed that the addition of powdered shells decreased the rate of shell degradation, and thus mitigated the effects of ocean acidification. Therefore, the experiment’s hypothesis was supported. Also, the pH in the acidified seawater with added powdered shells either stabilized or increased over each two-week period. This illustrates that the calcium carbonate from the shell powder was acting as an alkaline buffer in the acidified seawater.

In conclusion, it appears that the adding of recycled crushed shells to the independent variable (the solutions) has a direct and expected effect on the dependent variable (the average reduction in the weight of shells and the average pH over time). Therefore, recycling waste shells produced by the seafood industry, crushing them to allow for easier breakdown and absorption, and returning them to the ocean, should be investigated as a method to slow the harmful effects of ocean acidification.

Detailed description of the project.

More information on the Google Science Fair.

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