Ocean Acidification: Another Undesired Side Effect Of Fossil Fuel-burning

Since the industrial revolution, the oceans have become 30 percent more acidic (from 8.2 pH to 8.1 pH). “Under a “business as usual scenario, predictions for the end of the century are that we will lower the surface ocean pH by 0.4 pH units, which means that the surface oceans will become 150 percent more acidic — and this is a ‘hell of a lot’ “, said Jelle Bijma, chair of the EuroCLIMATE programme Scientific Committee and a biogeochemist at the Alfred-Wegener-Institute Bremerhaven.

“Ocean acidification is more rapid than ever in the history of the earth and if you look at the pCO2 (partial pressure of carbon dioxide) levels we have reached now, you have to go back 35 million years in time to find the equivalents” continued Bijma.
A maximum allowed change in pH, where the system is still controllable, needs to be found. This is a major challenge considering the multifaceted unknowns that still are to be clarified. This so-called “tipping point” is currently estimated to allow a drop of about 0.2 pH units, a value that could be reached in as near as 30 years. More research and further modeling needs to be undertaken to verify the predictions.

The expected biological impact of ocean acidification remains still uncertain. Most calcifying organisms such as corals, mussels, algae and plankton investigated so far, respond negatively to the more acidic ocean waters. Because of the increased acidity, less carbonate ions are available, which means the calcification rates of the organisms are decreasing and thus their shells and skeletons thinning. However, a recent study suggested that a specific form of single-celled algae called coccolithophores actually gets stimulated by elevated pCO2 levels in the oceans, creating even bigger uncertainties when it comes to the biological response.

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