Ocean acidity threatens shellfish

The acidity of the world's oceans is increasing more rapidly than climate change models had predicted, reported the Guardian, citing a study published in the US journal Proceedings of the National Academy of Sciences. Scientists warn rising acid levels will have a detrimental impact on marine ecosystems and shellfish populations.


An analysis of water samples collected over the past eight years around Tatoosh Island in the eastern Pacific indicates that the seawater has acidified more than 20 times faster than scientists expected. Acidic water is extremely harmful to shellfish and other crustaceans because it dissolves the calcium carbonate that is the main component of their protective shells.


Based on computer modelling, scientists predict that the rise in acidity is likely to cause substantial drops in the populations of mussels and large goose barnacles, while algae and the number of smaller barnacles may rise. These kinds of population shifts are predicted to have a significant effect on the marine ecosystem, especially those organisms at the bottom of the foodchain.


About a third of the carbon dioxide (CO2) released into the atmosphere by human activities is taken in by the world’s oceans. When the CO2 is absorbed into the water, it forms carbonic acid, which alters the ocean’s natural pH level.