Acidic seas threaten coral and mussels
Rising carbon dioxide levels are increasing acidity in the oceans 10 times faster than scientists thought, posing a greater threat to shell-forming creatures such as coral and mussels.
An eight-year project in the Pacific has found that rising marine acid levels will challenge many organisms, because their shell-making chemistry is critically dependent on a less acidic, more alkaline environment. The study monitored seawater pH levels at the north-east Pacific island of Tatoosh off Washington state in the United States.
Timothy Wootton, from Chicago University, said scientists found that acidity levels increased at more than 10 times the rate predicted by computer models designed to study the link between atmospheric concentrations of carbon dioxide and ocean acidity.
Atmospheric carbon dioxide levels have increased by about 100 parts per million since the start of the industrial revolution and are now at their highest point in at least 650,000 years.
About a third of man-made carbon dioxide emissions has dissolved into the oceans. As carbon dioxide dissolves in seawater, it forms carbonic acid, which lowers the ocean's alkalinity and pH level, making it more acidic.
The Intergovernmental Panel on Climate Change (IPCC) predicted last year that most coral reefs would disappear by the century's end because of rising temperatures and ocean acidity.