02 Mar 2012: Ocean Acidifying Faster Than
Any Time in 300 Million Years, Study Says

The world’s oceans may be acidifying faster today than during any period over the last 300 million years, a phenomenon that could have dire consequences for many marine species and ecosystems, according to a new study. In a review of hundreds of paleoceanographic studies, a team of international scientists found that a steep rise in atmospheric levels of carbon dioxide has driven down pH levels in the oceans by 0.1 over the last century, to about 8.1, a rate 10 times faster than the closest historical comparison — a period of acidification 56 million years ago that triggered a massive ocean die-off. The oceans are vulnerable because they absorb excess carbon dioxide from the atmosphere, turning the water more acidic, which can inhibit organisms, such as oysters and coral reefs, from forming shells. “We know that life during past ocean acidification events was not wiped out — new species evolved to replace those that died off,” said Barbel Honisch, a paleoceanographer at Columbia University’s Lamont-Doherty Earth Observatory and lead author of the study, published in Science. “But if industrial carbon emissions continue at the current pace, we may lose organisms we care about — coral reefs, oysters, salmon.” Some scientists believe that oyster larvae die-offs along the west coast of the U.S. and Canada are related to increasingly acidic waters in that region.