This past summer, 35 oceanographers and marine biologists from Europe and Asia trekked to Norway’s
Spitsbergen island, about 750 miles from the North Pole. Then they kept going, right into the water, and set up an elaborate system of underwater test tubes. Their mission was to study how the abundant marine life in these frigid waters will bear up under the stress of one of the world’s most daunting, if least publicized, environmental threats: the rising acidity of the oceans.
As carbon dioxide levels in the atmosphere increase, the seas absorb greater amounts of the gas, which reacts with water to form carbonic acid. Surface waters today are 30 percent more acidic, on average, than they were at the start of the Industrial Revolution. And unlike the storms, droughts, and heat waves that might be spawned by climate change—which are difficult to measure and predict—ocean acidification advances with disconcerting regularity. The most conservative models forecast that
the ocean will be twice as acidic as in preindustrial times by the end of this century. “In the past 200 years, we have manipulated seawater chemistry at a rate that has not occurred for at least 20 million years,” says oceanographer Jean-Pierre Gattuso, coordinator of the European Project on Ocean Acidification (EPOCA) and a lead scientist on the Spitsbergen experiments.
Previous episodes of acidification—
possibly caused by CO2 released from huge, sustained volcanic eruptions—had a tremendous ecological impact. “We know that past acidification events played a role in mass extinctions, when lots of animals and plants disappeared from the ocean,” Gattuso says. “Life is flexible, so some organisms were able to adapt and evolve. The worry today is that the change is happening so fast that many may not have time to adjust.”
The science of how soured waters will affect marine life is still young, but the evidence so far suggests that the hardest hit will be organisms that have shells or skeletons built from calcium carbonate, including corals, mollusks, and many plankton. Acids dissolve carbonate, so as pH levels in the world’s oceans drop, these animals may have trouble maintaining their body parts.