Increased Ocean Acidification Rate Puts Polar Ecosystems at Risk
An assessment of ocean acidification, presented at the UN Climate Change Conference in Warsaw in November 2013, starkly concluded that acidity is on track to rise 170 percent by the end of this century. As many key species are sensitive to changes in acidity, this would drastically impact ocean ecosystems, with effects especially pronounced in polar regions where the cold waters intensify acidification, and which is home to many organisms that are particularly vulnerable to acidification.
The ocean acts as a giant sink for carbon, absorbing 24 million tons of CO2 from the atmosphere every day. Since industrialization, approximately 30 percent of anthropogenic (human generated) CO2 has been absorbed in this way. In the context of climate change this is incredibly important, as the amount of atmospheric CO2 is directly linked to global temperatures. But as CO2 is absorbed, the pH of the water decreases, and it becomes more acidic. Compared with pre-industrial levels, the ocean’s acidity has soared 26 percent, and will only increase as CO2 emissions rise. Not only will this likely injure marine ecosystems, but the more acidic the water becomes the less it is capable of absorbing carbon, thereby exacerbating CO2 emissions.
In addition to ecosystem damage, ocean acidification could bring about significant economic losses.
"People who rely on the ocean's ecosystem services — often in developing countries - are especially vulnerable," stated a press release by the International Council for Science.
The report's authors represented the largest-ever gathering of ocean acidification scientists, with 540 experts representing 37 countries contributing to the discussion of acidification research. They found that the current rate of acidification is unprecedented, and is ten times faster than at any other time in the last 55 million years.
With the changing chemistry of the oceans comes a myriad of cascading effects. Coral reefs may start to erode faster than they are being built. Species that rely on calcification to build their shells and skeletons — using forms of calcium carbonate — may find acidic waters too corrosive to survive. This means the shellfish industry will likely suffer as mollusks (including mussels and oysters) are among the organisms most sensitive to acidification. And with other factors also changing at the same time, such as temperature, overfishing, and pollution levels, the cumulative effects are likely to be even more pronounced.
"Multiple stressors compound the effects of ocean acidification," the authors wrote.
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Ocean image via Shutterstock.