Rapid growth in acidity in the Arctic ocean linked to climate change

The Arctic is suffering so many consequences related to climate change, it’s hard to know where to begin anymore. It’s warming more rapidly than almost any other part of the planet; its glaciers are melting and its sea ice is retreating; and its most iconic wildlife, including polar bears and walruses, are suffering.

But that’s not all — a new study, just out Monday in the journal Nature Climate Change, indicates that the Arctic Ocean is also becoming more acidic, another consequence caused by greenhouse gases in the atmosphere. It’s a process that occurs when carbon dioxide dissolves out of the air and into the sea, lowering the water’s pH in the process.

Scientists believe acidification is occurring at varying rates all over the world. But this week’s study gives researchers renewed cause to worry about the Arctic, suggesting that a large — and increasing — swath of the ocean may have reached a level that’s dangerous for some marine organisms.

The new research focuses on the water concentrations of a mineral called aragonite, which is a form of calcium carbonate, a chemical compound that plankton, shellfish and even deep-sea corals use to build their hard outer shells. When ocean water becomes more acidic, chemical reactions occur that impede the formation of calcium carbonate and lower its concentration in the water, which can be a major threat for these marine animals.

These aragonite levels are a “very important parameter” which can be an indicator of how much carbon dioxide is dissolving into the sea, according to Liqi Chen, a scientist with China’s State Oceanic Administration and a co-author on the new study.

By analyzing data collected from the ocean during expeditions between 1994 and 2010, the scientists have found that some parts of the western Arctic Ocean are undersaturated with aragonite — in other words, their concentrations are lower than they could be. And these areas have expanded more than sixfold since the 1990s.

. . . “Models indicate that sea ice will continue to decrease and the prediction is that the Arctic Ocean may be ice-free in the summer by 2030,” they write. If this occurs, their projections suggest that the entire surface of the Arctic Ocean, up to about 30 meters deep, may be undersaturated with aragonite within two decades. And given the rate of expansion they’ve observed since 1994, they suggest that the entire western Arctic Ocean — up to 250 meters deep — could also become undersaturated within a few decades. . .

Featured Image: Ice floes in Baffin Bay above the Arctic Circle, seen from the Canadian Coast Guard icebreaker Louis S. St-Laurent, in July 2008. (Jonathan Hayward/Canadian Press via AP)


Scientists just measured a rapid growth in acidity in the Arctic ocean, linked to climate change

February 27, 2017

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