When ocean water becomes so acidic it dissovles aragonite, shelled organisms fail. Such aragonite undersaturated areas of the Arctic Ocean are rapidly increasing in depth and expanse.
By 2010, the undersaturated area had expanded from 5 percent to about 31 percent of the water column, the study suggests. And the scientists found undersaturation at up to 250 meters deep and in locations above 85 degrees North latitude. In other words, the acidifying zone had expanded both northward into the Arctic Circle and deeper into the water. The researchers point out that the levels of aragonite in these areas are below the point scientists believe is a threat to marine organisms.
... the researchers decided to conduct a model simulation to see how Arctic acidification might progress in the future.
... 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. [emphasis mine]