The researchers say the Nordic Seas are acidifying over a wide range of depths - most quickly in surface waters and more slowly in deep waters.

BBC: Arctic Ocean 'acidifying rapidly'

The Arctic's vulnerability is exacerbated by increasing flows of freshwater from rivers and melting land ice, as freshwater is less effective at chemically neutralising the acidifying effects of CO2.

BBC: Arctic Ocean 'acidifying rapidly'

But the true meaning of the Anthropocene is that we have affected nearly every aspect of our environment from a warming atmosphere to the bottom of an acidifying ocean.

FORBES: On The Anthropocene Age