Shellfish could be wiped out as the Arctic Ocean acidifies due to climate change, scientists have warned.

Researchers say the Arctic Ocean will absorb more carbon dioxide than expected in the next 80 years, increasing the acidity of the water.

This could wipe out organisms such as shellfish, urchins and sea butterflies as the acid can dissolve their calcified skeletons and shells.

The Arctic Ocean will absorb more CO2 as it has conditions favourable for the formation of so-called deep water.

This occurs when the air temperature drops and the ocean's surface waters are extra salty. This makes the water denser, causing it to sink and increasing the transport of CO2 to the ocean's depths.

Lead researcher Dr Jens Terhaar of the University of Bern in Switzerland said the results, published in the journal Nature, showed the Arctic Ocean will 'take up 20 per cent more CO2 over the 21st century than previously expected'.

Acidification would particularly hit waters in the 200 to 1,000m depth range – an 'important refuge area for many marine organisms'.

The researchers compared the sea-surface information and simulations of deep-water formations used in current climate models.

They found there was a 'large divergence' when it came to predicting the Arctic Ocean's Carbon intake over the next eighty years.

The team then used sea-surface water density measurements to correct the models' bias and reduce uncertainty around future levels of acidification.

Co-author Dr Lester Kwiatkowski, at the École normale supérieure in Paris, said: 'Our results suggest that it will be more difficult for Arctic organisms to adapt to ocean acidification than previously expected.

'A loss of these organisms is likely to impact the entire Arctic food chain up to fish and marine mammals.'