London: Atmospheric carbon dioxide levels shot up by nearly 50 per cent at the end of the last ice age because ancient oceans belched stagnant CO2 into the skies, scientists have found.
Signs of stagnant CO2-rich water have been discovered 3700 metres beneath the Southern Ocean’s seabed, between Antarctica and South Africa, reports New Scientist.
Stewart Fallon of the Australian National University in Canberra and his colleagues collected samples from drill cores of the marine crust of tiny marine fossils called foraminifera.
Different species of these lived at the surface and the bottom of the ocean.
The chemical composition of their shells is dependent on the water they form in and how much CO2 it contains.
The team found that species of foraminifera living on the sea floor around the time of the ice age contained more carbon than those that floated at the surface.
They also found this discrepancy disappeared around 19,000 years ago, which is also when the ice sheets began to melt.
The study has appeared in the journal Science.