British and Australian researchers have found that one of the world’s largest carbon sinks, the Southern Ocean, stores carbon differently to first thought.
The Southern Ocean contains about 40 per cent of all carbon dioxide emissions absorbed by the world’s oceans.
Researchers examined the way the Southern Ocean sucks carbon absorbed from the surface layer into the deeper ocean.
They found that currents limit the ocean’s ability to absorb carbon in the first place and that it is being released sooner than previously thought.
Research co-author Richard Matear from the CSIRO says the deep currents which draw carbon into the ocean actually vent it upwards in some areas.
“A conventional thought would be that once it gets out of this surface layer, it’s kind of been tucked away and won’t appear for a long time; many years of hundreds of years,” he said.
“But with this re-ventilation, there’s some places where actually it doesn’t get put away into the deep ocean for long at all, re-ventilating in the time-scale of a decade.”
He says the findings have practical applications.
“There’s a recent study, for example, that talks about trying to enhance the uptake of carbon by the Southern Ocean by fertilising with iron.”
“By combining these two pieces of information it actually makes you think about where in the Southern Ocean you could actually implement something like iron fertilisation to enhance carbon uptake because you’d want to avoid these places where you have re-ventilation.”
The research has been published in the journal Nature Geoscience.