Iron-rich melting ice sheets could slow global warming

As forests disappear and ice melts, concerns over climate change continue to rise but scientists have now discovered a new source of oceanic "bio-available" iron that could help buffer the effects of global warming.

Summer meltwaters from ice sheets are rich in iron and they could lead to growth of phytoplankton, microscopic plant-like organisms that consume carbon dioxide and release oxygen, the findings showed.

It is well known that bio-available iron boosts phytoplankton growth in many of the earth's oceans.

In turn, phytoplankton capture carbon - thus buffering the effects of global warming.

The plankton also feed into the bottom of the oceanic food chain, thus providing a food source for marine animals.

The Greenland and Antarctic ice sheets cover around 10 percent of global land surface. Iron exported in icebergs from these ice sheets has been recognised as a source of iron to the oceans for some time.

"Our finding that there is also significant iron discharged in runoff from large ice sheet catchments is new," said Jon Hawkings from the University of Bristol.

"This means that relatively high iron concentrations are released from the ice sheet all summer, providing a continuous source of iron to the coastal ocean," he noted.

The researchers collected meltwater discharged from Leverett Glacier in Greenland over the summer of 2012, which was subsequently tested for bio-available iron content.

The water exiting from beneath the melting ice sheet contained significant quantities of previously unconsidered bio-available iron, the findings showed.

This means that the polar oceans receive a seasonal iron boost as the glaciers melt.

The findings appeared in the journal Nature Communications.