New Scientist Magazine reports:
Alfredo Martinez-Garcia at the Swiss Federal Institute of Technology in Zurich and colleagues have used marine sediment cores taken from an area of the Atlantic Ocean just north of the Southern Ocean to look back 4 million years. They say dust levels have been twice as high during deep glaciations throughout that time (Nature, DOI: 10.1038/nature10310).Dust contains some iron particles. The iron in the particles can promote plankton growth.
"Dust deposition in the Southern Ocean increased with the emergence of the deep glaciations that characterise the late Pleistocene," says Martinez-Garcia.
When blown into the sea, the iron it contains can fertilise plankton growth on a scale large enough to cause global temperatures to drop. The finding adds support to the idea of staving off climate change by simulating the effects of dust - perhaps by sprinkling the oceans with iron filings.Thanks Michael Trigoboff
Iron-rich dust falling on the ocean has long been known to spark blooms of plankton, and researchers suspect the process could have intensified the ice ages that have occurred over the past few million years.