Link Between Dust, Plankton, And Cooling Probed in Research

New research by Swiss scientists shows a strong correlation over the past 4 million years between the amount of iron-rich dust in the oceans — which fertilizes plankton growth — and periods of global cooling and glaciation. Researchers at the Swiss Federal Institute of Technology, examining marine sediment cores in the South Atlantic that reveal climate conditions dating back 4 million years, said that dust levels in the ocean have been twice as high during deep glaciations as during warmer periods. The Swiss scientists said that when large amounts of iron-rich dust blow from Central Asia and other parts of the globe and are deposited in the sea — particularly in the Southern Ocean surrounding Antarctica — the iron stimulates the growth of phytoplankton. Those phytoplankton blooms absorb large amounts of carbon dioxide from the water, enabling the oceans to then absorb even more carbon from the air, which cools the planet. The finding, reported in the journal Nature, adds support to the idea that seeding the oceans with iron could be one way to stimulate phytoplankton blooms and cool the planet by removing some of the atmospheric CO2 generated by human activity.