An expedition to Antarctica reveals that iron supply to the Southern Ocean may have controlled Earth’s climate during past ice ages.
Previous studies have suggested that during the last four ice ages, the Southern Ocean had large phytoplankton populations and received large amounts of iron-rich dust, possibly blown out to sea from expanding desert areas. Each of these blooms consumed over 30,000 tons of carbon dioxide. Observations indicate that much of the carbon sank to hundreds of meters below the surface. This finding suggests that iron fertilization could cause billions of tons of carbon to be removed from the atmosphere each year.