FRONTIERS - Scientists from the US measured the relative amounts of ‘bioreactive’ iron in four sediment cores from the bottom of the Atlantic. They showed for the first time that the further dust is blown from the Sahara, the more iron in it becomes bioreactive through chemical processes in the atmosphere. These results have important implications for our understanding of the growth-promoting effect of iron on oceanic phytoplankton, terrestrial ecosystems, and carbon cycling, including under global change.
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“Our results suggest that during long-distance atmospheric transport, the mineral properties of originally non-bioreactive dust-bound iron change, making it more bioreactive. This iron then gets taken up by phytoplankton, before it can reach the bottom,” said Dr. Timothy Lyons, a professor at the University of California at Riverside and the study’s final author.
“We conclude that dust that reaches regions like the Amazonian basin and the Bahamas may contain iron that is particularly soluble and available to life, thanks to the great distance from North Africa, and thus a longer exposure to atmospheric chemical processes,” said Lyons.