Los Angeles -- U.S. scientists say they have discovered iron "dust" can not only be carried to the ocean by rivers or blown to sea, but can also rise from the ocean floor.
Researchers found iron dust -- the rarest nutrient for most marine life -- can float up from the sea floor in material spewed from hydrothermal vents.
Scientists from the University of Southern California, University of Minnesota, Woods Hole Oceanographic Institution and Lawrence Berkeley National Laboratory took samples from the East Pacific Rise, a volcanic mid-ocean ridge.
Brandy Toner of the University of Minnesota, the lead author of the research, said the scientists found organic compounds capture some iron from hydrothermal vents, enabling it to be carried away in seawater,
The researchers noted iron trapped in such a fashion does not rust.
"Everything we know about the chemical properties of iron tells us that it should be oxidized; it should be rusted," said Katrina Edwards of USC, adding the metal's purity has practical value since aquatic organisms metabolize pure iron more easily than its rusted form.
Edwards said exactly how much captured iron floats into surface waters remains unknown, but any that does would nourish ocean life more efficiently than the oxidized iron from regular sources.
The discovery appears online in the journal Nature Geoscience.
Copyright 2009 by United Press International.