image: These are phytoplankton grown in the lab with no iron (leftmost bottle), iron from nonglacial dust (second and third from left), and iron from glacial dust (fourth and fifth from left), showing that the chemical form of iron in glacial dust supports higher growth than that in nonglacial dust. view more
Credit: Elizabeth M. Shoenfelt
A study of marine sediments in the South Pacific and South Atlantic finds that during glacial periods the proportion of bioavailable iron in glacially-produced dust transported to the Southern Ocean, which supports phytoplankton growth and subsequent removal of carbon dioxide in the form of organic matter, is 25-45% of iron in dust, whereas in interglacial periods the proportion is around 5-10%, suggesting that glacial dust can serve as a positive climate feedback by removing atmospheric carbon dioxide during glacial periods.
Article #18-09755: "Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods," by Elizabeth M. Shoenfelt, Gisela Winckler, Frank Lamy, Robert F. Anderson, and Benjamin C. Bostick.
MEDIA CONTACT: Elizabeth M. Shoenfelt, Columbia University's Lamont-Doherty Earth Observatory, Palisades, NY; tel: 845-365-8328; e-mail: shoen@ldeo.columbia.edu
###
Journal
Proceedings of the National Academy of Sciences