By Janet Raloff
Efforts to remove climate-warming carbon dioxide from Earth’s atmosphere appear to be getting a helping hand from a surprising source: the iron in meltwater from Antarctic icebergs.
Icebergs calving off of Antarctica are shedding substantial iron — the equivalent of a growth-boosting vitamin — into waters starved of the mineral, a new set of studies demonstrates. This iron is fertilizing the growth of microscopic plants and algae, transforming the waters adjacent to ice floes into teeming communities of everything from tiny shrimplike krill to fish, birds and sometimes mammals.
To grow, these plants and animals use carbon drawn into the water from carbon dioxide in the atmosphere. Some share of this carbon will eventually be excreted as wastes that fall to the ocean floor, essentially removing it as a near-term climate risk.