In 2008, a team, led by oceanographer Roberta Hamme, University of Victoria, Canada, happened to be in the right place when a large phytoplankton bloom in the North pacific was triggered by an ash cloud from one of the Aleutian volcanoes. Yet, although large amounts of iron were absorbed by the phytoplanton, the net effect on carbon dioxide absorption was minimal. Seeding the oceans with iron, therefore, will not be the solution to reverse the carbon dioxide increase, the team concludes in a recent paper in Geophysical Research Letters.

Hamme, R. C., et al. (2010), Volcanic ash fuels anomalous plankton bloom in subarctic northeast Pacific, Geophys. Res. Lett., 37, L19604, doi:10.1029/2010GL044629.