Scientific American: Plankton, tiny marine organisms, are a good way of cleansing the atmosphere of one of the main greenhouse gases, carbon dioxide. To do this they need dissolved iron to help them to grow, and if they lack iron then they cannot do much to reduce CO2 levels.
So the eruption in 2010 of an Icelandic volcano gave scientists a perfect opportunity to see how much the cataclysm helped the plankton by showering them with unexpected clouds of iron.
Their verdict, published in the journal Geophysical Research...