Natural Iron Fertilization: Sahara Dust Storms Stimulate Huge Plankton Blooms
Because of the controversy iron fertilization has managed to stir up over the past year (see Planktos' ill-fated efforts), many people probably still don't realize that it can be a natural process - and one that is likely to become more frequent due to climate change. The eastern Atlantic Ocean, for example, is often characterized by large phytoplankton blooms; the source of iron is the aeolian dust that blows off the coast of Africa from the Sahara desert.
Replete with nitrogen, phosphorus and iron - amongst other nutrients - the dust essentially acts as a fertilizer to stimulate the production of large blooms. Eric Achterberg, a scientist at the University of Southampton's National Oceanography Center, is leading a research expedition to study the effect of the large quantities of dust on phytoplankton blooms and the amount of nutrients present - which, at close to 500m tons per year, are enough to affect climate change. The dust particles help encourage cloud formation and - by partly absorbing and reflecting sunlight - help reflect light back into space. Moreover, the particles also heat the air while cooling the ocean surface.
In a recent BBC News piece, Achterberg explained to Rebecca Morelle: "If these organisms grow, they take up more carbon dioxide and remove it from the atmosphere. If we understand how the dust functions here, we will have a better idea of how the ecosystem in the North Atlantic takes up carbon dioxide, how quickly it takes it up and how this changes over time."
Many scientists believe aeolian dust transport will become more frequent over the coming years as a result of increased land-use and desertification. How much of an effect these dust storms will have on significantly mitigating climate change - if any - over the long term remains to be seen; ongoing research in the Atlantic Ocean and other regions of the world will hopefully determine the extent of the effect of iron fertilization.
Image courtesy of National Oceanography Centre, Southampton