Fertilizing the Amazon and equatorial Atlantic with West African dust

Atmospheric mineral dust plays a vital role in Earth's climate and biogeochemical cycles. The Bodele Depression in Chad has been identified as the single biggest source of atmospheric mineral dust on Earth. Dust eroded from the Bodele is blown across the Atlantic Ocean towards South America. The mineral dust contains micronutrients such as Fe and P that have the potential to act as a fertilizer, increasing primary productivity in the Amazon rain forest as well as the equatorial Atlantic Ocean, and thus leading to N-2 fixation and CO2 drawdown. We present the results of chemical analysis of 28 dust samples collected from the source area, which indicate that up to 6.5 Tg of Fe and 0.12 Tg of P are exported from the Bodele Depression every year. This suggests that the Bodele may be a more significant micronutrient supplier than previously proposed. Citation: Bristow, C. S., K. A. Hudson-Edwards, and A. Chappell (2010), Fertilizing the Amazon and equatorial Atlantic with West African dust, Geophys. Res. Lett., 37, L14807, doi:10.1029/2010GL043486.