Easterly trade winds blow this dust across the Atlantic Ocean. depositing about 40 million tons of dust each year onto the Amazon region of South America. This dust is a significant source of nutrients for the Amazon forests helping to counteract the strong leaching effect of heavy rainfall in these regions. Much of the Saharan dust is deposited in the Atlantic Ocean as it is carried toward organisms that form the base of the oceanic South America where it fertilizes the phytoplankton food chain. ocean water tends to be iron-deficient and it is believed that the Saharan dust replen- ishes nutrient iron in regions of the Atlantic where it is deposited.