A piece of Africa—actually lots of them—began to arrive in the Americas in June 2014. On June 23, a lengthy river of dust from western Africa began to push across the Atlantic Ocean on easterly winds. A week later, the influx of dust was affecting air quality as far away as the southeastern United States.
This composite image, made with data from the Visible Infrared Imaging Radiometer Suite (VIIRS) on Suomi NPP, shows dust heading west toward South America and the Gulf of Mexico on June 25, 2014. The dust flowed roughly parallel to a line of clouds in the intertropical convergence zone, an area near the equator where the trade winds come together and rain and clouds are common. In imagery captured by the Moderate Resolution Imaging Spectroradiometer (MODIS), the dust appeared to be streaming from Mauritania, Senegal, and Western Sahara, though some of it may have originated in countries farther to the east.
Saharan dust has a range of impacts on ecosystems downwind. Each year, dust events like the one pictured here deliver about 40 million tons of dust from the Sahara to the Amazon River Basin. The minerals in the dust replenish nutrients in rainforest soils, which are continually depleted by drenching, tropical rains. Research focused on peat soils in the Everglades show that African dust has been arriving regularly in South Florida for thousands of years as well.
In some instances, the impacts are harmful. Infusion of Saharan dust, for instance, can have a negative impact on air quality in the Americas. And scientists have linked African dust to outbreaks of certain types of toxic algal blooms in the Gulf of Mexico and southern Florida.
Floridians looking for a break from hurricane season in late July 2005 were in for a change, though it wasn’t necessarily what they wanted: Saharan dust. By July 19, a massive dust storm had crossed the Atlantic towards southern Florida. This image, captured by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument, shows wide swaths of the planet. On the right is the Sahara Desert, Earth’s biggest dust-producing machine. In the far upper left is North America, this dust storm’s likely target. In the center of the picture, intermixed with clouds, is the swirling dust storm, nearly the size of the United States.
Saharan dust hovered over the Atlantic for several days in mid-January 2008. This image shows two different areas of dust plume activity. Immediately off the coasts of Western Sahara and Mauritania, a series of tan dust plumes blow in predominantly straight lines toward the northwest. Farther west, a large, diffuse plume of dust hangs over the Atlantic Ocean