Study Finds African Smoke Is Fertilizing Amazon Rainforest and Oceans

Research has important implications to better understand Earth’s climate. (Image: via pixabay / CC0 1.0)

A new study led by researchers at the University of Miami’s (UM) Rosenstiel School of Marine and Atmospheric Science found that smoke from fires in Africa may be the most important source of a key nutrient — phosphorus — that acts as a fertilizer in the Amazon rainforest, tropical Atlantic, and Southern oceans.

Nutrients found in atmospheric particles, called aerosols, are transported by winds and deposited to the ocean and on land where they stimulate the productivity of marine phytoplankton and terrestrial plants leading to the sequestration of atmospheric carbon dioxide. The study’s senior author, Cassandra Gaston, an assistant professor in the Department of Atmospheric Sciences at the UM Rosenstiel School, said:

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To conduct the study, the researchers analyzed aerosols collected on filters from a hilltop in French Guiana, at the northern edge of the Amazon Basin, for mass concentrations of windborne dust and their total and soluble phosphorus content.

They then tracked the smoke moving through the atmosphere using satellite remote sensing tools to understand the long-range transport of smoke from Africa during time periods when elevated levels of soluble phosphorus were detected. They were then able to estimate the amount of phosphorus deposited to the Amazon Basin and the global oceans from African biomass burning aerosols using a transport model.


The analysis concluded that the smoke from widespread biomass burning in Africa, mostly the result of land clearing, brush fires, and industrial combustion emissions, is potentially a more important source of phosphorus to the Amazon rainforest and Tropic Atlantic and Southern oceans than dust from the Sahara Desert. UM Rosenstiel School graduate student Anne Barkley, lead author of the study said:

Gaston added:

The study, titled “African biomass burning is a substantial source of phosphorus deposition to the Amazon, Tropical Atlantic Ocean, and Southern Ocean,” was published on July 29, 2019, in the Proceedings of the National Academy of Sciences.

Provided by: Diana Udel, University of Miami [Note: Materials may be edited for content and length.]

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