Smoke from tropical fires carries key nutrients to the heart of the Amazon

An international team of researchers, led by Catalan experts from CREAF, the CSIC and the University of Antwerp, has shown that smoke generated by forest fires in tropical regions can travel thousands of kilometres and reach the heart of the Amazon rainforest. This smoke carries phosphorus, an essential nutrient for tree growth, and its arrival can help offset the carbon loss caused by deforestation and the fires themselves.

The study, published in the journal Nature Geoscience, indicates that the phosphorus reaching the Amazon provides an additional nutrient input. According to Adrià Descals, the principal researcher, this phenomenon results in increased photosynthesis and leaf growth, allowing trees to capture more atmospheric carbon. For every additional milligram of phosphorus per square metre, 7.4 more grams of carbon are stored. However, the experts warn that this effect does not fully offset the emissions and ecological losses associated with fires and deforestation.

Most forest fires are concentrated in the south of the Amazon, in the so-called “arc of deforestation”, where logging and fire transform the rainforest into agricultural land. The smoke generated in this area can travel long distances, depositing phosphorus and other aerosols on the forest through rain or ash that falls to the ground.

The study’s findings underline the strong interconnection between ecosystems. While fires release large quantities of carbon locally, the resulting smoke and pollution can increase the carbon dioxide absorption capacity of forests located thousands of kilometres away.

To reach these conclusions, the scientists analysed satellite data on the photosynthetic activity of vegetation over 20 years, combined with field measurements and atmospheric models simulating the long-distance transport of smoke. Areas of rainforest receiving more smoke show significantly greater productivity.