The world’s largest rainforest and a crucial store of carbon dioxide gets most of its phosphorous, an important nutrient, from an unexpected source: fires in Africa. Strange as it may seem, we thought that the Amazon got much of its phosphorus from dust whipped up from the Sahara Desert and transported across the Atlantic on the wind.
Cassandra Gaston at the University of Miami, US, and her colleagues had set out to quantify the effect of the phosphorous in Saharan dust on the Amazon’s growth. To do this, they collected and analysed particles caught in filters from a hilltop in French Guiana, at the northern edge of the Amazon Basin. But at the same time, they used satellites to track smoke from fires in Africa — both people burning wood and natural forest fires — drifting Westwards across the ocean. It turned out that the arrival of patches of smoke coincided with high levels of phosphorous being detected in the filters. Gaston and her team then estimated how much of the phosphorus deposited on the Amazon Basin comes from African biomass burning. They found that, in Spring, smoke from the fires was responsible for most of the nutrient entering the Amazon Basin. …The findings suggest that people burning wood and other materials in Africa might have an impact on how much the Amazon grows and therefore how much carbon it stores in future.
Excerpt from The Amazon rainforest depends on fires in Africa for a vital nutrient, New Scientist, July 29, 2019