Indeed, this is one of the most unlikely connections on Earth, but the satellite in question has captured images of massive dust clouds being transported high in the atmosphere. These dust clouds transport significant amounts of phosphorus from Sahara, one of the most desolate places on our planet, to the Amazon, one of the most fertile. Of course, the large amounts of phosphorus are a remnant from when the desert’s past as a lake.
“Even tens of millions of years after South America separated from Africa, the two continents are still inextricably linked, like an older brother and a younger brother,”
Charlie Zender, climate scientist, said.
While scientists had long been aware of the fact that dust winds were capable of transporting large amounts of nutrients and phosphorus trans-continentally, no one had anticipated just how massive the effects of such a link were.
The data was collected with the help of CALIPSO over a period of 6 years (from 2007 to 2013). The Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observation is responsible for tracking dust clouds as well as analyzing how airborne particles and clouds travel across the planet.
A recent paper, published in Tuesday’s issue of the Geophysical Research Letters, provides an accurate satellite-based estimation of the quantity of phosphorus that has been transported over the years. Another paper has also addressed this issue, providing a multi-year satellite estimate of the dust quantities being transported from the Saharan Desert to the Amazonian rainforest. CALIPSO concluded that approximately 182 million tons of dust leave the Sahara yearly and while the majority of dust falls into the ocean, there is a large quantity of dust that settles across the basin of the Amazon River. 27,7 million tons to be precise.
And while one may believe that this phosphorus cannot possibly make such a difference considering the vast amounts of nutrients available in the Amazon, the situation isn’t as happy. While many nutrients are locked up inside the plants found in the Amazon and are quickly absorbed back into trees and plants after leaves and other organic matter is decomposed, phosphorus is in extremely limited quantities. Countless floods and rains wash away large quantities of phosphorus in the soil, so that the phosphorus transported by Saharan dust clouds comes as manna from heaven.
Essentially, dust is and will always be a key component of our planet’s system, Hongbin Yu, Maryland University atmospheric scientist said. These dust clouds transport enough quantities of dust towards the Amazon to make up for the phosphorus being washed away by floods and rains, making sure to even out the balance. In the absence of these quantities of dust, Yu says, the Amazon might be in for massive problems in 10 to 100 year’s time.
In conducting their work, Yu and his colleagues decided on tracking the Saharan dust on account of it being the largest on Earth. Additionally, it allows one of the most bio-diverse places on the planet to exist.
Scientists also analyzed the pattern of dust being transported over the years, showing that there was great variability in the pattern. Between the largest amounts of dust being transported in 2007 and the smallest amounts transported in 2011, researchers noticed that there had been an 86 percent change.
In their future work, Yu and his colleagues hope to also include the other types of aerosols to be found in the Amazon (from fire smokes to biological particles, fungi, pollen and spores) so as to understand whether these aerosols have an influence on local clouds and whether they are influenced by Saharan dust.
Image Source: nasa.gov