New research revealed just how much dust from the Sahara desert is transported to the Amazon rainforest every year.
Every year millions of tons on nutrient-rich Saharan dust travel across the Atlantic Ocean from northern Africa to the humid rainforests of South America, the University of Maryland reported. These findings are the first to estimate exactly how much phosphorous is transported to the Amazon in this dust. The phenomenon is the largest transport of dust seen on this planet.
The findings show about 22,000 tons of phosphorous is carried the Amazon from the Sahara desert every year, which is about the same amount that the rainforest loses from events such as rain and flooding. The transported Saharan phosphorous accounts for only 0.08 percent of the 27.7 million tons that settle in the desert every year.
"We know that dust is very important in many ways. It is an essential component of Earth system. Dust will affect climate and, at the same time, climate change will affect dust," said lead author Hongbin Yu, an associate research scientist at the Earth System Science Interdisciplinary Center (ESSIC), a joint center of the University of Maryland and NASA's Goddard Space Flight Center.
The researchers made their findings by looking at data collected from NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite between 2007 and 2013. They also estimated the phosphorus content of Saharan dust Bodélé Depression and ground stations across the region. The seven-year data record looked at in the study was not enough to uncover long-term trends, the findings could provide insight into how dust particles and aerosols behave as they are transported across the ocean.
"We need a record of measurements to understand whether or not there is a fairly robust, fairly consistent pattern to this aerosol transport," said Chip Trepte, project scientist for CALIPSO at NASA's Langley Research Center, who was not involved in the study.
The findings showed a varied pattern of aerosol transport over the years, most likely tied to conditions on the strip of semi-arid land on the desert's southern border, dubbed the Sahel. Years that saw heavy rainfall in the Sahel tended to be accompanied by lower levels of dust transport.
The findings were published in a recent edition of the journal Geophysical Research Letters.
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