. The Amazon rainforest is densely green and humid forest that gets millions of tons each year of Saharan dust. This dust is rich in vital nutrients such as phosphorus, which helps replenish the soil of the Amazon. The first estimate of how much phosphorus gets swept over the Atlantic Ocean from Africa to South America by scientists, published in Geophysical Research Letters. They estimated that annually about 22,000 tons of just phosphorus makes the journey each year, which is approximately the same amount the rainforest loses from rain and flooding. Conceptual image showing dust from the Sahara Desert traversing the Atlantic Ocean and reaching the Amazon rainforest. Credit: Conceptual Image Lab NASA/Goddard Space Flight Center. 0. 08% refers to phosphorous. This study forms part of larger research that aims to understand the impact of dust on the environment, and how it affects local and global climate. Climate and dust interact. Dr. Hongbin Yu is an associate researcher at the Earth System Science Interdisciplinary Center. This joint center of NASA’s Goddard Space Flight Center and the University of Maryland, stated that “We know that dust plays a vital role in many aspects. Dust is an integral part of the Earth’s system. “Durch will impact climate, and at the same, climate change may affect dust.” Scientists were particularly interested in dust collected from Bodele Depression, Chad. This ancient lakebed is rich in dead microorganisms, which in turn affects the Earth’s climate. The soils of Amazonia lacks phosphorus, as well as other essential nutrients, which are washed away in the heavy, frequent rains. The Amazon ecosystem is one of most rich and wet in the world. It relies heavily on dust from Sahara, which is one of our driest areas. Dr. Yu and his colleagues analyzed and gathered data from NASA’s Cloud Aerosol Lidar (CALIPSO), satellite between 2007, and 2013.. Because it’s the largest transport of dust, they focused on Saharan Dust that was transported over the Atlantic to South America and into the Caribbean Sea. They used samples taken from the Bodele Depression as well as ground stations in Barbados, Miami and Barbados to estimate how much phosphorus there was in Saharan Dust. This estimate was then used to calculate how much phosphorus had been deposited within the Amazon basin. They pointed out that only seven years of data are not sufficient to draw conclusions about long-term trends. It is an important step towards understanding the behavior of dust and other particles in winds as they travel across the ocean. Chip Trepte (CalipsO project scientist at NASA Langley Research Center), said that the pattern changes significantly year to year. The difference in the amount of dust transport between 2007 & 2011 is what was called . These variations are due to the Sahel conditions, Dr. Yu believes. Sahel refers to the strip of semi-arid, long land at the Sahara’s southern boundary. The years of frequent and heavy rainfalls in the Sahel are usually followed by a decrease in dust transport across the ocean the year after. Researchers aren’t sure how this happens. Some theories are being considered. A higher rainfall level could lead to more vegetation, and therefore less soil susceptible to wind erosion in Sahel. There is also the possibility that rain could be linked to wind circulation patterns, which sweep dust out of the Sahara and Sahel to the upper atmosphere. This is where it travels long distances to South America. Dr. Yu stated that this is a small universe and all of us are connected. Citation: “The Fertilizing role of African Dust In the Amazon Rainforest” Hongbin Yu and Mian Chin. Tianle Yuan, Huisheng Bian. Lorraine A. Remer. Joseph M. Prospero. Ali Omar. David Winker. Yuekui Yan, Yan Zhang. Zhibo Zhang. Chun Zhao. Geophysical Research Letters. DOI: 10.1002/2015GL063040. NASA Goddard Video: Saharan Dust to Amazon 3D
