Editing Amazon rainforest (section)

====Sahara Desert dust windblown to the Amazon====
More than 56% of the dust fertilizing the Amazon rainforest comes from the [[Bodélé depression]] in Northern Chad in the [[Sahara]] desert. The dust contains [[phosphorus]], important for plant growth. The yearly Sahara dust replaces the equivalent amount of phosphorus washed away yearly in Amazon soil from rains and floods.<ref>{{cite journal|doi=10.1002/2015GL063040 | volume=42 | issue=6 | title=The fertilizing role of African dust in the Amazon rainforest: A first multiyear assessment based on data from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations | year=2015 | journal=Geophysical Research Letters | pages=1984–1991 | last1 = Yu | first1 = Hongbin| bibcode=2015GeoRL..42.1984Y | doi-access=free }}</ref>

NASA's [[CALIPSO]] satellite has measured the amount of dust transported by wind from the Sahara to the Amazon: an average of 182 million tons of dust are windblown out of the Sahara each year (some dust falls into the Atlantic), 15% of which of falls over the Amazon basin (22&nbsp;million tons of it consisting of phosphorus).<ref>{{cite web|url=http://www.nasa.gov/content/goddard/nasa-satellite-reveals-how-much-saharan-dust-feeds-amazon-s-plants|title=Saharan Dust Feeds Amazon's Plants|first=Rob|last=Garner|date=February 24, 2015|website=NASA|access-date=June 20, 2019|archive-date=June 23, 2019|archive-url=https://web.archive.org/web/20190623142203/https://www.nasa.gov/content/goddard/nasa-satellite-reveals-how-much-saharan-dust-feeds-amazon-s-plants/|url-status=live}}</ref>

CALIPSO uses a laser range finder to scan the Earth's atmosphere for the vertical distribution of dust and other aerosols. and regularly tracks the Sahara-Amazon dust plume. CALIPSO has measured variations in the dust amounts transported – an 86 percent drop between the highest amount of dust transported in 2007 and the lowest in 2011. This is possibly caused by rainfall variations in the [[Sahel]], a strip of semi-arid land on the southern border of the Sahara.<ref>{{cite web|url=https://science.nasa.gov/science-news/science-at-nasa/2015/29apr_amazondust/|title=Desert Dust Feeds Amazon Forests – NASA Science|work=nasa.gov|access-date=July 12, 2017|archive-date=May 14, 2017|archive-url=https://web.archive.org/web/20170514192932/https://science.nasa.gov/science-news/science-at-nasa/2015/29apr_amazondust|url-status=live}}</ref>

Amazon phosphorus also comes as smoke due to biomass burning in Africa.<ref>{{cite journal|last1=Barkley|first1=Anne E.|last2=Prospero|first2=Joseph M.|last3=Mahowald|first3=Natalie|author-link3=Natalie Mahowald|last4=Hamilton|first4=Douglas S.|last5=Popendorf|first5=Kimberly J.|last6=Oehlert|first6=Amanda M.|last7=Pourmand|first7=Ali|last8=Gatineau|first8=Alexandre|last9=Panechou-Pulcherie|first9=Kathy|last10=Blackwelder|first10=Patricia|last11=Gaston|first11=Cassandra J.|date=August 13, 2019|title=African biomass burning is a substantial source of phosphorus deposition to the Amazon, Tropical Atlantic Ocean, and Southern Ocean|url=|journal=Proceedings of the National Academy of Sciences|volume=116|issue=33|pages=16216–16221|bibcode=2019PNAS..11616216B|doi=10.1073/pnas.1906091116|pmc=6697889|pmid=31358622|doi-access=free}}</ref><ref>{{cite web |title=Smoke from Africa fertilizes the Amazon and tropical ocean regions with soluble phosphorous [''sic'']|url=https://phys.org/news/2019-08-africa-fertilizes-amazon-tropical-ocean.html |website=phys.org |language=en-us |access-date=August 14, 2019 |archive-date=August 14, 2019 |archive-url=https://web.archive.org/web/20190814181214/https://phys.org/news/2019-08-africa-fertilizes-amazon-tropical-ocean.html |url-status=live }}</ref>