Saharan dust reaching Amazon quantified
UM Rosenstiel School-led study has important implications for soil
fertility in Amazon Basin

Date:
September 17, 2020
Source:
University of Miami Rosenstiel School of Marine & Atmospheric
Science
Summary:
A new study quantified the amount of Saharan dust reaching the
Amazon to better understand how dust could impact soil fertility
in the region.

Intense tropical weathering and local biomass burning have both
contributed to nutrient-poor soil in the Amazon Basin.



FULL STORY ==========================================================================
A new study by researchers at the University of Miami (UM) Rosenstiel
School of Marine and Atmospheric Science and ATMO Guyane quantified the
amount of Saharan dust reaching the Amazon to better understand how dust
could impact soil fertility in the region. Intense tropical weathering
and local biomass burning have both contributed to nutrient-poor soil
in the Amazon Basin.


==========================================================================
The research team analyzed 15 years of daily measurements of African dust transported in trade winds and collected at a coastal research station
in Cayenne, French Guiana. The results showed that significant quantities
of dust reach the heart of the Amazon Basin and are deposited there.

"African dust provides an important source of nutrients to enhance
Amazonian soil fertility," said Joseph Prospero, professor emeritus at
the UM Rosenstiel School and lead author of the study.

Every year, mineral-rich dust from North Africa's Sahara Desert is lifted
into the atmosphere by winds and carried on a 5,000-mile journey across
the North Atlantic to the Americas. African dust contains phosphorus
and other important plant nutrients that help offset soil losses and
increase Amazonian soil fertility.

This study, the first to quantify African dust transport to South America, showed that significant amounts of dust is deposited to the Amazon. The analysis also found that previous studies, which were based on limited measurements of dust, may have greatly overestimated the impact.

The Amazon Basin plays a major role in global climate. Trees and plants in
the Amazon remove huge quantities of carbon dioxide from the atmosphere
and store the carbon in vegetation. This removal offsets some of the
human-made CO2 emitted into the atmosphere and mitigates the impact of
CO2 on global climate.

The scientists also found that quantities of dust transported to South
America are inversely linked to rainfall in North Africa and concluded
that climate change will affect dust transport to South America.

"Changes in dust transport could affect plant growth in the Amazon
and the amount of CO2 drawn from the atmosphere. This, in turn, would
further impact climate," said Prospero. "Our results highlight the need
for long-term monitoring to identify changes that might occur to Africa
dust transport from climate change."

========================================================================== Story Source: Materials provided by University_of_Miami_Rosenstiel_School_of_Marine_&
Atmospheric_Science. Original written by Diana Udel. Note: Content may
be edited for style and length.


========================================================================== Journal Reference:
1. Joseph M. Prospero, Anne E. Barkley, Cassandra J. Gaston, Alexandre
Gatineau, Arthur Campos y Sansano, Kathy Panechou. Characterizing
and quantifying African dust transport and deposition to South
America: Implications for the phosphorus budget in the Amazon
Basin. Global Biogeochemical Cycles, 2020; DOI: 10.1029/2020GB006536 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200917105358.htm

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