mongabay.com logo About  |   Contact  |  Mongabay on Facebook  |  Mongabay on Twitter  |  Free newsletter  
Rainforests | Tropical fish | Environmental news | Mongabay-Indonesia | For kids | Madagascar | Photos | Non-English languages | Tropical Conservation Science
print


An undamaged Amazon produces its own clouds and rain

Jeremy Hance
mongabay.com
September 21, 2010



Researchers recently traveled to the remote Brazilian Amazon to investigate how clouds are formed and rain falls in an atmosphere unburdened by human-caused pollution. Studying the atmospheric aerosol particles, which impact cloud formation and particles, above a pristine forests, researchers discovered that when left alone the Amazon acts as its own 'bioreactor': clouds and precipitation are produced by the abundance of plant materials.

"The trees basically 'sweat out' organic molecules that react with compounds in the atmosphere, producing tiny particles that are around 20 to 200 nanometers in size," explains Markus Petters, an assistant professor at North Carolina State University and one of the members of the study, in a press release. "These particles seed the clouds. In addition, other biological particles form the ice nuclei for the clouds." Such ice nuclei are essential for the formation of precipitation.


Clouds forming over the Amazon rainforest in Colombia. Photo by: Rhett A. Butler.
In other words, in a pristine rainforest clouds and precipitation are both instigated by organic materials from the forest such as plant debris, pollen, fungal spores, and bacteria. According to the study 80 percent of supermicron particles—with a diameter greater than a micrometer—in the atmosphere were produced by the Amazonian life. These supermicron particles form the ice nuclei, which eventually lead to precipitation. Therefore the scientists say that the abundant life of the Amazon essentially creates the clouds and precipitation that sustains it.

"The Brazilian rainforest during the rainy season can be described as a bioreactor", says Ulrich Pöschl of the Max Planck Institute for Chemistry, adding that "we are already able to say that the number of cloud droplets over the Amazon rainforest is aerosol-limited, which means that it depends on the number of aerosol particles which is released by the ecosystem."

If the ecosystem is lost, so are the aerosol particles needed to form clouds and produce precipitation. Petters says that he hopes the study will help scientists worldwide better understand how human activities are changing the world's climate.

"The Amazon is unique in that it provides a good place for us to observe atmospheric interactions without human influence, and to catalog baseline activity for the rainforest," he explains. "If we understand that baseline well enough around the world, we can run simulations that show how human aerosol emissions modulate climate change."

The Amazon rainforest is the world's largest, yet it faces myriad threats from commercial agriculture, cattle ranching, logging, oil and gas, dams, road construction, and slash-and-burn farming. From 1970-2005, the Amazon has been reduced by 600,000 square kilometers (232,000 square miles) in Brazil, an area the size of Ukraine and nearly 20 percent of Brazil's total rainforest.



Citation: U. Pöschl, S. T. Martin, B. Sinha, Q. Chen, S. S. Gunthe, J. A. Huffman, S. Borrmann, D. K. Farmer, R. M. Garland, G. Helas, J. L. Jimenez, S. M. King, A. Manzi, E. Mikhailov, T. Pauliquevis, M. D. Petters, A. J. Prenni, P. Roldin, D. Rose, J. Schneider, H. Su, S. R. Zorn, P. Artaxo, M. O. Andreae. Rainforest Aerosols as Biogenic Nuclei of Clouds and Precipitation in the Amazon. Science 17 September 2010: Vol. 329. no. 5998, pp. 1513-1516. DOI: 10.1126/science.1191056







Related articles

Healthy coral reefs produce clouds and precipitation

(03/03/2010) Twenty years of research has led Dr. Graham Jones of Australia's Southern Cross University to discover a startling connection between coral reefs and coastal precipitation. According to Jones, a substance produced by thriving coral reefs seed clouds leading to precipitation in a long-standing natural process that is coming under threat due to climate change.


Air pollution in China reduces rainfall

(08/31/2009) Air pollution in eastern China over the past half century has reduced rainfall and exacerbated the risk of drought and crop failures, reports a study published in the Journal of Geophysical Research.


Massive deforestation in the past decreased rainfall in Asia

(06/25/2009) Between 1700 and 1850 forest cover in India and China plummeted, falling from 40-50 percent of land area to 5-10 percent. Forests were cut for agricultural use across Southeast Asia to feed a growing population, but the changes from forests to crops had unforeseen consequences. A new study published in the Proceedings of the National Academy of Sciences links this deforestation across Southeast Asia with changes in the Asian Monsoon, including significantly decreased rainfall.









CITATION:
Jeremy Hance
mongabay.com (September 21, 2010).

An undamaged Amazon produces its own clouds and rain .

http://news.mongabay.com/2010/0921-hance_amazon_rain.html


Tags:
amazon weather climate change climate science rainforests jeremy hance green environment brazil south america latin america rainforest precipitation Amazon rainforest ecological services ecosystem services environmental services forests tropical forests

print



Environmental news index | RSS | News Feed | Twitter | Home


Advertisements:



T-shirts, shopping bags, calendars, and more.




DON'T LIKE ADS? Become a mongabay supporter


WEEKLY NEWSLETTER
Email:


RECENT FEATURES
Looking for a yetiLooking for a yeti? Use leeches
Cinderella animalsCinderella animals
Uncontacted tribes spotted in ColombiaUncontacted tribes spotted in Colombia
17 celebrated scientists on how to make a better world17 celebrated scientists on how to make a better world


POPULAR PAGES
Rainforests
Rain forests
Amazon deforestation
Deforestation
Deforestation stats
Why rainforests matter
Saving rainforests
Amazon rainforest
Congo rainforest
Deforestation data
Rainforest canopy

Special sections
New Guinea
Finding new species
Sulawesi
Madagascar
Borneo
REDD

News
Most popular articles
Worth saving?
Forest conservation
Cell phones in Africa
Seniors helping Africa
Saving orangutans in Borneo
Palm oil
Amazon palm oil
Future of the Amazon
Cane toads
Dubai environment
Investing to save rainforests
Visiting the rainforest
Biomimicry
Defaunation
Blue lizard
Extinction debate
Extinction crisis
Industrial deforestation
Save the Amazon
Rainforests & REDD
Brazil's Amazon plan
Avatar story
Amazon ranching

News topics
Amazon
Biofuels
Brazil
Carbon Finance
Conservation
Climate Change
Deforestation
Energy
Happy-upbeat
Indonesia
Interviews
Oceans
Palm oil
Rainforests
Wildlife
MORE TOPICS



Non-English Sites
Chinese
French
German
Indonesian
Italian
Portuguese
Spanish
Other languages

Nature Blog Network







Photos
Brazil photos
Brazil

China photos
China

Colombia photos
Colombia

Costa Rica photos
Costa Rica

Deforestation photos
Deforestation

Gabon photos
Gabon

India photos
India

Indonesia photos
Indonesia

Kenya photos
Kenya

Madagascar photos
Madagascar

Peru photos
Peru

Peru photos
Rainforest



ABOUT
Mongabay.com seeks to raise interest in and appreciation of wild lands and wildlife, while examining the impact of emerging trends in climate, technology, economics, and finance on conservation and development (more)

Help support mongabay.com when you buy from Amazon.com


BOOKS BY MONGABAY AUTHORS
Rainforest book for kids Conservation in an age of mass extinction


FREE WEEKLY NEWSLETTER



HIGH RESOLUTION PHOTOS / PRINTS








Copyright mongabay 2010

Carbon dioxide (CO2) emissions generated from mongabay.com operations (server, data transfer, travel) are mitigated through an association with Anthrotect,
an organization working with Afro-indigenous and Embera communities to protect forests in Colombia's Darien region.
Anthrotect is protecting the habitat of mongabay's mascot: the scale-crested pygmy tyrant.