Featured Research

from universities, journals, and other organizations

Millions of microorganisms reach Spain from the Sahara Desert and the Sahel region -- by flying

Date:
August 10, 2010
Source:
Fundación BBVA
Summary:
Every day, millions of microorganisms reach Spain from the Sahara Desert and the Sahel region -- by flying. Louis Pasteur demonstrated back in 1861 that germs can move through the air, but it was only recently discovered that bacteria, fungi and viruses can travel thousands of kilometers stuck onto dust particles. Satellite images show clouds that come close to the size of the Iberian Peninsula.

A deserted road in a sandstorm runs along the Eastern Sahara Desert between the White Desert and the Black Desert in Egypt. Every day, millions of microorganisms reach Spain from the Sahara Desert and the Sahel region -- by flying.
Credit: iStockphoto/David Ciemny

Every day, millions of microorganisms reach Spain from the Sahara Desert and the Sahel region -- by flying. Louis Pasteur demonstrated back in 1861 that germs can move through the air, but it was only recently discovered that bacteria, fungi and viruses can travel thousands of kilometers stuck onto dust particles. Satellite images show clouds that come close to the size of the Iberian Peninsula.

For the first time, the international team on the Ecosensor project, funded by the BBVA Foundation, has analyzed these traveling microorganisms using molecular biology techniques. As well as identifying the species, they have found that they colonize high-mountain lakes in the Sierra Nevada and the Pyrenees, and that the phenomenon is escalating with climate change.

The "migration" of these microorganisms on African dust is most intense in spring and summer, and has been gathering momentum in recent years; at times multiplying their numbers ten times over. This is due, researchers say, to the drought afflicting the Sahel region for the last thirty years, itself a product of our changing climate. An added spur is the loss of plant cover in Africa driven by changes in farming practices. It is reckoned that between 60 and 200 million tons of dust rise up from the Sahara every year; a material rich in nitrogen, phosphorus and iron with an important role in the growth of marine plankton, and even the fertilization of tropical forests.

Ecosensor brings together an international team of atmospheric physicists and biologists led by Isabel Reche, of the University of Granada, and Emilio O. Casamayor, from the Blanes Center for Advanced Studies. The molecular biology techniques these researchers use allow them to detect almost all the organisms present in a given sample, in contrast to earlier methods which Reche explains revealed "a good deal less than there really is."

The Canary Islands bear the brunt

That is why until now we could not even identify 0.1 percent of the 500 bacteria present in a liter of air, and had no inkling of how they might affect their "destination" ecosystems. The Saharan dust spreads across the whole planet, but the prevailing winds -- from the east -- mean the regions most affected are the Canary Islands and the Caribbean.

Ecosensor researchers have taken air samples in the places where it is easiest to detect the rain of microorganisms, such as high-mountain lakes. "Such spots have barely been altered by local human activity" Reche remarks, " so they are invaluable for studying the incidence of invading airborne microorganisms blown in from remote sources."

The lakes chosen are located in Sierra Nevada and the Pyrenees, as well as the Alps (Austria), Argentinean Patagonia, the Bylot Islands in the Arctic (Canada), and the South Shetland archipelago (Antarctica).

The researchers suck out air, filter it and extract the DNA of the organisms present. "By analyzing the genes we can tell what microorganism they belong to," Reche continues. They also separate the microorganisms to ascertain which can reach the lakes alive.

The same life in Sierra Nevada, the Pyrenees and Mauritania

Their results, which have recently appeared in various scientific publications, show that Sierra Nevada and Pyrenean lakes harbor microorganisms "that we have also found in the soil in Mauritania," says Reche. "It is truly amazing." Among the microorganisms identified are Pseudomonas -- a Bacillus genus capable of colonizing a wide range of niches; Staphylococci -- a genus that includes microorganisms present in human skin, and Acinetobacter, which contribute to the mineralization of the soil. In general terms, they are considered to be non-pathogenic for humans.

But how might the advent of these new microorganisms affect local ecosystems? "The increase in dust load in pristine ecosystems, like high-mountain lakes, has major repercussions" explains Reche, "because with it come nutrients that fertilize the lakes and alter their microbial communities." Some of these changes have harmful effects; indeed the dust may already be damaging the fauna and flora of some ecosystems. Caribbean corals, for instance, are suffering decline due to excess dust deposition.

Another big question is, how do microorganisms manage to stay biologically active after their journey? The dust travels at between 2000 and 4000 meters altitude, exposed to severe dryness and harmful radiation; not all the organisms found form spores, so they must have other defense mechanisms at their command. One hypothesis mentioned by Reche is "an increase in the quantity of protective pigments, which adhere to the mineral particles, conferring a degree of protection."


Story Source:

The above story is based on materials provided by Fundación BBVA. Note: Materials may be edited for content and length.


Cite This Page:

Fundación BBVA. "Millions of microorganisms reach Spain from the Sahara Desert and the Sahel region -- by flying." ScienceDaily. ScienceDaily, 10 August 2010. <www.sciencedaily.com/releases/2010/07/100726094751.htm>.
Fundación BBVA. (2010, August 10). Millions of microorganisms reach Spain from the Sahara Desert and the Sahel region -- by flying. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2010/07/100726094751.htm
Fundación BBVA. "Millions of microorganisms reach Spain from the Sahara Desert and the Sahel region -- by flying." ScienceDaily. www.sciencedaily.com/releases/2010/07/100726094751.htm (accessed October 22, 2014).

Share This



More Plants & Animals News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Cadaver Dogs Aid Search for More Victims of Suspected Indiana Serial Killer

Cadaver Dogs Aid Search for More Victims of Suspected Indiana Serial Killer

Reuters - US Online Video (Oct. 21, 2014) — Police in Gary, Indiana are using cadaver dogs to search for more victims after a suspected serial killer confessed to killing at least seven women. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
White Lion Cubs Unveiled to the Public

White Lion Cubs Unveiled to the Public

Reuters - Light News Video Online (Oct. 21, 2014) — Visitors to Belgrade zoo meet a pair of three-week-old lion cubs for the first time. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) — Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
Powered by NewsLook.com
White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) — Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins