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, funguses 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, have 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, phosphorous 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".
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|Contact: Silvia Churruca|