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Wednesday, August 4, 2010

Microorganisms fly around the world

It is well known that microorganisms can travel through the air on dust particles. Until recently, the extent of this migration was not known. An international team of scientists have now identified some of the species involved and the distances they go.

In particular, the scientists examined the microorganisms that travel from the Sahel region (shown here as an orange stripe) and other parts of the Sahara Desert on clouds of dust to other parts of the world. The team, led by Isabel Reche of the University of Granada and Emilio Casamayor from the Blanes Center for Advanced Studies, were able to identify nearly all the species in the dust clouds by using DNA analysis on collected samples.

Samples were collected from high mountain lakes in North America, Europe and Antarctica. Surprisingly, many of the same species were found raining down on the lakes in all locations. In addition, many of the organisms, which include bacteria, funguses and viruses were still viable upon arrival.

The Saharan dust is clearly traveling around the whole world. In fact, the dust coming up from Africa has increased dramatically in recent years due to longstanding drought in the Sahel region, a consequence of climate change. The rain of African dust and microorganisms may change local ecosystems, both by adding fertilizer and by choking native plants and animals. These global dust storms may also be a way of spreading disease.