Scientists have confirmed that microbes can travel thousands of miles across continents by attaching themselves to dust particles.
Professor William Broughton and his colleagues from the University of Geneva, Switzerland, arrived at the conclusion after analyzing dust samples collected by Charles Darwin and other almost 200 years ago.
Geo-chemical analyses showed that these samples contained wind-fractionated dust from West Africa and some travelled as far as the Caribbean. Their results clearly show that diverse microbes, including ascomycetes, and eubacteria can live for centuries and survive intercontinental travel.
Desert storms stir up and deposit 50 million tonnes of dust particles from the Sahara to the Amazon every year. The largest, single source of dust on the planet is the Bodélé Depression in Northern Chad. As surface sand is whipped up into the air, larger particles are continually lost, and only the finest reach the troposphere, where they are blown on trade winds across the Atlantic.
Similar fractionation of microbes also occurs, and only some of those who survive, travel across oceans.
"These findings push forward our understanding of planetary microbial ecology." said Professor Broughton.
Scientists have also pondered upon the fact that whether these microbes traveling across continents spread contaminants and diseases.
"Obviously, intercontinental spread of micro-organisms has been with us for a very long time. So, unless land-use patterns in the Western Sahara have changed recently, disasters like the demise of coral in the Caribbean, cannot be ascribed to the intercontinental travel of desert bugs" said Professor Broughton.