The Global Transport of Dust

dirt is carried aloft. Drifting with the sus pended dust particles are soil pollutants such as herbicides and pesticides and a significant number of microorganisms? bacteria, viruses and fungi. We can gain some appreciation of how much micro bial life is actually floating in our atmos phere by perfonning a quick calculation. There are typically about one million bacteria per gram of soil, but lef s be con servative and suppose there are only 10,000 bacteria per gram of airborne sed iment. Assuming a modest one billion metric tons of sediment in the atmos phere, these numbers translate into a quintillion (1018) sediment-borne bacte ria moving around the planet each year?enough to form a microbial bridge between Earth and Jupiter.