Using high-resolution imaging,
researchers from MIT's Department of Mechanical Engineering observed the effect
of raindrops falling on dry soil laden with bacteria. When falling at speeds
mimicking those of a light rain, at temperatures similar to those in tropical
regions, the drops released a spray of mist, or aerosols. Each aerosol carried
up to several thousand bacteria from the soil. The researchers found the
bacteria remained alive for more than an hour afterward.
If this airborne bacteria were lofted
further by wind, it could travel a good distance before settling back on the
ground to colonize a new location. The researchers estimated that the total
number of bacteria dispersed by raindrops can range from 10,000 trillion to
800,000 trillion cells per year. As a result, global precipitation may
contribute to releasing 1.6 to 25 percent of the total amount of bacteria from
land.
See:
Posted by Dr. Tim Sandle