Volcanic ash can ground planes and, in severe eruptions, it can enter the lungs - but what about the microbe world?
Microorganisms don't fly planes or have lungs, but surely this type of natural disaster must effect them in some way?
A volcanic eruption ash cloud consists mainly of fine rock and glass particles that are quickly expelled into the atmosphere. The ash is then blown via wind systems, and can travel hundreds of miles, until it eventually falls to the ground.
Immediately after the volcanic ash is spewed from the volcano it would be highly doubtful that any bacteria would be able to survive (due to the ash particles being very hot). However, when the ash falls to earth and into the soil it enables the soil to retain more water, thus creating conditions desireable for soil dwelling bacteria to grow. These bacteria replenish the soil's nutrients and therefore make the soil more fertile, with plants and crops benefiting.
However, a few skincare websites that sell volcanic ash/clay state it has antibacterial properties due to it being high in sulphur. This is true due to sulphur having antibacterial properties, however this does not mean grab some volcanic ash from your car windscreen and smear it over yourself - due to only small amounts of ash present it's likely to have little or no effect.
Thanks for reading!
References - http://www.telegraph.co.uk/gardening/7611038/Volcano-ash-could-be-good-for-gardens.html
Kurt Gödel's Open World
10 hours ago in The Curious Wavefunction