How Hidden Soil Fungi ‘Steal’ Bacterial DNA to Control the Rain
Tiny organisms on the ground – bacteria and fungi – have a “superpower” that allows them to reach up into the atmosphere and pull down the rain, according to a recent study.
To understand how a microbe can control a storm, we first have to look at how clouds become rain. High up in the atmosphere, water doesn’t always freeze at 0°C. Temperatures are normally much lower at cloud level but pure water can stay liquid down to a bone-chilling -40°C.
Most rain starts as ice. In the atmosphere, clouds are full of “supercooled” water – liquid that is colder than freezing but hasn’t turned to ice yet because it has nothing to hold onto.
For a cloud to turn into rain or snow, it needs a “seed”– a tiny particle for water molecules to grab onto so they can crystallise into ice, then fall from the clouds as rain. Dust, soot and salt – swept into the clouds by wind – can do this, but they aren’t very good at it. They usually require the temperature to drop significantly before they start working. This is where biology enters the frame.