Clouds Provide Atmospheric Oases for Microbes

When thermodynamic conditions prove favorable in the atmosphere, water vapor condenses on aerosol particle surfaces, forming micrometer-sized droplets or ice crystals constituting clouds. Even though clouds gather only 0.03% of the fresh water on Earth, they are important components of climate, acting as filters to solar and infrared radiation entering and leaving the planet. Moreover, they provide a multiphasic mixture of liquid, solid, and gas to support chemical reactions affecting the composition of the atmosphere.