Apparently they have Airborne.

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Bacteria in the atmosphere play a role in making it rain and hail.

And to summarize some of the recent "discoveries" I've read about what bacteria does, beside interacting with plants and soil in all sorts of symbiotic, essential and productive ways, eating our oil spills in the ocean, working in and on our bodies with our immune systems, may be used to help cure alzheimer's, are essential for digestion , the bacteria in our gut communicates with our brains to influence our levels of happiness and depression. (Apparently you're only as happy as your gut bacteria tells you to be. lol)

Soil, water, air, in geysers, deep ocean vents, in asteroids, inside us, on us, outside of us.... All in all, if those little suckers ever decide to form a "bacteria-net" and start running the show, Arnold isn't going to stand a chance of saving us.

Which reminds me, have I posted the little factoid I heard the other day: if an alien scooped one of us up and took us back to his space ship and extracted all the DNA on and in a human, 98% of it is bacterial, not human?