Where does the bacteria come from?

[Crepe]

Just out of curiosity, where exactly does the bacteria in SW systems come from? I know from experience that taking aragonite sand and dumping it in a saltwater tank and seeding with some shrimp WILL end up with a cycled tank. But how would halophilic bacteria even make it into the tank? Are there really spores of such bacteria in the air, nearly 100 miles from the coast? What about for people inland? Or is nitrobacter able to survive in salt AND fresh.

 

[mr_X]

Bacteria - Wikipedia, the free encyclopedia

read the first couple sentences. it's already in the tank, just in tiny amounts. it's on your hands, in your glass, and on that keyboard in front of you, as well as the monitor.
we wash ourselves and surfaces that we want to control it on, but it's not gone.