In Northern Nevada’s Great Boiling Spring, strange microscopic creatures thrive in water hot enough to kill you.

Parasitic bacteria that are entirely dependent on the other bacteria they infect have been discovered for the first time, in human spit. The tiny cells have gone undetected for decades, but appear to be linked to gum disease, cystic fibrosis and antimicrobial resistance.

Although global microbial populations are orders of magnitude larger than nearly any other population in, on or around the planet, only a fraction has been identified thus far.

We spend much of our lives trying to avoid bacteria — washing our hands, squirting hand sanitizer and taking courses of antibiotics. But what about the countless bacteria that live within us every day?

The mysterious and diverse world of bacteria just got its very own expansion pack. A total of 35 new groups, or phyla, of bacteria have been discovered in groundwater in Rifle, Colorado. The finding will likely add a bunch of new species to the tree of life — species that are quite different from other bacteria, scientists note. But here's what's really remarkable: the number of new bacterial groups is almost the same as the number of known animal phyla on Earth. We were always outnumbered, but you still might want to let the magnitude of this discovery sink in.

“We really are more than human. They’re on us; they’re in us; they’re everywhere.” My body, Brian Hedlund casually tells me, has 10 times more microbial cells than human, around 100 trillion. So much for hand sanitizer.