"What's at the bottom of the bottom of the food chain? Well, think small ... smaller than you can see."

"Microbes in the ocean!"

"There are (and scientists have done the math) trillions of microorganisms in the ocean: plankton, bacteria, krill (they're maybe bigger than 'micro,' but not by much), viruses, protists and archaea (they're like bacteria, but they aren't bacteria)."

"The Earth as we know it wouldn't exist without the trillions of microorganisms that live in the oceans. They're food for most everything that floats or swims, and they make oxygen that we need to breathe."