Poop is a gross—yet essential—part of the circle of life. Plus, without it, we may not have gloriously sandy beaches, a healthy ocean, thriving terrestrial ecosystems, or even fruits like avocados. Confused as to how this icky waste benefits the wider world? Joe Hanson, host of It’s OK To Be Smart, explains in the video below. For example, parrot fish eat coral, which are tiny, living polyps atop mountains of coral skeletons. The fish can’t digest the bony parts, so they poop it out. The final product is sand—as much as 2200 pounds per fish per year. (So yes, when you're lounging on the beach, you may be sitting on fish poop.) Meanwhile, giant marine animals like whales and whale sharks also poop, but their bowels blast out more than 13,000 gallons of nutrient- and iron-rich waste per pooping session. In turn, this excrement nourishes plankton, allowing them to produce more than half the oxygen we breathe and absorb millions of tons of carbon from the atmosphere. Curious to learn more about how the stinky stuff makes the world go 'round? Watch the full video below.