字幕列表 影片播放 列印英文字幕 [MUSIC Drop a plastic bottle in the recycling bin, and it might one day become something totally new. But the stuff we drop in the toilet? We don't think about number two becoming anything. But all over nature, the waste of other animals re-enters the great circle of life. Here's how poop shapes the world we live in. [MUSIC] Viewed up close, corals are tiny tentacled animals. But those living polyps sit on mountains of coral skeletons made of calcium carbonate. When parrotfish eat coral, the bony bits they can't digest make their way back to the sea floor. In other words? Parrotfish poop sand made from coral. We're talking one metric ton, per fish, per year. Enough to make up a big part of some of our favorite beaches. Near the ocean's surface, marine algae absorb sunlight and carbon dioxide to make energy and oxygen. But like terrestrial plants, they need nutrients like nitrogen and iron to get the job done. Giants like whales and whale sharks answer nature's call in a big way, pumping out more than 50,000 liters of nutrient-rich waste in a single go. Clouds of whale poop carry 10 million times more iron than seawater, so where whales “go” phytoplankton thrive. And when those plankton die, the carbon stored in their bodies piles up on the ocean floor, eventually becoming things like shale and oil. Phytoplankton are so small that billions can fit in a bucket of seawater. But altogether, they absorb millions of tons of carbon from the atmosphere and give off over half of the oxygen we breathe. Much of the ocean's other waste falls to the deep sea in clouds called marine snow where it feeds animals like the vampire squid. But the poop elevator doesn't stop at the basement. Deep divers like sperm whales hunt squid near the sea floor, then return to the surface to breathe… and poop, recycling nutrients from the abyss and starting the whole cycle over. Ocean poop won't cure climate change, but without enough recycled nutrients, dying plankton can disrupt the whole ocean ecosystem. One plankton die-off during the Cretaceous period may have had a hand in oceans losing their oxygen about 94 million years ago, causing a mass extinction that lasted five hundred thousand years. Poop can even move nutrients from the ocean, onshore. Birds that feed on fish airdrop fecal fertilizer when they fly back over land. Ancient reptiles like dinosaurs and pterosaurs would have done the same thing. Enriched soil allowed plants to flourish like never before, and their seeds were spread far and wide by the “movements” of monstrous fruit-eating mammals. Without those prehistoric poopers, the scat-egories of lifeforms we see today may have looked very different. Some plants still struggle since the animals that used to carry off their seeds are now extinct. Passing an avocado pit is pretty painful if you're not a giant ground sloth, which you can hear more about in this video. Plenty of modern animals are still carrying the load, though. After clearcutting rainforests, fruit-eating bats and birds can act like flying Johnny Appleseeds. Where they poop is where new rainforests grow. Down in the soil, a typical earthworm population recycles around two tons of organic matter per acre every year. All this waste keeps terrestrial ecosystems healthy from top to bottom. So from the forests to the oceans, we know our planet's lungs breathe easier thanks to poop. And that means we do too! Stay curious.