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  • [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 whalesgo

  • 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 breatheand 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 themovementsof 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.



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B2 中高級 美國腔

大便如何塑造世界 (How Poop Shapes the World)

  • 114 4
    Flora Hu 發佈於 2021 年 01 月 14 日