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  • The Mariana Trench is the deepest point on Earth.

  • So deep that if you dropped Mount Everest inside,

  • its peak would still be more than

  • a kilometer underwater.

  • So deep that no light reaches the bottom.

  • And if you could feel it, the pressure would be

  • about equal to the weight of

  • 48 jumbo jets.

  • Yet, somehow, life finds a way.

  • Very weird life.

  • The truth is, at first glance...

  • Douglas Bartlett: You wouldn't be very impressed.

  • It's gonna be this

  • kind of silky, gray-green sediment.

  • Narrator: But if you put out some food,

  • some of the planet's strangest creatures

  • would emerge from the darkness.

  • Like these.

  • They're crustaceans called amphipods.

  • And some individuals can grow

  • up to 30 centimeters long,

  • or about the size of an American football.

  • Now, like lobsters,

  • these animals have hard exoskeletons

  • made of calcium carbonate,

  • which you normally wouldn't find down here,

  • more than 10,000 meters down.

  • Because once you pass 4,500 meters or so,

  • the pressure is so great

  • and the temperature is so low

  • that calcium carbonate dissolves.

  • But these amphipods have a secret weapon.

  • Or rather, shield.

  • The crustaceans are covered

  • with an armor made of aluminum,

  • which they synthesize in their bodies,

  • using aluminum found in the seafloor.

  • It's a good thing, too,

  • because those shells are their best defense

  • against something else lurking in the abyss.

  • The Mariana snailfish,

  • aka the deepest fish ever discovered,

  • which scientists have seen

  • more than 8,000 meters down.

  • And there are a lot

  • of strange things about these fish.

  • They have flexible bones,

  • which scientists think helps them withstand pressure.

  • They're blind, because, well, when it's that dark,

  • there's no point in seeing.

  • And...

  • Bartlett: Their skin is translucent,

  • so you can see their internal organs.

  • Narrator: But they're also one of the trench's

  • top predators.

  • And if you want proof,

  • check out this terrifying X-ray image.

  • Now, snailfish are certainly odd.

  • But then again, you haven't yet met...

  • Bartlett: A xenophyophore.

  • Narrator: It's a single-celled organism

  • akin to a giant amoeba.

  • In fact, at about 10 centimeters long,

  • it's one of the largest

  • single-celled organisms on Earth.

  • The trench also has what Bartlett calls...

  • Bartlett: These little sea pigs.

  • Narrator: They're small, transparent sea cucumbers

  • that crawl along the ocean floor

  • on tentacle-like legs.

  • But perhaps the most surprising thing you'll discover

  • inside the Mariana Trench is this:

  • Plastic.

  • In 1998, a remotely operated submersible

  • detected a plastic bag

  • at 10,898 meters.

  • And in 2019, an explorer reported

  • signs of plastic debris even further down.

  • What's more, researchers have found microplastics

  • inside the stomachs of amphipods

  • in the Challenger Deep.

  • They called it "the deepest record

  • of microplastic ingestion."

  • And all that goes to show that even here,

  • in the most remote place on the planet,

  • where only four people have ever visited,

  • there are signs of our vast impact on the world.

The Mariana Trench is the deepest point on Earth.

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マリアナ海溝の中身は? (What's Inside The Mariana Trench?)

  • 65 1
    Victoria に公開 2021 年 01 月 14 日
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