To learn more, go to Brilliant.org/SciShow.

前往 Brilliant.org/SciShow 了解更多資訊。

I don't know if you've noticed, but animals kind of need oxygen.

我不知道你有沒有注意到，但動物都需要氧氣。

That's because animals generally get their energy from cellular structures called mitochondria,

這是因為動物通常在粒線體中獲得能量，

and those processes require oxygen to work.

而那些過程需要氧氣才能運作。

So if somebody stole all of the Earth's O2, things would end pretty quickly around here.

因此，如果有人偷走地球上所有的氧氣，一切很快就會在此結束。

Except, as it turns out, there are at least some animals that would be perfectly fine.

其實，至少有些動物還是過得很好。

Because in 2010, scientists published a paper announcing

因為在 2010 年，科學家發表了一篇論文，其表示

that they'd found three species of them that straight-up don't need oxygen!

他們發現三種完全不需要氧氣的物種！

Now, to be clear, not all life needs oxygen.

明確來說，不是所有生命都需要氧氣。

There are plenty of single-celled microbes that are anaerobic,

有很多單細胞微生物是厭氧性的，

meaning they can survive just fine without the stuff.

代表它們不用氧氣也能過得很好。

Instead of oxygen, these organisms can use other molecules like sulfate or nitrate.

與其利用氧氣，這些生物可以利用其他分子，如硫酸鹽或硝酸鹽。

But for years, scientists thought a system like that wouldn't work for animals,

但長年下來，科學家認為這種系統不適用於動物上，

since their complex, multicellular bodies have higher energy requirements.

因為它們的身體複雜、細胞又多，有更高的能量需求。

Instead, they thought animals needed the more efficient energy production that takes place in mitochondria.

相反的是，他們認為動物在粒線體生產能量時，需要更有效率的方式。

And then came that 2010 paper.

回到 2010 年的那份論文。

This discovery happened in the L'Atalante basin,

此發現在阿塔蘭特盆地，

three thousand meters below the surface of the Mediterranean Sea.

地中海海面三千公尺以下。

L'Atalante is a deep hypersaline anoxic basin,

阿塔蘭特盆地是深層高鹽無氧盆地，

meaning it's super salty and completely devoid of oxygen.

意思就是它超鹹，而且完全沒有氧氣。

It's the kind of place you wouldn't expect to find animals.

這種地方你不會認為有動物。

And indeed, when a research team visited three times between 1998 and 2008,

確實，研究團隊在 1998 年至 2008 年間進行 3 次調查，

that's generally what they saw.

那也是他們所看到。

They did find a lot of single-celled organisms living in the basin,

他們確實發現很多單細胞生物生活在盆地中，

but most of the animals they saw were dead,

但看到的大多數動物都死了，

the result of a so-called “rain of cadavers” from oxygenated waters above.

因為上方含氧水導致出所謂的「屍體雨」。

Most of the animals, but not all of them.

是大部分動物，但不是所有。

Because the team also found an unusually high abundance of tiny, sediment-dwelling animals

因為研究小組還發現異常豐富、微小的動物住在沉積物裡

called loriciferans, and they were seemingly very alive.

叫做鎧甲動物門，它們似乎還活得好好的。

Loriciferans are pretty weird creatures to begin with.

首先，鎧甲動物門是非常怪異的動物。

Their heads are covered in spines, and their bodies are typically encased in a vase-like shell called a lorica.

它們的頭上長滿了棘，身體通常被種皮包覆著，其為花瓶狀的外殼。

But finding them in an oxygen-free basin was a whole new level of weird.

但是在無氧盆地中找到它們，卻是全新奇異的層次。

The researchers observed that the loriciferans were still taking up nutrients,

研究員觀察到，鎧甲動物門仍在吸收營養，

and that some had recently molted.

有的最近還脫皮。

Some even had developing offspring inside them.

有的甚至在體內生出後代。

So these animals apparently spend their lives buried in this sediment, with no oxygen,

因此，這些動物明顯是在沒有氧氣的情況下，埋葬在這種沉積物中，

not only surviving, but thriving.

不只活著而已，還茁壯成長。

Part of this incredible survival might be down to their size.

這種難以置信的生存，部分原因是其大小的關係。

At less than one millimeter long, loriciferans have pretty low energy needs.

鎧甲動物門長不到一毫米，它們對能量的需求也很低。

But they also seem to have some unique adaptations.

但它們似乎也有些獨特的適應力。

For one thing, they don't have mitochondria!

一來是，它們沒有粒線體！

Instead, they have cellular structures that look a lot like hydrogenosomes.

取而代之的是，它們的細胞結構看起來很像製造氫氣的粒線體。

These are organelles that some microbes use to produce energy,

這些胞器是某些微生物用來生產能量用的，

and they use hydrogen ions in place of oxygen.

它們用氫離子來代替氧氣。

Alongside these structures, the researchers also noticed shapes that might be microbes

除了這些結構外，研究人員還注意到，外型可能是微生物

living inside the loriciferans' cells.

住在鎧甲動物門細胞內的原因。

That's intriguing because some anaerobic, single-celled organisms also have symbiotic microbes

這很有趣，因為某些厭氧的單細胞生物

that live alongside their hydrogenosomes.

也有一起住在粒線體的共生微生物。

All in all, it looks like these loriciferans have developed similar cellular structures

總之，這些鎧甲動物門為了以同樣的方式生存，

to anaerobic microbes for living in the same way,

似乎發展出與厭氧微生物相似的細胞結構，

although it's not clear how they did this.

但還不清楚它們是如何做到。

One option is that they retained these adaptations from an earlier ancestor

一種說法是，它們保留古早祖先的這些適應性，

more similar to anaerobic microbes.

與厭氧微生物更相似。

But it's also possible that their ancestors swiped genes from their microbial neighbors,

但是，它們的祖先也可能是偷走微生物鄰居的基因，

allowing them to use the same cellular tricks for survival.

讓它們使用相同的細胞技巧來生存。

Of course, this is an extraordinary claim, and some researchers have doubts.

當然，這是很特別的說法，有些研究人員仍有疑問。

For example, a study published in 2015 looked in the same basin

例如，2015 年發表的一項研究也在同一個盆地進行，

and was unable to find independent evidence of living loriciferans.

卻無法找到鎧甲動物門活著的獨立證據。

The researchers of the original study are still confident in their results,

最初研究的研究人員仍對他們的結果有信心，

but it may take more confirmation to convince everyone.

但可能還需要更多佐證才能使人信服。

If these results do hold up, though,

如果這些結果真的成立，

it could change how we understand the requirements of complex life.

那可能會改變我們對複雜生命的理解。

It would have implications for the diversity of animal life in the world today,

這會對現今動物生命的多樣性產生影響，

for scientists interested in how life got started on an oxygen-deficient early Earth,

對於生命如何在缺氧的地球上孕育所感興趣的科學家，

and maybe even for scientists looking for life elsewhere in the solar system.

甚至對於在太陽系其他地方尋找生命的科學家來說也一樣。

Ultimately, life is so adaptable and endlessly diverse,

最後，生命的適應力很強，還有無限的多樣性，

that we wouldn't be shocked if there are more surprises to be found.

如果發現更多驚喜，也嚇不著我們。

Critical thinking in science is obviously a great thing, though,

科學中的批判性思考顯然是件好事，

and that's why it's so important for researchers to check each other's work.

研究人員為何會確認彼此間的工作，也是如此重要的原因。

And if you want to brush up on your critical thinking skills, or just learn some really cool stuff,

如果你想提高自己批判性思考的能力，或是想學一些很酷的東西，

the Daily Challenges from Brilliant are a great way to do that.

Brilliant 的每日挑戰是個很棒的選擇。

Every day, Brilliant has new challenge questions about math and science topics.

Brilliant 每天都有新的挑戰問題，主題是數學和科學。

They're short, fun, and you can access them every day of the week for free!

它們簡短有趣，你每天都可以免費使用！

Like, I just completed one about black body radiation in a real life setting: a campfire!

像我才剛完成現實的黑體輻射：營火！

If you become a Premium member, you'll also get access to the whole archive of questions.

如果你成為高級會員，你也可以獲得整個問題的檔案。

Best of all, the first 200 people to sign up at Brilliant.org/SciShow,

最棒的是，前 200 名到 Brilliant.org/SciShow 註冊

will get 20% off an annual Premium subscription.

可以獲得年度高級訂閱的 8 折優惠。

And if you check it out, well, hey, thanks for supporting us!

如果你註冊了，嘿，感謝支持我們！