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Wherever there's water on Earth, there's a pretty good chance that you'll find life.
只要地球上有水，你就很有可能找到生命。
Like, even in the driest part of the Atacama Desert in South America,
比如，即使在南美洲阿塔卡马沙漠最干燥的地方
single-celled organisms live in rocks that extract water from the air.
单细胞生物也能生活在从空气中汲取水分的岩石中。
And in Japanese hot springs, there are microbes that survive an acidity on par with battery acid.
在日本的温泉中，有些微生物可以在与电池酸相当的酸性环境中生存。
So, in almost any water that would be deadly to you or me, there's probably something that calls it home.
所以，在几乎所有对你我有害的水质中，都可能有某种东西把它叫做家。
But there are a few places full of water that appear to be completely inhospitable to life:
但有几个地方满是完全不适合生命生存的水：
some super acidic, super salty, and super hot pools in Ethiopia's Dallol geothermal field.
埃塞俄比亚的达洛尔地热田中一些超酸、超咸、超热的水池。
And so far, these pools are the only wet places anyone has found on Earth that don't host life.
到目前为止，这些水池是地球上唯一没有生命存在的潮湿地方。
The Dallol geothermal field is at the top of a volcanic crater filled with salt, and it's a pretty dreadful place to try and live.
达洛尔地热田于一个充满盐的火山口的顶部，是一个非常不适合居住的地方。
It's got toxic gases coming out of cracks in the ground,
有毒气体从地面的裂缝中释放出来，
temperatures above the boiling point of pure water, and ridiculously acidic brines.
温度高于纯水的沸点，还有酸性盐水。
So, these pools aren't exactly jacuzzis. But some scientists who study extremophiles—
所以这些水池可不是极可意浴缸。但是一些研究极端微生物的科学家——
or organisms that live in extreme environments—wondered if anything was possibly alive in there.
或是生活在极端环境中的生物体—想知道这里是否可能有生命的存在。
After all, they'd found a lot of single-cell archaea in nearby areas, including the land around the water,
毕竟，他们在附近区域发现了很多单细胞古生菌，包括水周围的土地，
where conditions aren't as extreme, but aren't exactly homey either. So, between 2016 and 2018,
这片土地并不是极端环境，但是也不适宜居住。所以在2016年到2018年间，
an international team of researchers collected 200 water samples from multiple locations in the area to hunt for life.
一组国际研究人员团队从该地区多个地点采集了200个水样来寻找生命。
They took water from the steaming-hot, extremely acidic ponds at the top of the Dallol dome,
他们从达洛尔顶部热气腾腾、酸性极强的池塘里取水，
as well as from the nearby Black and Yellow Lakes, which were not as hot or acidic but were super salty.
也从附近的黑黄两色湖泊取水，这里的水没有那么热，也没有那么酸，但却非常咸。
And these samples were completely devoid of any native life.
这些样本中完全没有任何原生生物。
The only signs of life scientists detected were bacteria that appeared to have come from humans or the lab equipment.
科学家们发现的唯一生命迹象是来自人类或实验室设备的细菌。
And there were others that might have blown in on dust carried by the wind.
还有一些可能是被风吹来的灰尘吹进来的。
But there was not a single native organism,
但没有一种本土生物，
or any evidence that these foreign cells could actually survive the conditions in the Dallol pools.
也没有证据表明这些外来细胞能在达洛尔的环境中存活。
And there are some pretty good reasons why nothing would want to live there. For one, there's the temperature.
任何生物都不想在此居住的原因有很多。其一是这里的温度。
The temperatures in these pools range from 40 to 108 degrees Celsius.
这些水池的水温在40到108摄氏度间不等。
And when temperatures get too high, molecules that cells need to function, like proteins, start to lose their shape.
水温过高，细胞需要运行的分子，如蛋白质，开始失去形状。
And if they're the wrong shape, they can't do their jobs.
如果形状不对，它们就无法工作。
Which is bad, since they're basically involved in every part of keeping cells up and running.
这很糟糕，因为它们基本上参与了维持细胞正常运转的所有部分。
And under really extreme temperatures, proteins, and even DNA, will just break down altogether.
在极端温度下，蛋白质，甚至是DNA都将完全分解。
That's not the only problem in these pools, either. On top of the heat, they're extremely acidic.
这也不是这些水池中唯一的问题。最重要的是，它们非常酸。
When acids are dissolved in water, they produce hydrogen ions, which are just plain old protons.
当酸溶解于水中，它们会产生氢离子，而氢离子就是普通的质子。
And those ions are eager to chemically react with proteins, which, again, messes with a cell's ability to function.
这些离子渴望与蛋白质发生化学反应，又一次扰乱了细胞的功能。
So high temperature and acidity are a pretty deadly combination. But to top it all off, these pools are also extremely salty.
所以高温和酸是相当致命的结合。但最重要的是，这些水池也非常咸。
Living organisms need some salt in their lives, but too much quickly turns deadly.
生物体需要一些盐，但过多盐分很快就会致命。
If the concentration of salt in water outside a cell is higher than what's on the inside,
如果细胞外水中的盐浓度高于细胞内，
water will rush out of the cell to try to balance everything out...and the cell will shrivel up like a raisin.
水会冲出细胞以试图平衡一切…并且细胞会像葡萄干一样皱缩。
So that's bad to begin with, but certain salty solutions are extra-deadly.
这就是糟糕的开始，但某些含盐溶液是非常致命的。
Some salt ions, like magnesium, are what's called chaotropic, because they cause chaos.
一些盐离子，比如镁，离液序列高，因为它们会引起混乱。
They break hydrogen bonds between water molecules,
它们会破坏水分子之间的氢键，
which can then lead to the breakdown of the complex molecules that organisms need to live and function.
从而导致生物体赖以生存和运作的复杂分子的分解。
In case that's not bad enough, these ions also interact with water molecules
如果这还不够糟糕的话，这些离子还会与水分子相互作用，
in a way that prevents cells from being able to use that water in important chemical reactions.
阻止细胞在重要的化学反应中利用这些水。
So these ponds are not welcoming to living things. But it's still kind of surprising that there's nothing living there.
所以这些水池并不欢迎生物的到来。但是令人惊讶的是，那里什么都没有。
Because, as deadly as these conditions are, around the planet,
因为，尽管这些环境是致命的，
there are certain extremophiles that can deal with some of these ridiculous challenges.
某些极端微生物可以应对这些荒谬的挑战。
For example, thermophiles have extra-hardy proteins with extra bonds built in that help them hold their shape.
例如，嗜热菌有特别耐寒的蛋白质，它们有额外的键来帮助它们保持形状。
Some of them also have special proteins to repair molecules that have been damaged by heat.
其中一些还含有特殊的蛋白质来修复被热损坏的分子。
And then there are the so-called acidophiles, which are either really good at pumping protons out of their cells,
还有所谓的嗜酸菌，它们要么非常擅长把质子泵出细胞，
or have special compounds to help keep protons out entirely.
要么有特殊的化合物帮助把质子完全挡在外面。
And there are halophiles, which have have evolved to tolerate extreme salinity.
还有嗜盐菌，它们已经进化到可以忍受极端的盐度。
For example, some of them build up a bunch of potassium ions
例如，其中一些在内部形成大量钾离子
or other compounds on the inside to balance out extreme salinity on the outside.
或其他化合物，以平衡外部的极端盐度。
So there are single-celled organisms that can handle extreme environments.
所以有些单细胞生物可以应对极端环境。
And there's even life that can handle more than one of these deadly conditions at a time.
甚至有生命可以同时应对以上几种致命的情况。
But the Dallol pools seem to be especially deadly. And no one knows exactly why, but there are a few ideas.
但达洛尔水池似乎特别致命。没人知道为什么，但是有几种猜想。
It may be that its conditions are on the extreme end of extreme.
或许这的环境是极端中的极端。
Like, the salinity in the Black and Yellow Lakes is over 50 percent, meaning that the lake is half salt.
比如，黑湖和黄湖的盐度超过50%，这意味着这个湖有一半是盐。
For comparison, the ocean's salinity is about 3.5%. These lakes also have high concentrations of those chaotropic salts,
相比之下，海洋盐度约为3.5%。这些湖泊还含有高浓度的朝热带盐，
like magnesium chloride and calcium chloride, that make salty solutions especially deadly.
如氯化镁和氯化钙，这些盐溶液特别致命。
And to make matters worse, there's the one-two punch of extreme salinity and acidity.
更糟糕的是，这里有极端的盐度和酸度。
Scientists aren't sure what, exactly, is so deadly about that combination, but even with so many extremophiles in the world,
科学家们不确定这种组合到底有什么致命的地方，但即使世界上有这么多极端微生物，
no one has yet found any organism that can tolerate both high salinity and high acidity, which is what you've got in these pools.
目前还没有人发现任何一种生物能够同时忍受高盐度和高酸性，而这正是你在这些水池中所发现的。
Scientists may one day find some other wet part of Earth too extreme to harbor life.
有一天，科学家们可能会发现地球上其他一些湿润的地方太过极端，无法孕育生命。
Or maybe future tests will find something that can survive these seemingly inhospitable pools.
或者，未来的测试可能会发现一些东西可以在这些看似不适宜居住的水池中存活下来。
Either way, research like this helps scientists understand what it takes for life as we know it to survive,
不管怎样，这样的研究有助于科学家理解我们所知道的生命生存所需要的条件，
which can be a good starting point when it comes to looking for life beyond Earth.
这是寻找地球以外生命的一个良好起点。
Thanks for watching this episode of SciShow!
感谢收看本期节目！
And if you want to learn about one extreme place on Earth that does host life,
如果你想了解地球上有生命存在的一个极端地区，
you might like this episode on tiny organisms that live inside solid rock. You can check it out next!
你可能会喜欢这期关于生活在坚硬岩石里的微生物的那一期节目。你可以下次再来看看！
