This deep-sea mystery is changing our understanding of life | Karen Lloyd

翻译人员: Sai Lu 校对人员: Yolanda Zhang

I'm an ocean microbiologist at the University of Tennessee,

我是田纳西大学的 一位海洋微生物科学家，

and I want to tell you guys about some microbes

我想告诉大家，有一些微生物

that are so strange and wonderful

非常的奇特与美妙，

that they're challenging our assumptions about what life is like on Earth.

它们挑战着 我们对地球上生命的认知。

So I have a question.

我想问大家一个问题。

Please raise your hand if you've ever thought it would be cool

如果你曾经觉得坐潜水艇去海底

to go to the bottom of the ocean in a submarine?

很酷的话，请举起你的手。

Yes.

很好。

Most of you, because the oceans are so cool.

大部分人都举了手， 因为海洋真的很酷！

Alright, now -- please raise your hand

好的，那如果

if the reason you raised your hand to go to the bottom of the ocean

你想去海底的原因是 这会让你更加接近

海底令人激动人心的泥，

is because it would get you a little bit closer

to that exciting mud that's down there.

请举起你的手。

(Laughter)

(笑声)

Nobody.

没人啊！

I'm the only one in this room.

我是这个屋子里的唯一一个。

Well, I think about this all the time.

好的，我总是在想，

I spend most of my waking hours

我每天醒来后的大部分时间

trying to determine how deep we can go into the Earth

都花在决定我们可以 探入地球多深这件事上，

and still find something, anything, that's alive,

并且还会发现有一些活着的生命，

because we still don't know the answer to this very basic question

因为我们还是不知道 关于地球上的生命这个

最基本问题的答案。

about life on Earth.

So in the 1980s, a scientist named John Parkes, in the UK,

在上世纪80年代，一位叫做 约翰·派克斯的英国科学家，

was similarly obsessed,

也同样沉迷于这个问题，

and he came up with a crazy idea.

他想出了一个疯狂的点子。

He believed that there was a vast, deep, and living microbial biosphere

他相信在全世界的海洋底部 都有一个巨大，深邃，生机勃勃的

underneath all the world's oceans

微生物圈，

that extends hundreds of meters into the seafloor,

深入海床达几百米，

which is cool,

听起来很酷，

but the only problem is that nobody believed him,

可是唯一的问题是，没人相信他，

and the reason that nobody believed him

而其背后的原因是

is that ocean sediments may be the most boring place on Earth.

海洋的沉积处可能是 地球上最枯燥乏味的地方了。

(Laughter)

（笑声）

There's no sunlight, there's no oxygen,

那里没有阳光，没有氧气，

and perhaps worst of all,

可能最坏的情况是，

there's no fresh food deliveries for literally millions of years.

那里没有新鲜的食物供给 已经持续长达几百万年。

你不需要一个生物学博士学位

You don't have to have a PhD in biology

to know that that is a bad place to go looking for life.

就会知道那里不是一个 寻找生命的好地方。

(Laughter)

（笑声）

But in 2002, [Steven D'Hondt] had convinced enough people

但是在2002年， 约翰说服了足够多的人

that he was on to something that he actually got an expedition

相信他会有新发现， 于是他得到了一个在一艘叫做

on this drillship, called the JOIDES Resolution.

乔伊斯决心号的 钻探船上考察的机会。

And he ran it along with Bo Barker Jørgensen of Denmark.

他和来自丹麦的波巴克·约金森 一同进行了那次考察。

And so they were finally able to get

他们终于可以拿到

good pristine deep subsurface samples

真正的深海下表层的样本，

some really without contamination from surface microbes.

没有接触到任何 表层微生物的污染。

This drill ship is capable of drilling thousands of meters underneath the ocean,

这艘钻探船可以钻进海底几千米，

and the mud comes up in sequential cores, one after the other --

泥被储存在一个接一个的 管子里按顺序被打上来，

long, long cores that look like this.

就像这样长长的管子。

This is being carried by scientists such as myself who go on these ships,

然后由像我这样 在船上的科学家拿着，

and we process the cores on the ships and then we send them home

在船上处理重要的部分， 然后把它们送回

to our home laboratories for further study.

实验室，再进行更深入的研究。

So when John and his colleagues

当约翰和他的同事们

got these first precious deep-sea pristine samples,

初次拿到了这些宝贵， 新鲜干净的深海样本时，

they put them under the microscope,

他们把样本放在了显微镜下，

and they saw images that looked pretty much like this,

并看到了像这样的图片，

which is actually taken from a more recent expedition

这其实是最近一次考察拿来的样本，

数据来自我的博士学生， Joy Buongiorno。

by my PhD student, Joy Buongiorno.

You can see the hazy stuff in the background.

你们可以看到背景有些雾蒙蒙的东西。

That's mud. That's deep-sea ocean mud,

那是泥，深海泥，

and the bright green dots stained with the green fluorescent dye

亮亮的绿点，被绿色荧光染色的

are real, living microbes.

是真的，活着的微生物。

Now I've got to tell you something really tragic about microbes.

现在我需要告诉你们 微生物真正悲剧的地方。

They all look the same under a microscope,

它们在显微镜下看起来都一样。

I mean, to a first approximation.

我是说，初次预测的时候。

You can take the most fascinating organisms in the world,

你可以拿着世界上 最迷人的有机组织，

like a microbe that literally breathes uranium,

比如说一个可以呼吸铀的微生物，

and another one that makes rocket fuel,

和一个可以产生火箭燃料的微生物，

mix them up with some ocean mud,

把它们和一些深海泥混在一起，

put them underneath a microscope,

然后把它们放在显微镜下观察。

and they're just little dots.

它们只会是一个个小点点，

It's really annoying.

很让人抓狂。

So we can't use their looks to tell them apart.

所以我们不能通过 它们的样子来辨别它们。

We have to use DNA, like a fingerprint,

我们需要用DNA, 像指纹一样

to say who is who.

来分清谁是谁。

And I'll teach you guys how to do it right now.

我现在来教你们怎么做。

So I made up some data, and I'm going to show you some data that are not real.

我编了一些数据， 我要给大家展示这些模拟数据。

This is to illustrate what it would look like

只是为了展示如果 一群物种彼此之间毫无联系，

if a bunch of species were not related to each other at all.

数据看起来应该是什么样子。

So you can see each species

你可以看到每个物种

has a list of combinations of A, G, C and T,

有一系列由A, G, C, T组成的组合，

which are the four sub-units of DNA,

这些是DNA的四个碱基对，

sort of randomly jumbled, and nothing looks like anything else,

几乎是随机地乱成一团， 彼此看起来毫无相似之处，

and these species are totally unrelated to each other.

这些物种彼此之间毫无关联。

But this is what real DNA looks like,

但这是真正的DNA，

from a gene that these species happen to share.

这些物种共享的基因。

Everything lines up nearly perfectly.

所有碱基都完美的排列着。

The chances of getting so many of those vertical columns

得到这些竖着的列的概率

where every species has a C or every species has a T,

比如每个物种在这列都有个c， 或者在这列都有个t的

by random chance, are infinitesimal.

随机概率是无穷小的。

So we know that all those species had to have had a common ancestor.

我们了解到所有的物种 是需要有一个共同的祖先的。

They're all relatives of each other.

它们彼此都是亲戚。

So now I'll tell you who they are.

现在我来告诉大家它们到底是谁。

The top two are us and chimpanzees,

最上边的两个是人类和大猩猩，

which y'all already knew were related, because, I mean, obviously.

我们都知道了这两个物种 是有关联的，这很明显吧。

(Laughter)

(笑声)

But we're also related to things that we don't look like,

但是我们也和很多跟我们 不相像的物种有联系，

like pine trees and Giardia, which is that gastrointestinal disease

比如，松树、贾第虫， 一种肠胃疾病，

you can get if you don't filter your water while you're hiking.

如果你徒步时在山上喝了没有经过 过滤的水的话，可能会得这种病。

We're also related to bacteria like E. coli and Clostridium difficile,

我们与大肠杆菌和 艰难梭菌也有联系，

which is a horrible, opportunistic pathogen that kills lots of people.

艰难梭菌是一种特别不好的 爱钻空子的病原体，杀死了很多的人。

But there's of course good microbes too, like Dehalococcoides ethenogenes,

但也有很多对我们有益的微生物， 比如产乙烯脱卤拟球菌，

which cleans up our industrial waste for us.

它们可以帮助我们清洁工业废物。

So if I take these DNA sequences,

如果我用这些DNA序列，

and then I use them, the similarities and differences between them,

用它们的相同和不同之处

to make a family tree for all of us

做一个家谱的话，

so you can see who is closely related,

你可以看到谁跟谁联系更紧密，

then this is what it looks like.

它们看起来是这样的。

So you can see clearly, at a glance,

你可以清楚的看出来，

that things like us and Giardia and bunnies and pine trees

我们人类和贾第虫，兔子，还有松树

are all, like, siblings,

都像是亲兄弟姐妹，

细菌则像我们的远古表亲。

and then the bacteria are like our ancient cousins.

But we're kin to every living thing on Earth.

但我们跟地球上的 生物都有亲戚关系。

So in my job, on a daily basis,

我每天的工作就是，

I get to produce scientific evidence against existential loneliness.

提供科学证据来 反驳我们是孤独存在着的物种。

So when we got these first DNA sequences,

所以当我们在第一艘钻探船上拿到

from the first cruise, of pristine samples from the deep subsurface,

深海底部样品的第一个DNA序列时，

we wanted to know where they were.

我们想知道它们位于 这个家谱上的什么位置。

So the first thing that we discovered is that they were not aliens,

我们发现的第一件事是， 它们不是外星人，

because we could get their DNA to line up with everything else on Earth.

它们的DNA可以跟地球上的 其他生物排在一起。

But now check out where they go on our tree of life.

但是看它们在这个家谱上的位置。

The first thing you'll notice is that there's a lot of them.

你们首先会注意到的是， 它们有很多种类，

It wasn't just one little species

不是一个小小的物种

that managed to live in this horrible place.

存活在恶劣的环境下。

It's kind of a lot of things.

而是很多东西并存。

你们也许会注意到的第二点就是，

And the second thing that you'll notice,

它们与我们之前见过的 东西一点儿都不像。

hopefully, is that they're not like anything we've ever seen before.

They are as different from each other

它们彼此也大不相同，

as they are from anything that we've known before

就像和我们已知的物种很不同一样，

as we are from pine trees.

就像我们跟松树的不同。

So John Parkes was completely correct.

所以约翰·帕克思是完全正确的。

He, and we, had discovered a completely new and highly diverse

他，和我们，发现了一个 崭新并高度多样化的

microbial ecosystem on Earth

地球微生物圈，

that no one even knew existed before the 1980s.

而在80年代以前没人知道它的存在。

So now we were on a roll.

现在我们手气正旺，

The next step was to grow these exotic species in a petri dish

下一步是在培养基上 培养这些奇异的物种，

so that we could do real experiments on them

这样就可以用它们 做真正的科学实验，

like microbiologists are supposed to do.

做微生物学家该做的工作。

But no matter what we fed them,

可是不管我们喂给它们什么，

they refused to grow.

它们都不成长。

Even now, 15 years and many expeditions later,

甚至在15年后的现在， 经历了许多科学考察之后。

no human has ever gotten a single one of these exotic deep subsurface microbes

仍然没有人可以让 那些来自深海的微生物

to grow in a petri dish.

在培养基上长大。

And it's not for lack of trying.

这不是因为缺乏尝试。

That may sound disappointing,

这也许听起来很令人失望，

but I actually find it exhilarating,

但我却觉得这令人振奋，

because it means there are so many tantalizing unknowns to work on.

因为这意味着有许许多多 未知有待发掘。

Like, my colleagues and I got what we thought was a really great idea.

比如，我和同事 想出了一个特别好的点子。

We were going to read their genes like a recipe book,

我们打算像读菜谱一样 读取它们的基因，

find out what it was they wanted to eat and put it in their petri dishes,

发现它们想吃什么， 然后放在培养基上，

and then they would grow and be happy.

这样它们就会快乐地长大。

But when we looked at their genes,

但是当我们检查它们基因的时候，

it turns out that what they wanted to eat was the food we were already feeding them.

发现它们想吃的食物 我们已经在喂了。

So that was a total wash.

所以那个点子就废了。

There was something else that they wanted in their petri dishes

就是说，在培养基上， 它们想要的其他东西

that we were just not giving them.

我们并没有提供。

So by combining measurements from many different places

把从世界不同地方的测量数据

around the world,

结合到一起时，

my colleagues at the University of Southern California,

我在南加州大学的同事们

Doug LaRowe and Jan Amend,

Doug LaRowe和Jan Amend，

were able to calculate that each one of these deep-sea microbial cells

成功计算出了每个深海微生物

requires only one zeptowatt of power,

只需要一仄普托（zepto）瓦的能量，

and before you get your phones out, a zepto is 10 to the minus 21,

别忙着掏手机， 一个仄普托是10的负21次方。

because I know I would want to look that up.

要是我肯定是会查一下的。

Humans, on the other hand,

另一方面，人类

require about 100 watts of power.

需要100瓦的能量。

So 100 watts is basically if you take a pineapple

100瓦是你拿一个菠萝，

and drop it from about waist height to the ground 881,632 times a day.

然后每天从你腰部那么高的地方 丢到地上88万1632次。

If you did that and then linked it up to a turbine,

如果你连上一个涡轮 这么做了的话，

that would create enough power to make me happen for a day.

你就可以创造足够支撑我 一整天的能量。

A zeptowatt, if you put it in similar terms,

一仄普托瓦，用一个类似的比较，

is if you take just one grain of salt

如果你拿一粒盐做参照物，

and then you imagine a tiny, tiny, little ball

然后你想象一个很小很小很小的球，

that is one thousandth of the mass of that one grain of salt

大约是一粒盐重量的1/1000，

and then you drop it one nanometer,

然后你把它丢下1纳米的高度，

which is a hundred times smaller than the wavelength of visible light,

一纳米大约是 可见光波长的1/100的长度，

once per day.

每天丢一次。

That's all it takes to make these microbes live.

这就是这些微生物存活需要的能量。

That's less energy than we ever thought would be capable of supporting life,

比我们之前想的 可以支撑生命的能量要少很多，

but somehow, amazingly, beautifully,

但是让人惊讶，却十分美妙的是，

it's enough.

这就够了。

So if these deep-subsurface microbes

如果这些海洋底部下的微生物

have a very different relationship with energy than we previously thought,

跟能量之间有一个与我们之前 假设的不一样的关系，

then it follows that they'll have to have

那么接下来就是它们需要

与时间之间也有不同的关系，

a different relationship with time as well,

because when you live on such tiny energy gradients,

因为如果你靠着 这么微小的能量生活，

rapid growth is impossible.

快速成长是不可能的。

If these things wanted to colonize our throats and make us sick,

如果这些微生物想占领我们的喉咙 然后让我们生病，

they would get muscled out by fast-growing streptococcus

它们会在第一次分裂发生前

before they could even initiate cell division.

被快速繁殖的链球菌踢出局。

So that's why we never find them in our throats.

所以我们不会在喉咙里找到它们。

Perhaps the fact that the deep subsurface is so boring

也许深海的下表层 极度无聊的环境

is actually an asset to these microbes.

其实是对这些微生物 来说是一种财富。

They never get washed out by a storm.

它们不会被一场风暴冲刷走。

They never get overgrown by weeds.

它们不会被海草覆盖。

All they have to do is exist.

它们要做的就是存在着。

Maybe that thing that we were missing in our petri dishes

也许我们在培养基上缺少的

was not food at all.

根本不是食物。

Maybe it wasn't a chemical.

也许都不是任何化学物质。

Maybe the thing that they really want,

也许它们真正想要的，

the nutrient that they want, is time.

它们想要的营养是，时间。

But time is the one thing that I'll never be able to give them.

但是时间是唯一 我没法给它们的东西。

So even if I have a cell culture that I pass to my PhD students,

即使我有一个细胞群可以 传给我的博士生，

who pass it to their PhD students, and so on,

然后他们会传给他们的 博士生，如此延续，

we'd have to do that for thousands of years

都需要传上个几千年

in order to mimic the exact conditions of the deep subsurface,

才能模仿出深海的环境，

all without growing any contaminants.

这还是在无任何污染的情况下。

It's just not possible.

这是完全不可能做到的。

But maybe in a way we already have grown them in our petri dishes.

但也许我们已经在我们的 培养基上繁殖它们了。

Maybe they looked at all that food we offered them and said,

也许它们看看我们给的食物说，

"Thanks, I'm going to speed up so much

“谢谢，我决定加速繁殖，

that I'm going to make a new cell next century.

要在下个世纪分裂一个新细胞。”

Ugh.

唉.....

(Laughter)

(笑声)

那为什么其他的生物动作那么快？

So why is it that the rest of biology moves so fast?

Why does a cell die after a day

为什么一个细胞一天就死亡了，

and a human dies after only a hundred years?

一个人在一百年后就会死亡？

These seem like really arbitrarily short limits

当你想到宇宙中的时间总和，

when you think about the total amount of time in the universe.

这些看起来就都是 很短的随机限制了。

But these are not arbitrary limits.

但这些并不是毫无规律的限制。

They're dictated by one simple thing,

它们被一个东西主宰着，

and that thing is the Sun.

那就是太阳。

Once life figured out how to harness the energy of the Sun

当生命弄清怎么通过光合作用

through photosynthesis,

从太阳获取能量，

we all had to speed up and get on day and night cycles.

我们不得不加速， 然后适应白日黑夜的轮回。

In that way, the Sun gave us both a reason to be fast

在这个意义上，太阳给了 我们一个加速的理由，

and the fuel to do it.

也给了我们加速的原料。

You can view most of life on Earth like a circulatory system,

你可以把地球上大多数生命 看成一个循环系统，

and the Sun is our beating heart.

太阳就是我们跳动着的心脏。

But the deep subsurface is like a circulatory system

而深海下表层也像一个 与太阳完全隔离的

that's completely disconnected from the Sun.

循环系统。

It's instead being driven by long, slow geological rhythms.

它的演变在被漫长的地质韵律驱使。

There's currently no theoretical limit on the lifespan of one single cell.

一个单细胞的生命长度 目前还没有理论上的限制。

As long as there is at least a tiny energy gradient to exploit,

只要有一丁点儿的能量可以用，

theoretically, a single cell could live

理论上讲，一个细胞可以存活

for hundreds of thousands of years or more,

几十万年甚至更久，

simply by replacing broken parts over time.

必要时换掉坏的部件就可以了。

To ask a microbe that lives like that to grow in our petri dishes

让一个微生物在我们的培养皿中 那样存活，就等于是在

is to ask them to adapt to our frenetic, Sun-centric, fast way of living,

要求它们来适应我们疯狂的 以太阳为中心的快速生活方式，

and maybe they've got better things to do than that.

也许它们有其他 更重要的事情要做呢。

(Laughter)

(笑声)

Imagine if we could figure out how they managed to do this.

想象一下，如果我们可以 弄清它们怎么做到的。

What if it involves some cool, ultra-stable compounds

如果这其中包含着某些 特别酷，特别稳定的化合物

that we could use to increase the shelf life

可以被利用来提高生物医药产品和

in biomedical or industrial applications?

工业产品的有效期，会怎么样？

Or maybe if we figure out the mechanism that they use

或许我们可以研究出它们之所以可以

to grow so extraordinarily slowly,

成长得如此缓慢的机制，

we could mimic it in cancer cells and slow runaway cell division.

那我们就可以在癌细胞中 模拟这个机制，从而减缓癌细胞的分裂。

I don't know.

我也不知道。

I mean, honestly, that is all speculation,

那些都只是我的猜测，

but the only thing I know for certain

但是我唯一可以确定的是，

is that there are a hundred billion billion billlion

有着数目无法估量的

living microbial cells

活着的微生物细胞

underlying all the world's oceans.

待在全世界海洋的底部。

That's 200 times more than the total biomass of humans on this planet.

相当于地球上全部人类生物质 总和的200多倍。

And those microbes have a fundamentally different relationship

从本质上说，比起人类， 那些微生物与时间和能量

with time and energy than we do.

有着不同的关系。

What seems like a day to them

它们世界中的一天

might be a thousand years to us.

可能对我们而言像是几千年。

They don't care about the Sun,

它们才不管太阳呢，

and they don't care about growing fast,

也不屑于快速的繁殖，

and they probably don't give a damn about my petri dishes ...

它们可能也不在意 呆在我的培养皿里...

(Laughter)

（笑声）

but if we can continue to find creative ways to study them,

但是如果我们继续去 发现新的方法来研究它们，

then maybe we'll finally figure out what life, all of life, is like on Earth.

那么也许我们最终可以 搞清楚地球上全部的生命。

Thank you.

谢谢大家。

(Applause)

（鼓掌）