but we're not.

我們看似腳踏在堅實的地表上，

The rocks and the dirt underneath us are crisscrossed by tiny little fractures

但其實並非如此。

and empty spaces.

地底下的岩石與塵埃 藉著微小的碎裂物

And these empty spaces are filled with astronomical quantities of microbes,

與空間相互交錯著。

such as these ones.

這些空間被數不清的微生物填滿，

The deepest that we found microbes so far into the earth

如同這些。

is five kilometers down.

我們目前在地球上發現微生物

So like, if you pointed yourself at the ground

最深達距地面五公里。

and took off running into the ground,

就好像，若你把自己固定在地面上，

you could run an entire 5K race and microbes would line your whole path.

然後開始往地底跑，

So you may not have ever thought about these microbes

微生物可以排一整路，全程五公里。

that are deep inside earth's crust,

你可能從沒想到過這些

but you probably thought about the microbes living in our guts.

在地殼深處的微生物，

If you add up the gut microbiomes

但你可能會想到 住在我們消化道中的微生物。

of all the people and all the animals on the planet,

如果你將地球上所有人與動物

collectively, this weighs about 100,000 tons.

體內的微生物全部相加，

This is a huge biome that we carry in our bellies every single day.

總共可重達十萬噸。

We should all be proud.

我們的肚子每天都扛著 如此巨大的生物群。

(Laughter)

我們應該都要感到自豪。

But it pales in comparison to the number of microbes

（笑聲）

that are covering the entire surface of the earth,

但跟覆蓋在地表的微生物數量相比，

like in our soils, our rivers and our oceans.

可就相形見絀了。

Collectively, these weigh about two billion tons.

例如在土壤中、河流中， 以及海洋中的微生物。

But it turns out that the majority of microbes on earth

這些地方的微生物量 總共約 20 億噸。

aren't even in oceans or our guts or sewage treatment plants.

然而令人意外的是， 大多數在地球上的微生物

Most of them are actually inside the earth's crust.

並不存在於海洋、 消化系統或污水處理廠中，

So collectively, these weigh 40 billion tons.

它們大多存在於地殼中。

This is one of the biggest biomes on the planet,

這些總重達 400 億噸。

and we didn't even know it existed until a few decades ago.

這是地球上最大的生物群之一，

So the possibilities for what life is like down there,

而我們直到幾十年前才知道它的存在。

or what it might do for humans,

因此在地表下的生活如何，

are limitless.

或它會如何影響人類，

This is a map showing a red dot

是無限的。

for every place where we've gotten pretty good deep subsurface samples

這是個地圖，地圖上的紅點代表

with modern microbiological methods,

每一個我們藉現代微生物研究法

and you may be impressed

已取得不錯的地底樣本的地方，

that we're getting a pretty good global coverage,

你可能會欽佩我們

but actually, if you remember that these are the only places

受到全球報導關注，

that we have samples from, it looks a little worse.

但事實上，如果你記得這些點是

If we were all in an alien spaceship,

我們唯一能找到樣本的地方， 這看起來就會有點糟糕。

trying to reconstruct a map of the globe from only these samples,

如果我們現在在一個外星船上，

we'd never be able to do it.

想靠這些樣本重建地球的地圖，

So people sometimes say to me,

是辦不到的。

"Yeah, there's a lot of microbes in the subsurface, but ...

因此有時候會有人跟我說：

aren't they just kind of dormant?"

「對，地表下有很多微生物，可是...

This is a good point.

它們不都在休眠狀態嗎？」

Relative to a ficus plant or the measles or my kid's guinea pigs,

這是一個很好的論點。

these microbes probably aren't doing much of anything at all.

相對於榕屬植物、麻疹， 或我的孩子養的天竺鼠，

We know that they have to be slow, because there's so many of them.

這些微生物看似 對我們沒有什麼影響。

If they all started dividing at the rate of E. coli,

我們知道它們的影響必是緩慢的， 因為它們數量很大。

then they would double the entire weight of the earth, rocks included,

如果它們他們開始 以大腸桿菌的速率分裂，

over a single night.

它們會在一夜之間使地球，

In fact, many of them probably haven't even undergone a single cell division

包含岩石的重量加倍。

since the time of ancient Egypt.

事實上，很多微生物 甚至自古埃及時期以來，

Which is just crazy.

尚未經歷任何細胞分裂活動，

Like, how do you wrap your head around things that are so long-lived?

非常不可思議。

But I thought of an analogy that I really love,

該如何理解這種如此長壽的東西？

but it's weird and it's complicated.

但我想到了一個我很愛的比擬，

So I hope that you can all go there with me.

但它很怪也很複雜。

Alright, let's try it.

我希望你們可以跟著我。

It's like trying to figure out the life cycle of a tree ...

好，我們來試試看。

if you only lived for a day.

這就好像你只活一天，

So like if human life span was only a day, and we lived in winter,

但你卻想弄清楚 一棵樹的生命週期一樣。

then you would go your entire life

所以如果人的壽命只有一天， 而且我們活著的時候是冬天，

without ever seeing a tree with a leaf on it.

那麼你將一輩子

And there would be so many human generations

看不到樹上長葉子。

that would pass by within a single winter

而一個冬天就會有好幾個

that you may not even have access to a history book

人類的世代輪替，

that says anything other than the fact that trees are always lifeless sticks

甚至你沒有機會

that don't do anything.

看到歷史書上寫著：

Of course, this is ridiculous.

樹就是沒有生命也沒有功用的棍子。

We know that trees are just waiting for summer

當然，這很荒謬。

so they can reactivate.

我們知道樹只是在等待夏天，

But if the human life span

夏天一到他們就能恢復活動。

were significantly shorter than that of trees,

但如果人類的生命週期

we might be completely oblivious to this totally mundane fact.

遠比樹木們來得短，

So when we say that these deep subsurface microbes are just dormant,

我們可能不會知道 這個平凡無奇的事實。

are we like people who die after a day, trying to figure out how trees work?

所以當我們說這些 地底深層的微生物在休眠，

What if these deep subsurface organisms

我們是不是就如同那些一天就死， 卻想研究樹木生命的人呢？

are just waiting for their version of summer,

會不會這些地底深處的微生物

but our lives are too short for us to see it?

只是在等待它們的夏天，

If you take E. coli and seal it up in a test tube,

而我們的壽命短得 不足以見證這件事呢？

with no food or nutrients,

如果你把大腸桿菌放進密閉的試管中，

and leave it there for months to years,

不提供食物或養分，

most of the cells die off, of course, because they're starving.

就這樣放好幾個月或好幾年，

But a few of the cells survive.

當然，大多數的細胞 會因為飢餓而死亡，

If you take these old surviving cells

但有一些細胞存活。

and compete them, also under starvation conditions,

若你拿這些舊有生存下來的細胞

against a new, fast-growing culture of E. coli,

與新培養出來 成長快速的大腸桿菌相比，

the grizzled old tough guys beat out the squeaky clean upstarts

同樣在飢餓的情境下，

every single time.

這些老細胞每一次都戰勝

So this is evidence there's actually an evolutionary payoff

那些新細胞。

to being extraordinarily slow.

這就是它們演化如此緩慢

So it's possible

但有成果的證據。

that maybe we should not equate being slow with being unimportant.

因此可能我們不該

Maybe these out-of-sight, out-of-mind microbes

將緩慢與不重要劃上等號。

could actually be helpful to humanity.

這些我們看不見、想不到的微生物

OK, so as far as we know,

可能對人類有實質幫助。

there are two ways to do subsurface living.

就我們目前所知道的，

The first is to wait for food to trickle down from the surface world,

有兩種在地底下生活的方式：

like trying to eat the leftovers of a picnic that happened 1,000 years ago.

第一種是等待食物從地表上往下滴，

Which is a crazy way to live,

就好像試著吃一千年前的 野餐剩餘的碎屑。

but shockingly seems to work out for a lot of microbes in earth.

這是個很瘋狂的生活方法，

The other possibility is for a microbe to just say,

但令人吃驚的是，似乎很多地球上的 微生物是這樣生活的。

"Nah, I don't need the surface world.

另一個可能性是微生物説：

I'm good down here."

「吶，我不需要地表世界的東西，

For microbes that go this route,

我在下面活得很好。」

they have to get everything that they need in order to survive

對於這一類的微生物，

from inside the earth.

它們必須從地球的內部

Some things are actually easier for them to get.

收集它們生活所需的一切。

They're more abundant inside the earth,

有些東西反而在地底容易取得，

like water or nutrients, like nitrogen and iron and phosphorus,

這些資源在地球內部充足——

or places to live.

像水或養分，如氮、鐵和磷——

These are things that we literally kill each other to get ahold of

是宜居之處。

up at the surface world.

這些東西在地表上

But in the subsurface, the problem is finding enough energy.

是生物互相殘殺才能取得的。

Up at the surface,

但在地底下最大的問題 是尋找足夠的能量。

plants can chemically knit together carbon dioxide molecules into yummy sugars

在地表上，

as fast as the sun's photons hit their leaves.

植物可以在陽光的光子 碰到葉子的同時

But in the subsurface, of course, there's no sunlight,

就能藉由化學反應 將二氧化碳分子轉換成美味的糖。

so this ecosystem has to solve the problem

但在地底下沒有陽光，

of who is going to make the food for everybody else.

所以這裡的生態系就必須解決

The subsurface needs something that's like a plant

誰要為大家提供食物的問題。

but it breathes rocks.

地底下需要類似植物

Luckily, such a thing exists,

但藉著石頭呼吸的東西。

and it's called a chemolithoautotroph.

幸運的是，這樣的東西確實存在，

(Laughter)

叫作「化能自養生物」。 （chemolithoautotroph）

Which is a microbe that uses chemicals -- "chemo,"

（笑聲）

from rocks -- "litho,"

也就是使用化學物質——chemo

to make food -- "autotroph."

來源是岩石——lithos

And they can do this with a ton of different elements.

來製造養分——autotroph。

They can do this with sulphur, iron, manganese, nitrogen, carbon,

它們可以利用很多種 不同的元素來進行，

some of them can use pure electrons, straight up.

可以使用硫磺、鐵、錳、氮、碳，

Like, if you cut the end off of an electrical cord,

有些還可以使用純電子。

they could breathe it like a snorkel.

比方說，你把電線的尾端剪掉，

(Laughter)

它們可以把它當潛水呼吸管吸。

These chemolithoautotrophs

（笑聲）

take the energy that they get from these processes

這些化能自養生物

and use it to make food, like plants do.

利用從這些步驟取得的能量

But we know that plants do more than just make food.

來製造養分，就像植物一樣。

They also make a waste product, oxygen,

但我們知道植物不只製造養分，

which we are 100 percent dependent upon.

它們還製造對它無用的 副產品——氧氣，

But the waste product that these chemolithoautotrophs make

也就是我們百分之百依賴著的氧氣。

is often in the form of minerals,

但這些化能自養生物 所製造出來無用的副產品

like rust or pyrite, like fool's gold,

大多以礦物質的形式存在，

or carminites, like limestone.

像是鏽或硫化礦，像是愚人金，

So what we have are microbes that are really, really slow, like rocks,

或砷鉛鐵礦，像石灰岩。

that get their energy from rocks,

所以這些微生物很緩慢、 很緩慢地，如同石頭一般，

that make as their waste product other rocks.

從岩石取得能量，

So am I talking about biology, or am I talking about geology?

再將無用的副產品變成其他岩石。

This stuff really blurs the lines.

那我到底是在討論生物學 還是地理學呢？

(Laughter)

這界線實在很模糊。

So if I'm going to do this thing,

（笑聲）

and I'm going to be a biologist who studies microbes

我如果要做，

that kind of act like rocks,

就得是生物學家，

then I should probably start studying geology.

研究行為像岩石的微生物，

And what's the coolest part of geology?

我也應該研讀地理學。

Volcanoes.

地理學最酷的部份是什麼？

(Laughter)

火山。

This is looking inside the crater of Poás Volcano in Costa Rica.

（笑聲）

Many volcanoes on earth arise because an oceanic tectonic plate

這是向哥斯大黎加的波阿斯 （Poás Volcano）火山口往看的樣子。

crashes into a continental plate.

許多地球上火山的形成都是因為

As this oceanic plate subducts

海洋板塊衝撞大陸板塊。

or gets moved underneath this continental plate,

當這個海洋板塊隱沒，

things like water and carbon dioxide and other materials

或被移動到這個大陸板塊下方時，

get squeezed out of it,

水、二氧化碳或其他物質

like ringing a wet washcloth.

就會被擠壓出來，

So in this way, subduction zones are like portals into the deep earth,

就像擰乾濕毛巾一樣。

where materials are exchanged between the surface and the subsurface world.

如此一來，隱沒帶就像 通往地底深處的門戶，

So I was recently invited by some of my colleagues in Costa Rica

地表與地底的物質在此交換。

to come and work with them on some of the volcanoes.

我最近受哥斯大黎加同事之邀，

And of course I said yes, because, I mean, Costa Rica is beautiful,

去跟他們一起研究火山。

but also because it sits on top of one of these subduction zones.

我當然答應了， 因為哥斯大黎加很美，

We wanted to ask the very specific question:

也因為這個國家座落於 其中一個隱沒帶之上。

Why is it that the carbon dioxide

我們想問這個特定的具體問題：

that comes out of this deeply buried oceanic tectonic plate

為什麽從這個深埋的海洋板塊

is only coming out of the volcanoes?

釋放出來的二氧化碳

Why don't we see it distributed throughout the entire subduction zone?

只從火山口排放出來呢？

Do the microbes have something to do with that?

為什麼不是一整個隱沒帶 都有排放二氧化碳的蹤跡呢？

So this is a picture of me inside Poás Volcano,

微生物跟這件事有什麼關聯嗎？

along with my colleague Donato Giovannelli.

這是我在波阿斯火山裡面的照片，

That lake that we're standing next to is made of pure battery acid.

與我同行的是 同事 Donato Giovannelli。

I know this because we were measuring the pH when this picture was taken.

我們站立處旁邊的湖 完全像是由電池裡的酸所組成。

And at some point while we were working inside the crater,

我會知道是因為我們拍照當時 正在測量其酸鹼值。

I turned to my Costa Rican colleague Carlos Ramírez and I said,

在火山口裡工作的某個時刻，

"Alright, if this thing starts erupting right now,

我轉向我的哥斯大黎加同事 Carlos Ramírez，問他：

what's our exit strategy?"

「好，如果現在這個東西開始噴發，

And he said, "Oh, yeah, great question, it's totally easy.

我們的逃生策略是什麼？」

Just turn around and enjoy the view."

他回答：「喔， 很好的問題，這非常簡單，

(Laughter)

就轉過身欣賞風景吧。」

"Because it will be your last."

（笑聲）

(Laughter)

「因為那會是你的最後一眼。」

And it may sound like he was being overly dramatic,

（笑聲）

but 54 days after I was standing next to that lake,

他的話聽起來似乎過於戲劇化，

this happened.

但自我們站在那湖邊的 54 天之後，

Audience: Oh!

發生了這件事。

Freaking terrifying, right?

觀眾：噢！

(Laughs)

超級可怕，對吧？

This was the biggest eruption this volcano had had in 60-some-odd years,

（笑）

and not long after this video ends,

這是這座火山六十餘年來 最大的一次噴發；

the camera that was taking the video is obliterated

在這影片結束的不久後，

and the entire lake that we had been sampling

拍攝這支影片的攝影機被淹沒；

vaporizes completely.

而我們一直在調查的湖

But I also want to be clear

完全蒸發了。

that we were pretty sure this was not going to happen

但我必須聲明，

on the day that we were actually in the volcano,

我們在火山裡工作的那天，

because Costa Rica monitors its volcanoes very carefully

是非常確定這樣的事情不會發生的，

through the OVSICORI Institute,

因為哥斯大黎加透過 OVISICORI 機構

and we had scientists from that institute with us on that day.

嚴密地監控火山動態，

But the fact that it erupted illustrates perfectly

當時也有幾位該機構的科學家陪同。

that if you want to look for where carbon dioxide gas

而這個它噴發的事實完美地說明了

is coming out of this oceanic plate,

如果你要找尋二氧化碳氣體

then you should look no further than the volcanoes themselves.

是從這個海洋板塊的何處釋放，

But if you go to Costa Rica,

那你應該從火山本身找尋。

you may notice that in addition to these volcanoes

但如果你到哥斯大黎加，

there are tons of cozy little hot springs all over the place.

你可能會注意到除了這些火山之外，

Some of the water in these hot springs is actually bubbling up

還有非常多小型溫泉。

from this deeply buried oceanic plate.

實際上有些溫泉水是從

And our hypothesis was that there should be carbon dioxide

這個深埋的海洋板塊冒上來的。

bubbling up with it,

而我們提出的假說是二氧化碳

but something deep underground was filtering it out.

應該也跟著一起冒上來，

So we spent two weeks driving all around Costa Rica,

但地底下的某個東西把它過濾掉了。

sampling every hot spring we could find --

於是我們花兩週的時間 在哥斯大黎加到處繞，

it was awful, let me tell you.

調查我們所能找到的每一座溫泉——

And then we spent the next two years measuring and analyzing data.

我跟你說，這經驗很糟。

And if you're not a scientist, I'll just let you know that the big discoveries

接著我們花兩年的時間 測量和分析這些資料。

don't really happen when you're at a beautiful hot spring

若你不是科學家，我就直接告訴你，

or on a public stage;

重大的發現通常不會發生在

they happen when you're hunched over a messy computer