In absolute darkness, crushed by the weight of mountains, starved of oxygen, cooked alive, bathed in acid, salt, or radiation.

在絕對的黑暗中，被大山的重量壓垮，缺氧，被活活煮熟，沐浴在酸、鹽或輻射中。

And yet, they live for thousands, perhaps millions of years.

然而，它們卻能存活數千年，甚至數百萬年。

It turns out, this planet is not in space, it's inside the crust of Earth.

原來，這顆行星並不在太空中，而是在地球的地殼裡。

This is the deep biosphere, and we basically learned that it exists yesterday.

這就是深層生物圈，我們基本上昨天就知道了它的存在。

Its volume is at least twice as large as all the Earth's oceans, home to more microbes than the rest of the entire planet.

它的體積至少是地球上所有海洋的兩倍，是比整個地球上其他地方更多微生物的家園。

Their total biomass is more than 20 times greater than all humans, livestock, and animal wildlife.

它們的生物總量是人類、牲畜和野生動物總量的 20 多倍。

Let's descend into this mad, deadly world, where none of the rules we thought mandatory for life apply.

讓我們進入這個瘋狂、致命的世界，在這裡，我們認為生活中必須遵守的規則都不適用。

Going deeper and deeper.

越陷越深

Deep life seems to be everywhere we look, below the oceans, near volcanoes, beneath the glaciers of Antarctica, under any landscape we can imagine, and anywhere we live.

深海生物似乎無處不在，海洋下面、火山附近、南極洲冰川下面、我們能想象到的任何地貌下面，以及我們生活的任何地方。

We'll use a special duck science drill, and start our journey in familiar territory, on land, in the soil, where plants grow and animals roam.

我們將使用一種特殊的鴨子科學鑽頭，在我們熟悉的陸地上、土壤中、植物生長和動物活動的地方開始我們的旅程。

If Earth were an onion, this is the very top of the very top layer.

如果地球是一個洋蔥，這裡就是最頂層的最頂端。

Soil is a lavish four-way partnership of air, water, minerals, and organic matter bathed in endless energy.

土壤是空氣、水、礦物質和有機物四者的完美結合，沐浴著無盡的能量。

Life lives in luxury here.

在這裡，人們過著奢侈的生活。

Plants exploit this paradise, and produce more than 30 times the biomass of all of Earth's animals each year, in a constant cycle of growth and decay.

植物利用這片樂土，在不斷的生長和腐爛循環中，每年產生的生物量是地球上所有動物的 30 多倍。

Only a tiny fraction of the biomass is buried deeper in the ground, supplying juicy resources for almost half a billion years.

只有一小部分生物質被深埋在地下，為近 5 億年的時間提供了豐富的資源。

As we dig deeper, most of the air has been squeezed out, and we cross the water table into a zone saturated with groundwater, rich in minerals, and some organic matter.

隨著挖掘的深入，大部分空氣被擠出，我們越過地下水位，進入一個富含礦物質和一些有機物的地下水飽和區。

Roots from the most ambitious plants reach down here, and the most common inhabitants are scavengers living off decay.

最有野心的植物的根都伸到了這裡，最常見的居民是以腐爛為生的食腐動物。

This layer can be pretty cold, because it's still slowly warming up from the most recent ice age.

這一層可能非常寒冷，因為它仍在從最近的冰河時期慢慢變暖。

We reach bedrock, a foundation of solid rock for all the less solid stuff above, home to fractures filled with water.

我們到達了基岩，基岩是堅硬岩石的基礎，上面有許多不那麼堅硬的東西，裂縫中充滿了水。

It can be exposed to the surface, or buried hundreds of meters below stuff.

它可以暴露在地表，也可以埋藏在數百米深的地下。

Here in the dense bedrock, we're in a weird planet inside the planet, the most thrilling zone of the deep biosphere.

在這塊緻密的基岩中，我們身處地球內部的一個奇異星球，這裡是深層生物圈中最驚心動魄的區域。

As we drill further down, temperatures gradually begin to rise, and soon it gets really hot, and the pressure rises.

隨著我們進一步向下鑽探，溫度逐漸開始上升，很快就變得非常熱，壓力也隨之上升。

Underneath 400 meters of rock, the pressure is similar to the surface of Venus.

在 400 米深的岩石下，壓力與金星表面相似。

We drill faster now, down to 1,000 meters.

我們現在的鑽探速度更快了，可以達到 1000 米。

Deeper than the Burj Khalifa is tall.

比哈利法塔還深，比哈利法塔還高。

It's about 30 degrees Celsius, and there's almost no free oxygen left.

氣溫約為 30 攝氏度，幾乎沒有自由氧氣了。

We continue and finally stop almost 4 kilometers down.

我們繼續前行，終於在近 4 公里處停下。

Above us, pressing, solid rock, weighing tens of thousands of tons, with pressures as intense as at the bottom of the Mariana Trench.

在我們頭頂上，是重達數萬噸的堅硬岩石，壓力之大不亞於馬裡亞納海溝底部。

Down here, it's on average 120 degrees Celsius, even hotter if a magma plume is nearby.

這裡的溫度平均為 120 攝氏度，如果附近有岩漿柱，溫度會更高。

The heat is a leftover from Earth's formation, and from the decay of radioactive elements like thorium and uranium that shower the crust with a constant wave of radioactivity.

這些熱量是地球形成過程中的遺留物，也是釷和鈾等放射性元素衰變產生的，它們給地殼帶來了持續不斷的輻射波。

To make things worse, some rocks are mixed with extreme amounts of salt.

更糟糕的是，有些岩石中還混有大量的鹽。

Hell.

地獄

And yet, life is thriving.

然而，生活卻蒸蒸日上。

Inside rock.

內部搖滾

If we zoom in, we see that solid rock is not actually solid.

如果我們把鏡頭拉近，就會發現堅硬的岩石其實並不堅固。

It's traversed by cracks, voids, and tiny pores.

裂縫、空隙和微小的孔隙遍佈其中。

Sandstone, limestone, or basalt are so porous that up to 40% of their volume is actually empty space.

砂岩、石灰岩或玄武岩的孔隙率很高，多達 40% 的體積實際上是空的。

But even much denser rocks, like granite, can be split open by cracks and fractures.

但即使是花崗岩等密度大得多的岩石，也會被裂縫和斷裂劈開。

We've found a gigantic, planet-spanning system of micro-caves.

我們發現了一個巨大的、橫跨整個星球的微型洞穴系統。

Free real estate, filled with water and hardcore microbes.

自由的土地，充滿了水和頑強的微生物。

And these caves are moving.

這些洞穴在移動。

Just like the atmosphere is constantly mixing air to create weather, down here rocks are mixing to create rock weather.

就像大氣層不斷混合空氣形成天氣一樣，這裡的岩石也不斷混合形成岩石天氣。

Submerged mountain ranges are shifting and ripping, crashing and merging.

被淹沒的山脈在移動、撕裂、碰撞和合並。

Continents smash into each other with the energy of millions of nuclear weapons, but as slow as your fingernails grow.

各大洲以數百萬核武器的能量相互撞擊，但速度就像你的指甲生長一樣緩慢。

Countless tiny and not-so-tiny earthquakes rip open tiny new fissures and passageways, creating new spaces for life and closing others off forever.

無數微小或不太微小的地震撕開了微小的新裂縫和通道，為生命創造了新的空間，也永遠封閉了其他空間。

In this hot, moving pressure cooker, minerals are forged and baked, and organic molecules are created and destroyed.

在這個炙熱、流動的快鍋，壓力鍋裡，礦物被鍛造和烘烤，有機分子被創造和破壞。

An insane menu for anyone brave enough to try to survive down here.

對於任何有勇氣在這裡生存的人來說，這都是一份瘋狂的菜單。

Let's venture into the system of tiny caves and meet some of them.

讓我們冒險進入小洞穴系統，認識其中的一些。

The most extreme living things.

最極端的生物

We think that octillions of microbes live down here, and naturally they are pretty hardcore.

我們認為，這裡生活著數以億計的微生物，它們自然非常頑強。

The doomsday preppers of the underworld.

黑社會的末日預言家。

Some have big, bulky genomes, living entirely on their own, basically forming their own ecosystem.

有些基因組又大又笨重，完全獨立生存，基本上形成了自己的生態系統。

Like the bacterium Dieselphoridus audexviata.

比如 Dieselphoridus audexviata 細菌。

It synthesizes its own food by nibbling carbon or sulfur from the rock and turning it into organic substances.

它通過啃食岩石中的碳或硫，將其轉化為有機物質，從而合成自己的食物。

If the conditions get too extreme, or if there's no food around, it kills itself to survive by forming an endospore.

如果條件過於極端，或者周圍沒有食物，它就會通過形成內生孢子來殺死自己，以求生存。

It divides into a big and a small part and swallows the small part again, forming a cell within a cell.

它分裂成一大一小兩部分，然後又吞下小部分，形成一個細胞中的細胞。

The outer cell then sheds its water and kills itself, leaving the spore to float around, maybe for thousands of years, until it finds a good place to spring to life again.

然後，外層細胞褪去水分並殺死自己，留下孢子四處飄蕩，也許要飄上幾千年，直到它找到一個好地方，再次煥發生機。

Others like some company, like the archaea, with the clunky name Altearchaeum hamiconexum, that have a rare double membrane covered in weird materials that protect them against the extremes.

還有一些人喜歡一些同伴，比如古細菌，它有一個笨拙的名字--Altearchaeum hamiconexum，它有一個罕見的雙層膜，膜上覆蓋著奇怪的材料，可以保護它們免受極端環境的影響。

They shoot out nano-sized grappling hooks to tether themselves and seem to live in cracks and fissures filled with water completely devoid of oxygen, harvest carbon dioxide to create biomass, and may sort of eat hydrogen.

它們射出納米大小的抓鉤來拴住自己，似乎生活在充滿完全沒有氧氣的水的裂縫中，收集二氧化碳來製造生物質，還可能吃氫。

The conditions in the deep biosphere are so harsh that other microbes share the hard work by forming consortia.

深層生物圈的條件非常惡劣，其他微生物通過組成聯合體來分擔艱苦的工作。

They knit themselves together in a biofilm, a very thin sticky net that shields them against the extremes.

它們用生物膜將自己連接在一起，這是一張非常薄的粘性網，可以抵禦極端環境。

They are miniature cells, often with a small genome, but each good at one thing.

它們是微型細胞，通常只有很小的基因組，但各司其職。

One type of microbe eats methane and excretes its electrons.

有一種微生物吃甲烷，並排出甲烷中的電子。

A second type eats these electrons and converts sulfate into sulfite, that's then eaten by a third microbe, and so on.

第二種微生物吃掉這些電子，將硫酸鹽轉化為亞硫酸鹽，然後被第三種微生物吃掉，以此類推。

Some eat iron, others use electrons to turn nitrogen or carbon dioxide into biomass.

有的以鐵為食，有的則利用電子將氮氣或二氧化碳轉化為生物質。

Life down here found ways to use stuff that's poisonous to most animals to make food and energy.

這裡的生命找到了利用對大多數動物有毒的東西來製造食物和能源的方法。

But still life is incredibly hard, and resources and energy are super hard to come by.

但生活依然無比艱辛，資源和能量超級難得。

So the most intense strategy for survival down here is to live forever.

所以，在這裡生存最重要的策略就是長生不老。

Like monks who've taken a vow of poverty, deep microbes consume very little and conserve their energy.

深層微生物就像發過貧苦誓言的僧侶一樣，只消耗極少的能量。

Their metabolism is up to a million times slower than microbes at the surface.

它們的新陳代謝速度比地表微生物慢達一百萬倍。

They had a meal when you were born, and are still digesting it.

它們在你出生時吃了一頓飯，現在還在消化。

For most of their life, they exist in a slow limbo.

在他們生命的大部分時間裡，他們都處於緩慢的邊緣狀態。

Some even slowly cannibalize themselves.

有的甚至會慢慢自相殘殺。

Until a sudden influx of resources arrives by pure chance, and then they spring into action and reproduce.

直到純屬偶然的資源突然湧入，它們才開始行動並繁衍後代。

With this lifestyle, it seems that extreme microbes can live for centuries, maybe even for millions of years.

在這種生活方式下，極端微生物似乎可以存活幾個世紀，甚至幾百萬年。

If they're not hunted to death, of course.

當然，前提是他們沒有被獵殺。

Because kilometers deep in limestone habitats, there seem to be spaces big enough for multicellular predators.

因為在石灰岩棲息地的千米深處，似乎有足夠大的空間供多細胞捕食者生存。

We've found asexual worms, 100 times longer than microbes, hunting and devouring bacteria.

我們發現比微生物長 100 倍的無性蠕蟲正在捕食細菌。

It's not clear if they originated down here, or if many earthquakes opened up fractures for water to carry them into the deep.

目前還不清楚它們是起源於這裡，還是多次地震打開了裂縫，讓水把它們帶入深海。

But there are other fierce predators like rotifers or arthropods in the depths, hunting immortal microbes.

但在深海中還有其他凶猛的捕食者，如輪蟲或節肢動物，它們正在捕食不死的微生物。

We wish we could tell you more insane things about life in the deep biosphere, but there's a problem.

我們希望能告訴你更多關於深層生物圈生命的瘋狂故事，但這是個問題。

We don't know that much yet.

我們還不太清楚。

For one, we can't really get a good look under kilometers of rock.

首先，我們無法看清千米岩石下的情況。

Drilling down could contaminate the samples with microbes from the surface.

向下鑽探可能會使樣本受到地表微生物的汙染。

We've found living ones in deep mines, and brought them into the lab.

我們在深礦井裡發現了活的，並把它們帶到了實驗室。

But it's pretty hard to simulate the conditions they feel comfy in, in boiling hot water, squeezed under mountains, submerged in deadly chemicals, and still see them through a microscope.

但是，要模擬它們在沸騰的熱水中、被擠壓在高山下、浸泡在致命的化學物質中的舒適環境，並且還能通過顯微鏡看到它們，是相當困難的。

And the microbes live so slowly, for so long, that nothing might happen.

而微生物的生存速度如此之慢，時間如此之長，可能什麼都不會發生。

A lot of what we know about them we got from turning them into a slurry and looking at what their genes could do, like breathing nitrogen or eating methane.

我們對它們的很多瞭解，都是通過把它們變成泥漿，然後研究它們的基因能做什麼，比如呼吸氮氣或吃甲烷。

We know that the diversity of life in the deep biosphere must be staggering, and that some of the most hardcore and extreme beings live down there.

我們知道，深層生物圈中的生命多樣性肯定是驚人的，一些最頑強、最極端的生物就生活在那裡。

This is a proper frontier of science, super hard to study, and most of what we know we've learned in just the last 20 years.

這是科學的一個前沿領域，研究起來非常困難，我們所知道的大部分知識都是在過去 20 年裡學到的。

There is so much more undiscovered mystery for us, that could bring us progress in medicine, energy, the climate, and more.

我們還有許多未被發現的奧祕，它們可以為我們帶來醫學、能源、氣候等方面的進步。

Let's end by moving our gaze from the inside to the outside again.

最後，讓我們再次將目光從內部轉向外部。

Since we now know how extremely large the deep biosphere is, and how life down there survives without light, oxygen, sane temperatures, or not being covered in poison, could there be deep biospheres all over the universe?

既然我們現在知道了深層生物圈有多麼巨大，以及那裡的生命是如何在沒有光、氧氣、正常溫度或不被毒物覆蓋的情況下生存下來的，那麼宇宙中會不會到處都有深層生物圈呢？

Maybe all you need is a planet or moon with internal heat or radiation, and a chemical composition that allows microbes to build the parts they need.

也許你所需要的只是一顆具有內熱或輻射的行星或月球，以及一種能讓微生物製造出所需部件的化學成分。

Some scientists suggest there could be 10 of them in the solar system, hiding beneath a seemingly dead and frozen surface.

一些科學家認為，太陽系中可能有 10 個這樣的星球，它們隱藏在看似死寂和冰凍的表面之下。

So as we learn more and more about the life below our feet, we may accidentally learn more about life in the universe.

是以，當我們越來越多地瞭解我們腳下的生命時，我們可能會意外地瞭解更多宇宙中的生命。

We're not going to pretend this time that we got it for our own kids, we just ordered it for fun.

這次我們不會再假裝是為自己的孩子買的，我們只是為了好玩才訂購的。

But we can attest that it makes a great gift for any niece, nephew, gobchard, or other little one in your life.

但我們可以證明，它是送給侄女、侄子、外甥女或其他小夥伴的最佳禮物。

We like KiwiCo because with their new learning club program, they're fostering a mindset of making learning something that's an ongoing exploration, just like we want to.

我們喜歡 KiwiCo，因為他們新推出的學習俱樂部計劃培養了一種思維方式，讓學習成為一種持續的探索，就像我們想要的那樣。

If you want to try out the new KiwiCo clubs, click on the link in the info box, or use the code kurzgesagt to get 50% off your first month of a monthly subscription to KiwiCo.

如果您想體驗新的 KiwiCo 俱樂部，請點擊資訊框中的鏈接，或使用代碼 kurzgesagt，即可享受 KiwiCo 包月套餐首月半價優惠。