About 60% of it is actually a cold and dark region

事實上有 60% 的海域 是既寒冷又黑暗，

known as the deep ocean.

被稱為深海 (deep ocean)。

And it reaches down to 11,000 meters.

它有 11,000 米之深。

Yet, this remote zone is also one of the greatest habitats on Earth,

而這遙遠的海域 卻是地球上最大的生物棲息地之一，

harboring a huge diversity of life,

藏有極繁多的豐富生命，

from giant squids and goblin sharks

有巨型魷魚與哥布林鯊，

to minuscule animals smaller than a millimeter.

也有小於一毫米的微小動物。

How do so many species thrive in this underwater world?

這麼多的物種如何在海底世界茁壯生長？

Over the decades, intrepid scientists have ventured there to find out.

這幾十年來 無畏的科學家到海底冒險找答案。

Traveling down through the water column,

他們向下行駛通過水層，

pressure increases and light begins to wane.

壓力增強並且光線開始減弱。

At 200 meters, photosynthesis stops

海面下 200 米處，光合作用停止了，

and temperature decreases from surface temperatures

而溫度低於海面溫度

by up to 20 degrees Celsius.

20℃ 以上

By 1000 meters, normal sunlight has disappeared altogether.

在 1000 米處 太陽的光線完全無法照到

Without light, life as we know it seems impossible.

我們以為沒有光線 生命就不可能存在

That's why in 1844, the naturalist Edward Forbes

這就是為什麼在 1844 年 博物學家愛德華·福布斯

wrote his Azoic Theory,

寫出他的「無生命理論」(Azoic Theory)

Azoic, meaning without animals.

無生命 (Azoic) 是指沒有動物

Forbes was sure that nothing could survive below 600 meters

福布斯確信 在 600 米以下沒有任何生命，

on account of the lack of light.

因為缺乏光線之故

Of course, the discovery of deep-sea species proved him wrong.

當然，深海物種的發現證明他是錯的

What Forbes failed to take into account is something called marine snow,

福布斯未考慮到一種東西 叫做 海洋雪 (marine snow)

which sounds much nicer than it is.

這名字聽起來比它本身美多了

Marine snow is basically organic matter,

像海洋雪基本上是有機物，

things like particles of dead algae, plants, and animals,

是藻類、植物與動物的殘骸微粒

drifting down into the depths

緩緩沈向海底深處

and acting as food for deep-sea animals.

成為深海動物的食物

Largely thanks to that, abundant life forms exist in the darkness,

主要歸功於海洋雪， 大量生命得以在黑暗中生存，

adapting to a harsh reality where only the weird and wonderful can survive.

牠們適應了 只有奇麗動物能存活的惡劣環境

Fish with cavernous mouths,

有些魚嘴又深又大，

spiky teeth jutting from their jaws,

尖齒從牠們的上下頜突出，

and lamp-like structures protruding from their heads,

並有類似燈狀物從牠們的頭部向外伸出，

like the anglerfish which entices prey with its misleading glow.

像鮟鱇魚， 牠使用迷惑的光來引誘獵物

Several sea creatures have perfected this lightning technique

許多海洋生物已有完善的照明技巧，

known as bioluminescence,

稱為生物發光 (bioluminescence)，

using it to lure prey,

用以引誘獵物，

distract predators,

迷惑掠食者，

or attract mates.

或者吸引配偶

Some creatures use it for camoflauge.

有些動物用它來偽裝

In parts of the water column where only faint blue light filters through,

在某些水層只有淡淡的藍色光可穿透，

animals bioluminesce to match the glow.

動物會發出一樣的淡藍光，

Predators or prey looking up from below

掠食者或獵物從低處仰望這光，

are deceived by this camoflauge,

就會被這偽光所欺騙

unable to see the creatures silhouette.

因此無法看見動物的輪廓

Such otherworldly adaptations also arise from the need to locate

這超凡的演進 也源於捕捉獵物的需求，

and snatch up food before it drifts away.

要在食物漂走前抓住牠

Some sea animals, like jellyfish, comb jellies and salps

有些海洋動物如水母、 櫛水母與樽海鞘

can migrate between depths

可在不同的深度間移居，

partially because their 90% water consistency

部分是因為 牠們 90% 是由水組成，

allows them to withstand immense pressure.

這讓牠們經得起巨大的水壓

But they're the exception.

但牠們是與眾不同的，

Most deep-sea creatures are confined to a narrow range in the water column

絕大多數的深海動物 是被局限在一個狹窄的水層中，

where nutrients are scarce

那地方營養物質稀少，

since the food drifting downwards from the surface

因為食物從海面漂下

rapidly sinks to the sea floor.

迅速沉至海底

Plunging all the way down, we find more exotic creatures.

再一路往下， 我們發現更多奇異的生物

Some take on dwarfism,

有些已侏儒化，

a trait that transforms them into miniature versions of animals

這特質將牠們演化成陸地動物

we see closer to the surface.

的縮小版

It's thought that reduced food availability causes the shrinkage.

一般認為是因缺乏食物，導致牠們縮小

Only a tiny fraction of the food produced at the surface reaches the sea floor,

只有一小部份的食物能從海面到達海底，

so being small gives animals a low energy requirement

但侏儒化的動物能量需求少，

and an adaptive advantage.

這也是個適應的優勢

And yet, the sea is also the land of giants.

海底也是巨獸的世界，

Here, gargantuan squids can reach 18 meters long.

這裡巨大的魷魚長達 18 米，

Isopods scuttle around the sea floor like enormous wood lice.

疾走在海底的等足類動物就像是巨大的木蝨子

There are long-limbed Japanese spider crabs,

這裡也有日本高脚蟹，

and oarfish, whose bodies stretch to 15 meters.

還有皇帶魚，身體可長達 15 米

This trait is known as gigantism, and it's something of a mystery.

這種巨型化趨向的特質還是個謎，

It's thought that high oxygen levels may drive extreme growth in some species,

讓有人認為高含氧量可驅使某些物種極度發育，

while the colder temperatures promote longer life spans,

且較冷的溫度又促使牠們更加長壽，

giving animals the opportunity to grow massive.

動物有機會發育巨大

Many of these exotic sea beasts will never experience sunlight.

許多這些奇異的海獸永遠不會體驗到陽光，

Some will venture up through the water column to feed,

有些海獸會冒險穿越水層覓食

and a few will actually break the waves,

並且有少數甚至會到達海面

reminding us at the surface

提醒了我們

about the incredible survival skills of the ocean's deepest inhabitants.

海底的生物擁有著極妙的生存技能

Humans still have an astounding 95% of the ocean left to explore.

人類仍有驚人的 95% 海洋有待探索，

So those depths remain a great mystery.

因此那些深處仍是一個很大的謎團

What other untold wonders lie far below, and which ones will we discover next?

還有什麼未知的驚奇在這深處下，哪一個又是我們下一次會發現的呢？ (翻譯：Jessica Lee)