生命（2009）

海洋是世上最大的栖地
The ocean. The largest habitat on Earth,
对陆地动物来说 却是无法居住之处
and an inhospitable place for those of us who live on land.
但有十亿年之久
Yet, for a billion years,
海洋是地球唯一有生命的所在
this was the only place on the planet where life existed.
那些早期生物的后代
Today, descendants of those early life forms
活跃至今
continue to thrive.
它们跟鱼类共享大海 但数量超出十倍
They share the sea with fish, but outnumber them by ten to one.
它们没有脊椎
They have no backbones,
而且演化出无数型态
and have evolved into countless different forms.
有些体型惊人 拥有巨大脑部和高度智慧
Some are huge, large-brained and intelligent.
有些极为细小
Others are minuscule,
但建造出世上最大的自然结构
yet build the largest natural structures on the planet.
它们是海洋无脊椎动物 存活在深海的生物
They are marine invertebrates, the creatures of the deep.
它们群居在海洋的每个角落
They have colonised every corner of the ocean,
以出乎意料的
and have a mind-boggling range of solutions
多种方案解决生存难题
to the problem of staying alive.
《深海生物》
海洋绝非完全一致
The ocean is by no means uniform.
深度，温度，阳光和水流的差异
Differences in depth, temperature, sunlight and currents
带来不同的问题
pose particular challenges.
在海面下两公里处的 这些海底热泉
One and a half miles down, these hydrothermal vents
从地壳裂缝喷出 摄氏四百五十度的
spew out super-heated water at 450 degrees Centigrade
超高温热水
from cracks in the Earth's crust.
虽然水压极高
Despite the enormous pressure, the total darkness,
周围一片漆黑 水温更是炙人
and the scaldingly-high temperatures,
所有生命的祖先 或许就在这种地方
the ancestors of all life may have evolved
演化诞生
in a place just like this.
庞贝虫之名
Pompeii worms.
来自它们耐高温存活的能力
So named for their ability to survive volcanic heat.
它们在热泉的邻居，包括蟹类 和两公尺长的巨型管虫
They share the vents with crabs and two-metre-long tube worms.
它们只能在这里生存
They can only survive here
在热泉周围大量繁殖的细菌 能填饱它们的肚子
because they are able to feed on bacteria that thrive around the vents.
这种栖地极为稀有
These colonies are extremely rare.
难怪多数生物 都聚集在靠近海面之处
Not surprisingly, most life thrives
在这里觅食轻松许多
nearer the surface, where feeding is considerably easier.
这是磷虾 类似虾子的细小甲壳动物
These are krill, tiny shrimp-like crustaceans.
磷虾群数量惊人 每立方公尺可高达六万只
Swarms can reach astounding numbers - 60,000 per cubic metre.
它们会在夜间 浮上海面，吃浮游生物
During the night they rise towards the surface to feed on plankton.
在墨西哥的科提兹海
Here, in the Sea of Cortez, off Mexico,
磷虾群吸引各式掠食动物
the swarms attract hunters of all kinds,
从大翅鲸到大批食肉鱼类
from humpback whales to shoals of predatory fish.
有另一个猎人抵达了 它来自深海
Yet another hunter arrives. It's one from the deep.
这是美洲大赤鱿
A Humboldt squid.
身长两公尺 当地人称为
Two metres long, they have a local reputation
吃人怪兽
as man-eaters.
光是一只美洲大赤鱿就够可怕
Alone, they are formidable enough...
但这次来了一群 总共好几百只
..but this is a pack... ..of hundreds.
美洲大赤鱿是很聪明的猎人
They are highly intelligent hunters.
而且视觉敏锐
Their eyesight is exceptional.
它们有强壮触手 吸盘环绕七万个钩子
They have powerful tentacles, suckers ringed with 70,000 hooks
还有能撕裂肌肉的尖锐喙嘴
and a razor-sharp beak for tearing through flesh.
现在鱼群发现自己遭受攻击
Now the fish find that they are under attack
于是集♥合♥起来以保安全
and so group together for safety.
但美洲大赤鱿采取团队合作 把鱼群赶到岩石旁
But the Humboldt squid work as a team, herding the fish against the rocks.
有人认为乌贼变红和变白
It's thought that the squid flash red and white
不只是为了迷惑猎物
not only to confuse their prey,
也是要向同伴发出讯号♥ 指示何时发动攻击
but also to signal to each other when they are about to attack.
美洲大赤鱿的数量正在急速增加
Humboldt squid numbers are growing rapidly.
但它们仍然保持神秘
But they remain mysterious.
跟出现时一样迅速 它们又消失在深海
As fast as they arrived, they disappear back into the deep.
在距离南极一千多公里的
800 miles from the South Pole,
活火山伊里布斯峰山脚下
in the shadow of a smouldering Mount Erebus.
冬季气温是冻寒的零下四十度
Winter temperatures are a punishing minus 40.
这里看似不可能有海洋生物存在
This, perhaps, is the last place you might expect to find marine life.
极地刚开始进入春季
Now it's the beginning of the polar spring,
冰层下的海水 数月来首次有阳光照射
and for the first time in months, light reaches the sea beneath the ice.
这里极度寒冷
It's extremely cold
整年大半时间都是漆黑一片
and completely dark for much of the year,
所以环境很类似深海
so conditions are not unlike those of the deep ocean.
但麦克马多海峡生机蓬勃
Yet, in McMurdo Sound, life flourishes.
这里的动物生长速度极为缓慢
The creatures here grow extremely slowly.
但这表示它们 能长到极大岁数和体型
But that does mean they can reach a great age and great size,
而且它们的数量惊人
and they occur in surprisingly large numbers.
三公尺长的食肉性纽虫
Three-metre-long, carnivorous nemertean worms.
还有红海星和海胆 铺满整片海床
Red sea stars and urchins carpet the sea floor.
巨大的纽虫似乎什么都吃
This monster-worm will eat almost anything
而且不断在海床上搜寻食物
and is constantly scanning the sea floor for food.
动物在这里大批聚集 是因为这个
Animals are swarming here in such numbers because of this...
一只小海豹的尸体
..a dead seal pup.
分量如此丰盛的大餐 十年才会出现一次
Such a great quantity of food may only arrive once in ten years.
但海豹尸体不容易吃
But a seal's body won't be easy to eat.
纽虫有类似鱼叉的吻部
Nemerteans have a snout like a harpoon,
让它们能刺穿尸体的皮肤
that enables them to puncture the skin of the corpse.
红海星就比较辛苦
It's harder work for the sea stars.
它们进食时要从嘴巴吐出胃
They feed by pushing out their stomachs through their mouths.
这只红海星把胃抵在海豹皮肤上
As this sea star presses its stomach against the seal's skin,
然后分泌消化液 溶解海豹的组织
it secretes digestive juices that dissolve the seal's tissue.
但这需要时间
But that takes time.
这支食腐大军 整个夏季都会在这里大吃
These scavengers will feed here throughout the summer,
直到啃光海豹尸体
until all that remains of the seal will be a skeleton,
只剩骨骸
stripped bare.
浅水区仅占海洋世界的一小部
The shallows are only a tiny part of the marine world.
其中九♥成♥都是大海
90% of it is open water.
海流带着生物走过数千公里
Its currents carry life for thousands of miles.
水母正是这种流浪生活的大♥师♥
The masters of this nomadic existence are jellyfish.
漂流在空荡海洋的生活很寂寞
A life spent drifting in the empty ocean could be a lonely one...
但这种水母例外
but not for this jellyfish.
这是海月水母
Aurelia.
它们聚集成群并非意外
Swarms like this are not accidental.
水温和水流都恰好时
These individuals all hatched together
这些水母会一起孵化
when the temperature and currents were just right.
这个时机能确保它们 得以饱餐一顿，赶上浮游生物
Their timing has ensured that they can make the most
在夏季最后一次大量出现
of feeding on a late-summer plankton bloom.
水母没有脑部和血液
Jellyfish have no brain and no blood.
但它们有眼点
But they do have eyespots that enable them
可以分辨明暗
to tell the difference between light and dark.
透过简单的喷水推进
And they can move independently of the current
它们不靠海流也能独♥立♥行动
by a simple form of jet propulsion.
所有水母都有带刺触手 用来捕捉食物
All jellyfish have stinging tentacles with which to catch their food.
它们弹动身体 触手抓住浮游生物
As they pulse their bodies, the tentacles trap plankton,
然后送入位于身体中♥央♥的嘴巴
which is then passed towards their mouth in the centre.
十万只带刺水母群聚
A swarm of 100,000 stinging jellyfish
或许能吓跑掠食动物
might seem a daunting prospect for a predator...
但不包括这只
..but not for this one.
巨大的炒蛋水母
A huge fried egg jellyfish.
它是冷血杀手
It is a killer.
它的武器是覆盖在 触手上的鱼叉状细胞
Its weapons are harpoon-like cells that cover its tentacles.
一接触到受害者
When they come into contact with a victim,
它立刻射出触手
they spear it.
接着炒蛋水母就拖入猎物
The fried egg then hauls in its prey.
少数幸运的海月水母成功逃脱
A few lucky Aurelia do manage to pull themselves free.
但多数受害者都
But for the majority, there is only one outcome...
难逃一死
Death.
一如大多数海洋无脊椎动物
Jellyfish, like a great many marine invertebrates,
水母有脆弱的柔软身体
have soft, vulnerable bodies.
它们有刺细胞保护
They are protected by stinging cells.
但还有其他的防卫方式
But there are other kinds of defence.
就是披上盔甲
Armour plating.
这些是蜘蛛蟹
These are spider crabs.
它们大半辈子都待在深海
They spend most of their lives in deep water.
但每年有一次在澳洲南部外海