大裂谷：美丽的非洲心脏（2010）

大裂谷起伏的山峦下面
Beneath the Great Rift's rolling hills,
多孔火山岩下渗透的地下水
porous volcanic rocks channel water deep underground,
有时绵延数英里
sometimes for many miles.
最后，地下水在春天渗出
The subterranean water eventually pops out as a spring,
滋养着清澈溪流和湖泊绿洲
like this one at Mzima in southern Kenya,
比如肯尼亚南部的姆济马
feeding an oasis of crystal-clear streams and lakes.
因为当地庞大的地下水库
Because it's supplied from a large underground reservoir,
姆济马火山在春天有源源不断地溪水流入
a volcanic spring like Mzima continues to flow
即使是在旱季的高峰期...
even at the height of the dry season...
...全年为野生动物提供生存天堂
..providing a year-round haven for wildlife.
鼻息声
SNORTS
而大裂谷独特的地质
And the Rift's unique geology
产生了另一种水源
has produced another kind of water supply
这里同样没有旱灾
that's equally immune from drought.
直线下降6英里深
Plunging six miles deep,
坦噶尼喀湖是非洲最大的天然水库
Lake Tanganyika is Africa's greatest natural reservoir.
它容纳着30万亿公升水...
It contains 30 trillion litres of water...
...并向西部裂谷延伸了400英里
..and stretches 400 miles along the Western Rift Valley.
它的姊妹湖，马拉维湖，也有一个类似的轮廓
Its sister lake, Malawi, has a similar profile.
马拉维湖有奇特而五彩缤纷的慈鲷而闻名
Lake Malawi is famous for its extraordinary diversity of cichlids.
里面有1000多个品种的慈鲷是地球上绝无仅有的
More than a thousand unique varieties found nowhere else on Earth.
所有人都认为，有少数品种的数量正在下降
All are believed to be descended from just a handful of species
它们演变出的形状，颜色和行为令人眼花缭乱
which have evolved a dazzling array of shapes, colours and behaviours.
这一进化大爆♥炸♥的关键
The key to this explosion of evolution
在于慈鲷非凡的繁殖能力
lies in the cichlids' peculiar breeding behaviour.
大多数鱼都会到开阔水域产卵
Unlike most fish, which release their eggs into open water,
慈鲷非常仔细的照顾幼鱼
cichlids take great care of their young.
有些沙底物种建造了外形酷似火山的巢
Some sandy bottom species build volcano-shaped nests
它们在那里繁殖
where the male courts his female,
然后看守它的幼鱼
then guards her brood
直到它们长大到有能力可以照顾自己
until they have grown big enough to look after themselves.
有一种小慈鲷和它们的母亲有着很古怪的关系
Other baby cichlids have a truly bizarre relationship with their mother.
当遇到危险时，它们都躲进了母亲的嘴里
When threatened, they take shelter in her mouth.
然后母鱼便带着它们,等到风平浪静时
She then carries them around, waiting until the coast is clear
在开阔水域才会放它们出来
before releasing them back into open water.
这种细心地保护
Such intensive parenting
让慈鲷往往在一个地方终其一生
means cichlids often stay in one spot throughout their lives,
这将形成独特的本地物种和天然庇护所
forming inbred communities which turn into unique local species.
也就解释了为什么马拉维湖是有这么多不同的慈鲷
And that explains why Lake Malawi is filled with so many different cichlids.
对于小的鱼，岩石湖边际是一个危险地方
For little fish, the rocky lake margin is a dangerous place.
一个非洲斑颈水獭家庭
A family group of African spot-necked otters
开始在沿岸一带猎食
sets out to hunt along the shoreline.
每当夜幕降临，湖里的鱼就面临着最大的敌人
As night falls, the lake's fish face a formidable enemy.
一群觅食的鲯鳅，它们长得像鲨鱼，长1.5米
Pack-hunting nyanda fish, 1.5m long, behave like sharks,
种带电的鱼类在自己身体周围创造一个电场
using an electrical sense
它们通过探测电场的变化情况来寻找躲藏在岩石后的鱼
to home in on the life signs of smaller fish hiding among the rocks.
它们甚至有用电♥信♥♥号♥♥传递信息
It's thought they can even communicate with electrical signals,
一起在黑暗中觅食
to synchronise their feeding in the dark.
对于它们的猎物，逃生的机会不大
For their prey, there's little chance of escape.
更远一些的湖滨
Further from shore,
马拉维湖像是陷入了永久的黑暗
Lake Malawi plummets into permanent darkness
超出了人类潜水范围
beyond the reach of human divers.
直到现在，还没有人见识过那里的环境
Until now, no-one has seen what lives down there.
远程控制器，手持摄像机, 灯和鱼饵
A remote-controlled sub, armed with camera, lights and fish bait,
让我们第一次看见了下面到底有什么
provides the first glimpse of what lies below.
水下100多米地方，鱼饵吸引来深水慈鲷...
Over 100m down, the fish bait attracts deepwater cichlids...
...但是它们的牙齿不能咬穿鱼饵盔甲般的皮肤
..but their teeth can't get through its armoured skin.
食物的气味还吸引了 —湖蟹
Attracted by the smell of food - a lake crab.
在监控画面里，一条倒游鲶
In the background, a short-bodied synodontis catfish
用它的胡须试探诱饵
uses its whiskers to investigate the bait.
现在轮到bathy clariao(一种深水鲶鱼),
Now it's the turn of bathy clarias,
第一次在这里拍摄到了深水鲶鱼
a deepwater catfish, filmed here for the first time.
在这个深度，鱼饵变成了它们难得一见的美食
At this depth, the fish bait provides a rare treat.
鲶鱼疯狂的进食
The catfish is frantic to feed.
由于沿线湖床上的死鱼散播的气味
As the smell of dead fish spreads along the lake bed,
越来越多的螃蟹被吸引到了这里
more crabs are drawn to the scene.
最终，螃蟹们团结了起来，形成了满是腿和爪的封锁线...
Eventually the crabs close ranks, forming a barricade of legs and claws...
..将鱼饵占为己有
..claiming the fish exclusively for themselves.
谁曾想到，大裂谷湖泊的深处
Who would have guessed that the Great Rift's lake depths
会被螃蟹统治呢
are ruled by scuttling crustaceans?
还有其他的生物生活在这里吗
And what else could be down here?
鲶鱼和螃蟹只是大裂谷淡水世界最常见的物种而已
Catfish and crabs are only minor players in the Rift's freshwater economy.
但马拉维湖还有另一种很重要的居民
But there's another resident of Lake Malawi that plays a major role
它决定着整个地区的命运
in the fortunes of the entire region.
北部的冬季期间，在新月升起的那几天
A few days after each new moon during the northern winter months,
像龙♥卷♥风♥一样奇怪的云在湖面上凝结
strange tornado-like clouds condense over the lake.
这种现象大多发生在风平浪静的时候
The phenomenon happens during periods of calm weather,
形成的云旋涡高达几百米
allowing the fragile spirals to build hundreds of metres high.
它们由微小的湖蝇组成
They consist of vast numbers of tiny midges.
那里的随意一朵湖蠓云
There may be more midges in a single cloud
可能比地球上人类的数量还要多
than there are humans on earth.
所有的湖蝇都只有一个目的，那就是繁殖
All are driven by a single purpose - to breed.
它们忘情的跳着舞蹈，云朵却已经慢慢的飘向了陆地
Absorbed in their dance, the midge clouds drift towards land.
嗡嗡声
HIGH-PITCHED BUZZING
数小时之后，沿岸植物变成了这些湖蝇的栖身之地
Plants along the shore provide a resting place after hours of constant flight.
但是植物里隐藏着敌人
But the vegetation harbours enemies.
蜘蛛一直生活在湖泊岸边众多生物集聚的丛林
Spiders live along the lake margins in huge mixed colonies.
到处都是蜘蛛设置的蛛网陷阱
Some trap the midges in sticky webs.
静静地等候猎物出现
Others use goggle eyes to stalk their quarry,
然后像小老虎一样猛扑过去
pouncing like miniature tigers.
尽管前进的路上有无数的伤亡
In spite of countless casualties along the way,
但最终大多数湖蝇都回到了湖里
the majority of the insects eventually return to the lake
完成了它们的使命
to fulfil their destiny.
雌湖蝇趴在湖面产卵
The females lay their eggs on the water surface.
然后，它们也逐一死去
Then they die.
慢慢下沉的卵...
The eggs sink...
..和已经孵化的半透明的幼虫 -
..and hatch into translucent aquatic larvae -
变成了湖面上专门猎捕微小浮游生物的天生杀手
tiny predators which specialise in feeding on lake plankton.
因富含火山岩中的矿物质
Enriched with minerals from the surrounding volcanic rocks,
马拉维湖滋养着着丰富的浮游生物
Lake Malawi's waters support an abundance of plankton,
这就是为什么湖蝇在这里会如此繁盛
which is why the midges are here in such spectacular numbers.
但故事并未就此结束
But the story doesn't end here.
马湖沙丁鱼贪婪的猎捕湖蝇及其幼虫
Sardine-like usipa are voracious predators of midges.
而这些不起眼的小鱼
And these unassuming little fish
就是这个惊人的食物链中重要的最后一个环节
are the key to one last link in this amazing food chain.
湖面上，渔民们将独木舟放入湖中
All around the lake, fishermen are launching their dugouts
吸引夜间的湖蝇
in anticipation of a nocturnal uprising.
马湖沙丁鱼在月亮初升之时开始觅食
Usipa fishing takes place at the new moon,
灯是湖面上唯一的光源
when lamps are the only source of light on the lake.
说方言
MEN CONVERSE IN LOCAL LANGUAGE
渔网在两条大船之间被绕成了一个圈
Divided between the two larger boats, the net is paid out in a circle.
在中间, 灯光像吸引着湖蠓
At the centre, the lamp-bearing boats draw up the fish to the surface
诱惑沙丁鱼上来捕食
like moths to a flame.
随着绳子在网底被拉拢，渔网变成了一个密封的陷阱
With the bottom rope pulled tight, the trap is sealed.
每次只能拉上来几公斤鱼
Each haul may yield just a few kilos of sardines,
但渔民会通宵捕鱼，直到黎明时分才上岸
but the fishermen will land over a dozen catches before dawn.
讲方言
MEN CONVERSE IN LOCAL LANGUAGE
在一个小岛附近的渔场
On an island close to the fishing grounds,
渔民们吃了点早餐后就回家了
the fishermen grab some breakfast before heading for home.
突突声
ENGINE REVS
尼罗河巨蜥是非洲最大的蜥蜴，长2米
At 2m long, the Nile monitor is Africa's largest lizard -
有着锐利爪子和强劲下颌的善于伏击的捕食者
an ambush predator armed with raking claws and powerful jaws.
但现在有免费的食物，有必要去打猎吗
But why bother to hunt when there's free food on offer?
嘶嘶声
HISSES FIERCELY
渔船渐渐靠近海岸，聚集的人群正在迎接他们
As the fishing boats near the shore, a crowd gathers to meet them.
讲方言
PEOPLE CONVERSE IN LOCAL LANGUAGE
马拉维的气候很炎热，很难把新鲜的鱼送到遥远的市场
In Malawi's hot climate, it's hard to get fresh fish to distant markets,
所以大多数都晒成了鱼干
so most is spread out to dry in the sun.
这样，鱼可以保存数周甚至数月
Like this, they will keep for weeks or even months.
令人惊讶的是，这些微小的沙丁鱼为沿岸国家
Astonishingly, these tiny usipa provide essential protein