- This is our planet's final frontier,
这里是地球上最后的边缘地带 - an inner world where only the most adventurous dare to go.
一个只有最勇敢者 才敢涉足的地底世界 - Beneath our feet are countless miles of cave shafts and passages.
我们脚下有着绵延不绝的洞窟和隧道 - The Cave of Swallows in Mexico,
墨西哥境内的燕子洞 - 400 metres to the bottom,
深达400多米 - deep enough to engulf the Empire State Building.
足以吞没整座帝国大厦 - This is the biggest cave shaft in the world.
这是世界上最大的深洞 - Yet these depths were first explored only two years before man landed on the moon.
然而人类直到登月前两年 才第一次进入这个深渊 - Today caves remain the least explored places on Earth.
今天 洞穴仍是地球上 人类最少涉足的地方 - However, human beings are seldom the first to reach these black, damp places.
但是 人类绝非 这个阴暗潮湿地界的第一位到访者 - Here, live some of the strangest and least-known animals on the planet.
这里住着一些地球上最奇异 和最鲜为人知的动物 - This galaxy of little lights is created by thousands of living creatures.
这“满天星斗”其实是 几千只小动物发出的荧光 - Any animal that lives in a cave has to cope with complete blackness,
住在洞穴里的动物都必须 适应彻底黑暗的环境 - but in New Zealand some have turned this darkness to their advantage.
但是在新西兰 有些动物却能利用黑暗的条件 - A silicon strand is lowered from the ceiling,
一根坚韧的丝从天顶上垂下 - alongside hundreds of others.
边上还有好几百根 - Beautiful though these threads are,
虽然这些丝看起来很漂亮 - they have a sinister purpose.
它们却是阴险的陷阱 - This is a cave glow worm.
这是一种洞穴萤火虫 - To trap its prey it goes fishing with a line of silk.
它利用一根根的丝来诱捕猎物 - The silk comes from glands in the glow worm's mouth
丝产生自萤火虫口中的腺体 - and is loaded with droplets of mucus.
上面缀着一串粘液滴 - Each glow worm produces dozens of these threads.
每条萤火虫都会吐很多根这样的丝 - Once its lines are set,
当一排丝架设完毕后 - the glow worm hangs from a mucus hammock
萤火虫便用粘液将自己悬吊起来 - and waits, like a patient angler.
然后像一位耐心的钓鱼者似的 等待猎物上钩 - But the glow worm doesn't leave everything to chance.
不过 萤火虫并不会听天由命 - That ghostly blue light is the result of a chemical reaction
这些诡异的蓝光是一种化学反应的结果 - taking place inside a special capsule in its tail.
由尾部的一个特殊腔囊产生 - The light literally shines out of its backside.
这些从尾部发散出来的荧光 - It's a lure for attracting prey.
正是用来吸引猎物的诱饵 - Insects seem irresistibly drawn towards the source
昆虫总是禁不住光源的诱惑 - and then get trapped by the sticky lines.
结果就被这些粘乎乎的丝拿住了 - Once stuck,
一旦被粘住 - there is no escape.
根本没有脱逃的机会 - Now it's just a matter of reeling in the line
现在 它只需收起丝线 - and slowly consuming the catch - alive.
然后慢慢吃掉尚且活着的猎物 - By ensnaring the insects that hatch in this cave,
通过诱捕洞穴内羽化的昆虫 - these glow worms have solved the biggest challenge that permanent cave dwellers face -
这些萤火虫成功地解决了 终生穴居动物面临的最大难题 - finding a regular and reliable source of food.
即找到长期而可靠的食物资源 - One kind of rock makes this whole underground world possible -
这些地底世界之所以会存在 都是因为一种岩石 - limestone.
石灰岩 - Most of the world's caves are found within it
世界上大部分洞穴内都存在石灰岩 - and it covers nearly 10 percent of the earth's surface.
它覆盖了地球表面将近10%的面积 - Limestone is composed of minerals derived from marine shells and corals,
石灰岩由海螺和 珊瑚中的矿物沉积后形成 - so although this rocky escarpment in the United States is now hundreds of metres above sea level
所以 尽管美国境内的这座石壁 如今矗立在海平面以上几百米高的地方 - it was actually formed under water.
它实际上却是在水下形成的 - The limestone towers of Vietnam's Ha Long Bay
越南下龙湾的石林 - are a reminder of this link with the sea.
能说明石灰岩与海洋的关系 - Originally, this whole area would have been one solid block of limestone,
起初 这整个地方都是 一整块坚固的石灰岩床 - the base of a coral reef.
珊瑚礁的基座 - In Borneo, rain has sculptured the limestone into extremely sharp-sided pinnacles.
在婆罗洲 雨水已将石灰岩 雕凿成无比尖削的石塔 - But the dissolving power of rainwater has other, much more dramatic effects underground.
不过在地下 雨水的溶解作用 还能产生其它更壮观的效果 - Rivers that flow over limestone often seem to completely disappear.
流经石灰岩的河川 到最后似乎总是无影无踪 - When the water reaches the more resistant bed of limestone
当水流遇到更坚硬的石灰岩床时 - its course is altered.
就会改变路线 - Once underground,
一旦进入地下 - the water takes on a new, more erosive power.
水便有了一股新的、更强的侵蚀力 - During its journey from the surface
在地面上流淌时 - the water absorbed carbon dioxide from the soil
水从土壤中吸收了二氧化碳 - making it mildly acidic.
成为弱酸性 - And over millions of years this acid eats away the limestone
石灰岩经过几百万年的酸蚀作用 - creating a maze of caverns and passages
形成了迷宫般的溶洞和通道 - that sometimes go on for miles.
有的甚至深达数英里 - This is the biggest underground river passage in the world,
这是世界上最大的地下河通道 - so big a jumbo jet could fly through it.
大到可以通过一架大型喷气式客机 - It's Deer Cave, in Borneo.
它就是婆罗洲的鹿洞 - The sheer size of Deer Cave
鹿洞的容量很大 - allows some animals to gather there in huge numbers.
使得大批动物到此聚集 - A staggering 3 million wrinkle-lipped bats live here.
这里住着数量惊人的300万只犬吻蝠 - The bats roost high on the walls and ceilings
这些蝙蝠倒挂在洞壁和天顶上 - where they're well protected from the outside elements
它们在此完全不受外界因素的干扰 - and safe from predators.
还能躲开天敌 - And while they're up here
它们高悬在洞穴上方时 - the bats produce something very important.
会产生一种非常重要的东西 - This hundred metre high mound is made entirely of bat droppings -
这堆100多米高的东西 全都是蝙蝠的排泄物 - guano.
粪便 - Its surface is covered by a thick carpet of cockroaches,
地面上爬满了密密麻麻的蟑螂 - hundreds of thousands of them.
它们的数量无以为计 - Caves are one of the few habitats on Earth not directly powered by sunlight.
洞穴是地球上少数几种 不直接依赖阳光的生态环境之一 - In the absence of plants this food chain is based on a continuous supply of bat droppings.
在缺少植物的情况下 这里的食物链 完全依赖供应不断的蝙蝠粪便 - The cockroaches feed on the guano
蟑螂的食物就是粪便 - and anything that falls into it.
以及任何掉进里面的东西 - The droppings also support other types of cockroaches
粪便也能养活其它种类的蟑螂 - which spend part of their day resting on cave walls.
它们一天大部分时间都呆在洞壁上 - These in turn become food for giant cave centipedes,
这些蟑螂也接连成为了 洞穴大蚰蜒的美餐 - some more than 20 centimetres long.
有的蚰蜒能长到20厘米长 - Bizarrely, there are crabs here, too,
奇怪的是 这里甚至还有螃蟹 - sifting through the droppings for nutrients.
它们从粪便中过滤营养物质 - All these animals spend their entire lives within the cave.
所有这些动物都在洞穴内度过一生 - They're totally dependant on the digested remains of food that's brought here from outside.
它们完全依赖的食物消化残渣 都是来自于外界 - Each evening in just two hours
每天傍晚 只是前后2小时内 - three million bats leave the safety of the cave
300万只蝙蝠一起离开安全的洞穴 - to hunt for insects in the forest outside.
在森林外围捕食昆虫 - But not all will return.
但并非所有的蝙蝠都能返回 - As they leave the cave
蝙蝠离开山洞后 - the stream of bats form a doughnut-shaped ring.
即在空中组成一个面包圈一样的队列 - The wheeling bats seem to confuse a rufus-bellied eagle,
旋绕的蝙蝠群似乎已将 棕腹隼雕弄得晕头转向 - but they must still survive the attacks of other, more specialised, birds of prey.
但它们仍须躲过 其它更专业的猛禽的攻击 - Peregrine falcons and bat hawks are the jetfighters of the bird world.
游隼和蝠鹞是鸟类中的喷气式战斗机 - Good hunting will end as the light fades
天黑后 再高超的捕猎本领 也将无用武之地 - so the bat hawks bolt their catches on the wing
于是蝠鹞一边飞一边吞下猎物 - and fly straight back for more.
然后径直返回继续捕猎 - Any bat separated from the group
任何一只脱离群体的蝙蝠 - becomes a clear and obvious target and is asking for trouble.
立刻成为显眼的目标 很快便遭了殃 - Yet the nightly onslaught has little impact on bat numbers -
然而 每天傍晚的攻击只会 对蝙蝠数量产生很小的影响 - by the morning the vast majority will be back in the safety of the cave.
到了早上 大多数蝙蝠 仍会安然无恙地回到洞中 - Bats are not the only commuters in these Bornean caves.
蝙蝠并非婆罗洲洞窟中的唯一常客 - There's a day shift as well.
这里也有“做日班”的居民 - Returning from hunting in the sunlight
完成白天的狩猎工作后 - these commuters rely on their loud clicks to find their way through the cave passages in total darkness.
这些住客利用它们响亮的叫声 在漆黑一片的洞穴通道内辨别方向 - They're cave swiftlets.
它们就是洞金丝燕 - Like bats they use echolocation to navigate.
和蝙蝠一样 它们也利用回声定位来导航 - We need lights to see what's going on,
我们必须有光才能看清前方的路 - but in the pitch black the swiftlets manage unerringly to locate their individual nesting sites,
但是金丝燕却能在黑暗中 准确无误地到达自己的筑巢点 - which are only a few centimetres across.
而它们的巢窝相隔不过几厘米远 - It's a remarkable skill and one we still do not fully understand.
我们至今仍未能完全了解 这种了不起的本领 - These birds are unusual for another reason.
这些鸟之所以特别还有另外一个原因 - Their little cup-like nests are made entirely from threads of saliva.
它们小巧的杯状燕窝完全由唾液丝筑建 - It takes more than 30 days to complete one.
每个燕窝得花上30多天才能完工 - The nests are very precious objects,
燕窝是非常珍贵的东西 - and not only for the birds.
不仅只是针对这些鸟而言 - For 500 years people have been harvesting the nests of cave swiftlets.
500年来 人们一直采集洞金丝燕的燕窝 - It's a very risky business.
这是一项非常危险的工作 - with virtually no safety equipment
事实上没有任何安全措施 - and using ladders made from forest vines the gatherers climb into the highest reaches of the cave
采集者利用树藤编成的梯子爬到洞穴的最高处 - often more than 60 metres from the floor.
通常高出地面60多米 - The work may be hazardous in the extreme,
这项工作看起来极度危险 - but the rewards are great.
但却能得到丰厚的回报 - The pure white nests of cave swiftlets
洞金丝燕的纯白燕窝 - are the main ingredient of birds' nest soup
是燕窝羹的主要成分 - and gram for gram are worth as much as silver.
每克燕窝的价值堪比白银 - As soon as its nest is removed a bird will immediately build another.
燕窝被摘去后 金丝燕很快又会再吐一个 - So, as long as this valuable harvest is properly controlled,
所以 只要这种利润可观的 采摘行为得到适当控制 - the colonies will continue to flourish.
燕群仍旧可以长盛不衰 - These Bornean caves are among the biggest in the world
婆罗洲的这些洞窟是世界上最大的洞穴 - and they're still getting bigger
它们仍在不断扩大 - as each year rainwater eats away a little more limestone.
因为每年雨水都会侵蚀掉少许石灰岩 - But water in caves doesn't only erode.
可是洞里的水不光只是侵蚀 - It also builds.
它们还能造景 - This water is loaded with dissolved limestone
这些水中含有溶解的碳酸钙 - and when it meets the air in the cave
当它与洞内空气接触时 - some of that is deposited as a mineral -
其中的一些就会沉淀为一种矿物 - calcite.
方解石 - As it builds up
随着它的积累 - so the calcite forms decorations that hang from the ceiling -
方解石形成了悬在洞顶上的装饰物 - stalactites.
钟乳石 - Each drop leaves behind only a miniscule amount of calcite,
每滴水珠只会留下极少量的方解石微粒 - but over time the process can produce some spectacular results.
但随着时间的推移 它们变成了最引人入胜的景观 - If the water seeps though the ceiling quickly,
若是水从洞顶滴落的速度较快 - then the calcite is deposited on the floor of the cave
方解石就会在洞穴地面上沉积 - and that creates stalagmites.
最后形成石笋 - Variations in water flow and the air currents
水流和气流的变化 - produce an infinite variety of forms, but all are created by the same process -
造就了千姿百态的溶洞地形 但它们的形成过程都是一样的 - the slow deposition of dissolved limestone.
都是由水溶碳酸钙缓慢沉淀而来 - And when stalactite meets stalagmite
钟乳石与石笋相遇后 - a column is born.
便形成了石柱 - Structures like these in North America's Carlsbad Cavern
北美洲卡尔斯巴德溶洞中的这些构造 - can take many thousands of years to develop.
经历了数千年的形成过程 - But sometimes the formations in a cave stop growing altogether.
但有时洞穴内的这些活动会完全停止 - These flooded caves in Mexico have remained virtually unchanged for thousands of years.
墨西哥的这些水洞 几千年来几乎保持不变 - Since the last Ice Age they've become cut off from the outside world.
自从上一个冰川期以来 它们便已和外界隔绝 - Yet their impact on life on the surface has been huge.
然而它们对地面上的生物 却有着极其深远的影响 - 500 years ago they supported one of the world's great civilisations
500年前 它们维系着 一个世界上最伟大的文明 - the Maya.
玛雅 - Mexico's Yucatan Peninsula has no rivers, lakes or streams
墨西哥的尤卡坦半岛 没有河流、湖泊和小溪 - so the Maya relied on the cenotes - the flooded entrances to the water-filled caves.
因此玛雅文化完全依赖于沼穴 ——地下水洞的入口 - These flooded shafts are the region's only source of open fresh water.
这些水潭是整个地区 唯一的露天淡水资源 - The cenotes are, in effect, gigantic fresh water wells.
沼穴于是成了巨大的淡水井 - Away from the life-giving rays of sunshine
这里远离给予生命的阳光 - one might not expect to find plants.
似乎不太可能会有植物 - But in the darkness of the cave tunnels
但是在黑暗的洞穴通道内 - roots of giant tropical trees have pushed their way through cracks in the limestone
大型热带树木的根系 却已穿透石灰岩裂缝 - to reach the flooded caverns.
伸入到水洞之中 - Without this water
如果没有这些水 - the Yucatan's forest could not grow so luxuriantly.
尤卡坦半岛的森林不可能长得如此茂盛 - The Maya knew that their lives depended on this water,
玛雅人固然知道 它们的生活离不开这些水 - but it's only with the help of today's technology
但只有借助现代科技 - that we've come to appreciate the full significance and scale of these flooded passageways.
我们才能完全了解 这些地下水道的重要性及其规模 - So far, more than 350 miles of underwater galleries in the Yucatan have been mapped,
人们迄今为止已绘制了350英里的 尤卡坦半岛地下水系图 - but still nobody yet knows the true extend of this subterranean waterworld.
但仍旧无人知晓 这个地下水世界究竟有多大 - And with good reason.
以及它形成的原因 - Underwater caving is notoriously dangerous.
地下水洞是出了名的危险 - When the nearest exit may be hundreds of metres or more away,
最近的出口可能远在 几百米之外或者更远的地方 - running out of air down here would be fatal.
在这里 耗尽氧气将是致命的 - To avoid getting lost
为了避免迷路 - divers carry with them a spool of string.
潜水员必须随身携带一捆轴线 - It becomes their lifeline -
这成了它们的救生索 - literally.
绝对如此 - The string also doubles as a measuring tape -
这根线同时也是测量尺 - a technique that has been used here, in Mexico, to chart the largest underwater cave in the world -
在墨西哥的这个地方 这种科技被用来 测绘世界上最大的地下水洞 - all 100 miles of it.
全长达100多英里 - Cave exploration often requires you to push yourself through narrow gaps in the rock.
洞穴探险需要不时挤过 一些狭窄的岩石缝隙 - Cavers call such places 'squeezes.'
洞穴专家称之为“瓶颈” - The tighter the squeeze,
“瓶颈”越是狭窄 - the greater the chance of damaging some vital life-support system.
便越有可能损坏一些重要的生存设备 - In these conditions a diver could easily become disorientated
在这种情况下 潜水员很容易迷失方向 - and that could be fatal.
而这将导致送命 - The flooded caverns can play tricks on you in other ways.
地下水洞还会以别的方式戏弄你 - What seems like air,
这看上去像是空气 - isn't.
不对 - It's just another kind of water.
它只是另一种水 - This is a halocline -
这里是盐跃层 - a meeting of fresh and salt water.
淡水与咸水的交汇处 - Fresh water from the jungle flows over the heavier salt water from the sea.
咸水来自海洋 比重较重 来自丛林的淡水在其上方流动 - The saltwater layer is extremely low in oxygen
咸水层的含氧量很低 - making it a particularly difficult place for animals to live.
对动物而言是极为困难的生境 - Yet some have managed it,
但有些动物却能在此生存 - like the remiped, one of the most ancient of all living crustaceans.
例如桨足虫——一种最古老的甲壳动物 - The Maya understood the importance of the cenotes,
玛雅人知道沼穴的重要性 - but they could never have known that these flooded passageways were actually the beginning of subterranean rivers,
但他们从不知道这些水下通道 其实是地下河的入口 - all of which eventually flow out to the sea.
它们最终都流向大海 - Salt water, unlike fresh water, does not erode limestone,
咸水与淡水不同 不会溶解石灰岩 - so most sea caves are created by the mechanical pounding of the waves.
所以大部分海洋洞窟 是在海浪的机械冲击下形成的 - The rocky outcrops of New Zealand's Poor Knight Islands are riddled with sea caves
新西兰坡·骑士岛的 岩礁下布满了海蚀洞 - and just like those in Borneo
与婆罗洲的洞窟一样 - they have become important shelters for many species.
它们也成了许多动物的重要庇护所 - After a day feeding in the open water
经过一天开放水域的觅食之后 - vast shoals of demoiselle fish return to the caves,
大群雀鲷返回到洞窟中 - which they use as a refuge from predators.
这里是它们躲避天敌的地方 - For these fish the caves are a night time retreat,
对于这些鱼来说 洞穴是理想的过夜场所 - but they're not the only commuters in here.
但它们并非这里的唯一住客 - There are other fish working to a different schedule.
这里还有其它 按照不同日程表生活的鱼 - The bigeyes are the equivalent of bats.
大眼鲷相当于蝙蝠 - Night feeders leave the cave each evening.
它们每天晚上出洞觅食 - And like all cave commuters
和所有洞穴动物一样 - they are most vulnerable at the scheduled time of departure.
它们在出发阶段最容易遭受攻击 - A bottleneck funnels these exiting bats into dense concentrations
当大群蝙蝠密集地通过瓶颈出口时 - attracting the attention of others.
很容易引起其它动物的注意 - The bats can detect the snakes using echolocation,
蝙蝠能利用回声定位觉察到蛇 - but the snakes are literally in the dark -
而蛇则完全处于黑暗之中 - they can see nothing.
它们看不见任何东西 - The strikes seem to be largely hit-and-miss,
这种攻击更像是在碰运气 - but the snakes have a secret weapon.
不过蛇也有自己的秘密武器 - They can actually sense each bat flying past.
它们实际上能感觉到 每一只飞过的蝙蝠 - Receptors in the snake's head pick up the heat given off by the flying bats,
位于头部的“热眼”能觉察到 飞行中的蝙蝠散发出的热量 - as this thermal image shows.
正如这幅热影像所示 - To the snakes the bats are apparently glowing
每一只蝙蝠在蛇“眼”前都是活灵活现 - and this gives them something to aim at.
这也给了它们瞄准目标的机会 - This is the price that these cave commuters must pay
这是洞栖动物必须付出的代价 - for their daytime sanctuary on the ground.
以换取它们白天在陆地上的庇护 - Small wonder then that there are other cave dwellers that stay put.
难怪其它洞穴生物 要终生居住在洞穴中 - Many caves are like islands -
很多洞穴都和岛屿一样 - cut off from the outside world and from other caves.
与外界及其它洞穴隔绝 - This isolation has resulted in the evolution of some various strange creatures.
这种孤立环境导致进化产生 各种各样奇怪的生物 - They are the cave specialists -
它们都是洞穴专家 - troglodytes, animals that never emerge from the caves or see daylight.
穴居动物——从不出洞并且 永远不见天日的动物 - These troglodytes from Thailand
泰国的这些穴居动物 - are possibly the most specialised creatures on Earth
可能是地球上最奇特的动物 - for they live only in cave waterfalls.
因为它们只生活在洞穴瀑布中 - The entire population of these cave angel fish
世界上所有的洞穴天使鱼 - seems to be restricted to just two small caves.
可能只存在于两个较小的洞穴中 - It's the same story with other troglodytes.
其它穴居动物也是同样的情况 - There may well be less than a hundred Texas cave salamanders in the wild.
世界上可能只有不到100只 野生洞栖童态河溪螈 - And the Belizean white crab is another creature that is unique to just one cave system.
而伯利兹白蟹是另一个 洞穴生态系统中的特有物种 - Living in perpetual darkness
由于一直生活在黑暗之中 - they have all not only lost the pigment in their skin,
它们不仅失去了皮肤色素 - but also their eyes.
眼睛也退化了 - It takes thousands of generations for eyes to be lost,
眼睛的退化需要经历数千代的演变 - so these species must have been isolated for a very long time.
所以这些物种必定 与世隔绝了相当长的一段时间 - But the blind salamander has other highly developed sensory organs.
不过这些瞎眼的蝾螈 进化出了其它发达的感觉器官 - Receptors in their skin detect minute movements in the water made by its prey.
皮肤上的探测器能觉察到 猎物引起的最微小的水流变化 - External gills help it to breathe in water that is particularly low in oxygen.
外生的鳃帮助它们 在极度缺氧的水中呼吸 - The cave angel fish feed on bacteria in the fast flowing water
洞穴天使鱼以急流中的细菌为食 - keeping their grip with microscopic hooks on their fins.
它们用鳍上的小钩紧紧抓住岩壁 - Food is often in short supply
食物总是很紧缺 - and troglodytes like the crab
像螃蟹这样的穴居动物 - have to survive on whatever washes into the cave from outside.
必须得吃任何从外边冲进洞内的东西 - The salamander might not encounter food for several months,
童态河溪螈可能 已有几个月没有吃东西了 - so when something does come along
所以只要眼前有食物出现 - it can't afford to miss it.
它绝对不会放过 - It's astonishing that these extraordinary cave dwellers manage to survive at all.
这些奇异的洞栖生物能如此成功地生存 的确令人称奇 - But one cave is so inhospitable
可是有一个洞穴的环境过于险恶 - that one would not expect it to contain any life whatsoever.
不管什么生物似乎都不可能在那里生存 - The water flowing out of the Villa Luz cave in Mexico
从墨西哥露兹别墅山洞流出来的水 - is actually coloured white with sulphuric acid.
竟然被硫酸染成了白色 - Explorers entering this dangerous cave
探险家们进入这个危险的山洞时 - must wear respirators and carry monitors.
必须戴上防毒面具 并携带通话器 - Poisonous gases rise to fatal levels so quickly
有毒气体很快就会达到致命的程度 - that an early warning system is essential.
所以即时预警设备是最重要的 - Bats survive by staying close to the skylights,
蝙蝠之所以能生存是因为 它们始终呆在天窗附近 - but venturing deep into the cave is very dangerous indeed.
但是深入洞穴必然极度危险 - The source of these toxic fumes lies several miles below.
这些毒气的源头位于地下几英里处 - Hydrogen sulphide gas bubbles up from oil deposits in the earth's crust.
硫化氢气体从地壳内的油气储层中溢出 - It mixes with oxygen and the water,
与水中的氧发生化合反应 - and forms sulphuric acid.
产生了硫酸 - These are not the sort of conditions in which you would expect to find fish,
鱼类似乎不太可能生活在这种环境中 - yet these cave mollies seem to thrive
然而这些洞栖帆鳍? 看上去却是悠然自得 - despite the acid and the low levels of oxygen.
尽管这里是酸性低含氧量环境 - There is, in fact, more life here than anyone would think possible,
事实上 这里的生物数量 远比人们预料的更多 - but the biggest surprise is something altogether more bizarre.
不过更大的惊奇莫过于 那些更奇怪的东西 - These strange stalactite-like formations are known, rather appropriately, as snotites,
这些奇特的钟乳石状的结构 确切地说 叫做“鼻涕石” - the drops dripping from the ends are sulphuric acid,
其末端滴落的液滴就是硫酸 - strong enough to burn skin.
酸性强到足以腐蚀皮肤 - The snotites are, in fact, vast colonies of bacteria,
“鼻涕石”其实是大型菌落 - capable of going a centimetre a day.
每天能长长1厘米 - In this world without sunlight
在这个没有阳光的世界里 - these bacteria extract energy from the hydrogen sulphide gas.
这些细菌只能从硫化氢气体中吸收能量 - Bacteria like these are known as extremofile
像这样的细菌被称为嗜极生物 - because of their ability to survive in such extreme conditions.
因为它们能在这种极端环境中生存 - And these extremofiles play another important role in this cave.
这些嗜极生物还在这个洞中 扮演着另一个非常重要的角色 - Surprisingly, they are the basis of a food chain
令人吃惊的是 它们竟然是食物链中的第一环 - which supports, amongst other creatures, the larvae of these midges.
用以养活其它生物 例如这些蚋的幼虫 - Villa Luz's ecosystem was certainly very remarkable,
露兹别墅山洞的生态系统的确非同寻常 - but cave explorers were soon to make an even more astonishing discovery.
但是洞穴探险家们 很快又有了更惊人的发现 - Beneath this arid landscape lies a subterranean wonderland.
谁能想到在这些贫瘠的土地下 有一处地下仙境 - Without water one might not expect to find any caves,
没有水的地方似乎不可能有洞穴 - but beneath these rolling desert slopes in the United States
但是在美国这些荒凉起伏的山崖之下 - lies one of the longest, deepest and most surprising caves in the world.
存在着一座世界上最长、最深 也最令人惊奇的洞穴 - Its secrets remained unknown until 1986,
它的秘密直到1986年才被人们发现 - when cavers dug through several metres of loose rock
洞穴专家们在松散的岩层中 挖出了一条几十米深的通道 - to the bottom of this pit.
直达这个深渊的底部 - They named the cave 'Lechuguilla'
他们把这个洞命名为“龙舌兰洞” - and since this discovery more than 120 miles of passageways have been mapped.
自从那次发现之后 迄今已测绘了120多英里的地道 - When the first explorers descended,
第一批探险家进入这个洞后 - no-one guessed at the sheer size of this cave.
没有一个人能预料到它竟然有这么大 - But even that was not going to be the biggest surprise.
即便如此 这也不能算是最大的惊奇 - Little did they realise that Lechuguilla would soon be regarded by cavers the world over as the most beautiful of all caves.
不久他们便意识到龙舌兰洞很快就会 被全世界的洞穴专家公认为地球上最美丽的洞穴 - They were about to discover some of the most exquisite formations ever seen underground.
因为他们发现了一些 地底世界中最精美的构造 - The walls were covered with the most delicate and fragile crystals.
石壁上布满了光洁美丽的脆弱结晶 - Many of these crystals were made of gypsum,
许多结晶都是由石膏组成 - a mineral that comes from limestone.
一种硫酸钙沉积而来的矿物 - And there was mile after mile of them.
它们绵延不绝 - Water is the creator of most caves,
水是大部分洞穴的建造者 - but, unlike all other limestone caves,
但是 和其它石灰岩溶洞不同的是 - Lechuguilla's rock had not been eaten away by running rainwater.
龙舌兰洞中的岩石并非被流水侵蚀 - Something else was responsible.
而是因为其它的作用力 - The only water Lechuguilla has are these wonderfully still clear pools.
龙舌兰洞中唯一的水 来自这些平静清澈的水塘 - As the explorers went deeper into the cave,
随着探险家们深入洞穴 - they came across whole galleries filled with the most unusual formations,
他们发现了成片叹为观止的地貌 - like these 5-metre cones, frosted with the most delicate crystals.
例如这些5米高的石锥 上面布满了雪霜一样的松脆结晶 - It was Lechuguilla's gypsum crystals
龙舌兰洞的石膏结晶群 - that made scientists question how these caverns were formed.
使科学家们产生了 这个巨洞如何形成的疑问 - They discovered that Lechuguilla's limestone had actually been eaten away by sulphuric acid,
他们发现龙舌兰洞的石灰岩 实际上是被硫酸侵蚀的 - cutting through literally miles of limestone.
凿穿了差不多数英里的石灰岩 - And when sulphuric acid dissolves limestone
硫酸在溶解石灰岩的同时 - it leaves behind gypsum,
也留下了石膏 - the basis of Lechuguilla's remarkable formations.
它们最终形成了龙舌兰洞的奇景 - And there was one set,
这里有一组景观 - more than a mile from the surface,
位于地表之下1英里多的地方 - that almost defied belief.
美得简直无法令人相信 - The Chandelier Ballroom was the ultimate discovery.
“灯饰大厅”是最后被发现的厅洞 - With its six-metre long crystals
这里尽是6米多长的结晶群 - it's surely the most bizarre cave chamber in the world.
它可以说是世界上最奇异的厅洞 - And the walls had one further surprise.
而石壁上还有更惊人的发现 - Extremofile bacteria were found to be feeding on the rock itself.
嗜极细菌在岩壁上自我生长 - The discovery of life that exists without drawing any of its energy from the sun
生命彻底脱离太阳能量 却依然生存的现象 - shows us once again how complex and surprising the underground world can be.
再一次向我们展示了地底世界 是多么的复杂和惊人 - Each year explorers chart over a hundred miles of new cave passages.
每年 探险家们都会测绘 上百英里新的洞穴通道 - But with half the world's limestone still to be explored,
但世界上仍有一半石灰岩洞尚未被开发 - who knows how many Lechuguillas are still waiting to be discovered?
谁知道还会有多少个龙舌兰洞 等着人们去发现呢 - [The End]
[本集结束]
行星地球 第一季 第四集 Planet Earth S01E04 洞穴
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