004 探索洞穴

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Will sat at his desk, staring at a picture in his textbook

威尔坐在书桌前，盯着课本里的一张图。

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" How can huge holes just appear underground? I don't understand," he thought

“地底下怎么会出现这么大的洞？搞不懂。”他想。

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He noticed it was already ten o'clock." I'm so tired I can't even think anymore!

他注意到已经十点了。“我累得没法再想了！

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I'll finish this report tomorrow morning," he decided and climbed into bed. Within minutes he was asleep

明天早上再把这个报告写完吧。”他决定后，爬上床，没几分钟就睡着了。

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Will woke up shivering. He opened his eyes but saw nothing — just blackness!

威尔冻得发抖，醒了过来。他睁开眼睛，却什么也看不见——只有一片漆黑！

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It was eerily quiet, except for a constant dripping

四下寂静得诡异，只有持续不断的滴水声。

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Then QT's screen lit up, and Will realized he wasn't in his room anymore

这时，QT的屏幕亮了起来，威尔才意识到他不在自己的房间里了。

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" You are in Mammoth Cave, in Kentucky," QT said

“你在肯塔基州的猛犸洞里。”QT说。

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" This is the world's longest cave system. People have explored almost six hundred kilometers of tunnels and caverns so far!"

“这是世界上最长的洞穴系统。到目前为止，人们已经探索了近六百公里的通道和洞室！”

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" I wouldn't want to get lost down here," Will murmured. Then, trying to be brave, he asked," How are caves formed, anyway?"

“我可不想在这里迷路。”威尔咕哝着。接着，他努力表现得勇敢，问道：“洞穴到底是怎么形成的呢？”

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" Well, there are many types of caves. I'll show you," QT said and projected an image of a cliff on the cave wall

“洞穴有很多种，我来展示给你看。”QT说着，在洞壁上投射出一幅悬崖的图像。

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" Sea caves are made by waves beating on rock for a very long time, hundreds and thousands of years

“海蚀洞是由海浪长时间拍打岩石形成的，要经过成百上千年。

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The wind can also carve out caves. You often see these in deserts. There are caves in lava tubes too

风也能雕琢出洞穴，这种在沙漠里很常见。熔岩管里也会有洞穴。

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When lava is flowing from a volcano, the top gets cool first and hardens, but the hot lava inside flows right out, leaving a cave behind

火山喷出的熔岩流，顶部先冷却变硬，但里面滚烫的熔岩继续流走，就留下一个洞穴。

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Sometimes caves are even formed in glaciers when water flows through the cracks, making them into big holes."

有时，冰川里甚至也会形成洞穴，当水流过冰裂缝，把它们冲成大洞。”

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Will looked at the fantastic formations on the ceiling." This cave doesn't look like any of those."

威尔看着洞顶上奇妙的构造，说道：“这个洞穴看起来不像以上任何一种。”

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" We are in a solution cave, the most common type

“我们正身处一个溶洞里，这是最常见的一种洞穴。

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This kind of cave is formed when water trickles through a layer of limestone in the ground to the water table, the level where our groundwater starts."

这种洞穴是这样形成的：水渗过地下的一层石灰岩，一直到达地下水位，也就是地下水开始的地方。”

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Will was amazed." Water made this cave?"

威尔很惊讶。“水造出了这个洞穴？”

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" Well, it had a little help. While water is traveling through soil, it becomes slightly acidic

“嗯，它还得到了点帮助。水在流过土壤时，会变得带有微弱的酸性。

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Limestone dissolves easily in acid — sort of like sugar in hot tea —

石灰岩在酸中很容易溶解——有点像糖在热茶里——

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so when water flows through cracks in limestone for thousands of years, it forms these enormous caverns

所以当水流过石灰岩的裂缝数千年时，就形成了这些巨大的洞穴。

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When the water table drops, these caves are left empty, or rather, full of air."

当地下水位下降时，这些洞穴就空了出来，或者说，充满了空气。”

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" So that's what makes the holes, but what makes these weird rocks?" Will asked

“所以这就是洞形成的原因，但这些奇怪的石头是怎么形成的？”威尔问道。

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" I'm getting to that. When the acidic water dissolves limestone, it absorbs the mineral from the stone

“我正要说到这个。当酸性水溶解石灰岩时，它会从石头中吸收矿物质。

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When the water drips from the ceiling of a cavern, it encounters air again and the opposite happens; the mineral dissolved in the water comes out

当水从洞穴顶部滴下时，它再次遇到空气，相反的过程发生了；溶解在水中的矿物质析出。

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Every time a water droplet falls, a little of that mineral stays on the ceiling

每当一滴水滴落时，一点点矿物质就会留在顶部。

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Over time the mineral builds up to form stalactites, these cones hanging from the ceiling

随着时间的推移，矿物质堆积形成钟乳石，就是从顶部垂下的锥状物。

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When the drop hits the floor, a little of the mineral is deposited there too, which builds stalagmites, the cones rising from the floor."

当水滴落到地面时，一点点矿物质也会沉积在那里，形成石笋，就是从地上长出的锥状物。”

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" Stalactites and stalagmites... I'll never remember which is which!" Will interrupted

“钟乳石和石笋……我永远记不住哪个是哪个！”威尔打断道。

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" Here's a trick to help you keep them straight: stalactites hold tight to the ceiling, and stalagmites might reach the ceiling," QT offered

“教你分清它们的小窍门：钟乳石紧贴着天花板，石笋或许能长到天花板。”QT提示道。

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" Anyway, they sometimes grow so long that they meet in the middle, forming a column."

“而且它们有时长得很长，会在中间连在一起，形成石柱。”

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" Cool," Will remarked. As he continued down the tunnel, he saw another huge formation." What's that?"

“酷。”威尔说。他沿着通道继续走，又看到一个巨大的形态。“那是什么？”

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" It's flowstone. It's really common in caves," QT explained

“那是流石，在洞穴里很常见。”QT解释说。

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" And those thin tubes hanging from the ceiling are called soda straws, for obvious reasons."

“还有那些吊在天花板上的细管，叫吸管状钟乳石，原因显而易见。”

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Will reached for one, and QT beeped in alarm." Don't touch the formations! They're very fragile!"

威尔伸手去摸，QT立刻嘟嘟报警：“别碰那些沉积形态！它们非常脆弱！”

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After Will pulled his hand back, QT continued." They can break, and the oil on our hands interferes with their growth."

威尔缩回手后，QT继续说：“它们容易断，而且我们手上的油脂会影响它们生长。”

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" Oh. Okay." Will didn't try to touch anything else as he walked along

“哦。好吧。”威尔继续走着，不再尝试碰其他东西。

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Finally QT said," Well, we've reached the deepest part of this cave system

最后QT说：“好了，我们已经到了这个洞穴系统最深的部分。

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It's also the youngest part. We're over one hundred meters below the surface

这也是最年轻的部分。我们在地表一百多米以下了。

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You know you've reached the bottom when you see lots of water. There are many underground rivers and lakes."

当你看到很多水的时候，你就知道到底部了。这里有许多地下河和地下湖。”

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" And there's something swimming in the water!" Will exclaimed

“而且水里还有东西在游！”威尔喊道。

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" Believe it or not, certain species spend their entire lives in caves

“信不信由你，有些物种一辈子都生活在洞穴里。

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Caves are unique because the conditions inside them stay the same all year

洞穴很独特，因为里面的条件全年保持不变。

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It's always dark, humid, and the temperature doesn't change much

这里永远是黑暗、潮湿的，而且温度变化不大。

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These species have adapted to help them survive here

这些物种已经进化适应，帮助它们在这里生存。

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Like many other cave creatures, that species of fish has lived in complete darkness so long that it's gone blind. But it's very sensitive to movement."

像许多其他洞穴生物一样，那种鱼在完全黑暗中生活得太久，已经失明了。但它对移动非常敏感。”

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" It's completely white too!"

“它也是全白的！”

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" Most cave species are very pale or white

“大多数洞穴物种都非常苍白或呈白色。

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Since no animal can see without light, there's no need to spend valuable energy developing color."

既然没有动物能在无光时看见，就没必要花费宝贵的能量去形成颜色。”

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Will walked up a steep tunnel branching away from the river

威尔走上了一条从河边岔出去的陡峭隧道。

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After a few minutes, he leaned against the wall to rest

几分钟后，他靠在洞壁上休息。

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" Ahhh!" Will screamed and jumped away." Something touched my hand!"

“啊！”威尔尖叫着跳开。“有东西碰了我的手！”

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He looked closely and saw a little bug

他仔细一看，看到了一只小虫子。

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" That's just a cave cricket," QT explained." It's harmless

“那只是一只洞穴蟋蟀，”QT解释道。“它无害。

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Its long limbs and antennae are another adaptation

它长长的附肢和触角是另一种适应性特征。

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They help the cricket find food and avoid predators, since it can't see."

它们帮助蟋蟀寻找食物和躲避捕食者，因为它看不见。”

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Will continued to climb, and soon a glimmer of light appeared ahead

威尔继续往上爬，很快前方出现了一丝微光。

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He reached the top of the tunnel and crawled inside a huge cave

他到达隧道顶端，爬进了一个巨大的洞穴。

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" Yikes!" Will froze when he spotted dozens of bats flying near the ceiling

“哎呀！”当看到几十只蝙蝠在洞顶附近飞舞时，威尔僵住了。

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" Don't be afraid, Will," QT said." Bats aren't dangerous

“别害怕，威尔，”QT说。“蝙蝠并不危险。

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They're quite useful; a single bat can eat three thousand bugs a night!

它们相当有用；一只蝙蝠一晚上能吃掉三千只虫子！

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Because they hunt in darkness — in caves and outside at night — they rely on sound instead of sight to find insects."

因为它们在黑暗中捕猎——在洞穴里和夜晚的户外——它们依靠声音而不是视觉来寻找昆虫。”

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A bat flew so close to Will's face that he felt the breeze from its wings

一只蝙蝠飞得离威尔的脸非常近，他甚至感觉到了它翅膀扇起的微风。

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He closed his eyes and took a deep breath before moving again

他闭上眼睛，深吸了一口气，然后才继续往前走。

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When he opened his eyes, he saw that he was back in his room. A breeze drifted in through the window

当他睁开眼睛时，他看到自己回到了房间里。一阵微风从窗户飘进来。

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" Whew. I'm glad I don't live in a cave," he said," but maybe I'll ask Mom if we can visit one."

“呼。真高兴我没住在洞穴里，”他说，“但也许我会问问妈妈我们能不能去参观一个。”