Water feels good when we're thirsty, cools us when we're hot, looks great in a pond, a lake, a cloud. Because we ourselves are two-thirds water, we like the stuff, we're drawn to it. We search the universe looking for signs of water and when we look back at our planet, we are small and pale, yes, but we're dazzlingly blue. 当我们口渴的时候，水就如甘露一样。当我们炎热的时候，水又能够让我们凉爽。池塘、湖泊、云朵中的水看起来都很棒。那是因为我们自身的2/3都是水，我们喜欢水，我们迷恋它。我们探索宇宙来寻找水的迹象，但当我们回望地球的时候，发现她又小又暗，但是确闪耀着蓝色。
It's good to be wet. Compared to our neighbors — Mars, Venus, the dust-dry Moon — we look the wettest. More than two thirds of our surface is ocean. Another twentieth is ice. Water, water, everywhere. We've got so much of it. 地球上有水真的很棒。与我们的邻居相比——火星、金星、干燥多尘的月球——我们是最多水的。地球表面2/3都是海洋。另外1/20是冰。到处都是水。我们拥有很多的水。 Or do we? 但这是真的吗？ There's an oceanographer in Hawaii, Mike Mottl by name, who's been measuring — or trying to measure — how much water we have on this planet, and his calculations are a little startling. When you stand on the shore of Lake Michigan, or the Pacific, the water supply looks impressive. But Mike changes perspective; he steps off the planet and considers the whole sphere, the surface, the crust, the mantle, the core and he asks, how much total water is there? Is Earth carrying a lot? Or a little? 在夏威夷有个叫做麦克莫特儿的海洋学家一直致力于测量或者尝试测量地球上有多少水。他的结果有些令人震惊。当你站在密歇根湖旁，抑或是太平洋边，水扑面而来，让人印象深刻。但是麦克改变视角；他着眼于地球之上，将地球看做一个整体，地表，地壳，地幔，地核，提出自己的疑问：地球上有多少水？地球上的水是很多还是很少？ So he starts counting. First, of course, are our oceans. On a map there are five big ones, but combines them into one "global ocean." 于是他开始计算。首先计算的肯定是海洋中的水资源。在下图中有五大块海洋，但是在计算中将它们总汇入一个“世界洋”。
Then come all the rivers, all the lakes, big and small ... 然后计算所有的河流，湖泊，无论大小。。。
Then the water in our atmosphere, the clouds, the fog, the moisture that hangs invisibly in the air... 然后计算大气中的水分，云朵中，雾中，空气中不可见的湿气中。。。
Then, hidden below us, are the underground pools of water, aquifers, that show themselves in wadis or oases in the desert, that you touch when you dig a well deep into the ground... 然后，藏于我们之下的地下水，包括地下湖中的，地下蓄水层的，沙漠中干涸河道或者绿洲中的。只要你在地上挖一个深井，你就可以接触到它们。
When Mike Mottl counts, he counts in Global Ocean units, all the oceans together. So when he adds up all the air, oceanic/lake/river and underground water he gets, roughly 1.2 "Global Oceans;" basically surface Earth is mostly ocean with a scoop of fresh water on top. 麦克莫特儿在计算时，把所有的大洋汇总到一起作为世界洋。然而，当他将所有空气中水，地表水以及地表水加起来时，大体上等于1.2个“世界洋”；基本上可以这么说，地球表面上空是一个拥有巨量水源的大洋。 But we're not done... 但是我们依然没有结束。。。 What about water inside the earth? 地球内部的水呢？ There are three layers: the upper mantle, lower mantle and the core. 地球内部分为三层：上地幔，下地幔以及地核。
In the upper mantle, or crust, there is water hiding in the tiny pores of certain "hydrous" minerals — in clay, in mica — and when conditions are right, that water can be squeezed out. When volcanoes erupt and you see a white billowing cloud hurtling to the sky, much of that is water vapor. Volcanoes belch water. How much is down there? Estimates vary (a lot) but Mottl figures there's maybe a fifth of a global ocean in the upper mantle. 在上地幔或者地壳中，有一些藏身于含水矿物质——黏土和云母——的微孔中的水。一旦条件合适，水就可以释放出来。当您看到火山喷发时喷涌而出的白色浪云时，云朵中大部分是水蒸气。火山喷射出水蒸气。那么下面有多少呢？估计应该有很多。但是莫特儿估计上地幔中的水应该有1/5世界洋那么多。 In the lower, bigger mantle, the calculations get more theoretical, and therefore chancy, but he guesses anywhere from one tenth to 1.8 global oceans. 在更大的下地幔中，计算将更为理论化，因此可能不太准确。麦克估计将会有0.1~1.8世界洋。 Then, all the way down, in the earth's core, nobody knows. There's enough capacity to house 60 oceans. Or maybe 100. The core could be very, very rich in hydrogen (a water ingredient) or totally dry. We have no data. Which leaves us in the odd position of not knowing where most of the Earth's water is. As Professor Mottl wrote me, 那么，继续往下，没有人知道地核之中的水有多少。地核可以储存60个，或者100个大洋的水。地核中可能有巨量的氢（水分子的一种组分）或者完全干燥。我们没有任何数据。这将让我们处于一种奇怪的处境：不知道地球上哪里水最多，正如莫特儿教授信中所说的那样。
哪里水最多呢？海洋？地壳和地幔？还是在地核中呢？我们不知道这个问题的答案。三者都有可能是最大的水源储藏地。 因此我问道；“如果你现在有个粗略的计算，没有人让您为其负责。 那么你认为地球上有多少水呢？”然后他说（尽管有点盲人摸象的感觉），地球上应该有三个世界洋那么多的水，1/3在上部，我们可以在里面游泳，航行，畅饮它同时也会被它淋到。另外的2/3都静静地藏身于地下矿物质里。 Three global oceans of water! Sounds like a lot, no? 3个世界洋那么多的水！听起来很多，还不够多吗？ But from Mike's point of view, when you consider the mass of the earth, three oceans would take up less than one tenth of one percent of the planet. Think of your car. One tenth of one percent of your car would be smaller than a paper cup. (Well, it depends on the car, but you get the idea.) 0.1% is a tiny fraction. 但是从麦克的观点来看，当你考虑到地球的质量的时候，3个世界洋的水也不足地球的1/1000.那你的车打个比方吧，车重量的1/1000还不如一个纸杯重呢。（虽然车的重量有大有小，但是你应该明白了）。1/1000真的很少。
Not only could we carry a lot more, there are other heavenly bodies, Europa, one of Jupiter's moons, for example, that are almost ENTIRELY water. So compared to what's out there, or what could be out there, while the Earth looks so very, very wet, all that blue sloshing around on the surface, actually — when you look closely...we're pretty dry. 不仅地球可以承载更多水资源，其它天体也可以。举个例子，木卫二，木星的一个卫星，几乎全部是水。所以与那里的水资源相比，或者推测的相比，虽然地球上水很多，表面全部都是蓝色的大洋，但是当我们仔细观察时。。。我们的水依然不多。 -------------------------------------------------------------------------------- ---------------------------------------------------------------------------------- Mike Mottl's paper (with Glazer, Kaiser and Meech) on Earth Water appeared in Water and Astrobiology. He and I have written back and forth, but I'm especially indebted to Mike's colleague Karen Meech, who walked me through this subject slowly and carefully. Any errors here, as usual, are all mine. 麦克米特尔（与Glazer,Kaiser和Meech)关于地球水源的文章将会在水和天体生物学上刊出。他和我来回探讨了多次。我同样要特别感谢麦克的同事Karen Meech，他循序渐进的帮助我了解了这个学科。正如往常一样，文章出现的的问题，都是我的错误。 |
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Benjamin Arthur 
