and only five, including Alvin, that can reach the depths of the "abyssal plain"—the deep ocean floor—that covers more than half the planet's surface. 只有5条，包括“阿尔文”号在内。能够抵达覆盖半个多地球表面的“深海平原”——深处的海床。

　　A typical submersible costs about $25,000 a day to operate, 一条普通的探海艇的运作费高达每天25000美元，

　　so they are hardly dropped into the water on a whim, still less put to sea in the hope that they will randomly stumble on something of interest. 因此几乎不会随便沉人海里，更不会到海里去瞎碰瞎撞，指望能碰上撞上什么有意思的东西。

　　It's rather as if our firsthand experience of the surface world were based on the work of five guys exploring on garden tractors after dark. 我们对于地球表面的第一手经验，就好像是建立在五个家伙夜间开着拖拉机进行的探索工作的基础上的。

　　According to Robert Kunzig, humans may have scrutinized "perhaps a millionth or a billionth of the sea's darkness. Maybe less. Maybe much less." 罗伯特·孔齐希说，人类也许只是察看了“大海暗处的百万分之一，或十亿分之一也许更少。也许少得多。”

　　But oceanographers are nothing if not industrious, and they have made several, important discoveries with their limited resources 但是，海洋学家们兢兢业业，以有限的资源取得了几项重要的发现，

　　including, in 1977, one of the most important and startling biological discoveries of the twentieth century. 包括20世纪一项最重大的生物学发现。

　　In that year Alvin found teeming colonies of large organisms living on and around deep-sea vents off the Galapagos Islands, 1977年，“阿尔文”号发现大群大群的大生物生活在加拉帕戈斯群岛附近的深海喷气孔上和周围，

　　tube worms over ten feet long, clams a foot wide, shrimps and mussels in profusion, wriggling spaghetti worms. 3米长的多毛虫，30厘米宽的蛤蜊，大量的虾和蚌，蠕动的管状虫。

　　They all owed their existence to vast colonies of bacteria that were deriving their energy and sustenance from hydrogen sulfides, 他们都认为，这些生物的存在要归因于大群大群的细菌；这些细菌又从硫化氢，

　　compounds profoundly toxic to surface creatures—that were pouring steadily from the vents. 对地面生物毒性极大的化合物——获取它们所需要的能量和营养，而硫化氢正源源不断地从喷气孔里冒出来。