Icy Microbes

　　1　In ice that has sealed a salty Antarctic lake for more than 2,800 years, scientists have found frozen bacteria and algae that returned to life after thawing. The research may help in the search for life on Mars, which is thought to have subsurface lakes of ice.

　　2　A research team led by Peter Doran of the University of Illinois at Chicago drilled through more than 39 feet of ice to collect samples of bacteria and algae. When Doran’s team brought them back and warmed them up a bit, they sprang back to life.

　　3　Doran said the microbes have been age-dated at 2,800 years old, but even older microbes may live deeper in the ice sheet sealing the lake, and in the briny water below the ice.1 That deeper ice and the water itself will be cautiously sampled in a later expedition that will test techniques that may one day be used on Mars.

　　4　Called Lake Vida, the 4.5-square-kilometer body is one of a series of lakes located in the McMurdo Dry Valleys of Antarctica, some 2 ,200 kilometers due south2 of New Zealand. This lake has been known since the 1950s, but people ignored it because they thought it was just a big block of ice. While at the site for other research in the 1990s, Doran and his colleagues sent3 radar signals into the clear ice covering the lake and were surprised to find that 62 feet below there was a pool of liquid water that was about seven times more salty than seawater.

　　5　That prompted the researchers to return in 1996 with equipment to drill a hole down to within a few feet of the water layer. At the bottom of this hole, researchers harvested specimens of algae and bacteria.

　　6　The researchers will return in 2004 equipped with instruments that are sterilized. They will then drill through the full 62 feet of ice and sample some of the briny water from the lake for analysis. The water specimen will be cultured to see if it contains life. Specimens from the water are expected to be even older than the life forms extracted from the ice covering.

　　注释：

　　1.... live deeper in the ice sheet sealing the lake, and in the briny water below the ice：in the ice sheet sealing the lake和in the briny water below the ice是介词短语，用作状语，修饰live。

　　2.due south：正南

　　3.While at the site for other research in the 1990s, Doran and his colleagues sent ... ：While at the site for other research in the 1990s是省略句，写全了就是：While Doran and his colleagues were at the site for other research in the 1990s ...

　　练习：

　　1.Paragraph 2 ________

　　2.Paragraph 3 ________

　　3.Paragraph 4________

　　4.Paragraph 6________

　　A　Significance of Testing Techniques for Sampling Microbes in the Deep Ice Sheet

　　B　Special Features of Lake Vida

　　C　Later Expedition on Mars

　　D　2004 Revisit Planned for Collecting Lake Water Specimens

　　E　Antarctic Frozen Life Sampled and Revived

　　F　Accidental Disovery of Ice-sealed Lake Water in Antarctica

　　5.Scientists ignored Lake Vida because they thought that a lake of ice ________.

　　6.Scientists expect that the life, if found in deeper water below the ice sheet, ________.

　　7.What the scientists will do in 20Q4 ________.

　　8.The salt concentration in the liquid water of Lake Vida ________

　　A　is found to be a great deal higher than that of seawater

　　B　was of little scientific value

　　C　may be older than that collected below 39 feet of ice

　　D　might have come from Mars

　　E　is to collect some briny lake water for analysisy

　　F　may return to life sooner than microbes frozen in the surface ice

答案与题解：

　　1.E　本段谈及Doran考察队在南极冰块上钻洞深达39英尺，获得微生物和水藻的样本。解冻后这些微生物和水藻又复活了。选项E概括了本段的大意。

　　2.A　本段的大意是试验冰层深处提取生命样本的技术可能有一天会用于火星生命的探索。

　　3.F　本段要表达的意思是：冰下湖是科学家在做other research时偶然发现的。

　　4.D　本段说的是科学家2004年还要对布下湖再次进行考察。

　　5.B　选B的依据是第四段第二句。little scientific value是根据科学家当时认定Lake Vida只是a big block of ice而推论出来的。

　　6.C　选C的依据见第三段第一句。

　　7.E　选E的依据见第六段第二句。

　　8.A　第四段最后一句是选A的依据。

　　译文：冰冻微生物

　　在一个南极咸水湖封冻了 2800多年的冰块中，科学家发现，冰冻的微生物和水藻在解冻后又复活了。该研究成果可能会有助于寻找火星上的生命，人们认为火星的地表下面有冰湖。

　　由芝加哥的伊利诺伊大学的 Peter Doran率领的考察队在南极冰块上钻洞深达39英尺，采集了微生物和水藻的样本。 Doran的考察队将其带回并给其温暖环境，这些样本竟又复活了。

　　Doran说，这些微生物有 2800年的高龄，但是或许还有更老的微生物生存在封湖冰块的更深层和冰块下面的咸水中。在以后的深险中，还会谨慎地对更深的冰层和水提取样本，对将来或许会用于火星的技术进行检测。

　　这个湖名叫 Vida湖，面积为 4.5平方公里，是南极洲上位于 McMurd干谷的湖群中的一个，位于新西兰正南约2200千米处。该湖在 20世纪 50年代已为人知，但过去人们认为这只不过是一个巨大的冰块，所以不曾引起足够的重视。但是在 20世纪 90年代，在进行其他考察的地方， Doran和同事们往覆盖湖面的清澈的冰层中发出雷达信号，惊奇地发现在62英尺深处居然有一个水潭，这里的水其咸度大约是海水的 7倍。

　　于是，1996年，考察人员带着设备再次来到南极。钻出一个深及水层数英尺的洞。在洞底，考察人员采集到了水藻和微生物的样本。

　　2004年，考察人员将携带经过杀菌的仪器再次回到南极。他们将在 62英尺的冰层上钻洞，对从湖中提取咸水的样本进行分析。水的样本将会受到培育，看其是否含有生命。据预测，水中提取样本的历史甚至会比冰层中提取的生命形式的历史还要长。