Older Volcanic Eruptions

　　Volcanoes were more destructive in ancient history, not because they were bigger, but because the carbon dioxide they released wiped out life with greater ease.

　　Paul Wignall from the University of Leeds was investigating the link between volcanic eruptions and mass extinctions. Not all volcanic eruptions killed off large numbers of animals, but all the mass extinctions over the past 300 million years coincided with huge formations of volcanic rock. To his surprise, the older the massive volcanic eruptions were, the more damage they seemed to do. He calculated the "killing efficiency" for these volcanoes by comparing the proportion of life they killed off with the volume of lava that they produced. He found that size for size, older eruptions were at least 10 times as effective at wiping out life as their more recent rivals.

　　The Permian extinction, for example, which happened 250 million years ago, is marked by floods of volcanic rock in Siberia that cover an area roughly the size of western Europe. Those volcanoes are thought to have pumped out about 10 gigatonnes of carbon as carbon dioxide. The global warming that followed wiped out 80 per cent of all marine genera at the time, and it took 5 million years for the planet to recover. Yet 60 million years ago, there was another huge amount of volcanic activity and global warming but no mass extinction. Some animals did disappear but things returned to normal within ten thousands of years. "The most recent ones hardly have an effect at all," Wignall says. He ignored the extinction which wiped out the dinosaurs 65 million years ago, because many scientists believe it was primarily caused by the impact of an asteroid. He thinks that older volcanoes had more killing power because more recent life forms were better adapted to dealing with increased levels of CO2.

　　Vincent Courtillot, director of the Paris Geophysical Institute in France, says that Wignall's idea is provocative. But he says it is incredibly hard to do these sorts of calculations. He points out that the killing power of volcanic eruptions depends on how long they lasted. And it is impossible to tell whether the huge blasts lasted for thousands or millions of years. He also adds that it is difficult to estimate how much lava prehistoric volcanoes produced, and that lava volume may not necessarily correspond to carbon dioxide emissions.

　　詞匯：

　　Bunch n. 群

　　Marathon n. 馬立松;耐力活動

　　fundraiser n. 募捐

　　weather v. 經(jīng)受風(fēng)雨

　　bureaucracy n. 官僚機(jī)構(gòu)

　　注釋：

　　1.Putting a bunch of college students in charge of a$300，000 Dance Marathon，fundraiser surely sounds a bit risky.讓一群大學(xué)生去負(fù)責(zé)募集30萬美元的馬拉松式的跳舞活動，這種募捐聽起來肯定有點兒冒險。“putting...in charge of...”是“讓……負(fù)責(zé)”。

　　2.Yvonne Fangmeyer, director of the student organization office at the University of Wisconsin, conducted a survey in February of students involved in campus organizations.Yvonne Fangmeyer是威斯康星大學(xué)學(xué)生組織辦公室主任，在二月組織了一次學(xué)生參加校園組織的調(diào)查。“a survey of students involved in campus organizations”太長了，所以“in February”插到了中間。

　　3.“teamup”是“參加”。

　　練習(xí)：

　　1. An extracurricular activity like raising a fund of $300,000 is risky because most student leaders

　　A) are lazy.

　　B) are stupid.

　　C) are not rich enough.

　　D) wilt not take an interest in it.

　　2. American students join campus organizations mostly for

　　A) making a difference.

　　B) gaining experience.

　　C) building friendship.

　　D) improving their resumes.

　　3. Who is Katie Rowley?

　　A) She's a senior professor.

　　B) She's a senior student.

　　C) She's a senior official.

　　D) She's a senior citizen

　　to carry an activity through to a successful end?

　　A) Passion.

　　B) Money.

　　C) Power.

　　D) Fame.

　　5. The phrasal verb fatten up in paragraph 6 could be best replaced by

　　A) invent.

　　B) rewrite.

　　C) polish.

　　D) complete.

　　答案與題解：

　　1.D 問題問的是：像募集30萬美元的的課外活動有點冒險是為什么?答案可以從第二段的第一句話中找到。第一句話是這么說的：大多數(shù)學(xué)生頭頭并不想在它們不感興趣的事上花大量的時間。

　　2.C 問題問的是：美國學(xué)生參加校園組織的主要目的是什么?答案可以從第三段找到。第三段是這么說的：威斯康星大學(xué)學(xué)生組織辦公室主任Yvonne Fangmeyer在二月組織了一次學(xué)生參加校園組織的調(diào)查。她說，尋求友誼是最經(jīng)常列舉的理由。

　　3.B問題問的是：Katie Rowley是誰?文章提到了好幾個人，Katie Rowley是其中的一個。第五段講到了Katie Rowley。“a Wisconsin senior”是“威斯康星四年級學(xué)生”。

　　4.A 問題問的是：為了把一項活動順利地貫徹到底學(xué)生頭頭需要什么?答案可以從倒數(shù)第二段找到。第一句話是這么說的：但是，如果沒有激情(passion)，學(xué)生頭頭試圖經(jīng)受急風(fēng)暴雨的考驗是會有困難的。

　　5.C 問題問的是：哪個詞替換第6段中的“fatten up”最合適?“fatten up”原義是“使

　　人或動物變肥”，在這里可以解釋為使一個人的履歷更充實一些，因此也好看一些。因此意思上最接近的是“polish”(潤色)。

　　譯文：

遠(yuǎn)古火山噴發(fā)

　　古代的火山更具殺傷力，不是因為它們更大，而是因為它們釋放出來的二氧化碳更容易把人殺死。

　　來自里茲大學(xué)的Paul Wignall正在調(diào)查火山爆發(fā)和大規(guī)模物種滅絕之間的聯(lián)系。不是所有的火山都會造成大量動物死亡。但在過去的三億年間，巨大的火山巖石的形成都伴隨著大規(guī)模種族滅絕。讓他驚奇的是，遠(yuǎn)古的火山造成的破壞更大。他通過比較火山釋放出的熔巖的體積與殺死生命的比例計算這些火山的殺傷效力。他發(fā)現(xiàn)，體積相同的情況下，老遠(yuǎn)古火山要比近期火山的殺傷力大十倍。

　　例如，發(fā)生在兩億五千年前的二疊紀(jì)物種滅絕就與西伯利亞的火山爆發(fā)發(fā)生在同一時期。當(dāng)時的火山巖大約覆蓋了西歐那么大的面積。當(dāng)時火山釋放出了大約100億噸梯恩梯的二氧化碳，隨之而來的全球變暖殺死了80％的海洋生物。500萬年以后，地球才恢復(fù)到原來的狀態(tài)。然而，6000年前，火山大規(guī)模爆發(fā)，以及而后的全球變暖并沒有帶來種族滅絕。一些動物確實消失了，但幾萬年以后，地球又恢復(fù)到以前的水平。“最近的一次火山爆發(fā)基本上沒帶來什么影響。”Wignall稱。他并沒有將650萬年前的恐龍滅絕計算在內(nèi)，因為大部分的科學(xué)家認(rèn)為那是有小行星撞擊地球所引起的。他認(rèn)為，遠(yuǎn)古火山之所以殺傷力大是因為近期的生物能夠更好的適應(yīng)二氧化碳含量上升。

　　法國巴黎地理研究所的所長Vincent Courtillot稱Wignall的觀點很具爭議性，并且很難做出這樣的計算。他指出火山爆發(fā)的殺傷力是由其持續(xù)長度所決定的。并且很難知道是否大規(guī)模爆發(fā)會持續(xù)上百萬年。他補充道，很難計算遠(yuǎn)古火山灰噴發(fā)多少火山巖，并且火山巖的數(shù)量也不一定和二氧化碳釋放數(shù)量相一致。

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