雅思课外读物--New theory for the Mass Extinction（大规模灭绝）

摘要：今天要跟大家分享的雅思阅读素材题目是“New Theory for What Caused Earth's Second-Largest Mass Extinction”地球第二次大灭绝的新理论？会不会是有毒的金属在海洋中产生的畸变呢？本文给你答案！

Today, expanding dead zones, such as a giant one at the mouth of the Mississippi River, are triggered by nitrogen-rich fertilizer and other runoff from cities and farms.

In addition, scientists say warming temperatures are sucking oxygen out of deep ocean waters, making enormous stretches of the seas hostile(不友好的)to marine life.

Although heavy metal loads could increase in these zones, it’s unlikely to occur on the scale seen during the major historical extinctions.

Still, “thec hemical processes that we describe are similar between the ancient and the modern ocean,” Emsbo says. “So our study might indeed help highlight processesa nd hidden consequences caused by fluxes of anthropogenic(人类产生的)elements to the world’s oceans.”

Vocabulary

Toxic 有毒的

Depleted 耗尽的

Deformity 畸形

Plankton 浮游生物

Teem 充满

Scenario 场景;剧情

Implicate 暗示

Influx 涌入

Pronounced 明显的

Salinity 盐分

Hypothesis 假说

Intriguing 有趣的

Disrupt 破坏

Vertebrate 脊椎的

Hostile 敌对的;不友好的

Anthropogenic 人类产生的

本文长句翻译

1.The fossils displayed as many as 100 times more deformations than expected from background studies, along with up to 10 times greater heavy metal concentrations.

这些化石显示出来的畸形比相关背景研究预料的要多100倍，同时，其重金属浓度也要高10倍。

2.While changes in sunlight, pH or salinity(盐分)levels can also trigger deformities in marine life, scientists have found little evidence that any of these occurred at the onset of the Ordovician-Silurian extinction.

虽然日照、PH值及盐分度变化也可能引发海洋生物产生畸形，但科学家们找不到证据来证明在奥陶纪和志留纪之初以上任何变化曾经发生过。

3.While the scientists can't say exactly what caused the depleted oxygen in the ocean millions of years ago, leading theories center on increases in nutrients, such as nitrogen, that cause plants to grow faster and use up all the oxygen.

虽然科学家们不能确切解释千百万年前海洋中氧气枯竭到底缘何发生，但普遍接受的理论都认为，营养物质(比如氮素)的增加导致植物生长加快，从而用完了所有的氧气。

注：以上2、3句都是while引导的让步从句，这里的while相当于although。此类句子在英语文章中使用非常广泛，请务必掌握。