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托福阅读材料之深海生物生存方式

2015-01-16 17:52:36来源：网络

　　2015年托福考试已经开始，对于每一位参加托福考试的同学来说必须抓紧时间提高效率，那么我们对于托福听说读写都需要采取怎样的复习方法?这四项又需要注意些什么呢?我们分别谈一下。托福阅读备考我们需要掌握大量的词汇以及长难句的理解和一些背景材料，如果勤练习真题加上方法技巧，相信大家会有不错的收获。下面是新东方在线托福小编整理的托福阅读材料之深海生物生存方式，供同学们参考!

　　阳光是让生命获得能量的重要来源，因此之前大家都认为海洋深处生物无法存活。而随着水下探险技术的不断改进，人们对深海有了更多的认识。

　　Once it seemed that the ocean floor was a desert of darkness. As everyone knew, sunlight was what made life possible by fueling photosynthesis, and sunlight can penetrate only the first few hundred yards of the ocean’s great depths. Lower, a few creatures might still eke out a living by scrounging the organic detritus that drifts down from the surface of the sea. But thousands of feet down, in the utter blackness at the ocean’s bottom, there could be practically nothing.

　　Then, in 1977, underwater explorers discovered that there was in fact something, and quite a lot of it. At mid-ocean ridges, where new ocean floor rises up as molten rock from Earth’s interior, where cold seawater mixes with the rising magma and, heated to 650 degrees, spews back up through chimney-shaped hydrothermal vents, researchers stumbled across bustling ecosystems. Clinging to the sides of the chimneys were thick white mats of bacteria; around them were eight-foot-long stalk-shaped worms, rocking in the water, while eyeless shrimp seethed around the chimneys like maggots. All were thriving on the energy bound up in the vents’ sulfur compounds. The seafloor might still be dark, but now it was known to be dotted with gardens.

　　In just the past eight years, however, underwater explorers have discovered that this picture is still incomplete: there is light at the bottom of the sea. Hydrothermal vents glow, and while the light is too faint to be perceived by the human eye, that hardly means it is without significance. Physicists maintain that although some of the light may be created by the intense heat, much of it must be attributed to some as-yet- unknown process. Biologists, meanwhile, say there is sufficient light at these vents for photosynthesis to take place. Researchers can’t say yet whether any creatures are actually living off this light, but if they are, they will represent the first known instance of natural photosynthesis without sunlight. The evolutionary implications may run deeper: it’s possible not only that this deep light is fueling photosynthesis now, but that, 3.8 billion years ago, it got the whole process started.

　　本篇关键词：

　　Photosynthesis

　　thousands of feet down

　　ocean’s bottom

　　mid-ocean ridges

　　650 degrees

　　bustling ecosystems

　　bound up in

　　sulfur compounds

　　light at the bottom of the sea

　　photosynthesis without sunlight

　　中文相关知识：

　　无处不在的细菌：没有阳光就不能进行光合作用，地面生物就无法生存了。但是在2000—3000米深的海底，没有阳光的地方，各种生物又是以什么为食物来维持生命呢?科学家从海底采取的水样中发现了奥妙。原来在水下2500到3000米的海底常有温泉出现，这些温泉喷涌出高达350摄氏度的水流。海底热泉水从地下带上来许多硫酸盐，硫酸盐在高温高压下变成了有臭鸡蛋味的硫化氢，一些以硫化氢为营养的细菌以极快的速度繁衍。细菌通过摄取温泉里丰富的化合物获得能量，它们帮助温泉水把周围变成一片生机勃勃的海底绿洲。小动物就以细菌为食，大动物又以小动物为食，这样就形成了新的食物链

　　以上就是新东方在线托福小编整理的托福阅读的相关内容，更多资讯敬请访问新东方在线托福频道，祝大家取得理想的成绩!


本文关键字: 托福阅读材料 深海生物

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