英语听力：自然百科 海洋天堂大堡礁:堡礁内外—23

This bleaching² occurs because corals can only live in a narrow temperature range, healthy corals get their color from microscopic³ algae⁴ living in their tissues, these manufacture food for the corals by photosynthesis⁵, but when the temperature rises just 2 degrees above the normal summer maximum, the algal cells are expelled because they no longer benefit the coral. The bleaching effect is the white chalky skeleton showing through the coral's transparent⁶ tissues, but they are not dead, not yet, they can survive in this bleach¹ state for several weeks, if the temperature drops, the corals aquire new algae from plankton⁷ floating by, but if the warm water persists, the coral dies. Coral bleaching hadn't been seen on the great barrier reef before the 1980s, due to global warming, bleaching is now more common, and cyclones⁸ are likely to be more frequent too, and there is something even more insidious⁹, temperature is rising because more and more carbon dioxide from human activity enters the atmosphere, this dissolves in sea water turning acidic which can stop coral growth, if they can't build their chalky skeletons, reefs will start to crumble¹⁰.

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1 bleach   

vt.使漂白；vi.变白；n.漂白剂

参考例句：

• These products don't bleach the hair.这些产品不会使头发变白。
• Did you bleach this tablecloth?你把这块桌布漂白了吗？

2 bleaching   

漂白法，漂白

参考例句：

• Moderately weathered rock showed more intense bleaching and fissuring in the feldspars. 中等风化岩石则是指长石有更为强烈的变白现象和裂纹现象。
• Bleaching effects are very strong and show on air photos. 退色效应非常强烈，并且反映在航空象片上。

3 microscopic   

adj.微小的，细微的，极小的，显微的

参考例句：

• It's impossible to read his microscopic handwriting.不可能看清他那极小的书写字迹。
• A plant's lungs are the microscopic pores in its leaves.植物的肺就是其叶片上微细的气孔。

4 algae   

n.水藻，海藻

参考例句：

• Most algae live in water.多数藻类生长在水中。
• Algae grow and spread quickly in the lake.湖中水藻滋蔓。

5 photosynthesis   

n.光合作用

参考例句：

• In apple trees photosynthesis occurs almost exclusively in the leaves.苹果树的光合作用几乎只发生在叶内。
• Chloroplasts are the structures in which photosynthesis happens.叶绿体就是光合作用发生的地方。

6 transparent   

adj.明显的，无疑的；透明的

参考例句：

• The water is so transparent that we can see the fishes swimming.水清澈透明，可以看到鱼儿游来游去。
• The window glass is transparent.窗玻璃是透明的。

7 plankton   

n.浮游生物

参考例句：

• Plankton is at the bottom of the marine food chain.浮游生物处于海洋食物链的最底层。
• The plankton in the sea feeds many kinds of animals. 海的浮游生物成为很多种动物的食物。

8 cyclones   

n.气旋( cyclone的名词复数 )；旋风；飓风；暴风

参考例句：

• The pricipal objective in designing cyclones is to create a vortex. 设计旋风除尘器的主要目的在于造成涡旋运动。 来自辞典例句
• Middle-latitude cyclones originate at the popar front. 中纬度地区的气旋发源于极锋。 来自辞典例句

9 insidious   

adj.阴险的，隐匿的，暗中为害的，（疾病）不知不觉之间加剧

参考例句：

• That insidious man bad-mouthed me to almost everyone else.那个阴险的家伙几乎见人便说我的坏话。
• Organized crime has an insidious influence on all who come into contact with it.所有和集团犯罪有关的人都会不知不觉地受坏影响。

10 crumble   

vi.碎裂，崩溃；vt.弄碎，摧毁

参考例句：

• Opposition more or less crumbled away.反对势力差不多都瓦解了。
• Even if the seas go dry and rocks crumble,my will will remain firm.纵然海枯石烂，意志永不动摇。