俄勒冈青蛙数量急剧减少的调查分析

21 俄勒冈青蛙数量急剧减少的调查分析

DATE=5-11-01
TITLE=ENVIRONMENT REPORT - Oregon Frog Study
BYLINE=Cynthia Kirk

（Start at 59" ）This is Bill White with the VOA Special English ENVIRONMENT REPORT.
Scientists have tried for years to understand what is causing (1) frogs to disappear around the world. Since Nineteen-Eighty, at least twenty kinds of frogs have (2) disappeared.  Many explanations have been proposed¹.  They include pollution, infections and (3) unidentified environmental threats.  
Scientists have warned about the possible harm to the environment caused by warming of the Earth. Now researchers say they have evidence that climate change could be a cause of the frog deaths. The findings² are the first to link climate change with the decreasing frog population in North America. 
A team of researchers studied frog eggs in small bodies of water in the northwestern American state of Oregon. Joseph Kiesecker led the study in Oregon's northern （4）Cascade Mountains. 
Scientists have known for years that frog eggs in the western states are dying³ from a fungal infection in water. The latest research suggests that the infection is the result of a complex series of events caused by warming temperatures.  
The scientists believe the frogs' eggs become infected because water levels where the eggs are laid are too low. They say climate change has reduced the amount of rainfall in areas where the frogs lay their eggs.  Lower water levels permit more dangerous （5）ultraviolet⁴ light from the sun to reach the eggs. Ultraviolet radiation can cause the eggs to lose their ability to resist deadly fungal infections. 
The researchers had done other experiments in the mountains. In those studies, scientists thought that ultraviolet radiation from the decreasing amount of ozone⁵ in the atmosphere was causing the frog deaths. Ozone in the upper atmosphere blocks ultraviolet radiation from the sun. 
Some scientists disagree with the new study. They say the effects of ultraviolet radiation in Oregon probably would not happen anywhere else. They also disagree about whether the (6) fungal infection is the direct cause of the frog deaths. Some scientists say the （7）fungus could have developed in the eggs after they had already died of a different cause. 
Scientists note that not all of the world's frogs lay their eggs in water. They say there are probably many reasons for the decreasing populations of frogs around the world.  
This VOA Special English ENVIRONMENT REPORT was written by Cynthia Kirk.

注释：
(1)  frog[ frC^ ]n.青蛙
(2) disappear[ 7disE5piE ]vi.消失, 不见
(3) unidentified[ 5Qnai5dentifaid ]adj.未经确认的
(4) cascade[ kAs5keid ]n.小瀑布, 喷流vi.成瀑布落下
(5) ultraviolet[ 5QltrE5vaiElit ]adj.紫外线的, 紫外的n.紫外线辐射
(6) fungal[ 5fQN^El ]adj.真菌的
(7) fungus[ 5fQN^Es ]n.菌类, 蘑菇

1 proposed   

被提议的

参考例句：

• There is widespread discontent among the staff at the proposed changes to pay and conditions. 员工对改变工资和工作环境的建议普遍不满。
• an outcry over the proposed change 对拟议的改革所发出的强烈抗议

2 findings   

n.发现物( finding的名词复数 )；调查（或研究）的结果；（陪审团的）裁决

参考例句：

• It behoves us to study these findings carefully. 我们理应认真研究这些发现。
• Their findings have been widely disseminated . 他们的研究成果已经广为传播。

3 dying   

adj.垂死的，临终的

参考例句：

• He was put in charge of the group by the dying leader.他被临终的领导人任命为集团负责人。
• She was shown into a small room,where there was a dying man.她被领进了一间小屋子，那里有一个垂死的人。

4 ultraviolet   

adj.紫外线的；n.紫外线

参考例句：

• It's called ultraviolet rays.它被叫做紫外线。
• The sun's ultraviolet rays are responsible for both tanning and burning.阳光中的紫外线是皮肤晒黑和灼伤的根源。

5 ozone   

n.臭氧，新鲜空气

参考例句：

• The ozone layer is a protective layer around the planet Earth.臭氧层是地球的保护层。
• The capacity of ozone can adjust according of requirement.臭氧的产量可根据需要或调节。