VOA慢速英语2015 科幻变成现实的物种调查

 

AS IT IS 2015-01-09 Science Fiction Becomes Reality for Species Surveys 科幻变成现实的物种调查

Many science fiction stories tell about explorers arriving in a new world. The explorers then use some kind of high-tech¹ device to test for breathable air or signs of life. But here on Earth, science fiction is becoming reality through a new sampling technology called environmental DNA², or eDNA for short. Scientists can use it to identify rare or invasive species, study biodiversity or estimate fish populations with just a little air or water.

Ryan Kelly is an ecologist at the School of Marine³ and Environmental Affairs at the University of Washington in Seattle. He works in a laboratory there with other researchers. They study the genetic⁵ material released by living creatures.

"Essentially⁶ we can take a sample of soil or air -- and in our case -- water, and we can sequence the DNA out of it and tell you what is there."

Ryan Kelly says he and his research team are studying water samples collected from Puget Sound. He says the cost of gene⁴ sequencing has "plummeted⁷ in recent years." That makes DNA testing more widely available.

Environmental DNA can be used in two ways. One is to identify the creatures that live in a certain place. The other is to confirm the presence or lack of a specific creature.

Caren Goldberg heads the new eDNA lab at Washington State University in Pullman, Washington. She is one of the first biologists in the northwestern United States to take the technology from the testing phase to actually using it.

"It is extremely useful for species that are really hard to find. I have spent many hours looking for species that I was pretty sure were there -- looking under rocks, looking in water, doing all kinds of surveys."

Caren Goldberg sees eDNA as a way to get answers more efficiently⁸, safely and with less destruction compared to traditional survey techniques. Until recently, scientists depended on snorkeling, netting or using an electric current to temporarily capture fish.

"We're absolutely at this point where proof-of-concept has been established. I don't think everyone necessarily is on board yet, but I think the majority of the people are on board."

This newer way to identify what lives in the environment is becoming popular around the world. Animal experts in Vietnam are using the eDNA to find the last, wild Yangtze giant softshell turtles. One researcher on the Caribbean island of Trinidad is using the sampling technology to find endangered golden treefrogs. And in Madagascar, it is being used to identify amphibian⁹ diseases.

Ms. Goldberg has used eDNA testing to confirm the local extinction¹⁰, disappearance¹¹, of a leopard¹² frog in the American state of Idaho. She has also been asked to document the spread of the New Zealand mudsnail in the state of Washington. The creature has been found in lakes and other waterways across the state.

Now, the U.S. Bureau of Land Management wants Caren Goldberg to look for the Columbia spotted¹³ frog in two other western states. The rare amphibian is a candidate for the federal government’s threatened species list.  

Scientists working with the technology say they do not expect robots to replace field biologists anytime soon. But the old-fashioned field work could soon be more targeted.

A related research goal is to show how long environmental DNA can last and how far it can travel in different environments. 

Words in this Story

DNA – n. short for deoxyribonucleic acid; a substance that carries genetic information in the cells of plants and animals

ecologist – n. someone who studies the relationships between groups of living things and their environments

endangered – adj. threatened; used to describe an animal or plant that has become very rare and that could die out completely

extinction – n. the situation that results when something such as a plant or animal species dies out completely

phase – n.  a part or step in a process; part of a series of related events or actions

1 high-tech   

adj.高科技的

参考例句：

• The economy is in the upswing which makes high-tech services in more demand too.经济在蓬勃发展，这就使对高科技服务的需求量也在加大。
• The quest of a cure for disease with high-tech has never ceased. 人们希望运用高科技治疗疾病的追求从未停止过。

2 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

3 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

4 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

5 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

6 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

7 plummeted   

v.垂直落下，骤然跌落( plummet的过去式和过去分词 )

参考例句：

• Share prices plummeted to an all-time low. 股票价格暴跌到历史最低点。
• A plane plummeted to earth. 一架飞机一头栽向地面。 来自《简明英汉词典》

8 efficiently   

adv.高效率地，有能力地

参考例句：

• The worker oils the machine to operate it more efficiently.工人给机器上油以使机器运转更有效。
• Local authorities have to learn to allocate resources efficiently.地方政府必须学会有效地分配资源。

9 amphibian   

n.两栖动物；水陆两用飞机和车辆

参考例句：

• The frog is an amphibian,which means it can live on land and in water.青蛙属于两栖动物，也就是说它既能生活在陆地上也能生活在水里。
• Amphibian is an important specie in ecosystem and has profound meaning in the ecotoxicology evaluation.两栖类是生态系统中的重要物种，并且对环境毒理评价有着深远意义。

10 extinction   

n.熄灭，消亡，消灭，灭绝，绝种

参考例句：

• The plant is now in danger of extinction.这种植物现在有绝种的危险。
• The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。

11 disappearance   

n.消失，消散，失踪

参考例句：

• He was hard put to it to explain her disappearance.他难以说明她为什么不见了。
• Her disappearance gave rise to the wildest rumours.她失踪一事引起了各种流言蜚语。

12 leopard   

n.豹

参考例句：

• I saw a man in a leopard skin yesterday.我昨天看见一个穿着豹皮的男人。
• The leopard's skin is marked with black spots.豹皮上有黑色斑点。

13 spotted   

adj.有斑点的，斑纹的，弄污了的

参考例句：

• The milkman selected the spotted cows,from among a herd of two hundred.牛奶商从一群200头牛中选出有斑点的牛。
• Sam's shop stocks short spotted socks.山姆的商店屯积了有斑点的短袜。