VOA慢速英语2015 南极冰层下发现许多形式的生命

Many Life Forms Discovered Deep under Antarctic Ice 南极冰层下发现许多形式的生命

Scientists from the United States say they have found fish and other aquatic¹ creatures living under icy waters in Antarctica. They made the announcement after completing three months of research at the Ross Ice Shelf, the world’s largest floating ice sheet.

The researchers hoped to find clues to explain the force of the melting ice and its effect on sea level rise.

Antarctica is the driest, coldest and windiest place on Earth. Reed Scherer and Ross Powell are with Northern Illinois University in DeKalb, Illinois. They just finished up their research on our southernmost continent. Money for the project came from America’s National Science Foundation.

Professors Scherer and Powell describe their scientific investigation².

“The central focus of the research was to try to get some actual physical constraints⁴ on what the ice sheet looks like over time and what it is doing right now.”

“And so we chose a study site where, in the first year, we went into the subglacial lake and tried to understand the environment in there, both ecologically and in terms of the ice dynamics⁵ about how the lake operates, and how the sediment⁶ underneath⁷ the ice sheet operates, as well, because it's the water and the sediment underneath the ice that controls how fast the ice is flowing into the ocean.”

Ross Powell led the investigation. The team included scientists, engineers, mechanics and technicians. They used tractors to pull electric generators⁸, science laboratories, heavy machinery⁹ and other supplies across the ice. 

The tractors moved everything from the main U.S. scientific base at McMurdo Station to the researcher’s camp – a distance of 1,000 kilometers.

The camp was near a subglacial lake, where an earlier study took place. The researchers worked in an area called the grounding zone, where Antarctic ice, land and sea converge¹⁰.

Ross Powell says the latest study may provide evidence that can help predict the effect of climate change on rising sea levels.

“What we have found is that these are very sensitive areas to the stability of how dynamic the ice is and how fast the ice may react to increases of melting both from the ocean and the atmosphere.”

Among the new instruments built for the project was a powerful hot water drill. The researchers used the drill to dig down some 740 meters. They collected water, sediment and other material from the grounding zone.

Working around the clock before the deep hole refroze, they sent a video camera down to the 400-square-meter undersea area. 

Reed Scherer says the video images they saw in the Command Center were a total surprise. 

“It's a very mobile environment. The bottom is changing constantly. And so the things that we saw were all very mobile organisms, things that swim and some things that crawl. And obviously they are getting enough nutrition that they can thrive. Some of the little crustacean-like creatures called amphipods that we saw swam quite quickly and were quite active.”   

This is the farthest south that fish have ever been seen. How did the creatures get here? What do they feed on?  And what effect will the retreating ice have on them?

Ross Powell says the ice and sediment cores taken from the grounding zone can offer clues.

“We know that the ice is melting there at the moment and so by opening up the cores once they get back, we hope to be able to understand what the ice was doing in the past, relative to what it is doing now. And because it is melting so fast or seems to be melting fast at the moment, we anticipate that there will be some differences that we’ll see in the history of the ice sheet from the sediment cores, once we open them up.”

Ross Powell says the work raises more questions than it answers. Together with other researchers, he is planning to ask for financial help to continue studies of the frozen continent.

Words in this Story

constraint³ – n. something that limits or restricts someone or something

subglacial - adj. under a glacier¹¹ (a large area of thick ice and snow)

tractor – n. heavy machinery often used on a farm

converge – v. to come together; move toward one point and join together

around the clock – adj. happening or continuing all day and all night

organism –n. an individual living thing

1 aquatic   

adj.水生的，水栖的

参考例句：

• Aquatic sports include swimming and rowing.水上运动包括游泳和划船。
• We visited an aquatic city in Italy.我们在意大利访问过一个水上城市。

2 investigation   

n.调查，调查研究

参考例句：

• In an investigation,a new fact became known, which told against him.在调查中新发现了一件对他不利的事实。
• He drew the conclusion by building on his own investigation.他根据自己的调查研究作出结论。

3 constraint   

n.(on)约束，限制；限制(或约束)性的事物

参考例句：

• The boy felt constraint in her presence.那男孩在她面前感到局促不安。
• The lack of capital is major constraint on activities in the informal sector.资本短缺也是影响非正规部门生产经营的一个重要制约因素。

4 constraints   

强制( constraint的名词复数 )； 限制； 约束

参考例句：

• Data and constraints can easily be changed to test theories. 信息库中的数据和限制条件可以轻易地改变以检验假设。 来自英汉非文学 - 科学史
• What are the constraints that each of these imply for any design? 这每种产品的要求和约束对于设计意味着什么？ 来自About Face 3交互设计精髓

5 dynamics   

n.力学，动力学，动力，原动力；动态

参考例句：

• In order to succeed,you must master complicated knowledge of dynamics.要取得胜利，你必须掌握很复杂的动力学知识。
• Dynamics is a discipline that cannot be mastered without extensive practice.动力学是一门不做大量习题就不能掌握的学科。

6 sediment   

n.沉淀，沉渣，沉积(物)

参考例句：

• The sediment settled and the water was clear.杂质沉淀后，水变清了。
• Sediment begins to choke the channel's opening.沉积物开始淤塞河道口。

7 underneath   

adj.在...下面，在...底下；adv.在下面

参考例句：

• Working underneath the car is always a messy job.在汽车底下工作是件脏活。
• She wore a coat with a dress underneath.她穿着一件大衣，里面套着一条连衣裙。

8 generators   

n.发电机，发生器( generator的名词复数 )；电力公司

参考例句：

• The factory's emergency generators were used during the power cut. 工厂应急发电机在停电期间用上了。
• Power can be fed from wind generators into the electricity grid system. 电力可以从风力发电机流入输电网。 来自《简明英汉词典》

9 machinery   

n.(总称)机械，机器；机构

参考例句：

• Has the machinery been put up ready for the broadcast?广播器材安装完毕了吗？
• Machinery ought to be well maintained all the time.机器应该随时注意维护。

10 converge   

vi.会合；聚集，集中；(思想、观点等)趋近

参考例句：

• The results converge towards this truth.其结果趋近于这个真理。
• Parallel lines converge at infinity.平行线永不相交。

11 glacier   

n.冰川，冰河

参考例句：

• The glacier calved a large iceberg.冰河崩解而形成一个大冰山。
• The upper surface of glacier is riven by crevasses.冰川的上表面已裂成冰隙。