VOA慢速英语--融化的冰川露出营养丰富的土壤

Melting Glaciers¹ Uncover Nutrient-Rich Soil

Greenland's glaciers continue to melt away because of rising global temperatures. But the melting ice might provide a way to lessen² the impact of climate change.

As the ice melts, it deposits tiny silt³. Silt is very small sand, mud or other material carried by running water.

"It's a kind of wonder material," said Minik Rosing. He is a native Greenlander and professor at the University of Copenhagen.

Called glacial rock flour, the silt is crushed to tiny particles by the weight of the melting ice. One billion tons of the silt is deposited it per year on Greenland, the world's largest island.

Rosing and his team have found the nutrient-rich mud improves plant growth when used in farms. It also absorbs carbon dioxide from the air in the process.

Researchers from the University of Ghana were able to increase corn production by 30 percent using glacial rock flour. The flour decreased the effect of rain and heat on poor farmland.

The tiny size of the silt's particles is what allows plants more access to nutrients⁴, including potassium, calcium⁵ and silicon⁶ compared to normal, rocky farmland.

"We are the stage in this project where we definitely know that it works," Rosing said. "There are many barriers between this and a big scale industry, but the potential is definitely there."

Absorbing Carbon dioxide

The tiny size of the silt's particles also helps speed up a natural process in which rocks absorb carbon dioxide (CO2).

When the silt dissolves in rainwater and releases its nutrients, a chemical reaction occurs that absorbs carbon dioxide from the atmosphere. The silt is eventually deposited in the sea.

The idea of putting tiny rock in farmland is not new. But the method has gained more interest because of the discovery that it can absorb CO2.

"That realization⁷ has been a catalyst⁸ for a lot more research in this area," said David Beerling. He is a professor at the University of Sheffield and head author of a study on crushed basalt, a tiny volcanic⁹ rock.

The study found that spreading finely crushed basalt on fields, as well as helping¹⁰ crops to grow, removes CO2 from the atmosphere. And it does so at a cost about equal to other methods of carbon capture.

Such detailed¹¹ research has not been done for glacial rock flour. But tests by the scientists in Copenhagen found that one ton of glacial rock flour would accept between 250 and 300 kilograms of CO2 when applied¹² to fields. That may also permit farmers to sell that as carbon credits.

Commercial production

Greenland's new government hopes the silt can one day can help the economy as well as permit the country to move away from some kinds of mining.

"We don't need to blast off the top of a mountain or build a processing plant," Greenland's resources minister told possible investors¹³ in September.

Government officials will present the mineral at a mining meeting in Vancouver early next year, but say commercial mining and use could be years away.

The scientists at the University of Copenhagen and the University of Ghana say success could improve food security and economic inequality. Good farmland is not equally spread around the world.

Studies show that the best farmland, which is across parts of North America and Europe, was covered by ice during the last ice age. Just as in Greenland today, the thick layer of ice has made the soil healthier.

"In Northern Europe, we think the reason we're better off than the rest of the world is that we are so much smarter than everyone else. In fact, we just have better soil," Rosing said.

Words in This Story

deposit — n. an amount of something (such as sand, snow, or mud) that has formed or been left on a surface or area over a period of time

native — adj. born in a particular place

absorb — v. to take in (something, such as a liquid) in a natural or gradual way

dissolve — v. to mix with a liquid and become part of the liquid

catalyst — n. a substance that causes a chemical reaction to happen more quickly

blast — n. a mass of air that moves very quickly and forcefully

commercial — adj. related to or used in the buying and selling of goods and services

1 glaciers   

冰河，冰川( glacier的名词复数 )

参考例句：

• Glaciers gouged out valleys from the hills. 冰川把丘陵地带冲出一条条山谷。
• It has ice and snow glaciers, rainforests and beautiful mountains. 既有冰川，又有雨林和秀丽的山峰。 来自英语晨读30分（高一）

2 lessen   

vt.减少，减轻；缩小

参考例句：

• Regular exercise can help to lessen the pain.经常运动有助于减轻痛感。
• They've made great effort to lessen the noise of planes.他们尽力减小飞机的噪音。

3 silt   

n.淤泥，淤沙，粉砂层，泥沙层；vt.使淤塞；vi.被淤塞

参考例句：

• The lake was almost solid with silt and vegetation.湖里几乎快被淤泥和植物填满了。
• During the annual floods the river deposits its silt on the fields.每年河水泛滥时都会在田野上沉积一层淤泥。

4 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

5 calcium   

n.钙(化学符号Ca)

参考例句：

• We need calcium to make bones.我们需要钙来壮骨。
• Calcium is found most abundantly in milk.奶含钙最丰富。

6 silicon   

n.硅(旧名矽)

参考例句：

• This company pioneered the use of silicon chip.这家公司开创了使用硅片的方法。
• A chip is a piece of silicon about the size of a postage stamp.芯片就是一枚邮票大小的硅片。

7 realization   

n.实现；认识到，深刻了解

参考例句：

• We shall gladly lend every effort in our power toward its realization.我们将乐意为它的实现而竭尽全力。
• He came to the realization that he would never make a good teacher.他逐渐认识到自己永远不会成为好老师。

8 catalyst   

n.催化剂，造成变化的人或事

参考例句：

• A catalyst is a substance which speeds up a chemical reaction.催化剂是一种能加速化学反应的物质。
• The workers'demand for better conditions was a catalyst for social change.工人们要求改善工作条件促进了社会变革。

9 volcanic   

adj.火山的；象火山的；由火山引起的

参考例句：

• There have been several volcanic eruptions this year.今年火山爆发了好几次。
• Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。

10 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

11 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

12 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

13 investors   

n.投资者，出资者( investor的名词复数 )

参考例句：

• a con man who bilked investors out of millions of dollars 诈取投资者几百万元的骗子
• a cash bonanza for investors 投资者的赚钱机会