VOA慢速英语2018--宝石中的隧道可能是生命的标志

Tunnels in Gemstone Might Be Sign of Life

Life has found a way to survive in some of the most extreme conditions in existence. Now, scientists believe they might have found a new habitat for microscopic¹ organisms inside a mineral substance called garnet.

Garnet is a gemstone that comes in many colors, but is most commonly a clear, deep red color.

Recent research found strangely shaped markings inside garnet stones from Thailand. The researchers discovered that fatty acid had collected in the markings. This suggests that an extremely small organism, or microbe, dug the markings into the garnet.

Magnus Ivarsson is the lead researcher on the study. He is with the University of Southern Denmark. He told VOA that the research started with a Thai exchange student named Bongkot Phichaikamjorwut, who was studying the qualities of several pieces of garnet.

The student noticed the strange markings, described as tunnels. These tunnels divided and changed directions. They were unlike the markings caused by environmental damage that she had observed before.

So the student asked Ivarsson for help.

Ivarsson said, “When I first saw these structures, these tunnels, I was sort of intrigued² by the complexity³ of them.”

He added that he had studied other microbial markings in minerals before, but never anything with such complexity.

Garnet is an unexpected habitat for microbes because of how hard the stone is. In fact, Ivarsson suggests that garnet is the hardest mineral ever discovered to have markings created by microbes.

“Who knows what we’ll find next,” he added, “maybe a diamond bored by microbes. Who knows?

Researchers, however, note that no living organisms were discovered within the gemstones. Dawn Cardace is a geosciences researcher at the University of Rhode Island in the United States. She says the study did not find any genetic⁴ material, or DNA⁵, of the organisms.

But she says that is probably because the researchers would need to examine at least 1,000 garnet gemstones to collect any DNA.

The researchers depended on several technologies to make their findings. They used high-powered microscopes to make three-dimensional maps of the tunnels, which are narrower than a human hair.

The scientists centered their attention on how the tunnels spread and changed directions, as well as the places where the tunnels came together.

Environmental damage can cause breaks in hard materials. But Ivarsson says natural processes cannot explain the complexity of the tunnels his team observed.

To demonstrate that microbes likely created the tunnels, the researchers had to examine the inside of the boreholes.

Ivarsson told VOA, “The organic content tells us that there’s been life living in there.” In fact, the researchers identified organic substances common among bacteria and fungi⁶.

The garnets from the study came from the soil in a river near Chiang Mai, Thailand. Ivarsson and his team compared the biological material found in them to other minerals found in the same area, including quartz⁷ and hematite. None of the comparable stones showed signs of fatty acids. This suggests that the biological material was unique to the garnet tunnels. Ivarrson says that researchers at least know that biology was involved.

Ivarsson and his team also examined Thai garnets from river soil and from granite⁸ rock formations further down the river.

He explains: “When we studied these garnets in the granite, we could see that there were no tunnels. But when we looked at the garnets further down the river, we could see that these tunnels structures had evolved. So, something happened along the way… in the river system."

Shane McClure is the international director of colored stones at the Gemological Institute of America. He says that such changes to the garnets can decrease the value of the stones. One or two small tunnels, he says, do not make a major difference in value.

But he adds if there are many visible tunnels, the value of the gemstone may be greatly affected⁹.

The gemstones might not be usable for costly¹⁰ jewelry¹¹. But the stones do demonstrate that life finds a way in all sorts of unexpected places.

Ivarsson said of the discovery, "When we look for life on Mars, we need to know what to look for. And this … is definitely interesting in the search for life on Mars or any type of extreme environment."

I’m Alice Bryant. And I’m Pete Musto.

Words in This Story

habitat – n. the place or type of place where a plant or animal naturally or normally lives or grows

gemstone – n. a stone that can be used in jewelry when it is cut and polished

tunnel(s) – n. a passage that goes under the ground or through a hill or other material

intrigued – v. made to want to know more about something

bore(d) – v. to make a hole or tunnel in something with a tool or by digging

three-dimensional – adj. having or seeming to have length, width, and depth

fungi – n. a group of living things, such as molds, mushrooms, or yeasts¹², that often look like plants but have no flowers and that live on dead or decaying things

unique to – adj. belonging to or connected with only one particular thing, place, or person

evolve(d) – v. to change or develop slowly often into a better, more complex, or more advanced state

visible – adj. able to be seen

1 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。

2 intrigued   

adj.好奇的，被迷住了的v.搞阴谋诡计(intrigue的过去式)；激起…的兴趣或好奇心；“intrigue”的过去式和过去分词

参考例句：

• You've really intrigued me—tell me more! 你说的真有意思—再给我讲一些吧！
• He was intrigued by her story. 他被她的故事迷住了。

3 complexity   

n.复杂(性)，复杂的事物

参考例句：

• Only now did he understand the full complexity of the problem.直到现在他才明白这一问题的全部复杂性。
• The complexity of the road map puzzled me.错综复杂的公路图把我搞糊涂了。

4 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。

5 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。

6 fungi   

n.真菌，霉菌

参考例句：

• Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
• The lawn was covered with fungi.草地上到处都是蘑菇。

7 quartz   

n.石英

参考例句：

• There is a great deal quartz in those mountains.那些山里蕴藏着大量石英。
• The quartz watch keeps good time.石英表走时准。

8 granite   

adj.花岗岩，花岗石

参考例句：

• They squared a block of granite.他们把一块花岗岩加工成四方形。
• The granite overlies the older rocks.花岗岩躺在磨损的岩石上面。

9 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

10 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

11 jewelry   

n.（jewllery）（总称）珠宝

参考例句：

• The burglars walked off with all my jewelry.夜盗偷走了我的全部珠宝。
• Jewelry and lace are mostly feminine belongings.珠宝和花边多数是女性用品。

12 yeasts   

酵母( yeast的名词复数 )； 酵母菌； 发面饼； 发酵粉

参考例句：

• The basidiospores proliperate in a manner comparable to the multiplication of yeasts. 担孢子以一种可与酵母繁殖相比拟的方式进行增殖。
• Wine yeasts can grow in sweet wines even after bottling. 装瓶以后葡萄酒酵母也能在甜葡萄酒中生长。