VOA标准英语2013--Bacteria Thrive on Ocean Plastic Debris

 

Bacteria Thrive on Ocean Plastic Debris¹

It takes about six weeks for a plastic bag or bottle to ride the surface currents from the U.S. East Coast to the Sargasso Sea, in the center of the North Atlantic. The area is a gyre, essentially² a big whirlpool that traps and swirls³ the debris which, unlike other types of trash in the ocean, never bio-degrades.

This is where Tracy Mincer⁴, a microbiologist with Woods Hole Oceanographic Institution, and colleagues from the Marine⁵ Biological Laboratory, joined students aboard a Sea Education Association vessel⁶ to sample plastic debris for microbes.  

“We hypothesized that the microbes on plastic were specifically interacting with it, rather than just a random⁷ association," Mincer said. "It’s not just flypaper that is just grabbing on to anything. Things are actually specifically interacting with plastic for a reason.”

The team skimmed the surface with fine nets, collecting confetti size bits of plastic. They analyzed⁸ the plastic with electron scanning tools and gene⁹ sequencing techniques. They found rich colonies of bacteria, including some that they hadn’t expected, which they called 'pit formers.'

“We were surprised when we saw microbes that appeared to be hydrolyzing [breaking down] the plastic and etching into it," said Mincer, "as well as just a whole other amazing ecosystem¹⁰ that was thriving on this plastic surface.”

The organisms in this plastisphere were different from those in the surrounding nutrient-poor water, indicating that the plastic acts as an artificial microbial reef, one that could harbor disease-causing pathogens and other harmful algal species.   

“It’s certainly possible. And a lot of time certain toxins¹¹ are oily in nature and they will absorb on to the plastic, but when the microbes interact with it they could be releasing those toxins off of the plastics,” Mincer said.

Hormonal¹² effects

Some of those additives¹³ are known to have hormonal effects in humans.  

More than 90 percent of the trash floating on the ocean surface is plastic. The largest of the planet's five gyre sites is the Great Pacific Garbage Patch, which is twice the size of Texas. Mincer says with so much plastic out there, it is important to know how it impacts marine species and by extension, people.  

“Fish are eating the plastic," Mincer said. "Are they picking up certain toxins from the plastic or not? And what does happen to plastic once it goes out into this environment? Does it eventually degrade into little tiny bits? And then what does it do?  Do the microbes make it heavier and make it sink quicker? Does it go away?  Is it a problem?”

The initial survey identified about 1,000 microbes that live on and interact with plastic. The next step is to sequence their genomes to get a better idea of whether or not they could be harmful pathogens.

1 debris   

n.瓦砾堆，废墟，碎片

参考例句：

• After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。
• Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上，导致蛀牙。

2 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。

3 swirls   

n.旋转( swirl的名词复数 )；卷状物；漩涡；尘旋v.旋转，打旋( swirl的第三人称单数 )

参考例句：

• Swirls of smoke rose through the trees. 树林中升起盘旋的青烟。 来自辞典例句
• On reaching the southeast corner of Himalaya-Tibet, It'swirls cyclonically across the Yunnan Plateau. 在到达喜马拉雅--西藏高原东南角处，它作气旋性转向越过云南高原。 来自辞典例句

4 mincer   

n.粉碎机

参考例句：

• With a household food mincer, one can cook many kinds of food for immediate consumption. 有了家用食品粉碎机，很多食品都可以现做现吃了。

5 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。

6 vessel   

n.船舶；容器，器皿；管，导管，血管

参考例句：

• The vessel is fully loaded with cargo for Shanghai.这艘船满载货物驶往上海。
• You should put the water into a vessel.你应该把水装入容器中。

7 random   

adj.随机的；任意的；n.偶然的(或随便的)行动

参考例句：

• The list is arranged in a random order.名单排列不分先后。
• On random inspection the meat was found to be bad.经抽查，发现肉变质了。

8 analyzed   

v.分析( analyze的过去式和过去分词 )；分解；解释；对…进行心理分析

参考例句：

• The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
• The young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程，因为对他来说，爱是个不可分析的迷。 来自《简明英汉词典》

9 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。

10 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

11 toxins   

n.毒素( toxin的名词复数 )

参考例句：

• The seas have been used as a receptacle for a range of industrial toxins. 海洋成了各种有毒工业废料的大容器。
• Most toxins are naturally excreted from the body. 大部分毒素被自然排出体外。 来自《简明英汉词典》

12 hormonal   

adj.激素的

参考例句：

• Some viral diseases are more severe during pregnancy, probably tecause of hormonal changes. 有些病毒病在妊娠期间比较严重，可能是由于激素变化引起的。
• She underwent surgical intervention and a subsequent short period of hormonal therapy. 他接受外科手术及随后短暂荷尔蒙治疗。

13 additives   

n.添加剂( additive的名词复数 )

参考例句：

• chemical additives in petrol 汽油中的化学添加剂
• It'says on the packet that these crisps contain no additives. 包装上说这些炸薯片不含添加剂。 来自《简明英汉词典》