美国国家公共电台 NPR Surf And Turf: To Reduce Gas Emissions From Cows, Scientists Look To The Ocean

 

ARI SHAPIRO, HOST:

Livestock¹ is a major source of greenhouse gases around the world. Scientists have been trying to find ways to reduce emissions² from cows, and they think they might have found a solution in the ocean. NPR's Merrit Kennedy explains.

MERRIT KENNEDY, BYLINE³: There's a pen at University of California, Davis where scientists are closely observing 12 research cows. Each is known by a four-digit number, except for the friendliest one.

BREANNA ROQUE: We just call her Ginger⁴. She's the only one with a name.

KENNEDY: When cows like Ginger burp, out from their gut⁵ comes a lot of methane⁶. It's a potent⁷ greenhouse gas, and livestock is one of the largest methane emitters in the U.S. These scientists are trying to reduce the emissions by tweaking the cow's diet. On this morning, graduate student Breanna Roque is mixing up breakfast for the research cows, and she's adding a secret ingredient.

ROQUE: So I'll sprinkle it in. I'll kind of rub it together with the hay, mix it around, and then we actually come through and pitchfork the whole ration⁸.

KENNEDY: We'll get back to what Roque is adding in a minute, but first, why is it that cows emit methane? Animal science professor Ermias Kebreab, who is leading the experiment, says that the chemical reaction happens in the first chamber⁹ of the cow's four-part stomach. It's actually microbes living in the stomach that produce the methane, kind of like how yeast¹⁰ produces carbon dioxide in beer.

ERMIAS KEBREAB: It's a natural process of fermentation.

KENNEDY: The cows burp that methane out into the atmosphere. He says belches¹¹ are a bigger problem than farts.

KEBREAB: Over 95 percent actually is from the mouth, from the front end of the cow.

KENNEDY: Which brings us back to that secret ingredient. What is it? Seaweed. Kebreab says they think seaweed has a chemical in it that can keep down methane levels in a cow's gut. To test it, they're feeding cows different amounts.

UNIDENTIFIED PERSON: Coming out now.

KEBREAB: Yep. There they are.

KENNEDY: The cows lumber¹² up, each heading to its own specially¹³ prepared meal. Some cows don't like the salty taste of seaweed, so Roque added a little bit of molasses, too, which they seem to appreciate. To test whether the seaweed is working, the cows take a methane breathalyzer test at least three times a day. When they stick their heads in a machine that measures the gases in their breath, they get a cow cookie.

ROQUE: Well, when it has to do with feed, they can be trained (laughter).

KENNEDY: Kebreab says they noticed a difference in emissions right away.

KEBREAB: And the results are almost immediate¹⁴. Like, you give them this today. The next day, you see the reduction.

KENNEDY: And the drop in methane was even more than they expected. He remembers the first numbers coming in.

KEBREAB: When Breanna was sending me those results, I was like, are you sure?

KENNEDY: Their experiment found that the high dose of seaweed reduced methane production by more than half.

KEBREAB: There's no doubt. There's - it's quite a dramatic reduction in methane emissions.

KENNEDY: But a dramatic reduction in emissions wouldn't do much good if it changed the taste of the cow's milk. Most people aren't looking for a salty, umami twist in their milkshakes, so researchers conducted another experiment. They brought in 25 panelists for a blind taste test who said the milk tasted normal. The relieved research team celebrated¹⁵ and made ice cream. It was also apparently¹⁶ delicious, but there's a long way to go.

The scientists are analyzing¹⁷ whether the seaweed changes the nutritional¹⁸ content of milk. They're also planning an experiment with beef cattle instead of dairy. And if all goes well, scientists and the livestock industry will have a new puzzle. What's the best way to grow a whole lot of seaweed? Merrit Kennedy, NPR News, Davis, Calif.

1 livestock   

n.家畜，牲畜

参考例句：

• Both men and livestock are flourishing.人畜两旺。
• The heavy rains and flooding killed scores of livestock.暴雨和大水淹死了许多牲口。

2 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

3 byline   

n.署名；v.署名

参考例句：

• His byline was absent as well.他的署名也不见了。
• We wish to thank the author of this article which carries no byline.我们要感谢这篇文章的那位没有署名的作者。

4 ginger   

n.姜，精力，淡赤黄色；adj.淡赤黄色的；vt.使活泼，使有生气

参考例句：

• There is no ginger in the young man.这个年轻人没有精神。
• Ginger shall be hot in the mouth.生姜吃到嘴里总是辣的。

5 gut   

n.[pl.]胆量；内脏；adj.本能的；vt.取出内脏

参考例句：

• It is not always necessary to gut the fish prior to freezing.冷冻鱼之前并不总是需要先把内脏掏空。
• My immediate gut feeling was to refuse.我本能的直接反应是拒绝。

6 methane   

n.甲烷，沼气

参考例句：

• The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
• Methane may have extraterrestrial significance.甲烷具有星际意义。

7 potent   

adj.强有力的，有权势的；有效力的

参考例句：

• The medicine had a potent effect on your disease.这药物对你的病疗效很大。
• We must account of his potent influence.我们必须考虑他的强有力的影响。

8 ration   

n.定量(pl.)给养，口粮；vt.定量供应

参考例句：

• The country cut the bread ration last year.那个国家去年削减面包配给量。
• We have to ration the water.我们必须限量用水。

9 chamber   

n.房间，寝室；会议厅；议院；会所

参考例句：

• For many,the dentist's surgery remains a torture chamber.对许多人来说，牙医的治疗室一直是间受刑室。
• The chamber was ablaze with light.会议厅里灯火辉煌。

10 yeast   

n.酵母；酵母片；泡沫；v.发酵；起泡沫

参考例句：

• Yeast can be used in making beer and bread.酵母可用于酿啤酒和发面包。
• The yeast began to work.酵母开始发酵。

11 belches   

n.嗳气( belch的名词复数 )；喷吐；喷出物v.打嗝( belch的第三人称单数 )；喷出，吐出；打（嗝）；嗳（气）

参考例句：

• A volcano belches smoke and ashes. 火山喷出黑烟和灰土。 来自《现代英汉综合大词典》
• A volcano belches forth smoke and ashes. 火山喷出烟和尘埃。 来自互联网

12 lumber   

n.木材，木料；v.以破旧东西堆满；伐木；笨重移动

参考例句：

• The truck was sent to carry lumber.卡车被派出去运木材。
• They slapped together a cabin out of old lumber.他们利用旧木料草草地盖起了一间小屋。

13 specially   

adv.特定地；特殊地；明确地

参考例句：

• They are specially packaged so that they stack easily.它们经过特别包装以便于堆放。
• The machine was designed specially for demolishing old buildings.这种机器是专为拆毁旧楼房而设计的。

14 immediate   

adj.立即的；直接的，最接近的；紧靠的

参考例句：

• His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
• We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。

15 celebrated   

adj.有名的，声誉卓著的

参考例句：

• He was soon one of the most celebrated young painters in England.不久他就成了英格兰最负盛名的年轻画家之一。
• The celebrated violinist was mobbed by the audience.观众团团围住了这位著名的小提琴演奏家。

16 apparently   

adv.显然地；表面上，似乎

参考例句：

• An apparently blind alley leads suddenly into an open space.山穷水尽，豁然开朗。
• He was apparently much surprised at the news.他对那个消息显然感到十分惊异。

17 analyzing   

v.分析；分析( analyze的现在分词 )；分解；解释；对…进行心理分析n.分析

参考例句：

• Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据，暴露出的问题甚至更大。 来自辞典例句
• He undoubtedly was not far off the mark in analyzing its predictions. 当然，他对其预测所作的分析倒也八九不离十。 来自辞典例句

18 nutritional   

adj.营养的，滋养的

参考例句：

• A diet lacking in nutritional value will not keep a person healthy.缺乏营养价值的饮食不能维持人的健康。
• The labels on food products give a lot of information about their nutritional content.食品上的标签提供很多关于营养成分的信息。