首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Plant Gas Scientists have been studying natural sources of methane (甲烷,沼气) for decades but hadn’t regarded plants as a produ
Plant Gas Scientists have been studying natural sources of methane (甲烷,沼气) for decades but hadn’t regarded plants as a produ
admin
2011-01-02
41
问题
Plant Gas
Scientists have been studying natural sources of methane (甲烷,沼气) for decades but hadn’t regarded plants as a producer, notes Frank Keppler, a geochemist(地球化学家) at the Max Planek Institute for Nuclear Physics in Heidelberg, Germany. Now Keppler and his colleagues find that plants, from grasses to trees, may also be sources of the greenhouse gas. This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.
Previously, researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes(微生物) need to be in environments without oxygen to produce methane. Methane is a greenhouse gas, like carbon dioxide. Gases such as methane and carbon dioxide trap heat in Earth’s atmosphere and contribute to global warming.
In its experiments, Keppler’s team used sealed chambers (室,房间;腔) that contained the same concentration of oxygen that Earth’s atmosphere has. They measured the amounts of methane that were released by both living plants and dried plant material, such as fallen leaves.
With the dried plants, the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C..At 30 degrees C., they found, a gram of dried plant material released up to 3 nanograms(微克) of methane per hour (One nanogram is a billionth of a gram. ). With every 10-degree rise in temperature, the amount of methane released each hour roughly doubled.
Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled (增加三倍) when living and dead plant was exposed to sunlight.
Because there was plenty of oxygen available, it’s unlikely that the types of bacteria( bacterium 的复数,细菌) that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions. That’s another strong sign that the gas came from the plants and not soil microbes.
The new finding is an "interesting observation," says Jennifer Y.King, a biogeochemist(生物地球化学家) at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane, they may prevent plant-produced methane from reaching the atmosphere. Field tests will be needed to assess the plant’s influence, she notes.
What was scientists’ understanding of methane?
选项
A、It was produced from plants.
B、It was not a greenhouse gas.
C、It was produced in oxygen-free environments.
D、It traps more heat than any other greenhouse gas.
答案
C
解析
短文的第一段和第二段都讲到,科学家过去曾经认为,沼气必须在无氧的环境中才能产生。注意作者用的是过去式:Most scientists assumed that…,They had assumed that….
转载请注明原文地址:https://kaotiyun.com/show/DNLd777K
本试题收录于:
职称英语理工类A级题库职称英语分类
0
职称英语理工类A级
职称英语
相关试题推荐
StepBackinTimeDoyouknowthatwelivealotlongernowthanthepeoplewhowerebornbeforeus?Onehundredyearsagot
Thepolarregionsaregenerallycoveredwithiceandsnow.
OntheTrialoftheHoneyBadgerOnarecentfieldtriptotheKalahariDesert,ateamofresearcherslearnalotmoreabout
A.showthatorganiccropsaresaferthanconventionalonesB.bespeciallytrainedC.improvesoilqualityD.poisonyouE.be
Thisequipmentcanproducevividimagesoftheorgansofthepatientfordoctorstoanalyze.
Babiescanlearnlanguageevenintheirsleep.ThethreevowelsmentionedinthisarticleareallFinnishsounds.
Itsoundsallwrong-drillingholesinapieceofwoodtomakeitmoreresistanttoknock.Butitworksbecausetheenergyfromt
Itsoundsallwrong-drillingholesinapieceofwoodtomakeitmoreresistanttoknock.Butitworksbecausetheenergyfromt
Itsoundsallwrong-drillingholesinapieceofwoodtomakeitmoreresistanttoknock.Butitworksbecausetheenergyfromt
High-TechWarfare(战争) Today,high-techwarfareisnolongeranabstractconcept,butarealissue. Technology______(51)ta
随机试题
梁实秋的《谈时间》是一篇()
一患者右膝部闭合性损伤,伤后右足不能主动向背侧伸展,其主要原因是
某病人得知自己已是肺癌晚期,终日哭泣、悲伤、想自杀,此时病人的心理状态属于
关于建筑物基础的埋置深度,下列表述哪项不正确?[2001年第120题][2003年第074题]
建设项目财务管理必须遵守的原则是()。
因为先有证券发行市场后有流通市场,且证券发行市场与流通市场各有自己的运行规律,所以流通市场的交易价格与发行市场无关。()
关于税法的效力,下列表述错误的是()。
根据个人所得税法律制度的规定,下列应按“工资、薪金所得”税目征收个人所得税的是()。
减少佣金、推迟交货或终止关系等属于()。
在有关占星术的一个电视节目中,调查员在社区里找到了20名出生在双子座并且愿意在一个关于性格测验的电视节目中接受采访的志愿者。测试给调查者个人的印象是:每一个志愿参加者都比一般的人更善于交际。由此断言,人出生的星座影响人的性格。以下哪项如果为真,最严重
最新回复
(
0
)