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
23
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.
Which statement is true of the methane emissions of plants in the experiment?
选项
A、The lower the temperature, the higher the amount of methane emissions.
B、Living plants releas less methane than dried plants at the same temperature.
C、When exposed to sunlight, plants stop releasing methane.
D、The higher the temperature, the greater the amount of methane emissions.
答案
D
解析
根据第四段和第一段的内容,只有D是正确的说法。温度提高沼气的释放量提高,有生命的植物释放的沼气远大于干植物的释放量,在阳光下,它们的沼气释放量是正常情况的三倍。
转载请注明原文地址:https://kaotiyun.com/show/PNLd777K
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
MergersThemostcommonkindofconsolidationtodayisthemerger.46Withthederegulationofnaturalgas,thenation’s
ScientistsDevelopWaysofDetectingHeartAttackGermanresearchershavecomeupwithanewgenerationofdefibrillators(除颤
ScientistsDevelopWaysofDetectingHeartAttackGermanresearchershavecomeupwithanewgenerationofdefibrillators(除颤
OntheTrialoftheHoneyBadgerOnarecentfieldtriptotheKalahariDesert,ateamofresearcherslearnalotmoreabout
OntheTrialoftheHoneyBadgerOnarecentfieldtriptotheKalahariDesert,ateamofresearcherslearnalotmoreabout
OntheTrialoftheHoneyBadgerOnarecentfieldtriptotheKalahariDesert,ateamofresearcherslearnalotmoreabout
JapaneseCarKeepsWatchforDrunkDriversAconceptcardevelopedbyJapanesecompanyNissanhasabreathalyzer-likedetect
Hecouldnottoleratetheextremesofheatinthedesert.
FDA;Human,AnimalWasteThreatensProduceThebiggestfoodsafetyriskforfreshfruitsandvegetablesastheyaregrown,p
Practicallyallspeciesofanimalscommunicateeitherthroughsoundsorthroughalargerepertoryofsoundlesscodes.
随机试题
肝细胞中,大部分AST存在于
口底、颌下和颈部的急性蜂窝织炎可并发
颜面部疖和疔的鉴别要点是()
城市地下雨污水管疏浚检查时,常会从井内冒出一种非常活跃并能置人于死地的高浓度气体是()。
大多数套期保值者持有的股票并不与指数结构一致,因此,在股指期货套期保值中通常都采用( )方法。
下列项目中,不属于货币资金的是()。
某社区修建了绿化带,但经常有丢弃的烟头和废纸等垃圾。对绿化带造成了一定的破坏。请你谈谈这个问题出现的原因以及解决的对策。
田汉(1898~1968),剧作家、作家、戏剧活动家。写作改编的戏曲剧本有()。
在一个小型互联网中,动态刷新路由器的路由表可以使用的协议为()。
在窗体上画一个名称为List1的列表框,然后编写如下程序:PrivateSubForm_Click()Fori=1To10Item="Item"&i:List1.AddItemItemNextiEndSub程序运行时,单击窗体,所完
最新回复
(
0
)