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 produc
Plant Gas Scientists have been studying natural sources of methane(甲烷,沼气) for decades but hadn’t regarded plants as a produc
admin
2011-05-18
90
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 Planck 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.
To test whether plants are a source of methane, the scientists created______.
选项
A、a oxygen-free environment
B、an environment with the same concentration of oxygen as the Earth has
C、a carbon dioxide-free environment
D、an environment filled with the greenhouse gas
答案
B
解析
第三段第一句说,科学家使用密封的房间来做实验,房间里氧气的浓度与地球大气中的氧气浓度相仿。所以B句符合原文的意思,其他三个选择则不符合原文内容。
转载请注明原文地址:https://kaotiyun.com/show/RuLd777K
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
ASunshadeforthePlanetEvenwiththebestwillintheworld,reducingourcarbonemissionsisnotgoingtopreventglobal
MoreAboutAlzheimer’sDiseaseScientistshavedevelopedskinteststhatmaybeusedinthefuturetoidentifypeoplewith
HypertensionDrugsFoundtoCutRiskofStrokeAustraliandoctorsdeclaredMondaythatacocktailofsimpleantihypertensive
WomenwithAIDSForalongtimewomenwithHIVwereignoredbecausethefocuswastotallyonHIVmen.Thegaycommunitywas
FermiProblemOnaMondaymorninginJuly,theworld’sfirstatombombexplodedinNewMexicodesert.Fortysecondslater,t
FermiProblemOnaMondaymorninginJuly,theworld’sfirstatombombexplodedinNewMexicodesert.Fortysecondslater,t
HeartbeatofAmericaNewYork—theStatueofLiberty,theskyscrapers,thebeautifulshopsonFifthAvenueandthemanytheat
Thecityhasdecidedtodoawaywithalltheoldbuildingsinitscentre.
Thelastfewweekshavebeenenjoyable.
FemaleBullfightingItwasaunique,eye-catchingsight:anattractivewomaninashinybullfighter’ssuit,swordinhand,facin
随机试题
能加速混凝土早期强度发展的外加剂称为()。
作者的署名权、修改权、保护作品完整权的保护期不受限制。公民的作品,其发表权、著作财产权的保护期为作者终生及其死亡后________,截止于作者死亡后第50年的12月31日。法人或者其他组织的作品、著作权(署名权除外)由法人或者其他组织享有的职务作品,其发表
新生儿沐浴时的注意事项有()
男,51岁。近3年来出现关节炎症状和尿路结石,进食肉类食物时,病情加重。该患者发生的疾病涉及的代谢途径是
采用隧道激光断面仪对隧道总体尺寸进行检测时,曲线每20m、直线每40m检查一个断面。()
建设项目招标公告与投标邀请书上应当载明(),以及获取招标文件的办法。
下列关于会计内部监督基本要求的表述,错误的是()。
教学就是上课。
某省2016年上半年省内居民网络消费达1696.07亿元,同比增长45.13%。该省2015年上半年,省内居民网络消费额占2016年上半年的:
Intheworldofentertainment,TVtalkshowshaveundoubtedlyfloodedeveryinchofspaceondaytimetelevision.Andanyonewho
最新回复
(
0
)