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
60
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.
What is the beneficial point of some microbes consuming plant-produced methane?
选项
A、Methane becomes less poisonous.
B、Methane is turned into a fertilizer.
C、Less methane reaches the atmosphere.
D、Air becomes cleaner.
答案
C
解析
最后一段的第二句可以找到本题的答案。
转载请注明原文地址:https://www.kaotiyun.com/show/JuLd777K
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
DevelopmentinNewspaperOrganizationOneofthemostimportantdevelopmentsinnewspaperorganizationduringthefirstpart
A.becostlyB.harmfulC.savealifeD.stillopentodebateE.reducetheriskofradiationtriggeringacancerF.reducedto
MoreAboutAlzheimer’sDiseaseScientistshavedevelopedskinteststhatmaybeusedinthefuturetoidentifypeoplewith
DoubleEffectTheSupremeCourt’sdecisionsonphysician-assistedsuicidecarryimportantimplicationsforhowmedicinesee
CarMaintenanceOnceitwasconsideredgoodpracticetoletthecarengineidleaminuteortwofollowingcoldstarts.Todaywit
ManandComputerWhatmakespeopledifferentfromcomputerprograms?Whatisthemissingelementthatourtheoriesdon’tyet(51)
AdaptationofLivingThingsCertainanimalsandplantsdevelopcharacteristicsthathelpthemcopewiththeirenvironmentbette
Idon’tfeelsecurewhenIamaloneinthehouse.
TheMagicofSoundMusicisoneofthemostbeautifulformsofartisticexpressionseverinvented.Inmoviesandplays,musi
TheindustrialrevolutionmodifiedthewholestructureofEnglishsociety.
随机试题
穿无菌手术衣的方法是
产妇,顺产后3个月,欲选择放置宫内节育器避孕。护士告知最适宜的放置时间是
男性,62岁,发热、咳嗽、口腔溃疡、皮肤有大片淤斑;血红蛋白90g/L,白细胞10×109/L,中性粒细胞0.86,淋巴细胞0.21,未见幼稚细胞,血小板25×109/L,凝血酶原时间15s(对照组12s),血浆鱼精蛋白副凝试验显弱阳性。最可能的诊断是
形成垂直食物嵌塞最常见的原因是
简述民事行为形式的概念和分类。
国家工作人员利用职务上的便利,侵吞、窃取、骗取或者以其他手段占有公共财物的行为称为()。
下列各选项中,属于狭义的守法范畴的是
在SQL语句中,用动词______来删除表。
编写如下事件过程;PrivateSubForm_MouseDown(ButtonAsInteger,ShiftAsInteger,XASSingle,YAsSingle)IfShif=6AndBu
A、Achangeinthenatureofreading.B、Anincreaseinthenumberofbooks.C、Achangeinthestatusofeducatedpeople.D、Aninc
最新回复
(
0
)