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 for decades but hadn’t regarded plants as a producer, not
Plant Gas Scientists have been studying natural sources of methane for decades but hadn’t regarded plants as a producer, not
admin
2013-09-25
40
问题
Plant Gas
Scientists have been studying natural sources of methane for decades but hadn’t regarded plants as a producer, notes Frank Keppler.a geochemist 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 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 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 ℃ elsius to 70 degrees℃. At 30 degrees ℃ , they found, a gram of dried plant material released up to 3 nanograms 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 when living and dead plant was exposed to sunlight.
Because there was plenty of oxygen available, it’s unlikely that the types of bacteria 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 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
转载请注明原文地址:https://kaotiyun.com/show/fN1d777K
本试题收录于:
职称英语卫生类C级题库职称英语分类
0
职称英语卫生类C级
职称英语
相关试题推荐
A、 B、 C、 B
Youareaskedtowriteacompositioninwhichyougiveyourownopinionsonthefollowingtopic:
Agreatnumberofpeoplethinkthatthosewithuniversityeducationshouldgethigherpaythanthosewithout,fortheybelievet
OnJune12thyoureceivedyourorderfromacompanybutitisashamethatthecompanymissedoneitemyouordered.Itisa13
Computerpeopletalkalotabouttheneedforotherpeopletobecome"computer-literate",inotherwords,tolearntounderstand
Facialexpressionscarrymeaning,determinedbycontextsandrelationships.【R1】______Awoman’ssmileatapolicemanwhoisabou
ItiscommonlybelievedintheUnitedStatesthatschooliswherepeoplegotogetaneducation.Nevertheless,ithasbeensaid
IntheUnitedStates,itisimportanttobepunctualforanappointment,aclass,ameeting,etc.Thismaynotbetrueinallco
1.Mostyoungpeopleenjoysomeformsofphysicalactivity.Itmaybewalking,cyclingorswimming,orinwinter,skatingorski
Couldyouimaginehavingacuthealalmostovernight(一夜之情)?ScientistsattheUniversityofCaliforniainSanFranciscohaveiso
随机试题
身体各部位皮肤渗透性的大小为
设计合同中约定的费用为估算设计费,需按批准的()核算设计费。
道路工程施工时,路堤填料优先采用()。[2007年、2012年真题]
下列不属于利率的一般形式的是()
下列各项中,实行一审终审制度的有()。
根据《道路交通安全法》有关规定,下列选项中表述不正确的是()。
地震是地球上的主要自然灾害之一。下列关于地震的说法,错误的是:
我国《民法通则》第五十四条规定:“民事法律行为是公民或者法人设立、变更、终止民事权利和民事义务的合法行为。”请问:民事法律行为对民事法律关系的影响是什么?
Nuclearpowerhasbecomeanimportantsourceofenergyinseveralcountries,especiallyinEuropeandJapan.Nuclearpowersuppl
Peoplecanlosetheirhearingatanyagebeforetheyareborn,asinfants,duringchildhood,oras【C1】______.Eachageofonset
最新回复
(
0
)