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
95
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
Whilestillinitsearlystages,welfarereformhasalreadybeenjudgedagreatsuccessinmanystates,atleastUNisgettingp
Imagineaworldwithoutbrands.【R1】______Noraucousadvertising,nouglybillboards,andnoMcDonald’s.Yet,givenachanceand
InBritain,agreementsforinvitingandentertainingguestataweddingareusuallytheresponsibilityofthebride’sfamily.In
1.AccordingtotheWallStreetJournal,"Moreandmoreshoppersarebypassinghouseholdnamesforthecheaper,no-nameproducts
1.AccordingtotheWallStreetJournal,"Moreandmoreshoppersarebypassinghouseholdnamesforthecheaper,no-nameproducts
Itisnaturalforyoungpeopletobecriticaloftheirparentsattimesandtoblamethemforthemostofthemisunderstandings
1.Sharewareiscomputersoftwarethatisdistributedontheprinciplethatusercantryitbeforetheybuyit.Sharewareisnot
THETRAINJOURNEY0YouknowIwasgoingdowntoLondontostaywithmyfriend00Aliceduringtheholidays.Well,thetr
Thelittleboywassofascinatedbythemightyriverthathewouldspendhourssittingonitsbankandgazingatthepassingboa
Withimmenserelief,Istoppedrunning.
随机试题
创建型模式支持对象的创建,该模式允许在系统中创建对象,而不需要在代码中标识特定类的类型,这样用户就不需要编写大量、复杂的代码来初始化对象。在不指定具体类的情况下,____①____模式为创建一系列相关或相互依赖的对象提供了一个接口。____②____模式
如果我们早点动身,现在就不会在雨中走了。
患者,女,30岁。刷牙经常出血,临床诊断为牙龈炎,应建议她多长时间做一次洁治
安全验收评价报告应全面、概括地反映安全评价过程的全部工作,评价报告应包括①目的②概况③评价依据④危险、有害因素的辨识与分析⑤安全评价方法选择⑥评价单元的划分⑦安全对策措施建议⑧安全评价结论等内容。下列安全验收评价报告内容的顺序表述,正确的是()。
下列哪些属于行政许可()。
石油原油()
注册会计师应当评价已识别客观性的不利影响的重要程度并在必要时采取防范措施消除不利影响或将其降至可接受水平。以下有关防范措施中,不能降低不利影响的是()。
信息的编码、储存、提取方式和信息储存时间的长短是划分()的标准。
WestBerlinwastreatedasacityandstateoftheFederalRepublicofGermanyuntilthe______oftheGermanstatein1990,tho
A、He’sserious.B、He’scareless.C、He’skind.D、He’spolite.A本题考查事实细节。男士问“你觉得你的新老板怎样?”女士回答:“我不喜欢他,他太严肃。”只要在听录音时捕捉到关键信息tooserio
最新回复
(
0
)