Plant Gas
Scientists have been studying natural sources of methane for decades but hadnt regarded plants as a producer,notes Frank Keppler,a geochem[st at the Max Planck Institute for Nuclear Physics in Heidelberg,Germany1.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.
In its experiments,Kepplers team used sealed chambers that contained the same concentration of oxygen that Earths atmosphere has.They measured the amounts of methane that were released by both living plants;and dried plant material,such as fallen leaves.
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.
The new finding is an interesting observation, says Jennifer Y.King,a biogeochemist at the University of Minnesota in St.Paul3.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 plants influence,she notes.
1. What was scientists understanding of methane?
B It was not a greenhouse gas.
D It traps more heat than any other greenhouse gas.
A a oxygen-free environment.
C a carbon dioxide-free environment.
3. Which statement is true of the methane emissions of plants in the experiment?
B I.iving plants release less methane than dried plants at the same temperature.
D The higher the temperature,the greater the amount of methane emissions.
A Plants growing in soil release methane.
C Soil microbes consume methane.
初一年级英语作文:Teachers' Day
初一年级英语作文 满分作文必备短语句型精讲 as…as possible
初一年级英语作文 满分作文必备短语句型精讲 not as/so…as…
初一英语作文:英语的重要性
初一英语作文:A Summer Camp
初一年级英语作文:My Grandpas Birthday
初一英语作文:Good Neighbours
初一年级英语作文 满分作文必备短语句型精讲 It takes sb sometime to do sth.
初一年级英语作文:My Cat
初一年级英语作文 满分作文必备短语句型精讲 spend…on(in doing)sth
初一英语作文:我的存钱罐
初一年级英语作文:Time
初一年级英语作文:Watch TV
初一英语作文:我的同学
初一英语作文:Welcome to Our Village
初一年级英语作文 满分作文必备短语句型精讲 either…or…
初一英语作文:保持健康的方法
初一英语作文:An unforgettable friend
初一年级英语作文 How to Be Stronger
初一年级英语作文:My Happiest Day
初中英语满分作文必备短语与句型精讲
初一英语作文:A Good Librarian
初一年级英语作文:My City
初一英语作文:我家乡的四季
初一年级英语作文:Smoking
初一年级英语作文:How to Succeed?
初一英语作文:美国人的绘画生活
初一英语作文:新生活(New life)
初一英语作文:如何消度星期日
初一英语作文:我去日本旅行(My Trip to Japan)
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |