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.
人教版五年级上册英语Unit 6第6节作业本答案
人教版五年级上册英语Unit 2第5节作业本答案
人教版五年级上册英语Unit 6第5节作业本答案
人教版五年级上册英语Unit 2第4节作业本答案
人教版五年级上册英语Unit 4第5节作业本答案
人教版四年级上册英语Unit 1用心想一想课前回顾同步导学与优化训练答案
人教版四年级上册英语Unit 1 Part A同步导学与优化训练答案
人教版五年级上册英语Recycle 1第4节作业本答案
人教版五年级上册英语Recycle 2第1节作业本答案
人教版五年级上册英语Unit 6第2节作业本答案
人教版五年级上册英语Recycle 1第1节作业本答案
人教版五年级上册英语Unit 2第6节作业本答案
人教版五年级上册英语Unit 4第6节作业本答案
人教版五年级上册英语Unit 2第2节作业本答案
人教版四年级上册英语Unit 1 Part C同步导学与优化训练答案
人教版五年级上册英语Unit 6第4节作业本答案
人教版五年级上册英语Recycle 2第4节作业本答案
人教版五年级上册英语Unit 3第5节作业本答案
人教版五年级上册英语Challenge 2作业本答案
人教版五年级上册英语Unit 5第4节作业本答案
人教版五年级上册英语Unit 4第1节作业本答案
人教版四年级上册英语Unit 2用心想一想课前回顾同步导学与优化训练答案
人教版五年级上册英语Unit 4第3节作业本答案
人教版五年级上册英语Unit 3第3节作业本答案
人教版五年级上册英语Unit 4第4节作业本答案
人教版五年级上册英语Unit 1第6节作业本答案
人教版五年级上册英语Unit 3第4节作业本答案
人教版五年级上册英语Unit 3第6节作业本答案
人教版五年级上册英语Unit 5第6节作业本答案
人教版五年级上册英语Unit 5第5节作业本答案
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |