Plant gas.You may have never heard of methane methane (mĕth`ān), CH4, colorless, odorless, gaseous saturated hydrocarbon; the simplest alkane. It is less dense than air, melts at −184°C;, and boils at −161.4°C;. , but there's a lot of it out there. Cows emit TO EMIT. To put out; to send forth, 2. The tenth section of the first article of the constitution, contains various prohibitions, among which is the following: No state shall emit bills of credit. the gas, which is produced by bacteria in their stomachs. Methane also wafts up from the wet soils in swamps and rice paddies, where methane-producing microbes live. Now, an international team of scientists has found another, unexpected natural source of methane: plants. 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 greenhouse gas n. Any of the atmospheric gases that contribute to the greenhouse effect. greenhouse gas , like carbon dioxide carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. . Gases such as methane and carbon dioxide trap heat in Earth's atmosphere “Air” redirects here. For other uses, see Air (disambiguation). Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly (by molar content/volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0. and contribute to global warming global warming, the gradual increase of the temperature of the earth's lower atmosphere as a result of the increase in greenhouse gases since the Industrial Revolution. . In their experiments, the scientists 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 measurements at temperatures ranging from 30 degrees Celsius (86 Fahrenheit) to 70 degrees C (158 F). At 30 degrees C, they found, a gram of dried material released up to 3 nanograms of methane per hour. (One nanogram nanogram /nano·gram/ (ng) (nan?o-gram) one billionth (10-9) of a gram. nan·o·gram n. Abbr. ng One billionth (10-9) of a gram. 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 material 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. Altogether, the world's plants produce more than 150 million metric tons of methane each year, the scientists estimate. That's 20 percent of all the methane that typically enters the atmosphere. Future tests will measure how much of an impact plant-produced methane actually has on the environment. http://www.sciencenewsforkids.org/articles/20060118/Note2.asp |
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