密歇根新闻广播 小小树叶的腐烂竟反映了气候变化的信息

What do tiny pieces of decomposing¹ leaves have to do with climate change? It turns out they’re nitrous oxide² hot spots.

Nitrous oxide is a greenhouse gas that’s 300 times more potent³ than carbon dioxide.

Phil Robertson is a professor of ecosystem⁴ science at Michigan State University’s Kellogg Biological Station, and he's also with MSU's Department of Plant, Soil and Microbial Sciences.

He notes that nitrous oxide is produced naturally by microbes in soil.

“And we’ve known for a long time the nitrous oxide emissions⁵ from soil play a big role in the greenhouse gas content of the atmosphere, and we also now that human activity - especially farming - can affect nitrous oxide production by soils. But we haven’t really nailed down the microbial basis for where this happens in soil,” he says.

Until now.

Robertson, along with MSU professor Sasha Kravchenko and their team, discovered that miniscule pieces of decomposing leaves in the soil act like sponges to soak up water and provide the perfect microbial habitat for the bacteria that produce the nitrous oxide.

“The microbes just go to town. They love this high-water, carbon-rich environment,” he says.

An MRI for soil

So how did they do it? With microscopes and tomography, which Robertson says is like a small MRI unit, to examine small blocks of soil.

"We did this at the Argonne National Laboratory in Illinois, where they have a very powerful MRI scanner that's capable of penetrating⁶ soil. This is the kind of technology that we use in medicine to identify abnormalities in human physiology⁷."

Robertson says they can use this technology to create a 3D picture of the soil particles and their moisture content. Then they used gas sampling to determine the source of the nitrous oxide that was coming off.

He says next, people can work to figure out how to control the hot spots.

“And designing farming practices to minimize these emissions is perhaps a next step,” says Robertson. “So it basically gives us another important piece of information for the agronomists⁸ to use to design more climate-friendly cropping practices.”

The study was published in the journal Nature Geoscience.

1 decomposing   

腐烂( decompose的现在分词 )； （使）分解； 分解（某物质、光线等）

参考例句：

• The air was filled with the overpowering stench of decomposing vegetation. 空气中充满了令人难以忍受的腐烂植物的恶臭。
• Heat was obtained from decomposing manures and hot air flues. 靠肥料分解和烟道为植物提供热量。

2 oxide   

n.氧化物

参考例句：

• Oxide is usually seen in our daily life.在我们的日常生活中氧化物很常见。
• How can you get rid of this oxide coating?你们该怎样除去这些氧化皮？

3 potent   

adj.强有力的，有权势的；有效力的

参考例句：

• The medicine had a potent effect on your disease.这药物对你的病疗效很大。
• We must account of his potent influence.我们必须考虑他的强有力的影响。

4 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

5 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

6 penetrating   

adj.（声音）响亮的，尖锐的adj.（气味）刺激的adj.（思想）敏锐的，有洞察力的

参考例句：

• He had an extraordinarily penetrating gaze. 他的目光有股异乎寻常的洞察力。
• He examined the man with a penetrating gaze. 他以锐利的目光仔细观察了那个人。

7 physiology   

n.生理学，生理机能

参考例句：

• He bought a book about physiology.他买了一本生理学方面的书。
• He was awarded the Nobel Prize for achievements in physiology.他因生理学方面的建树而被授予诺贝尔奖。

8 agronomists   

n.农（艺）学家( agronomist的名词复数 )

参考例句：

• Agronomists are concerned with the production of crops for food, feed, and fibre. 农学工作者应学习食物、饲料和纤维作物的生产。 来自辞典例句
• Agronomists and farmers use the pictures to study crops. 农学家和农民利用图片来研究庄稼。 来自互联网