英语听力文摘 English Digest 524、闪电有助于肥沃土壤！

 　　Lightning Helps Fertilize¹ The Soil

 

　　Our bodies need protein, and proteins contain nitrogen. The air we breathe has plenty of nitrogen to satisfy our needs. But—that nitrogen is not available to us directly from the air. The only way we can get nitrogen is from the plants we eat, or from the animals we eat that eat the plants.

 

　　Here’s The Problem：

 

　　A nitrogenmolecule in the air consists of two atoms which are held together very tightly. In order for us to absorb nitrogen, the two atoms must be separated. But the two atoms are held together so tightly that our body chemistry does not have enough energy to process them.

 

　　This is where lightning comes in. Obviously we don’t have to be struck by lighting² in order to satisfy our need for nitrogen!

 

　　However, in a thunderstorm there is enough electrical energy in lightning to separate the nitrogen atoms in the air. Once the atoms are separated they can fall to earth with rain water, and combine with minerals in the soil to form nitrates, a type of fertilizer.

 

　　The nitrogen-containing nitrates in the soil are absorbed by the plants, and when we eat the plants or the animals which eat the plants, we get the nitrogen in a form which our bodies can use.

 

　　So, in addition to providing a spectacular light show, and scaring us to death, lightning also helps fertilize the soil.

1 fertilize   

v.使受精，施肥于，使肥沃

参考例句：

• Fertilizer is a substance put on land to fertilize it.肥料是施在地里使之肥沃的物质。
• Reading will fertilize his vocabulary.阅读会丰富他的词汇。

2 lighting   

n.照明，光线的明暗，舞台灯光

参考例句：

• The gas lamp gradually lost ground to electric lighting.煤气灯逐渐为电灯所代替。
• The lighting in that restaurant is soft and romantic.那个餐馆照明柔和而且浪漫。