英语听力文摘 English Digest 297、藻类生物燃料

　　Algae¹ Biofuel
作为不依赖于化石资源的燃料，生物燃料逐渐得到普遍认可。但在应用上，使用高等植物的现有手段还存在极限。其原因在于单位面积的收获量较小，并且还会浪费珍贵的水资源。作为解决之策，业界开始开发使用藻类的生物燃料。这样的话，不仅单位面积的收获量可达到现有手段的3～40倍，而且基本上不用水。不过，要想实用化，今后还必须要降低成本，不断摸索与吸收CO2相结合的方法。

　　If you’re like many people, when you think of algae you picture the unsightly green film that forms on neglected swimming pools and fish tanks.
Scientists, however, have made some discoveries that might change the way you think about this common plant.
Researchers are working on ways to use algae to reduce our dependence² on fossil fuels to power cars, trucks, and even airplanes. Algae has attracted attention because it is simple and economical to grow and carries fewer financial and environmental costs when compared to other alternatives.
Algae needs only water to grow, and can use fresh water, salt water, marshlands, and even wastewater for a habitat. The plant’s highly-adapted photosynthesis³ process allows it to thrive anywhere that abundant sunshine can be found. And even sunshine is optional for this versatile⁴ plant because scientists have discovered ways to grow algae in the dark using sugar as a food source.
To use algae as a replacement⁵ for fossil fuels, oil is extracted from the plant and developed into a biofuel that can be burned in diesel⁶ engines. The yield produced from the algae has proven far greater than other biofuels currently being developed. For example, soy produces an average yield of fifty gallons of biofuel per acre per year. Canola, another common alternative, produces roughly 130 gallons of biofuel per acre per year. In contrast, scientists have found that algae can produce up to 4,000 gallons of biofuel per acre per year.
In addition, because algae can be grown on water rather than land and without fertilizers, it may prove to be a more efficient and (1)environmentally sound alternative to the biofuels in use today. In the future, then, when you see algae you might think about more than just pond scum!
译文：
如许多人一样 ，当你想到藻类的时候，你会在脑海中即刻闪现出在无人问津的游泳池和鱼池里表面覆盖着一层难看的绿膜的画面。
然而科学家的发现却可以改变你对这种普通植物的看法。
研究人员正致力于如何利用藻类来减少我们对用化石燃料发动小车，卡车甚至飞机的依赖。藻类会引起科学家们的注意是因为相对于其它可选择的燃料来说，种植藻类更简单，经济，并且花费的财政和环境成本较少。
只要有水藻类就可以存活，它可以在淡水，咸水，沼泽地，甚至污水中生长。该植物高度适应的光合作用过程让其在任何阳光充足的地方都能茁壮成长。甚是阳光也只是一个可选择的条件，因为科学家们发现通过把糖作为食物来源也可以在黑暗中种植藻类。
若用藻类代替化石燃料，油就会从植物中提取出来，并被加工为可以在柴油机中燃烧的生物燃料。藻类的产量大大高于目前正在开发的其他生物燃料。例如，大豆平均每年每英亩可生产五十加仑的生物燃料。菜籽，另一种常见的替代品，平均每年每英亩大约可生产130加仑。与此相反，科学家们发现藻类平均每年每英亩可生产达4000加仑。
此外，藻类可以在水中而不是陆地上生长，也不需要施肥。因此可以证明目前在使用的生物燃料中它是更有效更环保的替代品。未来，当你看到藻类的时候你或许想到的不仅仅是“池塘败类”。
Notes:
(1)environmentally sound对环境无害的
Voluntary offset⁷ programs, however, are not regulated, so consumers cannot be sure that they are investing in environmentally sound projects.
然而，志愿性的抵消计画并未受到管理，因此消费者无法确定他们投资的是保护环境的计画。

1 algae   

n.水藻，海藻

参考例句：

• Most algae live in water.多数藻类生长在水中。
• Algae grow and spread quickly in the lake.湖中水藻滋蔓。

2 dependence   

n.依靠，依赖；信任，信赖；隶属

参考例句：

• Doctors keep trying to break her dependence of the drug.医生们尽力使她戒除毒瘾。
• He was freed from financial dependence on his parents.他在经济上摆脱了对父母的依赖。

3 photosynthesis   

n.光合作用

参考例句：

• In apple trees photosynthesis occurs almost exclusively in the leaves.苹果树的光合作用几乎只发生在叶内。
• Chloroplasts are the structures in which photosynthesis happens.叶绿体就是光合作用发生的地方。

4 versatile   

adj.通用的，万用的；多才多艺的，多方面的

参考例句：

• A versatile person is often good at a number of different things.多才多艺的人通常擅长许多种不同的事情。
• He had been one of the game's most versatile athletes.他是这项运动中技术最全面的运动员之一。

5 replacement   

n.取代，替换，交换；替代品，代用品

参考例句：

• We are hard put to find a replacement for our assistant.我们很难找到一个人来代替我们的助手。
• They put all the students through the replacement examination.他们让所有的学生参加分班考试。

6 diesel   

n.柴油发动机，内燃机

参考例句：

• We experimented with diesel engines to drive the pumps.我们试着用柴油机来带动水泵。
• My tractor operates on diesel oil.我的那台拖拉机用柴油开动。

7 offset   

n.分支，补偿；v.抵消，补偿

参考例句：

• Their wage increases would be offset by higher prices.他们增加的工资会被物价上涨所抵消。
• He put up his prices to offset the increased cost of materials.他提高了售价以补偿材料成本的增加。