英語聽力文摘 English Digest 297：藻類生物燃料
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 dependence on fossil fuels to powercars, trucks, and even airplanes.
Algae has attracted attention because it is simple and economicalto 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 evenwastewater for a habitat.
The plant's highly-adapted photosynthesis process allows it to thriveanywhere that abundant sunshine can be found.
And even sunshine is optional for this versatile plant because scientists have discovered ways to grow algae in the dark using sugar as a food source.
To use algae as a replacement for fossil fuels, oil is extracted from the plant and developed into abiofuel that can be burned in diesel engines.
The yield produced from the algae has proven fargreater than other biofuels currently being developed.
For example, soy produces an averageyield of fifty gallons of biofuel per acre per year.
Canola, another common alternative, producesroughly 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 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!