VOA慢速英语 2008 1202a（在线收听）
The search for new fuels has led some researchers to algae. Algae is a name for thousands of different organisms. They include single-celled plants as well as kelp and other large plants.
 |
| Blue-green algae earlier this year in China |
Kenneth Bruland is an ocean sciences professor at the University of California, Santa Cruz. He says many experts also consider plant-like bacteria to be a form of algae. These bacteria make food from the sun like plants do.
Algae grow quickly and some contain a lot of oils. Most algae-to-energy researchers are growing algae in huge tanks. But one company, Blue Marble Energy in Seattle, Washington, uses algae already growing along coastlines. Workers pump it into bags on a boat. They have to be careful not to suck up young fish or other small creatures.
Blue Marble says its work could help prevent harmful algae blooms. A bloom is when a dense area of algae forms and spreads. Some blooms can harm people, animals or the environment.
Warmer water can cause blooms, and some scientists think global warming is adding to an increase in large ones. Nutrients from sewage and agricultural fertilizers also help algae grow.
Blue Marble is a start-up company with private investors. It also has a contract with Washington state to collect the algae called ulva, or sea lettuce, in parts of Seattle's Puget Sound waterway. In Puget Sound, big blooms of sea lettuce often break down in Dumas Bay. This process of rotting uses up oxygen and kills marine life. And when the sea lettuce washes up on the beach, it smells terrible.
Blue Marble President Kelly Ogilvie says his company has collected almost four thousand kilos of algae in two harvests. The next step is to use bacteria to break down the algae into natural gas and different chemicals. Most companies doing algae-to-energy research are creating liquid biofuels for cars or airplanes.
But some people have concerns about harvesting wild algae. University of Washington researcher Kevin Britton-Simmons says removing the algae does not solve the problem. He says keeping fertilizer and other pollutants out of the water would prevent a lot of unnatural blooms.
He also says it is difficult to tell the difference between natural algae blooms and those caused by human activity. He says removing natural blooms would remove valuable food for marine life.
And that's the VOA Special English AGRICULTURE Report. I'm Steve Ember