Microbes


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Dr. Eric Wommack, a University of Delaware researcher, is studying one of the most mysterious organisms found in the ocean: marine viruses.

While many of us associate "virus" only with "illness," Dr. Wommack says viruses can help scientists mine a treasure trove of information about how cells work.

"The wonderful thing about viruses is that they carry around DNA," he says. "Outside of a host cell, they are inert. But once a virus infects a host, whether that host is a bacterium or a human being, that virus knows how to exploit the organism's cells. So we can learn a lot about how a cell works from viruses."

Dr. Wommack has designed a special filtration system to capture the tiny viruses in vent water. Their average size is only 60 nanometers, which is 60 millionths of a centimeter or 23 millionths of an inch! Once the "bugs" are caught, he will use an electron microscope to examine them, characterize them by shape, and count them.

"Viruses outnumber other organisms by a factor of 10 in marine communities," he says. "So they're definitely an important part of how the ecosystem functions. I'm really excited about studying viruses at the vents. Vent communities consist of especially unique organisms," he notes. "If the hosts are unusual, their viruses will be as well."

Dr. Wommack is shown with the Large Volume Water Sampler (LVWS) he deployed during Extreme 2001 to collect large volumes of vent water (and hopefully, viruses).The video clip shows Alvin releasing a lever on the LVWS to begin water collection. Explore the Daily Journals from Extreme 2001 to find out what happened to the first LVWS. A new LVWS will be deployed during Extreme 2003.

Magnified view of vent bacteria on the surface of pyrite. The cylinder-shaped microbes are 4 microns long.

Scientists are particularly interested in vent bacteria because these primitive microbes can withstand high temperature and pressure, giving them many valuable uses in industry. For example, some bacteria can convert harmful chemicals to safer forms, making them ideal for cleaning up oil spills and hazardous waste.

Scientists are also curious about the deep sea's tiniest life because these organisms are among the oldest on Earth. In fact, an ancient life form — Archaea ("ark-ee-uh") — has been found at vent sites. Previously, these microscopic organisms had been discovered in another "extreme environment": hot springs in Yellowstone Park.

Some astrobiologists speculate that if there is life on other planets, it might be vent bacteria. Europa, one of Jupiter's moons, is covered in ice. Recent findings suggest that portions of the ice move, which is strong evidence that liquid water lies beneath it. The water may be maintained in its liquid state by hydrothermal vents. If vents exist on Europa, vent bacteria might live there, too!

Are hydrothermal vents home to the closest relatives of the oldest life on Earth? Using this electrode analyzer, a kind of "underwater snooper" built by University of Delaware scientists and housed in a wand on the submersible Alvin, researchers can test the chemistry of vent water to determine why certain organisms live where they do. They may also use the tool to search for useful microbes. To find out more,