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MICROBIOLOGY
In the sediment below the waters of Namibia's Skeleton Coast-named for the stormtossed ships that litter the sea floor therescientists have made a dazzling find: a giant new species of bacterium, the world's largest, that grows as a string of pearly white globules. As reported on page 493. cells of Thiomargarita namibiensis, the "Sulfur pearl of Namibia," reach three-quarters of a millimeter in diameter-100 times larger than that of the average bacterium. "They were so large, at first we could not believe they were bacteria," says discoverer Heide Schulz, a microbiologist at the Max Planck Institute for Marine Microbiology in Bremen, Germany.
This oddball microbe consumes both sulfide and nitrate, linking the ecological cycles of these two key coastal compounds.
Although many bacteria utilize one or the other, few have been identified that rely on both. But it now seems that "this kind of metabolism is much more widespread than previously thought," says co-author Bo Barker Jorgensen of the Max Planck Institute. Other researchers note that such bacteria might one day help clean up coastal waters that have been polluted by excess nitrates from agricultural runoff.
Schulz found Thiomargarita while trying to determine whether an unusual species of sulfide-eating microbe...