with water ranging in temperature from 68 degrees F (20 degrees C) to 142 degrees F (61 degrees C). They threw the worms in. "What happened really kind of shocked us, which is they all very quickly moved when we imposed the thermal gradient," Girguis said. "They just picked up and went," he added. "It was like they were having a little conference" in the hotter water. The worms survived for as long as seven hours at 122 degrees F (50 degrees C), and would spend as long as 15 minutes at 131 degrees F (55 degrees C). Water of 140 degrees F (60 degrees C) killed them. These temperatures are far hotter than anything most animals can survive. Other researchers have found desert fire ants die at 131 degrees F (55 degrees C) and a hot tub, for instance, ranges from 100 degrees F (38 degrees C) to 105 degrees F (40 degrees C). Desert air is often hotter but water conducts heat much more efficiently than air does. Girguis said the experiment answered a key question about the physiology of the worms. The cells of complex animals all rely on structures called mitochondria, which provide power to the cells. Mitochondria start to break down at temperatures of 122 to 131 F (50 to 55 degrees C), Girguis said. The worms may skate on the borderlines of this limit but do not break it. They almost certainly have multiple other adaptations, he said, including heat-tolerant enzymes in their cells. --SP 23 51 Local Time 20 51 GMT
