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By Carolyn Shea

 

What happens when Komodos go head-to-head in combat?

Madeline A. Coccio, Pottstown, Pennsylvania

As Americans learned from last summer's Bronstein incident, in which newspaper editor Phil Bronstein (husband to actress Sharon Stone) nearly forfeited his toe to a Komodo dragon at the Los Angeles Zoo, these animals can be hazardous to one's health. The dragons, which can be 10 feet long and can weigh considerably more than 200 pounds, are not only the reigning giants of the lizard world but fierce carnivores as well (they may have inspired the legends of fire-breathing dragons). In the wild, Varanus komodoensis can take down a half-ton water buffalo, devour hunks of meat bigger than its head, and consume more than half its own weight in a single meal. Despite its lumbering appearance, this Indonesian reptile can sprint with alarming speed (up to 18 miles per hour). When it spies suitable nourishment, it lunges from its hiding place and ambushes its startled target. Once bitten, the victim, if it manages to escape, will later succumb to blood poisoning. Komodos' serrated teeth retain scraps from previous meals. This residuum supports dozens of bacterial strains--some of which are highly septic--making the predator's saliva a lethal weapon. Interestingly, a Komodo bite doesn't affect fellow Komodos in the same sickening way. Intraspecies battles, fought with tooth and claw during mating season, never result in infected combatants. It is thought that the animals possess antibodies that protect them from the same fate as their quarry--something Mr. Bronstein luckily avoided through the miracle of antibiotics.

Why is bleach harmful to the environment?

Leslie Gordon, Topanga, California

Bleach contains chlorine, element number 17 on that periodic chart that haunted you in science class. Discovered more than two centuries ago by an inveterate chemist named Carl Wilhelm Scheele--who christened it "dephlogisticated marine acid"--it is a highly reactive substance, meaning that it readily combines with other elements. When bound with sodium, chlorine forms sodium chloride, or table salt. In nature, chlorine is found largely in seawater and rarely exists on its own, but when it is isolated and freed from its chemical bonds, it becomes a toxic gas. During World War I, the poison was used as a weapon, thus spawning the ignominious age of chemical warfare. Today the world is awash in the stuff. Chlorine is used to produce polyvinyl chloride (PVC) plastics, herbicides, pesticides, cleansers, and pharmaceuticals; to bleach pulp and paper; and to disinfect water. All told, it is a component in about 15,000 products that have combined estimated annual sales of $71 billion. In spite of its prevalence, there is a movement to ban chlorine because it is suspected of causing a number of environmental problems, including ozone depletion. It is also thought to pose health threats to humans and wildlife, ranging from cancers to endocrine disruption. Chlorine is an ingredient in such notorious pollutants as DDT, PCBs, CFCs, Agent Orange, and dioxin. There's no question that household bleach, which is about 5 percent sodium hypochlorite, a mixture of chlorine and sodium hydroxide, is a dangerous product. But when used properly, bleach is effective for cleaning, laundering, and killing germs and algae. It does not contribute to the greenhouse effect or harm the ozone layer. If you are concerned about using chlorine, there are alternatives available, including borax and nonchlorine (oxygen) bleach. As a precaution, avoid purchasing as many chlorinated products as possible.

How do fish that live in closed bodies of water survive winter freezes?

Thomas Miller, Indianapolis, Indiana

Like all things governed by cyclical meteorological events, fish make the necessary adjustments to survive, even during the cruelest of months. In winter they quite literally chill. As poikilotherms (cold-blooded organisms), they maintain body temperatures equivalent to that of the water surrounding them. They also alter their lifestyles. Because ice floats on the top of all but the tiniest ponds and lakes, resident fish species often school in relatively warmer pockets of water near the bottom. Their metabolisms slacken, and the fish become less frisky. This slowdown is a boon for ice fishers, who camp out in droves to exploit the situation--unless the ice becomes so snow covered that it limits the amount of sunlight that can penetrate. In that case, photosynthesis stops, plants die and consume oxygen, and eventually the fish die off as well. At the North Pole and the South Pole, where the oceans are frozen year-round, fish have evolved proteins in their blood that act as antifreeze. So they don't end up like their brethren in the frozen-seafood section.


 

© 2002  NASI

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