Word: nutrients
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...their competitors in many ways. Consider the erosion that accompanies deforestation and agriculture. No longer restrained by tree roots, tons of soil laden with nitrogen and phosphate washes into rivers and then sweeps into the sea, forming a muddy plume that may be hundreds of miles long. As this nutrient-rich water flows over a reef, it stimulates the growth of all kinds of algae--including the microscopic diatoms and dinoflagellates that nourish such reef animals as the crown-of-thorns starfish. In recent years hordes of these coral-devouring starfish have infested Australia's 1,200-mile-long Great...
...expel their zooxanthellae. Since it is the zooxanthellae that give coral colonies their rich coloration, their loss causes entire reefs to turn white. The stress that caused the recent bleachings, scientists say, was a seasonal spike in seawater temperatures. But other sources of stress, such as overfishing and nutrient overload, may have made the corals and their symbiotic friends unusually sensitive to heat...
...things, the tricks ensure that mutation will pile on mutation by shucking off, or silencing, genes that ordinarily monitor replicating DNA for chemical errors. The malignant cells quickly become resistant to the poisons physicians prescribe to kill them. They also acquire the disturbing ability to stimulate the formation of nutrient-bearing blood vessels, thus spurring their own growth. Even if malignant cells grow rather slowly, they grow inexorably, eventually forming a deadly mass that invades surrounding tissue and spreads, or metastasizes, to far-flung locations...
Like 500,000 other Americans each year, Lee was suffering a stroke. Something had cut off the flow of oxygen and nutrient-rich blood to a portion of her brain. Sometimes the culprit is a leaky artery. But in Phillips' case, as in 80% of strokes, the problem, revealed by a CAT scan, was a clot that was plugging up one of the blood vessels in her head. Unless the clot was dislodged, part of her brain would die, leaving her at least partly paralyzed...
...anything, have toxic effects on cells. Add to that the weakening over time of the immune system, which leads the body's fight against disease, and decline is inevitable. Biologists are now experimenting on rats and rhesus monkeys to see if restricting the intake of calories (while maintaining healthy nutrient levels) will slow the metabolic rate, producing a lower body temperature that in turn will decrease oxygen consumption. A lower rate of metabolism equals fewer radicals equals longer life...