Yellowstone's more than 10,000 geysers, hot springs, mud pots and fumaroles awe and delight 3 million park visitors each year. They are also drawing the interest of biotechnology companies and academic researchers like Ward, a professor at Montana State University, and Ramsing, a postdoctoral student. Long thought to be too hot and harsh to sustain any form of life, the park's geothermal attractions contain an astonishing variety of micro- organisms, whose ability to survive both high temperatures and extremes of acidity and alkalinity--from battery acid to household ammonia--makes them potentially valuable