Scientists are working to identify this object that resembles a sphere and was found in the Vostok Station ice. © NASA | Marshall Space Center Scientists are working to identify this object, nicknamed porpoise, found in the Vostok Station ice. © NASA | Marshall Space Center Scientists used to think that life existed exclusively on the land and in the sunlit ocean shallows, with a huge void in the lightless regions of the deep sea. But a closer look just a few years ago shows that the "dead" sea floor is teeming with a diversity of life forms that rivals the diversity in other environments. Scientists equipped with new tools are also sampling and observing the midwaters and are finding a wealth of organisms never even dreamed of until now. Their most startling discovery was a vast, previously unrecognized biome - solid rock as much as two miles beneath the surface of the ocean - where bacteria thrive in countless millions. For example, Lake Vostok in Antarctica likely contains a microbial community that has been cut off from the rest of the biosphere for millions of years - under three kilometers of ice! Australia's world-renowned opal field, Coober Pedy, is home to another kind of treasure. Fossils are sometimes found there, preserved as chunks of dazzling opal. This semi-precious stone is exposed when tunneling machines crush large amounts of rock. When struck by the blades of the tunneler, an opal makes a distinct sound that alerts the operators to the presence of the gemstone. It's a crude, but effective technique. In 1987, opal miner Joe Veda stopped the machine when he heard that particular opal intonation. Veda had struck the skeleton of a small marine reptile called a pliosaur - the most complete vertebrate fossil preserved as opal. Despite the damage caused by the tunneler, enough of the skeleton was salvaged to show the tiny bones of a fish in its belly region - its last meal. © 2000 American Museum of Natural History