The biosphere is usually thought of as plants and animals near Earth's surface, but Earth's habitable zone extends to depths of hundreds or thousands of meters. The organisms that live in this environment may collectively have a mass equivalent to that of all of Earth's surface dwellers and may provide keys to solving major environmental, agricultural, and industrial problems. Oregon State University's Suburface Biosphere Initiatve unites faculty and students from five different colleges who share interests in this underground world.