Being part of the world of giants, we seldom appreciate the diversity of the more normal biosphere. Take a gram, a little over three hundredths of an ounce, of fertile Rio Grande Valley soil and look closely. Maybe a few critters crawling around, but nothing spectacular, certainly. Some recent work, though, suggests that spectacular hardly begins to describe the life in that clump of soil. Would you believe about a million different kinds of bacteria—bacteria entirely invisible to us until just a few hundred years ago, when the microscope began to reveal a new world.
Perhaps the nearest comparable discovery is the opening up of the
universe with the development of telescopes; a universe consisting of billions upon
billions of heavenly bodies where traditional knowledge had talked of thousands. Be
sure that your soil sample is from an unpolluted area, though. The same study that
revealed the astonishing diversity of microbial life suggests that although toxic metal
pollution doesn't decrease the number of individuals, it wipes out some 99.9% of
the bacterial species—a holocaust almost beyond belief.
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
Gans, J., M. Wolinsky, and J. Dunbar. 2005. Computational improvements reveal great bacterial diversity and high metal toxicity in soil. Science 309:1387-1390.