Carbon dioxide is well known as a greenhouse gas involved in global warming. Less well known is that this gas can be deadly. This may surprise to some people, since carbon dioxide is a waste product that we regularly release into the air as we exhale. We are, of course, well adapted for this and seldom have problems under normal circumstances. There are some natural conditions, however, where carbon dioxide can be fatal.
Carbon dioxide molecules are made up of one carbon atom and two oxygen
atoms, and is heavier than normal air that's mostly made up of two-atom molecules.
Thus, carbon dioxide tends to accumulate in low spots unless air currents keep things
stirred up. In several places in the Southwest, travertine mounds have been built up by
carbon dioxide-containing spring water. Where water tables have dropped, the water
retreats, leaving a hollow mound. Carbon dioxide, seeping up into the cavity, forces
out the air, leaving an oxygen-less gas fatal to those who venture within. For more
than one explorer, that knowledge has come too late.
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.