We're all pretty much familiar with the concept of a food chain, where plants are eaten by herbivores who are eaten by predators who, in turn, may be eaten by yet other predators. This usually seems to work out pretty good for the top predators, who have few if any enemies. Of course, those further down the food chain may have distinctly more sour viewpoints about the whole process.
There are times, though, when being top dog, so to speak, isn't so
swift. The trouble is that poisons tend to accumulate in the body as you go up the
chain, ending at the top in disaster, as we saw, for example, with DDT. A different
sort of poison accumulation is now beginning to show up. Even deleterious substances
originating in our Chihuahuan Desert may ultimately end up affecting life far to the
north. We now recognize that airborne contaminants may travel far and ultimately become
trapped in glacial ice. As the climate warms, these glaciers are rapidly dumping the
poisons accumulated over scores of years into ponds and streams.
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.