Cuatro Ciénegas Basin
Snorkeling in the Chihuahuan Desert

Cuatro Ciénegas is both a town in a basin in the Chihuahuan Desert, and the name of the basin itself. The name, Cuatro Ciénegas, means four marshes, and comes from the fact that the 500 square mile area has many springs, lakes, and pools of water fed by a natural underground system of water channels. It is difficult to picture snorkeling in the middle of the Chihuahuan Desert, but in Cuatro Ciénegas that is exactly what happens. And it is not only the water that is unusual. There are also gypsum fields in Cuatro Ciénegas, similar to those found in White Sands NM, and these are the only ones in Mexico.

Cuatro Ciénegas has more than 75 endemic species, because the animals that survived here have been isolated from others for so long that they developed unusual adaptations. There is a Coahuilan box turtle which spends most of its life underwater, a very unusual life for box turtles who usually live on land. There are schools of pupfish, each only about an inch long, that live in pools of very salty hot water. There are cichlids, fish with powerful teeth in their throats for crushing snail shells on which they feed. And there are grass shrimp that live in pools rich with algae. Out of 16 species of fish found in the basin, 8 are found nowhere else in the world. And in addition to these species, there are many others, like wild horses and burros, that live in this water rich oasis.

The lakes and pools in Cuatro Ciénegas vary from the largest which is 250 feet wide and 25 feet deep, to pools the size of small aquariums. Most of the water has a high mineral content because it bubbles up from deep below the surface. Some of it is hot and some cold, but most of it is crystal clear and easy to see into. There are other areas in Cuatro Ciénegas where water runoff from precipitation has collected in pools and then evaporated. This has formed wet areas called salt marshes, in which many fish, snakes and turtles live. Adding to this naturally occurring water is the presence of canals that have been dug by the human inhabitants. These canals also are home to many fish. There is a bit of a scientific mystery as to exactly how and why so much water flows to the surface in this one place. However, regardless of why, this has produced a desert wetland in Cuatro Ciénegas, which is rare on the earth.

References

Grall, G. (1995, October). Cuatro Ciénegas: Mexico's desert aquarium. In National Geographic, 188 (4), 84-97.

Savage, R. (1996, August 15). Cuatro Ciénegas: An archipelago of emerald waters [On-line]. Available: Internet: http://www.tnc.org/texas/cuacengl.html