James Elser, a limnologist and professor with Arizona State University’s School of Life Sciences, has been investigating the site since the mid-1990s and is one of a long line of ASU researchers to make the trek southward.
“Mostly, we’re studying how — in aquatic systems in this amazing place — how chemical elements shape the ecology and evolution of life here,” said Elser. “We started by researching systems like this with small stromatolites, studying the life forms that were present for billions of years on early Earth. We try to understand their ecology, how nutrients like phosphorus and nitrogen affect them, and then how food webs operate with them.
“Also, by using metagenomics techniques, we’re looking at how phosphorus and other chemical elements shape the ecology and the evolution of the bacteria,” he added.
Believed to be the remnants of an ancient sea, Cuatro Ciénegas is an important place to study, said Elser. “We think of it like a desert Galapagos. It’s this place with so many unique species. The vegetation and animals here in the valley have the highest level of endemic biodiversity in North America. We’ve known this for a while,” he added, “but we are also seeing incredible microbial diversity just from place to place, pond to pond. It’s like every pond is a little experiment in evolution.”
Minckley’s cave: A research legacy begins

The late W. L. Minckley (right) was the first ASU professor to begin research in Cuatro Ciénegas, Mexico. He discovered that the area is similar to the Galapagos Islands — filled with dozens of incredible species found nowhere else on Earth. He was the first of many generations of ASU researchers to study the area. Photo courtesy of ASU Archives
It all started with an ASU professor by the name of W. L. Minckley. He was, according to his peers, the best ichthyologist in the state of Arizona — ever. As a desert fish ecologist, Minckley spent his career studying fish species throughout the Southwest, including at the Cuatro Ciénegas basin.
A chance meeting with a colleague set the wheels in motion for Minckley to travel to the Chihuahuan desert and become the first of at least several generations of ASU researchers and students to study the area.
“This professor from the University of Kentucky who went to Mexico on a collecting trip, probably sometime in the ‘50s, came back with a box turtle that lives in the water,” said Elser. “And Minckley said, ‘No way. Box turtles don’t live in the water!’ He couldn’t believe it. He went to Mexico to verify this, and lo and behold! He found the endemic Cuatro Ciénegas box turtle, which is the world’s only box turtle that lives in the water.”
Minckley was hooked.
For several decades, he shared his fascination with Cuatro Ciénegas by bringing dozens of faculty and undergraduate and graduate students to Mexico, in hopes they would begin their own studies there. The groups would camp at the so- called “Minckley’s Cave” for days, collecting samples and studying the plant, invertebrate and fish species. Many of his students did begin their own research, some of which is ongoing.
After countless trips south, Minckley became well-known by the locals, and his research and that of other American and Mexican scientists showed the community and the Mexican government the importance of the basin and its biodiversity.
Their research became a catalyst for the Mexican government in 1994 to designate the habitat as a Natural Protected Area.
Before his passing in 2001, Minckley wrote some 175 research articles and penned three books. In recognition of his discoveries as a conservation biologist, five species, including a snail, a scorpion, a beetle, a fly and a cichlid fish, are assigned the name “minckleyi.” Several of these are from Cuatro Ciénegas. An aquarium in town and a small zoo are also named for him.
Near Poza Azul, one of the larger, deeply colored turquoise pools, stands a memorial honoring professor Minckley. His ashes were scattered nearby.
Cross-border collaborations
During Minckley’s 38 years of teaching at ASU, he forged critical international connections and collaborations — partnerships that continue even today.
Working abroad often comes with unique challenges — some of which cannot be easily overcome without support from local collaborators. In the case of Cuatro Ciénegas, Valeria Souza, a skilled microbiologist with Universidad Nacional Autónoma de Mexico, assists with obtaining sampling permits and access to several research sites, and also provides new research perspectives.
“It’s really important to have Mexican collaborators because this is their place,” said Elser. “They should be responsible for understanding and investigating Cuatro Ciénegas. And they are smart. They have great techniques and expertise. Valeria Souza, especially, is a force of nature. She creates a whirlwind of activity around her and makes a lot of things possible here.