Dazzling ecological significance of 'Precambrian' oasis in the Chihuahuan Desert, endemic turtles, industrial agriculture, and the degradation of Cuatro Cienegas
(Originally posted elsewhere on 23 May 2022.)
At the oasis of Cuatro Cienegas, in the Chihuahuan Desert of Coahuila south of the Big Bend of the Rio Grande, more than 90% of the oasis pools and wetlands have already dried and disappeared due to water extraction for private land development, alfalfa agriculture, and cattle rangeland.
At least 38 animal species live nowhere else except at Cuatro Cienegas.
The oasis is home to not one, not two, but three endemic species of turtles that live nowhere else on the planet. Including: the planet’s only aquatic species of box turtle (Terrapene coahuila), described as one of the planet’s “most endangered” turtles; an endemic species of softshell turtle (Apalone spinifera atra); and an endemic slider (Trachemys taylori).
What else can be found at the oasis?
An endemic alligator lizard, many endemic desert fish, snails, strange cactus, white sand dunes of gypsum, and 2,200-year-old petroglyphs.
And, famously, the oasis is the place on the planet with the highest known diversity of the Archaea order of lifeofrms, creatures that are about 3.5 billion years old, older than bacteria. The oasis is also home to one of the planet’s only terrestrial populations of soft-bodied ancient stromatolite bacterial mats (which are usually marine creatures/structures, living at deep-sea hydrothermal vents, but instead also live here in the desert, isolated from the ocean for millions of years). Stromatolites were key species in Precambrian seas and their adaptations to the scarce phosphorous of the oasis spring water are apparently similar to the very earliest Archaea from the planet’s oceans several billion years ago.
The nearly-extinct endemic aquatic box turtle (Terrapene coahuila):
The endemic softshell (Apalone spinifera atra):
The endemic slider (Trachemys taylori):
And some images from an article about Cuatro Cienegas, written by Rodrigo Perez Ortega and published by AAAS Science Magazine on 30 June 2020 (”Improbable Oasis: Pools in the Mexican desert are a window into Earth’s earliest life.”).
The stromatolites:
