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Preliminary Limnologic Information on Waters of the Cuatro Cienegas Basin, Coahuila, Mexico

W. L. Minckley and Gerald A. Cole
The Southwestern Naturalist
Vol. 13, No. 4 (Dec. 31, 1968), pp. 421-431
DOI: 10.2307/3668909
Stable URL: http://www.jstor.org/stable/3668909
Page Count: 11
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Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preliminary Limnologic Information on Waters of the Cuatro Cienegas Basin, Coahuila, Mexico
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Abstract

Aquatic habitats in the Cuatro Ciénegas basin, central Coahuila, México, range from springs, through permanent streams and lakes, to ephemeral playas. There has been much disturbance through canalization, but most of the springs originally led via streams to closed saline lakes. A sequential change in ionic composition occurs with evaporation and concentration throughout such a series. Most waters are dominated by Ca++ and $\text{SO}_{4}{}^{--}$, and especially at their spring origins; with evaporation this changes to a dominance of Mg++ and $\text{SO}_{4}{}^{--}$, and a shift from a sulfato-carbonate water to a sulfato-chloride type. The Ca:Mg ratio is remarkably decreased in the more concentrated water. Total EDTA hardness ranged from 490 to 66,200 mg/liter, indicating the spectrum of chemical habitats represented. Most waters were similar at their spring origins, however, with hardness averaging near 1,200 mg/liter.

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