Preliminary Limnologic Information on Waters of the Cuatro Cienegas Basin, Coahuila, Mexico
1968; Southwestern Association of Naturalists; Volume: 13; Issue: 4 Linguagem: Inglês
10.2307/3668909
ISSN1943-6262
AutoresW. L. Minckley, Gerald A. Cole,
Tópico(s)Water Resource Management and Quality
ResumoAquatic habitats in the Cuatro Cienegas basin, central Coahuila, Mexico, 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 S04--, and especially at their spring origins; with evaporation this changes to a dominance of Mg+ + and SO4--, 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. Studies of limnology in northern M'xico are scarce (Cole, 1963, 1968), and especially in the Bolsones Region of the Mesa del Norte. Many remnants of large Pluvial lakes became extinct in this part of MIxico during the last 100 years, before having been studied. Laguna de Mayr~n, for example, known to occupy part of the basin of a major lake that was partially drained by structural uplift in Pleistocene (Arellano, 1951), held considerable water in 1926 (Goldman, 1951), but was dry when visited by Deevey in 1941 (Deevey, 1957) and when seen by Minckley in 1964 (unpublished). Death of this lake may be partially attributed to irrigation diversions in its drainage (Tamayo and West, 1964), but drying trends and lake recessions certainly occurred in the late 1800 prior to man's impact on the water resources of the region (see Meek, 1904). The numerous large lakes of northern M6xico such as lagos de Guzman, Patos, Parras, Santa Maria, and so on (Meek, loc. cit.), probably have recent histories similar to that of Mayrin. The Cuatro Cienegas basin in central Coahuila, Mexico, has within an area of a few hundred km2 a range of aquatic habitats unexcelled in any other desert bols6n known to us. The basin is situated in the
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