Kurzmitteilung
An artificial reservoir with the dominance of "Eubranchiopoda"
Villaclara, Gloria; Sládeček, Vladimír; Ján Bartek,
Archiv für Hydrobiologie Volume 119 Number 1 (1990), p. 115 - 116
5 Literaturangaben
veröffentlicht: Jul 20, 1990
DOI: 10.1127/archiv-hydrobiol/119/1990/115
ArtNo. ESP141011901008, Preis: 29.00 €
Abstract
The “Eubranchiopoda”, i. e. Anostraca, Notostraca and Conchostraca are commonly most characteristic inhabitants of temporary small water bodies like pools and ponds. It was thus a great surprise, when we realized, that the littoral plankton of a relatively big artificial reservoir is constantly inhabited by great numbers of two species of “Eubranchiopoda”. Pressa Encinillas is an artificial reservoir about 100 years old serving for irrigations in Central Mexico. It is situated near Jorobas town, at km 56 of the highway Mexico City—Quérétaro on the north-western edge of the México Megapolis. Its water level is fluctuating according to the dry and wet season between 0.3 and 2.5 m. Altitude is around 2400 m.a.s.l. The content of dissolved oxygen is relatively low, 1.5 up to 6.8mg • I-1. The water is turbid from fine mineral particles, pH fluctuates between 7.3 and 7.9 with an average of 7.6. Total alkalinity varies between 29.5 and 58.3 mval • 1-1, chlorides amounts up to 22mg • 1-1, conductivity from 4300 to 4600µS • cm-1, sulphates from 20 to 34 mg • I-1 and iron from 6 to 20 mg • I-1. On July 30, 1985 the plankton consisted of Ceriodaphnia, Daphnia, nauplii, cyclopoids and Cyclops. Many specimens of Colacium were attached at the copepods. The most interesting organisms were Streptocephalus mackini Moore (1966) (Anostraca) and Cyzicus mexicanus (Claus, 1860) (Conchostraca). Streptocephalus mackini was determined according to Moore (1966) and Belk (1975). It cannot be determined according to Dexter (1959) or Pennak (1953), where it is regarded S. texanus Packard (1871). According to Moore (1966) it occurs rarely in mixed populations together with S. texanus and S. similis. It is distributed on the high plateau areas of USA (Arizona, New Mexico, s. w. Texas) and Central Mexico (Chihuahua, Coahuila, Durango, Guanajuato, Hidalgo, Jalisco, Estado de México, Nuevo Leon, Puebla, Quérétaro, San Luis Potosi, Zacatecas). Our record is from the Estado de México. Cyzicus mexicanus was determined according to Mattox (1959). In the book of Pennak (1953) it is named Caenestheriella mexicana (Claus). It is widely distributed from Mexico through USA to southern Canada (Manitoba, Alberta). Both species are typical for the periodical pools or semi-permanent ponds as cattle tanks, roadside temporary ponds, periodical pools in the water filled depressions etc.
Schlagworte
short note