HYPOTHESISThis work is based on the study of the existenceof a vertical migration and a differentdensities of zooplankton at different depths inthe Guadalquivir river.

PROCEDURETo test this hypothesis, the abundances of organismsat two different depths of 0-2.5 m and 2.5-5 m werestudied. To collect samples a plankton net with amouth of 0'6 m in diameter and a light mesh of 250microns was used, collecting two samples from eachdepth.

COMPARATIVE STUDY OF THE FAUNA PRESENT IN TWO SUBSYSTEMS OF A WATERCOURSE

ESTUDIO COMPARATIVO DE LA FAUNA PRESENTE EN DOS SUBSISTEMAS DE AGUA

AUTORS: MANUEL ANTEQUERA LOZANO, ALEJANDRO RIZO BORREGO, LUCIA GILABERT GRANERO, ALBA LOBATO FERNÁNDEZ, LUÍS PEREZ JIMENEZ.

PROFESSOR: CÉSAR MEGINA MARTINEZTeacher: ROSA MARIA GUERRA MORILLA, ALINA CHMIELEWSKI

Centres: I.E.S ÍTACA, I.E.S JUAN CIUDAD DUARTE, I.E.S CHAVES NOGALES

MATERIALS

From the samples with higher abundances oforganisms, preparations of specimens were made tobe examined by a microscope; some of these sampleswere stained to study anatomical details such as theantennas and muscle bands. Upon completion of thecounting of the subsamples a table was made tocompare the density of organisms at each depth.

MATERIALS

CONCLUSIONS

Identified zooplankters were mainly copepods, with a low proportion of maturefemales; cladocerans were also found, although with a low abundance.Results show that the distribution of the zooplankton is not homogeneous, whatsupport the existence of daily vertical migrations in these organisms.These results were discussed taking into account factors such as predators, light,temperature, food, etc.

ACKNOWLEDMENTS

We want to thank the Faculty of Biology of theUniversity of Seville for lending us their facilities.

We also want to thank our teachers AlinaChmielewski and Rosa María Guerra Molina, and theprofessor César Megina Martinez who has supervisedthe realization of this work