INALI   02622
INSTITUTO NACIONAL DE LIMNOLOGIA
Unidad Ejecutora - UE
artículos
Título:
Exposure to sublethal chromium and endosulfan alter the diel vertical migration (DVM) in freshwater zooplanktonic crustaceans.
Autor/es:
GUTIERREZ, FLORENCIA; GAGNETÉN, ANA MARÍA; PAGGI, JUAN CESAR
Revista:
ECOTOXICOLOGY
Editorial:
SPRINGER
Referencias:
Año: 2011
ISSN:
0963-9292
Resumen:
Among zooplanktonic behaviors, diel migrations constitute one of the most effective predator-avoidance strategy and confer methabolic and demographic advantages. We aim to examine whether sublethal concentrations of two widespread pollutants (a pesticide with endosulfan and chromium as potassium dichromate) alter the depht selection, vertical migration and grouping of five freshwater species: Argyrodiaptomus falcifer, Notodiaptomus conifer, Pseudosida variabilis, Ceriodaphnia dubia and Daphnia magna. In a series of experimental assays, performed with 150 cm length transparent tubes, we analyzed the ascents and descents movements through periods of 24 h. Among controls, the copepods showed a tendency to remain closest to the surface, however  N. conifer registered a downward movement of 18.14 cm between 06:00 and 12:00. The cladoceran P.  variabilis occupied the deeper position (85 cm), C. dubia showed a tendency to hike to the surface at 06:00 (57.7 cm) descending to lower levels at 18:00. D. magna showed a constant movement of ascent between 00:00 and 18:00, making an average travel of 29.4 cm. When subjected to pollutants, these behaviors were altered. It is hipothesized that a reduction in swimming activity and disorientation would be the main cause of such alterations. The high sensitivity of this endpoint sugests it to be adecuate as a complement in future standard toxicity tests.