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PT13 Aquatic Ecotoxicology I
(PT199) Chronic population-level effects of aqueous copper and cadmium on Palaemonetes pugio.
Manyin, T1, Rowe, C1, 1 Chesapeake Biological Laboratory, Solomons, MD, USA
ABSTRACT- Newly hatched Palaemonetes pugio (grass shrimp) larvae have been exposed to low concentrations of aqueous copper or cadmium, through metamorphosis to the juvenile stage and into early adulthood, for 112 days in an ongoing laboratory experiment to measure population-level effects. At copper free ion concentrations of 8.7 and 26 g Cu2+/L, duration of larval period increased. At 26 g Cu2+/L, a small percentage (0.5%) of juveniles exhibited developmental defects upon metamorphosis, which were not observed in control individuals. No significant effects have been observed on survival at either copper concentration, but thus far, adults at both copper concentrations have been unable to produce viable eggs. Cadmium free ion concentrations of 1.4 and 2.3 g Cd2+/L have not had a significant effect on larval or early juvenile survival, but mortality in both cadmium treatments has increased slightly at the end of the juvenile stage and at the beginning of the adult stage. Cadmium has had no significant effect on fecundity of young adults. Measurement of survival and fecundity will continue until individuals reach their maximum reproductive capacity, and effects on the second generation will also be observed. Stage-based matrix models of population growth under conditions of copper and cadmium exposure will be presented, using the data generated from this life table response experiment. The increase in larval duration exhibited in copper treatments may have important ramifications for survival, due to high mortality in the larval stage, as compared to the juvenile and adult stages. It remains to be seen whether the lack of reproductive success under copper exposure will continue into later adulthood; if so, there may be profound effects on the sustainability of P. pugio populations exposed to low concentrations of copper, despite the absence of copper-induced mortality.
Key words: stage-based matrix model, life table response experiment, chronic effects, heavy metals
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