Description
Metal toxicity was investigated in two pH tolerant species of cichlids, Tapajos cichlids (Geophagussp.) and Oscars (Astronotus ocellatus) from the Rio Negro, an ion-poor acidic blackwater water. We measured rates of Na+uptake and loss during exposure to dissolved copper, and silver. Exposure of Tapajos cichlids to 1000 µg/L Cu2+ inhibited Na+ ?influx by 45.5% and stimulated Na+ efflux by 23.9%. Exposure to 1 µM Ag+completely inhibited Na+ ?influx of Tapajos while increasing efflux threefold, and 200 mg/L Ni2+ increased efflux by 43.8%. These metals and others will be looked at on Astronotus ocellatus. These results indicate cichlids show high resistance to copper and nickel, but Ag+ completely inhibits Na+influx and causes leaky gills.
Is Metal Toxicity Effect on Ion Regulation Similar to pH Toxicity in Amazonian Fish?
Metal toxicity was investigated in two pH tolerant species of cichlids, Tapajos cichlids (Geophagussp.) and Oscars (Astronotus ocellatus) from the Rio Negro, an ion-poor acidic blackwater water. We measured rates of Na+uptake and loss during exposure to dissolved copper, and silver. Exposure of Tapajos cichlids to 1000 µg/L Cu2+ inhibited Na+ ?influx by 45.5% and stimulated Na+ efflux by 23.9%. Exposure to 1 µM Ag+completely inhibited Na+ ?influx of Tapajos while increasing efflux threefold, and 200 mg/L Ni2+ increased efflux by 43.8%. These metals and others will be looked at on Astronotus ocellatus. These results indicate cichlids show high resistance to copper and nickel, but Ag+ completely inhibits Na+influx and causes leaky gills.