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  • 1
    ISSN: 1573-5117
    Schlagwort(e): Mysidacea ; life-tables ; populations ; toxicology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This study examines the application of population statistics to laboratory-derived toxicological data for the purpose of developing a predictive model that assesses the population consequences of pollutant and environmentally-induced stress. Life tables are used to calculate age-specific survivorship, fecundity, intrinsic rate of population increase (r), and reproductive value (Va), for populations ofMysidopsis bahia chronically exposed, in separate tests, to mercury and nickel. The population statistics, r, and Va, and pollutant dose are defined quantitatively, and the critical value (r = 0) for the intrinsic rate of population increase is compared with traditional toxicological measures of acute and chronic toxicity. The effects of an environmental variable, predation, significantly reduce the critical value (r = 0) for the intrinsic rate of growth and demonstrate the interactions of multiple stressors. The use of the population statistic, r, is recommended for estimating the ecological significance of toxicological data and for facilitating the assessment of interactions between pollutant-stressed populations and dynamic environmental pressures.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1573-5117
    Schlagwort(e): Mysidacea ; cadmium ; toxicology ; opossum shrimp ; Mysidopsis bahia ; Mysidopsis bigelowi
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two species of mysid shrimp, the sub-tropicalMysidopsis bahia and the northern temperateMysidopsis bigelowi, were exposed simultaneously to cadmium (as CdCl2) in a continuous-flow bioassay system to determine the effect on survival and reproductive success. Temperature and salinity were maintained at 21 ± 1°C and 30‰,respectively. The 96-h LC50 was 110 µg ℓ−1 for both species. The 23-day life cycle LC50 forM. bahia was 19.5 µg ℓ−1 and forM. bigelowi the 27-day LC-50 was 14.8 µg ℓ−1. At 10 µg ℓ−1 a series of morphological aberrations were observed in both species at the onset of sexual maturity. Carapace malformations apparently prevented molting after the release of the initial brood and resulted in death of brooding females. As a result, although the initial reproductive rate at this concentration was successful, successive broods could not be produced. For both species in this study the no observed effect concentration was 5.1 µg ℓ−1; the effect concentration was 10.0 µg ℓ−1. Mechanisms were postulated in this study to explain the effect of cadmium on the molting process and on calcification and enzymatic reactions of osmosis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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