Effects of interactions between algal densities and cadmium concentrations on Ceriodaphnia dubia fecundity and survival.
The influence of different densities of the algae Pseudokirchneriella subcapitata on the chronic toxicity of cadmium to Ceriodaphnia dubia was investigated. The importance of algal cells as a source of metal to zooplankton was studied by exposing P. subcapitata cells to free cadmium ions and supplying the algae as food to C. dubia. The results of a bifactorial analysis (metal versus food levels) showed that metal toxicity to zooplankton was dependent on food level. Significant toxic effects on the fecundity and survival of C. dubia were observed at low metal concentrations with high algal density. Algae contaminated with Cd(2+) were less toxic to cladoceran than was the Cd(2+) in solution. Green algae retained cadmium and released low metal concentration in the test medium. We concluded that algal cells are an important route of exposure to metal and a factor that has an appreciable influence on the expression of metal toxicity to daphnids.
Rodgher
Suzelei
S
São Carlos Engineering School, Water Resources and Applied Ecology Center, University of São Paulo, Avenida Trabalhador São Carlense, 400, C.P 292, Cep 13.560-970 São Carlos, SP, Brazil. surodgher@uol.com.br
Luiz Gaeta Espíndola
Evaldo
E
D000818:Animals; D002104:Cadmium / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D000460:Chlorophyta / Q000254:growth & development* / Q000378:metabolism; D003621:Daphnia / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005298:Fertility / Q000187:drug effects; D020387:Food Chain; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*; D015048:Zooplankton / Q000187:drug effects
D014874:Water Pollutants, Chemical; D002104:Cadmium