Effects of cadmium on a microbial food chain, Chlamydomonas reinhardii and Tetrahymena vorax.
A steady-state microbial food chain consisting of the green alga Chlamydomonas reinhardii and the ciliated protozoan Tetrahymena vorax was established in a two-stage, nitrogen-limited chemostat. The lowest concentration of cadmium which produced a toxic effect at the population level was between 7.5 and 10 micrograms l-1. The algal population acclimated to the presence of cadmium up to 40 micrograms l-1 added in increments over time, but demonstrated lowered cell numbers and reduced cell weights. Protozoan populations acclimated to 40 micrograms Cd l-1 added incrementally if the rate of dilution was lowered. Abrupt elevation of the cadmium concentration to 40 micrograms l-1 resulted in extreme fluctuations in the specific growth rates of both populations and the incipient loss of all cells from the system (washout).
Lawrence
S G
SG
Department of Fisheries and Oceans, Central and Arctic Region, Freshwater Institute Science Laboratory, Winnipeg, Manitoba, Canada.
Holoka
M H
MH
Hamilton
R D
RD
D000818:Animals; D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D002244:Carbon / Q000378:metabolism; D002696:Chlamydomonas / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D004784:Environmental Monitoring; D009584:Nitrogen / Q000378:metabolism; D013768:Tetrahymena / Q000187:drug effects* / Q000254:growth & development
D002104:Cadmium; D002244:Carbon; D009584:Nitrogen