title: Population growth of Daphnia magna under multiple stress conditions: joint effects of temperature, food, and cadmium.
abstract: Aquatic organisms in the field often are exposed to combinations of stress factors of various origins. Little is known of the interaction between different types of stressors; hence, the predictability of their joint effects is low. Therefore, the present study analyzed the joint effects of temperature, food, and cadmium on the population growth rate of the water flea Daphnia magna. The results revealed that temperature, food, and cadmium, as well as their interactions, were important factors that influenced life-history parameters and, as a consequence, the population growth rate of D. magna. In general, population growth rate increased at high temperature and food level but decreased when cadmium was present. The positive effect of temperature on population growth rate was smallest at limiting food levels. Negative effects of cadmium on the growth rate were enhanced at elevated temperatures, whereas high food levels protected the daphnids from adverse effects of cadmium. To avoid over- or underestimation regarding the toxicity of substances to field populations, results of standard toxicity tests should be applied in a location-specific way.
authors.affiliation: Department of Aquatic Ecology, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands.
authors.forename: Evelyn H W
authors.initials: EH
authors.lastname: Heugens
authors.forename: Lonneke T B
authors.initials: LT
authors.lastname: Tokkie
authors.forename: Michiel H S
authors.initials: MH
authors.lastname: Kraak
authors.forename: A Jan
authors.initials: AJ
authors.lastname: Hendriks
authors.forename: Nico M
authors.initials: NM
authors.lastname: Van Straalen
authors.forename: Wim
authors.initials: W
authors.lastname: Admiraal
mesh_terms: D000818:Animals; D002104:Cadmium / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects* / Q000254:growth & development*; D005502:Food; D011157:Population Dynamics; D012098:Reproduction / Q000187:drug effects; D015996:Survival Rate; D013696:Temperature
chemical_list: D002104:Cadmium