Heugens Evelyn H W, Tokkie Lonneke T B, Kraak Michiel H S, Hendriks A Jan, Van Straalen Nico M, Admiraal Wim
Department of Aquatic Ecology, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands.
Environ Toxicol Chem. 2006 May;25(5):1399-407. doi: 10.1897/05-294r.1.
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.
野外的水生生物常常会受到各种来源的应激因素的综合影响。对于不同类型应激源之间的相互作用，我们了解得很少；因此，它们共同作用的可预测性很低。所以，本研究分析了温度、食物和镉对水蚤大型溞种群增长率的联合影响。结果表明，温度、食物、镉以及它们之间的相互作用，都是影响生活史参数的重要因素，进而影响了大型溞的种群增长率。一般来说，在高温和食物充足的水平下，种群增长率会增加，但当存在镉时则会下降。在食物有限的水平下，温度对种群增长率的积极影响最小。镉对生长率的负面影响在温度升高时会增强，而高食物水平则能保护水蚤免受镉的不利影响。为了避免高估或低估物质对野外种群的毒性，标准毒性测试的结果应以因地制宜的方式应用。
