title: Interactive effects of xenobiotic, abiotic and biotic stressors on Daphnia pulex--results from a multiple stressor experiment with a fractional multifactorial design.
abstract: Pollutant effects on aquatic key species are confounded by multiple abiotic and biotic stressors. To better discriminate and understand the intrinsic and environmental correlates of changing aquatic ecosystems, we untangle in present study how the effects of a low-dosed fungicide on daphnids (via different exposure routes) becomes modified by increasing temperature and the presence of a predator. Using a fractional multifactorial test design, the individual growth, reproduction and population growth rate of Daphnia pulex were investigated under exposure to the fungicide pyrimethanil at an environmental relevant concentration--either directly (via the water phase), indirectly (via food), dually (via water and food) or for multiple generations (fungicide treated source population)--at three temperatures and in presence/absence of the predator kairomones of Chaoborus flavicans. Our results clearly illustrate that multiple stress factors can modify the response of an aquatic key species to pollutants. The environmentally relevant exposure of the contaminant via food or the medium is of same importance. Nevertheless, temperature and the presence of a predator are the dominant factors controlling the reproduction of D. pulex. We conclude that sublethal pyrimethanil pollution can disturb the zooplankton community at suboptimal temperature conditions, but the effects will become masked by low temperatures or if chaoborid larvae are present.
authors.affiliation: Goethe University Frankfurt am Main, Department Aquatic Ecotoxicology, Max-von-Laue-Strasse 13, D-60438 Frankfurt, Germany. c.scherer85@gmx.net
authors.forename: Christian
authors.initials: C
authors.lastname: Scherer
authors.forename: Anne
authors.initials: A
authors.lastname: Seeland
authors.forename: Jörg
authors.initials: J
authors.lastname: Oehlmann
authors.forename: Ruth
authors.initials: R
authors.lastname: Müller
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003621:Daphnia / Q000187:drug effects* / Q000254:growth & development; D004175:Diptera / Q000502:physiology; D005659:Fungicides, Industrial / Q000633:toxicity*; D005858:Germany; D007814:Larva / Q000502:physiology; D011157:Population Dynamics; D011235:Predatory Behavior / Q000502:physiology; D011743:Pyrimidines; D012098:Reproduction / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology*; D013696:Temperature
chemical_list: D005659:Fungicides, Industrial; D011743:Pyrimidines; C108337:pyrimethanil