title: Toxicity of two fungicides in Daphnia: is it always temperature-dependent?
abstract: The joint effect of increasing temperature and pollution on aquatic organisms is important to understand and predict, as a combination of stressors might be more noxious when compared to their individual effects. Our goal was to determine the sensitivity of a model organism (Daphnia spp.) to contaminants at increasing temperatures, allowing prior acclimation of the organisms to the different temperatures. Prior to exposure, two Daphnia genotypes (Daphnia longispina species complex) were acclimated to three temperatures (17, 20, and 23 °C). Afterwards, a crossed design was established using different exposure temperatures and a range of concentrations of two common fungicides (tebuconazole and copper). Daphnia life history parameters were analysed in each temperature × toxicant combination for 21 days. Temperature was the most influencing factor: Daphnia reproduced later and had lower fecundity at 17 °C than at 20 and 23 °C. Both copper and tebuconazole also significantly reduced the fecundity and survival of Daphnia at environmentally-relevant concentrations. Temperature-dependence was found for both toxicants, but the response pattern was endpoint- and genotype-specific. The combination of contaminant and high temperature often had severe effects on survival. However, unlike some literature on the subject, our results do not support the theory that increasing temperatures consistently foment increasing reproductive toxicity. The absence of a clear temperature-dependent toxicity pattern may result from the previous acclimation to the temperature regime. However, a proper framework is lacking to compare such studies and to avoid misleading conclusions for climate change scenarios.
authors.affiliation: Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.|CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Ana P
authors.initials: AP
authors.lastname: Cuco
authors.affiliation: CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal. njabrantes@ua.pt.|Department of Environment and Planning, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal. njabrantes@ua.pt.
authors.forename: Nelson
authors.identifier: http://orcid.org/0000-0003-0241-2896
authors.initials: N
authors.lastname: Abrantes
authors.affiliation: Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.|CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Gonçalves
authors.affiliation: Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Mueggelseedamm 301, 12587, Berlin, Germany.|Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität Berlin, Königi-Luise-Str. 1-5, 14195, Berlin, Germany.
authors.forename: Justyna
authors.initials: J
authors.lastname: Wolinska
authors.affiliation: CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.|CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Campus of Gualtar, 4710-057, Braga, Portugal.
authors.forename: Bruno B
authors.initials: BB
authors.lastname: Castro
mesh_terms: D000064:Acclimatization; D000818:Animals; D057231:Climate Change; D003621:Daphnia / Q000502:physiology*; D005659:Fungicides, Industrial / Q000633:toxicity*; D013696:Temperature; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D005659:Fungicides, Industrial; D014874:Water Pollutants, Chemical
keywords: Acclimation; Copper sulphate; Daphnia; Tebuconazole; Temperature rise