title: Exposure pathway-dependent effects of the fungicide epoxiconazole on a decomposer-detritivore system.
abstract: Shredders play a central role in the breakdown of leaf material in aquatic systems. These organisms and the ecological function they provide may, however, be affected by chemical stressors either as a consequence of direct waterborne exposure or through alterations in food-quality (indirect pathway). To unravel the biological relevance of these effect pathways, we applied a 2×2-factorial test design. Leaf material was microbially colonized for 10days in absence or presence of the fungicide epoxiconazole (15μg/L) and subsequently fed to the shredder Asellus aquaticus under exposure to epoxiconazole (15μg/L) or in fungicide-free medium over a 28-day period (n=40). Both effect pathways caused alterations in asselids' food processing, physiological fitness, and growth, although not always statistically significantly: assimilation either increased or remained at a similar level relative to the control suggesting compensatory behavior of A. aquaticus to cope with the enhanced energy demand for detoxification processes and decreased nutritional quality of the food. The latter was driven by lowered microbial biomasses and the altered composition of fatty acids associated with the leaf material. Even with increased assimilation, direct and indirect effects caused decreases in the growth and lipid (fatty acid) content of A. aquaticus with relative effect sizes between 10 and 40%. Moreover, the concentrations of two essential polyunsaturated fatty acids (i.e., arachidonic acid and eicosapentaenoic acid) were non-significantly reduced (up to ~15%) in asselids. This effect was, however, independent of the exposure pathway. Although waterborne effects were generally stronger than the diet-related effects, results suggest impaired functioning of A. aquaticus via both effect pathways.
authors.affiliation: Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 75007 Uppsala, Sweden. Electronic address: alexander.feckler@slu.se.
authors.forename: Alexander
authors.initials: A
authors.lastname: Feckler
authors.affiliation: Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 75007 Uppsala, Sweden.
authors.forename: Willem
authors.initials: W
authors.lastname: Goedkoop
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, 76829 Landau, Germany.
authors.forename: Jochen P
authors.initials: JP
authors.lastname: Zubrod
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, 76829 Landau, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Schulz
authors.affiliation: Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 75007 Uppsala, Sweden; Institute for Environmental Sciences, University of Koblenz-Landau, 76829 Landau, Germany.
authors.forename: Mirco
authors.initials: M
authors.lastname: Bundschuh
mesh_terms: D029661:Alnus / Q000187:drug effects* / Q000382:microbiology; D000818:Animals; D004852:Epoxy Compounds / Q000378:metabolism / Q000633:toxicity*; D020387:Food Chain; D005659:Fungicides, Industrial / Q000378:metabolism / Q000633:toxicity*; D033321:Isopoda / Q000187:drug effects* / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000382:microbiology; D014230:Triazoles / Q000378:metabolism / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D004852:Epoxy Compounds; D005659:Fungicides, Industrial; D014230:Triazoles; D014874:Water Pollutants, Chemical; C109476:epoxiconazole
keywords: Asellus aquaticus; Biofilm; Fatty acid composition; Food quality; Leaf litter breakdown; Shredder