AB 17:153-166 (2012)  -  DOI: https://doi.org/10.3354/ab00472

Herbicide indirectly reduces physiological condition of a benthic grazer

M. Rybicki1,*, C. Winkelmann2, C. Hellmann2, P. Bartels3, D. Jungmann1

1Institute of Hydrobiology, Technische Universität Dresden, Zellescher Weg 40, 01217 Dresden, Germany
2Department of Biology, University Koblenz-Landau, Universitätsstrasse 1, 56070 Koblenz, Germany
3Helmholtz Centre for Environmental Research − UFZ, Department River Ecology, Brückstrasse 3a, 39114 Magdeburg, Germany

ABSTRACT: Freshwater ecosystems are polluted with various environmental chemicals. For example, pesticides enter the aquatic environment via spray drift or surface runoff from catchment areas used for industrialised agriculture. In the present study, we investigated the response of the grazer−aufwuchs interaction when exposed to the herbicide terbutryn in a microcosm experiment. Terbutryn induced a trophic cascade with negative effects on grazers by inhibiting growth of primary producers. We determined a no-observed-effect concentration (measured as particulate organic carbon, NOECPOC) of 0.21 µg l−1 for aufwuchs biomass and a lowest-observed-effect concentration (LOECPOC) of 2.01 µg l−1. Furthermore, a shift in the aufwuchs community was detected in all terbutryn treatments nearly 4 wk after exposure, and this shift persisted until the end of the experiment in the treatment with the highest terbutryn concentration. In addition, reduced energy stores (triglycerides, TG) of the grazer Rhithrogena semicolorata (Heptageniidae: Ephemeroptera) were found (NOECTG = 0.03 µg l−1, LOECTG = 0.21 µg l−1), which was interpreted as an indication of moderate starvation during the experiment. While starvation did not result in reduced larval growth as might have been expected, the observed reduction of TG content in larvae (24%) is consistent with results from a separate experiment in which starvation alone induced a 15% reduction of TG content as well as reduced emergence, reduced size at emergence, and reduced egg production.

KEY WORDS: Benthic grazing · Indirect effects · Herbicide · Mayfly · Rhithrogena semicolorata · Physiological condition · Fecundity

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Cite this article as: Rybicki M, Winkelmann C, Hellmann C, Bartels P, Jungmann D (2012) Herbicide indirectly reduces physiological condition of a benthic grazer. Aquat Biol 17:153-166. https://doi.org/10.3354/ab00472

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