Abstract

Leaf litter is a major source of carbon and energy for stream food webs, while both leaf-decomposing microorganisms and macroinvertebrate leaf shredders can be affected by fungicides. Despite the potential for season-long fungicide exposure for these organisms, however, such chronic exposures have not yet been considered. Using an artificial stream facility, effects of a chronic (lasting up to 8 wk) exposure to a mixture of 5 fungicides (sum concentration 20 mu g/L) on leaf-associated microorganisms and the key leaf shredder Gammarus fossarum were therefore assessed. While bacterial density and microorganism-mediated leaf decomposition remained unaltered, fungicide exposure reduced fungal biomass (<= 71%) on leaves from day 28 onward. Gammarids responded to the combined stress from consumption of fungicide-affected leaves and waterborne exposure with a reduced abundance (<= 18%), which triggered reductions in final population biomass (18%) and in the number of precopula pairs (<= 22%) but could not fully explain the decreased leaf consumption (19%), lipid content (<= 43%; going along with an altered composition of fatty acids), and juvenile production (35%). In contrast, fine particulate organic matter production and stream respiration were unaffected. Our results imply that long-term exposure of leaf-associated fungi and shredders toward fungicides may result in detrimental implications in stream food webs and impairments of detrital material fluxes. These findings render it important to understand decomposer communities' long-term adaptational capabilities to ensure that functional integrity is safeguarded. (C) 2017 SETAC.

Keywords

Aquatic hyphomycetes; Chronic exposure; Gammarus fossarum; Leaf litter breakdown; Population development

Published in

Environmental Toxicology and Chemistry
2017, Volume: 36, number: 8, pages: 2178-2189

SLU Authors

• Feckler, Alexander

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Bundschuh, Mirco

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

SDG14 Conserve and sustainably use the oceans, seas and marine resources for sustainable development
SDG2 End hunger, achieve food security and improved nutrition and promote sustainable agriculture


UKÄ Subject classification

Environmental Sciences
Ecology


Publication identifier

DOI: https://doi.org/10.1002/etc.3756

Permanent link to this page (URI)

https://res.slu.se/id/publ/86299