Webbläsaren som du använder stöds inte av denna webbplats. Alla versioner av Internet Explorer stöds inte längre, av oss eller Microsoft (läs mer här: * https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Var god och använd en modern webbläsare för att ta del av denna webbplats, som t.ex. nyaste versioner av Edge, Chrome, Firefox eller Safari osv.

Reduced grazing rates in Daphnia pulex caused by contaminants: Implications for trophic cascades

In English

Författare

Summary, in English

Ecotoxicological endpoints based on behavioral traits (e.g., predator avoidance, feeding, and locomotion) may be more sensitive and give more insights into patterns of sublethal toxicity than survivorship tests. In this study, the density-dependent grazing rate of Daphnia pulex pre-exposed to p,p'-dichlorodiphenyldichloroethylene (DDE) (insecticide metabolite) and glyphosate (herbicide), via water or a vector, Scenedesmus spp., was assayed in laboratory experiments. The phytoplankton biomass was estimated from the chlorophyll content, and the pesticide uptake and turnover pattern in Daphnia and Scenedestnus were determined from parallel experiments with a radiolabeled source. Scenedestnus spp. relative net growth rate was inversely and linearly related to the density of the grazer. Daphnia pulex exhibited significant reductions in grazing rate: 30% for those pre-exposed to p,p'DDE via water and 40% for D. pulex pre-exposed to glyphosate via Scenedesmus spp. Through the process of trophic cascading, this impaired grazing allowed Scenedesmus spp. to grow at higher rates, 70 and 60%, respectively. The reduced grazing efficiencies were associated with the treatments that gave the highest body burden of p,p'-DDE (70 mug/g dry wt) and the lowest of glyphosate (13 mg/g dry wt). The pattern of results suggests a toxic effect of p,p'-DDE on D. pulex and a growth enhancement of Scenedesmus spp. in response to nitrogen and phosphorus in glyphosate excreted by D. pulex.

Publiceringsår

2004

Språk

Engelska

Sidor

2641-2648

Publikation/Tidskrift/Serie

Environmental Toxicology and Chemistry

Volym

23

Issue

11

Dokumenttyp

Artikel i tidskrift

Förlag

John Wiley & Sons Inc.

Ämne

  • Ecology

Status

Published

Forskningsgrupp

  • Aquatic Ecology

ISBN/ISSN/Övrigt

  • ISSN: 0730-7268