A mixture of environmental organic contaminants in lake sediments affects hatching from Daphnia resting eggs.
Despite the relevance of resting eggs for ecology and evolution of many aquatic organisms and their exposure to contaminants accumulating in sediments, ecotoxicological studies using resting eggs are vastly underrepresented. The authors established a method to perform exposure assays with resting eggs produced by the Daphnia longispina species complex, key species in large lake ecosystems. A mixture of organic contaminants previously detected in sediments of Lake Greifensee was selected to test the potential effect of organic contaminants present in sediments on the hatching process. Resting eggs were exposed to a mix of 10 chemicals, which included corrosion inhibitors, biocides, pesticides, and personal care products, for a period of 15 d. Using an automated counting software, the authors found a significant increase in hatching success in the exposed resting eggs compared with controls. Such an effect has not yet been reported from ecotoxicological assays with resting eggs. Possible mechanistic explanations as well as the potential implications on the ecology and evolution of aquatic species that rely on a resting egg banks are discussed. Observed increased mortality and developmental abnormalities for hatchlings in the exposure treatments can be explained by toxic contaminant concentrations. The results of the present study highlight the need for additional studies assessing the effects of organic contaminants on resting egg banks and aquatic ecosystems.
Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland.
Markus
M
Möst
Aurea C
AC
Chiaia-Hernandez
Martin P
MP
Frey
Juliane
J
Hollender
Piet
P
Spaak
D000818:Animals; D003621:Daphnia / Q000187:drug effects / Q000502:physiology*; D004781:Environmental Exposure; D019015:Geologic Sediments / Q000737:chemistry*; D060106:Lakes / Q000737:chemistry*; D016014:Linear Models; D009930:Organic Chemicals / Q000633:toxicity*; D010063:Ovum / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D009930:Organic Chemicals; D014874:Water Pollutants, Chemical
Daphnia; Mixture toxicology; Organic contaminants; Resting egg bank; Sediment toxicity