| Autor: |
Heddle C; Biological Sciences, Simon Fraser University, Biological Sciences, Burnaby, BC, V5A 1S6, Canada., Elliott JE; Biological Sciences, Simon Fraser University, Biological Sciences, Burnaby, BC, V5A 1S6, Canada. john.elliott@canada.ca.; Environment and Climate Change Canada, Ecotoxicology and Wildlife Health Directorate, Delta, BC, V4K 3N2, Canada. john.elliott@canada.ca., Brown TM; Biological Sciences, Simon Fraser University, Biological Sciences, Burnaby, BC, V5A 1S6, Canada., Eng ML; Biological Sciences, Simon Fraser University, Biological Sciences, Burnaby, BC, V5A 1S6, Canada.; Toxicology Centre, University of Saskatchewan, Saskatoon, SK, S7N 5B3, Canada., Perkins M; Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, QC, H9X 3V9, Canada.; Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA., Basu N; Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, QC, H9X 3V9, Canada., Williams TD; Biological Sciences, Simon Fraser University, Biological Sciences, Burnaby, BC, V5A 1S6, Canada. |
| Abstrakt: |
Methylmercury (MeHg) is a global environmental contaminant that bioaccumulates and has multiple toxic modes of action. Aquatic species have traditionally been the focus of wildlife toxicological research on mercury, but terrestrial organisms, including passerine birds, can be exposed to similarly elevated levels of MeHg. In this study we exposed a model passerine, the zebra finch (Taeniopygia guttata), to MeHg in ovo, as chicks only, or with a combined 'in ovo + chick' treatment. We isolated exposure to specific developmental stages through the use of egg injections (3.2 µg Hg/g egg) and controlled oral dosing of chicks (0.24 µg Hg/g bw/day from day 1 to day 30). In ovo exposure to MeHg reduced hatching success, but there was no effect of MeHg on chick growth. We found that in ovo only or chick only exposure did not have long-term effects, but there was some evidence for longer-term effects of combined 'in ovo + chick' exposure on post-fledging survival and potentially sex-biased survival which resulted in very few 'in ovo + chick' exposed females surviving to breed. These females also had lower overall breeding productivity that was mainly due to lower hatching success of their offspring, not lower chick-rearing success. We found no effect of treatment on clutch size or latency to laying among females that did lay eggs. Our study suggests that combined embryonic and nestling MeHg exposure has compounding latent effects on productivity, likely through a mechanism that influences the ability of females to lay fertile eggs that hatch. |
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