Mercury Exposure is Associated with Negative Effects on Turtle Reproduction

Abstract

Mercury (Hg), a ubiquitous and highly toxic bioaccumulative contaminant, can maternally transfer and elicit deleterious effects on adult reproduction and offspring phenotype in fish, amphibians, and birds. However, the effects of Hg on reproduction remain largely unstudied in reptiles. We evaluated the consequences of maternally transferred Hg on a long-lived aquatic omnivore, the common snapping turtle (Chelydra serpentina). We collected eggs and tissues from gravid female turtles along a broad Hg contamination gradient in a river in central Virginia. We incubated eggs in the laboratory, quantified embryonic mortality, infertility, and hatching success of each clutch, and assessed all hatchlings and dead embryos for gross morphological malformations. As predicted, Hg concentrations in eggs were strongly and positively correlated with Hg levels in female tissues. We found that Hg in eggs was negatively correlated with hatching success, and this effect was driven by both increased egg infertility and embryonic mortality. In comparison to previous effect-based studies on other amniotes, our findings suggest that C. serpentina may be more resilient to Hg exposure and perhaps better suited for long-term monitoring of bioavailability of Hg than as indicators of adverse effects.

High levels of maternally transferred mercury disrupt magnetic responses of snapping turtle hatchlings (Chelydra serpentina)

“…The three eggs from each clutch were lyophilized and homogenized before being pooled as a composite sample. Samples were analyzed for total Hg at the College of William and Mary, Williamsburg, VA (see Hopkins et al (2013)) for additional information regarding Hg analysis). We tested multiple measures of performance of single hatchlings from 12 reference and 12 contaminated clutches.…”

Malformación del miembro torácico derecho en Trachemys dorbigni

“…In turtles, it was found that herbicides can affect organs and embryos, as well as mercury contamination (Hopkins et al, 2013, Zapata et al, 2014 and polychlorinated biphenyls (Matsumoto et al, 2014). Due to the strong anthropic pressure observed in the region, it is possible that Trachemys dorbigni has been mutating, and this can affect the permanence of this species in its natural environment.…”

Like mother, like offspring: maternal and offspring wound healing correlate in snakes

“…Future studies that examine species known to experience deleterious effects in response to Hg exposure [e.g. Bufo americanus, Thryothorus ludovicianus, Tachycineta bicolor and Chelydra serpentina (Bergeron et al, 2011;Hallinger et al, 2011;Jackson et al, 2011;Hopkins et al, 2013)] and that include larger sample sizes are needed to clarify the effects of Hg on wound healing and other aspects of immune function in wildlife.…”