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Exploring the effects of temperature and resource limitation on mercury bioaccumulation in Fundulus heteroclitus using dynamic energy budget modeling
Citation:
Clark, B., K. Buckman, D. Miller, A. Bertrand, I. Kirby, D. Champlin, C. Chen, AND D. Nacci. Exploring the effects of temperature and resource limitation on mercury bioaccumulation in Fundulus heteroclitus using dynamic energy budget modeling. Society of Toxicology 55th Annual Meeting and ToxExpo, New Orleans, LA, March 13 - 17, 2016.
Impact/Purpose:
To present to a peer audience new research that investigates the effects of temperature and resource availability on methylmercury bioavailability on estuarine fish using an energetic modeling approach.
Description:
Dynamic energy budget (DEB) theory provides a generalizable and broadly applicable framework to connect sublethal toxic effects on individuals to changes in population survival and growth. To explore this approach, we conducted growth and bioaccumulation studies that contribute to a DEB model, which allows joint acquisition and interpretation of chemical exposure and stressor effect information that readily translates into demographic rate changes. Ultimately, we will develop a test framework that connects molecular mechanistic information to population level fitness. As a test case, we are studying the effects of temperature and resource availability on mercury (Hg) accumulation in the estuarine fish Fundulus heteroclitus. Methylmercury (MeHg), a potent neurotoxin and global contaminant, accumulates in marine food webs raising concerns for human exposure. Warming temperatures, occurring with global climate change, may increase MeHg production and bioaccumulation through increased food consumption and MeHg accumulation. However, higher temperatures may also lead to increased growth and reduced MeHg accumulation through somatic growth dilution. In the current study, groups of juvenile mummichog were fed tuna naturally contaminated with Hg at one of two feeding rates (3.3% or 10% dry body weight/day) while held at either 15 or 27 °C for 28 days. Growth was low in most treatments, except in fish fed 10% body weight held at 27 °C (40% weight and 12% length increase). From preliminary chemical analyses, MeHg bioaccumulation was similar across feeding conditions but increased with temperature (~17-fold increase in MeHg concentration at 27 °C compared to a ~7-fold increase at 15 °C, regardless of feeding rate). The use of these data in a DEB model may aid in understanding why temperature is the dominant driver of MeHg accumulation at this scale, regardless of feeding or growth rate. Overall, this work contributes to the ongoing development of an ecological modeling framework in a fish species with an extensive toxicological and genomic background.