Habitat-specific foraging and sex determine mercury concentrations in sympatric benthic and limnetic ecotypes of threespine stickleback

James J. Willacker, Frank A. von Hippel, Kerri L. Ackerly, Todd M. O'Hara

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Mercury (Hg) is a widespread environmental contaminant known for the neurotoxicity of its methylated forms, especially monomethylmercury, which bioaccumulates and biomagnifies in aquatic food webs. Mercury bioaccumulation and biomagnification rates are known to vary among species utilizing different food webs (benthic vs limnetic) within and between systems. The authors assessed whether carbon and nitrogen stable isotope values and total Hg (THg) concentrations differed between sympatric benthic and limnetic ecotypes and sexes of threespine stickleback fish (Gasterosteus aculeatus) from Benka Lake, Alaska, USA. The mean THg concentration in the limnetic ecotype was significantly higher (difference between benthic and limnetic means equals 26mg/kg dry wt or 16.1%) than that of the benthic ecotype. Trophic position and benthic carbon percentage utilized were both important determinants of THg concentration; however, the 2 variables were of approximately equal importance in females, whereas trophic position clearly explained more of the variance than benthic carbon percentage in males. Additionally, strong sex effects (mean difference between females and males equals 45mg/kg dry wt or 29.4%) were observed in both ecotypes, with female fish having lower THg concentrations than males. These results indicate that trophic ecology and sex are both important determinants of Hg contamination even within a single species and lake and likely play a role in governing Hg concentrations in higher trophic levels. Environ Toxicol Chem 2013;32:1623-1630.

Original languageEnglish (US)
Pages (from-to)1623-1630
Number of pages8
JournalEnvironmental Toxicology and Chemistry
Volume32
Issue number7
DOIs
StatePublished - Jul 2013
Externally publishedYes

Keywords

  • Benthic carbon
  • Bioaccumulation
  • Biomagnification
  • Gasterosteus aculeatus
  • Trophic position

ASJC Scopus subject areas

  • Environmental Chemistry
  • Health, Toxicology and Mutagenesis

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