1. Tissue content of thiol-containing amino acids predicts methylmercury in aquatic invertebrates
- Author
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Karen A. Kidd, Nelson J. O'Driscoll, Robert F. Bertolo, and Jennifer C. Thera
- Subjects
Aquatic Organisms ,Environmental Engineering ,010504 meteorology & atmospheric sciences ,Cysteic acid ,010501 environmental sciences ,01 natural sciences ,Zooplankton ,chemistry.chemical_compound ,Animals ,Environmental Chemistry ,Sulfhydryl Compounds ,14. Life underwater ,Amino Acids ,Waste Management and Disposal ,Methylmercury ,0105 earth and related environmental sciences ,Trophic level ,chemistry.chemical_classification ,Methionine ,Aquatic animal ,Methylmercury Compounds ,Invertebrates ,Pollution ,Amino acid ,Nova Scotia ,chemistry ,13. Climate action ,Environmental chemistry ,Water Pollutants, Chemical ,Environmental Monitoring ,Cysteine - Abstract
Aquatic invertebrates vary in methylmercury (MeHg) levels among systems which has been attributed, in part, to environmental conditions, but may also be linked to differences in their biochemical composition. As MeHg is known to bind to thiol-containing amino acids such as cysteine in proteins of fish, our objective was to determine if these amino acids explain MeHg variability among aquatic invertebrate taxa. Benthic macroinvertebrates from diverse functional feeding groups and bulk zooplankton were collected from six acidic lakes in Kejimkujik National Park, Nova Scotia, Canada, and analyzed for MeHg, cysteine (as cysteic acid), methionine (as methionine sulfone), and nitrogen (relative trophic level, δ 15 N) and carbon (carbon source, δ 13 C) isotopes. MeHg was significantly and positively related to cysteine or methionine in zooplankton, caddisfly and stonefly tissues (R 2 from 0.24 to 0.57). In addition, methionine or cysteine in combination with δ 15 N and/or δ 13 C were better predictors of MeHg levels in stoneflies, mayflies, caddisflies and zooplankton among these lakes (R 2 adj = 0.25–0.91). Overall, these novel findings suggest that the variability in MeHg of aquatic invertebrates can be explained, in part, by their tissue levels of thiol-containing amino acids.
- Published
- 2019