A comparison of mercury biomagnification through lacustrine food webs supporting Brook Trout (Salvelinus fontinalis) and other salmonid fishes

Methyl mercury (MeHg) bioaccumulation in lower-trophic-level organisms and its subsequent biomagnification through food webs differs in magnitude among lakes and results in intraspecific variability of MeHg in top predator fishes. Understanding these differences is critical given the reproductive an...

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Bibliographic Details
Published in:Frontiers in Environmental Science
Main Authors: Monica LD Finley, Karen A Kidd, R Allen Curry, Gretchen L Lescord, Meredith G Clayden, Nelson J O'Driscoll
Format: Article in Journal/Newspaper
Language:English
Published: Frontiers Media S.A. 2016
Subjects:
Mercury
Stable isotopes
food webs
brook trout
trophic magnification slope
envir
archeo
Arctic
Canada
Online Access:https://doi.org/10.3389/fenvs.2016.00023
https://doaj.org/article/a975e75aaf4e4009850b857a3a1b72db
Description
Summary:Methyl mercury (MeHg) bioaccumulation in lower-trophic-level organisms and its subsequent biomagnification through food webs differs in magnitude among lakes and results in intraspecific variability of MeHg in top predator fishes. Understanding these differences is critical given the reproductive and neurotoxic effects of MeHg on fishes and their predators, including humans. In this study we characterized the food webs of five lakes in New Brunswick, Canada, supporting Brook Trout (Salvelinus fontinalis) using measures of relative trophic position (δ15N) and carbon sources (δ13C), determined the concentrations of MeHg in invertebrates and total Hg (THg) in fishes, and quantified MeHg biomagnification from primary to tertiary consumers. Methyl Hg and THg concentrations were highest in biota from lakes with lower pH. The trophic magnification slopes (TMS; log Hg versus δ15N) varied significantly among lakes (0.12-0.20; ANCOVA, p=0.031). When combined with data from other salmonid lakes in temperate and Arctic Canada (n=36), among-system variability in TMS was best, but weakly, positively predicted by aqueous total phosphorous (p = 0.028, R2adj = 0.109). These results suggest that lake productivity directly or indirectly influences the biomagnification of MeHg through diverse food webs supporting salmonids.

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