Methylmercury dietary pathways and bioaccumulation in Arctic benthic invertebrates of the Beaufort Sea

This study investigated methylmercury (MeHg) concentrations in Arctic benthic invertebrates from two shelf sites in the Canadian Beaufort Sea. Carbon, nitrogen, and sulfur stable isotopes and fatty acids were measured to examine diet influences on MeHg concentrations in 476 individuals from 53 taxa...

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Bibliographic Details
Published in:Arctic Science
Main Authors: Christine McClelland, John Chételat, Kathleen Conlan, Alec Aitken, Mark R. Forbes, Andrew Majewski
Format: Article in Journal/Newspaper
Language:English
French
Published: Canadian Science Publishing 2024
Subjects:
Arctic Ocean
Beaufort Sea
benthic invertebrate
mercury
stable isotope
fatty acid
Environmental sciences
GE1-350
Environmental engineering
TA170-171
Arctic
Cape Bathurst
Mackenzie River
Mackenzie river
Online Access:https://doi.org/10.1139/as-2023-0021
https://doaj.org/article/b907a2e6cefa4b4fade8160c48dc9eb2
Description
Summary:This study investigated methylmercury (MeHg) concentrations in Arctic benthic invertebrates from two shelf sites in the Canadian Beaufort Sea. Carbon, nitrogen, and sulfur stable isotopes and fatty acids were measured to examine diet influences on MeHg concentrations in 476 individuals from 53 taxa of benthic invertebrates representing three different feeding guilds. Taxonomic identifications were based on DNA-barcoding and traditional taxonomy. MeHg concentrations ranged from 3 to 421 ng/g dry weight and increased over three trophic levels (δ15N range = 4.4–14.2‰). Organic matter sources had small but significant influences on MeHg bioaccumulation in the benthic food web. Carbon stable isotope ratios (δ13C, range = −25.5 to −19.8‰) were positively correlated with MeHg concentrations, suggesting greater reliance on benthic carbon contributed to higher concentrations. Sulfur stable isotopes were unrelated to MeHg concentrations. Fatty acids suggested feeding on diatoms versus dinoflagellates, and reliance on benthic resources influenced MeHg concentrations. Higher MeHg concentrations were observed at the site closer to the Mackenzie River mouth than the Cape Bathurst site. This study generated the most taxonomically rich dataset of MeHg concentrations in invertebrates from the Arctic marine benthos to date and provides a basis for future research on food web MeHg dynamics in the Canadian Beaufort Sea.

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