High-precision isotopic analysis sheds new light on mercury metabolism in long-finned pilot whales (Globicephala melas)

Eduardo Bolea-Fernandez, Ana Rua-Ibarz, Eva M. Krupp, Jörg Feldmann, Frank Vanhaecke (Corresponding Author)

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Abstract

Whales accumulate mercury (Hg), but do not seem to show immediate evidence of toxic effects. Analysis of different tissues (liver, kidney, muscle) and biofluids (blood, milk) from a pod of stranded long-finned pilot whales (Globicephala melas) showed accumulation of Hg as a function of age, with a significant decrease in the MeHg fraction. Isotopic analysis revealed remarkable differences between juvenile and adult whales. During the first period of life, Hg in the liver became isotopically lighter (δ202Hg decreased) with a strongly decreasing methylmercury (MeHg) fraction. We suggest this is due to preferential demethylation of MeHg with the lighter Hg isotopes and transport of MeHg to less sensitive organs, such as the muscles. Also changes in diet, with high MeHg intake in utero and during lactation, followed by increasing consumption of solid food contribute to this behavior. Interestingly, this trend in δ202Hg is reversed for livers of adult whales (increasing δ202Hg value), accompanied by a progressive decrease of δ202Hg in muscle at older ages. These total Hg (THg) isotopic trends suggest changes in the Hg metabolism of the long-finned pilot whales, development of (a) detoxification mechanism(s) (e.g., though the formation of HgSe particles), and Hg redistribution across the different organs.
Original languageEnglish
Article number7262
JournalScientific Reports
Volume9
DOIs
Publication statusPublished - 13 May 2019

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isotopic analysis
whale
metabolism
muscle
lactation
methylmercury
detoxification
milk
blood
mercury
isotope
diet
food

Keywords

  • element cycles
  • marine mammals
  • mass spectrometry
  • stable isotope analysis
  • HEAVY-METALS
  • MARINE MAMMALS
  • TRACE-ELEMENTS
  • FOOD WEBS
  • METHYLMERCURY
  • ABIOTIC METHYLATION
  • INORGANIC MERCURY
  • PACIFIC HARBOR SEAL
  • STRIPED DOLPHIN
  • PHOCA-VITULINA-RICHARDII

ASJC Scopus subject areas

  • General

Cite this

High-precision isotopic analysis sheds new light on mercury metabolism in long-finned pilot whales (Globicephala melas). / Bolea-Fernandez, Eduardo; Rua-Ibarz, Ana; Krupp, Eva M.; Feldmann, Jörg; Vanhaecke, Frank (Corresponding Author).

In: Scientific Reports, Vol. 9, 7262, 13.05.2019.

Research output: Contribution to journalArticle

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abstract = "Whales accumulate mercury (Hg), but do not seem to show immediate evidence of toxic effects. Analysis of different tissues (liver, kidney, muscle) and biofluids (blood, milk) from a pod of stranded long-finned pilot whales (Globicephala melas) showed accumulation of Hg as a function of age, with a significant decrease in the MeHg fraction. Isotopic analysis revealed remarkable differences between juvenile and adult whales. During the first period of life, Hg in the liver became isotopically lighter (δ202Hg decreased) with a strongly decreasing methylmercury (MeHg) fraction. We suggest this is due to preferential demethylation of MeHg with the lighter Hg isotopes and transport of MeHg to less sensitive organs, such as the muscles. Also changes in diet, with high MeHg intake in utero and during lactation, followed by increasing consumption of solid food contribute to this behavior. Interestingly, this trend in δ202Hg is reversed for livers of adult whales (increasing δ202Hg value), accompanied by a progressive decrease of δ202Hg in muscle at older ages. These total Hg (THg) isotopic trends suggest changes in the Hg metabolism of the long-finned pilot whales, development of (a) detoxification mechanism(s) (e.g., though the formation of HgSe particles), and Hg redistribution across the different organs.",
keywords = "element cycles, marine mammals, mass spectrometry, stable isotope analysis, HEAVY-METALS, MARINE MAMMALS, TRACE-ELEMENTS, FOOD WEBS, METHYLMERCURY, ABIOTIC METHYLATION, INORGANIC MERCURY, PACIFIC HARBOR SEAL, STRIPED DOLPHIN, PHOCA-VITULINA-RICHARDII",
author = "Eduardo Bolea-Fernandez and Ana Rua-Ibarz and Krupp, {Eva M.} and J{\"o}rg Feldmann and Frank Vanhaecke",
note = "Eduardo Bolea-Fernandez acknowledges BOF-UGent for his postdoctoral grant. We acknowledge Arnout Laureys for his support, Jonas Kunigkeit and Magali Perez for isolation of HgSe particles, and Dr. Andrew Brownlow for given access to the Pilot Whale samples.",
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AU - Bolea-Fernandez, Eduardo

AU - Rua-Ibarz, Ana

AU - Krupp, Eva M.

AU - Feldmann, Jörg

AU - Vanhaecke, Frank

N1 - Eduardo Bolea-Fernandez acknowledges BOF-UGent for his postdoctoral grant. We acknowledge Arnout Laureys for his support, Jonas Kunigkeit and Magali Perez for isolation of HgSe particles, and Dr. Andrew Brownlow for given access to the Pilot Whale samples.

PY - 2019/5/13

Y1 - 2019/5/13

N2 - Whales accumulate mercury (Hg), but do not seem to show immediate evidence of toxic effects. Analysis of different tissues (liver, kidney, muscle) and biofluids (blood, milk) from a pod of stranded long-finned pilot whales (Globicephala melas) showed accumulation of Hg as a function of age, with a significant decrease in the MeHg fraction. Isotopic analysis revealed remarkable differences between juvenile and adult whales. During the first period of life, Hg in the liver became isotopically lighter (δ202Hg decreased) with a strongly decreasing methylmercury (MeHg) fraction. We suggest this is due to preferential demethylation of MeHg with the lighter Hg isotopes and transport of MeHg to less sensitive organs, such as the muscles. Also changes in diet, with high MeHg intake in utero and during lactation, followed by increasing consumption of solid food contribute to this behavior. Interestingly, this trend in δ202Hg is reversed for livers of adult whales (increasing δ202Hg value), accompanied by a progressive decrease of δ202Hg in muscle at older ages. These total Hg (THg) isotopic trends suggest changes in the Hg metabolism of the long-finned pilot whales, development of (a) detoxification mechanism(s) (e.g., though the formation of HgSe particles), and Hg redistribution across the different organs.

AB - Whales accumulate mercury (Hg), but do not seem to show immediate evidence of toxic effects. Analysis of different tissues (liver, kidney, muscle) and biofluids (blood, milk) from a pod of stranded long-finned pilot whales (Globicephala melas) showed accumulation of Hg as a function of age, with a significant decrease in the MeHg fraction. Isotopic analysis revealed remarkable differences between juvenile and adult whales. During the first period of life, Hg in the liver became isotopically lighter (δ202Hg decreased) with a strongly decreasing methylmercury (MeHg) fraction. We suggest this is due to preferential demethylation of MeHg with the lighter Hg isotopes and transport of MeHg to less sensitive organs, such as the muscles. Also changes in diet, with high MeHg intake in utero and during lactation, followed by increasing consumption of solid food contribute to this behavior. Interestingly, this trend in δ202Hg is reversed for livers of adult whales (increasing δ202Hg value), accompanied by a progressive decrease of δ202Hg in muscle at older ages. These total Hg (THg) isotopic trends suggest changes in the Hg metabolism of the long-finned pilot whales, development of (a) detoxification mechanism(s) (e.g., though the formation of HgSe particles), and Hg redistribution across the different organs.

KW - element cycles

KW - marine mammals

KW - mass spectrometry

KW - stable isotope analysis

KW - HEAVY-METALS

KW - MARINE MAMMALS

KW - TRACE-ELEMENTS

KW - FOOD WEBS

KW - METHYLMERCURY

KW - ABIOTIC METHYLATION

KW - INORGANIC MERCURY

KW - PACIFIC HARBOR SEAL

KW - STRIPED DOLPHIN

KW - PHOCA-VITULINA-RICHARDII

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DO - 10.1038/s41598-019-43825-z

M3 - Article

VL - 9

JO - Scientific Reports

JF - Scientific Reports

SN - 2045-2322

M1 - 7262

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