@article{fdi:010073078,
  title = {{H}g-stable isotope variations in marine top predators of the {W}estern {A}rctic {O}cean},
  author = {{M}asbou, {J}. and {S}onke, {J}. {E}. and {A}mouroux, {D}. and {G}uillou, {G}. and {B}ecker, {P}. {R}. and {P}oint, {D}avid},
  editor = {},
  language = {{ENG}},
  abstract = {{R}ecent studies on mercury ({H}g)-stable isotopes in {A}laskan seabird eggs and ringed seal livers illustrated the control of sea ice cover on marine methyl-{H}g photochemistry. {H}ere, complementary marine mammal tissues have been analyzed to document variations in {H}g-, carbon ({C})-, and nitrogen ({N})-stable isotope compositions of {A}rctic marine food webs. {H}g-stable isotope ratios were measured in liver samples of 55 beluga whales ({D}elphinapterus leucas) and 15 polar bears ({U}rsus maritimus) collected since 1990. {L}arge variations in delta {H}g-202 (approximate to 2.1 parts per thousand) and {D}elta {H}g-199 (approximate to 1.7 parts per thousand) are observed between species and within species stocks covering the {G}ulf of {A}laska-{B}ering {S}ea-{A}rctic {O}cean regions. {P}olar bears, mainly feeding on ringed seal (delta {N}-15 shift of 4.2 parts per thousand), show identical liver {D}elta {H}g-199 of 0.5 parts per thousand, confirming the absence of metabolic mass-independent fractionation, and 0.33 +/- 0.11 parts per thousand enrichment in heavy {H}g isotopes. {B}eluga whale liver total {H}g concentrations increase with age, reflecting lifetime bioaccumulation, while {H}g speciation shifts to inorganic {H}g with age as a result of hepatic methyl-{H}g breakdown. {D}elta {H}g-200 variations in biota show a small, 0.1 parts per thousand decrease from {N}orth {P}acific {O}cean to {A}rctic {O}cean habitats, suggesting atmospheric {H}g deposition to be important in the {P}acific and terrestrial {H}g inputs to dominate in the {A}rctic {O}cean. {S}imilar to seabird eggs, a consistent south to north gradient in {D}elta {H}g-199 baseline is seen in mammal liver tissues, confirming sea ice cover as a control factor on marine {H}g photoreduction and {D}elta {H}g-199. {A}rctic {O}cean beluga whales have near zero {D}elta {H}g-199, indicating that terrestrial {H}g and in-situ-produced methyl-{H}g are not measurably photoreduced in the {A}rctic {O}cean before entering the marine food web.},
  keywords = {{A}rctic ; mercury ; isotopes ; {MIF} ; mammals ; {ARCTIQUE} {OCEAN}},
  booktitle = {},
  journal = {{ACS} {E}arth and {S}pace {C}hemistry},
  volume = {2},
  numero = {5},
  pages = {479--490},
  ISSN = {2472-3452},
  year = {2018},
  DOI = {10.1021/acsearthspacechem.8b00017},
  URL = {https://www.documentation.ird.fr/hor/fdi:010073078},
}