Mercury offloaded in Northern elephant seal hair affects coastal seawater surrounding rookery

Jennifer M. Cossaboon, Priya M. Ganguli, A. Russell Flegal, Francois M. M. Morel

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Methylmercury (MeHg) is a potent neurotoxin that is biomagnified approximately 1-10 million-fold in aquatic carnivores such as the Northern elephant seal (Mirounga angustirostris), whose excreta and molted pelage, in turn, constitute a source of environmental MeHg contamination at the base of marine food chains. The potential for this top-down contamination is greatest in coastal areas with productive marine ecosystems that provide ideal habitats for large marine mammal colonies that can number in the thousands. This recycling of MeHg was evidenced by comparing total mercury (HgT) and MeHg concentrations in seawater, and HgT in molted pelage of M. angustirostris, at the Año Nuevo State Reserve pinniped rookery with concentrations at neighboring coastal sites in Central California. Seawater MeHg concentrations around the rookery (average = 2.5 pM) were markedly higher than those at the comparison coastal sites (average = 0.30 pM), and were as high as 9.5 pM during the M. angustirostris molting season. As a consequence, excreta and molts from this marine mammal colony, and presumably other marine predator populations, constitute a major source of MeHg at the base of the local marine food chain.

Original languageEnglish (US)
Pages (from-to)12058-12062
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number39
StatePublished - Sep 29 2015

All Science Journal Classification (ASJC) codes

  • General


  • Biogeochemistry
  • Biomagnification
  • Environmental toxicology
  • Marine mammals
  • Mercury


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