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Article
Biogeochemical Analysis of Ancient Pacific Cod Bone Suggests Hg Bioaccumulation was Linked to Paleo Sea Level Rise and Climate Change
Frontiers in Environmental Science
  • Maribeth S. Murray, University of Calgary - Canada
  • C. Peter McRoy, University of Alaska - Fairbanks
  • L. K. Duffy, University of Alaska - Fairbanks
  • Amy Hirons, Nova Southeastern University
  • J. M. Schaaf, United States National Park Service
  • Robert P. Trocine, Florida Institute of Technology - Melbourne
  • John Trefry, Florida Institute of Technology - Melbourne
Document Type
Article
Publication Date
2-17-2015
Keywords
  • Mercury,
  • Stable isotopes,
  • Bering Sea,
  • Coastal flooding,
  • Holocene,
  • Climate change,
  • Sea level
Peer Reviewed
1
Abstract

Deglaciation at the end of the Pleistocene initiated major changes in ocean circulation and distribution. Within a brief geological time, large areas of land were inundated by sea-level rise and today global sea level is 120 m above its minimum stand during the last glacial maximum. This was the era of modern sea shelf formation; climate change caused coastal plain flooding and created broad continental shelves with innumerable consequences to marine and terrestrial ecosystems and human populations. In Alaska, the Bering Sea nearly doubled in size and stretches of coastline to the south were flooded, with regional variability in the timing and extent of submergence. Here we suggest how past climate change and coastal flooding are linked to mercury bioaccumulation that could have had profound impacts on past human populations and that, under conditions of continued climate warming, may have future impacts. Biogeochemical analysis of total mercury (tHg) and δ13C/δ15N ratios in the bone collagen of archeologically recovered Pacific Cod (Gadus macrocephalus) bone shows high levels of tHg during early/mid-Holocene. This pattern cannot be linked to anthropogenic activity or to food web trophic changes, but may result from natural phenomena such as increases in productivity, carbon supply and coastal flooding driven by glacial melting and sea-level rise. The coastal flooding could have led to increased methylation of Hg in newly submerged terrestrial land and vegetation. Methylmercury is bioaccumulated through aquatic food webs with attendant consequences for the health of fish and their consumers, including people. This is the first study of tHg levels in a marine species from the Gulf of Alaska to provide a time series spanning nearly the entire Holocene and we propose that past coastal flooding resulting from climate change had the potential to input significant quantities of Hg into marine food webs and subsequently to human consumers.

Comments

© 2015 Murray, McRoy, Duffy, Hirons, Schaaf, Trocine and Trefry. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CCBY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

Additional Comments
NSF award #: 0525275
DOI
10.3389/fenvs.2015.00008
Citation Information
Maribeth S. Murray, C. Peter McRoy, L. K. Duffy, Amy Hirons, et al.. "Biogeochemical Analysis of Ancient Pacific Cod Bone Suggests Hg Bioaccumulation was Linked to Paleo Sea Level Rise and Climate Change" Frontiers in Environmental Science Vol. 3 (2015) p. 1 - 8 ISSN: 2296-665X
Available at: http://works.bepress.com/amy-hirons/15/