title: Radionuclides in ornithogenic sediments as evidence for recent warming in the Ross Sea region, Antarctica.
abstract: Radionuclides including (210)Pb, (226)Ra and (137)Cs were analyzed in eight ornithogenic sediment profiles from McMurdo Sound, Ross Sea region, East Antarctica. Equilibration between (210)Pb and (226)Ra were reached in all eight profiles, enabling the determination of chronology within the past two centuries through the Constant Rate of Supply (CRS) model. Calculated fluxes of both (210)Pb and (137)Cs varied drastically among four of the profiles (MB4, MB6, CC and CL2), probably due to differences in their sedimentary environments. In addition, we found the flux data exhibiting a clear decreasing gradient in accordance with their average deposition rate, which was in turn related to the specific location of the profiles. We believe this phenomenon may correspond to global warming of the last century, since warming-induced surface runoff would bring more inflow water and detritus to the coring sites, thus enhancing the difference among the profiles. To verify this hypothesis, the deposition rate against age of the sediments was calculated based on their determined chronology, which showed ascending trends in all four profiles. The significant increase in deposition rates over the last century is probably attributable to recent warming, implying a potential utilization of radionuclides as environmental indicators in this region.
authors.affiliation: Institute of Polar Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China; Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province, Hefei, Anhui 230031, China.
authors.forename: Yaguang
authors.initials: Y
authors.lastname: Nie
authors.affiliation: School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui 230009, China.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Xu
authors.affiliation: Institute of Polar Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China. Electronic address: ycx@ustc.edu.cn.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Biology and Marine Biology, University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28403, USA.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Emslie
keywords: (210)Pb and (137)Cs flux; (210)Pb dating; Climate warming; Ornithogenic sediments; Radionuclides; Ross Sea region