@article {232, title = {Holocene changes in Proboscia diatom productivity in shelf waters of the north-western Antarctic Peninsula}, journal = {Antarctic Science}, volume = {22}, year = {2010}, note = {id: 789; 559YJ Times Cited:0 Cited References Count:51Y}, pages = {3-10}, abstract = {Diatoms are important primary producers in present day Antarctic waters but their relative significance in the past is less clear. In this Study We used long-chain diols to reconstruct Proboscia diatom productivity in shelf waters of the western Antarctic Peninsula over the last 8500 yr. Biomarker lipid analysis revealed the presence of a suite of long-chain diols in the sediments, mainly comprising the C-28 and C-30 1,14-diol isomers derived from Proboscia diatoms and C-28 and C-30 1,13-diols derived from other unknown algae. The relative importance of Proboscia diatoms was assessed using the relative abundances of 1, 14-diols versus 1, 13-diols, which showed that Proboscia diatoms were relatively more abundant during the Late Holocene, suggesting that stronger upwelling of circumpolar waters Occurred at that time. The variations in the diol index strongly correlate with melt events in the Siple Dome ice core, Suggesting that the climatic processes responsible for changes in mean summer temperature, open marine influence and atmospheric cyclonic activity recorded at Siple Dome, also controlled the productivity of Proboscia diatoms on the western Antarctic Peninsula region.}, issn = {0954-1020}, doi = {10.1017/S095410200999037x}, author = {Willmott, V. and Rampen, S. W. and Domack, E. and Canals, M. and Damste, J. S. S. and Schouten, S.} } @article {254, title = {Antarctic sediment chronology by programmed-temperature pyrolysis: Methodology and data treatment}, journal = {Geochemistry Geophysics Geosystems}, volume = {9}, year = {2008}, note = {id: 1847; 284ON Times Cited:5 Cited References Count:27Y}, abstract = {We report a detailed programmed-temperature pyrolysis/ combustion methodology for radiocarbon (C-14) dating of Antarctic sub-ice shelf sediments. The method targets the autochthonous organic component in sediments that contain a distribution of acid-insoluble organic components from several sources of different ages. The approach has improved sediment chronology in organic-rich sediments proximal to Antarctic ice shelves by yielding maximum age constraints significantly younger than bulk radiocarbon dates from the same sediment horizons. The method proves adequate in determining isotope ratios of the pre-aged carbon end-member; however, the isotopic compositions of the low-temperature measurements indicate that no samples completely avoided mixing with some proportion of pre-aged organic material. Dating the unresolved but desired young end-member must rely on indirect methods, but a simple mixing model cannot be developed without knowledge of the sedimentation rate or comparable constraints. A mathematical approach allowing for multiple mixing components yields a maximum likelihood age, a first-order approximation of the relative proportion of the autochthonous component, and the temperature at which allochthonous carbon begins to volatilize and mix with the autochthonous component. It is likely that our estimation of the cutoff temperature will be improved with knowledge of the pyrolysis kinetics of the major components. Chronology is improved relative to bulk acid-insoluble organic material ages from nine temperature interval dates down to two, but incorporation of inherently more pre-aged carbon in the first division becomes more apparent with fewer and larger temperature intervals.}, issn = {1525-2027}, doi = {10.1029/2007gc001816}, author = {Rosenheim, B. E. and Day, M. B. and Domack, E. and Schrum, H. and Benthien, A. and Hayes, J. M.} } @article {1924, title = {Refining the radiocarbon dating of Antarctic marine sediments via stepped combustion}, journal = {Eps Trans AGU}, volume = {87}, year = {2006}, note = {id: 702}, month = {2006}, author = {Schrum, H. and Hayes, J. and Domack, E.} }