|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 Limnological Research Center, University of Minnesota, Minneapolis, Minnesota 55455
2 Department of Geology, Hamilton College, Clinton, New York 13323
3 U.S. Geological Survey, Reston, Virginia 22092
4 Institute for Rock Magnetism, University of Minnesota, Minneapolis, Minnesota 55455
5 Department of Geology, Colgate University, Hamilton, New York 13346
6 Department of Geology, Middlebury College, Middlebury, Vermont 05753
Compared to the rest of the world's oceans, high-resolution late Holocene paleoclimatic data from the Southern Ocean are still rare. We present a multiproxy record from a sediment core retrieved from a deep basin on the western side of the Antarctic Peninsula that reveals a dramatic perspective on paleoclimatic changes over the past 3700 yr. Analyses completed include measurement of magnetic susceptibility and granulometry, bed thickness, particle size, percent organic carbon, bulk density, and microscopic evaluation of diatom and benthic foraminiferal assemblages and abundances. Downcore variability of these parameters demonstrates the significance of both short-term cycles, which recur approximately every 200 yr, and longer term events (
2500 yr cycles) that are most likely related to global climatic fluctuations.
In the upper 600 cm of the core, lower values of magnetic susceptibility (MS) are correlated with lower bulk density, the presence of thinly laminated units, specific diatom assemblages, and generally higher total organic carbon content. Below 600 cm, magnetic susceptibility is uniformly low, though variability in other parameters continues. The magnetic susceptibility signal is controlled primarily by dilution of ferromagnetic phases with biosiliceous material. This signal may be enhanced further by dissolution of magnetite in the magnetic susceptibility lows (high total organic carbon). The role of variable primary productivity and its relationship to paleoclimate is assessed through the diatom data. In particular, magnetic susceptibility lows are characterized by higher than normal abundances of Chaetoceros resting spores. Corethron criophilum and/or Rhizosolenia spp. also are found, as is a higher ratio of the most common species of Fragilariopsis versus species of Thalassiosira. These assemblages are indicative of periods of high primary productivity driven by the presence of a meltwater stabilized water column. The 200 yr cyclicity noted in other paleoclimatic records around the world suggests a global forcing mechanism, possibly solar variability. In addition to the cyclic changes in productivity, overall elevated productivity is noted below 600 cm, or prior to ca. 2500 yr B.P. This increased productivity may represent the tail end of a Holocene climatic optimum, which is widely recognized in other parts of the world, but as yet is poorly documented in Antarctica.
This article has been cited by other articles:
|
|
 |
|
  M. Montes-Hugo, S. C. Doney, H. W. Ducklow, W. Fraser, D. Martinson, S. E. Stammerjohn, and O. Schofield Recent Changes in Phytoplankton Communities Associated with Rapid Regional Climate Change Along the Western Antarctic Peninsula Science, March 13, 2009; 323(5920): 1470 - 1473. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M.J. Bentley, D.A. Hodgson, J.A. Smith, C.O Cofaigh, E.W. Domack, R.D. Larter, S.J. Roberts, S. Brachfeld, A. Leventer, C. Hjort, et al. Mechanisms of Holocene palaeoenvironmental change in the Antarctic Peninsula region The Holocene, February 1, 2009; 19(1): 51 - 69. [Abstract] [PDF]
|
|
|
|
 |
|
 A. Clarke, N. M Johnston, E. J Murphy, and A. D Rogers Introduction. Antarctic ecology from genes to ecosystems: the impact of climate change and the importance of scale Phil Trans R Soc B, January 29, 2007; 362(1477): 5 - 9. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Clarke, E. J Murphy, M. P Meredith, J. C King, L. S Peck, D. K.A Barnes, and R. C Smith Climate change and the marine ecosystem of the western Antarctic Peninsula Phil Trans R Soc B, January 29, 2007; 362(1477): 149 - 166. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. G. Lucchi and M. Rebesco Glacial contourites on the Antarctic Peninsula margin: insight for palaeoenvironmental and palaeoclimatic conditions Geological Society, London, Special Publications, January 1, 2007; 276(1): 111 - 127. [Abstract] [PDF]
|
|
|
|
|
|
A. J. Nederbragt, R. B. Dunbar, A. T. Osborn, A. Palmer, J. W. Thurow, and T. Wagner Sediment colour analysis from digital images and correlation with sediment composition Geological Society, London, Special Publications, January 1, 2006; 267(1): 113 - 128. [Abstract] [PDF]
|
|
|
|
 |
|
 S. H.H. Nielsen, N. Koc, and X. Crosta Holocene climate in the Atlantic sector of the Southern Ocean: Controlled by insolation or oceanic circulation? Geology, April 1, 2004; 32(4): 317 - 320. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Brachfeld, E. Domack, C. Kissel, C. Laj, A. Leventer, S. Ishman, R. Gilbert, A. Camerlenghi, and L. B. Eglinton Holocene history of the Larsen-A Ice Shelf constrained by geomagnetic paleointensity dating Geology, September 1, 2003; 31(9): 749 - 752. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Schimmelmann, C. B. Lange, and B. J. Meggers Palaeoclimatic and archaeological evidence for a 200-yr recurrence of floods and droughts linking California, Mesoamerica and South America over the past 2000 years The Holocene, July 1, 2003; 13(5): 763 - 778. [Abstract] [PDF]
|
|
|
|
|
|
S.E. Ishman and M.R. Sperling Benthic foraminiferal record of Holocene deep-water evolution in the Palmer Deep, western Antarctic Peninsula Geology, May 1, 2002; 30(5): 435 - 438. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Taylor, F. Taylor, and A. McMinn Evidence from diatoms for Holocene climate fluctuation along the East Antarctic margin The Holocene, May 1, 2001; 11(4): 455 - 466. [Abstract] [PDF]
|
|
|
|
|
|
E. Domack, E. Domack, A. Leventer, R. Dunbar, F. Taylor, S. Brachfeld, and C. Sjunneskog Chronology of the Palmer Deep site, Antarctic Peninsula: a Holocene palaeoenvironmental reference for the circum-Antarctic The Holocene, January 1, 2001; 11(1): 1 - 9. [Abstract] [PDF]
|
|
|
|
|
|
E. Andren, T. Andren, and H. Kunzendorf Holocene history of the Baltic Sea as a background for assessing records of human impact in the sediments of the Gotland Basin The Holocene, September 1, 2000; 10(6): 687 - 702. [Abstract] [PDF]
|
|
|
|
|
|
J. Fabres, A. Calafat, M. Canals, M. A. Barcena, and J. A. Flores Bransfield Basin fine-grained sediments: late-Holocene sedimentary processes and Antarctic oceanographic conditions The Holocene, September 1, 2000; 10(6): 703 - 718. [Abstract] [PDF]
|
|
|
|
|
|
K. Holmgren, K. Holmgren, W. Karlen, S. E. Lauritzen, J. A. Lee-Thorp, T. C. Partridge, S. Piketh, P. Repinski, C. Stevenson, O. Svanered, et al. A 3000-year high-resolution stalagmitebased record of palaeoclimate for northeastern South Africa The Holocene, April 1, 1999; 9(3): 295 - 309. [Abstract] [PDF]
|
|
|
|
|
|
W. L. Cunningham, A. Leventer, J. T. Andrews, A. E. Jennings, and K. J. Licht Late Pleistocene-Holocene marine conditions in the Ross Sea, Antarctica: evidence from the diatom record The Holocene, February 1, 1999; 9(2): 129 - 139. [Abstract] [PDF]
|
|
|
|
|
|
E. W. Domack and P. A. Mayewski Bi-polar ocean linkages: evidence from late-Holocene Antarctic marine and Greenland ice-core records The Holocene, February 1, 1999; 9(2): 247 - 251. [Abstract] [PDF]
|
|
|
|
|
|
E. Andren, G. Shimmield, and T. Brand Environmental changes of the last three centuries indicated by siliceous microfossil records from the southwestern Baltic Sea The Holocene, January 1, 1999; 9(1): 25 - 38. [Abstract] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
