TY - JOUR
T1 - Variable North Atlantic climate seesaw patterns documented by a late Holocene marine record from Disko Bugt, West Greenland
AU - Seidenkrantz, Marit-Solveig
AU - Roncaglia, Lucia
AU - Fischel, Andrea
AU - Heilmann-Clausen, Claus
AU - Kuijpers, Antoon
AU - Moros, Matthias
N1 - Funding Information:
We would like to sincerely thank Jesper Olsen, Department of Earth Sciences, University of Aarhus, Denmark, for his help in constructing the age models for the two cores. 14 C datings were carried out at the Leibniz-Labor, Christian Albrechts Universität, Germany, the Poznan Radiocarbon Laboratory, Foundation of the Adam Mickiewicz University, Poland, the AMS laboratory, University of Aarhus, Denmark and the Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, California, USA. Palynomorph samples were prepared at the Geological Survey of Denmark and Greenland (GEUS). We are grateful to the master and crew of R/V Dana for ship operations during the cruise in summer 2000, and we would also like to express our thanks to Jack Schilling, Royal Netherlands Institute for Sea Research, and John Boserup (GEUS), who provided indispensable help with coring during the cruise. We would also like to acknowledge reviewer's comment by Elisabeth Levac and an unnamed reviewer. Part of the work was carried out as a Bachelor thesis by A. Fischel ( Fischel, 2006 ). This research was funded by the Carlsberg Foundation, Copenhagen (grant to L. Roncaglia), the Danish Natural Science Research Council (Danish Research Agency grants 9802945 and 9901443 to A. Kuijpers, and grant no. 21-04-0336 to A. Kuijpers and M.-S. Seidenkrantz), the European Union ‘PACLIVA’ (GEUS Contract EVR1-2002-000413), the Department of Earth Sciences, University of Aarhus, and GEUS.
PY - 2008/7
Y1 - 2008/7
N2 - The reconstruction of past sea-surface conditions in the Labrador Sea is essential for understanding climate fluctuations in the North Atlantic region. We here study late Holocene sea-surface conditions off West Greenland in order to elucidate the possible relationship between a North Atlantic seesaw and centennial to millennial-scale climate fluctuations in the Labrador Sea region. For that purpose we have studied the particulate organic matter (especially dinoflagellate cysts and acritarchs) from two marine sediment cores from Disko Bugt, central West Greenland. Our data show significant variations in sea-surface temperature and sea-ice cover during the last ca. 3200 years. After a cooling at ca. 2.9 ka cal. BP, presumably related to the Neoglacial cooling seen in large parts of the Northern Hemisphere, the area was subjected to significant variability both in the entrainment of Atlantic Water (West Greenland Current water) and in atmospheric temperatures. From 2.0-1.5 ka cal. BP corresponding to the later part of the 'Roman Warm Period', the area experienced a return to a stronger influx of Atlantic water and an increased fresh-water influx from land probably related to increased precipitation or to melt-water outflow from the nearby inland ice. The 'Dark Ages' (1.5-1.3 ka cal. BP) were characterised by an only minor cooling of the surface waters. However, as seen in other records from the Labrador Sea region, the beginning of the 'Medieval Warm Period' (1.3-0.9 ka cal. BP) signified a severe cooling presumably due to a significant reduction in Atlantic water entrainment. The cold conditions continued through the 'Little Ice Age' (after 0.9 ka cal. BP) although the area seems to have experienced a minor decrease in sea-ice cover until 0.5 ka cal. B.P., after which sea-ice cover may again have increased. The period of 'Modern Warming' is not represented in our data. Our study shows that a North Atlantic Oscillation-type pattern played a significant role in the late Holocene centennial to millennial-scale climate fluctuations in the Labrador Sea region. However, this cannot explain the full complexity of the climate signal. The fact that a simple pattern of 'cold' versus 'warm' climate scenario does not exist demonstrates that it will hardly be feasible to select the correct 'baseline' data set when modelling future climate development.
AB - The reconstruction of past sea-surface conditions in the Labrador Sea is essential for understanding climate fluctuations in the North Atlantic region. We here study late Holocene sea-surface conditions off West Greenland in order to elucidate the possible relationship between a North Atlantic seesaw and centennial to millennial-scale climate fluctuations in the Labrador Sea region. For that purpose we have studied the particulate organic matter (especially dinoflagellate cysts and acritarchs) from two marine sediment cores from Disko Bugt, central West Greenland. Our data show significant variations in sea-surface temperature and sea-ice cover during the last ca. 3200 years. After a cooling at ca. 2.9 ka cal. BP, presumably related to the Neoglacial cooling seen in large parts of the Northern Hemisphere, the area was subjected to significant variability both in the entrainment of Atlantic Water (West Greenland Current water) and in atmospheric temperatures. From 2.0-1.5 ka cal. BP corresponding to the later part of the 'Roman Warm Period', the area experienced a return to a stronger influx of Atlantic water and an increased fresh-water influx from land probably related to increased precipitation or to melt-water outflow from the nearby inland ice. The 'Dark Ages' (1.5-1.3 ka cal. BP) were characterised by an only minor cooling of the surface waters. However, as seen in other records from the Labrador Sea region, the beginning of the 'Medieval Warm Period' (1.3-0.9 ka cal. BP) signified a severe cooling presumably due to a significant reduction in Atlantic water entrainment. The cold conditions continued through the 'Little Ice Age' (after 0.9 ka cal. BP) although the area seems to have experienced a minor decrease in sea-ice cover until 0.5 ka cal. B.P., after which sea-ice cover may again have increased. The period of 'Modern Warming' is not represented in our data. Our study shows that a North Atlantic Oscillation-type pattern played a significant role in the late Holocene centennial to millennial-scale climate fluctuations in the Labrador Sea region. However, this cannot explain the full complexity of the climate signal. The fact that a simple pattern of 'cold' versus 'warm' climate scenario does not exist demonstrates that it will hardly be feasible to select the correct 'baseline' data set when modelling future climate development.
KW - climate seesaw
KW - dinoflagellates
KW - Disko Bugt
KW - Late Holocene
KW - palaeoceanography
KW - West Greenland
UR - http://www.scopus.com/inward/record.url?scp=48149113132&partnerID=8YFLogxK
U2 - 10.1016/j.marmicro.2008.01.006
DO - 10.1016/j.marmicro.2008.01.006
M3 - Article
VL - 68
SP - 66
EP - 83
JO - Marine Micropaleontology
JF - Marine Micropaleontology
SN - 0377-8398
IS - 1-2
ER -