FN Archimer Export Format
PT J
TI Observations on the relationship between the Antarctic coastal diatoms Thalassiosira antarctica Comber and Porosira glacialis (Grunow) Jorgensen and sea ice concentrations during the late Quaternary
BT 
AF PIKE, Jennifer
   CROSTA, Xavier
   MADDISON, Eleanor J.
   STICKLEY, Catherine E.
   DENIS, Delphine
   BARBARA, Loic
   RENSSEN, Hans
AS 1:1;2:2;3:3;4:4,5;5:2;6:2;7:6;
FF 1:;2:;3:;4:;5:;6:;7:;
C1 Cardiff Univ, Sch Earth & Ocean Sci, Cardiff CF10 3YE, S Glam, Wales.
   Univ Bordeaux 1, CNRS, UMR EPOC 5805, F-33405 Talence, France.
   Open Univ, Dept Earth & Environm Sci, Milton Keynes MK7 6AA, Bucks, England.
   Univ Tromso, Dept Geol, N-9037 Tromso, Norway.
   Polar Environm Ctr, Norwegian Polar Inst, N-9296 Tromso, Norway.
   Vrije Univ Amsterdam, Dept Paleoclimatol & Geomorphol, Amsterdam, Netherlands.
C2 UNIV CARDIFF, UK
   UNIV BORDEAUX, FRANCE
   UNIV OPEN, UK
   UNIV TROMSO, NORWAY
   NORWEGIAN POLAR INST, NORWAY
   UNIV VRIJE AMSTERDAM, NETHERLANDS
IF 2.44
TC 50
UR https://archimer.ifremer.fr/doc/00220/33092/82663.pdf
LA English
DT Article
CR MD 130 / CADO
BO Marion Dufresne
DE ;East Antarctica;Quaternary;diatoms;sea ice
AB The available ecological and palaeoecological information for two sea ice-related marine diatoms (Bacillariophyceae), Thalassiosira antarctica Comber and Porosira glacialis (Grunow) Jorgensen, suggests that these two species have similar sea surface temperature (SST), sea surface salinity (SSS) and sea ice proximity preferences. From phytoplankton observations, both are described as summer or autumn bloom species, commonly found in low SST waters associated with sea ice, although rarely within the ice. Both species form resting spores (RS) as irradiance decreases, SST falls and SSS increases in response to freezing ice in autumn. Recent work analysing late Quaternary seasonally laminated diatom ooze from coastal Antarctic sites has revealed that sub-laminae dominated either by I antarctica RS, or by R glacialis RS, are nearly always deposited as the last sediment increment of the year, interpreted as representing autumn flux. In this study, we focus on sites from the East Antarctic margin and show that there is a spatial and temporal separation in whether T antarctica RS or P. glacialis RS form the autumnal sub-laminae. For instance, in deglacial sediments from the Mertz Ninnis Trough (George V Coast) P. glacialis RS form the sub-laminae whereas in similar age sediments from Iceberg Alley (Mac.Robertson Shelf) T antarctica RS dominate the autumn sub-lamina. In the Dumont d'Urville Trough (Adelie Land), mid-Holocene (Hypsithermal warm period) autumnal sub-laminae are dominated by T antarctica RS whereas late Holocene (Neoglacial cool period) sub-laminae are dominated by P. glacialis RS. These observations from late Quaternary seasonally laminated sediments would appear to indicate that P. glacialis prefers slightly cooler ocean-climate conditions than T antarctica. We test this relationship against two down-core Holocene quantitative diatom abundance records from Dumont d'Urville Trough and Svenner Channel (Princess Elizabeth Land) and compare the results with SST and sea ice concentration results of an Antarctic and Southern Ocean Holocene climate simulation that used a coupled atmosphere-sea ice-vegation model forced with orbital parameters and greenhouse gas concentrations. We find that abundance of P. glacialis RS is favoured by higher winter and spring sea ice concentrations and that a climatically-sensitive threshold exists between the abundance of P. glacialis RS and T antarctica RS in the sediments. An increase to >0.1 for the ratio of P. glacialis RS:T antarctica RS indicates a change to increased winter sea ice concentration (to >80% concentration), cooler spring seasons with increased sea ice, slightly warmer autumn seasons with less sea ice and a change from similar to 7.5 months annual sea ice cover at a site to much greater than 7.5 months. In the East Antarctic sediment record, an increase in the ratio from <0.1 to above 0.1 occurs at the transition from the warmer Hypsithermal climate into the cooler Neoglacial climate (similar to 4 cal kyr) indicating that the ratio between these two diatoms has the potential to be used as a semiquantitative climate proxy.
PY 2009
PD OCT
SO Marine Micropaleontology
SN 0377-8398
PU Elsevier Science Bv
VL 73
IS 1-2
UT 000271369000002
BP 14
EP 25
DI 10.1016/j.marmicro.2009.06.005
ID 33092
ER

EF