FN Archimer Export Format
PT J
TI A multi-proxy analysis of Late Quaternary ocean and climate variability for the Maldives, Inner Sea
BT 
AF BUNZEL, Dorothea
   SCHMIEDL, Gerhard
   LINDHORST, Sebastian
   MACKENSEN, Andreas
   REOLID, Jesus
   ROMAHN, Sarah
   BETZLER, Christian
AS 1:1;2:1;3:1;4:2;5:1;6:1;7:1;
FF 1:;2:;3:;4:;5:;6:;7:;
C1 Univ Hamburg, Inst Geol, Ctr Earth Syst Res & Sustainabil CEN, D-20146 Hamburg, Germany.
   AWI, Helmholtz Ctr Polar & Marine Res, D-27568 Bremerhaven, Germany.
C2 UNIV HAMBURG, GERMANY
   INST A WEGENER, GERMANY
IN DOAJ
IF 3.174
TC 31
UR https://archimer.ifremer.fr/doc/00497/60823/64606.pdf
   https://archimer.ifremer.fr/doc/00497/60823/64607.pdf
LA English
DT Article
CR IMAGES 3-IPHIS-MD106
   MD 152 / MATACORE
BO Marion Dufresne
AB As a natural sediment trap, the marine sediments of the sheltered central part of the Maldives Inner Sea represent an exceptional archive for paleoenvironmental and climate changes in the equatorial Indian Ocean. To evaluate the complex interplay between high-latitude and monsoonal climate variability, related dust fluxes, and regional oceanographic responses, we focused on Fe/Al, Ti/Al and Si/Ca ratios as proxies for terrigenous sediment delivery and total organic carbon (TOC) and Br XRF counts as proxies for marine productivity. Benthic foraminiferal fauna distributions, grain size and stable delta O-18 and delta C-13 data were used for evaluating changes in the benthic ecosystem and changes in the intermediate water circulation, bottom water current velocity and oxygenation. Our multi-proxy data record reveals an enhanced dust supply during the glacial intervals, causing elevated Fe/Al and Si/Ca ratios, an overall coarsening of the sediment and an increasing amount of agglutinated benthic foraminifera. The enhanced dust fluxes can be attributed to higher dust availability in the Asian desert and loess areas and its transport by intensified winter monsoon winds during glacial conditions. These combined effects of wind-induced mixing of surface waters and dust fertilization during the cold phases resulted in an increased surface water productivity and related organic carbon fluxes. Thus, the development of highly diverse benthic foraminiferal faunas with certain detritus and suspension feeders was fostered. The difference in the delta C-13 signal between epifaunal and deep infaunal benthic foraminifera reveals intermediate water oxygen concentrations between approximately 40 and 100 mu mol kg(-1) during this time. The precessional fluctuation pattern of oxygen changes resembles that from the deep Arabian Sea, suggesting an expansion of the oxygen minimum zone (OMZ) from the Arabian Sea into the tropical Indian Ocean with a probable regional signal of strengthened winter-monsoon-induced organic matter fluxes and oxygen consumption further controlled by the varying inflow intensity of the Antarctic Intermediate Water (AAIW). In addition, the bottom water oxygenation pattern of the Maldives Inner Sea reveals a long phase of reduced ventilation during the last glacial period. This process is likely linked to the combined effects of generally enhanced oxygen consumption rates during high-productivity phases, reduced AAIW production and the restriction of upper bathyal environments in the Inner Sea during sea-level lowstands. Thus, our multi-proxy record reflects a close linkage between the Indian monsoon oscillation, intermediate water circulation, productivity and sea-level changes on orbital timescale. 
PY 2017
PD DEC
SO Climate Of The Past
SN 1814-9324
PU Copernicus Gesellschaft Mbh
VL 13
IS 12
UT 000417899200001
BP 1791
EP 1813
DI 10.5194/cp-13-1791-2017
ID 60823
ER

EF