English abstract
We reconstructed the evolution of marine primary productivity across the last déglaciation in the Gulf of Aden based on micropaleontological and sedimentological data from marine core MD92-1002. Dinoflagellate cysts analysis suggests that the glacial period was characterized by weakened upwellings and well ventilated bottom water. Primary productivity increased from 14.5 ka with a maximum between 12.6 and 10.8 ka, then declined during the Holocene. Maximum of primary productivity in the Gulf of Aden took place about 3 ka earlier than the maximum of upwelling intensity off the Oman margin, and was not phase-locked with the maximum of boreal summer insolation. XRF-derived bromine contents mimic the variations of Total Organic Carbon (TOC) in core MD92-1002. Both records show a strong glacial/interglacial signal that is largely decoupled from our reconstruction of surface productivity, suggesting that total organic content in core MD92-1002 is mainly controlled by preservation at the sea floor.
