CHANGES IN ARCTIC OCEAN PALEOPRODUCTIVITY AND HYDROGRAPHY DURING THE LAST 145 KYR: THE BENTHIC FORAMINIFERAL RECORD

Abstract

The benthic foraminiferal record of two sediment cores at 900 and 2500 m water depth in the marginal Arctic Ocean reflects fluctuations in paleoproductivity, ice sheet extent, and Atlantic water inflow. Highest paleoproductivity is observed in interglacial periods, and at the termination of interstadials to stadials within oxygen isotope substages (OIS) 6.3, 5.3, 5.1, 3.1, and Termination Ia. Stable and high paleoproductivity at the ice-edge during terminations is indicated by the Melonis zaandami benthic foraminiferal association. Periods of glacial ice sheet advance or retreat from the core site are dominated by benthic foraminiferal associations related to seasonal organic carbon flux. Temperate saline Atlantic water entered the Arctic Ocean within OIS 6.3, 5.5 and the Holocene. Coincident paleoproductivity maxima are related to extended seasonal ice retreat. During glacial periods of stagnating Atlantic water advection unusual low paleoproductivity values are observed in the Arctic Ocean, indicating increasing ice coverage. Deep water was poorly ventilated during these periods and the deeper site became exposed to corrosive bottom waters.