Changes in bottom water oxygen level of the Arabian Sea and the driving factors since the Last Glacial Period

Variations in the oxygen content of water column in the Arabian Sea since the Last Glacial Period have significant differences in space and time. However, regarding the spatial variation patterns and dominating factors, systematic studies are scarce, especially on the mechanism of changes in oxygen content in deep water and the controlling factors on a millennial scale. Based on XRF core scanning results from two cores, WIND-CJ06-6 and WIND-CJ06-13, in the central deep water of the Arabian Sea and previously published data, we reconstructed the processes and analyzed the drivers of the variations in oxygen content in the Arabian Sea in different areas and depths on millennial scale since the Last Glacial Period. Results show that the variations in oxygen content in the Arabian Sea in water depths less than 1500 m on the millennial scale are controlled jointly by the surface primary productivity and mesopelagic water fluxes, and the dominant factors varied in different periods. Surface productivity in the northwestern part of the Arabian Sea was significantly higher than that in the rest of the sea during the transition period from B/A (Bølling-Ållerød) to YD (Younger Dryas) events, resulting in spatial difference: the oxygen content in the intermediate water was high in the NW Arabian Sea but low in the rest of the sea. The oxygen content in water column in the Arabian Sea at depths greater than 1500 m was mainly controlled by the strength of the North Atlantic Deep Water (NADW) since the Last Glacial Maximum (LGM), and the oxygen content in water was significantly increased due to enhanced ventilation in the Southern Ocean from the LGM to the HS1 (Heinrich Stadial 1) stage.