Oceanographic variability across the mid-Pleistocene Transition at the Agulhas Plateau

The Agulhas Current, a western boundary current that transports heat and salinity from the Indian into the Atlantic Ocean through the Agulhas Leakage, plays a key role in global ocean circulation and climate. However, efforts to better understand the mechanisms driving changes at the Indian-Atlantic Ocean gateway across major climate transitions, such as the mid-Pleistocene transition (MPT), are limited. The Agulhas Plateau is located at the Agulhas retroflection pathway, an area affected by latitudinal migrations of the subtropical front and provide a strategic location to study the effects of the establishment of high amplitude 100-kyr glacial-interglacial cycles during the MPT. Using sediments recovered at IODP site 1475 on the Agulhas Plateau, we present new records of water temperature (U^k'₃₇ and TEX₈₆), primary productivity (chlorins and alkenones), and sea surface salinity (δD_alkenones), spanning from 1.2 to 0.3 Ma. Our multiproxy reconstructions highlight glacial-interglacial periodicity, showing more abrupt and higher amplitude cycles after the MPT from which we infer changes in Agulhas Current strength and leakage variability. Following the MPT, offsets between the two water temperature proxies during glacials and interglacials suggest varying contributions of regional water masses at Agulhas Plateau.