The coupling of carbon cycle and AMOC - a multi-proxy study in the mid-depth subpolar North Atlantic since 65 ka

Abrupt climate oscillations during the last glaciation provide important insights for the ongoing rapid climate change. The strength and pattern of Atlantic Meridional Overturning Circulation (AMOC) are thought to play significant roles in the repeated millennial transitions between cold stadials and warm interstadials by distributing heat, water and carbon in the ocean. However, there is limited direct evidence for whether and how carbon cycle interacted with AMOC change at the intermediate water depth and on such a short timescale. In this study, we examined carbon cycle proxies at high resolution from a mid-depth subpolar North Atlantic core between 18 thousand and 65 thousand years ago and compared our record to AMOC proxies. Our results confirmed the close coupling of carbon cycle and AMOC, with depleted nutrient contents during weak AMOC intervals. We propose two AMOC settings that can reconcile literature and our data. Furthermore, we investigated the decoupling of carbon cycle and AMOC during deglacial. Our results suggest the decoupling was caused by North Atlantic’s timely response to sharp increase in atmospheric CO2.