Fig. 5: A schematic representation of the circulation changes and concomitant DSi distribution across the deglaciation. | Nature Communications

Fig. 5: A schematic representation of the circulation changes and concomitant DSi distribution across the deglaciation.

From: The nature of deep overturning and reconfigurations of the silicon cycle across the last deglaciation

Fig. 5

In each panel the upper (NADW/AAIW/SAMW) and lower (AABW/PDW/IDW) circulatory cells are depicted as blue and white arrows, respectively. The shading in each panel represents the concentration of DSi, with the LGM abyssal ocean being more DSi-rich than the modern as a result of reduced mixing. The dotted black line in each of the panels represents the isopycnal at divergence of the upper and lower circulatory cells54, the vertical position of which has been suggested to be governed by sea ice extent. Importantly, this schematic demonstrates that only when sea ice is sufficiently removed during the Younger Dryas are the deep Si-rich waters tapped into and redistributed into the upper circulatory cell. Southern Ocean and low latitude opal fluxes are globally generalised based on available data39,50,81.

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