Intermediate water ventilation change in the subarctic northwest Pacific during the last deglaciation

The laminated sediments suggest significant depletion in dissolved oxygen of intermediate water in the North Pacific during the last deglaciation. However, the cause of depleted oxygen during deglaciation is still a matter of debate. Here, we present foraminiferal Mg/Ca-based intermediate and surface temperatures and delta(18)O of seawater (delta(18)O(W); a proxy of salinity) in the Oyashio region in order to investigate intermediate water circulation through the last deglaciation. Results indicate that the intermediate water temperature and delta(18)O(W) increased in association with ventilation age at the Bolling-Allerod period, suggesting that the poor ventilation at that time. The surface record shows that the decrease of salinity preceded the slowdown of intermediate ventilation. The coupled variation of intermediate and surface water suggests that the supply of cold, fresh intermediate water diminished because of poor ventilation at the high latitude due to surface freshening. Citation: Sagawa, T., and K. Ikehara (2008), Intermediate water ventilation change in the subarctic northwest Pacific during the last deglaciation, Geophys. Res. Lett., 35, L24702, doi: 10.1029/2008GL035133.