Tropical forcing of North Pacific intermediate water distribution during Late Quaternary rapid climate change?

IODP Expedition 323—Pliocene and Pleistocene Paleoceanographic Changes in the Bering Sea

“…Past studies using piston cores in the Bering Sea indicated that, while current conditions in the Bering Sea promote seasonal sea-ice formation, during the Last Glacial Maximum (LGM) conditions sustained perennial or nearly perennial sea-ice cover (Tanaka and Takahashi, 2005), attesting to the potential utility of sedimentary records in the Bering Sea to examine past sea-ice distributions. In paleoceanographic studies of the North Pacific, the Bering and Okhotsk seas have been implicated as sources of dense oxygenated intermediate water that possibly impacted oceanic and climate conditions throughout the Pacific on glacial-interglacial (Gorbarenko, 1996;Matsumoto et al, 2002) and millennial (Hendy and Kennett, 2003) timescales. In addition, changes in Bering Sea environmental conditions could be related to sea-level and circulation changes, which alter flow patterns through narrow straits that connect the Bering Sea to the Arctic Ocean to the north and the Pacific Ocean to the south.…”

Sediment geochemical records of productivity and oxygen depletion along the margin of western North America during the past 60,000 years: teleconnections with Greenland Ice and the Cariaco Basin

“…4). However, Hendy and Kennett (2003) state that during warm interstadials ''high productivity along the eastern Pacific margin recommenced, causing 'southern component' intermediate water to become suboxic as the organic material rain rate increased''. Also, maxima in the concentration of the upwelling foraminifer Globigerina bulloides during warm interstadials provide additional evidence for increased productivity.…”

“…The laminated intervals have been attributed to a warming of SST of as much as 5 1C within a few decades. Expansion of the subtropical high and contraction of the Aleutian low over the North Pacific permitted northward expansion of southern-sourced intermediate water that was oxygen deficient (Hendy and Kennett, 2003;Hendy and Pedersen, 2005). During cool stadials, the Aleutian low expanded bringing in more cool, well-oxygenated North Pacific Intermediate Water that was ventilated in the Sea of Okhotsk (Talley, 1991).…”

Expedition 323 summary

“…Past studies using piston cores in the Bering Sea indicate that although current conditions in the Bering Sea promote seasonal sea ice formation, during the Last Glacial Maximum (LGM), conditions sustained perennial or nearly pe-rennial sea ice cover , attesting to the potential usefulness of sedimentary records in the Bering Sea in examining sea ice distribution. In paleoceanographic studies in the North Pacific, the Bering and Okhotsk seas have been implicated as sources of dense, oxygenated intermediate water that possibly impacted oceanic and climate conditions throughout the Pacific on glacial-interglacial (e.g., Gorbarenko, 1996;Matsumoto et al, 2002) and millennial (e.g., Hendy and Kennett, 2003) timescales. In addition, changes in Bering Sea conditions could be related to sea level and circulation changes, which alter flow through small straits that connect the Bering Sea to the Arctic Ocean to the north and to the Pacific Ocean to the south.…”