Millennial-scale paleoceanographic events and implication for the intermediate-water ventilation in the northern slope area of the Bering Sea during the last 71kyrs

Orbital-scale benthic foraminiferal oxygen isotope stratigraphy at the northern Bering Sea Slope Site U1343 (IODP Expedition 323) and its Pleistocene paleoceanographic significance

“…Semi-perennial sea-ice cover over the Bering Sea Slope during glacial periods is consistent with previously published sea-ice reconstructions during the LGM at the Bering Sea Slope (Katsuki and Takahashi, 2005;Kim et al, 2011;Rella et al, 2012) and the Umnak Plateau (Cassie et al, 2010), and suggests that the extensive sea-ice cover over the Bering Sea documented previously only for the last glacial cycle first appeared during glacials at ~0.9 Ma.…”

“…The first relates to the biological response during the deglaciation, and the second relates to the evolution of sea-ice at the Bering Sea Slope and related sedimentation. Notably, high biological production during the last deglacial period has been reported along the northern margin of the North Pacific including the Bering Sea (Cook et al, 2005, Gebhardt et al, 2008, Gorbarenko et al, 2002, Kim et al 2011, Okazaki et al, 2006Ono et al, 2005;Schulung et al, 2012). This significant increase in biological production during the deglaciation is also confirmed by the coexistence of the laminated sediments at the same horizons (Cook et al, 2005;Kim et al, 2011).…”

“…Notably, high biological production during the last deglacial period has been reported along the northern margin of the North Pacific including the Bering Sea (Cook et al, 2005, Gebhardt et al, 2008, Gorbarenko et al, 2002, Kim et al 2011, Okazaki et al, 2006Ono et al, 2005;Schulung et al, 2012). This significant increase in biological production during the deglaciation is also confirmed by the coexistence of the laminated sediments at the same horizons (Cook et al, 2005;Kim et al, 2011). At Site U1343, a total of nine laminated intervals were recognized (at 10.2, 13.4, 14.1, 132, 144, 179, 424, 495 and1266 ka, Takahashi et al, 2011).…”

Pulses of enhanced North Pacific Intermediate Water ventilation from the Okhotsk Sea and Bering Sea during the last deglaciation

“…Past changes in intermediate-depth oxygen concentrations in the northwest Pacific are often related to a substantial weakening of NPIW and its consequences in favoring the expansion of the oxygen minimum zone at the intermediate-water level (Schmittner et al, 2007;Cartapanis et al, 2011). During the Bølling/Allerød and early Holocene, hypoxic conditions marked the oceanic continental margins in the North Pacific, as well as in the Bering Sea and culminated in the formation of laminated sediments in some of those regions (Behl and Kennett, 1996;Cook et al, 2005;Kim et al, 2011). Under modern conditions, the Okhotsk Sea plays a central role as major contributor of fresh intermediate-water masses in the subarctic Pacific, physically coupled to sea-ice formation (Talley and Roemmich, 1991;Warner et al, 1996;Yasuda, 1997).…”

Centennial to millennial climate variability in the far northwestern Pacific (off Kamchatka) and its linkage to the East Asian monsoon and North Atlantic from the Last Glacial Maximum to the early Holocene

“…The sequence of abrupt warming and environmental ameliorations similar to DO interstadials in Greenland were also interpreted by using alkenone-derived SST (Harada et al, 2008) and geochemical, diatom and pollen data (Gorbarenko et al, 2004) in sediment cores investigated from the Okhotsk Sea. The Bering Sea was also characterized by climate and environmental oscillations corresponding to DO cycles based on productivity proxies, sediment density, opal content and micropaleontological records Kim et al, 2011;Riethdorf et al, 2013;Schlung et al, 2013).…”