Productivity changes in the Bering Sea during the late Quaternary

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

“…Previous piston core studies showed a large increase in the intensity of the OMZ during the last deglacial at Umnak Plateau (Okazaki et al, 2005), suggesting a relationship between productivity and terrestrial nutrient supply from melting ice and increased river input. However, there is no information regarding the longer timescale relationship through the Pleistocene.…”

“…Prior to IODP Expedition 323 (Exp 323 hereafter), little was known about the sedimentology and climate history of the Bering Sea outside of a few piston core studies (Cook et al, 2005;Okazaki et al, 2005;Katsuki and Takahashi, 2005;Takahashi et al, 2005) and Sites 188 and 185 (Scholl and Creager, 1973), which were drilled by the Deep Sea Drilling Project (DSDP) in 1971 with old drilling technology and poor recovery. 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.…”

Millennial-scale variability of marine productivity and terrigenous matter supply in the western Bering Sea over the past 180 kyr

“…Springer et al, 1996;Niebauer et al, 1999), it might have had a different influence on past oceanatmosphere CO 2 exchange. Paleoceanographic reconstructions in the Bering Sea also revealed reduced export production during the last glacial period, which increased during Termination I and remained high in the Holocene (Gorbarenko, 1996;Cook et al, 2005;Gorbarenko et al, 2005;Okada et al, 2005;Okazaki et al, 2005;Brunelle et al, 2007Brunelle et al, , 2010Itaki et al, 2009;Khim et al, 2010;Kim et al, 2011). This variability was explained by a complex interplay of changes in sea surface temperatures (SST), sea-ice coverage, inflow of Pacific surface waters, and upper-ocean stratification (e.g.…”

“…Recent progress has been made in detecting millennialscale climate variability in Bering Sea sediments (Cook et al, 2005;Gorbarenko et al, 2005Gorbarenko et al, , 2010Okazaki et al, 2005;Brunelle et al, 2010;Khim et al, 2010;Kim et al, 2011;Max et al, 2012;Rella et al, 2012). Most of these studies are restricted to the last ∼ 70 kyr or focus on deglacial changes in the northern, southern, and southeastern Bering Sea.…”

Expedition 323 summary

“…Prior to Integrated Ocean Drilling Program (IODP) Expedition 323, little was known about the sedimentology and climate history of the Bering Sea outside of a few piston core studies (e.g., Cook et al, 2005;Okazaki et al, 2005;Tanaka and Takahashi, 2005; and Deep Sea Drilling Project (DSDP) Sites 188 and 185 (Scholl and Creager, 1973), which were drilled in 1971 with old drilling technology and poor recovery. 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.…”