Laminated sediments in the Bering Sea reveal atmospheric teleconnections to Greenland climate on millennial to decadal timescales during the last deglaciation

Abstract

Abstract. During the last glacial termination, the upper North Pacific Ocean underwent dramatic and rapid changes in oxygenation that lead to the transient intensification of Oxygen Minimum Zones (OMZs), recorded by the widespread occurrence of laminated sediments on circum-Pacific continental margins. We present a new laminated sediment record from the mid-depth (1100 m) northern Bering Sea margin that provides insight into these deglacial OMZ maxima with exceptional, decadal-scale detail. Combined ultrahigh-resolution micro-XRF data and sediment facies analysis of laminae reveals an alternation between predominantly terrigenous and diatom-dominated opal sedimentation. The diatomaceous laminae are interpreted to represent spring/summer productivity events that occur at the retreating sea ice margin. We identified five laminated sections in the deglacial part of our site. Laminae counts were carried out on these sections and correlated to the Bølling–Allerød and Preboreal phases in North Greenland Ice Core (NGRIP) oxygen isotope record, indicating an annual deposition of individual laminae couplets. The observed rapid intra-decadal intensifications of anoxia, in particular within the Bølling–Allerød, are tightly coupled to short-term warm events through increases in regional biogenic productivity. By correlating the counted laminated sections with Bering Sea Surface Temperature records (SST) and NGRIP δ18O data, we propose a deglacial minimum SST of 6–7 °C for the preservation of laminae, which we call the deglacial temperature threshold for anoxia occurrence, a process that strongly implies a close atmospheric teleconnection between the North Pacific and North Atlantic regions. We suggest that concomitant increases in Bering Sea biogenic productivity, in combination with oxygen-poor waters entering the Being Sea, drove down oxygen concentrations to values below 0.1 mL L-1 and caused laminae preservation. Calculated benthic-planktic ventilation ages show no significant variations throughout the last deglaciation, indicating that changes in formation rates or differing sources of North Pacific mid-depth waters are not prime candidates for strengthening the OMZ at our site. The age models established by our correlation procedure allow to determine calendar age control points for the Bølling–Allerød and the Preboreal that are independent of the initial radiocarbon-based chronology. Resulting calculated reservoir ages are 875 yr during the Bølling–Allerød, and 910–770 yr for the Younger Dryas and the Preboreal, respectively.

Oceanographic and Climatic Change in the Bering Sea, Last Glacial Maximum to Holocene

“…A reservoir age of 800 years (Δ R 400) was chosen to be consistent with published studies of these cores (Brunelle et al, , ; Caissie et al, ; Cook et al, ), other proximal cores with calculated reservoir ages that range between 730 and 1,100 years near 3JPC (Itaki et al, ; Kim et al, ; Kuehn et al, ; Schlung et al, ), and the marine calibration data sets (http://calib.qub.ac.uk/marine/) (McNeely et al, ). However, this reservoir correction has been previously estimated to range between 460 to 1,100 years for total modern reservoir corrections (Dumond & Griffin, ; Gorbarenko et al, ; Kuzmin et al, ).…”

“…Here we use sedimentologic, geochemical, and isotopic evidence to build upon previous studies of the Bering Sea (e.g., Brunelle et al, ; Caissie et al, , ; Cook et al, ; Kuehn et al, ; Sancetta et al, ; Schlung et al, ), Gulf of Alaska (Addison et al, ; Barron et al, ; Davies et al, ), and North Pacific (Keigwin et al, ; Kohfeld & Chase, ; Lam et al, ). These studies focused on diatoms, radiolarians, foraminifera, alkenones, and stable isotopes as proxies for environmental change during the late Quaternary and Holocene.…”

“…Widespread deposition of laminations occurred in North Pacific sediments during the Bølling‐Allerød (14.9–12.9 ka) and Pre‐Boreal (~11.7–10.7 ka) (Mangerud et al, ; Van der Plicht et al, ) warm periods. The early Holocene was characterized globally by warmer temperatures (Meyer et al, ), and in the Bering Sea by increased productivity and laminated sediments (e.g., Kuehn et al, ). Laminations from these time periods are found along the northwest coast of Mexico (Ganeshram & Pedersen, ), Gulf of California (Barron et al, ; Keigwin, ; Sancetta, ), Santa Barbara Basin (Hendy & Kennett, ; Kennett & Ingram, ), California margin (Gardner et al, ; Mix et al, ), northwestern Pacific (Brunelle et al, ; Keigwin et al, ; Shibahara et al, ), Sea of Japan (Takahashi, ), and the Bering Sea (Brunelle et al, ; Caissie et al, ; Cook et al, ; Itaki et al, ; Khim et al, ; Kim et al, ; Kuehn et al, ; Okazaki et al, ; Schlung et al, ).…”

“…Laminated sediments are deposited under dysoxic to anoxic conditions (Behl & Kennett, ; Kennett & Ingram, ) with export productivity and ventilation controlling benthic oxygenation (Hendy & Pedersen, ). Laminated intervals in cores proximal to our Bering Sea sites have been attributed to changes in oxygen content of North Pacific Intermediate Water and increased export production, the combination of which fostered dysaerobic conditions, though much remains unknown about the relative importance of each forcing mechanism (Caissie et al, ; Cook et al, ; Davies et al, ; Kuehn et al, ; Schlung et al, ).…”

Modern modes of provenance and dispersal of terrigenous sediments in the North Pacific and Bering Sea: implications and perspectives for palaeoenvironmental reconstructions

“…This project seeks to fill gaps in palaeo-oceanographic knowledge in a sector of the world ocean critical for deciphering past and present global climate changes. Findings on modern and Quaternary sediment records based on an integrated approach merging traditional and novel methods can be found in several recent publications (Méheust et al 2013(Méheust et al , 2016Kuehn et al 2014;Ren et al 2014;Serno et al 2014;Maier et al 2015).…”