Evidence for enhanced convection of North Pacific Intermediate Water to the low-latitude Pacific under glacial conditions.

Max, L., Rippert, N., Lembke-Jene, Lester, Cacho, I., Mackensen, A., Nürnberg, Dirk and Tiedemann, Ralf (2017) Evidence for enhanced convection of North Pacific Intermediate Water to the low-latitude Pacific under glacial conditions. Open Access Paleoceanography, 32 . pp. 41-55. DOI 10.1002/2016PA002994.

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Abstract

We provide high-resolution foraminiferal stable carbon isotope (δ13C) records from the subarctic Pacific and Eastern Equatorial Pacific (EEP) to investigate circulation dynamics between the extra-tropical and tropical North Pacific during the past 60 kyr. We measured the δ13C composition of the epibenthic foraminiferal species Cibicides lobatulus from a shallow sediment core recovered from the western Bering Sea (SO201-2-101KL; 58°52.52’N, 170°41.45’E; 630 m water depth) to reconstruct past ventilation changes close to the source region of Glacial North Pacific Intermediate Water (GNPIW). Information regarding glacial changes in the δ13C of sub-thermocline water masses in the EEP is derived from the deep-dwelling planktonic foraminifera Globorotaloides hexagonus at ODP Site 1240 (00°01.31’N, 82°27.76’W; 2921 m water depth). Apparent similarities in the long-term evolution of δ13C between GNPIW, intermediate waters in the eastern tropical North Pacific and sub-thermocline water masses in the EEP suggest the expansion of relatively 13C-depleted, nutrient-enriched, and northern-sourced intermediate waters to the equatorial Pacific under glacial conditions. Further, it appears that additional influence of GNPIW to the tropical Pacific is consistent with changes in nutrient distribution and biological productivity in surface-waters of the glacial EEP. Our findings highlight potential links between North Pacific mid-depth circulation changes, nutrient cycling, and biological productivity in the equatorial Pacific under glacial boundary conditions.

Document Type: Article
Keywords: North Pacific; Equatorial Pacific; stable isotopes; intermediate water; sub-thermocline; last glacial period
Research affiliation: Kiel University
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
AWI
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2016PA002994
ISSN: 0883-8305
Projects: REKLIM, MANIHIKI II, KALMAR, IODP
Expeditions/Models/Experiments:
Date Deposited: 23 Dec 2016 09:25
Last Modified: 23 Sep 2019 22:59
URI: http://oceanrep.geomar.de/id/eprint/35413

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