Age and stable isotopic record of high and lower latitude of the Pacific

DOI

The Eastern Equatorial Pacific (EEP) is a key area to understand past oceanic processes that control atmospheric CO2 concentrations. Many studies argue for higher nutrient concentrations by enhanced nutrient transfer via Southern Ocean Intermediate Water (SOIW) to the low-latitude Pacific during glacials. Recent studies, however, argue against SOIW as the primary nutrient source, at least during early Marine Isotope Stage 2 (MIS 2), as proxy-data indicate that nutrients are better utilized in the Southern Ocean under glacial conditions. New results from the subarctic Pacific suggest that enhanced convection of nutrient-rich Glacial North Pacific Intermediate Water (GNPIW) contributes to changes in nutrient concentrations in equatorial sub-thermocline water masses during MIS 2. However, the interplay between SOIW versus GNPIW and its influence on the nutrient distribution in the EEP spanning more than one glacial cycle are still not understood. We present a carbon isotope (d13C) record of sub-thermocline waters derived from deep-dwelling planktonic foraminifera Globorotaloides hexagonus in the EEP, which is compared with published d13C records around the Pacific. Results indicate enhanced influence of GNPIW during MIS 6 and MIS 2 compared to today with largest contributions of northern-sourced intermediate waters during glacial maxima. These observations suggest a mechanistic link between relative contributions of northern and southern intermediate waters and past EEP nutrient concentrations. A switch from increased GNPIW (decreased SOIW) to diminished GNPIW (enhanced SOIW) influence on equatorial sub-thermocline waters is recognized during glacial terminations and marks changes to modern-like conditions in nutrient concentrations and biological productivity in the EEP.

Supplement to: Rippert, Nadine; Max, Lars; Mackensen, Andreas; Cacho, Isabel; Povea, Patricia; Tiedemann, Ralf (2017): Alternating influence of northern versus southern-sourced water masses on the equatorial Pacific subthermocline during the past 240 ka. Paleoceanography, 32(11), 1256-1274

Identifier
DOI https://doi.org/10.1594/PANGAEA.882520
Related Identifier https://doi.org/10.1002/2017PA003133
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.882520
Provenance
Creator Rippert, Nadine ORCID logo; Max, Lars ORCID logo; Mackensen, Andreas ORCID logo; Cacho, Isabel ORCID logo; Povea, Patricia ORCID logo; Tiedemann, Ralf ORCID logo
Publisher PANGAEA
Publication Year 2017
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 5 datasets
Discipline Earth System Research
Spatial Coverage (-86.463W, -42.308S, 169.876E, 54.828N)
Temporal Coverage Begin 2002-05-16T00:00:00Z
Temporal Coverage End 2006-01-28T06:10:00Z