Mid Holocene origin of the sea-surface salinity low in the subarctic North Pacific

Sarnthein, Michael; Gebhardt, Holger; Kiefer, Thorsten; Kučera, Michal; Cook, Michael; Erlenkeuser, Helmut

doi:10.1016/j.quascirev.2004.08.008

Cited by 43 publications

(43 citation statements)

References 32 publications

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“…Vertical mixing of oligotrophic surface water with nutrient-enriched waters from below is most important. During late to present Holocene times this nutrient source appears to be largely barred by almost stable stratification of subpolar waters [Clarke et al, 2001;Sarnthein et al, 2004], even more so during the last glacial [Keigwin et al, 1992]. Nevertheless, despite stratification, the modern pycnocline appears to tap directly into nutrient-rich waters from the deep ocean, in particular Pacific Deepwater upwelled in the northwestern North Pacific [Tsunogai, 2002;Sarmiento et al, 2004].…”

Section: Discussionmentioning

confidence: 99%

“…In contrast to the first model this process will lead to reversed THC in the far northwestern Pacific Ocean, a scenario recently confirmed by extremely low planktic and benthic 14 C reservoir ages in the subarctic North Pacific for most of Termination Ia and later on [Sarnthein et al, 2007[Sarnthein et al, , 2004. Modern stable stratification in the subarctic Pacific Ocean may thus have been replaced by vertical mixing and intensified downwelling over distinct time intervals 17.5 -11.0 ka, coeval with Heinrich 1 (H1), Bølling-Allerød (B/A), and Younger Dryas (YD) to earliest Holocene times.…”

Section: Introductionmentioning

confidence: 85%

“…The benthic record in Core MD01-2416 was generated using Uvigerina spp. (mainly U. senticosta and U. hispida), since this genus occurs continuously throughout the core (data from Sarnthein et al [2004Sarnthein et al [ , 2005, supplemented). However, Uvigerina is too scarce for generating a continuous record in Core MD02-2489.…”

Section: Stable Oxygen and Carbon Isotopesmentioning

confidence: 99%

“…Mg/Ca ratios were converted into paleotemperatures of late spring and late summer (G. Haug, personal communication, 2007) using the species-specific calibration of Elderfield and Ganssen [2000]. Replicate analyses resulted in a reproducibility of approximately ±0.8°C (details of uncertainty are given by Sarnthein et al [2004]). …”

Section: Sea Surface Temperature and Sea Surface Salinitymentioning

confidence: 99%

“…and its Mg/Ca ratio are formed, may exceed the possibly systematic errors from using an Atlantic database for the North Pacific. The SIMMAX transfer function apparently is strongly muting any short-term SST oscillations [Sarnthein et al, 2004].…”

Section: Sea Surface Temperature and Sea Surface Salinitymentioning

confidence: 99%

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Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Gebhardt¹,

Sarnthein²,

et al. 2008

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[1] Our study addresses fundamental questions of the mode and timing of orbital and millennial-scale changes in the meridional overturning circulation (MOC) of the subarctic North Pacific. Particular concerns are the vertical mixing, the present and past abundance of nutrients in surface waters despite strong stratification, and the North Pacific-North Atlantic seesaw of oscillations in sea surface temperature (SST). We do this by generating and interpreting multiple records for glacial terminations I-V down two long piston cores, one each from the western and eastern subarctic Pacific. Chlorins and biogenic opal are proxies for surface water productivity; d 13 C of epibenthic foraminifera is a record of deepwater ventilation; and the d 13 C of N. pachyderma sin. is a tracer of nutrients in subsurface waters that extend up to the sea surface during times of vertical mixing. The degree of mixing is traced by pairing SST and d 18 O records of planktic surface and subsurface (pycnocline) dwellers. Tight age control is deduced from a suite of age-calibrated 14 C plateau boundaries for Termination I and benthic d 18 O and geomagnetic events for the last 800 ka. Carbon 14 paleoreservoir ages record the ages of surface and deep waters to uncover short-term changes in MOC over Termination I. We have defined a standard sequence of short-term productivity events for Termination I, also evident during terminations II to V and subsequent interglacials over the last 450 ka. The peak glacial regime of stable stratification and low productivity terminated, together with the end of ice rafting and melting, near 17 ka, $2000 years after the onset of Termination I. Pulses of vertical mixing and incursion of warm surface waters from the subtropics followed. Convected young water masses finally penetrated down to 3600-m water depth at 17.0 to less than 14.5 ka, significantly improving bottom water ventilation through the late deglacial and earliest interglacial. Mixing with upwelled nutrients from the pycnocline induced short-term maxima in algal production of chlorins and biogenic opal near 17-15 and 15-12 ka, respectively. Deglacial meltwater incursions in the Aleutian Current and silica input from North American rivers also promoted East Pacific productivity after 15.5 ka. Productivity decreased during the late deglacial and early interglacial, coeval with an exceptional peak in CaCO 3 preservation caused by both low organic flux and well-ventilated deepwater. Subsequently, low salinity and cool surface waters and in turn, stratification were gradually restored. A second, opaldominated productivity maximum marked the ends of interglacials. The deglacial pulses of vertical mixing around 17-11 ka imply an important contribution of the North Pacific to the coeval release of oceanic CO 2 into the atmosphere and support the east-west seesaw model of climate change.Citation: Gebhardt, H., M. Sarnthein, P. M. Grootes, T. Kiefer, H. Kuehn, F. Schmieder, and U. Röhl (2008), Paleonutrient and productivity records from the subarctic North ...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 85%

Section: Stable Oxygen and Carbon Isotopesmentioning

confidence: 99%

Section: Sea Surface Temperature and Sea Surface Salinitymentioning

confidence: 99%

Section: Sea Surface Temperature and Sea Surface Salinitymentioning

confidence: 99%

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Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Gebhardt¹,

Sarnthein²,

et al. 2008

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Comparing dust flux records from the Subarctic North Pacific and Greenland: Implications for atmospheric transport to Greenland and for the application of dust as a chronostratigraphic tool

et al. 2015

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We present a new record of eolian dust flux to the western Subarctic North Pacific (SNP) covering the past 27,000 years based on a core from the Detroit Seamount. Comparing the SNP dust record to the North Greenland Ice Core Project (NGRIP) ice core record shows significant differences in the amplitude of dust changes to the two regions during the last deglaciation, while the timing of abrupt changes is synchronous. If dust deposition in the SNP faithfully records its mobilization in East Asian source regions, then the difference in the relative amplitude must reflect climate-related changes in atmospheric dust transport to Greenland. Based on the synchronicity in the timing of dust changes in the SNP and Greenland, we tie abrupt deglacial transitions in the 230 Th-normalized 4 He flux record to corresponding transitions in the well-dated NGRIP dust flux record to provide a new chronostratigraphic technique for marine sediments from the SNP. Results from this technique are complemented by radiocarbon dating, which allows us to independently constrain radiocarbon paleoreservoir ages. We find paleoreservoir ages of 745 ± 140 years at 11,653 year B.P., 680 ± 228 years at 14,630 year B.P., and 790 ± 498 years at 23,290 year B.P. Our reconstructed paleoreservoir ages are consistent with modern surface water reservoir ages in the western SNP. Good temporal synchronicity between eolian dust records from the Subantarctic Atlantic and equatorial Pacific and the ice core record from Antarctica supports the reliability of the proposed dust tuning method to be used more widely in other global ocean regions.

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Deglacial subarctic Pacific surface water hydrography and nutrient dynamics and links to North Atlantic climate variability and atmospheric CO₂

et al. 2015

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The glacial-to-Holocene evolution of subarctic Pacific surface water stratification and silicic acid (Si) dynamics is investigated based on new combined diatom oxygen (δ 18 O diat ) and silicon (δ 30 Si diat ) isotope records, along with new biogenic opal, subsurface foraminiferal δ 18 O, alkenone-based sea surface temperature, sea ice, diatom, and core logging data from the NE Pacific. Our results suggest that δ 18 O diat values are primarily influenced by changes in freshwater discharge from the Cordilleran Ice Sheet (CIS), while corresponding δ 30 Si diat are primarily influenced by changes in Si supply to surface waters. Our data indicate enhanced glacial to mid Heinrich Stadial 1 (HS1) NE Pacific surface water stratification, generally limiting the Si supply to surface waters. However, we suggest that an increase in Si supply during early HS1, when surface waters were still stratified, is linked to increased North Pacific Intermediate Water formation. The coincidence between fresh surface waters during HS1 and enhanced ice-rafted debris sedimentation in the North Atlantic indicates a close link between CIS and Laurentide Ice Sheet dynamics and a dominant atmospheric control on CIS deglaciation. The Bølling/Allerød (B/A) is characterized by destratification in the subarctic Pacific and an increased supply of saline, Si-rich waters to surface waters. This change toward increased convection occurred prior to the Bølling warming and is likely triggered by a switch to sea ice-free conditions during late HS1. Our results furthermore indicate a decreased efficiency of the biological pump during late HS1 and the B/A (possibly also the Younger Dryas), suggesting that the subarctic Pacific has then been a source region of atmospheric CO 2 .

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Mid Holocene origin of the sea-surface salinity low in the subarctic North Pacific

Cited by 43 publications

References 32 publications

Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Comparing dust flux records from the Subarctic North Pacific and Greenland: Implications for atmospheric transport to Greenland and for the application of dust as a chronostratigraphic tool

Deglacial subarctic Pacific surface water hydrography and nutrient dynamics and links to North Atlantic climate variability and atmospheric CO₂

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Mid Holocene origin of the sea-surface salinity low in the subarctic North Pacific

Cited by 43 publications

References 32 publications

Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Comparing dust flux records from the Subarctic North Pacific and Greenland: Implications for atmospheric transport to Greenland and for the application of dust as a chronostratigraphic tool

Deglacial subarctic Pacific surface water hydrography and nutrient dynamics and links to North Atlantic climate variability and atmospheric CO2

Contact Info

Product

Resources

About

Deglacial subarctic Pacific surface water hydrography and nutrient dynamics and links to North Atlantic climate variability and atmospheric CO₂