Insolation dependence of the southeastern subtropical Pacific sea surface temperature over the last 400 kyrs

Calvo, Eva María; Pelejero, Carles; Herguera, Juan Carlos; Palanqués, Albert; Grimalt, Joan O.

doi:10.1029/2000gl012024

Cited by 29 publications

(32 citation statements)

References 25 publications

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“…Results for Y71-6-12P agree with previous alkenonebased estimates in the region (TG7, Calvo et al, 2001). Nevertheless, in view of prospects we document for nonthermal physiological impacts on U K 0 37 , and our inference based on ME/EE signatures that all ice-age samples from the region may have no modern ecological analogs, there is now legitimate reason to question the accuracy of LGM ÔcoolingÕ assessed by this method, which is much less than that inferred from foraminiferal species assemblages (Feldberg and Mix, 2003;Kucera et al, 2005) and somewhat less than that inferred from radiolarian species assemblages (Pisias and Mix, 1997).…”

Section: The Paleoceanographic Tallysupporting

confidence: 91%

Alkenone paleothermometry: Biological lessons from marine sediment records off western South America

Prahl

Mix

Sparrow

2006

Geochimica et Cosmochimica Acta

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Section: The Paleoceanographic Tallysupporting

confidence: 91%

Alkenone paleothermometry: Biological lessons from marine sediment records off western South America

Prahl

Mix

Sparrow

2006

Geochimica et Cosmochimica Acta

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“…Thus, a glacial northward shift of the EF would cause weaker meridional δ 18 O gradients because of minimum changes in SST and salinity within the cold tongue. Other eastern Pacific alkenone‐SST reconstructions [i.e., Calvo et al , 2001; Liu and Herbert , 2004; Horikawa et al , 2006; Pahnke et al , 2007; Koutavas and Sachs , 2008; Dubois et al , 2009], together with previous SST estimates based on marine microfossils [i.e., Pisias and Mix , 1997; Feldberg and Mix , 2003; Martínez et al , 2003], support this view by demonstrating that sites located south of the EF experienced stronger cooling during the LGM and stronger warming during the last deglaciation compared to sites located north of the EF.…”

Section: Resultsmentioning

confidence: 53%

“…The early warming during the glacial terminations is also observed in other tropical records (see review by Schneider et al [1999]) and has been suggested to be linked with low‐latitude insolation forcing. Elevated glacial SSTs during MIS 6 are also found at Site MD02‐2529 (Figure 5b) in the eastern Pacific cold tongue [ Calvo et al , 2001] and in many other Indian and Atlantic equatorial records (see review by Schneider et al [1999]). In contrast, EEP δ 18 O and Mg/Ca records of planktonic foraminifera suggest a colder MIS 6 in comparison with alkenone‐based SSTs with a cooling of similar magnitude to those found on the preceding and following glacial periods [e.g., Lea et al , 2000; Pena et al , 2008].…”

Section: Resultsmentioning

confidence: 97%

More humid interglacials in Ecuador during the past 500 kyr linked to latitudinal shifts of the equatorial front and the Intertropical Convergence Zone in the eastern tropical Pacific

et al. 2010

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[1] Studying past changes in the eastern equatorial Pacific Ocean dynamics and their impact on precipitation on land gives us insight into how the Intertropical Convergence Zone (ITCZ) movements and the El Niño-Southern Oscillation modulate regional and global climate. In this study we present a multiproxy record of terrigenous input from marine sediments collected off the Ecuadorian coast spanning the last 500 kyr. In parallel we estimate sea surface temperatures (SST) derived from alkenone paleothermometry for the sediments off the Ecuadorian coast and complement them with alkenone-based SST data from the Panama Basin to the north in order to investigate SST gradients across the equatorial front. Near the equator, today's river runoff is tightly linked to SST, reaching its maximum either during the austral summer when the ITCZ migrates southward or during El Niño events. Our multiproxy reconstruction of riverine runoff indicates that interglacial periods experienced more humid conditions than the glacial periods. The north-south SST gradient is systematically steeper during glacial times, suggesting a mean background climatic state with a vigorous oceanic cold tongue, resembling modern La Niña conditions. This enhanced north-south SST gradient would also imply a glacial northward shift of the Intertropical Convergence Zone at least in vicinity of the cold tongue: a pattern that has not yet been reproduced in climate models.

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“…It is interesting to note that considerably higher U 37 K′ temperature estimates for the penultimate, compared to the last deglacial, cycle have also been documented from various locations outside the Arabian Sea [ Calvo et al , 2001; Eglinton et al , 1992; Hinrichs et al , 1997; Schneider et al , 1996, 1999], placing this phenomenon on a global scale.…”

Section: Resultsmentioning

confidence: 99%

Western Arabian Sea SST during the penultimate interglacial: A comparison of U₃₇^K′ and Mg/Ca paleothermometry

et al. 2009

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[1] Millennial-scale records of planktonic foraminiferal Mg/Ca, bulk sediment U 37 K 0 , and planktonic foraminiferal d 18 O are presented across the last two deglaciations in sediment core NIOP929 from the Arabian Sea. Mg/Ca-derived temperature variability during the penultimate and last deglacial periods falls within the range of modern day Arabian Sea temperatures, which are influenced by monsoon-driven upwelling. The U 37 K 0 -derived temperatures in MIS 5e are similar to modern intermonsoon values and are on average 3.5°C higher than the Mg/Ca temperatures in the same period. MIS 5e U 37and Mg/Ca temperatures are 1.5°C warmer than during the Holocene, while the U 37 K 0 -Mg/Ca temperature difference was about twice as large during MIS 5e. This is surprising as, nowadays, both proxy carriers have a very similar seasonal and depth distribution. Partial explanations for the MIS 5e U 37 K 0 -Mg/Ca temperature offset include carbonate dissolution, the change in dominant alkenone-producing species, and possibly lateral advection of alkenone-bearing material and a change in seasonal or depth distribution of proxy carriers. Our findings suggest that (1) Mg/Ca of G. ruber documents seawater temperature in the same way during both studied deglaciations as in the present, with respect to, e.g., season and depth, and (2) U 37 K 0 -based temperatures from MIS 5 (or older) represent neither upwelling SST nor annual average SST (as it does in the present and the Holocene) but a higher temperature, despite alkenone production mainly occurring in the upwelling season. Further we report that at the onset of the deglacial warming, the Mg/Ca record leads the U 37 K 0 record by 4 ka, of which a maximum of 2 ka may be explained by postdepositional processes. Deglacial warming in both temperature records leads the deglacial decrease in the d 18 O profile, and Mg/Ca-based temperature returns to lower values before d 18 O has reached minimum interglacial values. This indicates a substantial lead in Arabian Sea warming relative to global ice melting.

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Insolation dependence of the southeastern subtropical Pacific sea surface temperature over the last 400 kyrs

Cited by 29 publications

References 25 publications

Alkenone paleothermometry: Biological lessons from marine sediment records off western South America

Alkenone paleothermometry: Biological lessons from marine sediment records off western South America

More humid interglacials in Ecuador during the past 500 kyr linked to latitudinal shifts of the equatorial front and the Intertropical Convergence Zone in the eastern tropical Pacific

Western Arabian Sea SST during the penultimate interglacial: A comparison of U₃₇^K′ and Mg/Ca paleothermometry

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Insolation dependence of the southeastern subtropical Pacific sea surface temperature over the last 400 kyrs

Cited by 29 publications

References 25 publications

Alkenone paleothermometry: Biological lessons from marine sediment records off western South America

Alkenone paleothermometry: Biological lessons from marine sediment records off western South America

More humid interglacials in Ecuador during the past 500 kyr linked to latitudinal shifts of the equatorial front and the Intertropical Convergence Zone in the eastern tropical Pacific

Western Arabian Sea SST during the penultimate interglacial: A comparison of U37K′ and Mg/Ca paleothermometry

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Western Arabian Sea SST during the penultimate interglacial: A comparison of U₃₇^K′ and Mg/Ca paleothermometry