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| Gu, Sifan; Liu, Zhengyu; Zhang, Jiaxu; Rempfer, Johannes; Joos, Fortunat; Oppo, Delia W.. |
| Antarctic Intermediate Water (AAIW) plays important roles in the global climate system and the global ocean nutrient and carbon cycles. However, it is unclear how AAIW responds to global climate changes. In particular, neodymium isotopic composition (epsilon(Nd)) reconstructions from different locations from the tropical Atlantic have led to a debate on the relationship between northward penetration of AAIW into the tropical Atlantic and the Atlantic meridional overturning circulation (AMOC) variability during the last deglaciation. We resolve this controversy by studying the transient oceanic evolution during the last deglaciation using a neodymium-enabled ocean model. Our results suggest a coherent response of AAIW and AMOC: when AMOC weakens, the... |
| Tipo: Text |
Palavras-chave: AAIW; AMOC; Deglacial; Neodymium isotope; Paleocirculation tracer. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00495/60709/65334.pdf |
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| Gibbons, Fern T.; Oppo, Delia W.; Mohtadi, Mahyar; Rosenthal, Yair; Cheng, Jun; Liu, Zhengyu; Linsley, Braddock K.. |
| Evidence from geologic archives suggests that there were large changes in the tropical hydrologic cycle associated with the two prominent northern hemisphere deglacial cooling events, Heinrich Stadial 1 (HS1; similar to 19 to 15 kyr BP; kyr BP = 1000 yr before present) and the Younger Dryas (similar to 12.9 to 11.7 kyr BP). These hydrologic shifts have been alternatively attributed to high and low latitude origin. Here, we present a new record of hydrologic variability based on planktic foraminifera-derived delta O-18 of seawater (delta O-18(sw)) estimates from a sediment core from the tropical Eastern Indian Ocean, and using 12 additional delta O-18(sw) records, construct a single record of the dominant mode of tropical Eastern Equatorial Pacific and... |
| Tipo: Text |
Palavras-chave: Indo-Pacific; Eastern Equatorial Pacific; Delta O-18 of seawater; Deglaciation; Heat transport. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00496/60737/65207.pdf |
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| Schmittner, Andreas; Bostock, Helen C.; Cartapanis, Olivier; Curry, William B.; Filipsson, Helena L.; Galbraith, Eric D.; Gottschalk, Julia; Carlos Herguera, Juan; Hoogakker, Babette; Jaccard, Samuel L.; Lisiecki, Lorraine E.; Lund, David C.; Martinez-mendez, Gema; Lynch-stieglitz, Jean; Mackensen, Andreas; Michel, Elisabeth; Mix, Alan C.; Oppo, Delia W.; Peterson, Carlye D.; Repschlaeger, Janne; Sikes, Elisabeth L.; Spero, Howard J.; Waelbroeck, Claire. |
| The carbon isotope composition (C-13) of seawater provides valuable insight on ocean circulation, air-sea exchange, the biological pump, and the global carbon cycle and is reflected by the C-13 of foraminifera tests. Here more than 1700 C-13 observations of the benthic foraminifera genus Cibicides from late Holocene sediments (C-13(Cibnat)) are compiled and compared with newly updated estimates of the natural (preindustrial) water column C-13 of dissolved inorganic carbon (C-13(DICnat)) as part of the international Ocean Circulation and Carbon Cycling (OC3) project. Using selection criteria based on the spatial distance between samples, we find high correlation between C-13(Cibnat) and C-13(DICnat), confirming earlier work. Regression analyses indicate... |
| Tipo: Text |
Palavras-chave: Carbon; Isotopes; Benthic; Foraminifera; Calibration. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00661/77326/78788.pdf |
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| Irvali, Nil; Ninnemann, Ulysses S.; Galaasen, Eirik V.; Rosenthal, Yair; Kroon, Dick; Oppo, Delia W.; Kleiven, Helga F.; Darling, Kate F.; Kissel, Catherine. |
| At the peak of the previous interglacial period, North Atlantic and subpolar climate shared many features in common with projections of our future climate, including warmer-than-present conditions and a diminished Greenland Ice Sheet (GIS). Here we portray changes in North Atlantic hydrography linked with Greenland climate during Marine Isotope Stage (MIS) 5e using (sub)centennially sampled records of planktonic foraminiferal isotopes and assemblage counts and ice-rafted debris counts, as well as modern analog technique and Mg/Ca-based paleothermometry. We use the core MD03-2664 recovered from a high accumulation rate site (similar to 34 cm/kyr) on the Eirik sediment drift (57 degrees 26.34'N, 48 degrees 36.35'W). The results indicate that surface waters... |
| Tipo: Text |
Palavras-chave: Eirik Drift; MIS 5e; North Atlantic; Last interglacial; Multiproxy. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00139/25046/23154.pdf |
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| Oppo, Delia W.; Schmidt, Gavin A.; Legrande, Allegra N.. |
| [1] Paleoceanographic data from the low latitude Pacific Ocean provides evidence of changes in the freshwater budget and redistribution of freshwater within the basin during the Holocene. Reconstructed Holocene seawater delta O-18 changes compare favorably to differences predicted between climate simulations for the middle Holocene (MH) and for the pre-Industrial late Holocene (LH). The model simulations demonstrate that changes in the tropical hydrologic cycle affect the relationship between delta(18)Osw and surface salinity, and allow, for the first time, quantitative estimates of western Pacific salinity change during the Holocene. The simulations suggest that during the MH, the mean salinity of the Pacific was higher because less water vapor was... |
| Tipo: Text |
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| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00496/60755/65133.pdf |
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