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| Max, Lars; Riethdorf, Jan-rainer; Tiedemann, Ralf; Smirnova, Maria; Lembke-jene, Lester; Fahl, Kirsten; Nuernberg, Dirk; Matul, Alexander; Mollenhauer, Gesine. |
| Past changes in North Pacific sea surface temperatures and sea-ice conditions are proposed to play a crucial role in deglacial climate development and ocean circulation but are less well known than from the North Atlantic. Here, we present new alkenone-based sea surface temperature records from the subarctic northwest Pacific and its marginal seas (Bering Sea and Sea of Okhotsk) for the time interval of the last 15 kyr, indicating millennial-scale sea surface temperature fluctuations similar to short-term deglacial climate oscillations known from Greenland ice core records. Past changes in sea-ice distribution are derived from relative percentage of specific diatom groups and qualitative assessment of the IP25 biomarker related to sea-ice diatoms. The... |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00265/37630/36988.pdf |
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| Riethdorf, Jan-rainer; Max, Lars; Nuernberg, Dirk; Lembke-jene, Lester; Tiedemann, Ralf. |
| Based on models and proxy data, it has been proposed that salinity-driven stratification weakened in the subarctic North Pacific during the last deglaciation, which potentially contributed to the deglacial rise in atmospheric carbon dioxide. We present high-resolution subsurface temperature (T-Mg/Ca) and subsurface salinity-approximating (delta O-18(ivc-sw)) records across the last 20,000 years from the subarctic North Pacific and its marginal seas, derived from combined stable oxygen isotopes and Mg/Ca ratios of the planktonic foraminiferal species Neogloboquadrina pachyderma (sin.). Our results indicate regionally differing changes of subsurface conditions. During the Heinrich Stadial 1 and the Younger Dryas cold phases, our sites were subject to reduced... |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00262/37307/35719.pdf |
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| Ronge, Thomas A.; Steph, Silke; Tiedemann, Ralf; Prange, Matthias; Merkel, Ute; Nuernberg, Dirk; Kuhn, Gerhard. |
| Glacial/interglacial changes in Southern Ocean's air-sea gas exchange have been considered as important mechanisms contributing to the glacial/interglacial variability in atmospheric CO2. Hence, understanding past variability in Southern Ocean intermediate to deep water chemistry and circulation is fundamental to constrain the role of these processes on modulating glacial/interglacial changes in the global carbon cycle. Our study focused on the glacial/interglacial variability in the vertical extent of southwest Pacific Antarctic Intermediate Water (AAIW). We compared carbon and oxygen isotope records from epibenthic foraminifera of sediment cores bathed in modern AAIW and Upper Circumpolar Deep Water (UCDW; 943–2066 m water depth) to monitor changes in... |
| Tipo: Text |
Palavras-chave: AAIW; UCDW; SW-Pacific; Stable isotopes. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00294/40568/39465.pdf |
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| Zuraida, Rina; Holbourn, Ann; Nuernberg, Dirk; Kuhnt, Wolfgang; Duerkop, Anke; Erichsen, A.. |
| We present sea surface and upper thermocline temperature records (60-100 year temporal resolution) spanning marine isotope stage 3 (similar to 24-62 ka B. P.) from International Marine Global Change Study core MD01-2378 (121 degrees 47.27'E and 13 degrees 04.95'S; 1783 m water depth) located in the outflow area of the Indonesian Throughflow within the Timor Sea. Stable isotopes and Mg/Ca of the near-surface-dwelling planktonic foraminifer Globigerinoides ruber (white) and the upper thermocline-dwelling Pulleniatina obliquiloculata reveal rapid changes in the thermal structure of the upper ocean during Heinrich events. Thermocline warming and increased delta O-18(seawater) (P. obliquiloculata record) during Heinrich events 3, 4, and 5 reflect weakening of... |
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| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32940/31434.pdf |
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