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| Jaeschke, Andrea; Ziegler, Martin; Hopmans, Ellen C.; Reichart, Gert-jan; Lourens, Lucas J.; Schouten, Stefan; Damste, Jaap S. Sinninghe. |
| Anaerobic ammonium oxidation (anammox) has been recognized as an important process converting fixed nitrogen to N(2) in many marine environments, thereby having a major impact on the present-day marine nitrogen cycle. However, essentially nothing is known about the importance of anammox in past marine nitrogen cycles. In this study, we analyzed the distribution of fossil ladderane lipids, derived from bacteria performing anammox, in a sediment core from the northern Arabian Sea. Concentrations of ladderane lipids varied between 0.3 and 5.3 ng g(-1) sediment during the past 140 ka, with high values observed during the Holocene, intervals during the last glacial, and during the penultimate interglacial. Maxima in ladderane lipid abundances correlate with... |
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| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32942/31436.pdf |
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| Ziegler, Martin; Lourens, Lucas J.; Tuenter, Erik; Hilgen, Frits; Reichart, Gert-jan; Weber, Nanne. |
| Results from transient climate modeling experiments indicate an in-phase relationship between insolation forcing and Indian summer monsoonal precipitation. This is in contrast to high-resolution radioisotopically dated speleothem oxygen isotope (delta O-18) records of China, which showed that East Asian Monsoon maxima lag Northern Hemisphere peak summer insolation by similar to 2,700 years, while an approximately 8,000-year time lag was derived from late Pleistocene records of Arabian Sea sediments. Here, we evaluate the precession phase of the Arabian Sea signal by comparing a new high-resolution productivity and oxygen minimum zone (OMZ) intensity record from the Arabian Sea over the past 450,000 years with the results of a transient climate modeling... |
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| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34177/32908.pdf |
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| Kaboth-bahr, Stefanie; Bahr, Andre; Zeeden, Christian; Toucanne, Samuel; Eynaud, Frederique; Jimenez-espejo, Francisco; Rohl, Ursula; Friedrich, Oliver; Pross, Joerg; Lowemark, Ludvig; Lourens, Lucas J.. |
| The dynamics of Northern Hemisphere ice sheets during Late Quaternary glacials have yet been dominantly examined from a Laurentide Ice Sheet perspective, which helped shaping the idea of moisture-starved glacials and small-scale ice volume variability. However, the waxing and waning of the European Ice Sheet (EIS) casts doubt on this perception. Understanding EIS dynamics under glacial boundary conditions is crucial because its meltwater pulses influence global climate by weakening deepwater formation in the North Atlantic Ocean. Here we show that the advection of subtropical water toward the continental margin of western Europe lead to enhanced moisture availability on the continent and fueled the growth of EIS lobes during glacials. This warm-water... |
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Palavras-chave: Mediterranean Outflow variability; European Ice Sheet dynamics; Marine‐terrestrial feedback in the Euro‐Mediterranean realm; Glacial climate variability; Low‐latitude forcing of high‐latitude glaciations. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00457/56831/58657.pdf |
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