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| Grelaud, Michael; Marino, Gianluca; Ziveri, Patrizia; Rohling, Eelco J.. |
| A detailed assessment of the respective roles of production, export, and subsequent preservation of organic carbon (C-org) in the eastern Mediterranean (EMED) sediments during the formation of sapropels remains elusive. Here we present new micropaleontological results for both surface samples taken at several locations in the EMED and last interglacial sapropel S5 from core LC21 in the southeastern Aegean Sea. A strong exponential anticorrelation between relative abundances of the lower photic zone coccolithophore Florisphaera profunda in the surface sediments and modern concentrations of chlorophyll a (Chl-a) at the sea surface suggests that F. profunda percentages can be used to track past productivity changes in the EMED. Prior to S5 deposition, an... |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00265/37632/36756.pdf |
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| Chang, Liao; Bolton, Clara T.; Dekkers, Mark J.; Hayashida, Akira; Heslop, David; Krijgsman, Wout; Kodama, Kazuto; Paterson, Greig A.; Roberts, Andrew P.; Rohling, Eelco J.; Yamamoto, Yuhji; Zhao, Xiang. |
| We have identified millennial-scale variations in magnetic mineral diagenesis from Pacific Ocean sediments offshore of Japan that we correlate with changes in organic carbon burial that were likely driven by Asian monsoon fluctuations. The correlation was determined by identifying offsets between the positions of fossil diagenetic fronts and climatically induced variations in organic carbon burial inferred from magnetic and geochemical analyses. Episodes of intense monsoon activity and attendant sediment magnetic mineral diagenesis also appear to correlate with Heinrich events, which supports the existence of climatic telecommunications between Asia and the North Atlantic region. Several lines of evidence support our conclusions: (1) fluctuations in... |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00356/46703/47266.pdf |
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| Hansen, James; Kharecha, Pushker; Sato, Makiko; Masson-delmotte, Valerie; Ackerman, Frank; Beerling, David J.; Hearty, Paul J.; Hoegh-guldberg, Ove; Hsu, S; Parmesan, Camille; Rockstrom, Johan; Rohling, Eelco J.; Sachs, Jeffrey; Smith, Pete; Steffen, Konrad; Van Susteren, Lise; Von Schuckmann, Karina; Zachos, James C.. |
| We assess climate impacts of global warming using ongoing observations and paleoclimate data. We use Earth's measured energy imbalance, paleoclimate data, and simple representations of the global carbon cycle and temperature to define emission reductions needed to stabilize climate and avoid potentially disastrous impacts on today's young people, future generations, and nature. A cumulative industrial-era limit of similar to 500 GtC fossil fuel emissions and 100 GtC storage in the biosphere and soil would keep climate close to the Holocene range to which humanity and other species are adapted. Cumulative emissions of similar to 1000 GtC, sometimes associated with 2 degrees C global warming, would spur "slow" feedbacks and eventual warming of 3-4 degrees C... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00170/28092/26670.pdf |
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| Larrasoana, Juan C.; Roberts, Andrew P.; Rohling, Eelco J.. |
| Astronomically forced insolation changes have driven monsoon dynamics and recurrent humid episodes in North Africa, resulting in green Sahara Periods (GSPs) with savannah expansion throughout most of the desert. Despite their potential for expanding the area of prime hominin habitats and favouring out-of-Africa dispersals, GSPs have not been incorporated into the narrative of hominin evolution due to poor knowledge of their timing, dynamics and landscape composition at evolutionary timescales. We present a compilation of continental and marine paleoenvironmental records from within and around North Africa, which enables identification of over 230 GSPs within the last 8 million years. By combining the main climatological determinants of woody cover in... |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37476/36832.pdf |
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