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Orbital-scale climate forcing of grassland burning in southern Africa ArchiMer
Daniau, Anne-laure; Goni, Maria Fernanda Sanchez; Martinez, Philippe; Urrego, Dunia H.; Bout-roumazeilles, Viviane; Desprat, Stephanie; Marlon, Jennifer R..
Although grassland and savanna occupy only a quarter of the world's vegetation, burning in these ecosystems accounts for roughly half the global carbon emissions from fire. However, the processes that govern changes in grassland burning are poorly understood, particularly on time scales beyond satellite records. We analyzed microcharcoal, sediments, and geochemistry in a high-resolution marine sediment core off Namibia to identify the processes that have controlled biomass burning in southern African grassland ecosystems under large, multimillennial-scale climate changes. Six fire cycles occurred during the past 170,000 y in southern Africa that correspond both in timing and magnitude to the precessional forcing of north-south shifts in the Intertropical...
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Ano: 2013 URL: https://archimer.ifremer.fr/doc/00181/29235/27640.pdf
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Position of the Polar Front along the western Iberian margin during key cold episodes of the last 45 ka ArchiMer
Eynaud, Frederique; De Abreu, Lucia; Voelker, Antje; Schoenfeld, Joachim; Salgueiro, Emilia; Turon, Jean-louis; Penaud, Aurelie; Toucanne, Samuel; Naughton, Filipa; Goni, Maria Fernanda Sanchez; Malaize, Bruno; Cacho, Isabel.
This paper documents the migration of the Polar Front (PF) over the Iberian margin during some of the cold climatic extremes of the last 45 ka. It is based on a compilation of robust and coherent paleohydrological proxies obtained from eleven cores distributed between 36 and 42 degrees N. Planktonic delta O-18 (Globigerina bulloides), ice-rafted detritus concentrations, and the relative abundance of the polar foraminifera Neogloboquadrina pachyderma sinistral were used to track the PF position. These three data sets, compared from core to core, show a consistent evolution of the sea surface paleohydrology along the Iberian margin over the last 45 ka. We focused on five time slices representative of cold periods under distinct paleoenvironmental forcings:...
Tipo: Text Palavras-chave: Polar Front; LGM; Heinrich events.
Ano: 2009 URL: https://archimer.ifremer.fr/doc/00218/32909/31415.pdf
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Orbital- and sub-orbital-scale climate impacts on vegetation of the western Mediterranean basin over the last 48,000 yr ArchiMer
Fletcher, William J.; Goni, Maria Fernanda Sanchez.
High-resolution pollen analysis of Alboran Sea Core MD95-2043 provides a 48-ka continuous vegetation record that can be directly correlated with sea surface and deep-water changes. The reliability of this record is supported by comparison with that of Padul (Sierra Nevada, Spain). Marine Isotope Stage (MIS) 3 was characterised by fluctuations in Quercus forest cover in response to Dansgaard-Oeschger climate variability. MIS 2 was characterised by the dominance of semi-desert vegetation. Despite overall dry and cold conditions during MIS 2, Heinrich events (HEs) 2 and 1 were distinguished from the last glacial maximum by more intensely and conditions. Taxon-specific vegetation responses to a tripartite climatic structure within the HEs are observed. In MIS...
Tipo: Text Palavras-chave: Marine palynology; Land-sea correlation; Iberian margin; Mediterranean region; Dansgaard-Oeschger variability; Heinrich events; LGM; Holocene; Precession.
Ano: 2008 URL: https://archimer.ifremer.fr/doc/00237/34783/33369.pdf
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Testing the Hypothesis of Fire Use for Ecosystem Management by Neanderthal and Upper Palaeolithic Modern Human Populations ArchiMer
Daniau, Anne-laure; D'Errico, Francesco; Goni, Maria Fernanda Sanchez.
Background: It has been proposed that a greater control and more extensive use of fire was one of the behavioral innovations that emerged in Africa among early Modern Humans, favouring their spread throughout the world and determining their eventual evolutionary success. We would expect, if extensive fire use for ecosystem management were a component of the modern human technical and cognitive package, as suggested for Australia, to find major disturbances in the natural biomass burning variability associated with the colonisation of Europe by Modern Humans. Methodology/Principal Findings: Analyses of microcharcoal preserved in two deep-sea cores located off Iberia and France were used to reconstruct changes in biomass burning between 70 and 10 kyr cal BP....
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Ano: 2010 URL: https://archimer.ifremer.fr/doc/00231/34242/32652.pdf
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