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Registros recuperados: 7
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Atlantic Meridional Overturning Circulation during the Last Glacial and Deglacial: Inferences from the Atlantic Tropical Thermocline Temperature and Seawater Radiocarbon Activity ArchiMer
Huang, Enqing.
This thesis aims to investigate variations of the last glacial and deglacial Atlantic Ocean circulation, with emphasize on the Atlantic deepwater ventilation rate during the Last Glacial Maximum (LGM). The highlights of the thesis are as the followings: (1) the modern frontal zone between the North Atlantic and the South Atlantic central waters off NW Africa shifted to the south during the last glacial and deglacial time periods. (2) The radiocarbon-based circulation age of the deep Atlantic (> 1500 m) was estimated to be less than 400 years during the LGM, which was equal to or less than its pre-bomb value. Therefore, the LGM deep Atlantic was inferred to be well ventilated. (3) The abyssal Atlantic (below 2500 m) prior to the LGM was more depleted in...
Tipo: Text Palavras-chave: Climate change; Ocean circulation; Atlantic Ocean; Glacial; Deglacial; Thermocline; Radiocarbon; Global carbon cycle; Foraminifera; Carbonate; Trace elements; Deep ocean ventilation rates.
Ano: 2013 URL: https://archimer.ifremer.fr/doc/00493/60446/63891.pdf
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Biochar effect on the mineralization of soil organic matter. Repositório Alice
BRUUN, S.; EL-ZEHERY, T..
The objective of this work was to verify whether the addition of biochar to the soil affects the degradation of litter and of soil organic matter (SOM). In order to investigate the effect of biochar on the mineralization of barley straw, soil was incubated with 14C-labelled barley straw with or without unlabelled biochar. To investigate the effect of straw on the mineralization of biochar, soil was incubated with 14C-labelled biochar with or without straw. In addition, to investigate the effect of biochar on old SOM, a soil labelled by applying labelled straw 40 years ago was incubated with different levels of biochar. All experiments had a control treatment, without any soil amendment. The effect of biochar on the straw mineralization was small and...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Anthropogenic dark earth; Organic matter stability; Priming effect; Radiocarbon.
Ano: 2012 URL: http://www.alice.cnptia.embrapa.br/handle/doc/930311
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Biochar effect on the mineralization of soil organic matter PAB
Bruun,Sander; EL-Zehery,Tarek.
The objective of this work was to verify whether the addition of biochar to the soil affects the degradation of litter and of soil organic matter (SOM). In order to investigate the effect of biochar on the mineralization of barley straw, soil was incubated with 14C-labelled barley straw with or without unlabelled biochar. To investigate the effect of straw on the mineralization of biochar, soil was incubated with 14C-labelled biochar with or without straw. In addition, to investigate the effect of biochar on old SOM, a soil labelled by applying labelled straw 40 years ago was incubated with different levels of biochar. All experiments had a control treatment, without any soil amendment. The effect of biochar on the straw mineralization was small and...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Anthropogenic dark earth; Organic matter stability; Priming effect; Radiocarbon.
Ano: 2012 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2012000500005
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Black Sea "Lake" reservoir age evolution since the Last Glacial - Hydrologic and climatic implications ArchiMer
Soulet, Guillaume; Menot, Guillemette; Garreta, Vincent; Rostek, Frauke; Zaragosi, Sebastien; Lericolais, Gilles; Bard, Edouard.
Chronologies of sediments that document the last glacial history of the Black Sea "Lake" are hampered by issues relating to reservoir age. Regulated by basin hydrology, reservoir ages represent a tool that could potentially be used to better understand the response of Black Sea "Lake" hydrology to climate change. Therefore, deciphering reservoir age evolution is crucial both for better constraining the basin chronological framework and for providing new insights into our understanding of Black Sea "Lake" hydrology. By tuning a meaningful new high-resolution geochemical dataset (obtained from core MD04-2790) to a climate reference record, here, we propose a reliable chronology spanning the last 32 kyr BP. The chronology is compared to a large AMS...
Tipo: Text Palavras-chave: Black Sea; Reservoir age; Radiocarbon; Last Glacial; Last Deglaciation; Paleoclimate.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00043/15379/12817.pdf
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Glacial-to-deglacial 14C reservoir ages of surface and deep waters from the mid- and low-latitude Atlantic ArchiMer
Blamer, Sven.
The 14C reservoir age of ocean surface waters shows small-scale spatial and temporal variations. Accordingly, correct estimates of reservoir ages are crucial for any reconstruction of a precise radiocarbon-based chronology of marine sediments. To meet this target in the mid- and low- latitude Atlantic we obtained both 14C reservoir ages and an absolute age model for the glacial-to-deglacial sections of four marine sediment cores by means of the ‘14C Plateau Tuning Technique’. This method is independent of any common conversion scheme of 14C ages. The resulting empiric reservoir ages were compared with reservoir age estimates based on model simulations.
Tipo: Text Palavras-chave: Reservoir ages; Deep water ventilation ages; Atlantic; Radiocarbon.
Ano: 2016 URL: https://archimer.ifremer.fr/doc/00493/60445/63890.pdf
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New constraints on deglacial marine radiocarbon anomalies from a depth transect near Baja California ArchiMer
Lindsay, Colin M.; Lehman, Scott J.; Marchitto, Thomas M.; Carriquiry, Jose D.; Ortiz, Joseph D..
Previous studies have shown that radiocarbon activities (C-14) in the low-latitude, middepth Pacific and Indian Oceans were anomalously low during Heinrich Stadial 1 (HS1, similar to 17.8-14.6ka) and the Younger Dryas (YD, similar to 12.8-11.5ka), coincident with intervals of rising atmospheric CO2 concentration and declining atmospheric C-14. However, a full explanation of these events remains elusive due to sparse and sometimes conflicting data. Here we present new C-14 measurements on benthic and planktic foraminifera that, in combination with previously published measurements, enable us to reconstruct the C-14 depth gradient near Baja California. Vertical profiles were similar to present during the Last Glacial Maximum and BOlling/Allerod (14.6-12.8ka)...
Tipo: Text Palavras-chave: Radiocarbon; Deglaciation; Heinrich Stadial 1; Baja California; Benthic foraminifera.
Ano: 2016 URL: https://archimer.ifremer.fr/doc/00496/60797/64925.pdf
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Radiocarbon geochronology of the sediments of the São Paulo Bight (southern Brazilian upper margin) Anais da ABC (AABC)
Mahiques,Michel M.; Sousa,Silvia H.M.; Burone,Leticia; Nagai,Renata H.; Silveira,Ilson C.A.; Figueira,Rubens C.L.; Soutelino,Rafael G.; Ponsoni,Leandro; Klein,Daniel A..
The aim of this work was to generate an inventory of the data on radiocarbon datings obtained from sediments of the São Paulo Bight (southern Brazilian upper margin) and to analyze the data in terms of Late Quaternary sedimentary processes and sedimentation rates. A total of 238 radiocarbon datings from materials collected using differents ampling procedures was considered for this work. The sedimentation rates varied from less than 2 to 68 cm.kyr-1. The highest sedimentation rate values were found in a low-energy (ría type) coastal system as well as in the upwelling zones of Santa Catarina and Cabo Frio. The lowest rates were found on the outer shelf and upper slopes. Our results confirm the strong dependency of the shelf currents, with an emphasis to the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Continental margin; Quaternary; Radiocarbon; Sea-level; Sedimentation.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652011000300006
Registros recuperados: 7
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