Sabiia Seb
PortuguêsEspañolEnglish
Embrapa
        Busca avançada

Botão Atualizar


Botão Atualizar

Ordenar por: 

RelevânciaAutorTítuloAnoImprime registros no formato resumido
Registros recuperados: 4
Primeira ... 1 ... Última
Imagem não selecionada

Imprime registro no formato completo
Freshwater impacts recorded in tetraunsaturated alkenones and alkenone sea surface temperatures from the Okhotsk Sea across millennial-scale cycles ArchiMer
Harada, Naomi; Sato, Miyako; Sakamoto, Tatsuhiko.
[1] We present records of phytoplankton-produced alkenones down a long piston core, which reveal changes of sea surface temperature (SST) and sea surface salinity (SSS) in the southwestern Okhotsk Sea over the past 120 ka. Between 20 and 60 ka B. P., alkenone-derived temperatures typically increased by 6 degrees C-8 degrees C from periods corresponding, within a few hundred years, to stadials to those corresponding to interstadials recorded in Greenland ice cores. The abundance of C-37:4 alkenone relative to total C37 alkenones (percent C-37:4), a possible proxy for salinity, indicated that during most low SSS was associated with high SST. The warm freshwater events might be related to ( 1) a decline in the supply of saline water entering the Okhotsk Sea...
Tipo: Text
Ano: 2008 URL: https://archimer.ifremer.fr/doc/00237/34826/33302.pdf
Imagem não selecionada

Imprime registro no formato completo
Deglacial-Holocene environmental changes at the Pacific entrance of the Strait of Magellan ArchiMer
Harada, Naomi; Ninnemann, Ulysses; Lange, Carina B.; Marchant, Margarita E.; Sato, Miyako; Ahagon, Naokazu; Pantoja, Silvio.
We show environmental and nitrogen cycle changes between 13 and 2.5 kyr BP (from the latest deglaciation to the Holocene) based on biogeochemical records in a sediment core from the Pacific entrance of the Strait of Magellan. Organic carbon, total nitrogen, and C-37 alkenone contents were low during 13-9 kyr BP but increased rapidly at 8 kyr BP. The relative contribution of tetra-unsaturated C-37 alkenone, used as a salinity proxy, suggests low salinity during 13-9 kyr BP changing to high salinity at 8 kyr BP. Planktic foraminifer data showed that Globigerina bulloides was more abundant during the deglacial-early Holocene than in the mid-late Holocene, whereas abundances of Neogloboquadrina pachyderma showed the opposite pattern. This evidence plus...
Tipo: Text Palavras-chave: Biogenic components; Delta C-13; Delta N-15; Planktic foraminifera; Alkenone; Sea surface temperature; Southern Patagonia.
Ano: 2013 URL: https://archimer.ifremer.fr/doc/00264/37548/36825.pdf
Imagem não selecionada

Imprime registro no formato completo
Glacial reduction and millennial-scale variations in Drake Passage throughflow ArchiMer
Lamy, Frank; Arz, Helge W.; Kilianc, Rolf; Lange, Carina B.; Lembke-jene, Lester; Wengler, Marc; Kaiser, Jerome; Baeza-urrea, Oscar; Hall, Ian R.; Harada, Naomi; Tiedemann, Ralf.
The Drake Passage (DP) is the major geographic constriction for the Antarctic Circumpolar Current (ACC) and exerts a strong control on the exchange of physical, chemical, and biological properties between the Atlantic, Pacific, and Indian Ocean basins. Resolving changes in the flow of circumpolar water masses through this gateway is, therefore, crucial for advancing our understanding of the Southern Ocean's role in global ocean and climate variability. Here, we reconstruct changes in DP throughflow dynamics over the past 65,000 y based on grain size and geochemical properties of sediment records from the southernmost continental margin of South America. Combined with published sediment records from the Scotia Sea, we argue for a considerable total...
Tipo: Text Palavras-chave: Paleoceanography; Drake Passage; Antarctic Circumpolar Current; Glacial-interglacial changes; Sedimentology.
Ano: 2015 URL: https://archimer.ifremer.fr/doc/00351/46233/46119.pdf
Imagem não selecionada

Imprime registro no formato completo
Abrupt changes of intermediate water properties on the northeastern slope of the Bering Sea during the last glacial and deglacial period ArchiMer
Rella, Stephan F.; Tada, Ryuji; Nagashima, Kana; Ikehara, Minoru; Itaki, Takuya; Ohkushi, Ken'Ichi; Sakamoto, Tatsuhiko; Harada, Naomi; Uchida, Masao.
Millennial-scale variability in the behavior of North Pacific Intermediate Water during the last glacial and deglacial period, and its association with Dansgaard-Oeschger (D-O) cycles and Heinrich events, are examined based on benthic foraminiferal oxygen and carbon isotopes (delta O-18(bf) and delta C-13(bf)) and %CaCO3 using a sediment core recovered from the northeastern slope of the Bering Sea. A suite of positive delta O-18(bf) excursions at intermediate depths of the Bering Sea, which seem at least in part associated with increases in the delta O-18(bf) gradients between the Bering and Okhotsk Seas, suggest the Bering Sea as a proximate source of intermediate water during several severe stadial episodes in the last glacial and deglacial period....
Tipo: Text
Ano: 2012 URL: https://archimer.ifremer.fr/doc/00265/37642/36754.pdf
Registros recuperados: 4
Primeira ... 1 ... Última
 

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Embrapa
Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC: https://www.embrapa.br/fale-conosco

Valid HTML 4.01 Transitional