Consulta: subjectFacets:"Planktic foraminifera"
Registros recuperados: 4
Data/hora: 11/06/2024 18:35:58

Climatic evolution of the central equatorial Pacific since the Last Glacial Maximum
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Seo, Inah; Lee, Yuri; Lee, Yong Il; Yoo, Chan Min; Hyeong, Kiseong.
This paper investigates paleoceanographic changes at a central equatorial Pacific site (6 degrees 40N, 177 degrees 28W) since the last glacial maximum using planktic foraminifera assemblages, together with the oxygen isotope (O-18) and Mg/Ca compositions of three species (Globigerinoides sacculifer, Pulleniatina obliquiloculata, and Globorotalia tumida) that dwell in the mixed layer, upper thermocline, and lower thermocline, respectively. While the Mg/Ca-derived temperatures of the mixed layer and lower thermocline varied within a narrow range from 18 ka onward, the upper thermocline temperature increased by as much as 3 degrees C during the last deglaciation (18-12 ka) with a simultaneous decrease of O-18. These changes are best explained by an enhanced...
Tipo: Text
Palavras-chave: Planktic foraminifera; Geochemistry; Micropaleontology; Paleoceanography; Intertropical Convergence Zone; Last deglaciation.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00496/60721/65271.pdf

Flux dynamics of planktic foraminiferal tests in the south-eastern Bay of Biscay (northeast Atlantic margin)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Kuhnt, Tanja; Howa, Helene; Schmidt, Sabine; Marie, Louis; Schiebel, Ralf.
The temporal and water depth related dynamics of planktic foraminiferal fluxes in the south-eastern Bay of Biscay are discussed for a two year sampling period (June 2006-June 2008). Two sediment traps deployed at 800 m and 1700 m water depth at a mooring in 2000 m of water depth, were analyzed for the flux of planktic foraminiferal species &gt;150 mu m, in comparison with the total mass flux. Total flux of planktic foraminifera shows seasonal maxima in spring/early summer (&gt;2000 Ind.m(-2) d(-1)) and minima from late summer through winter (&lt;10 Ind.m(-2) d(-1)). The flux of planktic foraminiferal tests in the intermediate to deep water column at the inner Bay of Biscay comprises an intermittent and regionally variable signal of seasonal surface water...
Tipo: Text
Palavras-chave: Planktic foraminifera; Bay of Biscay; Sediment traps; Particulate mass flux; Pb-210; Seasonality; Lateral advection.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00125/23593/21785.pdf

Deglacial-Holocene environmental changes at the Pacific entrance of the Strait of Magellan
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

PLANKTIC FORAMINIFERAL DIVERSITY: LOGISTIC GROWTH OVERPRINTED BY A VARYING ENVIRONMENT
Provedor de dados: Acta Biológica Colombiana
Autores: CÁRDENAS-ROZO,Andrés L; HARRIES,Peter J.
This study statistically assesses the relationship between the planktic foraminiferal long-term diversity pattern (~170 Ma to Recent) and four major paleobiological diversification models: (i) the 'Red Queen' (Van Valen, 1973; Raup et al., 1973), (ii) the turnover-pulse (Vrba, 1985; Brett and Baird, 1995), (iii) the diversity-equilibrium (Sepkoski, 1978; Rosenzweig, 1995), and (iv) the 'complicated logistic growth' (Alroy, 2010a). Our results suggest that the long-term standing diversity pattern and the interplay between origination and extinction rates displayed by this group do not correspond to the first three models, but can be more readily explained by the fourth scenario. Consequently, these patterns are likely controlled by a combination of planktic...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Abiotic and biotic controls; Complicated logistic growth; Diversity dynamics; Macroevolution; Planktic foraminifera; Paleobiology.
Ano: 2016
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2016000300005