Consulta: subjectFacets:"Oxygenation"
Registros recuperados: 6
Data/hora: 13/06/2024 10:33:00

Stable isotopes in deep-sea living (stained) foraminifera from the Mozambique Channel (eastern Africa): multispecies signatures and paleoenvironmental application
Provedor de dados: 5
Autores: Fontanier, Christophe; Sakai, Saburo; Toyofuku, Takashi; Garnier, Eline; Brandily, Christophe; Eugene, Thibaut; Deflandre, Bruno.
Oxygen and carbon isotopes (δ18O and δ13C) have been investigated in carbonate tests of deep-sea foraminifera living in the Mozambique Channel (eastern Africa) to understand how environmental constraints (e.g., organic matter, oxygenation) control the intra- and interspecific variability of isotopic signatures. 197 living individuals, including eight different species, from various microhabitats within the sediment were sorted from sediment samples gathered at two stations on the Malagasy upper slope. Results show that the δ18O values of foraminiferal taxa were not controlled by microhabitat pattern. They presented tremendous and intriguing intraspecific variability that is not explained by the classical ontogenetic effect. The δ13C values of infaunal...
Tipo: Text
Palavras-chave: Oxygen and carbon isotopes; Deep-sea foraminifera; Organic matter; Oxygenation; Microhabitat.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00357/46831/46979.pdf

Long-term integrated biogeochemical budget driven by circulation in the eastern subpolar North Atlantic
Provedor de dados: 5
Autores: Fontela, Marcos; Mercier, Herle; Pérez, Fiz F.
The eastern subpolar North Atlantic (eSPNA) is a key region in the Atlantic Meridional Overturning Circulation (AMOC), playing an important role in biogeochemical cycles and climate regulation. Quantitative basin-scale biogeochemical budgets are still scarce despite the current need of establishing baselines of knowledge in a changing ocean. The physico-chemical data from the eight repetitions of the OVIDE section (2002-2016) are an unique opportunity to develop a novel evaluation of biogeochemical budgets in the eSPNA by combining robust and well established decadal mean mass transports with carbon variables, oxygen and inorganic nutrients in a full-depth inverse box model. The net balance between the carbon fixation and the respiration throughout the...
Tipo: Text
Palavras-chave: Subpolar North Atlantic; Biogeochemical cycles; Carbon cycle; Nutrient cycles; Oxygenation; Carbon sinks; Oceanic transports.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00480/59206/61898.pdf

Changes in Deep Water Oxygenation of the South China Sea Since the Last Glacial Period
Provedor de dados: 5
Autores: Li, Gang; Rashid, Harunur; Zhong, Lifeng; Xu, Xing; Yan, Wen; Chen, Zhong.
The Pacific meridional overturning circulation is thought to have a significant influence on global climate. However, the extent to which intermediate and deep circulations have changed in the Pacific Ocean since the Last Glacial Maximum (LGM) is not well known. At present, the South China Sea Deep Water (SCSDW) is fed by the upper Pacific Deep Water. Here we present new benthic foraminiferal C-13 and redox-sensitive elemental data from a sediment core retrieved from the southern deep SCS to reconstruct the oxygenation history of the SCSDW since the LGM. Oxygenation records from the deep SCS and intermediate and deep waters in the Pacific Ocean demonstrate that the SCSDW deeper than 1,600m has been sourced by the Pacific Deep Water since the LGM. Our data...
Tipo: Text
Palavras-chave: Redox-sensitive element; Oxygenation; Pacific Deep Water; South China Sea Deep Water; North Pacific Intermediate Water; Last glacial period.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00497/60817/64615.pdf

Foraminíferos bentónicos recientes en sedimentos de fondo de la cuenca de Panamá (Pacífico colombiano), como indicadores de productividad y oxigenación
Provedor de dados: 20
Autores: Betancur, M.J.; Martínez, I.
Thirteen deep-sea samples (core-tops) from the Panama Basin, Colombian Pacific, were analysed for benthonic foraminifera in the &gt;150μm size fraction. Based on the microfaunal content, three zones are recognised in the Panama Basin: (1) northern euphrophic region (~8º to 5,5ºN), characterized by a high concentration of organic matter flux to the seafloor, oxygenated sediments, and influence of the Panama Bight and the Costa Rica Dome upwelling systems, (2) mesotrophic region (~5,5 to 2ºN), characterized by low fluxes of organic carbon to the seafloor, oxygenated sediments, terrigenous influence and fluctuations of the upwelling systems of the basin, and (3) southern euphotic region (south of ~2ºN), characterized by a larger organic carbon flux to the...
Tipo: Journal Contribution
Palavras-chave: Foraminifera; Oxygenation.
Ano: 2003
URL: http://hdl.handle.net/1834/3111

Efeitos da aeração sobre as características da silagem de cana-de-açúcar - DOI: 10.4025/actasciagron.v31i2.7035
Provedor de dados: 1
Autores: Silva, Estela Jorge Alves da; USP; Borgatti, Laura Maria Oliveira; USP; Meyer, Paula Marques; IBGE; Rodrigues, Paulo Henrique Mazza; USP.
No presente estudo, objetivou-se avaliar os efeitos do tempo de aeração sobre as características nutricionais e fermentativas da silagem de cana-de-açúcar. Utilizou-se o delineamento inteiramente casualizado com três tratamentos e quatro repetições. A cana-de-açúcar recém-picada foi exposta à aeração por 0, 4 ou 8 horas, sendo ensilada somente após cada tempo de espera. Após a exposição, o material foi ensilado em 12 silos experimentais confeccionados de baldes plásticos. A abertura dos silos ocorreu 85 dias após a ensilagem. Foram determinados os teores dos ácidos orgânicos e a composição químico-bromatológica das silagens. Foi observado desvio da linearidade (p &lt; 0,05) do tempo de aeração sobre os teores de matéria seca e efeito linear crescente (p...
Palavras-chave: 5.01.00.00-9 Agronomia ensilagem; Fermentação; Forrageira; Oxigenação; Valor nutritivo ensiling; Fermentation; Forage; Nutritive value; Oxygenation.
Ano: 2009
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/7035

Influence of mass transfer on bubble plume hydrodynamics
Provedor de dados: 42
Autores: LIMA NETO,IRAN E.; PARENTE,PRISCILA A.B.
ABSTRACT This paper presents an integral model to evaluate the impact of gas transfer on the hydrodynamics of bubble plumes. The model is based on the Gaussian type self-similarity and functional relationships for the entrainment coefficient and factor of momentum amplification due to turbulence. The impact of mass transfer on bubble plume hydrodynamics is investigated considering different bubble sizes, gas flow rates and water depths. The results revealed a relevant impact when fine bubbles are considered, even for moderate water depths. Additionally, model simulations indicate that for weak bubble plumes (i.e., with relatively low flow rates and large depths and slip velocities), both dissolution and turbulence can affect plume hydrodynamics, which...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Aeration; Bubbles; Hydrodynamics; Mass transfer; Modeling; Oxygenation.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000100411