Consulta: subjectFacets:"Tracers"
Registros recuperados: 13
Data/hora: 05/06/2024 18:27:57

Modelling green macroalgal blooms on the coasts of Brittany, France to enhance water quality management
Provedor de dados: 5
Autores: Perrot, Thierry; Rossi, Nadege; Menesguen, Alain; Dumas, Franck.
First recorded in the 1970s, massive green macroalgal blooms have since become an annual recurrence in Brittany, France. Eutrophication (in particular to anthropogenic nitrogen input) has been identified as the main factor controlling Ulva ‘green tide’ events. In this study, we modelled Ulva proliferation using a two-dimensional model by coupling hydrodynamic and biological models (coined ‘MARS-Ulves’) for five sites along the Brittany coastline (La Fresnaye Bay, Saint-Brieuc Bay, Lannion Bay, Guissény Bay and Douarnenez Bay). Calibration of the biological model was mainly based on the seasonal variation of the maximum nitrogen uptake rate (VmaxN) and the half-saturation constant for nitrogen (KN) to reproduce the internal nutrient quotas measured in situ...
Tipo: Text
Palavras-chave: 2D model; Ulva; Eutrophication; Brittany coastal waters; Tracers; Nutrient reductions.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00171/28268/26517.pdf

Analysis of global surface ocean alkalinity to determine controlling processes
Provedor de dados: 5
Autores: Fry, Claudia H.; Tyrrell, Toby; Hain, Mathis P.; Bates, Nicholas R.; Achterberg, Eric P.
The export of calcium carbonate (CaCO3) from the surface ocean is poorly constrained. A better understanding of the magnitude and spatial distribution of this flux would improve our knowledge of the ocean carbon cycle and marine biogeochemistry. Here, we investigate controls over the spatial distribution of total alkalinity in the surface global ocean and produce a tracer for CaCO3 cycling. We took surface ocean bottle data for total alkalinity from global databases (GLODAP, CARINA, PACIFICA) and subtracted the effects of several processes: evaporation and precipitation, river discharge, and nutrient uptake and remineralization. The remaining variation in alkalinity exhibits a robust and coherent pattern including features of large amplitude and spatial...
Tipo: Text
Palavras-chave: Alkalinity; Calcium carbonate; Biogeochemical cycles; Tracers.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00292/40367/83011.pdf

Observations of Layering under a Warm-Core Ring in the Gulf of Mexico
Provedor de dados: 5
Autores: Meunier, Thomas; Pallas Sanz, Enric; Tenreiro, Miguel; Ochoa, Jose; Angulo, Angel Ruiz; Buckingham, Christian.
Two glider transects in the Gulf of Mexico reveal fine-vertical-scale thermohaline structures within a Loop Current eddy (LCE). Partially compensating temperature and salinity anomalies are shown to organize as thin layers below the eddy and near its edges. The anomalies have vertical scales ranging from 2 to 60 m and extend laterally over distances up to 120 km. These structures are evident in synthetic acoustic reflectivity derived from the glider data and are reminiscent of the intense layering observed in seismic imagery around meddies, Agulhas rings, and warm-core Kuroshio rings. The observed layers are aligned with the geostrophic streamfunction rather than isopycnals and develop preferentially in zones of intense vertical shear. These observations...
Tipo: Text
Palavras-chave: Eddies; Mesoscale processes; Small scale processes; In situ oceanic observations; Quasigeostrophic models; Tracers.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00600/71242/69612.pdf

A Software Package and Hardware Tools for in situ Experiments in a Lagrangian Reference Frame
Provedor de dados: 5
Autores: Doglioli, Andrea; Nencioli, Francesco; Petrenko, Anne; Rougier, Gilles; Fuda, Jean-luc; Grima, Nicolas.
The Lagrangian Transport Experiment (LATEX) was developed to study the influence of coupled physical and biogeochemical dynamics at the meso- and submesoscales on the transfers of matter and heat between the coastal zone and the open ocean. One of the goals of the Latex10 field experiment, conducted during September 2010 in the Gulf of Lion (northwest Mediterranean), was to mark a dynamical mesoscale feature by releasing a passive tracer [sulfur hexafluoride (SF6)] together with an array of Lagrangian buoys. The goal was to release the tracer in an initial patch as homogeneous as possible in the horizontal, and to study its turbulent mixing and dispersion while minimizing the contribution due to advection. For that, it was necessary to continuously adjust...
Tipo: Text
Palavras-chave: Dispersion; Lagrangian circulation; Transport; Ship observations; Tracers; Experimental design; Software.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00155/26590/24719.pdf

Biological and ecological factors related to trace element levels in harbour porpoises (Phocoena phocoena) from European waters
Provedor de dados: 5
Autores: Lahaye, V; Bustamante, Paco; Law, J.r; Learmonth, J.a; Santos, M.b.; Boon, J.p.; Rogan, E; Dabin, W; Addink, M.j.; Lopez, A; Zuur, A.f.; Pierce, G.j.; Caurant, Florence.
Selected trace elements (Cd, Cu, Hg, Se, Zn) were measured in the kidneys and the liver of 104 harbour porpoises (Phocoena phocoena) stranded along the coasts of France, Galicia (Spain), Ireland, Scotland (UK), and the Netherlands. Generally, relatively low concentrations of toxic elements were encountered in the tissues of European porpoises, except for two individuals, which displayed high hepatic Hg concentrations. Also, elevated Cd levels obtained in Scottish porpoises could be related to their feeding preferences and this result suggests an increase of the proportion of cephalopods in their diet with latitude. Moreover, significant geographical differences were seen in hepatic Zn concentrations; the elevated Zn concentrations displayed by porpoises...
Tipo: Text
Palavras-chave: Tracers; Multivariate analysis; Diet; Age; Marine mammals; Zinc; Cadmium; Mercury; Heavy metals.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2920.pdf

Distribution and behavior of dissolved hydrogen sulfide in hydrothermal plumes
Provedor de dados: 5
Autores: Radford Knoery, Joel; German, C; Charlou, Jean-luc; Donval, Jean-pierre; Fouquet, Yves.
Through the deep ocean, hydrothermal plumes disperse high concentrations of key chemical tracers including He-3, CH4, Mn, Fe, H2S, etc. This paper focuses on the distribution and behavior of total dissolved sulfide (sulfide hereafter) in hydrothermal plumes to show that its plume concentration decreases to subnanomolar a few kilometers from the vents. We also report on sulfide removal rates determined at in situ conditions; we observe that they are two orders of magnitude greater than for open ocean seawater, consistent with sulfide being detected only in the vicinity of hydrothermal vents. From our observations, we infer that the sole presence of sulfide in hydrothermal plumes locates active venting at the kilometer scale.
Tipo: Text
Palavras-chave: Chemical oceanography; Mid ocean ridges; Metals; Helium isotopes; Methane; Tracers; Hydrogen sulphide; Plumes; Hydrothermal activity.
Ano: 2001
URL: https://archimer.ifremer.fr/doc/2001/publication-688.pdf

Anthropogenic carbon distributions in the Atlantic Ocean: data-based estimates from the Arctic to the Antarctic
Provedor de dados: 5
Autores: Vazquez-rodriguez, Marcos; Touratier, Franck; Lo Monaco, Claire; Waugh, D. W.; Padin, X. A.; Bellerby, R. G. J.; Goyet, Catherine; Metzl, Nicolas; Rios, Aida F.; Perez, Fiz F.
Five of the most recent observational methods to estimate anthropogenic CO2 (C-ant) are applied to a high-quality dataset from five representative sections of the Atlantic Ocean extending from the Arctic to the Antarctic. Between latitudes 60 degrees N-40 degrees S all methods give similar spatial distributions and magnitude of C-ant. However, discrepancies are found in some regions, in particular in the Southern Ocean and Nordic Seas. The differences in the Southern Ocean have a significant impact on the anthropogenic carbon inventories. The calculated total inventories of C-ant for the Atlantic referred to 1994 vary from 48 to 67 Pg (10(15) g) of carbon, with an average of 54 +/- 8 Pg C, which is higher than previous estimates. These results, both the...
Tipo: Text
Palavras-chave: Deep equatorial atlantic; Northern indian-ocean; Water mass ages; CO2; Sea; Transport; Increase; Tracers; Models.
Ano: 2009
URL: https://archimer.ifremer.fr/doc/00202/31313/29724.pdf

Anthropogenic carbon distributions in the Atlantic Ocean: data-based estimates from the Arctic to the Antarctic
Provedor de dados: 5
Autores: Vazquez-rodriguez, M.; Touratier, F.; Lo Monaco, C.; Waugh, D. W.; Padin, X. A.; Bellerby, R. G. J.; Goyet, C.; Metzl, N.; Rios, A.f.; Perez, F.f.
Five of the most recent observational methods to estimate anthropogenic CO2 (Cant) are applied to a high-quality dataset from five representative sections of the Atlantic Ocean extending from the Arctic to the Antarctic. Between latitudes 60° N–40° S all methods give similar spatial distributions and magnitude of Cant. Conversely, large discrepancies are found in the Southern Ocean and Nordic Seas. The differences in the Southern Ocean have a significant impact on the anthropogenic carbon inventories. The calculated total inventories of Cant for the Atlantic referred to 1994 range from 48 to 67 Pg (1015 g) of carbon, with an average of 54±8 Pg C, which is higher than previous estimates. These results, both the detailed Cant distributions and extrapolated...
Tipo: Text
Palavras-chave: Deep equatorial atlantic; Northern indian-ocean; Water mass ages; CO2; Sea; Transport; Increase; Tracers; Models.
Ano: 2008
URL: https://archimer.ifremer.fr/doc/00293/40430/38984.pdf

Tracer stirring around a meddy: The formation of layering
Provedor de dados: 5
Autores: Meunier, Thomas; Menesguen, Claire; Schopp, Richard; Le Gentil, Sylvie.
The dynamics of the formation of layering surrounding meddy-like vortex lenses is investigated using primitive equation (PE), quasigeostrophic (QG), and tracer advection models. Recent in situ data inside a meddy confirmed the formation of highly density-compensated layers in temperature and salinity at the periphery of the vortex core. Very high-resolution PE modeling of an idealized meddy showed the formation of realistic layers even in the absence of double-diffusive processes. The strong density compensation observed in the PE model, in good agreement with in situ data, suggests that stirring might be a leading process in the generation of layering. Passive tracer experiments confirmed that the vertical variance cascade in the periphery of the vortex...
Tipo: Text
Palavras-chave: Circulation/ Dynamics; Advection; Dynamics; Atm/Ocean Structure/ Phenomena; Vortices; Models and modeling; Primitive equations model; Quasigeostrophic models; Tracers.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00255/36599/35160.pdf

Atlantic meridional overturning circulation and the Southern Hemisphere supergyre
Provedor de dados: 5
Autores: Speich, Sabrina; Blanke, Bruno; Cai, Wenju.
The ocean's role in climate manifests itself through its high heat capacity, its own rich internal dynamics and its ability to transport vast quantities of heat and freshwater. Of particular interest is the global ocean circulation associated with the Atlantic meridional overturning (AMOC). Because observations are sparse, the detailed global structure of the AMOC remains poorly understood, particularly the pathways along which water returns to the Atlantic to compensate the export of North Atlantic Deep Water (NADW). Here we provide the first quantitative 3-dimensional global view of the AMOC using a Lagrangian reconstruction which integrates hundred of thousands water particle trajectories in an ocean model. The resulting pattern elucidates the role of...
Tipo: Text
Palavras-chave: Antarctic circumpolar current; Indian ocean; Intermediate water; Thermohaline circulation; Pacific oceans; Conveyor belt; Model; Transport; Tracers.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00203/31420/29821.pdf

Avaliação da deposição da calda de pulverização em função da vazão e do tipo de bico hidráulico na cultura da soja - DOI: 10.4025/actasciagron.v30i2.1789
Provedor de dados: 1
Autores: Boschini, Laércio; UNIOESTE; Contiero, Robinson Luiz; Universidade Estadual do Oeste do Paraná.; Macedo Junior, Eurides Kuster; UNIOESTE; Guimarães, Vandeir Francisco; UNIOESTE.
O experimento foi conduzido no município de Cascavel, Estado do Paraná, com a cultivar de soja CD 202, com o objetivo de avaliar a quantidade de calda depositada nas folhas da soja. Foram coletadas amostras, contendo 15 folhas por parcela, em cinco plantas, em diferentes extratos, sendo uma folha do extrato inferior; uma, do mediano, e uma, do superior, com a finalidade de avaliar a deposição da calda de pulverização em função da vazão e do tipo de bico. Os tratamentos foram constituídos por quatro bicos de pulverização (leque simples, duplo leque, duplo leque com injeção de ar e cone vazio) e três volumes de calda (100, 200 e 300 L há-1). O volume de calda que apresentou maiores deposições, nos diferentes extratos das plantas de soja, foi o de 300 L há-1;...
Palavras-chave: 5.01.03.05-9 Melhoramento Vegetal tecnologia aplicação; Pontas; Bicos; Volume; Traçadores 5.01.03.05-9 Melhoramento Vegetal application technology; Tips; Nozzles; Volume; Tracers.
Ano: 2008
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/1789

Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview
Provedor de dados: 42
Autores: Alves,Célia A.
In spite of accounting for 10-70% of the atmospheric aerosol mass, particulate-phase organic compounds are not well characterised, and many aspects of aerosol formation and evolution are still unknown. The growing awareness of the impact of particulate aerosols on climate, and the incompletely recognised but serious effects of anthropogenic constituents on air quality and human health, have conducted to several scientific studies. These investigations have provided information about the behaviour of atmospheric particulate matter and the description of the character of its carbonaceous content. The compilation of such results is important as they append to the emergent global-wide dataset of the organic composition of atmospheric aerosols. The contribution...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Atmospheric aerosol; Gas chromatography-masss pectrometry; Organic compounds; Source apportionment; Tracers.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652008000100003

Hydrodynamic behavior of a combined anaerobic-aerobic system employed in the treatment of vinasse
Provedor de dados: 64
Autores: Fia,Fátima Resende Luiz; Fia,Ronaldo; Campos,Cláudio Milton Montenegro; Oliveira,Luiz Fernando Coutinho de.
ABSTRACT The understanding of reactor hydrodynamics is essential for improving the performance of a reactor and biogas production. This study sought to evaluate the hydrodynamic behavior of a combined anaerobic-aerobic system at a laboratory scale for treating vinasse. The experiment was conducted in a system using two UASB reactors connected in series, followed by an Aerated Submerged Biological Filter (ASBF). The flow rates applied to the system and the corresponded theoretical HRTs in the UASB1, UASB2 and ASBF were respectively: 15.6 L d-1 and 1.2 d, 1.2 d and 1.0 d (Phase I - first year); 8.5 L d-1 and 2.1 d; 2.1 d and 1.8 d (Phase II - first year), 14.6 L d-1 and 1.1 d, 1.1 d and 1.0 d (Phase III - second year); 29.5 L d-1 and 0.6 d, 0.6 d and 0.5 d...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrodynamic study; Tracers; Biological treatment.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542016000600718