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| Registros recuperados: 95 | |
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| MORAES, S. da S.. |
| Deficiências e desequilíbrios minerais em bovinos são descritas em quase todas as regiões do mundo. Os elementos minerais comumente deficientes para bovinos com dieta exclusiva de pasto são: P, Na, I, Cu, Co, e Se. Em algumas regiões sob condições especificas, Ca, Mg e Mn. Por outro lado, Fe e Mn estão, normalmente, em excesso nas regiões do Cerrado Central do Brasil e Pantanal. A ingestão de dietas deficientes ou desequilibradas de elementos minerais torna mais difícil a manutenção de concentrações ótimas nos tecidos . No inicio, causa lesões bioquímicas que induzem a trocas nas formas de funcionamento, concentração e atividade do elemento nos fluidos e tecidos do corpo. Essas alterações diferem conforme os elementos e suas funções, com o grau de duração... |
| Tipo: Documentos (INFOTECA-E) |
Palavras-chave: Bovino de corte; Brasil; Mineral deficiencies; Sulphur; Yodine.; Cálcio; Cloro; Cobre; Cobalto; Deficiência Mineral; Ferro; Enxofre; Fósforo; Manganês; Magnésio; Iodo; Potássio; Selênio; Sódio; Zinco.; Calcium; Cobalt; Copper; Brazil; Beef cattle; Chlorine; Iron; Magnesium; Manganese; Phosphorus; Potassium; Sodium; Selenium; Zinc.. |
| Ano: 2001 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/325198 |
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| Guegueniat, P; Boust, D; Gandon, R; Hemon, G; Phillipot, J; Sanchez, J; Marin, P; Pieri, J. |
| This paper reports the study of iron geochemical behavior by the measurement of total iron, iron associated with mineral coat, and ratio FEII/FEIII. The results of total iron are exploited by normalisation with regard to aluminium and scandium. |
| Tipo: Text |
Palavras-chave: River discharge; Sediments; Suspended particulate matter; Ion association; Iron; Geochemical cycle. |
| Ano: 1985 |
URL: http://archimer.ifremer.fr/doc/1985/acte-1301.pdf |
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| Henley, Sian F.; Cavan, Emma L.; Fawcett, Sarah E.; Kerr, Rodrigo; Monteiro, Thiago; Sherrell, Robert M.; Bowie, Andrew R.; Boyd, Philip W.; Barnes, David K. A.; Schloss, Irene R.; Marshall, Tanya; Flynn, Raquel; Smith, Shantelle. |
| The Southern Ocean plays a critical role in regulating global climate as a major sink for atmospheric carbon dioxide (CO2), and in global ocean biogeochemistry by supplying nutrients to the global thermocline, thereby influencing global primary production and carbon export. Biogeochemical processes within the Southern Ocean regulate regional primary production and biological carbon uptake, primarily through iron supply, and support ecosystem functioning over a range of spatial and temporal scales. Here, we assimilate existing knowledge and present new data to examine the biogeochemical cycles of iron, carbon and major nutrients, their key drivers and their responses to, and roles in, contemporary climate and environmental change. Projected increases in... |
| Tipo: Text |
Palavras-chave: Southern Ocean; Biogeochemistry; Primary production; Iron; Nutrients; Carbon; Ecosystem; Ocean acidification. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00676/78831/81113.pdf |
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| Laes, Agathe; Vuillemin, Renaud; Leilde, Bernard; Sarthou, Géraldine; Bournot Marec, Claudie; Blain, Stéphane. |
| A sensitive method for iron determination in seawater has been adapted on a submersible chemical analyser for in situ measurements. The technique is based on flow injection analysis (FIA) coupled with spectrophotometric detection. When direct injection of seawater was used, the detection limit was 1.6 nM, and the precision 7%, for a triplicate injection of a 4 nM standard. At low iron concentrations, on line preconcentration using a column filled with 8-hydroxyquinoline (8HQ) resin was used. The detection limit was 0.15 nM (time of preconcentration = 240 s), and the precision 6%, for a triplicate determination of a I nM standard, allowing the determination of Fe in most of the oceanic regimes, except the most depleted surface waters. The effect of... |
| Tipo: Text |
Palavras-chave: Temperature and pressure effects; Submersible chemical analyser; Seawater; In situ measurements; Iron; Flow injection analysis. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-1209.pdf |
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| Zbinden, M; Shillito, B; Le Bris, Nadine; De Montlaur, C; Roussel, Erwan; Guyot, F; Gaill, F; Cambon-bonavita, Marie-anne. |
| The Rimicaris exoculata dominates the megafauna of some of the Mid Atlantic ridge hydrothermal vent sites. This species harbors a rich community of bacterial epibionts inside its gill chamber. Literature data indicate that a single 16S rRNA phylotype dominates this epibiotic community, and is assumed to be a sulfide-oxidizing bacteria. However attempts Of Cultivation were not successful and did not allow to confirm it. The aim of our study was to test the hypothesis of sulfide oxidation in the gill chamber, by a multidisciplinary approach, using in vivo experiments at in situ pressure in the presence of sulfide, microscopic observations and a molecular survey. Morphology of microorganisms, before and after treatment, was analyzed to test the effect of... |
| Tipo: Text |
Palavras-chave: Sulfur; Methane; Iron; Intracellular granules; Hydrothermal vent shrimp; High pressure experiments. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4563.pdf |
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| Koedooder, Coco; Gueneugues, Audrey; Van Geersdaele, Remy; Verge, Valerie; Bouget, Francois-yves; Labreuche, Yannick; Obernosterer, Ingrid; Blain, Stephane. |
| Iron (Fe) is an essential element for marine microbial growth but is present in trace amounts (<0.1 nM) in surface waters of the ocean. In heterotrophic bacteria, Fe-limitation particularly impacts ATP production as Fe is an essential co-factor of enzymes involved in the electron-transport chain as well as the tricarboxylic acid (TCA) cycle. Fe-limitation can therefore drastically reduce both bacterial growth and respiration, consequently affecting the efficiency of organic carbon remineralization. Heterotrophic bacteria possess various strategies to cope with Fe-limitation. In the present study we tested the hypothesis that the induction of the glyoxylate shunt can represent one such strategy. Genetic approaches were used to gain insight into the... |
| Tipo: Text |
Palavras-chave: Iron; Fe-limitation; Photobacterium angustum S14; Glyoxylate shunt; Isocitrate lyase. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00468/58017/60413.pdf |
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| Whitby, Hannah; Bressac, Matthieu; Sarthou, Geraldine; Ellwood, Michael J.; Guieu, Cécile; Boyd, Philip W.. |
| Iron is a key micronutrient in seawater, but concentrations would be negligible without the presence of organic ligands. The processes influencing the ligand pool composition are poorly constrained, limiting our understanding of the controls on dissolved iron distributions. To address this, the release of iron and iron‐binding ligands during the microbial remineralisation of sinking particles was investigated by deploying in situ particle interceptor/incubator devices at subsurface sites in the Mediterranean Sea and Subantarctic. Analyses revealed the pool of released ligands was largely dominated by electroactive humic substances (74 ± 28%). The release of ligands during remineralisation ensured that concurrently released iron remained in solution, which... |
| Tipo: Text |
Palavras-chave: Iron; Ligand; Humic; Remineralisation; Particle; Degradation. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00618/72981/72055.pdf |
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| Vong, Lilita; Laes, Agathe; Blain, Stéphane. |
| A new method for the non-specific determination of iron-porphyrin-like complexes in natural waters has been developed. It is based on the chemiluminescent oxidation of the luminol in the presence of dioxygen (O-2) at pH 13. The method has been implemented in a FIA manifold that allowed the direct injection of seawater. The limit of detection is 0.11 nM of equivalent hemin (Fe-protoporphyrin IX). Fe2+, Fe3+, H2O2, siderophore (deferoxamin mesylate), humic acid and phytic acid did not interfere when the), were present at the concentrations expected in seawater. Metal free porphyrin and Mg, Cu, Co porphyrin complexes did not induce a significant chemiluminescent signal. Poisoned unfiltered samples could be stored for several weeks before analyses. The new... |
| Tipo: Text |
Palavras-chave: Chemiluminescence; Complexation; Flow injection; Seawater; Porphyrin; Iron. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3298.pdf |
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| González-santana, David; Planquette, Helene; Cheize, Marie; Whitby, Hannah; Gourain, Arthur; Holmes, Thomas; Guyader, Vivien; Cathalot, Cecile; Pelleter, Ewan; Fouquet, Yves; Sarthou, Geraldine. |
| Hydrothermal vents are a recognized source of trace elements to the ocean inventory. Nevertheless, the contribution of slow-spreading ridges remains poorly resolved. To address this, high-resolution dissolved (<0.45 μm) iron (dFe) and manganese (dMn) samples were collected during the GEOTRACES HERMINE GApr07 process study at the Mid Atlantic Ridge. Samples were collected at nine stations, from the TAG vent site to 75 km south-southwest following the neutrally buoyant plume. Concentrations of dMn and dFe ranged from 71 ± 6 and 51 ± 2 nmol kg–1 right above the vent site to 0.43 ± 0.01 and 1.56 ± 0.02 nmol kg–1 at the most distal station, respectively. Using a 5-box model coupled with our data, we show that as the plume traveled away from the vent,... |
| Tipo: Text |
Palavras-chave: Iron; Manganese; Hydrothermal; TAG; Mid Atlantic Ridge; GEOTRACES. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75530/76431.pdf |
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| Pasquer, B; Laruelle, G; Becquevort, S; Schoemann, V; Goosse, H; Lancelot, C. |
| We present results obtained with SWAMCO-4, a complex model of the marine planktonic system calculating C, N, P, Si, Fe cycling within the upper ocean, the export production and the exchange of CO2 between the ocean and atmosphere. The model, constrained by physical, chemical and biological (grazing, lysis) controls, explicitly details the dynamics of four relevant phytoplankton functional groups with respect to C, N, P, Si, Fe cycling and climate change. Those are diatoms, pico/nano phytoplankton, coccolithophorids, and Phaeocystis spp. whose growth regulation by light, temperature and nutrients has been obtained based on a comprehensive analysis of literature reviews on these taxonomic groups. The performance of SWAMCO-4 is first evaluated in a 1D... |
| Tipo: Text |
Palavras-chave: Ecological modelling; Diatoms; Pico/nanophytoplankton; Coccolithophorids; Phaeocystis spp.; Iron; Air-sea CO2 fluxes; Global ocean; Antarctic ocean; North Atlantic. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00232/34302/32677.pdf |
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| Moppert, Xavier; Le Costaouec, Tinaig; Raguenes, Gerard; Courtois, Anthony; Simon-colin, Christelle; Crassous, Philippe; Costa, Bernard; Guezennec, Jean. |
| A bacterium isolated from microbial mats located on a polynesian atoll produced a high molecular weight (3,000 kDa) and highly sulphated exopolysaccharide. Previous studies showed that the chemical structure of this EPS consisted of neutral sugars, uronic acids, and high proportions of acetate and sulphate groups. The copper- and iron-binding ability of the purified pre-treated native EPS was investigated. Results showed that this EPS had a very high affinity for both copper (9.84 mmol g(-1) EPS) and ferrous iron (6.9 mmol g(-1) EPS). Amazingly, this EPS did not show any affinity for either ferric ions or selenium salts. This finding is one of the first steps in assessing the biotechnological potential of this polysaccharide. |
| Tipo: Text |
Palavras-chave: Sulphated exopolysaccharide; Microbial mats; Iron; Copper; Binding capacity. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6397.pdf |
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| Cheize, Marie; Planquette, H.f.; Fitzsimmons, J.n.; Pelleter, Ewan; Sherrell, R.m.; Lambert, Christophe; Bucciarelli, E.; Sarthou, G.; Le Goff, Marion; Liorzou, Celine; Chéron, Sandrine; Viollier, E.; Gayet, Nicolas. |
| A number of trace metals play essential roles in marine ecosystem structure and biological productivity. Until recently, it has been argued that phytoplankton access primarily dissolved iron, while particulate iron was considered a refractory material with little use biologically and limited interaction with the dissolved pool. In order to assess the transfer mechanisms between sediment-sourced particulate trace metals and the dissolved pool, we conducted a 14-month incubation that reacted resuspended sediments with natural seawater, both originating from the Kerguelen area (KEOPS cruises; Southern Ocean), in the dark, and at concentrations replicating natural conditions. Three types of sediments were investigated (named BioSi, BioSi + Ca, and Basalt),... |
| Tipo: Text |
Palavras-chave: Suspended particle dissolution; Sediment; Iron; Manganese; Biogenic silica; Southern Ocean; Kerguelen. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00460/57197/59166.pdf |
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| Stolte, Willem; Balode, Maija; Carlsson, Per; Grzebyk, Daniel; Janson, Sven; Lips, Inga; Panosso, Renata; Ward, Clive J.; Graneli, Edna. |
| In the Baltic Sea, floating blooms of nitrogen-fixing cyanobacteria occur yearly during late summer. These blooms can sometimes be limited by iron. Due to extensive foresting around the Baltic Sea, iron is entering the Baltic Sea partly bound to dissolved organic material (DOM) via rivers. An experiment was performed in 300 1 laboratory mesocosms to test the hypothesis that riverine high-molecular weight dissolved organic matter (HMWDOM), extracted by tangential flow filtration > 1000 Da, stimulates the biomass of nitrogen-fixing cyanobacteria, by increasing the availability of iron. The addition of iron/EDTA and of DOM resulted in 5 to 10 times higher biomass of nitrogen-fixing cyanobacteria. Accordingly, higher primary production and particulate... |
| Tipo: Text |
Palavras-chave: Mesocosm experiment; Humic acid; HMWDOM; High molecular weight dissolved organic matter; Iron; Nitrogen fixation; Cyanobacteria. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2470.pdf |
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| Louropoulou, Evangelia; Gledhill, Martha; Browningi, Thomas J.; Desai, Dhwani K.; Barraqueta, Jan-lukas Menzel; Tonnard, Manon; Sarthou, Geraldine; Planquette, Helene; Bowie, Andrew R.; Schmitz, Ruth A.; Laroche, Julie; Achterberg, Eric P.. |
| Heme b is an iron-containing co-factor in hemoproteins. Heme b concentrations are low (< 1 pmol L-1) in iron limited phytoplankton in cultures and in the field. Here, we determined heme b in marine particulate material (> 0.7 mu m) from the North Atlantic Ocean (GEOVIDE cruise - GEOTRACES section GA01), which spanned several biogeochemical regimes. We examined the relationship between heme b abundance and the microbial community composition, and its utility for mapping iron limited phytoplankton. Heme b concentrations ranged from 0.16 to 5.1 pmol L-1 (median = 2.0 pmol L-1, n = 62) in the surface mixed layer (SML) along the cruise track, driven mainly by variability in biomass. However, in the Irminger Basin, the lowest heme b levels (SML: median =... |
| Tipo: Text |
Palavras-chave: Heme b; North Atlantic; Phytoplankton; Diatoms; Iron; Limitation; GEOTRACES; GEOVIDE. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00508/61940/66029.pdf |
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| Tagliabue, Alessandro; Barrier, Nicolas; Du Pontavice, Hubert; Kwiatkowski, Lester; Aumont, Olivier; Bopp, Laurent; Cheung, William W. L.; Gascuel, Didier; Maury, Olivier. |
| Earth System Models project that global climate change will reduce ocean net primary production (NPP), upper trophic level biota biomass and potential fisheries catches in the future, especially in the eastern equatorial Pacific. However, projections from Earth System Models are undermined by poorly constrained assumptions regarding the biological cycling of iron, which is the main limiting resource for NPP over large parts of the ocean. In this study, we show that the climate change trends in NPP and the biomass of upper trophic levels are strongly affected by modifying assumptions associated with phytoplankton iron uptake. Using a suite of model experiments, we find 21st century climate change impacts on regional NPP range from −12.3% to +2.4% under a... |
| Tipo: Text |
Palavras-chave: Climate change; Iron; Marine ecosystems; Net primary production; Ocean. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00652/76417/77470.pdf |
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| Toner, Brandy M.; Rouxel, Olivier; Santelli, Cara M.; Bach, Wolfgang; Edwards, Katrina J.. |
| Hydrothermal sulfide chimneys located along the global system of oceanic spreading centers are habitats for microbial life during active venting. Hydrothermally extinct, or inactive, sulfide deposits also host microbial communities at globally distributed sites. The main goal of this study is to describe Fe transformation pathways, through precipitation and oxidation-reduction (redox) reactions, and examine transformation products for signatures of biological activity using Fe mineralogy and stable isotope approaches. The study includes active and inactive sulfides from the East Pacific Rise 9 degrees 50'N vent field. First, the mineralogy of Fe(III)-bearing precipitates is investigated using microprobe X-ray absorption spectroscopy (RXAS) and X-ray... |
| Tipo: Text |
Palavras-chave: Hydrothermal; East Pacific Rise; X-ray absorption spectroscopy; Stable isotopes; Micro-environment; Mineral alteration; Iron; Biosignature. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00337/44810/44375.pdf |
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| Registros recuperados: 95 | |
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