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Registros recuperados: 11
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A room temperature procedure for the manual determination of urea in seawater OMA
Goeyens, L.; Kindermans, N.; Yusuf, M.A.; Elskens, M..
Several earlier studies underpin the important role of dissolved organic matter and more particularly urea in phytoplanktonic nitrogen uptake fluxes. Generally, the determination of urea concentrations relies on the formation of an imidazolone-thiosemicarbizide complex, a complexation which requires very accurate temperature control when carried out at high temperature. It is also possible, however, to obtain reliable results with a room temperature procedure. The measured abundances for both complexation at high temperature (85 degree C, 20 min) and at ambient temperature (22 degree C, 72 h) are closely comparable. Lower values are observed for temperatures <10 degree C though. Moreover, a comparison of both techniques reveals similar precision...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Dissolved organic carbon; Sea water; Temperature; Urea; Water analysis.
Ano: 1998 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=7858
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Carbono orgânico dissolvido na precipitação, solução de solo, água freática, e água fluvial nas microbacias dos igarapés São João e Cumaru sob diferentes usos da terra. Repositório Alice
FELIZZOLA, J. F.; CREÃO, L. G. C.; PACHECO, N. A.; FIGUEIREDO, R. de O.; CRUZ, F.; LIMA, M. de O.; CARNEIRO, B..
2015
Tipo: Resumo em anais de congresso (ALICE) Palavras-chave: Carbono orgânico; Água; Igarapé; Uso do solo; Uso da terra; Qualidade da água; Water quality; Dissolved organic carbon.
Ano: 2015 URL: http://www.alice.cnptia.embrapa.br/handle/doc/1030510
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Dissolved Organic Carbon Determination Using FIA and Photo-Fenton Reaction BABT
Kondo,Márcia M.; Arcos,Maria A. S. V.; Grassi,Marco T..
The FIA-photo-Fenton system is based on the flow oxidation of the organic matter. A small amount of the sample containing H2O2 is injected into the acidic flow solution of Fe2+, which passes through a tubular PTFE reactor irradiated with UV light. The generated CO2 is quantified by a conductometric detector and is directly proportional to the dissolved organic carbon concentration in the sample. The optimization studies were performed using EDTA solutions. The average recovery of organic carbon was 83% with a relative standard deviation of 3.7% using a 1:5 molar ratio of Fe2+:H2O2, pH 2.0, 100 muL of sample injection and a liquid flow of 1 mL min-1. After optimization, the DOC concentration was quantified using 13 different organic compounds, where the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Photo-Fenton reaction; Dissolved organic carbon; FIA.
Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000100013
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Dissolved organic carbon, nitrogen and phosphorus in the N-E Atlantic and the N-W Mediterranean with particular reference to non-refractory fractions and degradation ArchiMer
Aminot, Alain; Kerouel, Roger.
Dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP) measured in deep profiles in the N-E Atlantic and in the N-W Mediterranean in the period 1984-2002 are described. After accurate validation, they show close agreement with those previously published. Classic profiles were obtained, with concentrations decreasing in deep waters. In the Mediterranean and in the Atlantic comparable concentrations were found in the 1500-2000 m waters, 44-46 mumol 1(-1) DOC, 2.6-2.8 mumol 1(-1) DON and 0.02-0.03 mumol 1-1 DOP. In the surface layers, DOC concentrations were higher, but DON and DOP concentrations lower, in the Mediterranean than in the Atlantic, leading to higher element ratios in the Mediterranean. In autumn,...
Tipo: Text Palavras-chave: N W Mediterranean; N E Atlantic; Mineralization; Non refractory; Refractory; Dissolved organic phosphorus; Dissolved organic nitrogen; Dissolved organic carbon.
Ano: 2004 URL: http://archimer.ifremer.fr/doc/2004/publication-472.pdf
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Fishes of the Amazon: diversity and beyond Anais da ABC (AABC)
VAL,ADALBERTO LUIS.
Abstract: The Amazon basin houses a particular group of freshwater organisms, whose study tells the geological history of the region, how biological diversity was shaped, how it is maintained, and what it hides. The fish of the Amazon is represented by more than 3,000 known species distributed from the basal groups up to the more specialized ones. This species richness hides a diversity of adaptations that are dispersed at all levels of the biological organization. In this summary of the conference delivered at the Brazil-France Bilateral Symposium, held in Manaus in 2018, we describe two aspects of the hidden world of adaptive diversity: adaptations to changes in dissolved oxygen and the abilities of the Rio Negro fish to face acidic and ion-poor waters...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Amazonia; Biodiversity; Adaptations; Hypoxia; Dissolved organic carbon; Climate changes.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652019000600602
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Gypsum application, soil fertility and cotton root growth Bragantia
Pivetta,Laércio Augusto; Castoldi,Gustavo; Pivetta,Laerte Gustavo; Maia,Suelen Cristina Mendonça; Rosolem,Ciro Antonio.
ABSTRACT Since there is no consensus on phosphogypsum (PG) rates to be used in agriculture, a better understanding of its effects on the soil solution is needed. Cotton root growth was evaluated as related to Al and Ca activity in soil solution affected by PG. The experiment was carried out in rhizotrons filled with30∙dm–3 of soil. PG rates were estimated by multiplying the soil clay content by 0.0, 1.5, 3.0, 6.0 and 12.0, and it was mixed to the sub-soil.In the upper soil layer, limestone was applied. After 90 days, samples were taken for analysis, and cotton was planted. After27 days, plants were harvested. PG increased soil pH and decreased Al content and activity. Without PG, dissolved organic carbon concentration was high in the soil solution, which...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Aluminum; Dissolved organic carbon; Soil chemistry.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052019000200264
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Kinetics of the aerobic decomposition of Talauma ovata and Saccharum officinarum - doi: 10.4025/actascibiolsci.v34i4.9396 Biological Sciences
Gimenes, Karen Zauner; Universidade Federal de São Carlos; Leite-Rossi, Luciene Aparecida; Universidade Federal de São Carlos; Cunha-Santino, Marcela Bianchessi; Universidade Federal de São Carlos; Bianchini Junior, Irineu; Universidade Federal de São Carlos; Trivinho-Strixino, Susana; Universidade Federal de São Carlos.
The aim of this study is to evaluate the kinetics of aerobic decomposition of Saccharum officinarum and Talauma ovata leaves. For each species, decomposition chambers (leaves and water) were set up, which were maintained under controlled conditions. Each sampling day (1, 7, 15, 30, 39, 58, 72 and 90 days), the concentrations of total organic carbon, pH and electrical conductivity (EC) were determined in the dissolved fraction, while the mass and cell wall fractions (CWF) were determined in the particulate fraction. The pH stabilization of the chambers with T. ovata and S. officinarum leaves occurred in alkaline (ca. 8 - 8.5) and close to the neutrality (ca. 7 - 7.5) environment, respectively. The EC values were on average 1.6 times higher in incubations...
Palavras-chave: 2.05.00.00-9 riparian zone; Mass loss; Mineralization; Dissolved organic carbon; Particulate organic carbon 2.05.00.00-9.
Ano: 2012 URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/9396
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Liming and Ionic speciation of an Oxisol under no-till system Scientia Agricola
Zambrosi,Fernando Cesar Bachiega; Alleoni,Luís Reynaldo Ferracciú; Caires,Eduardo Fávero.
The chemical speciation of the soil solution is an important tool for evaluating nutrient availability and aluminum phytotoxicity. The effect of liming in the composition of the soil solution under the no-till (NT) system is still not well known. We evaluated the chemical speciation of Al and nutrients in the soil solution (water extract 1:1), five years after liming at the moment of the establishment of NT in a native pasture, in Ponta Grossa, Paraná State, Brazil. Dolomitic lime was applied at a rate of 4.5 t ha-1 (either incorporated or surface-applied), or split in three annual rates of 1.5 t ha-1. Soil samples from a dystrophic clayey Rhodic Hapludox were collected at the 0 - 0.05; 0.05 - 0.1; 0.1 - 0.2; 0.2 - 0.4; 0.4 - 0.6; and 0.6 - 0.8 m layers,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Dolomitic lime; Complex; Ionic pair; Dissolved organic carbon.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162008000200013
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Molecular changes of aquatic humic substances formed from four aquatic macrophytes decomposed under different oxygen conditions. Repositório Alice
ASSUNÇÃO, A. W. A.; SOUZA, B. P; SILVA, W. T. L. da; CUNHA-SANTINO, M. B.; BIANCHINI JR, I..
bitstream/item/169456/1/P-Molecular-changes-of-aquatic....pdf
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: E4/E6; Dissolved organic carbon; Dissolved oxygen; Fulvic acid; FTIR; Humic acid.
Ano: 2017 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1083130
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Processes that influence dissolved organic matter in the soil: a review Scientia Agricola
Gmach,Maria Regina; Cherubin,Maurício Roberto; Kaiser,Klaus; Cerri,Carlos Eduardo Pellegrino.
ABSTRACT: In tropical regions, climate conditions favor fast decomposition of soil organic matter (SOM), releasing into the soil organic composts in solid, liquid, and gaseous forms with variable compositions. Dissolved organic matter (DOM), a complex mixture of thousands of organic compounds, is only a small fraction of the decomposition products; however, it is highly mobile and reactive to the soil. Therefore, DOM play a key role in soil aggregation (formation of organometallic complexes), energy source for microorganisms, as well as C storage, cycling, and provision of plant-available nutrients. DOM multifunctionality to sustain soil functions and important ecosystem services have raised global scientific interest in studies on DOM fractions. However,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Brazil; Dissolved organic carbon; Agricultural soils; Tropical soils.
Ano: 2020 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162020000301800
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Sorção e lixiviação de tiametoxam em solos tratados com lodo de esgoto e cultivados com cafeeiro. Repositório Alice
MAGALHAES, C. A. de S.; LIMA, J. M. de; COSTA, A. L. da; SILVA, E. G. da; SILVA, C. A.; BETTIOL, W.; NOBREGA, J. C. A.; GUIMARES, P. T. G..
Abastract: The objective of this study was to evaluate the sorption and leaching of thiamethoxam in dystrophic Red-Yellow Latosol (LVAd), dystroferric Red Latosol (LVdf) and Red-Yellow Argisol (PVAd) with coffee under the effect of sewage sludge doses. There was thiamethoxam sorption decreasing at higher doses of sewage sludge in LVAd and LVdf. In the PVAd, sorption was higher in samples that received the highest dose of sewage sludge. At 150 days after the application of thiamethoxam, the compound began to be detected in the effluent, in all soils. Dissolved organic carbon had no influence on the thiamethoxam leaching.
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Adubo de esgoto; Inseticida; Lixiviação; Sorção; Matéria orgânica; Biosolids; Sewage sludge; Soil pollution; Dissolved organic carbon; Insecticides; Sorption; Leaching.
Ano: 2012 URL: http://www.alice.cnptia.embrapa.br/handle/doc/943415
Registros recuperados: 11
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