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| Registros recuperados: 108 | |
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| MEIRELLES, M. L.; FRANCO, A. C.; FERREIRA, E. A. B.; RANDOW, C. V.. |
| O objetivo deste estudo foi relacionar a altura do lençol freático com os fluxos diurnos de CO2 em um campo limpo úmido (Brasília, DF). Foram monitorados a altura da lâmina do lençol freático; a assimilação de CO2 pelo processo fotossintético de duas gramíneas que representavam 50% da cobertura vegetal; a quantificação do fluxo de CO2 do solo por um equipamento acoplado a câmara de solo; e os fluxos de CO2 atmosférico pelo método micrometeorológico de covariância de vórtices turbulentos. A lâmina de água em 2005 atingiu profundidade de 80 cm e, em 2006, esteve próxima à superfície durante todo o ano, cujas variações não exerceram um efeito na capacidade fotossintética de Axonopus comans, entretanto foram medidos valores menores em Andropogon virgatus,... |
| Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E) |
Palavras-chave: Área úmida; Luminosidade; Wetland; Savanna.; Carbono; Cerrado; Fotossíntese; Lençol Freático; Solo.; Carbon; Groundwater; Photosynthesis; Soil.. |
| Ano: 2010 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/894343 |
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| OLIVEIRA, L. O. F. de; FERNANDES, A. H. B. M.; FERNANDES, F. A.; SANTOS, S. A.; CRISPIM, S. M. A.; GARCIA, J. B.; SANTOS, R. dos. |
| A principal atividade econômica do Pantanal é a pecuária bovina de corte, a qual vem convivendo harmoniosamente no ambiente há mais de 200 anos (ABREU et al., 2008), reciclando nutrientes e gerando renda à sua população. No entanto, os processos fermentativos ocorridos no rúmen dos bovinos com a finalidade de degradação da fibra (celulose e hemicelulose, principalmente), além da geração de energia e outros nutrientes utilizados no metabolismo animal, produzem também, de acordo com as dietas, menor ou maior quantidade do gás metano (CH4), havendo necessidade do conhecimento deste volume de emissão. Além de outras medidas necessárias para os avanços nos estudos sobre o ciclo do C na pecuária pantaneira, as estimativas de emissão de metano constituem papel... |
| Tipo: Documentos (INFOTECA-E) |
Palavras-chave: Produção animal; Pecuária; Manejo; Carbono; Biogás; Metano.; Carbon; Methane.. |
| Ano: 2015 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/1036802 |
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| Landschuetzer, Peter; Ilyina, Tatiana; Lovenduski, Nicole S.. |
| We use a neural network-based estimate of the sea surface partial pressure of CO2 (pCO(2)) derived from measurements assembled within the Surface Ocean CO2 Atlas to investigate the dominant modes of pCO(2) variability from 1982 through 2015. Our analysis shows that detrended and deseasonalized sea surface pCO(2) varies substantially by region and the respective frequencies match those from the major modes of climate variability (Atlantic Multidecadal Oscillation, Pacific Decadal Oscillation, multivariate ENSO index, Southern Annular Mode), suggesting a climate modulated air-sea exchange of CO2. We find that most of the regional pCO(2) variability is driven by changes in the ocean circulation and/or changes in biology, whereas the North Atlantic variability... |
| Tipo: Text |
Palavras-chave: Ocean; CO2; Variability; Carbon; Climate; Observations. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00675/78733/80972.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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| Leonard, Noemie. |
| Recirculation of the water of fish rearing systems requires a biological treatment based on the nitrifying activity of autotrophic bacteria. In parallel heterotrophic bacterial populations utilise the organic substrate, produced by the fish, to grow. Opposite to the autotrophic populations, the heterotrophic bacteria (1) have a quick growth and (2) might contain fish pathogenic strains. The main aim was to characterise the heterotrophic bacteria populations ?.nd to understand (1) which parameters do control the dynamics of their populations and (2) their influence on the quality of the recirculating water. In a rearing system, the heterotrophic bacterial populations are stable in number and in genus, for a given operating mode. The bacteria are either... |
| Tipo: Text |
Palavras-chave: Carbon; Gills; Bacterium; Humics substances; Fish; Ozone; Aquiculture; Carbone; Branchies; Bacterie; Substances humiques; Poisson; Ozone; Aquaculture. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/these-1728.pdf |
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| Majkut, Joseph D.; Sarmiento, J. L.; Rodgers, K. B.. |
| Concerted community efforts have been devoted to producing an authoritative climatology of air-sea CO2 fluxes, but identifying decadal trends in CO2 fluxes has proven to be more challenging. The available surface pCO(2) estimates are too sparse to separate long-term trends from decadal and seasonal variability using simple linear models. We introduce Markov Chain Monte Carlo sampling as a novel technique for estimating the historical pCO(2) at the ocean surface. The result is a plausible history of surface pCO(2) based on available measurements and variability inferred from model simulations. Applying the method to a modern database of pCO(2) data, we find that two thirds of the ocean surface is trending toward increasing uptake of CO2, with a mean (year... |
| Tipo: Text |
Palavras-chave: Carbon; Assimilation; LDEO2010; Trend. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40156/38724.pdf |
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| Le Quere, Corinne; Takahashi, Taro; Buitenhuis, Erik T.; Roedenbeck, Christian; Sutherland, Stewart C.. |
| About one quarter of the CO2 emitted to the atmosphere by human activities is absorbed annually by the ocean. All the processes that influence the oceanic uptake of CO2 are controlled by climate. Hence changes in climate (both natural and human-induced) are expected to alter the uptake of CO2 by the ocean. However, available information that constrains the direction, magnitude, or rapidity of the response of ocean CO2 to changes in climate is limited. We present an analysis of oceanic CO2 trends for 1981 to 2007 from data and a model. Our analysis suggests that the global ocean responded to recent changes in climate by outgassing some preindustrial carbon, in part compensating the oceanic uptake of anthropogenic CO2. Using a model, we estimate that climate... |
| Tipo: Text |
Palavras-chave: Ocean; Carbon; CO2 sink. |
| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00253/36412/34957.pdf |
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| Zheng, Li-wei; Hsiao, Silver Sung-yun; Ding, Xiao-dong; Li, Dawei; Chang, Yuan-pin; Kao, Shuh-ji. |
| Total organic carbon to total nitrogen ratios (C/N) and their isotopic compositions (δ13CTOC and δ15NTN) are oft-applied proxies to discern terrigenous from marine-sourced organics and to unravel ancient environmental information. In high depositional Asian marginal seas, the inclusion of N-bearing minerals in the bulk sediment dilutes or masks signals sought after in δ15N and δ13C analyses, thus leading to incorrect and even contradictory interpretations. We used KOH-KOBr to separate operationally defined total organic matter into oxidizable (labile) and residual fractions for content and isotope measurements. In a sediment core in the Okinawa Trough, significant amounts of carbon and nitrogen existed in the residual phase, in which the C/N ratio was ~9,... |
| Tipo: Text |
Palavras-chave: Carbon; Nitrogen; Isotope; Okinawa Trough; Sediment; Total organic carbon. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00295/40584/39503.pdf |
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| Guazzelli Gonzalez, Julio; Ménard, Frédéric; Le Loc'H, François; Agrelli De Andrade, Humber; Pontes Viana, Andréa; Ferreira, Valdimere; Frédou, Flávia Lucena; Lira, Alex Souza; Munaron, Jean-marie; Frédou, Thierry. |
| We investigated the trophic niches and the resource partitioning of two snook species, the common (Centropomus undecimalis) and the fat snook (C. parallelus), in four tropical estuaries of the northeastern Brazil, using stable isotope analyses of carbon (δ13C) and nitrogen (δ15N). Fish specimens, mainly juveniles, basal resources and a primary consumer were collected in 2015 during dry and rainy seasons in all estuaries, which exhibited differences in system size, geomorphologic shapes, levels of sea access and anthropic pressures. Potential effect of factors like fish body length, estuary and seasonality on isotope ratios were investigated. Positive relationships between the size of fish and δ15N values were found, regardless the species. Our results... |
| Tipo: Text |
Palavras-chave: Brackish water fish; Trophic relationships; Carbon; Nitrogen; Centropomus. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00506/61767/65745.pdf |
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| Gomez, E; Millet, B; Picot, B. |
| The Mejean-Perols Lagoon is situated on the French Mediterranean coast. It is a small (747 ha) and shallow (70 cm) lagoon. Some treated effluent from Montpellier flows into this hypereutrophic lagoon. The cartography of C, N and P concentrations in the sediment was studied based on 35 bottom samples. The nitrogen and organic carbon concentrations were more or less homogeneous, the highest concentrations being found in the middle of the lagoon. The phosphate was principally bound onto the sediment in the west zone. The observed distribution was independent of grain size, the distribution of which was rather homogeneous. In this lagoon water circulation is wind induced. Four different water flow structures were observed, as functions of the prevailing winds... |
| Tipo: Text |
Palavras-chave: Sédiment; Lagune côtière; Hydrodynamique; Sels nutritifs; Carbone; Sediment; Coastal lagoon; Hydrodynamics; Nutrients; Carbon. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00325/43642/43247.pdf |
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| Registros recuperados: 108 | |
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