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| Registros recuperados: 68 | |
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| Barrales Brito, Edgar. |
| El mantillo y horizontes de fermentación (CF) es un reservorio dinámico de carbono (C) en suelos forestales. Las metodologías que cuantifican la emisión de CO2 por la descomposición son escasas y requieren periodos largos de medición. Se requieren métodos para poder generar información de la emisión de CO2 de éstas capas orgánicas en tiempos cortos de medición. Los objetivos fueron: generar un protocolo para la medición de la emisión de CO2 por la descomposición de mantillo y CF con un respirómetro manométrico (OxiTop ®). Medir los reservorios de C de mantillo y CF de bosques con diferentes condiciones. Medir la emisión de CO2 del mantillo y CF y las tasas de descomposición con un respirómetro. Analizar las características químicas de los mantillos y... |
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Palavras-chave: Biogeoquímica; Emisión de CO2; Respirometría; Materia orgánica; Bosques; Biogeochemistry; CO2 emissions; Respirometry; Organic matter; Forest; Edafología; Maestría. |
| Ano: 2013 |
URL: http://hdl.handle.net/10521/2096 |
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| PARRON, L. M.; BUSTAMANTE, M. M. da C.; PRADO, C. L. C.. |
| RESUMO: Em função do gradiente de umidade na topografia do terreno e de diferenças entre estações seca e chuvosa, o presente trabalho teve como objetivos quantificar a produção anual e a disponibilidade de nutrientes (N, P, K, Ca, Mg E S) na serapilheira e estimar a eficiência do uso de nutrientes em uma Mata de Galeria. O experimento foi estabelecido numa área de 100 x 100 m da Mata de Galeria do Córrego Pitoco, na Reserva Ecológica do IBGE, DF (15°56'41"S e 47°56'07"W). Como delineamento experimental, foram estabelecidas três linhas de amostragem paralelas ao córrego, distantes 45 m entre si, denominadas, respectivamente, comunidades úmida (na margem do córrego), intermediárias e seca (adjacentes a uma área de Cerrado Típico). A produção de serapilheira... |
| Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E) |
Palavras-chave: Biogeoquímica; Ciclagem de nutriente; Eficiência de nutriente; Savana; Productivity; Nutrient cycling; Litterfall; Nutrient efficiency.; Disponibilidade de Nutriente; Floresta Tropical; Produtividade.; Biogeochemistry; Tropical forests.; Savannas. |
| Ano: 2004 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/569203 |
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| Conway, T. M.; John, S. G.; Lacan, F.. |
| Intercomparison of trace metal data is a key aspect of the International GEOTRACES program, allowing data from multiple laboratories and countries to be combined to produce high-resolution datasets for the oceans. The use of crossover stations by the GEOTRACES program provides the opportunity both for comparison of analytical techniques and assessment of temporal variability in the cycling of trace metals such as iron (Fe). Here, we present the first comparison of dissolved Fe stable isotope ratio (δ56Fe; relative to IRMM-014) profiles in the oceans, from re-occupations of three locations in the Atlantic Ocean; (1) the Bermuda Atlantic Time Series Station (31.75°N 64.17°W) during the U.S. GEOTRACES IC1 cruise (June 2008) and the U.S. GEOTRACES GA03 cruise... |
| Tipo: Text |
Palavras-chave: Trace metals; GEOTRACES; Biogeochemistry; Intercomparison. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00332/44330/43932.pdf |
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| Rousseau, Tristan C. C.; Sonke, Jeroen E.; Chmeleff, Jerome; Van Beek, Pieter; Souhaut, Marc; Boaventura, Geraldo; Seyler, Patrick; Jeandel, Catherine. |
| Rare earth element (REE) concentrations and neodymium isotopic composition (epsilon Nd) are tracers for ocean circulation and biogeochemistry. Although models suggest that REE release from lithogenic sediment in river discharge may dominate all other REE inputs to the oceans, the occurrence, mechanisms and magnitude of such a source are still debated. Here we present the first simultaneous observations of dissolved (< 0.45 mu m), colloidal and particulate REE and eNd in the Amazon estuary. A sharp drop in dissolved REE in the low-salinity zone is driven by coagulation of colloidal matter. At mid-salinities, total dissolved REE levels slightly increase, while epsilon Nd values are shifted from the dissolved Nd river endmember (- 8.9) to values typical of... |
| Tipo: Text |
Palavras-chave: Earth sciences; Biogeochemistry; Oceanography. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00298/40952/40046.pdf |
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| Koliyavu, Timoci; Martias, Chloe; Singh, Awnesh; Mounier, Stéphane; Gérard, Philippe; Dupouy, Cecile. |
| Heavy rain events alter the biogeochemical outflows, affects water quality and ecosystem health within the coastal waters of small Pacific Islands. We characterized snapshots of the optical fingerprints of dissolved organic matter (DOM) sources together with the select nutrients, biogeochemical and physical variables for 10 stations in December 2017 in Laucala Bay, Fiji Islands. DOM absorption coefficients and fluorescence components were determined via spectrofluorometry and Parallel Factor Analysis identifying four components: Type M, two terrestrial (humic, fulvic) components, and a protein component linked to marine biological activity. Associations of DOM together with climate variables and the other tested variables were determined via principal... |
| Tipo: Text |
Palavras-chave: DOM absorption; Fluorescence; Biogeochemistry; PARAFAC; EEM spectra; Autochthonous; Allochthonous; Chlorophyll; CDOM; FDOM. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79372/81889.pdf |
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| Rondeau, B; Cossa, Daniel; Gagnon, P; Pham, T; Surette, C. |
| Surface water samples from the St. Lawrence River were collected in order to study the processes controlling minor and trace elements concentrations (Al, Fe, Mn, Cd, Co, Cu, Ni and Zn), and to construct mass balances allowing estimates of the relative importance of their natural and anthropogenic sources. The two major water inputs, the upper St. Lawrence River, which drains waters originating from the Lake Ontario, and the Ottawa River were collected fortnightly over 18 months. In addition, other tributaries were sampled during the spring floods. The output was monitored near Quebec City at the river mouth weekly between 1995 and 1999. Dissolved metal concentrations in the upper St. Lawrence River carbonated waters were lower than in the acidic waters of... |
| Tipo: Text |
Palavras-chave: St. Lawrence; Mass balance; River; Biogeochemistry; Trace element. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-1357.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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| Pagès, Rémi; Baklouti, Melika; Barrier, Nicolas; Ayache, Mohamed; Sevault, Florence; Somot, Samuel; Moutin, Thierry. |
| The Mediterranean region has been shown to be particularly exposed to climate change, with observed trends that are more pronounced than the global tendency. In forecast studies based on a RCP 8.5 scenario, there seems to be a consensus that, along with an increase in temperature and salinity over the next century, a reduction in the intensity of deep-water formation and a shallowing of the mixed layer [especially in the North-Western Mediterranean Sea (MS)] are expected. By contrast, only a few studies have investigated the effects of climate change on the biogeochemistry of the MS using a 3D physical/biogeochemical model. In this study, our aim was to explore the impact of the variations in hydrodynamic forcing induced by climate change on the... |
| Tipo: Text |
Palavras-chave: Mediterranean Sea; Coupled hydrodynamic-biogeochemical model; RCP scenario; Biogeochemistry; Climate change. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00659/77073/78385.pdf |
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| Alvarez, M.; Tanhua, T.; Brix, H.; Lo Monaco, C.; Metzl, N.; Mcdonagh, E. L.; Bryden, H. L.. |
| Within the Subantarctic Mode Water (SAMW) density level, we study temporal changes in salinity, nutrients, oxygen and TTD (Transit Time Distribution) ages in the western (W) and eastern (E) subtropical gyre of the Indian Ocean (IO) from 1987 to 2002. Additionally, changes in Total Alkalinity (TA) and Dissolved Inorganic Carbon (DIC) are evaluated between 1995 and 2002. The mechanisms behind the detected changes are discussed along with the results from a hindcast model run (Community Climate System Model). The increasing salinity and decreasing oxygen trends from 1960 to 1987 reversed from 1987 to 2002 along the gyre. In the W-IO a decreasing trend in TTD ages points to a faster delivery of SAMW, thus less biogenic matter remineralization, explaining the... |
| Tipo: Text |
Palavras-chave: Indian Ocean; Subantarctic Mode Water; Biogeochemistry. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00253/36400/34942.pdf |
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| Swaney, D. P.; Humborg, C.; Emeis, K.; Kannen, A.; Silvert, W.; Tett, P.; Pastres, R.; Solidoro, C.; Yamamuro, M.; Henocque, Yves; Nicholls, R.. |
| Social and ecological systems around the world are becoming increasingly globalized. From the standpoint of understanding coastal ecosystem behavior, system boundaries are not sufficient to define causes of change. A flutter in the stock market in Tokyo or Hong Kong can affect salmon producers in Norway or farmers in Togo. The globalization of opportunistic species and the disempowerment of people trying to manage their own affairs on a local scale seem to coincide with the globalization of trade. Human-accelerated environmental change, including climate change, can exacerbate this sense of disenfranchisement. The structure and functioning of coastal ecosystems have been developed over thousands of years subject to environmental forces and constraints... |
| Tipo: Text |
Palavras-chave: Scale; Coastal management; Governance; Fishery management; Regime shift; Biogeochemistry. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00073/18437/16086.pdf |
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| Hermin, M; Daumas, R; Drogue, N. |
| The bacterial activity of the superficial sediment layer was evaluated by incorporation super(14)C-labelled amino-acids mixed an hydrolysate of chlorella cells. Estimation of super(14)C-CO sub(2) super(14)C and super(14)C-A.A. by H.P.L.C. give some informations on the utilization of free dissolved. A.A. and on the transport of labelled compounds from water to sediment. The adsorption mechanism of A.A. on the mineral particles draw to the sediment a larger part of A.A. in the first period; but 28% of this adsorbed A.A. were discharged by an acid treatment. A part of super(14)C-A.A. was incorporated in unhydrolysable organic matter. Di-COOH A.A. are more resistant to bacterial degradation than the other A.A., but arginine is completely metabolized in ten... |
| Tipo: Text |
Palavras-chave: Biogeochemistry; Bacteria; Chromatographic techniques; Metabolism; Amino acids; Sediment water exchanges. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-945.pdf |
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| Bertoni, R. |
| The radiochemical methods proposed for evaluating heterotrophic activity in waters have been severely criticized in recent years because they are not considered to be sufficiently realistic. Thus, the possibility of directly measuring the heterotrophic consumption of naturally occurring Organic Carbon (OC) in fresh water samples incubated under controlled conditions has been evaluated. The analytical performances of two OC analyzers utilizable for this purpose are discussed here, and some examples of the results obtained by the direct measurement of OC consumption are presented. The consumption rates thus measured ranged from 11.6 to 50.2 mu gC/ 1.h. Although the technique discussed here is less sensitive than radiochemical methods, the few assumptions... |
| Tipo: Text |
Palavras-chave: Biogeochemistry; Microbiology; Carbon cycle; Organic carbon; Water; Heterotrophic organisms; Analytical techniques. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-950.pdf |
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| Registros recuperados: 68 | |
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