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| Registros recuperados: 18 | |
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| Baisre, J. A.. |
| The alteration of the nitrogen (N) cycle by human activities is widespread and has often resulted in increased flows of nitrogen to the marine environment. In this paper we have attempted to know the changes of N fluxes in Cuba by quantifying the N inputs to the landscape from (1) fertilizer applications, (2) atmospheric deposition, (3) biological nitrogen fixation and (4) net import of food and feeds. N-inputs to the country progressively increased until the end of the 20th century, reaching a peak during the 80s when low cost fertilizer imported from the former Soviet Union led to heavy rates of application. This rapid growth represented more than a 5-fold increase with respect to pristine values; higher than the two-fold global increase of anthropogenic... |
| Tipo: Journal Contribution |
Palavras-chave: Nitrogen; Nitrogen cycle; Atmospheric deposition; Fertilizers. |
| Ano: 2006 |
URL: http://hdl.handle.net/1834/5111 |
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| Civitarese, G; Crise, A; Crispi, G; Mosetti, R. |
| In this work the description of the interaction between the general circulation and the nitrogen cycle in the Ionian Sea is considered. Firstly, an analysis is made of nitrate data collected during POEM-BC cruises in October 1991 and April 1992; then a numerical experiment based on a coupled hydrodynamic ecomodel is presented. The model results relative to the periods corresponding to the cruises are discussed. The ecomodel is climatological and represents an aggregated description of the nitrogen cycle in terms of inorganic nitrogen, phytoplankton and detritus. The numerical results as nitrogen distributions, fluxes and primary production are presented. A strong dependence of nitrogen distribution on circulation emerges both from the observational data... |
| Tipo: Text |
Palavras-chave: Ionian Sea; Nitrogen cycle; General circulation; Ecomodel; Primary production. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00096/20729/18366.pdf |
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| FLÓREZ-ZAPATA,NATHALIA; GARCÍA,JUAN CARLOS; DEL PORTILLO,PATRICIA; RESTREPO,SILVIA; URIBE-VELEZ,DANIEL. |
| In the S. tuberosum group phureja crops, mineral fertilizer and organic amendments are applied to meet the plants´ nutritional demands, however the effect of such practices on the associated rizospheric microbial communities are still unknown. Nitrogen plays an important role in agricultural production, and a great diversity of microorganisms regulates its transformation in the soil, affecting its availability for the plant. The aim of this study was to assess the structure of microbial communities related with the N cycle of S. tuberosum group phureja rizospheric soil samples, with contrasting physical-chemical properties and fertilization strategy. Few significant differences between the community composition at the phylum level were found, only... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nitrogen cycle; Nitrification; Nitrogenase; Pyrosequencing; Solanum phureja. |
| Ano: 2013 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2013000300004 |
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| Fernández-castro, Bieito; Álvarez, Marta; Nieto-cid, Mar; Zunino, Patricia; Mercier, Herle; Álvarez-salgado, Xosé Antón. |
| Dissolved organic matter (DOM) is produced in the surface and exported towards the deep ocean, adding ∼2 PgC yr−1 to the global carbon export. Due to its central role in the Meridional Overturning Circulation (MOC), the eastern subpolar North Atlantic (eSPNA) contributes largely to this export. Here we quantify the transport and budget of dissolved organic nitrogen (DON) in the eSPNA, in a box delimited by the OVIDE 2002 section and the Greenland‐Iceland‐Scotland sills. The MOC exports >15.9 TgN yr−1 of DON downwards and, contrary to the extended view that these are materials of subtropical origin, up to 33% of the vertical flux derives from a net local DON production of 7.1 ± 2.6 TgN yr−1. The low C:N molar ratio of DOM production (7.4 ± 4.1) and the... |
| Tipo: Text |
Palavras-chave: Dissolved organic matter; Nitrogen cycle; Meridional overturning circulation; Subpolar North Atlantic; Metabolic balance. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00485/59622/62649.pdf |
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| Bird, Clare; Lekieffre, Charlotte; Jauffrais, Thierry; Meibom, Anders; Geslin, Emmanuelle; Filipsson, Helena L.; Maire, Olivier; Russell, Ann D.; Fehrenbacher, Jennifer S.. |
| Nitrogen availability often limits biological productivity in marine systems, where inorganic nitrogen, such as ammonium is assimilated into the food web by bacteria and photoautotrophic eukaryotes. Recently, ammonium assimilation was observed in kleptoplast-containing protists of the phylum foraminifera, possibly via the glutamine synthetase/glutamate synthase (GS/GOGAT) assimilation pathway imported with the kleptoplasts. However, it is not known if the ubiquitous and diverse heterotrophic protists have an innate ability for ammonium assimilation. Using stable isotope incubations (15N-ammonium and 13C-bicarbonate) and combining transmission electron microscopy (TEM) with quantitative nanoscale secondary ion mass spectrometry (NanoSIMS) imaging, we... |
| Tipo: Text |
Palavras-chave: Nitrogen cycle; Heterotrophic protists; Foraminifera; Ammonium assimilation; Heterotrophy; Marine. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00662/77421/79087.pdf |
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| PEREIRA, A. M. L.; SILVA, A. E. M. da; OLIVEIRA, C. R. do R.; SILVA, D. A. da; OLIVEIRA, D. W. S; SANTOS, E. P. dos; GONÇALVES JUNIOR, G. F.; KATO, H. C. de A.; ABREU, J. L. de; SILVA, L. O. B. da; PIMENTEL, O. A. L. F.; LIMA, P. C. M. de; OLIVEIRA, V. Q. de; GÁLVEZ, A. O.. |
| Introdução. Ciclo do nitrogênio na carcinicultura. Microrganismos responsáveis pela oxidação e transformação dos compostos nitrogenados. Estratégias de fertilização com carbono orgânico para o controle dos compostos nitrogenados no cultivo de camarão marinho. Estratégias de utilização do carbono inorgânico para auxiliar o controle dos compostos nitrogenados no cultivo de camarão marinho. Qualidade de água e sua importância para ajudar no controle dos compostos nitrogenados. Fertilização mineral em sistemas de baixa salinidade e sua influência sobre os compostos nitrogenados. Considerações finais. Referências. |
| Tipo: Livros |
Palavras-chave: Camarão marinho; BRS Aqua; Aquicultura; Cadeia Produtiva; Ciclo do Nitrogênio; Viveiro; Carcinicultura; Qualidade da Água; Aquaculture; Nitrogen cycle; Food chain; Nursery management; Shrimp; Nitrogen compounds; Litopenaeus vannamei; Water quality. |
| Ano: 2022 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/1144229 |
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| Morita, R; Jones, R. |
| The nitrifying bacteria were found to survive 24 weeks in the absence of ammonium without decreasing their number of cell size. Because H sub(2), CO, and CH sub(4) are present in the marine environment, these substrates were investigated as a possible source of the energy of maintenance for the nitrifying bacteria. super(14)CO and super(14)CH sub(4) were found to be oxidized by the nitrifiers. N-serve was found to inhibit the oxidation of CO. Using the nitrifiers' ability to oxide CO, a method for the determination of the nitrification rate was developed. The ability of nitrifiers to oxidize CO may play a significant role in the cycling of CO sub(2) in the marine environment. Whether CO and CH sub(4) oxidation play a role in the survival of nitrifiers in... |
| Tipo: Text |
Palavras-chave: Methane; Carbon dioxide; Survival; Bacteria; Nitrification; Nitrogen cycle; Oxidation; Carbon cycle; Biogeochemistry; Metabolism. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-975.pdf |
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| Ulloa,Osvaldo; Belmar,Lucy; Farías,Laura; Castro-González,Maribel; Galán,Alexander; Lavín,Paris; Molina,Verónica; Ramírez,Salvador; Santibáñez,Francisco; Stevens,Heike. |
| In recent years, our group has been studying the microbial communities of the water column associated with the oxygen minimum zone (OMZ) off northern Chile and Peru, trying to understand who the main players are in the OMZ biogeochemical cycles and which metabolic strategies they are using. For that, we are combining flow cytometry, molecular techniques and biogeochemical approaches. Most of our work, so far, has focused on microbes capable of doing oxygenic photosynthesis, such as the cyanobacteria, and those involved in the nitrogen cycle, such as the denitrifying, nitrifying and anammox bacteria. We have also started to look at the more general microbial abundance and diversity. In each case, we are finding that the OMZ holds distinct microbial... |
| Tipo: Journal article |
Palavras-chave: Oxygen minimum zone; Microbial diversity; Nitrogen cycle. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382006000300018 |
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| Plus, Martin; Chapelle, Annie; Menesguen, Alain; Deslous-paoli, Jean-marc; Auby, Isabelle. |
| A numerical deterministic model for a seagrass ecosystem (Zostera noltii meadows) has been developed for the Thau lagoon. It involves both above- and belowground seagrass biomasses, nitrogen quotas and epiphytes. Driving variables are light intensity, wind speed, rain data and water temperature. This seagrass model has been coupled to another biological model in order to simulate the relative contributions of each primary producer to: (i) the total ecosystem production, (ii) the impact on inorganic nitrogen and (iii) the fluxes towards the detritus compartment. As a first step in the modelling of seagrass beds in the Thau lagoon, the model has a vertical structure based on four boxes (a water box on top of, three sediment boxes) and the horizontal... |
| Tipo: Text |
Palavras-chave: Thau lagoon; Nitrogen cycle; Oxygen cycle; Box model; Seagrass ecosystem. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/2003/publication-461.pdf |
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| Herbert, R. |
| Seasonal data and depth profiles using super(15)N-labelled NO sub(3)u- show that denitrification (77-90% of NO sub(3)u- respired) rather than NO sub(3)u- dissimilation to NH sub(4)u+ was the principal route of nitrate reduction in Kingoodie Bay sediments. Populations of both groups of NO sub(3)u- reducing bacteria were highest in the 0-20 mm horizon in those sediments where highest rates of NO sub(3)u- respiration were recorded (28.56 mu g N.d super(-1) dry wt. sediment super(-1)). Autotrophic nitrification rates shared a marked seasonality with highest rates (0.92 mu g N.d super(-1).g dry wt. sediment super(-1)) occurring during the summer. Maximum populations of autotrophic nitrifying bacteria were also found in the 0-20 mm sediment horizon and these... |
| Tipo: Text |
Palavras-chave: Seasonal variations; Bacteria; Estuaries; Sediment chemistry; Biogeochemistry; Ammonia; Nitrates; Nitrogen cycle. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-971.pdf |
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| Иванов, В. А.; Любарцева, С. П.; Михайлова, Э. Н.; Шапиро, Н. Б.. |
| Обсуждается наш опыт моделирования экосистемы Черного моря. Трехкомпонентная модель экосистемы (планктон, биоген, детрит) объединяется с трехмерной гидротермодинамической моделью для исследования причинно-следственных связей между вынуждающими физическими силами и биогеохимической изменчивостью в приустьевой зоне Дуная. С учетом механизма физического переноса, фотосинтеза, смертности планктона, оседания и реминерализации детрита решаются уравнения типа адвекция-диффузия-реакция. Чтобы изучить влияние метеорологических условий на состояние экосистемы, было проведено три численных эксперимента: при отсутствии ветра и слабом (5 м/с) северо-восточном и северо-западном ветре. Была разработана объединенная трехмерная крупномасштабная модель Черного моря,... |
| Tipo: Journal Contribution |
Palavras-chave: Экосистема; Трехмерное численное моделирование; Верхний квазиоднородный слой; Азотный цикл; Приустьевая зона Дуная; Черное море; Ecosystem; 3D numerical modeling; Upper mixed layer; Nitrogen cycle; Danube’s mouth zone; The Black Sea Nitrogen cycle Ecosystems Nitrogen cycle Ecosystems http://aims.fao.org/aos/agrovoc/c_27938 http://aims.fao.org/aos/agrovoc/c_2482. |
| Ano: 2003 |
URL: http://repository.ibss.org.ua/dspace/handle/99011/167 |
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| Registros recuperados: 18 | |
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