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Assessment of nitrogen flows into the Cuban landscape OceanDocs
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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Ciclagem de nitrogênio em florestas tropicais e plantações de eucalipto no Brasil no Antropoceno. Repositório Alice
SILVA, J. J. N. da; MELLO, W. Z. de; RODRIGUES, R. de A. R.; ALVES, B. J. R.; SOUZA, P. A. de; CONCEIÇÃO, M. C. G. da.
O nitrogênio é um macronutriente essencial para o funcionamento do metabolismo dos seres vivos. Porém, devido às mudanças que o planeta vem passando no Antropoceno a ciclagem do nitrogênio vem sendo alterada. O desmatamento aliado às mudanças do uso do solo são os principais responsáveis pela alteração da sua ciclagem. As emissões de gases de efeito estufa como do N2O foram aumentadas em virtude desse desmatamento e das inadequadas práticas de manejo do solo, e isso acabou contribuindo para que essas mudanças na ciclagem do nitrogênio ocorressem. Visto a importância do nitrogênio e das alterações que ele vem passando nas últimas décadas, este trabalho de revisão tem como objetivo descrever o papel do nitrogênio e as alterações na sua ciclagem devido aos...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Ciclo do Nitrogênio; Floresta Tropical; Eucalipto; Nitrogen cycle; Tropical forests; Eucalyptus.
Ano: 2018 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1101569
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Ciclo do nitrogênio em sistemas agrícolas. Repositório Alice
VIEIRA, R. F..
O ciclo biogeoquímico do nitrogênio apresenta um conjunto diverso de transformações que envolve a ocorrência deste elemento no solo, no ar e na água e que são, na maioria das vezes, realizadas pelos microrganismos. Muitos destes organismos são especializados na condução de processos específicos. De forma geral, as transformações do N desencadeiam uma ampla rede de reações de oxidação-redução, a partir das quais os microrganismos obtêm energia para algum tipo de atividade relativa ao seu metabolismo. Embora a maior parte das etapas envolvidas no ciclo do N tenha sido identificada há mais de um século, ainda hoje nos deparamos com novas descobertas. Os primeiros 10 anos do século XXI foram extremamente importantes no entendimento das relações funcionais...
Tipo: Livro científico (ALICE) Palavras-chave: Fixação biológica do nitrogênio; Fixação simbiótica do nitrogênio; Ciclo do nitrogênio; Agricultura; Nitrificação; Desnitrificação; Nitrogen cycle; Agriculture.
Ano: 2017 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1090589
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Circulation effects on nitrogen dynamics in the Ionian Sea ArchiMer
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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COMPOSITION AND FUNCTION OF THE MICROBIAL COMMUNITY RELATED WITH THE NITROGEN CYCLING ON THE POTATO RHIZOSPHERE Acta biol.Colomb.
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: Journal 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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Cycle de la matière et variabilité environnementale en élevage larvaire de Litopenaeus stylirostris en Nouvelle-Calédonie ArchiMer
Millot, Anne-sophie.
Since 2005, shrimp livestock of Litopenaeus stylirostris in New Caledonia has dealed with production issues. One of them concerns the lack of postlarvae following high mortality rates in hatcheries. This study aims the evolution of the environmental quality status in three rearing from nauplius to postlarvae stage. Among nutrients, total ammonia nitrogen (TAN), soluble reactive phosphorus (SRP), nitrates and nitrites (NOx) have been quantified. Organic matter was also estimated through dissolved organic nitrogen (DON), urea nitrogen and colored dissolved organic matter (CDOM). Finally, bacteria were followed through bacterial abundance and respiration. The hatchery cycle can be divided in two stages: the first one in which antibiotics were delivered to...
Tipo: Text Palavras-chave: Écloserie de crevette; Milieu d’élevage; Cycle de l’azote; Compartiment bactérien; Gestion des déchets; Shrimp hatchery; Rearing environment; Nitrogen cycle; Bacterial compartment; Waste management.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00472/58368/60928.pdf
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Dissolved organic nitrogen production and export by meridional overturning in the eastern subpolar North Atlantic ArchiMer
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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Metabolism of CO and CH sub(4) by nitrifiers and the determination of the nitrification rate. ArchiMer
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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Metabolism of cyanobacteria in anaerobic marine sediments. ArchiMer
Stal, L; Krumbein, W.
Two cyanobacteria isolated from marine microbial mats metabolized endogenous carbon reserves anaerobically in the dark. Microcoleus chthonoplastes reduced elemental sulfur to sulfide and Oscillatoria sp. additionally produced lactate in the absence of elemental sulfur. Under nitrogen fixing conditions, however, no sulfur reduction occurs. Lactate fermentation appeared to be the mechanism of anaerobic carbon degradation under these conditions. With a nitrogenase-reducible substrate, e.g. acetylene, added, lactate fermentation as well as sulfur reduction stops in cultures of Oscillatoria containing nitrogenase. In this case only ethylene production was observed. These cyanobacteria seem to possess the capability to carry out anaerobic dark metabolism...
Tipo: Text Palavras-chave: Oscillatoria; Microcoleus chthonoplastes; Cyanophyta; Metabolism; Chemical cycles; Algae; Anoxic sediments; Anaerobic respiration; Algal mats; Biogeochemistry; Fermentation; Sulfur; Nitrogen fixation; Nitrogen cycle.
Ano: 1984 URL: http://archimer.ifremer.fr/doc/1984/acte-974.pdf
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Microbial communities and their biogeochemical role in the water column of the oxygen minimum zone in the eastern South Pacific Gayana
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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Modelling seasonal dynamics of biomasses and nitrogen contents in a seagrass meadow (Zostera noltii Hornem.): application to the Thau lagoon (French Mediterranean coast) ArchiMer
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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Monitoramento temporal dos teores de nitrogênio de solo de floresta nativa e floresta queimada no leste do Estado do Acre. Repositório Alice
OLIVEIRA, R. V. M. de; COSTA, F. de S.; SILVA, L. S. da.
A dinâmica temporal do nitrogênio (N) no solo é mediada por microrganismos e dependentes da precipitação pluviométrica e temperaturas do ar atmosférico e do solo. A precipitação pluviométrica influencia a umidade do solo, que regula reações de redução-oxidação do N, especialmente em solo denso ou compactado devido à mudança de seu uso de floresta nativa para outros usos.
Tipo: Resumo em anais de congresso (ALICE) Palavras-chave: Embrapa Acre; Rio Branco (AC); Acre; Amazônia Ocidental; Western Amazon; Amazonia Occidental; Ciclo do nitrogênio; Nitrato de amônio; Argissolos; Floresta nativa; Operação florestal; Queimada; Nitrogen cycle; Ammonium nitrate; Clay soils; Primary forests; Burnt soils; Ciclo del nitrógeno; Nitrato de amonio; Suelos arcillosos; Bosques primarios; Suelos quemados.
Ano: 2018 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1089899
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Nitrate respiration and nitrification in estuarine sediments. ArchiMer
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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NON-SYMBIOTIC NITROGEN FIXATION, NET NITROGEN MINERALIZATION AND DENITRIFICATION IN EVERGREEN FORESTS OF CHILOÉ ISLAND, CHILE: A COMPARISON WITH OTHER TEMPERATE FORESTS Gayana Botánica
Pérez,C.A.; Carmona,M.R.; Armesto,J.J..
Temperate forests in southern Chile offer unique opportunities for studying biogeochemical cycles in the absence of industrial air pollution. Here we compare three important fluxes of the nitrogen (N) cycle in temperate forests of southern Chile, non-symbiotic N fixation, net N mineralization and denitrification, with data from northern temperate forests more affected by air pollution. We studied five evergreen, old-growth forests and one second-growth forest in Chiloé Island, southern Chile. Non-symbiotic N fixation in the litter layer, mineral soil and coarse woody debris was estimated by the acetylene reduction technique. In situ net-N mineralization in the upper mineral soil layer was assessed by the buried bag method. Denitrification rates of mineral...
Tipo: Journal article Palavras-chave: Denitrification; Nitrogen cycle; Nitrogen fixation; Temperate forests; Unpolluted forests.
Ano: 2003 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432003000100005
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Reduction du nitrate dans les sediments marins. Comparaison des activites mesurees in vitro et in situ ArchiMer
Esteves, J; Bonin, P; Blanc, F; Mille, G; Bertrand, J.
In vitro nitrate reduction in hydrocarbon-polluted marine sediments has been studied by flow-through system. By analysing the rate of nitrate comsumption as a function of nitrate concentration the authors determined the Michaelis-Menten kinetics parameters. (km = 330 mu M; vax = 2.0 mu M/g super(-1)/h super(-1). The authors found a value of 60 mu M/m super(-2)/h super(-1) for the rate of in vitro nitrate consumption derived from the above kinetic parameters and from the nitrate concentration in the sediment. In parallel a value of 67.4 mu M/m super(-2)/h super(-1) was found for the rate of nitrate consumption under in situ conditions. The great similarity between both results would favor the in vitro technique as a valid and more convenient one.
Tipo: Text Palavras-chave: MED; Biogeochemistry; Oil pollution; Methodology; Environmental conditions; Experimental research; Comparative studies; Metabolism; Bacteria; Sediment chemistry; Reduction; Nitrates; Denitrification; Nitrogen cycle.
Ano: 1984 URL: http://archimer.ifremer.fr/doc/1984/acte-979.pdf
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Transfert et mineralisation de la matiere organique azotee a travers les deux premiers echelons de la micro communaute heterotrophe ArchiMer
Vanwambeke, F; Bianchi, M.
Bacterial response to organic (amino acids) or inorganic (NH sub(4) super(+)) nitrogen was studied in 350 liter closed batch systems. The experiments demonstrate an important NH sub(4) super(+) remineralization associated with bacterial growth. The differences between substrate and bacterial C/N ratios and bacterial metabolic demands partly explain the high values of ammonia produced. Grazing by heterotrophic microflagellates resulted in an important release of NH sub(4) super(+). This suggests and important role of grazers for the nitrogen remineralization in natural waters.
Tipo: Text Palavras-chave: Flagellata; Ciliata; Bacteria; Plankton; Heterotrophic organisms; Ammonia; Amino acids; Nitrogen cycle; Mineralization.
Ano: 1984 URL: http://archimer.ifremer.fr/doc/1984/acte-986.pdf
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Моделирование возникновения и распространения гипоксии на мелководье IBSS Repository
Васечкина, Е. Ф.; Ярин, В. Д..
Имитируется ситуация развития гипоксии в период весенне-летнего прогрева на мелководье. Исследуется пространственно-временная динамика процесса. Используется объектно-ориентированная модель планктонного сообщества пелагиали, дополненная гидрохимическим блоком, который описывает циклы азота и серы в аэробных и анаэробных условиях. Гидродинамика системы описывается интегральной двухслойной моделью, учитывающей влияние атмосферной изменчивости на развитие процесса. Моделируется реакция живых компонентов системы на смену режима в нижнем слое с окислительного на восстановительный и обратно.
Tipo: Journal Contribution Palavras-chave: Гипоксия; Цикл азота и серы; Аэробно-анаэробные условия; Пространственная неоднородность планктона; Объектно-ориентированное моделирование; Hypoxia; Nitrogen cycle; Sulfur cycle; Aerobic and anaerobic conditions; Spatial; Object-oriented modeling Spatial variations Nitrogen cycle Hypoxia Nitrogen cycle Hypoxia http://aims.fao.org/aos/agrovoc/c_27938 http://aims.fao.org/aos/agrovoc/c_24472.
Ano: 2006 URL: http://repository.ibss.org.ua/dspace/handle/99011/294
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Современные междисциплинарные модели экосистемы Черного моря IBSS Repository
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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