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| Registros recuperados: 22 | |
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| Ferreira,Cristiane; Piedade,Maria Teresa Fernandez; Parolin,Pia; Barbosa,Keillah Mara. |
| Himatanthus sucuuba é uma espécie arbórea de reputado valor fitoterápico, que coloniza regiões de várzea e de terra firme na Amazônia Central. Objetivou-se verificar durante quatro meses, em casa de vegetação, a germinação e o desenvolvimento inicial de plântulas da espécie, oriundas de sementes dos dois diferentes ecossistemas. Não houve diferença significativa em relação ao peso de matéria seca de sementes da várzea e da terra firme. Entretanto, a taxa de germinação da espécie variou de acordo com o substrato e o local de procedência das sementes. No substrato areia+serragem (não-alagado) a germinação da espécie foi alta, independente do ambiente (várzea 94% e terra firme 91%). No substrato constituído apenas por água (alagado), as sementes provenientes... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Anoxia; Hipoxia; Dispersão hidrocórica; Estabelecimento de plântulas. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062005000300002 |
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| Silva,Adriane Schio; Laura,Valdemir Antônio; Jank,Liana. |
| The soil flood tolerance of seven genotypes of Panicum maximum Jacq. (PM11, PM34, PM40 and PM45, and the commercial cultivars Massai, Mombaça and Tanzânia) was evaluated in plants subjected to two conditions: flooded and not flooded, during a period of 14 days. Flooding significantly decreased the total and above ground biomass of PM40 and PM45. For cultivar Tanzânia, flooding decreased these two variables and also root biomass. The root, total and above ground relative growth rates were significantly reduced by flooding in cultivar Tanzânia, while in PM45 only the above ground relative growth rate was reduced. Cultivar Tanzânia showed significant differences for all variables analyzed, thus was not flood tolerant, as well as PM40 and PM45. It could be... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Anoxia; Flooding; Forage grass. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000600004 |
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| Oguz,Temel. |
| The Black Sea is a classic anoxic ocean basin resembling the earth's ancient oceanic conditions. Its present structure has evolved during the last 2.5 billion years, and is characterized by a well-defined sub-oxic zone at the interface between the oxic and sulfidic layers where many important bacterially-mediated redox reactions occur. The sub-oxic zone involves extremely low oxygen and sulfide concentrations with no perceptible vertical gradients. This is due to very strong density stratification along the sub-oxic and anoxic layers, which markedly restricts the downward flux of oxygen and upward flux of chemical properties and therefore maintains a stable structure with some inter-annual variations. The upper layer biogeochemical structure above the deep... |
| Tipo: Journal article |
Palavras-chave: Black Sea; Ancient ocean conditions; Sub-oxia; Anoxia; Nitracline. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382006000300012 |
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| Matear,Richard. |
| Global warming projections using a range of climate models included in the IPCC 4th assessment report (AR4) suggest the oceans will warm, the stratification of the upper ocean will increase and the ventilation of the ocean interior will change. These physical changes will impact dissolved oxygen levels in the ocean. Using a global warming projection from the CSIRO (Australian Commonwealth Scientific and Research Administration) climate model linked to a simple ocean biogeochemical model I investigated how dissolved oxygen levels in the ocean interior change under global warming. The climate simulations project the low oxygen regions like the eastern equatorial Pacific will expand. By the end of the century it is projected that the volume of hypoxic water... |
| Tipo: Journal article |
Palavras-chave: Global warming; Oxygen changes; Anoxia; Biogeochemical cycles; Climate change. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382006000300010 |
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| Rabalais,Nancy N. |
| The seasonal formation of a bottom-water layer severely depleted in dissolved oxygen has become a perennial occurrence on the Louisiana continental shelf adjacent to the Mississippi River system. Dramatic changes have occurred in this coastal ecosystem in the last half of the 20th century as the loads of dissolved inorganic nitrogen tripled. There are increases in primary production, shifts in phytoplankton community composition, changes in trophic interactions, and worsening severity of hypoxia. The river-influenced continental shelf is representative of similar ecosystems in which increased nutrient flux to the coastal ocean has resulted in eutrophication and subsequently hypoxia. The hypoxic conditions (dissolved oxygen less than 2 mg L-1) cover up to... |
| Tipo: Journal article |
Palavras-chave: Anoxia; Hypoxia; Eutrophication; Nutrients; Nitrogen. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382006000300015 |
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| Almeida-Val,Vera Maria Fonseca; Oliveira,Alice Reis; Silva,Maria de Nazaré Paula da; Ferreira-Nozawa,Monica Stropa; Araújo,Roziete Mendes; Val,Adalberto Luis; Nozawa,Sérgio Ricardo. |
| Adaptation or acclimation to hypoxia occurs via the modulation of physiologically relevant genes, such as erythropoietin, transferrin, vascular endothelial growth factor, phosphofructokinase and lactate dehydrogenase A. In the present study, we have cloned, sequenced and examined the modulation of the LDH-A gene after an Amazonian fish species, Astronotus crassipinis (the Oscar), was exposed to hypoxia and anoxia. In earlier studies, we have discovered that adults of this species are extremely tolerant to hypoxia and anoxia, while the juveniles are less tolerant. Exposure of juveniles to acute hypoxia and anoxia resulted in increased LDH-A gene expression in skeletal and cardiac muscles. When exposed to graded hypoxia juveniles show decreased LDH-A... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Amazon; Fishes; Gene expression; RT-PCR; LDH-A; Hypoxia; Anoxia. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572011000200025 |
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| Machu, Eric; Capet, Xavier; Estrade, Philippe; Ndoye, S.; Brajard, J.; Baurand, Francois; Auger, P.-a.; Lazar, A.; Brehmer, Patrice. |
| The northeastern Atlantic hosts the most ventilated subsurface waters of any eastern boundary upwelling system, while coastal upwelling source waters are slightly above hypoxic levels. Anoxic conditions have previously been found offshore inside mesoscale eddies whose core waters undergo oxygen consumption for many months. Based on circumstantial in situ observations this study demonstrates that the Senegalese coastal ocean is subjected to episodic occurrence of zero dissolved oxygen concentration at depth along with elevated nitrite concentration (11 mmol/m3) and nitrate/nitrite deficit to phosphate, thereby indicating severe anoxia and intense nitrogen loss. The anoxic event was associated with a prolonged upwelling relaxation episode in March 2012 and a... |
| Tipo: Text |
Palavras-chave: Oxygen; Canary upwelling system; Anoxia; Denitrification; Shallow continental shelf. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00479/59020/61640.pdf |
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| Pakhomova, Svetlana; Yakushev, Evgeniy; Protsenko, Elizaveta; Rigaud, Sylvain; Cossa, Daniel; Knoery, Joel; Couture, Raoul-marie; Radakovitch, Olivier; Yakubov, Shamil; Krzeminska, Dominika; Newton, Alice. |
| This study presents a specifically designed Mercury module in a coupled benthic-pelagic reactive-transport model - Bottom RedOx Model (BROM) that allows to study mercury (Hg) biogeochemistry under different conditions. This module considers the transformation of elemental mercury (Hg(0)), divalent mercury (Hg(II)) and methylmercury (MeHg). The behavior of mercury species in the model is interconnected with changes of oxygen, hydrogen sulfide, iron oxides, organic matter, and biota. We simulated the transformation and transport of Hg species in the water column and upper sediment layer under five different scenarios, combining various levels of oxygenation and trophic state in the Berre lagoon, a shallow eutrophic lagoon of the French Mediterranean coast... |
| Tipo: Text |
Palavras-chave: Mercury; Methylmercury; Biogeochemical modeling; Anoxia; Eutrophication; Lagoon; BROM. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00454/56535/58239.pdf |
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| Souchu, Philippe; Gasc, Anne; Collos, Y; Vaquer, A; Tournier, Henri; Bibent, B; Deslous-paoli, Jean-marc. |
| Physical and chemical characteristics (temperature, salinity, dissolved oxygen), nutrients [dissolved inorganic nitrogen (DIN), soluble reactive phosphorus (SRP) and silicate], dissolved organic nitrogen (DON) and phosphorus and particulate matter [particulate organic carbon (POC) and nitrogen (PON) and chlorophyll a] were measured at a station located in the deepest part of the Thau lagoon (8.5 m), France, during a 10 d period of bottom anoxia in summer 1994. The upper 8 cm of sediment were also analyzed for ammonium (NH(4)(+)) and SRP concentrations in the porewater. The study period was characterized by mean wind speed under 4 m s(-1) which induced an increase of surface temperature from 18 to 29 degrees C with the formation of a thermocline. The... |
| Tipo: Text |
Palavras-chave: Anoxia; Nitrogen; Phosphorus; Eutrophication; Thau lagoon; Mediterranean Sea. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00070/18142/15694.pdf |
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| Menesguen, Alain; Aminot, Alain; Belin, Catherine; Chapelle, Annie; Guillaud, Jean-francois; Joanny, Michel; Lefebvre, Alain; Merceron, Michel; Piriou, Jean-yves; Souchu, Philippe. |
| In order to be able to count the cases of coastal eutrophication and to propose methods to monitor as well as to reduce these phenomena, first of all it is necessary to precisely define the word eutrophication itself. Instead of the strict etymological definition, that is to say a progression of the enrichment of a medium, we will rather retain the concept of a state enriched at a point such as it causes harmful effects on the ecosystem, and nuisances to man's activities. Based on the average chemical equations of the organic matter synthesis/degradation in the sea, this operational definition thus puts forwards the harmful consequences of enrichment, i.e. the production of an excessive algal biomass, sometimes unbalanced from the point of view of... |
| Tipo: Text |
Palavras-chave: Alexandrium; Phaeocystis; Monostroma; Ulva; Dilution plume; Water trapping; Anoxia; Nitrogen and phosphorus loadings; Red tides; Phytoplankton blooms; Green tides; Eutrophication; Alexandrium; Phaeocystis; Monostroma; Ulva; Panache de dilution; Confinement; Anoxie; Phosphate; Nitrate; Apports terrigènes; Eaux colorées; Blooms phytoplanctoniques; Marées vertes; Eutrophisation. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/rapport-22.pdf |
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| Souza,José Gomes de; Beltrão,Napoleão Esberard de Macêdo; Santos,José Wellington dos. |
| O algodoeiro herbáceo (Gossypium hirsutum L. r. latifolium Hutch.) é uma planta considerada sensível à deficiência de oxigênio do solo. O objetivo deste trabalho foi avaliar a fisiologia e produtividade do algodoeiro cultivar CNPA 7H, em casa de vegetação, submetido à anoxia, por encharcamento do solo, na fase de plântula. Foram conduzidos dois experimentos em blocos ao acaso, com sete períodos de encharcamento e seis repetições. No encharcamento de quatro dias ocorreu uma redução na atividade da invertase de 76,69%, da beta-amilase de 77,37% e da redutase do nitrato de 51,10%. A fotossíntese foi afetada a partir do primeiro dia e alcançou decréscimo de 58,63% no décimo quarto dia de encharcamento; os carboidratos foram acumulando-se nas folhas, caule e... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Gossypium hirsutum; Metabolismo; Anoxia; Relação planta-água. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2001000300005 |
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| Carvalho,Cláudio José Reis de; Ishida,Françoise Yoko. |
| O objetivo deste trabalho foi estudar os efeitos do encharcamento do solo sobre a condutância estomática, o conteúdo relativo de água, o teor de clorofila e a concentração de N, P, K e de açúcares solúveis nos tecidos das folhas, bulbos e raízes de pupunheiras (Bactris gasipaes Kunth) jovens. Plantas com seis meses de idade foram submetidas ao alagamento das raízes por períodos contínuos de sete, 14 e 21 dias. O alagamento induziu o fechamento dos estômatos, apesar de os tecidos das folhas terem mantido conteúdos relativos de água em torno de 90%. O alagamento provocou a redução dos teores de clorofila total, N orgânico, P e principalmente K nos tecidos foliares e redução significativa da biomassa das raízes. A anoxia do sistema radicular induziu o acúmulo... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Estômato; Clorofila; Teor de nutrientes; Anoxia. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2002000900005 |
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| Registros recuperados: 22 | |
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