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| Registros recuperados: 369 | |
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| KARRASCH,BERNHARD; WOELFL,STEFAN; URRUTIA,ROBERTO; GONZÁLEZ,JENNY; VALDOVINOS,CLAUDIO; CID,HERNÁN; PARRA,OSCAR. |
| A strong socio-economic development pressure in South Chile will more and more cause an impact to the present lakes and rivers. Nevertheless, our knowledge concerning the ecological structure and the microbial self-purification capabilities of these lacustrine water bodies is scant but essential for a future sustainable development of land and water use. We studied Lake Laja, a lake already heavily impacted by water diversions for hydropower generation and irrigation. Typical for the Andean region Lake Laja is an oligotrophic water body, limited by nitrogen nutrients. Only very low chlorophyll a and particulate organic carbon (POC) concentrations and a small abundance and biomass of bacteria (mainly ultramicrobacteria) and heterotrophic flagellates were... |
| Tipo: Journal article |
Palavras-chave: Bacterioplankton extracellular enzymes heterotrophic flagellates N-limitation; Phytoplankton. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2011000300010 |
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| Nival, Paul; Malara, G.. |
| Choosing the best conditions for the cultivation of plankton in tanks is a difficult deal, which is generally solved by means of subjective estimations. A better way of looking for these conditions is the use of a mathematical model. _ We have tried to built a model that accounts for the physical and biological characteristics of the tanks. The data concerning the physiological characteristics of the different group of organisms encountered are too scarce to allow all of them to be taken into account. The system studied here is composed of nutrients, phytoplankton, herbivorous copepods and rotifers to which benthic algae have been added. With the hypothesis of 3 elements (phyto - zooplankton - nutrients) it can be showed that when an equilibrium is... |
| Tipo: Text |
Palavras-chave: Phytoplancton; Zooplancton; Culture; Modèle mathématique; Phytoplankton; Zooplankton; Culture; Mathematical model. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00306/41673/40882.pdf |
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| Hernando, M.P.. |
| The increments in the ultraviolet radiation B (RUVB, 280-320 nm) resultants of the destruction of the ozone layer affect diverse echo-physiologic aspects of the marine phytoplankton. On this study were compared the responses of phytoplankton from an ambient Sub-Antarctic (Channel Beagle, 54º 52´S, 68º 18´W) and another Antarctic (Potter Cove, 62º 14´S, 58º 38´W) to the ultraviolet radiation (RUV). The decrease of the photosynthesis on short term (hours) was observed in both places, however inhibition thresholds were present. In the Beagle Channel, these were for RUVB and ultraviolet radiation A (RUVA, 320-400 nm), respectively, 0,2 and 6,2 Wm-2 for communities with more than 70% diatoms and 0,45 and 14,2 Wm-2, respectively, for communities with more than... |
| Tipo: Theses and Dissertations |
Palavras-chave: Phytoplankton; Photosynthesis; Ultraviolet radiation; Vertical mixing; Taxonomy; Phytoplankton; Taxonomy; Photosynthesis; Ultraviolet radiation; Http://aims.fao.org/aos/agrovoc/c_13344; Http://aims.fao.org/aos/agrovoc/c_7631; Http://aims.fao.org/aos/agrovoc/c_5812; Http://aims.fao.org/aos/agrovoc/c_8046. |
| Ano: 2008 |
URL: http://hdl.handle.net/1834/2868 |
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| Guesdon, Stephane; Stachowski-haberkorn, Sabine; Lambert, Christophe; Beker, Beatriz; Brach-papa, Christophe; Auger, Dominique; Bechemin, Christian. |
| This study aimed to describe seasonal variations of phytoplankton abundances in relation to the physical and chemical (nutrients and metals) environment under the influence of freshwater input in the Charente river estuary (Marennes-Oléron bay, France) over three years, from 2011 to 2014. Phytoplankton abundances were determined using microscopy and flow cytometry. Considering high frequency temperature and salinity data, breakpoints in each series led to the identification of two local hydroclimatic periods: the first (2011 and early 2012) being warmer and higher in salinity than the second (from spring 2012 to the beginning of 2014). A multiblock PLS analysis highlighted the significant contribution of the physical environment (temperature, salinity and... |
| Tipo: Text |
Palavras-chave: Hydroclimate; Estuary; Phytoplankton; Size composition; Nutrients; Trace metals. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00349/46005/45674.pdf |
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| Labry, Claire; Delmas, Daniel; Moriceau, Brivaela; Gallinari, Morgane; Quere, Julien; Youenou, Agnes. |
| Phosphorus (P) limitation of phytoplankton growth is known to affect the accumulation and release of carbohydrates (CHO) by micro-algae. However, relatively little is known about the fate of algal exudates, notably their bacterial degradation. The CHO chemical characterization is also not exhaustive, especially in ‘functional’ pools relevant for phytoplankton physiology (particulate reserve [R] or structural [S] CHO) and for bacterial degradation (dissolved mono- [MDCHO] and polysaccharides [P-DCHO]). In this study, we investigated how P depletion and repletion affect the CHO composition in diatom Thalassiosira weissflogii cultures, and the shortterm response of free and diatom-attached bacteria in terms of abundance and potential βglucosidase activity... |
| Tipo: Text |
Palavras-chave: P limitation; Phytoplankton; Diatom; Bacteria; Mineralization; Carbohydrate; Glucosidase. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00628/74045/73532.pdf |
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| Tyrrell, T.; Merico, A.; Waniek, J. J.; Wong, C. S.; Metzl, N.; Whitney, F.. |
| We calculated correlations between seafloor depth and phytoplankton blooms in all three main high-nitrate, low-chlorophyll (HNLC) regions, but with a particular focus on the subarctic North Pacific area. It has long been known that the central parts of the east and west subarctic North Pacific are HNLC regions. The deep western basin of the Bering Sea is also HNLC, whereas the wide continental shelf of the eastern Bering Sea is not. We carried out a statistical comparison of spatial maps of (1) seafloor depth and (2) chlorophyll a concentration from satellite data. This comparison reveals that shallow waters have, on average, higher peak chlorophyll a concentrations (more intense phytoplankton blooms) than deep waters (p << 0.01). Possible artifacts... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Ocean color; Bathymetry; HNLC; North Pacific; Iron. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00232/34337/32758.pdf |
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| Goutx, H; Berland, B; Leveau, M; Bertrand, J. |
| The effects of products resulting from petroleum biodegradation in continuous culture, have been studied on the growth of two marine algae. Sugars, lipids and amino acids are the main components resulting from petroleum degradation in the bacteria used medium. Their concentrations are respectively 600 mg.l super(-1), 46 mg.l super(-1) and 74.2 mu M.l super(-1). The algae growth is inhibited when products are enough concentrated; it is stimulated by low concentration. Among these products, lipids are more toxic than others. The two species show different sensitivity towards the used medium. Prorocentrum micans growth is more inhibited than that of Phaeodactylum tricornutum . |
| Tipo: Text |
Palavras-chave: Bacteria; Phytoplankton; Toxicity; Oil pollution; Crude oil; Biodegradation. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-1017.pdf |
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| Ben Othman, H.; Meddeb, M.; Hadj Mabrouk, H.; Hlaili, S.. |
| La lagune de Bizerte devient un récepteur privilégié des micropolluants dont certains sont toxiques et peuvent constituer une menace pour l’équilibre de cet écosystème. Parmi ces polluants, les hydrocarbures aromatiques polycycliques (HAP) sont retenus comme des polluants prioritaires. La présente étude est une première investigation de l’effet d’un HAP, le Benzo(a)pyrène [B(a)py], sur la communauté phytoplanctonique au niveau d’une station lagunaire (station plus ou mois polluée par le B(a)py) et une station au niveau du canal (station la plus polluée par le B(a)py) en été (juillet) et automne (novembre) 2009. Pour cela, des communautés phytoplanctoniques, collectées des deux stations, ont été maintenues en culture pendant 6 jours sous trois différents... |
| Tipo: Journal Contribution |
Palavras-chave: Phytoplankton; Chlorophylls. |
| Ano: 2013 |
URL: http://hdl.handle.net/1834/5922 |
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| Dufour, P.; Cremoux, Jl.; Slepoukha, M.. |
| "In vitro" enrichment experiments on natural populations have been used to determine the nutrients controlling the potential biomass of phytoplancton in the Ebrié coastal lagoon. The limiting nutrients were generally nitrogen, phosphorus and carbon, in this order ; in three cases out of eleven, P and N act simultaneously ; in an extreme eutrophication case, N, P and C were all limiting. No effect was observed following addition of metals, vitamins or chelators. The limitations deduced from the enrichment experiments show a. good agreement with the elementary composition of the external medium ; in waters potentially limited by N alone, the dissolved inorganic nutrients have a N : P ratio lower than 25. The agreement is poorer when the sestonic N : P ratio... |
| Tipo: Text |
Palavras-chave: Lagune; Estuaire; Zone tropicale; Phytoplancton; Biomasse; Eléments limitants; Tests biologiques; Composition chimique; Coastal lagoon; Estuary tropical zone; Phytoplankton; Biomass; Limiting nutrients; Bioassay; Chemlcal composition. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00306/41689/40898.pdf |
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| Cruz, M.; Tapia, M.E.; Naranjo, Ch.. |
| Con la finalidad de determinar la influencia del evento El Niño 2009-2010 que se dsarrolló en elas regiones Niño 1+2 y 3.4, en base a los organismos indicadores de masas de aguas para determinar la intensidad y efectos en la costa ecuatoriana, se utilizaron cinco grupos de organismos planctónicos: Diatomeas, Dinoflagelados, Quetognatos, Pterópodos, Heterópodos y las concentraciones de clorofila a antes, durante y después del evento El Niño 2009-2010. En el primer trimestre del 2009 se registró una alta producción primaria, mientras que desde septiembre a noviembre se observó la más baja productividad del mar, en las estaciones fijas La Libertad como en Manta.En la estación fija de La Libertad, durante todo el 2009 predominaron especies de fitoplancton que... |
| Tipo: Journal Contribution |
Palavras-chave: Phytoplankton; Zooplankton; Indicator species; Diatoms; Primary production; El Nino phenomena; Water masses. |
| Ano: 2010 |
URL: http://hdl.handle.net/1834/4213 |
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| Negri, R.M.; Silva, R.I.; Segura, V.; Cucchi Colleoni, A.D.. |
| The El Rincón area in the Argentine continental shelf (coastal sector between 39º S-41º S) is known as one of the main breeding areas of the Argentine anchovy (Engraulis anchoita) Northern stock. However, there is scarce information regarding the structure of the primary producers, base of the pelagic food webs. The aim of this study was to identify the different phytoplanktonic communities in a coastal section in the area (depth lower than 60 m) during February 2011. Mean surface chlorophyll a concentration was 0.72 mg m-3, with the highest value in the innermost station (E34: 1.84 mg m-3) and the lowest in the mid section (E31: 0.24 mg m-3). In depth, similar concentrations were registered, except for the deepest station where the maximum value was... |
| Tipo: Journal Contribution |
Palavras-chave: Phytoplankton; Nannoplankton; Community composition; Size; Chlorophylls. |
| Ano: 2013 |
URL: http://hdl.handle.net/1834/5491 |
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| Registros recuperados: 369 | |
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