Consulta: subjectFacets:"Nutrient limitation"
Registros recuperados: 7
Data/hora: 10/06/2024 18:02:56

Phytoplankton strategies to exploit nutrients in coastal lagoons with different eutrophication status during re-oligotrophication
Provedor de dados: 5
Autores: Leruste, A; Guilhaumon, F; De Wit, R; Malet, Nathalie; Collos, Y; Bec, Beatrice.
We studied a mesotrophic and a hypertrophic Mediterranean coastal lagoon, both of which had been simultaneously subjected to a nutrient input reduction for 9 yr. We compared these 2 lagoons to an oligotrophic coastal lagoon. Using bioassays comprising 24 h incubations with added phosphorus and/or ammonium, we investigated the response of the phytoplankton communities to nutrient enrichment during summer in terms of biomass, size class structure, abundance and growth. For nitrogen and phosphorus, we identified which nutrient limited phytoplankton growth, and what strategies of nutrient exploitation the communities adopted to cope with these limitations. Ultraphytoplankton dominated the 3 communities, but it differed in composition among the lagoons. Green...
Tipo: Text
Palavras-chave: Growth rate; Nutrient limitation; Dilution experiment; HPLC.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00508/61978/66084.pdf

Rôle des sédiments dans le cycle des nutriments et impacts sur l’eutrophisation des écosystèmes côtiers
Provedor de dados: 5
Autores: Ratmaya, Widya.
Eutrophication was studied in the coastal waters of Vilaine Bay (VB) in relation to that in the Loire and Vilaine rivers, by analyzing long-term trends of phytoplankton biomass and nutrient concentrations during the past decades. The reduction in dissolved riverine inorganic phosphorus concentrations (DIP) during the last two decades led to the significant decrease in chlorophyll a concentrations. However, dissolved inorganic nitrogen concentrations (DIN) decreased only slightly in the Vilaine and actually increased in the Loire, especially during summer. Simultaneously, phytoplankton in VB has undergone the following changes: 1) increase in biomass, 2) change in timing of the annual peak of biomass from spring to summer, 3) modification in seasonal course...
Tipo: Text
Palavras-chave: Eutrophisation; Cycle des nutriments; Régénération benthique; Nutriment limitant; Baie de Vilaine; Eutrophication; Nutrient cycling; Benthic regeneration; Nutrient limitation; Vilaine Bay.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00476/58799/61337.pdf

Optimizing conditions for the continuous culture of Isochrysis affinis galbana relevant to commercial hatcheries
Provedor de dados: 5
Autores: Marchetti, Julie; Bougaran, Gael; Le Dean, Loic; Megrier, Cyril; Lukomska, Ewa; Kaas, Raymond; Olivo, Erell; Baron, Regis; Robert, Rene; Cadoret, Jean-paul.
Optimal culture conditions were investigated for the continuous culture of Isochrysis affinis galbana (T-Iso) by assessing the effects of irradiance, temperature, pH and nitrogen and phosphorus requirements. Assessment of the growth rate-irradiance relationship in a turbidostat experiment highlighted that an optimum irradiance efficiency for growth (E-mu) occurred at irradiance much lower than the saturating level. Furthermore, our modeling approach for productivity pointed out that an optimal set of irradiance and dilution rate could be achieved in order to maximize irradiance efficiency. Optimal conditions for growth were assessed for temperature, pH and irradiance by means of a factorial design experiment. The resulting model predicted that optimal...
Tipo: Text
Palavras-chave: Isochrysis affinis galbana; Irradiance efficiency; Factor interaction; Nutrient limitation; Microalgae cultures.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00076/18736/16465.pdf

Impacts of high-nitrate freshwater inputs on macrotidal ecosystems. I. Seasonal evolution of nutrient limitation for the diatom-dominated phytoplankton of the Bay of Brest (France)
Provedor de dados: 5
Autores: Del Amo, Yolanda; Le Pape, Olivier; Treguer, Paul; Queguiner, Bernard; Menesguen, Alain; Aminot, Alain.
The chemical factors (inorganic nitrogen, phosphate, silicic acid) that potentially or actually control primary production were determined for the Bay of Brest, France, a macrotidal ecosystem submitted to high-nitrate-loaded freshwater inputs (winter nitrate freshwater concentrations &gt;700 mu M, Si:N molar ratio as low as 0.2, i.e. among the lowest ever published). Intensive data collection and observations were carried out from February 1993 to March 1994 to determine the variations of physical [salinity, temperature, photosynthetically active radiation (PAR), freshwater discharges] and chemical (oxygen and nutrients) parameters and their impacts on the phytoplankton cycle (fluorescence, pigments, primary production). With insufficient PAR the winter...
Tipo: Text
Palavras-chave: Coastal ecosystem; Phytoplankton dynamics; Macrotidal; Nutrient limitation; Silicon; Eutrophication.
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00337/44782/44588.pdf

Phytoplankton phosphorus limitation in a North Atlantic coastal ecosystem not predicted by nutrient load
Provedor de dados: 5
Autores: Trommer, Gabriele; Leynaert, Aude; Klein, Cecile; Naegelen, Aurore; Beker, Beatriz.
Phytoplankton nutrient limitation patterns were investigated in an anthropogenically influenced coastal ecosystem with a high nutrient load. Weekly nutrient limitation bioassays, and water chemistry and stoichiometry measurements were performed in the Bay of Brest, France, from February to July 2011. Each limitation bioassay included phosphorus, nitrogen, silicate and all possible combined nutrient additions, and lasted over 72 h. Results showed that the phytoplankton community experienced a general P limitation from March to July. N limitation alone was observed only during 1 week in early March. Subsequently, all limitation bioassays revealed primary P limitation, indicated by significantly increased growth rates in all samples containing P additions....
Tipo: Text
Palavras-chave: Phytoplankton; Stoichiometry; Bioassays; Nutrient limitation; Coastal ecosystem.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00368/47947/48023.pdf

Agrowaste-based Polyhydroxyalkanoate (PHA) production using hydrolytic potential of Bacillus thuringiensis IAM 12077
Provedor de dados: 52
Autores: Gowda,Vaishnavi; Shivakumar,Srividya.
The study identified the innate enzymatic potential (amylase) of the PHB producing strain B.thuringiensis IAM 12077 and explored the same for cost-effective production of PHB using agrowastes, eliminating the need for pretreatment (acid hydrolysis and/or commercial enzyme). Comparative polyhydroxyalkanoate (PHA) production by B. thuringiensis IAM 12077 in biphasic growth conditions using glucose and starch showed appreciable levels of growth (5.7 and 6.8 g/L) and PHA production (58.5 and 41.5%) with a PHA yield of 3.3 and 2.8 g/L, respectively. Nitrogen deficiency supported maximum PHA yield (2.46 g/L) and accumulation (53.3%). Maximum growth (3.6 g/L), PHB yield (2.6 g/L) and PHA accumulation (72.8%) was obtained with C:N ratio of 8:1 using starch as the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bacillus thuringiensis IAM 12077; Polyhydroxybutyrate; Nutrient limitation; Hydrolytic enzymes; Mango peel.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132014000100009

Chlorophyll fluorescence response of Pinus radiata clones to nitrogen and phosphorus supply
Provedor de dados: 118
Autores: Bown,Horacio E; Mason,Euan G; Clinton,Peter W; Watt,Michael S.
Chlorophyll fluorescence responses to a factorial combination of nitrogen (N) and phosphorus (P) supply were measured in five clones of Pinus radiata cultivated in a greenhouse over twenty-four months. Chlorophyll fluorescence measurements were taken at months six (5 clones, 182 plants), nine (2 clones, 68 plants) and eighteen (2 clones, 48 plants). Plant growth in stem diameter, height, leaf area, fascicle mass, length and diameter were found to significantly increase with N and, to a lesser extent, P additions; and these values were greatest when both N and P were combined. Plant growth and fascicle size also varied significantly across clones and were generally consistent with the genotypic growth responses that were observed in the field. Dark (Fv /...
Tipo: Journal article
Palavras-chave: Chlorophyll fluorescence; Quantum efficiency of PSII; Electron transport; Genotype; Nutrient limitation.
Ano: 2009
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202009000300012