Consulta: subjectFacets:"Irradiance"
Registros recuperados: 16
Data/hora: 07/06/2024 04:57:53

The use of high rate algal ponds for the treatment of marine effluent from a recirculating fish rearing system
Provedor de dados: 5
Autores: Pagand, Pascal; Blancheton, Jean-paul; Lemoalle, J; Casellas, C.
A high rate algal pond (HRAP) system was used to treat effluent from a recirculating sea water aquaculture system in southern France. Dicentrarchus labrax L. were farmed at a high density, with effluents containing an average of 10 mg L-1 dissolved inorganic nitrogen (DIN) and 1.3 mg L-1 reactive phosphorus (RP). On a yearly basis, the algal pond removed 59% of the dissolved nitrogen and 56% of the phosphorus input, which was converted into 3.3 kg DW m(-2) algae. Green macroalgae were dominant throughout the year and the algal biomass mirrored the seasonal changes in daily irradiance and temperature. This first year study supports the possibility of treating marine aquaculture wastes using HPAPs, although conditions will have to be found to mitigate the...
Tipo: Text
Palavras-chave: Nitrogen; Biofilters; Irradiance; Temperature; Photosynthesis; Growth; Culture; Chlorophyta; Nutrient Removal.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/2000/publication-515.pdf

In situ growth potential of the subtidal part of green tide forming Ulva spp. stocks
Provedor de dados: 5
Autores: Merceron, Michel; Antoine, Virginie; Auby, Isabelle; Morand, P.
Ulva spp., the algae most responsible for green tides in Brittany (France), are found on the foreshore and in the most beachward wave area (MBWA) of many bays during green tide phenomena. These algae have recently been seen drifting at greater depths (reaching -20 m). In view of the significant quantities of algae found at these depths, and the less favorable conditions for algal growth than in the intertidal zone, we attempted to determine if they could grow there. For that, during their maximum growth period (from May to July), algae were picked up at three stations located on the foreshore, in the MBWA and in the subtidal (deep) zones of the Bay of Douarnenez, and their nitrogen, carbon and chlorophyll a+b contents were determined, and their...
Tipo: Text
Palavras-chave: Nutrients; Irradiance; Photosynthesis; Ulva sp.; Algal blooms; Eutrophication.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3527.pdf

The Role of Sustained Photoprotective Non-photochemical Quenching in Low Temperature and High Light Acclimation in the Bloom-Forming Arctic Diatom Thalassiosira gravida
Provedor de dados: 5
Autores: Lacour, Thomas; Lariviere, Jade; Ferland, Joannie; Bruyant, Flavienne; Lavaud, Johann; Babin, Marcel.
Thalassiosira gravida is a major Arctic diatom responsible for the under-ice spring bloom. We investigated T. gravida physiological plasticity growing it at two temperatures (0 and 5°C) and under different light intensities typically found in its natural environment. T. gravida showed remarkable thermal- and photo-acclimatory plasticity including: low light saturation parameter for growth (KE) and photosynthesis (EK), low μmax but relatively high Chl a/C, low C/N, and decreasing light-saturated carbon fixation rate (PmC) with increasing growth irradiance. T. gravida also showed remarkable photoprotective features, namely a strong sustained non-photochemical quenching (NPQs, hour kinetics relaxation) supported by a high amount of xanthophyll cycle pigments....
Tipo: Text
Palavras-chave: Arctic diatom; Photosynthesis; Sustained NPQ; Irradiance; Temperature.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00462/57387/59468.pdf

Trophic dynamics of scleractinian corals: stable isotope evidence
Provedor de dados: 5
Autores: Tremblay, Pascale; Maguer, Jean-francois; Grover, Renaud; Ferrier-pages, Christine.
Reef-building corals form symbioses with dinoflagellates from the diverse genus Symbiodinium. This symbiotic association has developed adaptations to acquire and share nutrients, which are essential for its survival and growth in nutrient-poor tropical waters. The host is thus able to prey on a wide range of organic food sources (heterotrophic nutrition) whereas the symbionts acquire most of the inorganic nutrients (autotrophic nutrition). However, nutrient fluxes between the two partners remain unclear, especially concerning heterotrophically acquired carbon and nitrogen. We combined physiological measurements and pulse-chase isotopic labeling of heterotrophic carbon and nitrogen, as well as autotrophic carbon to track nutrient fluxes in two coral...
Tipo: Text
Palavras-chave: Autotrophy; Carbon; Heterotrophy; Irradiance; Isotopic labeling; Nitrogen; Stylophora pistillata; Symbiodinium; Symbiosis; Turbinaria reniformis.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00270/38145/73160.pdf

A Coupled Lagrangian-Earth System Model for Predicting Oil Photooxidation
Provedor de dados: 5
Autores: Vaz, Ana C; Faillettaz, Robin; Paris, Claire B.
During the Deepwater Horizon (DWH) blowout, photooxidation of surface oil led to the formation of persistent photooxidized compounds, still found in shoreline sediments a decade later. Studies demonstrated that photooxidation modified both biodegradation rates of the surface oil and the effectiveness of aerial dispersant applications. Despite the significant consequences of this weathering pathway, the lack of measurements prevented photooxidation to be accounted for in the DWH oil budget calculations and in most predictive models. Here we develop a Lagrangian photooxidation module that estimates the dose of solar radiation individual oil droplets receive while moving in the ocean, quantifies the likelihood of photooxidative changes, and continues to track...
Tipo: Text
Palavras-chave: Oil spill; Oil photooxidation; Irradiance; Oil weathering; Deepwater Horizon; Oil-Connectivity modeling System; Oil modeling.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00680/79177/81684.pdf

Microclimate and development of 'Conilon' coffee intercropped with rubber trees
Provedor de dados: 86
Autores: Partelli,Fábio Luiz; Araújo,André Vasconcellos; Vieira,Henrique Duarte; Dias,Jairo Rafael Machado; Menezes,Luis Fernando Tavares de; Ramalho,José Cochicho.
The objective of this work was to evaluate the influence of intercropping 'Conilon' coffee (Coffea canephora) with rubber trees on coffee tree microclimate, nutrition, growth, and yield. Rubber trees were planted in two double rows 33 m apart, with 4x2.3 m spacing between plants. Treatments consisted of the distances from the coffee plants to the rubber trees: 3, 6, 9, 12, and 15 m. Measurements of atmospheric variables (temperature, irradiance, and relative humidity), leaf nutrient concentration, internode length of plagiotropic and orthotropic branches, individual leaf area, chlorophyll content, and yield were performed. Intercropping promotes changes in the microclimatic conditions of coffee plants close to rubber trees, with reduction of temperature...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Coffea canéfora; Hevea brasiliensis; Irradiance; Monoculture; Shading.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2014001100872

High irradiance and temperature inhibit the germination of spores of the fern Rumohra adiantiformis (Forst.) Ching (Dryopteridaceae)
Provedor de dados: 88
Autores: BRUM,FRANCIS R.; RANDI,ÁUREA M.
Rumohra adiantiformis (Forst.) Ching is a fern (Dryopteridaceae) which is used to compose floral arrangements. Fertile fronds were harvested in the "Permanently Protected Area" of Ilha Comprida, São Paulo, Brazil. Sterilized spores were germinated in Mohr liquid medium modified by Dyer. The effect of 72%, 54%, 17% and 9% of total irradiance on germination under field conditions, was analyzed. Experiments were carried out in March (I), April (II) and August of 2000 (III). Under 54% and 72% of total irradiance in Experiment I (March) the germination was completely inhibited and partially inhibited under 72% of total irradiance in Experiment II (April). The lowest mean germination time (&lt;img border=0 width=10 height=12 id="_x0000_i1025"...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Germination; Irradiance; Rumohra adiantiformis; Temperature.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042002012000002

Crescimento inicial de Piptadenia gonoacantha (Leguminosae, Mimosoideae) sob inundação em diferentes níveis de luminosidade
Provedor de dados: 88
Autores: FERREIRA,JOICE NUNES; RIBEIRO,JOSÉ FELIPE; FONSECA,CARLOS EDUARDO LAZARINI DA.
Este estudo aborda aspectos ecológicos da inundação em plântulas de Piptadenia gonoacantha, uma espécie ocorrente em Matas de Galeria. O crescimento de plântulas com cinco meses de idade foi avaliado em duas condições de solo (capacidade de campo e inundado) combinados com três níveis de luz solar (100%, 70% e 40%). A inundação reduziu o crescimento aéreo e radicial das plântulas. Não houve interação entre luz e inundação, exceto para massa seca foliar aos 60 dias e razão parte aérea/raiz aos 20 dias. Plântulas inundadas a pleno sol apresentaram massa seca foliar aos 60 dias cerca de 67% menor que aquelas inundadas sombreadas. A razão parte aérea/raiz de plântulas inundadas foi significativamente maior aos 60 dias. Plântulas inundadas produziram lenticelas...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Gallery Forest; Flooding tolerance; Irradiance; Piptadenia gonoacantha.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042001000500011

Photosynthetic characteristics of the freshwater red alga Batrachospermum delicatulum (Skuja) Necchi &amp;amp; Entwisle
Provedor de dados: 39
Autores: Necchi Júnior,Orlando; Alves,Abner H.S.
Six populations of the freshwater red alga Batrachospermum delicatulum (Skuja) Necchi &amp;amp; Entwisle, including gametophyte and 'Chantransia' stage, were analysed in culture and natural conditions applying chlorophyll fluorescence and oxygen evolution. Parameters derived from the photosynthesis-irradiance curves indicated adaptation to low irradiance for all populations, which was characterized by photoinhibition, low values of Ik and Ic and high values of a. Data from both techniques revealed significant differences among populations and phases for most photosynthetic parameters. Similarly, photosynthesis responded differently to variations in temperature in each population with similar rates under a wide range of temperature. No consistent pattern...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Batrachospermum; Photosynthesis; Irradiance; PH; Diurnal rhythm; Temperature.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062005000100012

Effects of sucrose and irradiance on germination and early gametophyte growth of the endangered tree fern Dicksonia sellowiana Hook (Dicksoniaceae)
Provedor de dados: 39
Autores: Renner,Gladys Daniela Rogge; Randi,Áurea Maria.
It is an endangered tree fern that grows in mixed umbrophylus forests in the tropics. Sterilized spores were germinated at 25 ± 2ºC under a 16-hour photoperiod, in Dyer and MS medium supplemented with 0 to 5% sucrose. The germination was lower with the addition of sucrose. Dry mass was higher in 30-day-old gametophytes cultivated in Dyer medium with the addition of 3 to 5% of sucrose. The dry mass decreased in 30-day-old gametophytes cultivated in Dyer and MS media without sucrose and in MS medium with the addition of 4 or 5% of sucrose. The effect of different irradiance on the germination and early gametophyte development of D. sellowiana was analyzed in the autumn of 1998 (May until July). Conical flasks containing spores were kept over a period of 49...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sugar; Chlorophyll; Gametophyte; Germination; Irradiance.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062004000200017

Performance study of a standalone direct pumping photovoltaic system used for drip irrigation
Provedor de dados: 111
Autores: HARKANI, ASSIA; El Aissaoui, Abdellah.
This paper aims to study performances of a standalone photovoltaic pumping system confronted to actual behaviour of incident irradiance. The system is based on a photovoltaic generator, a MPPT/ DC-DC converter, and a diaphragm DC motor pump connected to calibrated ( Flow versus Pressure) orifices, simulating small drip irrigation network, mounted in parallel scheme to vary the pump operating point according to timely varied irradiance. The result showed  that daily trend of solar irradiance influence considerably operating behaviour of the pump, consequently the performance of the standalone PV system is affected as there is inadequation between charges of the PV generator and the DC pump.  The hydraulic effeciency trends showed a dispersion and varying...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Agricultural engineering; Enegy in agriculture Standalone; Photovoltaic pumping system; Performances; Irradiance; Efficiency; MPPT; DC pump.
Ano: 2019
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/4822

Effects of abiotic stress on biomass and anthocyanin production in cell cultures of Melastoma malabathricum
Provedor de dados: 48
Autores: CHAN,L. K; KOAY,S. S; BOEY,P. L; BHATT,A.
Plant cell cultures could be used as an important tool for biochemical production, ranging from natural coloring (pigments) to pharmaceutical products. Anthocyanins are becoming a very important alternative to synthetic dyes because of increased public concern over the safety of artificial food coloring agents. Several factors are responsible for the production of anthocynin in cell cultures. In the present study, we investigate the effects of different environmental factors, such as light intensity, irradiance (continuous irradiance or continuous darkness), temperature and medium pH on cell biomass yield and anthocyanin production in cultures of Melastoma malabathricum. Moderate light intensity (301 - 600 lux) induced higher accumulation of anthocyanins...
Tipo: Journal article
Palavras-chave: Irradiance; Medium pH; Photoperiod; Temperature; Melastoma malabathricum.
Ano: 2010
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602010000100014

Growth, photosynthesis and leaf water potential in young plants of Copaifera langsdorffii Desf. (Caesalpiniaceae) under contrasting irradiances
Provedor de dados: 61
Autores: Ronquim,Carlos Cesar; Prado,Carlos Henrique B. A.; Souza,João Paulo de.
Growth and leaf nutrient content were compared in young potted plants of Copaifera langsdorffii in sunny and shaded areas without water stress. Besides, carbon assimilation and leaf water relations were evaluated by net photosynthesis, potential photochemical efficiency and leaf water potential during daily courses in dry and rainy periods under natural conditions in both contrasting irradiances. Higher values of total biomass, height and leaf area occurred in sunny than in shaded area. On the other hand, all young plants survived in shade under natural water stress probably by reason of fast and intense biomass accumulation in favor of roots in early development. There was no significant difference about nutrient concentration in leaves between plants...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cerrado; Biomass partitioning; Chlorophyll fluorescence; Leaf gas exchange; Irradiance; Sunflecks.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202009000300004

Shoot-foliage relationships in deciduous, semideciduous, and evergreen cerrado tree species
Provedor de dados: 61
Autores: Souza,João Paulo; Prado,Carlos Henrique B. A.; Albino,Ana Lúcia S.; Damascos,Maria A.
The morphology and the biomass allocation in shoots and leaves were investigated in 15 cerrado tree species with distinct leaf phenology growing under natural conditions. Higher values of leaf/shoot ratio on mass base, individual leaf area, leaf area per shoot, leaf display index, and leaf number per shoot length were found in deciduous than in evergreen species. The differences about shoot-foliage relationship across leaf phenological groups could be explained by plagiotropic shoots on deciduous and by erect shoots in semideciduous and evergreen species. Plagiotropic shoots allow similar irradiance along shoots and high biomass allocation in favor of leaves without foliage self-shading in deciduous tree species. The structural differentiation between...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Biomass allocation; Cerrado; Deciduousness; Irradiance; Leaf area; Orthotropic; Plagiotropic; Shoot.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202009000100009

Photoacclimation in three species of freshwater red algae
Provedor de dados: 61
Autores: Bautista,Anna I.N.; Necchi Jr.,Orlando.
Three freshwater Rhodophyta species (Audouinella eugenea, A. hermannii and Compsopogon coeruleus) were tested as to their responses (photosynthesis, growth and pigment concentration) to two irradiances (low light, LL, 65 µmol m-2 s-1 and high light, HL, 300 µmol m-2 s-1) and two periods (short time, ST, 4 d, and long time, LT, 28 d). Higher growth rates were consistently observed at LL but significant differences were observed only for A. hermannii. Higher values of photoinhibition at LL were found for the three species, which is consistent with the dynamic photoinhibition as a reversible photoprotective mechanism against high irradiance. Light-induced decreases of effective quantum yield (EQY) were observed in the three species consisting of pronounced...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chlorophyll fluorescence; Growth; Irradiance; Photosynthesis; Pigment; Red algae.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202007000100003

Photosynthetic characteristics of a tropical population of Nitella cernua (Characeae, Chlorophyta)
Provedor de dados: 61
Autores: Vieira Jr.,Jair; Necchi Jr.,Orlando.
Photosynthetic characteristics (assessed by chlorophyll fluorescence and O2 evolution) were analysed monthly during one year in a tropical population of Nitella cernua from southeastern Brazil (20º50'32" S, 49º26'15" W). Parameters derived from photosynthesis-irradiance (PI) curves by fluorescence (high values of the photosynthetic parameter, Ik, and lack or low values of photoinhibition, beta) suggested adaptation to high irradiance, whereas those by O2 evolution showed a different pattern (low values of Ik and compensation irradiance, Ic, high values of photosynthetic efficiency, alpha, and photoinhibition). Parameters from PI curves by O2 evolution suggested light acclimation: Ik and maximum photosynthetic rate, Pmax (as rETR, relative electron transfer...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Charophytes; Irradiance; Nitella; PH; Photosynthesis; Seasonal dynamics; Temperature.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202006000300004