Search results for " Photosynthesis"

showing 10 items of 49 documents

Phototrophic Fe(II)-oxidation in the chemocline of a ferruginous meromictic lake

2014

Precambrian Banded Iron Formation (BIF) deposition was conventionally attributed to the precipitation of iron-oxides resulting from the abiotic reaction of ferrous iron (Fe(II)) with photosynthetically produced oxygen. Earliest traces of oxygen date from 2.7 Ga, thus raising questions as to what may have caused BIF precipitation before oxygenic photosynthesis evolved. The discovery of anoxygenic phototrophic bacteria thriving through the oxidation of Fe(II) has provided support for a biological origin for some BIFs, but despite reports suggesting that anoxygenic phototrophs may oxidize Fe(II) in the environment, a model ecosystem of an ancient ocean where they are demonstrably active was la…

Microbiology (medical)cryptic sulfur cyclingbiologyPhototrophEcologyanoxygenic photosynthesislcsh:QR1-502early life evolutionChlorobiumbiology.organism_classificationChemoclineAnoxygenic photosynthesisAnoxic watersMicrobiologylcsh:MicrobiologyFerrousWater column13. Climate actionEnvironmental chemistrybanded iron formationBanded iron formationOriginal Research ArticlegeomicrobiologyFrontiers in Microbiology
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Modification of Nanocrystalline WO3 with a Dicationic Perylene Bisimide: Applications to Molecular Level Solar Water Splitting

2015

[(N,N?-Bis(2-(trimethylammonium)ethylene) perylene 3,4,9,10-tetracarboxylic acid bisimide)(PF6)2] (1) was observed to spontaneously adsorb on nanocrystalline WO3 surfaces via aggregation/hydrophobic forces. Under visible irradiation (? > 435 nm), the excited state of 1 underwent oxidative quenching by electron injection (kinj > 108 s-1) to WO3, leaving a strongly positive hole (Eox ? 1.7 V vs SCE), which allows to drive demanding photo-oxidation reactions in photoelectrochemical cells (PECs). The casting of IrO2 nanoparticles (NPs), acting as water oxidation catalysts (WOCs) on the sensitized electrodes, led to a 4-fold enhancement in photoanodic current, consistent with hole transfer from …

Models MolecularMolecular ConformationNanoparticleImidesPhotochemistryBiochemistryTungstenCatalysisNOCatalysiElectron Transportchemistry.chemical_compoundColloid and Surface ChemistryTheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITYWO3ComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATIONperylenePhotoelectrochemical cellIrO2Quenching (fluorescence)Chemistry (all)charge transferWaterOxidesGeneral ChemistryPhotoelectrochemical cellPhotochemical ProcessesSolar fuelChemistry (all); Catalysis; Biochemistry; Colloid and Surface ChemistryNanocrystalline materialperylene WO3 charge transfer IrO2MicrosecondchemistryWater SplittingSunlightVISIBLE-LIGHT; ARTIFICIAL PHOTOSYNTHESIS; PHOTOELECTROCHEMICAL CELL; OXIDATION CATALYSTS; ELECTRON-TRANSFER; FABRICATIONNanoparticlesPerylene bisimideWater splittingPeryleneMathematicsofComputing_DISCRETEMATHEMATICS
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Seawater carbonate chemistry and kelp densities and coral coverages at three study locations and photosynthesis and calcification of corals measured …

2021

Ocean warming is altering the biogeographical distribution of marine organisms. In the tropics, rising sea surface temperatures are restructuring coral reef communities with sensitive species being lost. At the biogeographical divide between temperate and tropical communities, warming is causing macroalgal forest loss and the spread of tropical corals, fishes and other species, termed “tropicalization”. A lack of field research into the combined effects of warming and ocean acidification means there is a gap in our ability to understand and plan for changes in coastal ecosystems. Here, we focus on the tropicalization trajectory of temperate marine ecosystems becoming coral-dominated systems…

Ocean Acidification International Coordination Centre (OA-ICC)Net calcification rate of calcium carbonate lightCommunity composition and diversityAlkalinity total standard deviationunique identificationTemperature waterCarbon inorganic dissolvedNet calcification rate of calcium carbonateCalculated using seacarb after Nisumaa et al 2010Color descriptionRespiration rate oxygenpHRespirationMonthCarbonate ionLaboratory experimentField experimentRespiration rateunique identification URIstandard deviationlightAcropora solitaryensisCalcification/DissolutionCalcite saturation statewaterPartial pressure of carbon dioxideSiteGrowth MorphologyRocky-shore communityAragonite saturation state standard deviationPorites heronensisCarbon inorganic dissolved standard deviationTypeCalculated using seacarb after Nisumaa et al. (2010)Primary production PhotosynthesisSpeciesBottles or small containers/Aquaria (&lt;20 L)fungiEvent labeltechnology industry and agricultureCarbonate system computation flagpH standard deviationbiochemical phenomena metabolism and nutritionFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonPartial pressure of carbon dioxide water at sea surface temperature wet airEntire communitySingle speciesCalcification DissolutionBenthic animalsFugacity of carbon dioxide water at sea surface temperature wet airCoralCoast and continental shelfPhotosynthetic efficiencySpecies unique identification (URI)darkIdentificationRegistration number of speciesSalinityTemperateBottles or small containers/Aquaria (<20 L)inorganicAlkalinityArea localityNet photosynthesis rate oxygenExperimentArea/localityAragonite saturation stateNorth PacificAlkalinity totalBottles or small containers Aquaria 20 LtotalCO2 ventCalcification rate of calcium carbonateTemperaturedissolvedPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Temperature water standard deviationNet photosynthesis rateEarth System ResearchNet calcification rate of calcium carbonate darkField observationgeographic locationsSpecies unique identificationBenthosCnidariaDiameterOcean Acidification International Coordination Centre OA ICCAnimaliaBicarbonate ionGrowth ratePartial pressure of carbon dioxide standard deviationPrimary production/PhotosynthesisTreatmentCarbon dioxideGrowth/MorphologyRocky shore communityShootsoxygen
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Macroalgal responses to ocean acidification depend on nutrient and light levels

2015

Ocean acidification may benefit algae that are able to capitalize on increased carbon availability for photosynthesis, but it is expected to have adverse effects on calcified algae through dissolution. Shifts in dominance between primary producers will have knock-on effects on marine ecosystems and will likely vary regionally, depending on factors such as irradiance (light vs. shade) and nutrient levels (oligotrophic vs. eutrophic). Thus experiments are needed to evaluate interactive effects of combined stressors in the field. In this study, we investigated the physiological responses of macroalgae near a CO2 seep in oligotrophic waters off Vulcano (Italy). The algae were incubated in situ …

Ocean Acidification International Coordination Centre (OA-ICC)TemperateSalinityChlorophyll aFucoxanthininorganicAlkalinityPhotosynthetic efficiency standard errorChlorophyll cNitrogen content per dry mass standard errorLight saturation point standard errorPhenolics allTemperature waterCarbon inorganic dissolvedMacroalgaeCalculated using seacarb after Nisumaa et al 2010Carbon Nitrogen ratioAragonite saturation stateAlkalinity totalallCarbon per dry massSalinity standard errortotalCarbon content per dry mass standard errorPhenolics all standard errorCO2 ventChromistapHMaximum photochemical quantum yield of photosystem II standard errorTemperaturePartial pressure of carbon dioxide (water) at sea surface temperature (wet air) standard errordissolvedAntioxidant activity standard errorCarbonate ionMaximum photochemical quantum yield of photosystem IIPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Field experimentstandard errorNitrogen content per dry massElectron transport rate standard errorFucoxanthin standard errorEarth System ResearchViolaxanthinPhenolicsChlorophyll a standard errorCarbon dioxide standard errorPotentiometric titrationCalcite saturation stateCarbon/Nitrogen ratio standard errorNitrogenOchrophytaPotentiometricper dry masswaterChlorophyll c standard errorBenthosAlkalinity total standard errorAntioxidant activityElectron transport rateLight saturation pointOcean Acidification International Coordination Centre OA ICCMacro-nutrientsMediterranean SeaNitrogen per dry massBicarbonate ionTemperature water standard errorCalculated using seacarb after Nisumaa et al. (2010)Primary production PhotosynthesisSpeciespH standard errorCalcite saturation state standard errorCystoseira compressaCalculated using CO2SYSNon photochemical quenchingCarbon content per dry massCarbonate system computation flagViolaxanthin standard errorPrimary production/PhotosynthesisFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonCarbon/Nitrogen ratioBiomass/Abundance/Elemental compositionTreatmentPartial pressure of carbon dioxide water at sea surface temperature wet airAragonite saturation state standard errorCarbon dioxideMacro nutrientsCarbonate ion standard errorSingle speciesFugacity of carbon dioxide water at sea surface temperature wet airPadina pavonicaBiomass Abundance Elemental compositionCoast and continental shelfPhotosynthetic efficiencyBicarbonate ion standard errorNon photochemical quenching standard error
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Seagrass ecosystem response to long-term high CO2 in a Mediterranean volcanic vent

2014

We examined the long-term effect of naturally acidified water on a Cymodocea nodosa meadow growing at a shallow volcanic CO2 vent in Vulcano Island (Italy). Seagrass and adjacent unvegetated habitats growing at a low pH station (pH = 7.65 ± 0.02) were compared with corresponding habitats at a control station (pH = 8.01 ± 0.01). Density and biomass showed a clear decreasing trend at the low pH station and the below- to above-ground biomass ratio was more than 10 times lower compared to the control. C content and delta 13C of leaves and epiphytes were significantly lower at the low pH station. Photosynthetic activity of C. nodosa was stimulated by low pH as seen by the significant increase in…

Ocean Acidification International Coordination Centre (OA-ICC)TemperateSalinityChlorophyll ainorganicAlkalinityLight saturation point standard errorPhotosynthetic quantum efficiencyMediterranean Sea Acidification in a Changing Climate MedSeATemperature waterCarbon inorganic dissolvedCalculated using seacarb after Nisumaa et al 2010IrradianceRespiration rate carbonAragonite saturation stateBiomassAlkalinity totalIrradiance standard errortotalCO2 ventCymodocea nodosapHRespirationEpiphytes loadMaximum photochemical quantum yield of photosystem II standard errorNet community production of carbonTemperaturePartial pressure of carbon dioxide (water) at sea surface temperature (wet air) standard errordissolvedRespiration rate carbon standard errorCarbonate ionMaximum photochemical quantum yield of photosystem IIPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Net community production of carbon standard errorIlluminance standard errorSoft bottom communitystandard errorCarbon inorganic dissolved standard errorRespiration rateElectron transport rate standard errorEarth System Researchδ13CPhotosynthetic quantum efficiency standard errorField observationChlorophyll a standard errorGross primary production of carbonBiomass standard errorCalcium carbonatePotentiometric titrationCalcite saturation stateShoot densityPotentiometricwaterIlluminanceOxygen standard errorBenthosAlkalinity total standard errorMediterranean Sea Acidification in a Changing Climate (MedSeA)Electron transport rateLight saturation pointOcean Acidification International Coordination Centre OA ICCMediterranean SeaGross primary production of carbon standard errorBicarbonate ionSoft-bottom communityδ13C standard errorTemperature water standard errorCalculated using seacarb after Nisumaa et al. (2010)Primary production PhotosynthesisSpeciespH standard errorCarbonate system computation flagloadPrimary production/PhotosynthesisFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonBiomass/Abundance/Elemental compositionTreatmentEpiphytes load standard errorOxygenPartial pressure of carbon dioxide water at sea surface temperature wet airEpiphytes loadCarbon dioxideCarbon standard errorEntire communityFugacity of carbon dioxide water at sea surface temperature wet airGroupBiomass Abundance Elemental compositionCoast and continental shelfEpiphytesShoot density standard errorCalcium carbonate standard error
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TiO2 in Organic Photosynthesis: Sunlight Induced Functionalization of Heterocyclic Bases in the Presence of TiO2

2010

Organic photosynthesisSunlight Heterocyclic basas functionalization TiO2
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Exciton description of chlorosome to baseplate excitation energy transfer in filamentous anoxygenic phototrophs and green sulfur bacteria.

2013

A description of intra-chlorosome and from chlorosome to baseplate excitation energy transfer in green sulfur bacteria and in filamentous anoxygenic phototrophs is presented. Various shapes and sizes, single and multiwalled tubes, cylindrical spirals and lamellae of the antenna elements mimicking pigment organization in chlorosomes were generated by using molecular mechanics calculations, and the absorption, LD, and CD spectra of these were predicted by using exciton theory. Calculated absorption and LD spectra were similar for all modeled antenna structures; on the contrary, CD spectra turned out to be sensitive to the size and pigment orientations in the antenna. It was observed that, bri…

Physics::Biological PhysicsTime FactorsPhototrophbiologyChemistryExcitonChlorosomeModels Theoreticalbiology.organism_classificationMolecular physicsAnoxygenic photosynthesisSurfaces Coatings and FilmsChlorobiCrystallographyBacterial ProteinsEnergy TransferGreen sulfur bacteriaMaterials ChemistryPhysical and Theoretical ChemistryAntenna (radio)Organic ChemicalsAbsorption (electromagnetic radiation)ta116BacteriochlorophyllsExcitationThe journal of physical chemistry. B
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Influence of Content Knowledge on Pedagogical Content Knowledge: The case of teaching photosynthesis and plant growth

2009

International audience; Abstract The aim of the research was to investigate the effect of the amount and quality of content knowledge on pedagogical content knowledge (PCK). The biological content photosynthesis and plant growth was used as an example. The research sample consisted of 10 primary and 10 secondary (biology) teacher students. Questionnaires, lesson preparation task and an interview were used to collect data. Primary student teachers' were not aware of students' conceptual difficulties and had problems in choosing the most important content. Neither of the groups had knowledge on suitable experiments and demonstrations, which indicates that PCK should be explicitly taught. The …

Plant growthLehrende Erziehende LernendeContext effect4. EducationKnowledge level05 social sciencesContent knowledge Pedagogical content knowledge Photosynthesis and growth of plants Primary student teachers Secondary student teachers Teacher education050301 educationStudent teacherEducationddc:370PedagogyCurriculum Teaching DidacticsMathematics education0501 psychology and cognitive sciencesSocial Sciences & HumanitiesUnterricht DidaktikScience curriculumBildung und ErziehungTeachers Students PupilsContent knowledgePsychology0503 education050104 developmental & child psychologyInternational Journal of Science Education
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GROWTH PERFORMANCE AND PHYSIOLOGICAL TRAITS OF POSIDONIA OCEANICA EXPOSED TO A HYPERSALINE ENVIRONMENT

Posidonia oceanica Hypersaline stress Hypersaline lagoon Water relations Photosynthesis OsmolytesSettore BIO/07 - Ecologia
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Relationship between tree water status and physiology, yield, and fruit quality in the table olive (Olea europaea sativa L.) cultivar ‘Nocellara del …

2012

Although the olive (Olea europaea sativa l.) is considered a xerophytic species, long periods of water stress and high temperatures during summer months can greatly affect plant physiology and productivity. In recent years, the use of plant-based water status indicators have become popular in the study of plant-water relationships and in the design of irrigation programs, particularly midday stem water potential (ψstem). The current trend in the irrigation of olive trees is in the development of Deficit Irrigation (DI) systems whereby the water is applied at a rate which is lower than evapotranspiration needs, resulting in only very small reductions in yield. Rather than working towards min…

Settore AGR/03 - Arboricoltura Generale E Coltivazioni ArboreeRegulated Deficit Irrigation Stem Water Potential photosynthesis olive fruit caliber flesh/pit ratio
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