Academic literature on the topic 'Phytoplankton quantum yield for growth'
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Journal articles on the topic "Phytoplankton quantum yield for growth"
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Behrenfeld, M. J., T. K. Westberry, E. S. Boss, R. T. O'Malley, D. A. Siegel, J. D. Wiggert, B. A. Franz, et al. "Satellite-detected fluorescence reveals global physiology of ocean phytoplankton." Biogeosciences 6, no. 5 (May 8, 2009): 779–94. http://dx.doi.org/10.5194/bg-6-779-2009.
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Abstract. Phytoplankton photosynthesis links global ocean biology and climate-driven fluctuations in the physical environment. These interactions are largely expressed through changes in phytoplankton physiology, but physiological status has proven extremely challenging to characterize globally. Phytoplankton fluorescence does provide a rich source of physiological information long exploited in laboratory and field studies, and is now observed from space. Here we evaluate the physiological underpinnings of global variations in satellite-based phytoplankton chlorophyll fluorescence. The three dominant factors influencing fluorescence distributions are chlorophyll concentration, pigment packaging effects on light absorption, and light-dependent energy-quenching processes. After accounting for these three factors, resultant global distributions of quenching-corrected fluorescence quantum yields reveal a striking consistency with anticipated patterns of iron availability. High fluorescence quantum yields are typically found in low iron waters, while low quantum yields dominate regions where other environmental factors are most limiting to phytoplankton growth. Specific properties of photosynthetic membranes are discussed that provide a mechanistic view linking iron stress to satellite-detected fluorescence. Our results present satellite-based fluorescence as a valuable tool for evaluating nutrient stress predictions in ocean ecosystem models and give the first synoptic observational evidence that iron plays an important role in seasonal phytoplankton dynamics of the Indian Ocean. Satellite fluorescence may also provide a path for monitoring climate-phytoplankton physiology interactions and improving descriptions of phytoplankton light use efficiencies in ocean productivity models.
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Fanesi, Andrea, Heiko Wagner, and Christian Wilhelm. "Phytoplankton growth rate modelling: can spectroscopic cell chemotyping be superior to physiological predictors?" Proceedings of the Royal Society B: Biological Sciences 284, no. 1848 (February 8, 2017): 20161956. http://dx.doi.org/10.1098/rspb.2016.1956.
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Climate change has a strong impact on phytoplankton communities and water quality. However, the development of robust techniques to assess phytoplankton growth is still in progress. In this study, the growth rate of phytoplankton cells grown at different temperatures was modelled based on conventional physiological traits (e.g. chlorophyll, carbon and photosynthetic parameters) using the partial least square regression (PLSR) algorithm and compared with a new approach combining Fourier transform infrared-spectroscopy and PLSR. In this second model, it is assumed that the macromolecular composition of phytoplankton cells represents an intracellular marker for growth. The models have comparable high predictive power ( R 2 > 0.8) and low error in predicting new observations. Interestingly, not all of the predictors present the same weight in the modelling of growth rate. A set of specific parameters, such as non-photochemical fluorescence quenching (NPQ) and the quantum yield of carbon production in the first model, and lipid, protein and carbohydrate contents for the second one, strongly covary with cell growth rate regardless of the taxonomic position of the phytoplankton species investigated. This reflects a set of specific physiological adjustments covarying with growth rate, conserved among taxonomically distant algal species that might be used as guidelines for the improvement of modern primary production models. The high predictive power of both sets of cellular traits for growth rate is of great importance for applied phycological studies. Our approach may find application as a quality control tool for the monitoring of phytoplankton populations in natural communities or in photobioreactors.
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Sinoir, Marie, Andrew R. Bowie, Mathieu Mongin, Edward C. V. Butler, and Christel S. Hassler. "Zinc requirement for two phytoplankton strains of the Tasman Sea." Marine and Freshwater Research 68, no. 2 (2017): 361. http://dx.doi.org/10.1071/mf15323.
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Zinc has been proposed as a limiting, or co-limiting, micronutrient for phytoplankton. In the Tasman Sea, extremely low zinc concentrations have been reported, raising the possibility there of limitation of phytoplankton growth by zinc. The pennate diatom Nitzschia closterium (CS-1) and the coccolithophorid Emiliania huxleyi (CS-812) were cultured in two low zinc concentrations (Zn2+ = 1.5 pmolL–1 and Zn2+ = 1.5 nmolL–1) mimicking conditions found in coastal and pelagic Tasman Sea. To monitor phytoplankton health and productivity, the maximum quantum yield (Fv/Fm), growth rate and cell size were analysed. These parameters showed that both strains were able to adapt and still grow. Short-term uptake experiments revealed an effect on Zn biological transport, with consequences for its bioavailability. When grown at low Zn2+ concentrations, E. huxleyi showed an induction of a two-transporter system, highly dependent on photosynthetic energy for Zn uptake. N. closterium was able to survive without inducing a higher-affinity Zn transporter. Its Zn uptake was also highly dependent on cellular energy and the ability to potentially access labile complexed forms of Zn. This strategy, thus, represented an advantage over E. huxleyi. Results are discussed in the context of the conditions found in the Tasman Sea.
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Kim, J. H., K. Y. Kim, E. J. Kang, K. Lee, J. M. Kim, K. T. Park, K. Shin, B. Hyun, and H. J. Jeong. "Enhancement of photosynthetic carbon assimilation efficiency by phytoplankton in the future coastal ocean." Biogeosciences 10, no. 11 (November 21, 2013): 7525–35. http://dx.doi.org/10.5194/bg-10-7525-2013.
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Abstract. A mesocosm experiment was conducted to evaluate the influence of photosynthetic performance on the energetic balance of coastal phytoplankton, in relation to community production and autotrophic phytoplankton biomass in future coastal oceans. Natural phytoplankton assemblages were incubated in field mesocosms under ambient condition (control: ca. 400 μatm CO2 and ambient temperature), and two sets of potential future ocean conditions (acidification: ca. 900 μatm CO2 and ambient temperature; greenhouse: ca. 900 μatm CO2 and 3 °C warmer). The photosynthetic performances were estimated by in vivo fluorometry (effective quantum yield (ΦPSII), steady-state light response curves (LCs)) and in situ incorporation of 14C (photosynthesis-irradiance curves). The ΦPSII and rETRm,LC (relative maximum electron transport rate) clearly reduced under acidification, in particular, when phytoplankton were exposed to high light levels. However, PBmax (maximum photosynthetic rate) was the same in the ambient and acidification conditions. Thus, phytoplankton utilized less light under acidification condition, but could still assimilate a similar amount of carbon compared to the ambient condition. The PBmax and α (photosynthetic efficiency) under greenhouse condition were significantly higher than those under ambient condition without any difference in ΦPSII, rETRm,LC and α,LC (electron transport efficiency) between the treatments. Therefore, phytoplankton utilized the same amount of light under greenhouse condition, but could assimilate more carbon than under ambient condition. As a result, Chl a normalized primary production was higher in greenhouse than in other conditions. Nevertheless, the community production did not change between the experimental treatments. The main reason for the lack of a change in primary production under future climate conditions is the control of autotrophic phytoplankton biomass by grazing. Consequently, acidification and greenhouse environments have a potential to increase growth and primary production of phytoplankton by enhancing inorganic carbon assimilation efficiency when top-down regulation is negligible.
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Li, Zhou, Philippe Juneau, Yingli Lian, Wei Zhang, Shanquan Wang, Cheng Wang, Longfei Shu, Qingyun Yan, Zhili He, and Kui Xu. "Effects of Titanium Dioxide Nanoparticles on Photosynthetic and Antioxidative Processes of Scenedesmus obliquus." Plants 9, no. 12 (December 10, 2020): 1748. http://dx.doi.org/10.3390/plants9121748.
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The effects of the photocatalytic toxicity of titanium dioxide nanoparticle (nano-TiO2) on phytoplankton are well understood. However, as UV light intensity decreases sharply with the depth of the water column, the effects of nano-TiO2 itself on deeper water phytoplankton, such as green algae, need further research. In this research, we investigated the effects of three sizes of TiO2 (10, 50 and 200 nm) on the photosynthetic and antioxidative processes of Scenedesmus obliquus in the absence of UV light. We found that 50 nm and 10 nm TiO2 (10 mg/L) inhibited growth rates and the maximal photosystem II quantum yield compared to the control in Scenedesmus obliquus. The minimal and maximal fluorescence yields, and the contents of reactive oxygen species and lipid peroxidation, increased, indicating that photosynthetic energy/electrons transferred to oxygen and induced oxidative stress in nano-TiO2-treated samples. In addition, we found that aggregations of algae and 10 nm TiO2 were present, which could induce cell membrane disruption, and vacuoles were induced to cope with nano-TiO2 stress in Scenedesmus obliquus. These results enhance our understanding of the effects of nano-TiO2 on the photosynthetic and antioxidative processes of green algae, and provide basic information for evaluating the ecotoxicity of nano-TiO2 in freshwater ecosystems.
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Guo, Jiaying Abby, Robert Strzepek, Anusuya Willis, Aaron Ferderer, and Lennart Thomas Bach. "Investigating the effect of nickel concentration on phytoplankton growth to assess potential side-effects of ocean alkalinity enhancement." Biogeosciences 19, no. 15 (August 5, 2022): 3683–97. http://dx.doi.org/10.5194/bg-19-3683-2022.
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Abstract. Ocean alkalinity enhancement (OAE) is a proposed method for removing carbon dioxide (CO2) from the atmosphere by the accelerated weathering of (ultra-)basic minerals to increase alkalinity – the chemical capacity of seawater to store CO2. During the weathering of OAE-relevant minerals relatively large amounts of trace metals will be released and may perturb pelagic ecosystems. Nickel (Ni) is of particular concern as it is abundant in olivine, one of the most widely considered minerals for OAE. However, so far there is limited knowledge about the impact of Ni on marine biota including phytoplankton. To fill this knowledge gap, this study tested the growth and photo-physiological response of 11 marine phytoplankton species to a wide range of dissolved Ni concentrations (from 0.07 to 50 000 nmol L−1). We found that the phytoplankton species were not very sensitive to Ni concentrations under the culturing conditions established in our experiments, but the responses were species-specific. The growth rates of 6 of the 11 tested species showed generally limited but still significant responses to changing Ni concentrations (36 % maximum change). Photosynthetic performance, assessed by measuring the maximum quantum yield (Fv/Fm) and the functional absorption cross-section (σPSII) of photosystem II (PSII), was sensitive to changing Ni in 3 out of 11 species (35 % maximum change) and 4 out of 11 species (16 % maximum change), respectively. The limited effect of Ni may be partly due to the provision of nitrate as the nitrogen source for growth as previous studies suggest higher sensitivities when urea is the nitrogen source. Furthermore, the limited influence may be due to the relatively high concentrations of synthetic organic ligands added to the growth media in our experiments. These ligands are commonly added to control trace metal bioavailability and therefore for example “free Ni2+” concentrations by binding the majority of the dissolved Ni. Our data suggest that dissolved Ni does not have a strong effect on phytoplankton under our experimental conditions, but we emphasize that a deeper understanding of nitrogen sources, ligand concentrations, and phytoplankton composition is needed when assessing the influence of Ni release associated with OAE.
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Durán-Romero, Cristina, Virginia E. Villafañe, Macarena S. Valiñas, Rodrigo J. Gonçalves, and E. Walter Helbling. "Solar UVR sensitivity of phyto- and bacterioplankton communities from Patagonian coastal waters under increased nutrients and acidification." ICES Journal of Marine Science 74, no. 4 (January 22, 2017): 1062–73. http://dx.doi.org/10.1093/icesjms/fsw248.
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The effects of ultraviolet radiation (UVR) under future expected conditions of acidification and increase in nutrient inputs were studied on a post-bloom phytoplankton and bacterioplankton community of Patagonian coastal waters. We performed an experiment using microcosms where two environmental conditions were mimicked using a cluster approach: present (ambient nutrients and pH) and future (increased nutrients and acidification), and acclimating the samples for five days to two radiation treatments (full solar radiation [+UVR] and exclusion of UVR [–UVR]). We evaluated the short-term (hours) sensitivity of the community to solar UVR through chlorophyll a fluorescence parameters (e.g. the effective photochemical quantum yield of PSII [ΦPSII]) at the beginning, at the mid-point and at the end of the acclimation period. Primary production and heterotrophic bacterial production (HBP) were determined, and biological weighting functions were calculated, at the beginning and at the end of the acclimation period. Mid-term effects (days) were evaluated as changes in taxonomic composition, growth rates and size structure of the community. Although the UVR-induced inhibition on ΦPSII decreased in both clusters, samples remained sensitive to UVR after the 5 days of acclimation. Also, under the future conditions, there was, in general, an increase in the phytoplankton carbon incorporation rates along the experiment as compared to the present conditions. Bacterioplankton sensitivity to UVR changed along the experiment from inhibition to enhancement of HBP, and future environmental conditions stimulated bacterial growth, probably due to indirect effects caused by phytoplankton. Those changes in the microbial loop functioning and structure under future global change conditions might have important consequences for the carbon pump and thus for the carbon sequestration and trophodynamics of Patagonian coastal waters.
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Li, Futian, John Beardall, and Kunshan Gao. "Diatom performance in a future ocean: interactions between nitrogen limitation, temperature, and CO2-induced seawater acidification." ICES Journal of Marine Science 75, no. 4 (January 4, 2018): 1451–64. http://dx.doi.org/10.1093/icesjms/fsx239.
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Abstract Phytoplankton cells living in the surface waters of oceans are experiencing alterations in environmental conditions associated with global change. Given their importance in global primary productivity, it is of considerable concern to know how these organisms will perform physiologically under the changing levels of pH, temperatures, and nutrients predicted for future oceanic ecosystems. Here we show that the model diatom, Thalassiosira pseudonana, when grown at different temperatures (20 or 24 °C), pCO2 (400 or 1000 µatm), and nitrate concentrations (2.5 or 102.5 µmol l−1), displayed contrasting performance in its physiology. Elevated pCO2 (and hence seawater acidification) under the nitrate-limited conditions led to decreases in specific growth rate, cell size, pigment content, photochemical quantum yield of PSII, and photosynthetic carbon fixation. Furthermore, increasing the temperature exacerbated the negative effects of the seawater acidification associated with elevated pCO2 on specific growth rate and chlorophyll content under the N-limited conditions. These results imply that a reduced upward transport of nutrients due to enhanced stratification associated with ocean warming might act synergistically to reduce growth and carbon fixation by diatoms under progressive ocean acidification, with important ramifications for ocean productivity and the strength of the biological CO2 pump.
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Budzałek, Gracjana, Sylwia Śliwińska-Wilczewska, Marek Klin, Kinga Wiśniewska, Adam Latała, and Józef Maria Wiktor. "Changes in Growth, Photosynthesis Performance, Pigments, and Toxin Contents of Bloom-Forming Cyanobacteria after Exposure to Macroalgal Allelochemicals." Toxins 13, no. 8 (August 23, 2021): 589. http://dx.doi.org/10.3390/toxins13080589.
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Macroalgae can directly restrict the growth of various phytoplankton species by releasing allelopathic compounds; therefore, considerable attention should be paid to the allelopathic potential of these organisms against harmful and bloom-forming cyanobacteria. The main aim of this study was to demonstrate for the first time the allelopathic activity of Ulva intestinalis on the growth, the fluorescence parameters: the maximum PSII quantum efficiency (Fv/Fm) and the effective quantum yield of PSII photochemistry (ΦPSII), the chlorophyll a (Chl a) and carotenoid (Car) content, and the microcystin-LR (MC-LR) and phenol content of three bloom-forming cyanobacteria, Aphanizomenon sp., Nodularia spumigena, and Nostoc sp. We found both negative and positive allelopathic effects of U. intestinalis on tested cyanobacteria. The study clearly showed that the addition of the filtrate of U. intestinalis significantly inhibited growth, decreased pigment content and Fv/Fm and ΦPSII values of N. spumigena and Nostoc sp., and stimulated Aphanizomenon sp. The addition of different concentrations of aqueous extract also stimulated the cyanobacterial growth. It was also shown that the addition of extract obtained from U. intestinalis caused a significant decrease in the MC-LR content in Nostoc sp. cells. Moreover, it the phenol content in N. spumigena cells was increased. On the other hand, the cell-specific phenol content for Aphanizomenon sp. decreased due to the addition of the filtrate. In this work, we demonstrated that the allelopathic effect of U. intestinalis depends on the target species’ identity as well as the type of allelopathic method used. The study of the allelopathic Baltic macroalgae may help to identify their possible role as a significant biological factor influencing harmful cyanobacterial blooms in brackish ecosystems.
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Li, Futian, Jiekai Xu, John Beardall, and Kunshan Gao. "Diurnally fluctuating pCO2 enhances growth of a coastal strain of Emiliania huxleyi under future-projected ocean acidification conditions." ICES Journal of Marine Science 78, no. 4 (March 4, 2021): 1301–10. http://dx.doi.org/10.1093/icesjms/fsab036.
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Abstract The carbonate chemistry in coastal waters is more variable compared with that of open oceans, both in magnitude and time scale of its fluctuations. However, knowledge of the responses of coastal phytoplankton to dynamic changes in pH/pCO2 has been scarcely documented. Hence, we investigated the physiological performance of a coastal isolate of the coccolithophore Emiliania huxleyi (PML B92/11) under fluctuating and stable pCO2 regimes (steady ambient pCO2, 400 μatm; steady elevated pCO2, 1200 μatm; diurnally fluctuating elevated pCO2, 600–1800 μatm). Elevated pCO2 inhibited the calcification rate in both the steady and fluctuating regimes. However, higher specific growth rates and lower ratios of calcification to photosynthesis were detected in the cells grown under diurnally fluctuating elevated pCO2 conditions. The fluctuating pCO2 regime alleviated the negative effects of elevated pCO2 on effective photochemical quantum yield and relative photosynthetic electron transport rate compared with the steady elevated pCO2 treatment. Our results suggest that growth of E. huxleyi could benefit from diel fluctuations of pH/pCO2 under future-projected ocean acidification, but its calcification was reduced by the fluctuation and the increased concentration of CO2, reflecting a necessity to consider the influences of dynamic pH fluctuations on coastal carbon cycles associated with ocean global changes.
Dissertations / Theses on the topic "Phytoplankton quantum yield for growth"
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Setiapermana, Deddy. "Quantum yield of phytoplankton photosynthesis in relation to nutrient status." Thesis, Bangor University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.255408.
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Malick, Lisa A. "Light quality and phytoplankton viability." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000350.
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Monje, Oscar A. "Effects of Elevated CO2 on Crop Growth Rates, Radiation Absorption, Canopy Quantum Yield, Canopy Carbon Use Efficiency, and Root Respiration of Wheat." DigitalCommons@USU, 1993. https://digitalcommons.usu.edu/etd/6763.
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Wheat canopies were grown at either 330 or 1200 μmol mol-1 CO2 in sealed controlled environments, where carbon fluxes and radiation interception were continuously and nondestructively measured during their life cycles. The effects of elevated CO2 on daily growth rates, canopy quantum yield, canopy and root carbon use efficiencies, and final dry mass were calculated from carbon flux measurements in an open gas exchange system. Dry biomass at harvest was predicted from the gas exchange data to within ± 8%. The greatest effect of elevated CO2 occurred in the first 15d after emergence; however, several physiological processes were enhanced throughout the life cycle. Elevated CO2 increased average net photosynthesis by 30%, average shoot respiration by 10%, and average root respiration by 40%. Crop growth rate, calculated from gas exchange data, was 30% higher during both vegetative growth and reproductive growth. Elevated CO 2 did not affect radiation interception, but increased average canopy quantum yield from 0.039 to 0.051 (31%). Average canopy carbon use efficiency was increased by 12%. Although harvest index was unaffected, these increases in the physiological determinants of yield by elevated CO2 resulted in a 14% increase in seed yield.
Book chapters on the topic "Phytoplankton quantum yield for growth"
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Venediktov, Pavel S. "Regulation of the Quantum Yield of Photosynthesis in Chlorella During Nutrient Limited Growth." In Electromagnetic Fields and Biomembranes, 223–26. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4615-9507-6_36.
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Nikonova, Elena E., Evgeny A. Shirshin, Victor V. Fadeev, and Maxim Y. Gorbunov. "Advanced Procedure for Estimation of Phytoplankton Fluorescence Quantum Yield Using Remote Sensing Data: A Comparative Study of the Amundsen Sea Polynyas." In Springer Geology, 298–304. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-77788-7_31.
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Wilhelm, C., J. Bida, A. Domin, and M. Lohr. "Is the Measure of PSII Quantum Yield by Means of in-vivo Chl a-fluorescence really a direct Measure of Phytoplankton Primary Production?" In Photosynthesis: from Light to Biosphere, 4701–4. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-009-0173-5_1100.
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Kishino, Motoaki. "Interrelationships between Light and Phytoplankton in the Sea." In Ocean Optics. Oxford University Press, 1994. http://dx.doi.org/10.1093/oso/9780195068436.003.0008.
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Light energy penetrating the sea is diminished almost exponentially with depth with an accompanying drastic change in the energy spectrum as the result of absorption by various components in the seawater. Such a change in the light environment will affect phytoplankton life directly. Accordingly, in the study of light in the sea, much attention has been drawn toward the contribution of phytoplankton to the light field and also how much energy or which parts of the light spectrum are utilized at various depths by phytoplankton. Spectral distribution of underwater irradiance is determined by the processes of absorption and scattering from various components of the seawater. Since absorption plays a much more important role in spectral variation than scattering (Preisendorfer, 1961), the spectral absorption of each component should be studied in order to adequately interpret the variation of spectral irradiance in the sea. The materials absorbing light are phytoplankton, other particles, dissolved organic substances, and the water itself. Spectral characteristics of the light environment in the sea are determined by the variable ratios of these components. Several authors have attempted to measure directly the spectral absorption of individual components in seawater (Kirk, 1980; Okami et al., 1982; Kishino et al., 1984; Carder and Steward, 1985; Weidemann and Bannister, 1986). However, the determination of the absorption coefficient of natural phytoplankton is quite difficult, because no suitable technique is available for the direct measurement of absorption. Accordingly, there is still considerable uncertainty about light absorption by phytoplankton under natural conditions. Phytoplankton photosynthetic efficiency is important for the algae as well as the other organisms in the same ecosystem. Photosynthetic efficiency can be estimated fundamentally from quantum yield, which is obtained by measuring three parameters: photosynthetic rate, spectral downward irradiance, and the spectral absorption coefficient of phytoplankton. The optical system of a recently designed spectral irradiance meter is shown in Fig. 4-1. The meter has two independent cosine collectors that receive downward and upward spectral irradiance, respectively, by rotation of the mirror placed behind the collectors. After collimation, light reflected by the mirror is separated by a beam splitter.
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Mathivanan, Sivaji. "Perspectives of Nano-Materials and Nanobiosensors in Food Safety and Agriculture." In Novel Nanomaterials. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95345.
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Nanobiosensor is one type of biosensor made up with usage of nanomaterials i.e., nanoparticles and nanostructures. Because of the nanomaterials’ unique properties such as good conductivity, and physicochemical, electrochemical, optical, magnetic and mechanical properties, Nanobiosensors are highly reliable and more sensitive in biosensing approaches over conventional sensors which is having various limitation in detection. Quantum dots, nanotubes, nanowires, magnetic and other nanoparticles enhance sensitivity and lower limit of detection by amplifying signals and providing novel signal transduction mechanisms enable detection of a very low level of food contaminants, pesticides, foodborne pathogens, toxins and plant metabolites. Nanobiosensors are having a lot of scope in sustainable agriculture because of its detecting ability i.e., sensing changes occurred in molecular level. So it can be utilized to find out the variations or modification of plant metabolities, volatiles, gas exchange, hormonal and ion concentration etc. which are the indicators of various harsh environmental stresses (abiotic), biotic and physiological stress. Identification of the stress in the starting stage itself will help us to avoid intensive plant damage and prevent yield losses created by the stress. Nanosensors can be used in smart farming, in which all the environmental factors related to plant growth like temperature, water, pH, humidity, nutritional factor etc. are measured and precaution taken to control the factors which reduce the crop production with the help of IOT platform, thereby enhance the productivity. In this review, discussed about nanobiosensors for detection of food contaminants and various application and its potential in agriculture.
Conference papers on the topic "Phytoplankton quantum yield for growth"
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Kirkpatrick, Gary J., Dan Kamykowski, and Robert E. Reed. "Phytoplankton quantum yield measured on minute time scales in situ." In Ocean Optics XIII, edited by Steven G. Ackleson and Robert J. Frouin. SPIE, 1997. http://dx.doi.org/10.1117/12.266417.
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Chen, Y., J. E. Zucker, and T. H. Chiu. "Quantum-well modulators at 1.55 μm grown by single-step selective CBE." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oam.1992.thh3.
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In an effort to reduce the number of growth steps and increase device yield, we developed novel InGaAsP/InP quantum-well electro-optic modulators based on single-step growth on masked substrates by chemical beam epitaxy (CBE). The operating wavelengths of these devices are accurately tuned by controlling the CBE mask patterns. For the initial measurement we have fabricated patterned stripes on 3000 Å SiO2 with stripe width varying from 2 μm to 50 μm. A p-i-n structure with 20 InGaAsP/InP quantum wells lattice-matched to InP substrate was grown on n-type InP substrate. Rib waveguides were formed without any further processing. Excellent electroabsorption modulation was observed for these structures. We have measured an on/off ratio of 14.5 dB for a voltage swing of 10 V at 1.55 μm. In addition to the ease of fabrication and improved device yield, this technique also offers the unique tunability of the band edge of the waveguide by controlling the width of the SiO2 mask stripes. The photoluminescence spectrum of the rib waveguide shifts from 1464 nm to 1429 nm when the rib width is increased from 2 μm to 50 μm. The tunability is promising for laser-modulator integration without a complicated regrowth process.
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Sundyreva, M. A., A. N. Rebrov, A. E. Mishko, and E. O. Lutsky. "The effect of sucrose concentration in the culture medium on the formation of abscisic acid and the activity of the photosynthetic apparatus of grape plants in vitro." In 2nd International Scientific Conference "Plants and Microbes: the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.240.
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An increase in sucrose in the medium increased the content of pigments, gene expression of the photosynthetic apparatus, growth processes, and H2O2, but decreased the quantum yield of photosynthesis. With a change in the sucrose content in the medium, the expression of ABA1 increased most intensively. 30 g/l of sucrose in the medium inhibited the expression of genes involved in the formation of ABA.
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Horikoshi, Satoshi. "ELUCIDATION OF ELECTROMAGNETIC WAVE EFFECT AND OUTGOING OF FUTURE TREND IN MICROWAVE CHEMISTRY AND BIOLOGY." In Ampere 2019. Valencia: Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/ampere2019.2019.9783.
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The German chemist Theodor Grotthuss was the first to formulate the first law of photochemistry in 1817; he postulated that a reaction could be driven by light when the energy of light is absorbed by molecules [1]. After that, photochemistry has greatly contributed to the development of photography. In addition, second laws of photochemistry (Stark-Einstein law) was enacted, and these two laws have elevated photochemistry as an academic (science) discipline over the last one hundred years. In addition, because of advances in light sources and various devices (engineering), such materials and processes as photocatalysts, organic solar cells, photopolymerization, quantum dots, and photochromism (among others) are currently being applied in various other fields. The next significant surge in chemistry is microwave chemistry wherein microwaves, which represent electromagnetic waves other than light, were introduced as a driving force in the chemical reaction domain in the late 1980s. There are three characteristics in this chemistry when using microwaves. The first is the high heating efficiency caused by the energy of the microwaves that directly reach and are absorbed by the substance. The second is the selectivity with which a specific substrate is heated, while the third characteristic is the enhancement of chemical syntheses by the microwaves’ electromagnetic wave energy, often referred to as the microwave effect (or non-thermal effect). The phenomenon of the microwave effect (third characteristic) impacting chemical reactions has been summarized in much of the relevant literature, however, the reason why the microwave effect has not been clarified to anyone’s satisfaction is that the term microwave effect in microwave chemistry includes numerous factors. In order to fix microwaves in the chemical field, it is urgent to develop laws of “microwavechemistry”, and to do it is necessary to systematization against the phenomenas of electromagnetic waves for materials and reactions. One of the reasons for the dramatic growth in photochemistry is the development of high power laser technology. In recent years, coherent semiconductor generator with the generating high power microwaves have become easy to get, so “microwavechemistry” can proceed to the next stage. We examined that the phenomena as microwave electromagnetic waves in chemical reactions by using a semiconductor generator and a power sensor. And, it clarified that the reaction rate and yield of a very small part of the chemical reaction change with the unique phenomenon to electromagnetic waves [2]. On the other hand, generally, as plants, enzymes, biological substances temperature rises, it inhibits growth and reaction. This phenomenon was used to overcome the electromagnetic wave effect. We have succeeded in improving these activities by irradiating weak microwaves which do not increase these temperatures [3]. If microwave heating is given to them, it will work negatively. In this invited presentation, it introduces the possibility of electromagnetic wave effect(s) in these and explain its industrial application.