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Wyświetlanie 1-6 z 6
Tytuł:
Influence of non-photosynthetic pigments on the measured quantum yield of photosynthesis
Autorzy:
Ficek, D.
Majchrowski, R.
Ostrowska, M.
Wozniak, B.
Powiązania:
https://bibliotekanauki.pl/articles/47492.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
marine phytoplankton
pigment
quantum yield
chlorophyll a
phytoplankton pigment
bio-optical modelling
concentration
sea
water column
photosynthesis
Opis:
The aim of this work was to assess the effect of non-photosynthetic (photoprotecting) pigments on the measured quantum yield of photosynthesis in the sea. The energy absorbed by these pigments is not utilised during photosynthesis. As a result, the measured yield of this process, i.e. the photosynthetic yield referred to the total energy absorbed by all phytoplankton pigments, is less than the actual quantum yield of photosynthesis, i.e. the yield referred to the energy absorbed by photosynthetic pigments only. The model of the absorption properties of marine phytoplankton derived by the authors (see Woźniak et al. 2000, this volume) was employed to determine the relevant contributions of photosynthetic and non-photosynthetic pigments to the total energy absorbed by phytoplankton in different trophic types of seas and at different depths in the water column. On this basis the non-photosynthetic pigment absorption factor fa, which describes the relation between the true and measured quantum yields of photosynthesis, could be characterised. The analysis shows that fa varies in value from 0.33 to 1, and that it depends on the trophic type of sea and the depth in the water column. The values of this factor are usually highest in eutrophic waters and decrease as waters become progressively more oligotrophic. It is also characteristic of fa that it increases with increasing depth in the sea.
Źródło:
Oceanologia; 2000, 42, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dependence of the photosynthesis quantum yield in oceans on environmental factors
Autorzy:
Wozniak, B.
Dera, J.
Ficek, D.
Ostrowska, M.
Majchrowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/48279.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
primary production
water temperature
quantum yield
environmental factor
bio-optical modelling
nutrient content
phytoplankton
chlorophyll
irradiance
photosynthesis
Opis:
Statistical relationships between the quantum yield of photosynthesis and selected environmental factors in the ocean have been studied. The underwater irradiance, nutrient content, water temperature and water trophicity (i.e. the surface concentration of chlorophyll Ca(0)) have been considered, utilizing a large empirical data base. On the basis of these relationships, a mathematical model of the quantum yield was worked out in which the quantum yield Φ is expressed as a product of the theoretical maximum quantum yield ΦMAX = 0.125 atomC quanta−1 and six dimensionless factors. Each of these factors fi appears to be, to a sufficiently good approximation, dependent on one or two environmental factors and optical depth at most. The model makes it possible to determine the quantum yield from known values of these environmental factors. Empirical verification of the model yielded a positive result – the statistical error of the approximate values of the quantum yield Φ is 42%.
Źródło:
Oceanologia; 2002, 44, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling light and photosynthesis in the marine environment
Autorzy:
Wozniak, B.
Dera, J.
Ficek, D.
Majchrowski, R.
Ostrowska, M.
Kaczmarek, S.
Powiązania:
https://bibliotekanauki.pl/articles/47660.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
primary production
pigment
underwater irradiance
marine environment
quantum yield
remote sensing algorithm
bio-optical modelling
photoacclimation
phytoplankton
chromatic acclimation
light absorption
photosynthesis
Opis:
The overriding and far-reaching aim of our work has been to achieve a good understanding of the processes of light interaction with phytoplankton in the sea and to develop an innovative physical model of photosynthesis in the marine environment,suita ble for the remote sensing of marine primary production. Unlike previous models,the present one takes greater account of the complexity of the physiological processes in phytoplankton. We have focused in particular on photophysiological processes,whic h are governed directly or indirectly by light energy,or in which light, besides the nutrient content in and the temperature of seawater,is one of the principal limiting factors. To achieve this aim we have carried out comprehensive statistical analyses of the natural variability of the main photophysiological properties of phytoplankton and their links with the principal abiotic factors in the sea. These analyses have made use of extensive empirical data gathered in a wide diversity of seas and oceans by Polish and Russian teams as well as by joint Polish-Russian expeditions. Data sets available on the Internet have also been applied. As a result,a set of more or less complex,semi-empir ical models of light-stimulated processes occurring in marine phytoplankton cells has been developed. The trophic type of sea, photo-acclimation and the production of photoprotecting carotenoids,c hromatic acclimation and the production of various forms of chlorophyll-antennas and photosynthetic carotenoids,cell adaptation by the package effect, light absorption, photosynthesis, photoinhibition,the fluorescence effect,a nd the activation of PS2 centres are all considered in the models. These take into account not only the influence of light,but also, indirectly,tha t of the vertical mixing of water; in the case of photosynthesis,the quantum yield has been also formulated as being dependent on the nutrient concentrations and the temperature of seawater. The bio-optical spectral models of irradiance transmittance in case 1 oceanic waters and case 2 Baltic waters,dev eloped earlier,a lso are described in this paper. The development of the models presented here is not yet complete and they all need continual improvement. Nevertheless,w e have used them on a preliminary basis for calculating various photosynthetic characteristics at different depths in the sea,su ch as the concentration of chlorophyll and other pigments, and primary production. The practical algorithm we have constructed allows the vertical distribution of these characteristics to be determined from three input data: chlorophyll a concentration,irradiance, and temperature at the sea surface. Since all three data can be measured remotely,ou r algorithm can be applied as the ‘marine part’ of the remote sensing algorithms used for detecting marine photosynthesis.
Źródło:
Oceanologia; 2003, 45, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Practical applications of the multi-component marine photosynthesis model (MCM)
Autorzy:
Ficek, D.
Majchrowski, R.
Ostrowska, M.
Kaczmarek, S.
Wozniak, B.
Dera, J.
Powiązania:
https://bibliotekanauki.pl/articles/48509.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
primary production
quantum yield
inorganic nitrogen
temperate zone
tropical zone
practical application
bio-optical modelling
marine photosynthesis model
marine alga
polar zone
photosynthesis
Opis:
This paper describes the applications and accuracy analyses of our multi-component model of marine photosynthesis, given in detail in Woźniak et al. (2003). We now describe an application of the model to determine quantities characterising the photosynthesis of marine algae, especially the quantum yield of photosynthesis and photosynthetic primary production. These calculations have permitted the analysis of the variability of these photosynthesis characteristics in a diversity of seas, at different seasons, and at different depths. Because of its structure, the model can be used as the ‘marine part’ of a ‘satellite’ algorithm for monitoring primary production in the sea (the set of input data necessary for the calculations can be determined with remote sensing methods). With this in mind, in the present work, we have tested and verified the model using empirical data. The verification yielded satisfactory results: for example, the statistical errors in estimates of primary production in the water column for Case 1 Waters do not exceed 45%. Hence, this model is far more accurate than earlier, less complex models hitherto applied in satellite algorithms.
Źródło:
Oceanologia; 2003, 45, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model of the in vivo spectral absorption of algal pigments. Part 1. Mathematical apparatus
Autorzy:
Wozniak, B.
Dera, J.
Ficek, D.
Majchrowski, R.
Kaczmarek, S.
Ostrowska, M.
Koblentz-Mishke, O.I.
Powiązania:
https://bibliotekanauki.pl/articles/48333.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
chlorophyll a
bio-optical modelling
photosynthetic pigment
photoacclimation
sea water
algal pigment
in vivo
phytoplankton
mathematical apparatus
chromatic acclimation
light absorption
Opis:
Existing statistical models of in vivo light absorption by phytoplankton (Woźniak & Ostrowska 1990, Bricaud et al. 1995, 1998) describe the dependence of the phytoplankton specific spectral absorption coefficient a∗ pl(λ) on the chlorophyll a concentration Ca in seawater. However, the models do not take into account the variability in this relationship due to phytoplankton acclimation. The observed variability in the light absorption coefficient and its components due to various pigments with depth and geographical position at sea, requires further accurate modelling in order to improve satellite remote sensing algorithms and interpretation of ocean colour maps. The aim of this paper is to formulate an improved model of the phytoplankton spectral absorption capacity which takes account of the pigment composition and absorption changes resulting from photo- and chromatic acclimation processes, and the pigment package effect. It is a synthesis of earlier models and the following statistical generalisations: (1) statistical relationships between various pigment group concentrations and light field properties in the sea (described by Majchrowski & Ostrowska 2000, this volume); (2) a model of light absorption by phytoplankton capable of determining the mathematical relationships between the spectral absorption coefficients of the various photosynthetic and photoprotecting pigment groups, and their concentrations in seawater (Woźniak et al. 1999); (3) bio-optical models of light propagation in oceanic Case 1 Waters and Baltic Case 2 Waters (Woźniak et al. 1992a, b, 1995a,b). The generalised model described in this paper permits the total phytoplankton light absorption coefficient in vivo as well as its components related to the various photosynthetic and photoprotecting pigments to be determined using only the surface irradiance PAR(0+) surface chlorophyll concentration Ca(0) and depth z in the sea as input data.
Źródło:
Oceanologia; 2000, 42, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model of the in vivo spectral absorption of algal pigments. Part 2. Practical applications of the model
Autorzy:
Majchrowski, R.
Wozniak, B.
Dera, J.
Ficek, D.
Kaczmarek, S.
Ostrowska, M.
Koblentz-Mishke, O.I.
Powiązania:
https://bibliotekanauki.pl/articles/48872.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
practical application
bio-optical modelling
depth
algal pigment
in vivo
sea
statistical model
phytoplankton
light absorption
Opis:
The article describes applications and accuracy analyses of a statistical model of light absorption by phytoplankton that accounts for the influence of photo- and chromatic acclimation on its absorption properties. Part 1 of this work (seeWoźniak et al. 2000, this volume) describes the mathematical apparatus of the model. Earlier models by Woźniak & Ostrowska (1990) and by Bricaud et al. (1995, 1998) are analysed for comparison. Empirical verification of these three models shows that the new model provides a much better approximation of phytoplankton absorption properties than do the earlier models. The statistical errors in estimating the mean absorption coefficient apl, for example, are σ+ = 36% for the new model, whereas for the earlier models the figures are σ+ = 43% (Bricaud et al. 1995, 1998) and σ+ = 59% (Woźniak & Ostrowska 1990). Example applications are given of the new model illustrating the variability in phytoplankton absorption properties with depth and trophicity of the sea.
Źródło:
Oceanologia; 2000, 42, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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