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Quantum yield of photosynthesis in the Baltic : a new mathematical expression for remote sensing applications

Woźniak B., Ficek D., Ostrowska M., Majchrowski R., Dera J.

Oceanologia

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2007

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No. 49 (4)

527-542

EN

Statistical relationships between the quantum yield of photosynthesis ? and selected environmental factors in the Baltic have been established on the basis of a large quantity of empirical data. The model formula is the product of the theoretical maximum quantum yield [formula]. To a sufficiently good approximation, each of these factors fi appears to be dependent on one or at most two environmental factors, such as temperature, underwater irradiance, surface concentration of chlorophyll a, absorption properties of phytoplankton and optical depth. These dependences have been determined for Baltic Case 2 waters. The quantum yield ?, calculated from known values of these environmental factors, is then applicable in the model algorithm for the remote sensing of Baltic primary production. The statistical error of the approximate quantum yields [Fi} is 62%.

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Practical applications of the multi-component marine photosynthesis model (MCM)

Ficek D., Majchrowski R., Ostrowska M., Kaczmarek S., Woźniak B., Dera J.

Oceanologia

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2003

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No. 45 (3)

395-423

EN

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 break 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.

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Dependence of the photosynthesis quantum yield in oceans on environmental factors

Woźniak B., Dera J., Ficek D., Ostrowska M., Majchrowski R.

Oceanologia

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2002

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No. 44 (4)

439-459

EN

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 Phi is expressed as a product of the theoretical maximum quantum yield PhiMAX = 0.125 atom C 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 Phi is 42%.

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Variability of the portion of functional PS2 reaction centres in the light of a fluorometric study

Ficek D., Ostrowska M., Kuzio M., Pogosyan S. I.

Oceanologia

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2000

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No. 42 (2)

243-250

EN

The paper contains a preliminary analysis of the links between the portion fc of functional PS2 reaction centres in the photosynthetic apparatus of marine phytoplankton and environmental factors. The analysis is based inter alia on fluorometric measurements of fc (see Kolber & Falkowski 1993) in water sampled from different depths and trophic types of sea. From the statistical generalisations was derived an analytical form of the relationship between fc, and the optical depth and trophic type of sea (the trophicity index was taken to be the surface concentration of chlorophyll a). According to this relationship, fc rises as the trophicity of the sea does so. Moreover, there is a certain optimal optical depth for each type of water at which the number of functional PS2 reaction centres reaches a maximum. Above or below this depth the value of fc falls. At the present stage of investigations it seems reasonable to assume that this drop in the number of functional PS2 reaction centres close to the surface is due to the destructive effect of excessive irradiance. On the other hand, their reduced number at greater depths, below the fc maximum, can be attributed to the deficit of light and the consequent destruction of reaction centres.